Observer Time from Causality in Perturbative Quantum Gravity

Fuente: arXiv
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Main Author: Sivaramakrishnan, Allic
Format: Preprint
Published: 2025
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author Sivaramakrishnan, Allic
author_facet Sivaramakrishnan, Allic
contents It is unclear whether an observable notion of time exists in quantum gravity even in principle because spacetime itself fluctuates. We propose a form of observable time in perturbative quantum gravity. First, we define an elapsed proper time in curved space using intersections of worldlines and future light cones. Here, time arises from causality via the dependence on light cones. We then propose that performing the gravitational path integral describes quantum gravity corrections to this notion of proper time at all orders in $G_N$. Using this prescription, we compute the leading quantum gravity corrections to two-point correlation functions of elapsed time. We find that the commutators can be nonzero, showing this notion of time is a quantum operator in quantum gravity.
format Preprint
id arxiv_https___arxiv_org_abs_2506_16109
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Observer Time from Causality in Perturbative Quantum Gravity
Sivaramakrishnan, Allic
High Energy Physics - Theory
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
It is unclear whether an observable notion of time exists in quantum gravity even in principle because spacetime itself fluctuates. We propose a form of observable time in perturbative quantum gravity. First, we define an elapsed proper time in curved space using intersections of worldlines and future light cones. Here, time arises from causality via the dependence on light cones. We then propose that performing the gravitational path integral describes quantum gravity corrections to this notion of proper time at all orders in $G_N$. Using this prescription, we compute the leading quantum gravity corrections to two-point correlation functions of elapsed time. We find that the commutators can be nonzero, showing this notion of time is a quantum operator in quantum gravity.
title Observer Time from Causality in Perturbative Quantum Gravity
topic High Energy Physics - Theory
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2506.16109