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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1506.03654">arXiv:1506.03654</a> <span> [<a href="https://arxiv.org/pdf/1506.03654">pdf</a>, <a href="https://arxiv.org/format/1506.03654">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Popular Physics">physics.pop-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Teleparallelism: A New Way to Think the Gravitational Interaction </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1506.03654v1-abstract-short" style="display: inline;"> At the time it celebrates one century of existence, general relativity---Einstein's theory for gravitation---is given a companion theory: the so-called teleparallel gravity, or teleparallelism for short. This new theory is fully equivalent to general relativity in what concerns physical results, but is deeply different from the conceptual point of view. Its characteristics make of teleparallel gra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.03654v1-abstract-full').style.display = 'inline'; document.getElementById('1506.03654v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.03654v1-abstract-full" style="display: none;"> At the time it celebrates one century of existence, general relativity---Einstein's theory for gravitation---is given a companion theory: the so-called teleparallel gravity, or teleparallelism for short. This new theory is fully equivalent to general relativity in what concerns physical results, but is deeply different from the conceptual point of view. Its characteristics make of teleparallel gravity an appealing theory, which provides an entirely new way to think the gravitational interaction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.03654v1-abstract-full').style.display = 'none'; document.getElementById('1506.03654v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages. English translation of the Portuguese version published in Ciencia Hoje 55 (2015) 32</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Ciencia Hoje 55 (2015) 32 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0812.3438">arXiv:0812.3438</a> <span> [<a href="https://arxiv.org/pdf/0812.3438">pdf</a>, <a href="https://arxiv.org/ps/0812.3438">ps</a>, <a href="https://arxiv.org/format/0812.3438">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1134/S020228930904001X">10.1134/S020228930904001X <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> De Sitter Special Relativity: Effects on Cosmology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0812.3438v1-abstract-short" style="display: inline;"> The main consequences of de Sitter Special Relativity to the Standard Cosmological Model of Physical Cosmology are examined. The cosmological constant Lambda appears, in this theory, as a manifestation of the proper conformal current, which must be added to the usual energy-momentum density. As that conformal current itself vanishes in absence of sources, Lambda is ultimately dependent on the ma… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.3438v1-abstract-full').style.display = 'inline'; document.getElementById('0812.3438v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0812.3438v1-abstract-full" style="display: none;"> The main consequences of de Sitter Special Relativity to the Standard Cosmological Model of Physical Cosmology are examined. The cosmological constant Lambda appears, in this theory, as a manifestation of the proper conformal current, which must be added to the usual energy-momentum density. As that conformal current itself vanishes in absence of sources, Lambda is ultimately dependent on the matter content, and can in principle be calculated. A present-day value very close to that given by the crossed supernova/BBR data is obtained through simple and reasonable approximations. Also a primeval inflation of polynomial type is found, and the usual notion of co-moving observer is slightly modified. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.3438v1-abstract-full').style.display = 'none'; document.getElementById('0812.3438v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 December, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Grav.Cosmol.15:287-294,2009 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0812.0034">arXiv:0812.0034</a> <span> [<a href="https://arxiv.org/pdf/0812.0034">pdf</a>, <a href="https://arxiv.org/ps/0812.0034">ps</a>, <a href="https://arxiv.org/format/0812.0034">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Inertia and gravitation in teleparallel gravity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Lucas%2C+T+G">Tiago Gribl Lucas</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0812.0034v2-abstract-short" style="display: inline;"> Using the fact that teleparallel gravity allows a separation between gravitation and inertia, explicit expressions for the gravitational and the inertial energy-momentum densities are obtained. It is shown that, like all other fields of nature, gravitation alone has a tensorial energy-momentum density which in a general frame is conserved in the covariant sense. Together with the inertial energy… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.0034v2-abstract-full').style.display = 'inline'; document.getElementById('0812.0034v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0812.0034v2-abstract-full" style="display: none;"> Using the fact that teleparallel gravity allows a separation between gravitation and inertia, explicit expressions for the gravitational and the inertial energy-momentum densities are obtained. It is shown that, like all other fields of nature, gravitation alone has a tensorial energy-momentum density which in a general frame is conserved in the covariant sense. Together with the inertial energy-momentum density, they form a pseudotensor which is conserved in the ordinary sense. An analysis of the role played by the gravitational and the inertial densities in the computation of the total energy and momentum of gravity is presented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0812.0034v2-abstract-full').style.display = 'none'; document.getElementById('0812.0034v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 August, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 November, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, no figures. Version 2: presentation changes, including a new title, to better express the results of the manuscript</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0809.2911">arXiv:0809.2911</a> <span> [<a href="https://arxiv.org/pdf/0809.2911">pdf</a>, <a href="https://arxiv.org/ps/0809.2911">ps</a>, <a href="https://arxiv.org/format/0809.2911">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10773-009-0236-2">10.1007/s10773-009-0236-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nonlinear Gravitational Waves: Their Form and Effects </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=da+Rocha%2C+R">Roldao da Rocha</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0809.2911v2-abstract-short" style="display: inline;"> A gravitational wave must be nonlinear to be able to transport its own source, that is, energy and momentum. A physical gravitational wave, therefore, cannot be represented by a solution to a linear wave equation. Relying on this property, the second-order solution describing such physical waves is obtained. The effects they produce on free particles are found to consist of nonlinear oscillation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0809.2911v2-abstract-full').style.display = 'inline'; document.getElementById('0809.2911v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0809.2911v2-abstract-full" style="display: none;"> A gravitational wave must be nonlinear to be able to transport its own source, that is, energy and momentum. A physical gravitational wave, therefore, cannot be represented by a solution to a linear wave equation. Relying on this property, the second-order solution describing such physical waves is obtained. The effects they produce on free particles are found to consist of nonlinear oscillations along the direction of propagation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0809.2911v2-abstract-full').style.display = 'none'; document.getElementById('0809.2911v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 February, 2010; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 September, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, no figures. v2: presentation changes aiming at clarifying the text; matches published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Theor.Phys.49:549-563,2010 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0805.2584">arXiv:0805.2584</a> <span> [<a href="https://arxiv.org/pdf/0805.2584">pdf</a>, <a href="https://arxiv.org/ps/0805.2584">ps</a>, <a href="https://arxiv.org/format/0805.2584">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/S0218271808013972">10.1142/S0218271808013972 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Is Physics Asking for a New Kinematics? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0805.2584v2-abstract-short" style="display: inline;"> It is discussed whether some of the consistency problems of present-day physics could be solved by replacing special relativity, whose underlying kinematics is ruled by the Poincare' group, by de Sitter relativity, with underlying kinematics ruled by the de Sitter group. In contrast to ordinary special relativity, which seems to fail at the Planck scale, this new relativity is "universal" in the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0805.2584v2-abstract-full').style.display = 'inline'; document.getElementById('0805.2584v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0805.2584v2-abstract-full" style="display: none;"> It is discussed whether some of the consistency problems of present-day physics could be solved by replacing special relativity, whose underlying kinematics is ruled by the Poincare' group, by de Sitter relativity, with underlying kinematics ruled by the de Sitter group. In contrast to ordinary special relativity, which seems to fail at the Planck scale, this new relativity is "universal" in the sense that it holds at all energy scales. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0805.2584v2-abstract-full').style.display = 'none'; document.getElementById('0805.2584v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 March, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 May, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, no figures; Honorable Mention in the Gravity Research Foundation essay contest, 2008. V2: Small presentation change, reference added; matches published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Mod.Phys.D17:2485-2493,2009 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0801.4148">arXiv:0801.4148</a> <span> [<a href="https://arxiv.org/pdf/0801.4148">pdf</a>, <a href="https://arxiv.org/ps/0801.4148">ps</a>, <a href="https://arxiv.org/format/0801.4148">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Gravitation: in search of the missing torsion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0801.4148v1-abstract-short" style="display: inline;"> A linear Lorentz connection has always two fundamental derived characteristics: curvature and torsion. The latter is assumed to vanish in general relativity. Three gravitational models involving non-vanishing torsion are examined: teleparallel gravity, Einstein-Cartan, and new general relativity. Their dependability is critically examined. Although a final answer can only be given by experience,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0801.4148v1-abstract-full').style.display = 'inline'; document.getElementById('0801.4148v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0801.4148v1-abstract-full" style="display: none;"> A linear Lorentz connection has always two fundamental derived characteristics: curvature and torsion. The latter is assumed to vanish in general relativity. Three gravitational models involving non-vanishing torsion are examined: teleparallel gravity, Einstein-Cartan, and new general relativity. Their dependability is critically examined. Although a final answer can only be given by experience, it is argued that teleparallel gravity provides the most consistent approach. