Schedule May 25, 2012
Would Schrodinger's Cat Have Collapsed Its Own Wavefunction? A Search for Gravitational Decoherence
Cisco (David) Gooding (Univ BC)

Despite the lack of a complete theory of quantum gravity, one can still extract information from simple general relativistic systems for which approximate quantum treatments can be given. This work focuses on a minisuperspace model of a spherical perfect fluid shell, and we consider whether or not this idealized system can exhibit the phenomenon known as "gravitational decoherence". Originally suggested by Feynman in the '60s and notoriously advocated by Roger Penrose since the '80s, gravitational decoherence is claimed to result from taking the effects of spacetime curvature into account when forming quantum superpositions. The model considered here is a generalization of the dust shell model that Kraus and Wilczek used in the mid 90s in an attempt to correct the standard Hawking radiation to include gravitational back-reaction. For our purposes, the spherical fluid shell will be a self-consistent interferometer, designed for splitting apart quantum wave-packets to create "Schrodinger cat" states. The split-apart wave-packets are then brought back together to interfere with themselves, and examined for traces of decoherence. If present, this type of decoherence provides a mechanism for the universe to effectively "observe" itself, i.e., for Schrodinger's cat to "collapse" its own wavefunction.

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