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Gaussian Quantum Monte Carlo (GQMC) is a stochastic phase space method for fermions with positive weights. In the example of the Hubbard model close to half filling it fails to reproduce all the symmetries of the ground state leading to…

Strongly Correlated Electrons · Physics 2008-03-04 P. Corboz , A. Kleine , F. F. Assaad , I. P. McCulloch , U. Schollwöck , M. Troyer

We present an accurate numerical study of the equation of state of nuclear matter based on realistic nucleon--nucleon interactions by means of Auxiliary Field Diffusion Monte Carlo (AFDMC) calculations. The AFDMC method samples the spin and…

Nuclear Theory · Physics 2008-11-26 Stefano Gandolfi , Francesco Pederiva , Stefano Fantoni , Kevin E. Schmidt

While Diffusion Monte Carlo (DMC) is in principle an exact stochastic method for \textit{ab initio} electronic structure calculations, in practice the fermionic sign problem necessitates the use of the fixed-node approximation and trial…

Fermionic phase space representations are a promising method for studying correlated fermion systems. The fermionic Q-function and P-function have been defined using Gaussian operators of fermion annihilation and creation operators. The…

Quantum Physics · Physics 2018-05-31 Ria Rushin Joseph , Laura E. C. Rosales-Zárate , Peter D. Drummond

Preparing matrix product states (MPSs) on quantum computers is an essential routine in the simulation of many-body physics. However, widely-used schemes based on staircase circuits are often too deep to execute on current hardware. Here we…

Recent work by Wu {\em et al.} [arXiv:1910.11011] proposed a numerical method, so-called matrix product operator-matrix product state (MPO-MPS) method, by which several types of quantum many-body wave functions, in particular, the projected…

Strongly Correlated Electrons · Physics 2020-04-29 Hui-Ke Jin , Hong-Hao Tu , Yi Zhou

We expand upon the recent semi-stochastic adaptation to full configuration interaction quantum Monte Carlo (FCIQMC). We present an alternate method for generating the deterministic space without a priori knowledge of the wave function and…

Computational Physics · Physics 2015-11-17 N. S. Blunt , Simon D. Smart , J. A. F. Kersten , J. S. Spencer , George H. Booth , Ali Alavi

We develop a new projected wave function approach which is based on projection operators in the form of matrix-product operators (MPOs). Our approach allows to variationally improve the short range entanglement of a given trial wave…

Computational Physics · Physics 2015-06-04 Chung-Pin Chou , Frank Pollmann , Ting-Kuo Lee

Quantum machine learning (QML) is a rapidly expanding field that merges the principles of quantum computing with the techniques of machine learning. One of the powerful mathematical frameworks in this domain is tensor networks. These…

Quantum Physics · Physics 2025-05-27 Alex Mossi , Bojan Žunkovic , Kyriakos Flouris

As in the density matrix renormalization group (DMRG) method, approximating many-body wave function of electrons using a matrix product state (MPS) is a promising way to solve electronic structure problems. The expressibility of an MPS is…

Quantum Physics · Physics 2023-01-18 Yi Fan , Jie Liu , Zhenyu Li , Jinlong Yang

Quantum Monte Carlo (QMC) methods represent a powerful family of computational techniques for tackling complex quantum many-body problems and performing calculations of stationary state properties. QMC is among the most accurate and…

Materials Science · Physics 2025-01-08 Alfonso Annarelli , Dario Alfè , Andrea Zen

Ultra-short pulses propagating in nonlinear nanophotonic waveguides can simultaneously leverage both temporal and spatial field confinement, promising a route towards single-photon nonlinearities in an all-photonic platform. In this…

Quantum Physics · Physics 2021-10-05 Ryotatsu Yanagimoto , Edwin Ng , Logan G. Wright , Tatsuhiro Onodera , Hideo Mabuchi

Correlated electron states are at the root of many important phenomena including unconventional superconductivity (USC), where electron-pairing arises from repulsive interactions. Computing the properties of correlated electrons, such as…

The projective quantum Monte Carlo (PQMC) algorithms are among the most powerful computational techniques to simulate the ground state properties of quantum many-body systems. However, they are efficient only if a sufficiently accurate…

Computational Physics · Physics 2019-10-04 S. Pilati , E. M. Inack , P. Pieri

We introduce methodologies for highly scalable quantum Monte Carlo simulations of electron-phonon models, and report benchmark results for the Holstein model on the square lattice. The determinant quantum Monte Carlo (DQMC) method is a…

Strongly Correlated Electrons · Physics 2022-07-18 Benjamin Cohen-Stead , Owen Bradley , Cole Miles , George Batrouni , Richard Scalettar , Kipton Barros

The generalization of matrix product states (MPS) to continuous systems, as proposed in the breakthrough paper [F. Verstraete, J.I. Cirac, Phys. Rev. Lett. 104, 190405(2010)], provides a powerful variational ansatz for the ground state of…

Strongly Correlated Electrons · Physics 2017-06-07 Martin Ganahl , Julian Rincon , Guifre Vidal

We have used the auxiliary-field quantum Monte Carlo (AFQMC) many-body approach on the lattice to study the equation of state for a fermionic impurity interacting with a background sea of spin-polarized fermions. The impurity, or polaron,…

Nuclear Theory · Physics 2026-04-13 Ryan Curry , Jasmine Kozar , Alexandros Gezerlis

We present an implementation of Quantum Annealing (QA) via lattice Green's function Monte Carlo (GFMC), focusing on its application to the Ising spin-glass in transverse field. In particular, we study whether or not such method is more…

Disordered Systems and Neural Networks · Physics 2015-06-25 Lorenzo Stella , Giuseppe E. Santoro

We show that the formalism of tensor-network states, such as the matrix product states (MPS), can be used as a basis for variational quantum Monte Carlo simulations. Using a stochastic optimization method, we demonstrate the potential of…

Strongly Correlated Electrons · Physics 2009-11-13 A. W. Sandvik , G. Vidal

We report the development of a python-based auxiliary-field quantum Monte Carlo (AFQMC) program, ipie, with preliminary timing benchmarks and new AFQMC results on the isomerization of [Cu$_2$O$_2$$]^{2+}$. We demonstrate how implementations…

Chemical Physics · Physics 2022-11-09 Fionn D. Malone , Ankit Mahajan , James S. Spencer , Joonho Lee