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0801.4148v1-abstract-full').style.display = 'none'; document.getElementById('0801.4148v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 January, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages. To be published in the special issue on torsion of the Annales de la Fondation Louis de Broglie, volume editor V. Dvoeglazov</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Ann. Fond. Louis de Broglie 32 (2007) 229 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0801.0705">arXiv:0801.0705</a> <span> [<a href="https://arxiv.org/pdf/0801.0705">pdf</a>, <a href="https://arxiv.org/ps/0801.0705">ps</a>, <a href="https://arxiv.org/format/0801.0705">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1140/epjc/s10052-008-0780-6">10.1140/epjc/s10052-008-0780-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realistic Equations of State for the Primeval Universe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Cuzinatto%2C+R+R">R. R. Cuzinatto</a>, <a href="/search/gr-qc?searchtype=author&query=Medeiros%2C+L+G">L. G. Medeiros</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0801.0705v2-abstract-short" style="display: inline;"> Early universe equations of state including realistic interactions between constituents are built up. Under certain reasonable assumptions, these equations are able to generate an inflationary regime prior to the nucleosynthesis period. The resulting accelerated expansion is intense enough to solve the flatness and horizon problems. In the cases of curvature parameter 魏equal to 0 or +1, the mode… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0801.0705v2-abstract-full').style.display = 'inline'; document.getElementById('0801.0705v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0801.0705v2-abstract-full" style="display: none;"> Early universe equations of state including realistic interactions between constituents are built up. Under certain reasonable assumptions, these equations are able to generate an inflationary regime prior to the nucleosynthesis period. The resulting accelerated expansion is intense enough to solve the flatness and horizon problems. In the cases of curvature parameter 魏equal to 0 or +1, the model is able to avoid the initial singularity and offers a natural explanation for why the universe is in expansion. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0801.0705v2-abstract-full').style.display = 'none'; document.getElementById('0801.0705v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 October, 2008; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 January, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2008. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">32 pages, 5 figures. Citations added in this version. Accepted EPJC</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Eur.Phys.J.C58:483-497,2008 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0711.2274">arXiv:0711.2274</a> <span> [<a href="https://arxiv.org/pdf/0711.2274">pdf</a>, <a href="https://arxiv.org/ps/0711.2274">ps</a>, <a href="https://arxiv.org/format/0711.2274">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10701-008-9258-5">10.1007/s10701-008-9258-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> de Sitter Relativity: a New Road to Quantum Gravity? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0711.2274v3-abstract-short" style="display: inline;"> The Poincare' group generalizes the Galilei group for high-velocity kinematics. The de Sitter group is assumed to go one step further, generalizing Poincare' as the group governing high-energy kinematics. In other words, ordinary special relativity is here replaced by de Sitter relativity. In this theory, the cosmological constant is no longer a free parameter, and can be determined in terms of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.2274v3-abstract-full').style.display = 'inline'; document.getElementById('0711.2274v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0711.2274v3-abstract-full" style="display: none;"> The Poincare' group generalizes the Galilei group for high-velocity kinematics. The de Sitter group is assumed to go one step further, generalizing Poincare' as the group governing high-energy kinematics. In other words, ordinary special relativity is here replaced by de Sitter relativity. In this theory, the cosmological constant is no longer a free parameter, and can be determined in terms of other quantities. When applied to the whole universe, it is able to predict the value of the cosmological constant and to explain the cosmic coincidence. When applied to the propagation of ultra-high energy photons, it gives a good estimate of the time delay observed in extragalactic gamma-ray flares. It can, for this reason, be considered a new paradigm to approach the quantum gravity problem. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0711.2274v3-abstract-full').style.display = 'none'; document.getElementById('0711.2274v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 November, 2008; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 November, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, no figures. v3: Important presentation changes intended to clarify some points of the previous version; title slightly changed and references added. Version to be published in Foundations of Physics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Found.Phys.39:1-19,2009 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0710.0610">arXiv:0710.0610</a> <span> [<a href="https://arxiv.org/pdf/0710.0610">pdf</a>, <a href="https://arxiv.org/ps/0710.0610">ps</a>, <a href="https://arxiv.org/format/0710.0610">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.2827302">10.1063/1.2827302 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> de Sitter Relativity and Quantum Physics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Mayor%2C+C+S+O">C. S. O. Mayor</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0710.0610v1-abstract-short" style="display: inline;"> In the presence of a cosmological constant, interpreted as a purely geometric entity, absence of matter is represented by a de Sitter spacetime. As a consequence, ordinary Poincare' special relativity is no longer valid and must be replaced by a de Sitter special relativity. By considering the kinematics of a spinless particle in a de Sitter spacetime, we study the geodesics of this spacetime, t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.0610v1-abstract-full').style.display = 'inline'; document.getElementById('0710.0610v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0710.0610v1-abstract-full" style="display: none;"> In the presence of a cosmological constant, interpreted as a purely geometric entity, absence of matter is represented by a de Sitter spacetime. As a consequence, ordinary Poincare' special relativity is no longer valid and must be replaced by a de Sitter special relativity. By considering the kinematics of a spinless particle in a de Sitter spacetime, we study the geodesics of this spacetime, the ensuing definitions of canonical momenta, and explore possible implications for quantum mechanics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0710.0610v1-abstract-full').style.display = 'none'; document.getElementById('0710.0610v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 October, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in "Quantum Theory: Reconsideration of Foundations 4", 11-16 June 2007, Vaxjo University, Sweden (AIP Conference Proceedings, ed. by G. Adenier, A. Khrennikov and T. Nieuwenhuizen). 10 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> AIP Conf.Proc.962:175-184,2007 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0709.3947">arXiv:0709.3947</a> <span> [<a href="https://arxiv.org/pdf/0709.3947">pdf</a>, <a href="https://arxiv.org/ps/0709.3947">ps</a>, <a href="https://arxiv.org/format/0709.3947">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Lorentz transformations in de Sitter relativity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Mayor%2C+C+S+O">C. S. O. Mayor</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0709.3947v1-abstract-short" style="display: inline;"> The properties of Lorentz transformations in de Sitter relativity are studied. It is shown that, in addition to leaving invariant the velocity of light, they also leave invariant the length-scale related to the curvature of the de Sitter spacetime. The basic conclusion is that it is possible to have an invariant length parameter without breaking the Lorentz symmetry. This result may have importa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0709.3947v1-abstract-full').style.display = 'inline'; document.getElementById('0709.3947v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0709.3947v1-abstract-full" style="display: none;"> The properties of Lorentz transformations in de Sitter relativity are studied. It is shown that, in addition to leaving invariant the velocity of light, they also leave invariant the length-scale related to the curvature of the de Sitter spacetime. The basic conclusion is that it is possible to have an invariant length parameter without breaking the Lorentz symmetry. This result may have important implications for the study of quantum kinematics, and in particular for quantum gravity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0709.3947v1-abstract-full').style.display = 'none'; document.getElementById('0709.3947v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 September, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, no figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0709.1603">arXiv:0709.1603</a> <span> [<a href="https://arxiv.org/pdf/0709.1603">pdf</a>, <a href="https://arxiv.org/ps/0709.1603">ps</a>, <a href="https://arxiv.org/format/0709.1603">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10701-007-9180-2">10.1007/s10701-007-9180-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Nonlinear Essence of Gravitational Waves </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0709.1603v1-abstract-short" style="display: inline;"> A critical review of gravitational wave theory is made. It is pointed out that the usual linear approach to the gravitational wave theory is neither conceptually consistent nor mathematically justified. Relying upon that analysis it is then argued that -- analogously to a Yang-Mills propagating field, which must be nonlinear to carry its gauge charge -- a gravitational wave must necessarily be n… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0709.1603v1-abstract-full').style.display = 'inline'; document.getElementById('0709.1603v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0709.1603v1-abstract-full" style="display: none;"> A critical review of gravitational wave theory is made. It is pointed out that the usual linear approach to the gravitational wave theory is neither conceptually consistent nor mathematically justified. Relying upon that analysis it is then argued that -- analogously to a Yang-Mills propagating field, which must be nonlinear to carry its gauge charge -- a gravitational wave must necessarily be nonlinear to transport its own charge -- that is, energy-momentum. