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SUMMARY:Bra-Ket Wormholes and the Wigner Distribution - Joshua Kames-King\
 , EPFL
DTSTART:20250501T120000Z
DTEND:20250501T130000Z
UID:TALK229990@talks.cam.ac.uk
CONTACT:122734
DESCRIPTION:Based on 2408.08351 and some work in progress. We study a mode
 l for the initial state of the universe based on a gravitational path inte
 gral that includes connected geometries which simultaneously produce bra a
 nd ket of the wave function. We argue that a natural object to describe th
 is state is the Wigner distribution\, which is a function on a classical p
 hase space obtained by a certain integral transform of the density matrix.
  We work with Lorentzian de Sitter Jackiw-Teitelboim gravity in which we f
 ind semiclassical saddle-points for pure gravity\, as well as when we incl
 ude matter components such as a CFT and a classical inflaton field. We als
 o discuss different choices of fixing time reparametrizations. In the regi
 me of large universes our connected geometry dominates over the Hartle-Haw
 king saddle and gives a distribution that has a meaningful probabilistic i
 nterpretation for local observables. It does not\, however\, give a normal
 izable probability measure on the entire phase space of the theory.
LOCATION:Potter Room (B1.19)
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