Relativity and decoherence of spacetime superpositions
- URL: http://arxiv.org/abs/2302.03259v1
- Date: Tue, 7 Feb 2023 05:10:52 GMT
- Title: Relativity and decoherence of spacetime superpositions
- Authors: Joshua Foo, Robert B. Mann, Magdalena Zych
- Abstract summary: In a theory of quantum gravity there exist quantum superpositions of semiclassical states of spacetime geometry.
In this paper we introduce a framework for describing such ''quantum superpositions of spacetime states''
We show that for states in which the superposed amplitudes differ by a coordinate transformation, it is always possible to re-express the scenario in terms of dynamics on a single, fixed background.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: It is univocally anticipated that in a theory of quantum gravity, there exist
quantum superpositions of semiclassical states of spacetime geometry. Such
states could arise for example, from a source mass in a superposition of
spatial configurations. In this paper we introduce a framework for describing
such ''quantum superpositions of spacetime states.'' We introduce the notion of
the relativity of spacetime superpositions, demonstrating that for states in
which the superposed amplitudes differ by a coordinate transformation, it is
always possible to re-express the scenario in terms of dynamics on a single,
fixed background. Our result unveils an inherent ambiguity in labelling such
superpositions as genuinely quantum-gravitational, which has been done
extensively in the literature, most notably with reference to recent proposals
to test gravitationally-induced entanglement. We apply our framework to the the
above mentioned scenarios looking at gravitationally-induced entanglement, the
problem of decoherence of gravitational sources, and clarify commonly
overlooked assumptions. In the context of decoherence of gravitational sources,
our result implies that the resulting decoherence is not fundamental, but
depends on the existence of external systems that define a relative set of
coordinates through which the notion of spatial superposition obtains physical
meaning.
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