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0709.1603v1-abstract-full').style.display = 'none'; document.getElementById('0709.1603v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 September, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Plain Latex, 13 pages, no figures. Accepted for publication in Foundations of Physiscs</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Found.Phys.37:1503-1517,2007 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0705.1369">arXiv:0705.1369</a> <span> [<a href="https://arxiv.org/pdf/0705.1369">pdf</a>, <a href="https://arxiv.org/ps/0705.1369">ps</a>, <a href="https://arxiv.org/format/0705.1369">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/S0218271808012541">10.1142/S0218271808012541 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Interacting Constituents in Cosmology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Cuzinatto%2C+R+R">R. R. Cuzinatto</a>, <a href="/search/gr-qc?searchtype=author&query=Medeiros%2C+L+G">L. G. Medeiros</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0705.1369v2-abstract-short" style="display: inline;"> Universe evolution, as described by Friedmann's equations, is determined by source terms fixed by the choice of pressure $\times$ energy-density equations of state $p(蟻)$. The usual approach in Cosmology considers equations of state accounting only for kinematic terms, ignoring the contribution from the interactions between the particles constituting the source fluid. In this work the importance… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0705.1369v2-abstract-full').style.display = 'inline'; document.getElementById('0705.1369v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0705.1369v2-abstract-full" style="display: none;"> Universe evolution, as described by Friedmann's equations, is determined by source terms fixed by the choice of pressure $\times$ energy-density equations of state $p(蟻)$. The usual approach in Cosmology considers equations of state accounting only for kinematic terms, ignoring the contribution from the interactions between the particles constituting the source fluid. In this work the importance of these neglected terms is emphasized. A systematic method, based on the Statistical Mechanics of real fluids, is proposed to include them. A toy-model is presented which shows how such interaction terms can engender significant cosmological effects. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0705.1369v2-abstract-full').style.display = 'none'; document.getElementById('0705.1369v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 May, 2007; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 May, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 6 figures. It includes results presented in "Cosmic Acceleration from Elementary Interactions" [arXiv:gr-qc/0512135]. Citations added in v.2</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Mod.Phys.D17:857-879,2008 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0702065">arXiv:gr-qc/0702065</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0702065">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0702065">ps</a>, <a href="https://arxiv.org/format/gr-qc/0702065">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.2752487">10.1063/1.2752487 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Some Implications of the Cosmological Constant to Fundamental Physics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0702065v1-abstract-short" style="display: inline;"> In the presence of a cosmological constant, ordinary Poincare' special relativity is no longer valid and must be replaced by a de Sitter special relativity, in which Minkowski space is replaced by a de Sitter spacetime. In consequence, the ordinary notions of energy and momentum change, and will satisfy a different kinematic relation. Such a theory is a different kind of a doubly special relativ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0702065v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0702065v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0702065v1-abstract-full" style="display: none;"> In the presence of a cosmological constant, ordinary Poincare' special relativity is no longer valid and must be replaced by a de Sitter special relativity, in which Minkowski space is replaced by a de Sitter spacetime. In consequence, the ordinary notions of energy and momentum change, and will satisfy a different kinematic relation. Such a theory is a different kind of a doubly special relativity. Since the only difference between the Poincare' and the de Sitter groups is the replacement of translations by certain linear combinations of translations and proper conformal transformations, the net result of this change is ultimately the breakdown of ordinary translational invariance. From the experimental point of view, therefore, a de Sitter special relativity might be probed by looking for possible violations of translational invariance. If we assume the existence of a connection between the energy scale of an experiment and the local value of the cosmological constant, there would be changes in the kinematics of massive particles which could hopefully be detected in high-energy experiments. Furthermore, due to the presence of a horizon, the usual causal structure of spacetime would be significantly modified at the Planck scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0702065v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0702065v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 February, 2007; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2007. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, lecture presented at the "XIIth Brazilian School of Cosmology and Gravitation", Mangaratiba, Rio de Janeiro, September 10-23, 2006</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0606122">arXiv:gr-qc/0606122</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0606122">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0606122">ps</a>, <a href="https://arxiv.org/format/gr-qc/0606122">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0264-9381/24/6/002">10.1088/0264-9381/24/6/002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> de Sitter special relativity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0606122v2-abstract-short" style="display: inline;"> A special relativity based on the de Sitter group is introduced, which is the theory that might hold up in the presence of a non-vanishing cosmological constant. Like ordinary special relativity, it retains the quotient character of spacetime, and a notion of homogeneity. As a consequence, the underlying spacetime will be a de Sitter spacetime, whose associated kinematics will differ from that o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0606122v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0606122v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0606122v2-abstract-full" style="display: none;"> A special relativity based on the de Sitter group is introduced, which is the theory that might hold up in the presence of a non-vanishing cosmological constant. Like ordinary special relativity, it retains the quotient character of spacetime, and a notion of homogeneity. As a consequence, the underlying spacetime will be a de Sitter spacetime, whose associated kinematics will differ from that of ordinary special relativity. The corresponding modified notions of energy and momentum are obtained, and the exact relationship between them, which is invariant under a re-scaling of the involved quantities, explicitly exhibited. Since the de Sitter group can be considered a particular deformation of the Poincar茅 group, this theory turns out to be a specific kind of deformed (or doubly) special relativity. Some experimental consequences, as well as the causal structure of spacetime--modified by the presence of the de Sitter horizon--are briefly discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0606122v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0606122v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 February, 2007; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 June, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2006. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">V2: Some presentation changes; a new section introduced, with a discussion about possible phenomenological consequences; new references added; version to be published in Classical and Quantum Gravity</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Class.Quant.Grav.24:1385-1404,2007 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0603122">arXiv:gr-qc/0603122</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0603122">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0603122">ps</a>, <a href="https://arxiv.org/format/gr-qc/0603122">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.2399585">10.1063/1.2399585 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Bringing Together Gravity and the Quanta </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Guillen%2C+L+C+T">L. C. T. Guillen</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0603122v1-abstract-short" style="display: inline;"> Due to its underlying gauge structure, teleparallel gravity achieves a separation between inertial and gravitational effects. It can, in consequence, describe the isolated gravitational interaction without resorting to the equivalence principle, and is able to provide a tensorial definition for the energy-momentum density of the gravitational field. Considering the conceptual conflict between th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0603122v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0603122v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0603122v1-abstract-full" style="display: none;"> Due to its underlying gauge structure, teleparallel gravity achieves a separation between inertial and gravitational effects. It can, in consequence, describe the isolated gravitational interaction without resorting to the equivalence principle, and is able to provide a tensorial definition for the energy-momentum density of the gravitational field. Considering the conceptual conflict between the local equivalence principle and the nonlocal uncertainty principle, the replacement of general relativity by its teleparallel equivalent can be considered an important step towards a prospective reconciliation between gravitation and quantum mechanics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0603122v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0603122v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 March, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2006. