Efficient evaluation of real-time path integrals

Fuente: arXiv
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Hauptverfasser: Feldbrugge, Job, Jones, Joshua Y. L.
Format: Preprint
Veröffentlicht: 2025
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author Feldbrugge, Job
Jones, Joshua Y. L.
author_facet Feldbrugge, Job
Jones, Joshua Y. L.
contents The Feynman path integral has revolutionized modern approaches to quantum physics. Although the path integral formalism has proven very successful and spawned several approximation schemes, the direct evaluation of real-time path integrals is still extremely expensive and numerically delicate due to its high-dimensional and oscillatory nature. We propose an efficient method for the numerical evaluation of the real-time world-line path integral for theories where the potential is dominated by a quadratic at infinity. This is done by rewriting the high-dimensional oscillatory integral in terms of a series of low-dimensional oscillatory integrals, that we efficiently evaluate with Picard-Lefschetz theory or approximate with the eikonal approximation. Subsequently, these integrals are stitched together with a series of fast Fourier transformations to recover the lattice regularized Feynman path integral. Our method directly applies to problems in quantum mechanics, the word-line quantization of quantum field theory, and quantum gravity.
format Preprint
id arxiv_https___arxiv_org_abs_2501_16323
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Efficient evaluation of real-time path integrals
Feldbrugge, Job
Jones, Joshua Y. L.
Quantum Physics
General Relativity and Quantum Cosmology
The Feynman path integral has revolutionized modern approaches to quantum physics. Although the path integral formalism has proven very successful and spawned several approximation schemes, the direct evaluation of real-time path integrals is still extremely expensive and numerically delicate due to its high-dimensional and oscillatory nature. We propose an efficient method for the numerical evaluation of the real-time world-line path integral for theories where the potential is dominated by a quadratic at infinity. This is done by rewriting the high-dimensional oscillatory integral in terms of a series of low-dimensional oscillatory integrals, that we efficiently evaluate with Picard-Lefschetz theory or approximate with the eikonal approximation. Subsequently, these integrals are stitched together with a series of fast Fourier transformations to recover the lattice regularized Feynman path integral. Our method directly applies to problems in quantum mechanics, the word-line quantization of quantum field theory, and quantum gravity.
title Efficient evaluation of real-time path integrals
topic Quantum Physics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2501.16323