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We introduce a novel method within the shell model Monte Carlo approach to calculate the ground-state energy of a finite-size system with an odd number of particles by using the asymptotic behavior of the imaginary-time single-particle…

Nuclear Theory · Physics 2015-06-03 Abhishek Mukherjee , Y. Alhassid

We perform a variational quantum Monte Carlo simulation of the transition from a Bardeen-Cooper-Schrieffer superfluid (BCS) to a Bose-Einstein condensate (BEC) at zero temperature. The model Hamiltonian involves an attractive short range…

Other Condensed Matter · Physics 2008-12-01 R. Jauregui , R. Paredes , L. Rosales-Zarate , G. Toledo Sanchez

Using the lattice Monte Carlo method, we compute the energy and Tan's contact in the ground state as well as the first excited state of few- to many-fermion systems in a one-dimensional periodic box. We focus on unpolarized systems of…

Quantum Gases · Physics 2015-08-05 L. Rammelmüller , W. J. Porter , A. C. Loheac , J. E. Drut

By performing a stochastic dynamic in a space of Slater determinants, the Full Configuration Interaction Quantum Monte Carlo (FCIQMC) method has been able to obtain energies which are essentially free from systematic error to the basis set…

Computational Physics · Physics 2014-10-10 George H. Booth , Deidre Cleland , Ali Alavi , David P. Tew

We introduce a novel many body method which combines two powerful many body techniques, viz., quantum Monte Carlo and coupled cluster theory. Coupled cluster wave functions are introduced as importance functions in a Monte Carlo method…

Nuclear Theory · Physics 2013-12-04 Alessandro Roggero , Abhishek Mukherjee , Francesco Pederiva

For some models of interacting fermions the known solution to the notorious sign-problem in Monte Carlo (MC) simulations is to work with macroscopic fermionic determinants; the price, however, is a macroscopic scaling of the numerical…

Strongly Correlated Electrons · Physics 2009-11-10 Evgueni Bourovski , Nikolay Prokof'ev , Boris Svistunov

We present a stable and systematically improvable quantum Monte Carlo (QMC) approach to calculating excited-state energies, which we implement using our fast randomized iteration method for the full configuration interaction problem…

Computational Physics · Physics 2023-10-03 Samuel M. Greene , Robert J. Webber , James E. T. Smith , Jonathan Weare , Timothy C. Berkelbach

A new Quantum Monte-Carlo (QMC) approach is proposed to investigate low-lying states of nuclei within the shell model. The formalism relies on a variational symmetry-restored wave-function to guide the underlying Brownian motion. Sign/phase…

Nuclear Theory · Physics 2015-10-20 Jérémy Bonnard , Olivier Juillet

We investigate the quantum breathing mode (monopole oscillation) of trapped fermionic particles with Coulomb and dipole interaction in one and two dimensions. This collective oscillation has been shown to reveal detailed information on the…

Quantum Physics · Physics 2014-03-03 Jan Willem Abraham , Michael Bonitz , Chris McDonald , Gianfranco Orlando , Thomas Brabec

An ultracold Fermi gas with a zero-range attractive potential in the unitary limit is investigated using variational and diffusion Monte Carlo methods. Previous calculations have used a finite range interactions and extrapolate the results…

Quantum Gases · Physics 2015-06-23 Renato Pessoa , S. A. Vitiello , K. E. Schmidt

We use Quantum Monte Carlo (QMC) simulations to study the pairing mechanism in a one-dimensional fermionic system governed by the Hubbard model with attractive contact interaction and with imbalance between the two spin populations. This is…

Quantum Gases · Physics 2015-03-17 M. J. Wolak , V. G. Rousseau , G. G. Batrouni

The entanglement entropy probing novel phases and phase transitions numerically via quantum Monte Carlo has made great achievements in large-scale interacting spin/boson systems. In contrast, the numerical exploration in interacting fermion…

Statistical Mechanics · Physics 2025-05-15 Weilun Jiang , Gaopei Pan , Zhe Wang , Bin-Bin Mao , Heng Shen , Zheng Yan

We demonstrate that the inclusion of a BCS importance function dramatically increases the efficiency of the auxiliary field method for strong pairing. We calculate the ground-state energy of an unpolarized fermi gas at unitarity with up to…

Quantum Gases · Physics 2011-12-12 J. Carlson , Stefano Gandolfi , Kevin E. Schmidt , Shiwei Zhang

The variational Monte Carlo method is used to find the ground state of six quarks confined to a cavity of diameter R_c, interacting via an assumed non-relativistic constituent quark model (CQM) Hamiltonian. We use a flux-tube model…

Nuclear Theory · Physics 2009-11-06 Mark W. Paris , Vijay R. Pandharipande

We employ \textit{ab initio} methods of quantum chemistry to investigate spin-1/2 fermions interacting via a two-body contact potential in a one-dimensional harmonic trap. The convergence of the total energy with the size of the…

The new {\em ab initio} quantum path integral Monte Carlo approach has been developed and applied for the entropy difference calculations for the strongly coupled degenerated uniform electron gas (UEG), a well--known model of simple metals.…

Plasma Physics · Physics 2021-07-28 Vladimir Filinov , Pavel Levashov , Alexander Larkin

The auxiliary-field quantum Monte Carlo (AFMC) method is a powerful and widely used technique for ground-state and finite-temperature simulations of quantum many-body systems. We introduce several algorithmic improvements for…

Computational Physics · Physics 2021-03-18 C. N. Gilbreth , S. Jensen , Y. Alhassid

Using quantum Monte Carlo (QMC) simulations we study the ground-state properties of the one-dimensional fermionic Hubbard model in traps with an underlying lattice. Since due to the confining potential the density is space dependent,…

Strongly Correlated Electrons · Physics 2007-05-23 Marcos Rigol , Alejandro Muramatsu

The Green's function Monte Carlo (GFMC) method provides accurate solutions to the nuclear many-body problem and predicts properties of light nuclei starting from realistic two- and three-body interactions. Controlling the GFMC fermion-sign…

Nuclear Theory · Physics 2023-04-07 Gurtej Kanwar , Alessandro Lovato , Noemi Rocco , Michael Wagman

Using two different numerical methods, we study the behavior of two-component Fermi gases interacting through short-range s-wave interactions in a harmonic trap. A correlated Gaussian basis-set expansion technique is used to determine the…

Other Condensed Matter · Physics 2009-11-13 J. von Stecher , Chris H. Greene , D. Blume