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages. Contribution to the proceedings of the Albert Einstein Century International Conference, Paris, 18-22 July, 2005</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0512135">arXiv:gr-qc/0512135</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0512135">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0512135">ps</a>, <a href="https://arxiv.org/format/gr-qc/0512135">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Cosmic Acceleration from Elementary Interactions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Cuzinatto%2C+R+R">R. R. Cuzinatto</a>, <a href="/search/gr-qc?searchtype=author&query=Medeiros%2C+L+G">L. G. Medeiros</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0512135v1-abstract-short" style="display: inline;"> It is possible to generate an accelerated period of expansion from reasonable potentials acting between the universe particle constituents. The pressure of primordial nucleons interacting via a simple nuclear potential is obtained via Mayer's cluster expansion technique. The attractive part of the potential engenders a negative pressure and may therefore be responsible for the cosmic acceleratio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0512135v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0512135v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0512135v1-abstract-full" style="display: none;"> It is possible to generate an accelerated period of expansion from reasonable potentials acting between the universe particle constituents. The pressure of primordial nucleons interacting via a simple nuclear potential is obtained via Mayer's cluster expansion technique. The attractive part of the potential engenders a negative pressure and may therefore be responsible for the cosmic acceleration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0512135v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0512135v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 December, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2005. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 3 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0509051">arXiv:gr-qc/0509051</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0509051">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0509051">ps</a>, <a href="https://arxiv.org/format/gr-qc/0509051">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1063/1.2158724">10.1063/1.2158724 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravity and the Quantum: Are they Reconcilable? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0509051v1-abstract-short" style="display: inline;"> General relativity and quantum mechanics are conflicting theories. The seeds of discord are the fundamental principles on which these theories are grounded. General relativity, on one hand, is based on the equivalence principle, whose strong version establishes the local equivalence between gravitation and inertia. Quantum mechanics, on the other hand, is fundamentally based on the uncertainty p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509051v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0509051v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0509051v1-abstract-full" style="display: none;"> General relativity and quantum mechanics are conflicting theories. The seeds of discord are the fundamental principles on which these theories are grounded. General relativity, on one hand, is based on the equivalence principle, whose strong version establishes the local equivalence between gravitation and inertia. Quantum mechanics, on the other hand, is fundamentally based on the uncertainty principle, which is essentially nonlocal in the sense that a particle does not follow one trajectory, but infinitely many trajectories, each one with a different probability. This difference precludes the existence of a quantum version of the strong equivalence principle, and consequently of a quantum version of general relativity. Furthermore, there are compelling experimental evidences that a quantum object in the presence of a gravitational field violates the weak equivalence principle. Now it so happens that, in addition to general relativity, gravitation has an alternative, though equivalent description, given by teleparallel gravity, a gauge theory for the translation group. In this theory torsion, instead of curvature, is assumed to represent the gravitational field. These two descriptions lead to the same classical results, but are conceptually different. In general relativity, curvature geometrizes the interaction, while torsion in teleparallel gravity acts as a force, similar to the Lorentz force of electrodynamics. Because of this peculiar property, teleparallel gravity describes the gravitational interaction without requiring any of the equivalence principles. The replacement of general relativity by teleparallel gravity may, in consequence, lead to a conceptual reconciliation of gravitation with quantum mechanics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509051v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0509051v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 September, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2005. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 2 figures. Talk presented at the conference "Quantum Theory: Reconsideration of Foundations-3", June 6-11, 2005, Vaxjo University, Vaxjo, Sweden</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0509003">arXiv:gr-qc/0509003</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0509003">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0509003">ps</a>, <a href="https://arxiv.org/format/gr-qc/0509003">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10714-007-0490-7">10.1007/s10714-007-0490-7 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Primeval symmetries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Cuzinatto%2C+R+R">R. R. Cuzinatto</a>, <a href="/search/gr-qc?searchtype=author&query=Medeiros%2C+L+G">L. G. Medeiros</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0509003v3-abstract-short" style="display: inline;"> A detailed examination of the Killing equations in Robertson-Walker coordinates shows how the addition of matter and/or radiation to a de Sitter Universe breaks the symmetry generated by four of its Killing fields. The product U = (a^2)(dH/dt) of the squared scale parameter by the time-derivative of the Hubble function encapsulates the relationship between the two cases: the symmetry is maximal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509003v3-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0509003v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0509003v3-abstract-full" style="display: none;"> A detailed examination of the Killing equations in Robertson-Walker coordinates shows how the addition of matter and/or radiation to a de Sitter Universe breaks the symmetry generated by four of its Killing fields. The product U = (a^2)(dH/dt) of the squared scale parameter by the time-derivative of the Hubble function encapsulates the relationship between the two cases: the symmetry is maximal when U is a constant, and reduces to the six-parameter symmetry of a generic Friedmann-Robertson-Walker model when it is not. As the fields physical interpretation is not clear in these coordinates, comparison is made with the Killing fields in static coordinates, whose interpretation is made clearer by their direct relationship to the Poincare group generators via Wigner-Inonu contractions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0509003v3-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0509003v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 August, 2007; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 August, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2005. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 2 tables; published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Gen.Rel.Grav.39:1813-1832,2007 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0508073">arXiv:gr-qc/0508073</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0508073">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0508073">ps</a>, <a href="https://arxiv.org/format/gr-qc/0508073">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10701-006-9076-6">10.1007/s10701-006-9076-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Analytic solutions for the $螞$-FRW Model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Cuzinatto%2C+R+R">R. R. Cuzinatto</a>, <a href="/search/gr-qc?searchtype=author&query=Medeiros%2C+L+G">L. G. Medeiros</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0508073v4-abstract-short" style="display: inline;"> The high precision attained by cosmological data in the last few years has increased the interest in exact solutions. Analytic expressions for solutions in the Standard Model are presented here for all combinations of $螞= 0$, $螞\ne 0$, $魏= 0$ and $魏\ne 0$, in the presence and absence of radiation and nonrelativistic matter. The most complete case (here called the $螞纬CDM$ Model) has… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0508073v4-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0508073v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0508073v4-abstract-full" style="display: none;"> The high precision attained by cosmological data in the last few years has increased the interest in exact solutions. Analytic expressions for solutions in the Standard Model are presented here for all combinations of $螞= 0$, $螞\ne 0$, $魏= 0$ and $魏\ne 0$, in the presence and absence of radiation and nonrelativistic matter. The most complete case (here called the $螞纬CDM$ Model) has $螞\ne 0, 魏\ne 0$, and supposes the presence of radiation and dust. It exhibits clearly the recent onset of acceleration. The treatment includes particular models of interest such as the $螞$CDM Model (which includes the cosmological constant plus cold dark matter as source constituents). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0508073v4-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0508073v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 November, 2007; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 August, 2005; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2005. