Dynamics of discrete spacetimes with Quantum-enhanced Markov Chain Monte Carlo

Fuente: arXiv
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Main Authors: Ferguson, Stuart, Nasiri, Arad, Wallden, Petros
Format: Preprint
Published: 2025
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author Ferguson, Stuart
Nasiri, Arad
Wallden, Petros
author_facet Ferguson, Stuart
Nasiri, Arad
Wallden, Petros
contents Quantum algorithms offer the potential for significant computational advantages; however, in many cases, it remains unclear how these advantages can be practically realized. Causal Set Theory is a discrete, Lorentz-invariant approach to quantum gravity which may be well positioned to benefit from quantum computing. In this work, we introduce a quantum algorithm that investigates the dynamics of causal sets by sampling the space of causal sets, improving on classical methods. Our approach builds on the quantum-enhanced Markov chain Monte Carlo technique developed by Layden et al. [Nature 619, 282 (2023)], adapting it to sample from the constrained spaces required for application. This is done by adding a constraint term to the Hamiltonian of the system. A qubit Hamiltonian representing the Benincasa-Dowker action (the causal set equivalent of the Einstein-Hilbert action) is also derived and used in the algorithm as the problem Hamiltonian. We achieve a super-quadratic quantum scaling advantage and, under some conditions, demonstrate a greater potential compared to classical approaches than previously observed in unconstrained QeMCMC implementations.
format Preprint
id arxiv_https___arxiv_org_abs_2506_19538
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamics of discrete spacetimes with Quantum-enhanced Markov Chain Monte Carlo
Ferguson, Stuart
Nasiri, Arad
Wallden, Petros
Quantum Physics
General Relativity and Quantum Cosmology
Computational Physics
Quantum algorithms offer the potential for significant computational advantages; however, in many cases, it remains unclear how these advantages can be practically realized. Causal Set Theory is a discrete, Lorentz-invariant approach to quantum gravity which may be well positioned to benefit from quantum computing. In this work, we introduce a quantum algorithm that investigates the dynamics of causal sets by sampling the space of causal sets, improving on classical methods. Our approach builds on the quantum-enhanced Markov chain Monte Carlo technique developed by Layden et al. [Nature 619, 282 (2023)], adapting it to sample from the constrained spaces required for application. This is done by adding a constraint term to the Hamiltonian of the system. A qubit Hamiltonian representing the Benincasa-Dowker action (the causal set equivalent of the Einstein-Hilbert action) is also derived and used in the algorithm as the problem Hamiltonian. We achieve a super-quadratic quantum scaling advantage and, under some conditions, demonstrate a greater potential compared to classical approaches than previously observed in unconstrained QeMCMC implementations.
title Dynamics of discrete spacetimes with Quantum-enhanced Markov Chain Monte Carlo
topic Quantum Physics
General Relativity and Quantum Cosmology
Computational Physics
url https://arxiv.org/abs/2506.19538