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Related papers: On the Sign Problem of the Fermionic Shadow Wave F…

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Many fascinating systems suffer from a severe (complex action) sign problem preventing us from calculating them with Markov Chain Monte Carlo simulations. One promising method to alleviate the sign problem is the transformation of the…

Strongly Correlated Electrons · Physics 2022-11-18 Marcel Rodekamp , Christoph Gäntgen

Fermionic Monte Carlo calculations with continuous auxiliary fields often encounter infinite variance problem from fermionic observables. This issue renders the estimation of observables unreliable, even with an infinite number of samples.…

High Energy Physics - Lattice · Physics 2023-11-28 Hyunwoo Oh , Andrei Alexandru , Paulo F. Bedaque , Andrea Carosso

As an intrinsically-unbiased approach, quantum Monte Carlo (QMC) is of vital importance in understanding correlated phases of matter. Unfortunately, it often suffers notorious sign problem when simulating interacting fermion models. Here,…

Strongly Correlated Electrons · Physics 2022-11-03 Zi-Xiang Li , Zhou-Quan Wan , Hong Yao

In this talk we show how the sign problem, occurring in dynamical simulations of random matrices at nonzero chemical potential, can be avoided by judiciously combining matrices into subsets. One can prove that these subsets have real and…

High Energy Physics - Lattice · Physics 2011-11-22 Jacques C. R. Bloch

We present a quantum Monte Carlo method which allows calculations on many-fermion systems at finite temperatures without any sign decay. This enables simulations of the grand-canonical ensemble at large system sizes and low temperatures.…

Condensed Matter · Physics 2009-10-31 Shiwei Zhang

We demonstrate that extending the Shadow Wave Function to fermionic systems facilitates to accurately calculate strongly-correlated multi-reference systems such as the stretched H2 molecule. This development considerably extends the scope…

Computational Physics · Physics 2015-09-14 F. Calcavecchia , T. D. Kühne

The triangular lattice antiferromagnet with $S=1/2$ spins and nearest neighbor interactions is known to have long-range antiferromagnetic order, with nearest-neighbor spins at an angle of 120 degrees. Numerical studies of quantum phases…

Strongly Correlated Electrons · Physics 2025-09-09 Leyna Shackleton , Subir Sachdev

In the fermion loop formulation the contributions to the partition function naturally separate into topological equivalence classes with a definite sign. This separation forms the basis for an efficient fermion simulation algorithm using a…

High Energy Physics - Lattice · Physics 2015-09-14 David Baumgartner , Urs Wenger

The short-range modes of the fermionic determinant can be absorbed in the gauge action using the loop expansion. The coefficients of this expansion and the zeroes of the polynomial approximating the remainder can be optimized by a simple,…

High Energy Physics - Lattice · Physics 2009-10-31 Ph. de Forcrand

The conventional tensor-network states employ real-space product states as reference wave functions. Here, we propose a many-variable variational Monte Carlo (mVMC) method combined with tensor networks by taking advantages of both to study…

Strongly Correlated Electrons · Physics 2017-08-09 Hui-Hai Zhao , Kota Ido , Satoshi Morita , Masatoshi Imada

We demonstrate, by considering the triangular lattice spin-1/2 Heisenberg model, that Monte Carlo sampling of skeleton Feynman diagrams within the fermionization framework offers a universal first-principles tool for strongly correlated…

Strongly Correlated Electrons · Physics 2013-04-09 S. A. Kulagin , N. Prokof'ev , O. A. Starykh , B. Svistunov , C. N. Varney

We use a variational Monte Carlo algorithm to solve the electronic structure of two-dimensional semiconductor quantum dots in external magnetic field. We present accurate many-body wave functions for the system in various magnetic field…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Ari Harju

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 propose a general framework for finding the ground state of many-body fermionic systems by using feed-forward neural networks. The anticommutation relation for fermions is usually implemented to a variational wave function by the Slater…

Strongly Correlated Electrons · Physics 2021-12-21 Koji Inui , Yasuyuki Kato , Yukitoshi Motome

The application of the diffusion Monte Carlo method to a strongly interacting Fermi system as normal liquid $^3$He is explored. We show that the fixed-node method together with the released-node technique and a systematic method to…

Statistical Mechanics · Physics 2009-10-31 Joaquim Casulleras , Jordi Boronat

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

Monte Carlo methods play important part in modern statistical physics. The application of these methods suffer from two main difficulties.The first is caused by the relatively small number of particles that can participate in any numerical…

Statistical Mechanics · Physics 2007-05-23 A. Brandt , V. Ilyin

We formulate a path-integral Monte Carlo algorithm for simulating lattice systems consisting of fictitious particles governed by a generalized exchange statistics. This method, initially proposed for continuum systems, introduces a…

Strongly Correlated Electrons · Physics 2025-08-19 Zhijie Fan , Tianning Xiao , Youjin Deng

A quantum implementation of the Stochastic Series Expansion (SSE) Monte Carlo method is proposed, and it is shown that quantum SSE offers significant advantages over classical implementations of SSE. In particular, for problems where…

Quantum Physics · Physics 2020-10-05 Kok Chuan Tan , Dhiman Bowmick , Pinaki Sengupta

Ab initio calculations play an essential role in our fundamental understanding of quantum many-body systems across many subfields, from strongly correlated fermions to quantum chemistry and from atomic and molecular systems to nuclear…