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 2 figures; published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Found.Phys.36:1736-1752,2006 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0412032">arXiv:gr-qc/0412032</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0412032">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0412032">ps</a>, <a href="https://arxiv.org/format/gr-qc/0412032">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> General Relativity as a Genuine Connection Theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Arcos%2C+H+I">H. I. Arcos</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0412032v1-abstract-short" style="display: inline;"> The Palatini formulation is used to develop a genuine connection theory for general relativity, in which the gravitational field is represented by a Lorentz-valued spin connection. The existence of a tetrad field, given by the Fock-Ivanenko covariant derivative of the tangent-space coordinates, implies a coupling between the spin connection and the coordinate vector-field, which turns out to be… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0412032v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0412032v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0412032v1-abstract-full" style="display: none;"> The Palatini formulation is used to develop a genuine connection theory for general relativity, in which the gravitational field is represented by a Lorentz-valued spin connection. The existence of a tetrad field, given by the Fock-Ivanenko covariant derivative of the tangent-space coordinates, implies a coupling between the spin connection and the coordinate vector-field, which turns out to be the responsible for the onset of curvature. This connection-coordinate coupling can thus be considered as the very foundation of the gravitational interaction. The peculiar form of the tetrad field is shown to reduce both Bianchi identities of general relativity to a single one, which brings this theory closer to the gauge theories describing the other fundamental interactions of Nature. Some further properties of this approach are also examined. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0412032v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0412032v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 December, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2004. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">LaTeX, 14 pages. Talk presented at the colloquium "Theory and Experiment in Cosmology and Gravitation", in honor of Jose Plinio Baptista on the occasion of his 70th birthday (September 22-24, 2004, Vitoria, Brazil). To be published in the proceedings</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0410042">arXiv:gr-qc/0410042</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0410042">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0410042">ps</a>, <a href="https://arxiv.org/format/gr-qc/0410042">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/9789812704030_0142">10.1142/9789812704030_0142 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Doing without the Equivalence Principle </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0410042v1-abstract-short" style="display: inline;"> In Einstein's general relativity, geometry replaces the concept of force in the description of the gravitation interaction. Such an approach rests on the universality of free-fall--the weak equivalence principle--and would break down without it. On the other hand, the teleparallel version of general relativity, a gauge theory for the translation group, describes the gravitational interaction by… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0410042v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0410042v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0410042v1-abstract-full" style="display: none;"> In Einstein's general relativity, geometry replaces the concept of force in the description of the gravitation interaction. Such an approach rests on the universality of free-fall--the weak equivalence principle--and would break down without it. On the other hand, the teleparallel version of general relativity, a gauge theory for the translation group, describes the gravitational interaction by a force similar to the Lorentz force of electromagnetism, a non-universal interaction. It is shown that, similarly to the Maxwell's description of electromagnetism, the teleparallel gauge approach provides a consistent theory for gravitation even in the absence of the weak equivalence principle. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0410042v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0410042v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 October, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2004. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 pages, no figures. Talk presented at the "Tenth Marcel Grossmann Meeting", July 20 to 26, 2003, Rio de Janeiro, Brazil; to be published in the Proceedings (World Scientific, Singapore, 2005)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0405104">arXiv:gr-qc/0405104</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0405104">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0405104">ps</a>, <a href="https://arxiv.org/format/gr-qc/0405104">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1142/S0218271804006279">10.1142/S0218271804006279 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cosmological Term and Fundamental Physics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0405104v1-abstract-short" style="display: inline;"> A nonvanishing cosmological term in Einstein's equations implies a nonvanishing spacetime curvature even in absence of any kind of matter. It would, in consequence, affect many of the underlying kinematic tenets of physical theory. The usual commutative spacetime translations of the Poincare' group would be replaced by the mixed conformal translations of the de Sitter group, leading to obvious a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0405104v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0405104v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0405104v1-abstract-full" style="display: none;"> A nonvanishing cosmological term in Einstein's equations implies a nonvanishing spacetime curvature even in absence of any kind of matter. It would, in consequence, affect many of the underlying kinematic tenets of physical theory. The usual commutative spacetime translations of the Poincare' group would be replaced by the mixed conformal translations of the de Sitter group, leading to obvious alterations in elementary concepts such as time, energy and momentum. Although negligible at small scales, such modifications may come to have important consequences both in the large and for the inflationary picture of the early Universe. A qualitative discussion is presented which suggests deep changes in Hamiltonian, Quantum and Statistical Mechanics. In the primeval universe as described by the standard cosmological model, in particular, the equations of state of the matter sources could be quite different from those usually introduced. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0405104v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0405104v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 May, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2004. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX, 4 pages. Selected for Honorable Mention in the Annual Essay Competition of the Gravity Research Foundation for the year 2004</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Mod.Phys. D13 (2004) 2241-2248 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0403099">arXiv:gr-qc/0403099</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0403099">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0403099">ps</a>, <a href="https://arxiv.org/format/gr-qc/0403099">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.geomphys.2005.06.004">10.1016/j.geomphys.2005.06.004 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Singular Conformal Spacetime </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0403099v2-abstract-short" style="display: inline;"> The infinite cosmological "constant" limit of the de Sitter solutions to Einstein's equation is studied. The corresponding spacetime is a singular, four-dimensional cone-space, transitive under proper conformal transformations, which constitutes a new example of maximally-symmetric spacetime. Grounded on its geometric and thermodynamic properties, some speculations are made in connection with th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0403099v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0403099v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0403099v2-abstract-full" style="display: none;"> The infinite cosmological "constant" limit of the de Sitter solutions to Einstein's equation is studied. The corresponding spacetime is a singular, four-dimensional cone-space, transitive under proper conformal transformations, which constitutes a new example of maximally-symmetric spacetime. Grounded on its geometric and thermodynamic properties, some speculations are made in connection with the primordial universe. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0403099v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0403099v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 June, 2005; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 March, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2004. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX4, 10 pages, 1 eps figure. Presentation changes, including a new title; section II.E, on the thermodynamic properties of the de Sitter horizon, completely revised. Version to be published in Journal of Geometry and Physics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J.Geom.Phys. 56 (2006) 1042-1056 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0402022">arXiv:gr-qc/0402022</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0402022">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0402022">ps</a>, <a href="https://arxiv.org/format/gr-qc/0402022">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Spin and Anholonomy in General Relativity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barros%2C+P+B">P. B. Barros</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0402022v2-abstract-short" style="display: inline;"> In the general case, torsion couples to the spin current of the Dirac field. In General Relativity, the apparent torsion field to which the spin current of the Dirac field couples is a mere manifestation of the tetrad anholonomy. Seen from the tetrad frame itself, it has for components the anholonomy coefficients. The latter represent mechanical characteristics of the frame. In the teleparallel… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0402022v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0402022v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0402022v2-abstract-full" style="display: none;"> In the general case, torsion couples to the spin current of the Dirac field. In General Relativity, the apparent torsion field to which the spin current of the Dirac field couples is a mere manifestation of the tetrad anholonomy. Seen from the tetrad frame itself, it has for components the anholonomy coefficients. The latter represent mechanical characteristics of the frame. In the teleparallel equivalent of General Relativity, this coefficient turns out to be the only torsion present. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0402022v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0402022v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 February, 2004; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 February, 2004; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2004. