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The numerical sign problem has long been a major obstacle to first-principles calculations in various important fields of physics. We report that the recently proposed algorithm, tempered Lefschetz thimble method (TLTM), and its worldvolume…

High Energy Physics - Lattice · Physics 2021-11-30 Masafumi Fukuma , Nobuyuki Matsumoto

We consider the method of mappings for performing shape optimization for unsteady fluid-structure interaction (FSI) problems. In this work, we focus on the numerical implementation. We model the optimization problem such that it takes…

Optimization and Control · Mathematics 2024-06-21 Johannes Haubner , Michael Ulbrich

Symbolic regression with polynomial neural networks and polynomial neural ordinary differential equations (ODEs) are two recent and powerful approaches for equation recovery of many science and engineering problems. However, these methods…

Machine Learning · Computer Science 2023-08-28 Colby Fronk , Jaewoong Yun , Prashant Singh , Linda Petzold

Some notable systems, such as room-temperature superconductors and materials for controlled nuclear fusion, require an accurate description of finite-temperature quantum matter. Stochastic path integral methods are finite-temperature and…

Strongly Correlated Electrons · Physics 2026-04-06 Ingvars Vitenburgs , Jarvist Moore Frost

Many imaging problems require solving an inverse problem that is ill-conditioned or ill-posed. Imaging methods typically address this difficulty by regularising the estimation problem to make it well-posed. This often requires setting the…

Methodology · Statistics 2020-08-17 Ana F. Vidal , Valentin De Bortoli , Marcelo Pereyra , Alain Durmus

We discuss the Fermion sign problem and, by examining a very general Hubbard-Stratonovich (HS) transformation, argue that the sign problem cannot be solved with such methods. We propose a different kind of transformation which, while not…

Condensed Matter · Physics 2011-08-11 Ghassan George Batrouni , Philippe de Forcrand

We apply the path optimization method to a QCD effective model with the Polyakov loop at finite density to circumvent the model sign problem. The Polyakov-loop extended Nambu--Jona-Lasinio model is employed as the typical QCD effective…

High Energy Physics - Phenomenology · Physics 2019-01-30 Kouji Kashiwa , Yuto Mori , Akira Ohnishi

We present a strategy to alleviate the sign problem in continuous-time quantum Monte Carlo (CTQMC) simulations of the dynamical-mean-field-theory (DMFT) equations for the spin-orbit-coupled multiorbital Hubbard model. We first identify the…

Strongly Correlated Electrons · Physics 2020-01-22 Aaram J. Kim , Philipp Werner , Roser Valentí

A simple similarity has been proposed for kinetic (e.g., particle-in-cell) simulations of plasma transport that can effectively address the longstanding challenge of reconciling the tiny Debye length with the vast system size. This applies…

Plasma Physics · Physics 2025-04-17 Yanzeng Zhang , Haotian Mao , Yuzhi Li , Xian-Zhu Tang

In this paper, we consider the weighted graph matching problem with partially disclosed correspondences between a number of anchor nodes. Our construction exploits recently introduced node signatures based on graph Laplacians, namely the…

Computer Vision and Pattern Recognition · Computer Science 2018-04-12 Nan Hu , Raif M. Rustamov , Leonidas Guibas

We construct a lattice field theory method for computing the real-time dynamics of spin systems in a thermal bath. This is done by building on previous work of Takano with Schwinger-Keldysh and functional differentiation techniques. We…

Quantum Physics · Physics 2023-10-31 Neill C. Warrington

Problems with sign-changing coefficients occur, for instance, in the study of transmission problems with metamaterials. In this work, we present and analyze a generalized finite element method in the spirit of the Localized Orthogonal…

Numerical Analysis · Mathematics 2020-08-28 Théophile Chaumont-Frelet , Barbara Verfürth

We introduce the feedforward neural network to attack the sign problem via the path optimization method. The variables of integration is complexified and the integration path is optimized in the complexified space by minimizing the cost…

High Energy Physics - Lattice · Physics 2019-12-06 Yuto Mori , Kouji Kashiwa , Akira Ohnishi

We state a combinatorial optimization problem whose feasible solutions define both a decomposition and a node labeling of a given graph. This problem offers a common mathematical abstraction of seemingly unrelated computer vision tasks,…

Computer Vision and Pattern Recognition · Computer Science 2017-02-22 Evgeny Levinkov , Jonas Uhrig , Siyu Tang , Mohamed Omran , Eldar Insafutdinov , Alexander Kirillov , Carsten Rother , Thomas Brox , Bernt Schiele , Bjoern Andres

A novel unified approach to jointly optimize structural design parameters, actuator and sensor precision and controller parameters is presented in this paper. The joint optimization problem is posed as a covariance control problem, where…

Systems and Control · Electrical Eng. & Systems 2021-06-02 Raman Goyal , Manoranjan Majji , Robert E. Skelton

Towards a solution to the sign problem in the simulations of systems having indefinite or complex-valued measures, we propose a new approach which yields statistical errors smaller than the crude Monte Carlo using absolute values of the…

High Energy Physics - Lattice · Physics 2008-11-26 T D Kieu , C J Griffin

Numerical simulations of lattice quantum field theories whose continuum counterparts possess classical solutions with non-trivial topology face a severe critical slowing down as the continuum limit is approached. Standard Monte-Carlo…

High Energy Physics - Lattice · Physics 2018-08-01 Claudio Bonati , Massimo D'Elia

At nonzero quark chemical potential dynamical lattice simulations of QCD are hindered by the sign problem caused by the complex fermion determinant. The severity of the sign problem can be assessed by the average phase of the fermion…

High Energy Physics - Lattice · Physics 2011-05-27 Jacques Bloch , Tilo Wettig

Simulations of supersymmetric models on the lattice with (spontaneously) broken supersymmetry suffer from a fermion sign problem related to the vanishing of the Witten index. We propose a novel approach which solves this problem in low…

High Energy Physics - Lattice · Physics 2011-04-04 David Baumgartner , Urs Wenger

In this article, I provide significant mathematical evidence in support of the existence of short-time approximations of any polynomial order for the computation of density matrices of physical systems described by arbitrarily smooth and…

Mathematical Physics · Physics 2009-11-10 Cristian Predescu