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We present a simple and stable numerical method to approximate the ground state of a quantum many-body system by multiple determinant states. This method searches these determinant states one by one according to the matching pursuit…

Strongly Correlated Electrons · Physics 2009-11-13 Quanlin Jie

We discuss the main aspects of the fixed-node quantum Monte Carlo method for lattice fermions and its recent application to the problem of phase separation in the 2D Hubbard model, along with virtues, limitations and perspectives of this…

Strongly Correlated Electrons · Physics 2007-05-23 Giovanni B. Bachelet , Andrea C. Cosentini

We discuss a projector Monte Carlo method for quantum spin models formulated in the valence bond basis, using the S=1/2 Heisenberg antiferromagnet as an example. Its singlet ground state can be projected out of an arbitrary basis state as…

Strongly Correlated Electrons · Physics 2007-05-23 A. W. Sandvik , K. S. D. Beach

In this work we present a novel quantum Monte-Carlo method for fermions, based on an exact decomposition of the Boltzmann operator $exp(-\beta H)$. It can be seen as a synthesis of several related methods. It has the advantage that it is…

Strongly Correlated Electrons · Physics 2009-10-31 S. Rombouts , K. Heyde , N. Jachowicz

Many electromagnetic properties of graphene can be described by the Hubbard model on a honeycomb lattice. However, this system suffers strongly from the sign problem if a chemical potential is included. Tensor network methods are not…

Computational Physics · Physics 2022-07-26 Manuel Schneider , Johann Ostmeyer , Karl Jansen , Thomas Luu , Carsten Urbach

We offer a new proposal for the Monte Carlo treatment of many-fermion systems in continuous space. It is based upon Diffusion Monte Carlo with significant modifications: correlated pairs of random walkers that carry opposite signs;…

Condensed Matter · Physics 2009-10-31 M. H. Kalos , Francesco Pederiva

The Fermi-Hubbard model is of fundamental importance in condensed-matter physics, yet is extremely challenging to solve numerically. Finding the ground state of the Hubbard model using variational methods has been predicted to be one of the…

Quantum Physics · Physics 2021-01-04 Chris Cade , Lana Mineh , Ashley Montanaro , Stasja Stanisic

Quantum Monte Carlo methods are used to calculate various ground state properties of charged bosons in two dimensions, throughout the whole density range where the fluid phase is stable. Wigner crystallization is predicted at $r_s\simeq…

Condensed Matter · Physics 2018-05-01 S. De Palo , S. Conti , S. Moroni

We study a classical fully-frustrated honeycomb lattice Ising model using Markov chain Monte Carlo methods and exact calculations . The Hamiltonian realizes a degenerate ground state manifold of equal-energy states, where each hexagonal…

Statistical Mechanics · Physics 2009-06-02 Shawn Andrews , Hans De Sterck , Stephen Inglis , Roger G. Melko

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

A new computational method for finite-temperature properties of strongly correlated electrons is proposed by extending the variational Monte Carlo method originally developed for the ground state. The method is based on the path integral in…

Strongly Correlated Electrons · Physics 2016-06-10 Kensaku Takai , Kota Ido , Takahiro Misawa , Youhei Yamaji , Masatoshi Imada

In this paper we explore new ways to study the zero temperature limit of quantum statistical mechanics using Quantum Monte Carlo simulations. We develop a Quantum Monte Carlo method in which one fixes the ground state energy as a parameter.…

Statistical Mechanics · Physics 2012-03-30 Edward Farhi , Jeffrey Goldstone , David Gosset , Harvey B. Meyer

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

The tensor network algorithm, a family of prevalent numerical methods for quantum many-body problems, aptly captures the entanglement properties intrinsic to quantum systems, enabling precise representation of quantum states. However, its…

Strongly Correlated Electrons · Physics 2024-06-26 He-Yu Lin , Yibin Guo , Rong-Qiang He , Z. Y. Xie , Zhong-Yi Lu

The ground state properties of a single-component one-dimensional Coulomb gas are investigated. We use Bose-Fermi mapping for the ground state wave function which permits to solve the Fermi sign problem in the following respects (i) the…

Quantum Gases · Physics 2014-03-31 G. E. Astrakharchik , M. D. Girardeau

Recent refinements of analytical and numerical methods have improved our understanding of the ground-state phase diagram of the two-dimensional (2D) Hubbard model. Here we focus on variational approaches, but comparisons with both Quantum…

Strongly Correlated Electrons · Physics 2009-07-25 D. Baeriswyl , D. Eichenberger , M. Menteshashvili

We study a trapped system of fermions with an attractive zero-range two-body interaction using the Shell-Model Monte Carlo method. The method provides {\em ab initio} results in the low $N$ limit where mean-field theory is not applicable.…

Superconductivity · Physics 2008-08-04 N. T. Zinner , K. Mølmer , C. Özen , K. Langanke , D. J. Dean

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the associated density of states via a Monte…

Statistical Mechanics · Physics 2012-05-16 Cedric Gommes , Yang Jiao , Salvatore Torquato

A simple, general and practically exact method, Entanglement Perturbation Theory (EPT), is formulated to calculate the ground states of 2D macroscopic quantum systems with translational symmetry. An emphasis will be placed on the…

Strongly Correlated Electrons · Physics 2015-05-19 S. G. Chung , K. Ueda

The wavefunction of an incommensurate ground state for a one-dimensional discrete sine-Gordon model -- the Frenkel-Kontorova (FK) model -- at zero temperature is calculated by the quantum Monte Carlo method. It is found that the ground…

Condensed Matter · Physics 2009-10-31 Bambi Hu , Baowen Li