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Authors list corrected. Revtex4, 11 pages. Contribution to the volume "Roberto Salmeron Festschrift: A Master and Friend", edited by R. Aldrovandi, A. Santoro and J. M. Gago (AIAFEX, Rio de Janeiro, 2004)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0312017">arXiv:gr-qc/0312017</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0312017">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0312017">ps</a>, <a href="https://arxiv.org/format/gr-qc/0312017">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> </div> <p class="title is-5 mathjax"> Time-Varying Cosmological Term: Emergence and Fate of a FRW Universe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Almeida%2C+J+P+B">J. P. Beltran Almeida</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0312017v3-abstract-short" style="display: inline;"> A time-varying cosmological "constant" Lambda is consistent with Einstein's equation, provided matter and/or radiation is created or destroyed to compensate for it. Supposing an empty primordial universe endowed with a very large cosmological term, matter will emerge gradually as Lambda decays. Provided only radiation or ultrarelativistic matter is initially created, the universe starts in a nea… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0312017v3-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0312017v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0312017v3-abstract-full" style="display: none;"> A time-varying cosmological "constant" Lambda is consistent with Einstein's equation, provided matter and/or radiation is created or destroyed to compensate for it. Supposing an empty primordial universe endowed with a very large cosmological term, matter will emerge gradually as Lambda decays. Provided only radiation or ultrarelativistic matter is initially created, the universe starts in a nearly de Sitter phase, which evolves towards a FRW regime as expansion proceeds. If, at some cosmological time, the cosmological term begins increasing again, as presently observed, expansion will accelerate and matter and/or radiation will be transformed back into dark energy. It is shown that such accelerated expansion is a route towards a new kind of gravitational singular state, characterized by an empty, conformally transitive spacetime in which all energy is dark. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0312017v3-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0312017v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2005; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 December, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2003. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX, 7 pages, no figures. Version 3: title and presentation changes; an appendix and references added. Version to be published in Gravitation & Cosmology</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Grav.Cosmol.11:277-283,2005 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0312008">arXiv:gr-qc/0312008</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0312008">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0312008">ps</a>, <a href="https://arxiv.org/format/gr-qc/0312008">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Selected Topics in Teleparallel Gravity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0312008v1-abstract-short" style="display: inline;"> Teleparallel gravity can be seen as a gauge theory for the translation group. As such, its fundamental field is neither the tetrad nor the metric, but a gauge potential assuming values in the Lie algebra of the translation group. This gauge character makes of teleparallel gravity, despite its equivalence to general relativity, a rather peculiar theory. A first important point is that it does not… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0312008v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0312008v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0312008v1-abstract-full" style="display: none;"> Teleparallel gravity can be seen as a gauge theory for the translation group. As such, its fundamental field is neither the tetrad nor the metric, but a gauge potential assuming values in the Lie algebra of the translation group. This gauge character makes of teleparallel gravity, despite its equivalence to general relativity, a rather peculiar theory. A first important point is that it does not rely on the universality of free fall, and consequently does not require the equivalence principle to describe the gravitational interaction. Another peculiarity is its similarity with Maxwell's theory, which allows an Abelian nonintegrable phase factor approach, and consequently a global formulation for gravitation. Application of these concepts to the motion of spinless particles, as well as to the COW and gravitational Aharonov-Bohm effects are presented and discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0312008v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0312008v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 December, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2003. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX4, 7 pages, 2 eps figures. Talk presented at the "24th National Meeting of the Brazilian Physical Society", section Particles and Fields, Caxambu MG, Brazil, from September/30 to October/04/2003</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Braz.J.Phys.34:1374-1380,2004 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0310110">arXiv:gr-qc/0310110</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0310110">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0310110">ps</a>, <a href="https://arxiv.org/format/gr-qc/0310110">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0264-9381/21/1/004">10.1088/0264-9381/21/1/004 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitation: Global Formulation and Quantum Effects </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0310110v1-abstract-short" style="display: inline;"> A nonintegrable phase-factor global approach to gravitation is developed by using the similarity of teleparallel gravity with electromagnetism. The phase shifts of both the COW and the gravitational Aharonov-Bohm effects are obtained. It is then shown, by considering a simple slit experiment, that in the classical limit the global approach yields the same result as the gravitational Lorentz forc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0310110v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0310110v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0310110v1-abstract-full" style="display: none;"> A nonintegrable phase-factor global approach to gravitation is developed by using the similarity of teleparallel gravity with electromagnetism. The phase shifts of both the COW and the gravitational Aharonov-Bohm effects are obtained. It is then shown, by considering a simple slit experiment, that in the classical limit the global approach yields the same result as the gravitational Lorentz force equation of teleparallel gravity. It represents, therefore, the quantum mechanical version of the classical description provided by the gravitational Lorentz force equation. As teleparallel gravity can be formulated independently of the equivalence principle, it will consequently require no generalization of this principle at the quantum level. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0310110v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0310110v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 October, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2003. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Latex (IOP style), 14 pages, 3 figures. To appear in Classical and Quantum Gravity</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Class.Quant.Grav. 21 (2004) 51-62 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0304106">arXiv:gr-qc/0304106</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0304106">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0304106">ps</a>, <a href="https://arxiv.org/format/gr-qc/0304106">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1023/B:GERG.0000006696.98824.4d">10.1023/B:GERG.0000006696.98824.4d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitation without the equivalence principle </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a>, <a href="/search/gr-qc?searchtype=author&query=Vu%2C+K+H">K. H. Vu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0304106v2-abstract-short" style="display: inline;"> In the general relativistic description of gravitation, geometry replaces the concept of force. This is possible because of the universal character of free fall, and would break down in its absence. On the other hand, the teleparallel version of general relativity is a gauge theory for the translation group and, as such, describes the gravitational interaction by a force similar to the Lorentz f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0304106v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0304106v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0304106v2-abstract-full" style="display: none;"> In the general relativistic description of gravitation, geometry replaces the concept of force. This is possible because of the universal character of free fall, and would break down in its absence. On the other hand, the teleparallel version of general relativity is a gauge theory for the translation group and, as such, describes the gravitational interaction by a force similar to the Lorentz force of electromagnetism, a non-universal interaction. Relying on this analogy it is shown that, although the geometric description of general relativity necessarily requires the existence of the equivalence principle, the teleparallel gauge approach remains a consistent theory for gravitation in its absence. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0304106v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0304106v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 August, 2003; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 April, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2003. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Latex, 11 pages, no figures. Minor presentation changes. Version to appear in Gen. Rel. Grav. (2004)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Gen.Rel.Grav. 36 (2004) 101-110 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0301077">arXiv:gr-qc/0301077</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0301077">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0301077">ps</a>, <a href="https://arxiv.org/format/gr-qc/0301077">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1023/A:1024060732690">10.1023/A:1024060732690 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitation as Anholonomy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barros%2C+P+B">P. B. Barros</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0301077v1-abstract-short" style="display: inline;"> A gravitational field can be seen as the anholonomy of the tetrad fields. This is more explicit in the teleparallel approach, in which the gravitational field-strength is the torsion of the ensuing Weitzenboeck connection. In a tetrad frame, that torsion is just the anholonomy of that frame. The infinitely many tetrad fields taking the Lorentz metric into a given Riemannian metric differ by poin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0301077v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0301077v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0301077v1-abstract-full" style="display: none;"> A gravitational field can be seen as the anholonomy of the tetrad fields. This is more explicit in the teleparallel approach, in which the gravitational field-strength is the torsion of the ensuing Weitzenboeck connection. In a tetrad frame, that torsion is just the anholonomy of that frame. The infinitely many tetrad fields taking the Lorentz metric into a given Riemannian metric differ by point-dependent Lorentz transformations. Inertial frames constitute a smaller infinity of them, differing by fixed-point Lorentz transformations. Holonomic tetrads take the Lorentz metric into itself, and correspond to Minkowski flat spacetime. An accelerated frame is necessarily anholonomic and sees the electromagnetic field strength with an additional term. