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VERSION:2.0
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BEGIN:VEVENT
SUMMARY:Gravitational radiation in full general relativity with a non-nega
 tive cosmological constant
DTSTART:20231026T143000Z
DTEND:20231026T160000Z
DTSTAMP:20260914T061027Z
UID:e746de0f-0379-42c8-a2c0-fea1aeebb804
SEQUENCE:1
CREATED:20231020T131015Z
DESCRIPTION:ABSTRACT: A covariant\, gauge-invariant criterion for the exis
 tence\, or absence\, of gravitational radiation at infinity with non-negat
 ive cosmological constant (Lambda) is presented. For Lambda&gt\;0\, the fu
 ndamental idea is that the physical asymptotic properties are encoded in {
 I\,h\,D}\, where I is a three-dimensional manifold\, h is a representative
  of a conformal class of Riemannian metrics on I\, and D is a rank-2\, tra
 celess\, symmetric tensor field on I. Based on this\, and on the tidal nat
 ure of gravitational radiation\, a characterisation of gravitational radia
 tion at the conformal boundary is given using the asymptotic properties of
  the rescaled Bel-Robinson tensor. The asymptotically flat scenario is als
 o reviewed. In this case\, the new criterion is shown to be fully equivale
 nt to the classical one based on the news tensor. Also\, a new balance law
  at infinity is presented. (Based on joint work with José M. M. Senovilla
 ) 
LAST-MODIFIED:20231020T131015Z
LOCATION:Sala de Seminários do DF\,  Pavilhão de Física\, 2º piso
URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/gravitational-radiation-in
 -full-general-relativity-with-a-non-negative-cosmological-constant/
X-ALT-DESC;FMTTYPE=text/html:<p data-block-key="mf0dq"><b>ABSTRACT: </b></
 p><p data-block-key="5sj4c">A covariant\, gauge-invariant criterion for th
 e existence\, or absence\, of gravitational radiation at infinity with non
 -negative cosmological constant (Lambda) is presented. For Lambda&gt\;0\, 
 the fundamental idea is that the physical asymptotic properties are encode
 d in {I\,h\,D}\, where I is a three-dimensional manifold\, h is a represen
 tative of a conformal class of Riemannian metrics on I\, and D is a rank-2
 \, traceless\, symmetric tensor field on I. <br/><br/>Based on this\, and 
 on the tidal nature of gravitational radiation\, a characterisation of gra
 vitational radiation at the conformal boundary is given using the asymptot
 ic properties of the rescaled Bel-Robinson tensor. The asymptotically flat
  scenario is also reviewed. In this case\, the new criterion is shown to b
 e fully equivalent to the classical one based on the news tensor. Also\, a
  new balance law at infinity is presented. (Based on joint work with José
  M. M. Senovilla) </p>
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