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The auxiliary-field quantum Monte Carlo (AFQMC) method is a general numerical method for correlated many-electron systems, which is being increasingly applied in lattice models, atoms, molecules, and solids. Here we introduce the theory and…

Computational Physics · Physics 2021-02-24 Hao Shi , Shiwei Zhang

We revisit the infinite variance problem in fermionic Monte Carlo simulations, which is widely encountered in areas ranging from condensed matter to nuclear and high-energy physics. The different algorithms, which we broadly refer to as…

Strongly Correlated Electrons · Physics 2025-12-12 Zhou-Quan Wan , Shiwei Zhang

The reduced density matrix of excitons coupled to a phonon bath at a finite temperature is studied using the path integral Monte Carlo method. Appropriate choices of estimators and importance sampling schemes are crucial to the performance…

Quantum Physics · Physics 2015-06-04 Sangwoo Shim , Alán Aspuru-Guzik

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 possible solution of the notorious sign problem preventing direct Monte Carlo calculations for systems with non-zero chemical potential is to deform the integration region in the complex plane to a Lefschetz thimble. We investigate this…

High Energy Physics - Lattice · Physics 2016-01-27 Andrei Alexandru , Gokce Basar , Paulo Bedaque

We present a quantum Monte Carlo (QMC) technique for calculating the exact finite-temperature properties of Bose-Fermi mixtures. The Bose-Fermi Auxiliary-Field Quantum Monte Carlo (BF-AFQMC) algorithm combines two methods, a…

Quantum Gases · Physics 2012-12-04 Brenda M. Rubenstein , Shiwei Zhang , David R. Reichman

A recent reformulation [1] of the problem of Coulomb gases in the presence of a dynamical dielectric medium showed that finite temperature simulations of such systems can be accomplished on the basis of completely local Hamiltonians on a…

Soft Condensed Matter · Physics 2009-11-11 A. Duncan , R. D. Sedgewick

Monte Carlo integration approximates an integral of a black-box function by taking the average of many evaluations (i.e., samples) of the function (integrand). For $N$ queries of the integrand, Monte Carlo integration achieves the…

Quantum Physics · Physics 2020-04-27 N. H. Shimada , Toshiya Hachisuka

We propose a quantum Monte Carlo algorithm capable of simulating the Bose-Hubbard model on arbitrary graphs, obviating the need for devising lattice-specific updates for different input graphs. We show that with our method, which is based…

Statistical Mechanics · Physics 2024-04-29 Itay Hen , Emre Akaturk

Simulating long-range interacting systems is a challenging task due to its computational complexity that the computational effort for each local update is of order $\cal{O}$$(N)$, where $N$ is the size of system. Recently, a technique,…

Computational Physics · Physics 2025-11-14 Zhijie Fan , Chao Zhang , Youjin Deng

We present an exact local bosonic algorithm for the simulation of dynamical fermions in lattice QCD. It is based on a non-hermitian polynomial approximation of the inverse of the quark matrix and a global Metropolis accept/reject correction…

High Energy Physics - Lattice · Physics 2007-05-23 Ph. de Forcrand , A. Galli

We introduce a new numerical technique -- bosonic auxiliary-field Monte Carlo (bAFMC) -- which allows to calculate the thermal properties of large lattice-boson systems within a systematically improvable semiclassical approach, and which is…

Strongly Correlated Electrons · Physics 2017-08-02 Daniele Malpetti , Tommaso Roscilde

We study the real-time simulation of open quantum systems, where the system is modeled by a spin chain, with each spin associated with its own harmonic bath. Our method couples the inchworm method for the spin-boson model and the modular…

Quantum Physics · Physics 2023-12-05 Geshuo Wang , Zhenning Cai

Quantum Monte Carlo (QMC) methods are essential for the numerical study of large-scale quantum many-body systems, yet their utility has been significantly hampered by the difficulty in computing key quantities such as off-diagonal operators…

Quantum Physics · Physics 2025-11-19 Poetri Sonya Tarabunga , Yi-Ming Ding

We provide a pedagogical introduction to the two main variants of real-space quantum Monte Carlo methods for electronic-structure calculations: variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC). Assuming no prior knowledge on…

Chemical Physics · Physics 2015-08-13 Julien Toulouse , Roland Assaraf , C. J. Umrigar

A hypothetical exclusion principle for quantum particles is introduced that generalizes the exclusion and inclusion principles for fermions and bosons, respectively: the correlated exclusion principle. The sum-free condition for Schur…

Quantum Physics · Physics 2020-10-02 Miguel A. Martin-Delgado

The recently developed density matrix quantum Monte Carlo (DMQMC) algorithm stochastically samples the N -body thermal density matrix and hence provides access to exact properties of many-particle quantum systems at arbitrary temperatures.…

Strongly Correlated Electrons · Physics 2015-10-15 Fionn D. Malone , N. S. Blunt , James J. Shepherd , D. K. K. Lee , J. S. Spencer , W. M. C. Foulkes

We present a novel and open-source implementation of the worm algorithm, which is an algorithm to simulate Bose-Hubbard and sign-positive spin models using a path integral representation of the partition function. The code can deal with…

Statistical Mechanics · Physics 2022-10-03 Nicolas Sadoune , Lode Pollet

Quantum Monte Carlo (QMC) methods such as Variational Monte Carlo, Diffusion Monte Carlo or Path Integral Monte Carlo are the most accurate and general methods for computing total electronic energies. We will review methods we have…

Computational Physics · Physics 2007-05-23 David Ceperley , Mark Dewing , Carlo Pierleoni

We develop the self-learning Monte Carlo (SLMC) method, a general-purpose numerical method recently introduced to simulate many-body systems, for studying interacting fermion systems. Our method uses a highly-efficient update algorithm,…

Strongly Correlated Electrons · Physics 2017-06-14 Junwei Liu , Huitao Shen , Yang Qi , Zi Yang Meng , Liang Fu