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0301077v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0301077v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 January, 2003; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2003. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX4, 10 pages, no figures. To appear in Gen. Rel. Grav</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Gen.Rel.Grav. 35 (2003) 991-1005 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0212034">arXiv:gr-qc/0212034</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0212034">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0212034">ps</a>, <a href="https://arxiv.org/format/gr-qc/0212034">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> The Equivalence Principle Revisited </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barros%2C+P+B">P. B. Barros</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0212034v1-abstract-short" style="display: inline;"> A precise formulation of the strong Equivalence Principle is essential to the understanding of the relationship between gravitation and quantum mechanics. The relevant aspects are reviewed in a context including General Relativity, but allowing for the presence of torsion. For the sake of brevity, a concise statement is proposed for the Principle: "An ideal observer immersed in a gravitational f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0212034v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0212034v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0212034v1-abstract-full" style="display: none;"> A precise formulation of the strong Equivalence Principle is essential to the understanding of the relationship between gravitation and quantum mechanics. The relevant aspects are reviewed in a context including General Relativity, but allowing for the presence of torsion. For the sake of brevity, a concise statement is proposed for the Principle: "An ideal observer immersed in a gravitational field can choose a reference frame in which gravitation goes unnoticed". This statement is given a clear mathematical meaning through an accurate discussion of its terms. It holds for ideal observers (time-like smooth non-intersecting curves), but not for real, spatially extended observers. Analogous results hold for gauge fields. The difference between gravitation and the other fundamental interactions comes from their distinct roles in the equation of force. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0212034v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0212034v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 December, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2002. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX, 18 pages, no figures, to appear in Foundations of Physics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Found.Phys. 33 (2003) 545-575 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0207044">arXiv:gr-qc/0207044</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0207044">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0207044">ps</a>, <a href="https://arxiv.org/format/gr-qc/0207044">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Spacetime algebraic skeleton </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barbosa%2C+A+L">A. L. Barbosa</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0207044v2-abstract-short" style="display: inline;"> The cosmological constant Lambda, which has seemingly dominated the primaeval Universe evolution and to which recent data attribute a significant present-time value, is shown to have an algebraic content: it is essentially an eigenvalue of a Casimir invariant of the Lorentz group which acts on every tangent space. This is found in the context of de Sitter spacetimes but, as every spacetime is a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0207044v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0207044v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0207044v2-abstract-full" style="display: none;"> The cosmological constant Lambda, which has seemingly dominated the primaeval Universe evolution and to which recent data attribute a significant present-time value, is shown to have an algebraic content: it is essentially an eigenvalue of a Casimir invariant of the Lorentz group which acts on every tangent space. This is found in the context of de Sitter spacetimes but, as every spacetime is a 4-manifold with Minkowski tangent spaces, the result suggests the existence of a "skeleton" algebraic structure underlying the geometry of general physical spacetimes. Different spacetimes come from the "fleshening" of that structure by different tetrad fields. Tetrad fields, which provide the interface between spacetime proper and its tangent spaces, exhibit to the most the fundamental role of the Lorentz group in Riemannian spacetimes, a role which is obscured in the more usual metric formalism. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0207044v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0207044v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 July, 2002; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 July, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2002. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0203079">arXiv:gr-qc/0203079</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0203079">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0203079">ps</a>, <a href="https://arxiv.org/format/gr-qc/0203079">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> On the pre-nucleosynthesis cosmological period </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Gariel%2C+J">J. Gariel</a>, <a href="/search/gr-qc?searchtype=author&query=Marcilhacy%2C+G">G. Marcilhacy</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0203079v1-abstract-short" style="display: inline;"> Physics, as known from our local, around--earth experience, meets some of its applicability limits at the time just preceding the period of primeval nucleosynthesis. Attention is focussed here on the effects of the nucleon size. Radiation--belonging nucleons are found to produce an extremely high pressure at kT of the order of some tens or hundreds of MeV. Quark deconfinement at higher energies… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0203079v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0203079v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0203079v1-abstract-full" style="display: none;"> Physics, as known from our local, around--earth experience, meets some of its applicability limits at the time just preceding the period of primeval nucleosynthesis. Attention is focussed here on the effects of the nucleon size. Radiation--belonging nucleons are found to produce an extremely high pressure at kT of the order of some tens or hundreds of MeV. Quark deconfinement at higher energies would not change the results. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0203079v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0203079v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 March, 2002; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2002. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">standard LateX, 28 pages (no figures)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> IFT-P 018/2002 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/math-ph/0107021">arXiv:math-ph/0107021</a> <span> [<a href="https://arxiv.org/pdf/math-ph/0107021">pdf</a>, <a href="https://arxiv.org/ps/math-ph/0107021">ps</a>, <a href="https://arxiv.org/format/math-ph/0107021">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mathematical Physics">math-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Enlarged geometries of gauge bundles </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barbosa%2C+A+L">A. L. Barbosa</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="math-ph/0107021v1-abstract-short" style="display: inline;"> The geometrical picture of gauge theories must be enlarged when a gauge potential ceases to behave like a connection, as it does in electroweak interactions. When the gauge group has dimension four, the vector space isomorphism between spacetime and the gauge algebra is realized by a tetrad-like field. The object measuring the deviation from a strict bundle structure has the formal behavior of a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('math-ph/0107021v1-abstract-full').style.display = 'inline'; document.getElementById('math-ph/0107021v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="math-ph/0107021v1-abstract-full" style="display: none;"> The geometrical picture of gauge theories must be enlarged when a gauge potential ceases to behave like a connection, as it does in electroweak interactions. When the gauge group has dimension four, the vector space isomorphism between spacetime and the gauge algebra is realized by a tetrad-like field. The object measuring the deviation from a strict bundle structure has the formal behavior of a spacetime connection, of which the deformed gauge field-strength is the torsion. A generalized derivative emerges in terms of which the two Bianchi identities are formally recovered. Effects of gravitational type turn up. The dynamical equations obtained correspond to a broken gauge model on a curved spacetime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('math-ph/0107021v1-abstract-full').style.display = 'none'; document.getElementById('math-ph/0107021v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 July, 2001; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2001. