Quantum coherent dynamics of quasiclassical spacetimes

• URL: http://arxiv.org/abs/2511.20759v2
• Date: Thu, 27 Nov 2025 19:44:21 GMT
• Title: Quantum coherent dynamics of quasiclassical spacetimes
• Authors: Sijia Wang, Achintya Sajeendran, Dong-han Yeom, Robert B. Mann, Joshua Foo,
• Abstract summary: Hamiltonian formalism for gravitational dynamics generates time evolution of the spacetime with respect to a clock at infinity.<n>We apply our framework to the problem of black hole evaporation, providing a hint at how unitarity may be preserved.
• Score: 5.067519999094637
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: In a wide range of quantum gravity theories, quasiclassical geometries, which are solutions to the Einstein field equations approximately, are described by "coherent states." Here we propose a Hamiltonian formalism for gravitational dynamics with respect to this coherent state basis, which generates time evolution of the spacetime with respect to a clock at infinity. Since the coherent states are not orthogonal, an initial quasiclassical geometry is dynamically driven into a superposition of different amplitudes. Our framework provides a dynamical mechanism for tunneling between geometries that is ubiquitous in a number of approaches to quantum gravity, from loop quantum gravity to the Euclidean path integral. We apply our framework to the problem of black hole evaporation, providing a hint at how unitarity may be preserved with the inclusion of quantum corrections to the semiclassical evolution of the black hole.

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