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The stability and convergence rate of Olver's collocation method for the numerical solution of Riemann-Hilbert problems (RHPs) is known to depend very sensitively on the particular choice of contours used as data of the RHP. By manually…

Numerical Analysis · Mathematics 2013-01-31 Georg Wechslberger , Folkmar Bornemann

The QCD at finite density is not well understood yet, where standard Monte Carlo simulation suffers from the sign problem. In order to overcome the sign problem, the method of Lefschetz thimble has been explored. Basically, the original…

High Energy Physics - Lattice · Physics 2018-04-18 Shoichiro Tsutsui , Takahiro M. Doi

Lattice Monte Carlo calculations of interacting systems on non-bipartite lattices exhibit an oscillatory imaginary phase known as the phase or sign problem, even at zero chemical potential. One method to alleviate the sign problem is to…

Strongly Correlated Electrons · Physics 2021-03-31 Jan-Lukas Wynen , Evan Berkowitz , Stefan Krieg , Thomas Luu , Johann Ostmeyer

We present a general technique for addressing sign problems that arise in Monte Carlo simulations of field theories. This method deforms the domain of the path integral to a manifold in complex field space that maximizes the average sign…

High Energy Physics - Lattice · Physics 2018-06-06 Andrei Alexandru , Paulo Bedaque , Henry Lamm , Scott Lawrence

We present a computational strategy for reducing the sign problem in the evaluation of high dimensional integrals with non-positive definite weights. The method involves stochastic sampling with a positive semidefinite weight that is…

Computational Physics · Physics 2009-11-10 A G Moreira , S A Baeurle , G H Fredrickson

A method is presented to tackle the sign problem in the simulations of systems having indefinite or complex-valued measures. In general, this new approach is shown to yield statistical errors smaller than the crude Monte Carlo using…

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

Projection of the Coulomb potential onto flat bands paves the way to design various interactions in the particle-hole and particle-particle channels. Here we pose the question if we can use this mapping to overcome the negative sign problem…

Strongly Correlated Electrons · Physics 2023-12-05 Maksim Ulybyshev , Anika Götz , Fakher Assaad

This work focuses on a parameter-free joint piecewise smooth image denoising and contour detection. Formulated as the minimization of a discrete Mumford-Shah functional and estimated via a theoretically grounded alternating minimization…

Image and Video Processing · Electrical Eng. & Systems 2023-02-01 Charles-Gérard Lucas , Barbara Pascal , Nelly Pustelnik , Patrice Abry

Sign problem in quantum Monte Carlo (QMC) simulation appears to be an extremely hard yet interesting problem. In this article, we present a pedagogical overview on the origin of the sign problem in various quantum Monte Carlo simulation…

Strongly Correlated Electrons · Physics 2023-10-27 Gaopei Pan , Zi Yang Meng

We study the heavy-dense limit of QCD on the lattice with heavy quarks at high density. The effective three dimensional theory has a sign problem which is alleviated by sign optimization where the path integration domain is deformed in…

High Energy Physics - Theory · Physics 2023-12-14 Gokce Basar , Joseph Marincel

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

Standard lattice fermion algorithms run into the well-known sign problem at real chemical potential. In this paper we investigate the possibility of using imaginary chemical potential, and argue that it has advantages over other methods,…

High Energy Physics - Lattice · Physics 2009-07-09 M. Alford , A. Kapustin , F. Wilczek

In this article, we explore the use of contour deformation for the numerical evaluation of Feynman integrals after sector decomposition. In existing codes, the contour of integration is determined heuristically for each phase-space point by…

High Energy Physics - Phenomenology · Physics 2026-02-16 Stephen Jones , Daniel Maître , Anton Olsson

The sign problem is a notorious problem, which occurs in Monte Carlo simulations of a system with a partition function whose integrand is not positive. One way to simulate such a system is to use the factorization method where one enforces…

High Energy Physics - Lattice · Physics 2012-11-08 Konstantinos N. Anagnostopoulos , Takehiro Azuma , Jun Nishimura

Monte Carlo studies of many quantum systems face exponentially severe signal-to-noise problems. We show that noise arising from complex phase fluctuations of observables can be reduced without introducing bias using path integral contour…

High Energy Physics - Lattice · Physics 2020-08-05 William Detmold , Gurtej Kanwar , Michael L. Wagman , Neill C. Warrington

Strongly correlated fermionic systems are of great interest in condensed matter physics and numerical methods are indispensable tools for their study. However, existing approaches such as exact diagonalization (ED) and stochastic quantum…

Strongly Correlated Electrons · Physics 2026-03-19 Finn L. Temmen , Martina Gisti , David J. Luitz , Thomas Luu , Johann Ostmeyer

We consider the offset-deconstruction problem: Given a polygonal shape Q with n vertices, can it be expressed, up to a tolerance \eps in Hausdorff distance, as the Minkowski sum of another polygonal shape P with a disk of fixed radius? If…

Computational Geometry · Computer Science 2011-09-13 Eric Berberich , Dan Halperin , Michael Kerber , Roza Pogalnikova

Hardware distortions (HWD) render drastic effects on the performance of communication systems. They are recently proven to bear asymmetric signatures; and hence can be efficiently mitigated using improper Gaussian signaling (IGS), thanks to…

Signal Processing · Electrical Eng. & Systems 2020-09-14 Sidrah Javed , Ahmed Elzanaty , Osama Amin , Basem Shihada , Mohamed-Slim Alouini

We present a new Monte Carlo algorithm for simulating quantum spin systems which is able to suppress the negative sign problem. This algorithm has only a linear complexity in the lattice size used for the simulation. A general description…

High Energy Physics - Lattice · Physics 2007-05-23 A. Galli

Ground state properties of the Hubbard model are of fundamental importance to understand the mechanism of unconventional superconductivity in the high-T_c cuprates and other materials. One of the most powerful numerical methods for strongly…

Strongly Correlated Electrons · Physics 2026-03-30 Jodie Roberts , Beau A. Thompson , R. Torsten Clay