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, revtex, no figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> GCR - 2000/08/01 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Int.J.Theor.Phys. 39 (2000) 2779-2796 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/0105068">arXiv:gr-qc/0105068</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/0105068">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/0105068">ps</a>, <a href="https://arxiv.org/format/gr-qc/0105068">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> Kinematics of a Spacetime with an Infinite Cosmological Constant </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barbosa%2C+A+L">A. L. Barbosa</a>, <a href="/search/gr-qc?searchtype=author&query=Calcada%2C+M">M. Calcada</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/0105068v2-abstract-short" style="display: inline;"> A solution of the sourceless Einstein's equation with an infinite value for the cosmological constant 螞is discussed by using Inonu-Wigner contractions of the de Sitter groups and spaces. When 螞--> infinity, spacetime becomes a four-dimensional cone, dual to Minkowski space by a spacetime inversion. This inversion relates the four-cone vertex to the infinity of Minkowski space, and the four-cone… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0105068v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/0105068v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/0105068v2-abstract-full" style="display: none;"> A solution of the sourceless Einstein's equation with an infinite value for the cosmological constant 螞is discussed by using Inonu-Wigner contractions of the de Sitter groups and spaces. When 螞--> infinity, spacetime becomes a four-dimensional cone, dual to Minkowski space by a spacetime inversion. This inversion relates the four-cone vertex to the infinity of Minkowski space, and the four-cone infinity to the Minkowski light-cone. The non-relativistic limit c --> infinity is further considered, the kinematical group in this case being a modified Galilei group in which the space and time translations are replaced by the non-relativistic limits of the corresponding proper conformal transformations. This group presents the same abstract Lie algebra as the Galilei group and can be named the conformal Galilei group. The results may be of interest to the early Universe Cosmology. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/0105068v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/0105068v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 2 December, 2002; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 May, 2001; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2001. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTex, 7 pages, no figures. Presentation changes, including a new Title. Version to appear in Found. Phys. Lett</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Found.Phys. 33 (2003) 613-624 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/9809061">arXiv:gr-qc/9809061</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/9809061">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/9809061">ps</a>, <a href="https://arxiv.org/format/gr-qc/9809061">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> A Second Poincare' Group </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/9809061v1-abstract-short" style="display: inline;"> Solutions of the sourceless Einstein's equation with weak and strong cosmological constants are discussed by using In枚n眉-Wigner contractions of the de Sitter groups and spaces. The more usual case corresponds to a weak cosmological-constant limit, in which the de Sitter groups are contracted to the Poincar茅 group, and the de Sitter spaces are reduced to the Minkowski space. In the strong cosmolo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9809061v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/9809061v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/9809061v1-abstract-full" style="display: none;"> Solutions of the sourceless Einstein's equation with weak and strong cosmological constants are discussed by using In枚n眉-Wigner contractions of the de Sitter groups and spaces. The more usual case corresponds to a weak cosmological-constant limit, in which the de Sitter groups are contracted to the Poincar茅 group, and the de Sitter spaces are reduced to the Minkowski space. In the strong cosmological-constant limit, however, the de Sitter groups are contracted to another group which has the same abstract Lie algebra of the Poincar茅 group, and the de Sitter spaces are reduced to a 4-dimensional cone-space of infinite scalar curvature, but vanishing Riemann and Ricci curvature tensors. In such space, the special conformal transformations act transitively, and the equivalence between inertial frames is that of special relativity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9809061v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/9809061v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 September, 1998; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 1998. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX, 7 pages, no figures, contribution to "Topics in Theoretical Physics II: Festschrift for A. H. Zimerman"</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> IFT-P.046/98 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/9801100">arXiv:gr-qc/9801100</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/9801100">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/9801100">ps</a>, <a href="https://arxiv.org/format/gr-qc/9801100">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0264-9381/16/2/013">10.1088/0264-9381/16/2/013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Non-Relativistic Spacetimes with Cosmological Constant </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Barbosa%2C+A+L">A. L. Barbosa</a>, <a href="/search/gr-qc?searchtype=author&query=Crispino%2C+L+C+B">L. C. B. Crispino</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/9801100v2-abstract-short" style="display: inline;"> Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of Einstein's equations with a cosmological constant, reduce in the non-relativistic limit to Newton-Hooke spacetimes, which are non-metric homogeneous spacetimes with no… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9801100v2-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/9801100v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/9801100v2-abstract-full" style="display: none;"> Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of Einstein's equations with a cosmological constant, reduce in the non-relativistic limit to Newton-Hooke spacetimes, which are non-metric homogeneous spacetimes with non-vanishing curvature. The whole non-relativistic kinematics would then be modified, with possible consequences to cosmology, and in particular to the missing-mass problem. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9801100v2-abstract-full').style.display = 'none'; document.getElementById('gr-qc/9801100v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 January, 1999; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 January, 1998; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 1998. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, RevTeX, no figures, major changes in the presentation which includes a new title and a whole new emphasis, version to appear in Clas. Quant. Grav</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> IFT-P.001/99 </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Class.Quant.Grav. 16 (1999) 495-506 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/9610068">arXiv:gr-qc/9610068</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/9610068">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/9610068">ps</a>, <a href="https://arxiv.org/format/gr-qc/9610068">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> The Case for a Gravitational de Sitter Gauge Theory </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Pereira%2C+J+G">J. G. Pereira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/9610068v1-abstract-short" style="display: inline;"> With the exception of gravitation, the known fundamental interactions of Nature are mediated by gauge fields. A comparison of the candidate groups for a gauge theory possibly describing gravitation favours the Poincar茅 group as the obvious choice. This theory gives Einstein's equations in a particular case, and Newton's law in the static non-relativistic limit, being seemingly sound at the class… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9610068v1-abstract-full').style.display = 'inline'; document.getElementById('gr-qc/9610068v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/9610068v1-abstract-full" style="display: none;"> With the exception of gravitation, the known fundamental interactions of Nature are mediated by gauge fields. A comparison of the candidate groups for a gauge theory possibly describing gravitation favours the Poincar茅 group as the obvious choice. This theory gives Einstein's equations in a particular case, and Newton's law in the static non-relativistic limit, being seemingly sound at the classical level. But it comes out that it is not quantizable. The usual procedure of adding counterterms to make it a consistent and renormalizable theory leads to two possible theories, one for each of the two de Sitter groups, SO(4,1) and SO(3,2). The consequences of changing from the Poincar茅 to the de Sitter group, as well as the positive aspects, perspectives and drawbacks of the resulting theory are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9610068v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/9610068v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 October, 1996; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 1996. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, standard latex, no figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> IFT-P.052/95 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/gr-qc/9404018">arXiv:gr-qc/9404018</a> <span> [<a href="https://arxiv.org/pdf/gr-qc/9404018">pdf</a>, <a href="https://arxiv.org/ps/gr-qc/9404018">ps</a>, <a href="https://arxiv.org/format/gr-qc/9404018">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.50.2645">10.1103/PhysRevD.50.2645 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fermion Helicity Flip in Weak Gravitational Fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/gr-qc?searchtype=author&query=Aldrovandi%2C+R">R. Aldrovandi</a>, <a href="/search/gr-qc?searchtype=author&query=Matsas%2C+G+E+A">G. E. A. Matsas</a>, <a href="/search/gr-qc?searchtype=author&query=Novaes%2C+S+F">S. F. Novaes</a>, <a href="/search/gr-qc?searchtype=author&query=Spehler%2C+D">D. Spehler</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="gr-qc/9404018v1-abstract-short" style="display: inline;"> The helicity flip of a spin-${\textstyle \frac{1}{2}}$ Dirac particle interacting gravitationally with a scalar field is analyzed in the context of linearized quantum gravity. It is shown that massive fermions may have their helicity flipped by gravity, in opposition to massless fermions which preserve their helicity. </span> <span class="abstract-full has-text-grey-dark mathjax" id="gr-qc/9404018v1-abstract-full" style="display: none;"> The helicity flip of a spin-${\textstyle \frac{1}{2}}$ Dirac particle interacting gravitationally with a scalar field is analyzed in the context of linearized quantum gravity. It is shown that massive fermions may have their helicity flipped by gravity, in opposition to massless fermions which preserve their helicity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('gr-qc/9404018v1-abstract-full').style.display = 'none'; document.getElementById('gr-qc/9404018v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 April, 1994; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 1994. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">RevTeX 3.0, 8 pages, 3 figures (available upon request), Preprint IFT-P.013/94</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys.Rev. D50 (1994) 2645-2647 </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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