Unitarity and quantum resolution of gravitational singularities

• URL: http://arxiv.org/abs/2205.15387v2
• Date: Wed, 6 Jul 2022 15:48:23 GMT
• Title: Unitarity and quantum resolution of gravitational singularities
• Authors: Steffen Gielen, Luc\'ia Men\'endez-Pidal
• Abstract summary: We show that unitarity for a clock that encounters a classical singularity at finite time implies quantum resolution, but for a clock that encounters future infinity at finite time leads to a quantum recollapse.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We explore the consequences of requiring that quantum theories of gravity be unitary, mostly focusing on simple cosmological models to illustrate the main points. We show that unitarity for a clock that encounters a classical singularity at finite time implies quantum singularity resolution, but for a clock that encounters future infinity at finite time leads to a quantum recollapse. We then find that our starting point - assuming the general covariance of general relativity - is actually incompatible with general quantum unitarity: singularity resolution in quantum gravity can always be engineered by choosing the right clock, or avoided by using a different one.

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