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SUMMARY:Should we take into account nontrivial spacetime topology\, change
 s of metric signature and similar hypothetical phenomena when quantizing g
 ravity?
DTSTART;VALUE=DATE-TIME:20241023T070000Z
DTEND;VALUE=DATE-TIME:20241023T071500Z
DTSTAMP;VALUE=DATE-TIME:20260314T050507Z
UID:indico-contribution-4156@cern.ch
DESCRIPTION:Speakers: Tatyana Shestakova (Department of Theoretical and Co
 mputational Physics\, Southern Federal University)\nThe founders of quantu
 m geometrodynamics assumed that spacetime may have nontrivial topology: Jo
 hn Wheeler suggested the idea of spacetime foam\; Stephen Hawking wrote th
 at one would expect that quantum gravity would allow all possible topologi
 es of spacetime. Later\, A. D. Sakharov put forward yet more exotic hypoth
 esis that metric signature may change. Then the question arises\, do we re
 ally need to take into account all these hypothetical phenomena when quant
 izing gravity? Since observational data witnesses for an open flat univers
 e\, it is possible\, in principle\, to construct a theory of perturbations
  of gravitational and matter fields. However\, it would not be a full quan
 tum theory of gravity. I shall argue that the assumption about nontrivial 
 spacetime topology\, etc. leads to a new description of the Universe in wh
 ich periods of unitary evolution give place to non-unitary changes of the 
 Universe state. It gives a hope that it may shed light on an origin of irr
 eversibility.\n\nhttps://indico.particle.mephi.ru/event/436/contributions/
 4156/
LOCATION: Moskvorechye 1
URL:https://indico.particle.mephi.ru/event/436/contributions/4156/
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