Hybrid quantum-classical simulations of semiclassical gravity

Fuente: arXiv
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Main Authors: Fulgado-Claudio, Carlos, González-Cuadra, Daniel, Jiménez, Jose Beltrán, Bermudez, Alejandro
Format: Preprint
Published: 2026
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author Fulgado-Claudio, Carlos
González-Cuadra, Daniel
Jiménez, Jose Beltrán
Bermudez, Alejandro
author_facet Fulgado-Claudio, Carlos
González-Cuadra, Daniel
Jiménez, Jose Beltrán
Bermudez, Alejandro
contents We propose a hybrid quantum-classical algorithm for the simulation of real-time dynamics in interacting quantum field theories coupled to classical fields, focusing on the self-consistent estimation of semiclassical backreaction. By discretizing space and time, we construct an iterative protocol that simulates the Trotterized dynamics of the quantum fields subject to the dynamical classical fields. By estimating certain quantum expectation values through a set of projective measurements, we source the equations of motion of the classical fields, and solve them numerically to feed them forward to the quantum simulation in an iterative self-consistent loop. Semiclassical backreaction is relevant in various fields of physics, particularly in cosmology, where quantum matter fluctuations affect the gravitational field dynamics, and a controlled renormalization must be carefully considered to get a sensible continuum limit. We benchmark our algorithm in this context, focusing on scalar-tensor theories of modified gravity exhibiting a chameleon mechanism, such that a light classical scalar field driving cosmic acceleration becomes massive in high-density regions, effectively screening any possible yet unobserved fifth force. By focusing on numerically tractable regimes, we explicitly show the convergence and robustness of our algorithm when considering the continuum limit and the effect of quantum shot noise. Our work paves the way for future experiments exploring other non-tractable regimes, including non-perturbative interactions of the quantum fields and how these can change backreaction and the gravitational dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2603_06511
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Hybrid quantum-classical simulations of semiclassical gravity
Fulgado-Claudio, Carlos
González-Cuadra, Daniel
Jiménez, Jose Beltrán
Bermudez, Alejandro
General Relativity and Quantum Cosmology
High Energy Physics - Lattice
Quantum Physics
We propose a hybrid quantum-classical algorithm for the simulation of real-time dynamics in interacting quantum field theories coupled to classical fields, focusing on the self-consistent estimation of semiclassical backreaction. By discretizing space and time, we construct an iterative protocol that simulates the Trotterized dynamics of the quantum fields subject to the dynamical classical fields. By estimating certain quantum expectation values through a set of projective measurements, we source the equations of motion of the classical fields, and solve them numerically to feed them forward to the quantum simulation in an iterative self-consistent loop. Semiclassical backreaction is relevant in various fields of physics, particularly in cosmology, where quantum matter fluctuations affect the gravitational field dynamics, and a controlled renormalization must be carefully considered to get a sensible continuum limit. We benchmark our algorithm in this context, focusing on scalar-tensor theories of modified gravity exhibiting a chameleon mechanism, such that a light classical scalar field driving cosmic acceleration becomes massive in high-density regions, effectively screening any possible yet unobserved fifth force. By focusing on numerically tractable regimes, we explicitly show the convergence and robustness of our algorithm when considering the continuum limit and the effect of quantum shot noise. Our work paves the way for future experiments exploring other non-tractable regimes, including non-perturbative interactions of the quantum fields and how these can change backreaction and the gravitational dynamics.
title Hybrid quantum-classical simulations of semiclassical gravity
topic General Relativity and Quantum Cosmology
High Energy Physics - Lattice
Quantum Physics
url https://arxiv.org/abs/2603.06511