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In Euclidean path integrals, quantum mechanical tunneling amplitudes are associated with instanton configurations. We explain how tunneling amplitudes are encoded in real-time Feynman path integrals. The essential steps are borrowed from…

High Energy Physics - Theory · Physics 2014-08-20 Aleksey Cherman , Mithat Unsal

We develop a mathematically well-defined path integral formalism for general symplectic manifolds. We argue that in order to make a path integral quantization covariant under general coordinate transformations on the phase space and involve…

Quantum Physics · Physics 2009-10-31 Sergei V. Shabanov , John R. Klauder

This paper provides a pedagogical introduction to the quantum mechanical path integral and its use in proving index theorems in geometry, specifically the Gauss-Bonnet-Chern theorem and Lefschetz fixed point theorem. It also touches on some…

Mathematical Physics · Physics 2015-09-11 Mark van Loon

One of the main challenges in simulations on Lefschetz thimbles is the computation of the relative weights of contributing thimbles. In this paper we propose a solution to that problem by means of computing those weights using a reweighting…

Monte Carlo studies involving real time dynamics are severely restricted by the sign problem that emerges from highly oscillatory phase of the path integral. In this letter, we present a new method to compute real time quantities on the…

High Energy Physics - Lattice · Physics 2016-08-24 Andrei Alexandru , Gokce Basar , Paulo F. Bedaque , Sohan Vartak , Neill C. Warrington

Although the path-integral formalism is known to be equivalent to conventional quantum mechanics, it is not generally obvious how to implement path-based calculations for multi-qubit entangled states. Whether one takes the formal view of…

Quantum Physics · Physics 2022-06-08 Narayani Tyagi , Ken Wharton

In recent years efficient algorithms have been developed for the numerical computation of relativistic single-particle path integrals in quantum field theory. Here, we adapt this "worldline Monte Carlo" approach to the standard problem of…

A simple and efficient method for quantum Monte Carlo simulation is presented, based on discretization of the action in the path integral, and a Gaussian averaging of the potential, which works well e.g. with the Coulomb potential.

Computational Physics · Physics 2007-05-23 Jan Myrheim

Relativistic generalization of Path Integral Monte-Carlo method has been proposed and some possible applications have been discussed.

Quantum Physics · Physics 2014-11-03 Oleg Pavlovsky , Alexander Ivanov , Alexander Novoselov

A novel method for simulating the statistical mechanics of molecular systems in which both nuclear and electronic degrees of freedom are treated quantum mechanically is presented. The scheme combines a path integral description of the…

Computational Physics · Physics 2009-10-31 Ruben O. Weht , Jorge Kohanoff , Dario A. Estrin , Charusita Chakravarty

The cavity method is a well established technique for solving classical spin models on sparse random graphs (mean-field models with finite connectivity). Laumann et al. [arXiv:0706.4391] proposed recently an extension of this method to…

Statistical Mechanics · Physics 2009-11-13 Florent Krzakala , Alberto Rosso , Guilhem Semerjian , Francesco Zamponi

We describe how to construct and compute unambiguously path integrals for particles moving in a curved space, and how these path integrals can be used to calculate Feynman graphs and effective actions for various quantum field theories with…

High Energy Physics - Theory · Physics 2007-05-23 Fiorenzo Bastianelli

The concept of Lefschetz thimble decomposition is one of the most promising possible modifications of Quantum Monte Carlo (QMC) algorithms aimed at alleviating the sign problem which appears in many interesting physical situations, e.g. in…

Strongly Correlated Electrons · Physics 2017-12-07 M. V. Ulybyshev , S. N. Valgushev

Lefschetz thimbles have been proposed recently as a possible solution to the complex action problem (sign problem) in Monte Carlo simulations. Here we discuss pure abelian gauge theory with a complex coupling $\beta$ and apply the concept…

High Energy Physics - Lattice · Physics 2020-01-28 Jan M. Pawlowski , Manuel Scherzer , Christian Schmidt , Felix P. G. Ziegler , Felix Ziesché

A path integral formalism has been proposed recently for non-equilibrium statistical physics applications by the author. In this contribution we outline an efficient method for its numerical evaluation. The method used is based on the…

Numerical Analysis · Computer Science 2016-06-29 Richard Kleeman

Quantum cosmology aims at elucidating the beginning of our Universe. Back in early 80's, Vilenkin and Hartle-Hawking put forward the "tunneling from nothing" and "no boundary" proposals. Recently there has been renewed interest in this…

General Relativity and Quantum Cosmology · Physics 2025-04-08 Chien-Yu Chou , Jun Nishimura

Although the Hamiltonian formalism is so far favored for quantum computation of lattice gauge theory, the path integral formalism would never be useless. The advantages of the path integral formalism are the knowledge and experience…

Quantum Physics · Physics 2022-05-12 Arata Yamamoto

Applicability of Feynman path integral approach to numerical simulations of quantum dynamics in real time domain is examined. Coherent quantum dynamics is demonstrated with one dimensional test cases (quantum dot models) and performance of…

Computational Physics · Physics 2023-07-19 Ilkka Ruokosenmäki , Tapio T. Rantala

Path integrals are a central tool when it comes to describing quantum or thermal fluctuations of particles or fields. Their success dates back to Feynman who showed how to use them within the framework of quantum mechanics. Since then, path…

Statistical Mechanics · Physics 2022-08-31 Leticia F. Cugliandolo , Vivien Lecomte , Frédéric Van Wijland

We have developed a numerically exact approach to compute real-time path integral expressions for quantum transport problems out of equilibrium. The scheme is based on a deterministic iterative summation of the path integral (ISPI) for the…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 S. Weiss , R. Hützen , D. Becker , J. Eckel , R. Egger , M. Thorwart