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Neutron matter, through its connection to neutron stars as well as systems like cold atom gases, is one of the most interesting yet computationally accessible systems in nuclear physics. The Configuration-Interaction Monte Carlo (CIMC)…

Nuclear Theory · Physics 2023-04-19 Pierre Arthuis , Carlo Barbieri , Francesco Pederiva , Alessandro Roggero

In this article we study examples of systematic biases that can occur in quantum Monte Carlo methods due to the accumulation of non-linear expectation values, and approaches by which these errors can be corrected. We begin with a study of…

Strongly Correlated Electrons · Physics 2018-08-15 Nick S. Blunt , Ali Alavi , George H. Booth

The possibility to simulate the properties of many-body open quantum systems with a large number of degrees of freedom is the premise to the solution of several outstanding problems in quantum science and quantum information. The challenge…

Quantum Physics · Physics 2019-07-03 Alexandra Nagy , Vincenzo Savona

The VB-QMC method is presented in this chapter. It consists of using in quantum Monte Carlo (QMC) approaches with a wave function expressed as a usually short expansion of classical Valence-Bond (VB) structures supplemented by a Jastrow…

Chemical Physics · Physics 2022-08-01 Slavko Radenković , Dominik Domin , Julien Toulouse , Benoît Braïda

The quark-meson coupling (QMC) model for nuclear matter, which describes nuclear matter as non-overlapping MIT bags bound by the self-consistent exchange of scalar and vector mesons is modified by the introduction of a density dependent bag…

Nuclear Theory · Physics 2009-10-28 Xuemin Jin , B. K. Jennings

Mean-field molecular dynamics based on path integrals is used to approximate canonical quantum observables for particle systems consisting of nuclei and electrons. A computational bottleneck is the sampling from the Gibbs density of the…

Numerical Analysis · Mathematics 2023-11-30 Xin Huang , Petr Plechac , Mattias Sandberg , Anders Szepessy

Fixed-node diffusion Monte Carlo (FNDMC) is a stochastic quantum many-body method that has a great potential in electronic structure theory. We examine how FNDMC satisfies exact constraints, linearity and derivative discontinuity of total…

Chemical Physics · Physics 2019-10-16 Matej Ditte , Matus Dubecky

We introduce a particle-number reprojection method in the shell model Monte Carlo that enables the calculation of observables for a series of nuclei using a Monte Carlo sampling for a single nucleus. The method is used to calculate nuclear…

Nuclear Theory · Physics 2009-10-31 Y. Alhassid , S. Liu , H. Nakada

This paper proposes an efficient method for the simultaneous estimation of the state of a quantum system and the classical parameters that govern its evolution. This hybrid approach benefits from efficient numerical methods for the…

Quantum Physics · Physics 2017-11-08 Jason F Ralph , Simon Maskell , Kurt Jacobs

A method for making realistic estimates of the density of levels in even-even nuclei is presented making use of the Monte Carlo shell model (MCSM). The procedure follows three basic steps: (1) computation of the thermal energy with the…

Nuclear Theory · Physics 2009-10-30 W. E. Ormand

In quantum information theory, there is an explicit mapping between general unitary dynamics and Hermitian ground state eigenvalue problems known as the Feynman-Kitaev Clock. A prominent family of methods for the study of quantum ground…

Quantum Physics · Physics 2015-01-14 Jarrod R. McClean , Alán Aspuru-Guzik

We present clear numerical evidence for the coexistence of metallic and insulating dynamical mean field theory(DMFT) solutions in a half-filled single-band Hubbard model with bare semicircular density of states at finite temperatures.…

Strongly Correlated Electrons · Physics 2009-10-31 Jaewook Joo , Viktor Oudovenko

The recently developed auxiliary field diffusion Monte Carlo method is applied to compute the equation of state and the compressibility of neutron matter. By combining diffusion Monte Carlo for the spatial degrees of freedom and auxiliary…

Nuclear Theory · Physics 2009-11-10 A. Sarsa , S. Fantoni , K. E. Schmidt , F. Pederiva

Many approaches to three-dimensional constrained macromolecular chains at thermal equilibrium, at about room temperatures, are based upon constrained Classical Hamiltonian Dynamics (cCHDa). Quantum-mechanical approaches (QMa) have also been…

Soft Condensed Matter · Physics 2011-11-08 Gabriel F. Calvo , Ramon F. Alvarez-Estrada

We applied a mean-field approach associated to Monte Carlo simulations in order to study the spin-1 ferromagnetic Blume-Capel model in the square and the linear lattice. This new technique, which we call MFT-MC, determines the molecular…

Statistical Mechanics · Physics 2016-07-06 J. Roberto Viana , Octavio D. Rodriguez Salmon , Minos A. Neto

The kinetics of the chiral phase transition is studied within a linear quark-meson-$\sigma$ model, using a Monte-Carlo approach to semiclassical particle-field dynamics. The meson fields are described on the mean-field level and quarks and…

High Energy Physics - Phenomenology · Physics 2015-09-30 Carsten Greiner , Christian Wesp , Hendrik van Hees , Alex Meistrenko

We propose a new variational Monte Carlo (VMC) approach based on the Krylov subspace for large-scale shell-model calculations. A random walker in the VMC is formulated with the $M$-scheme representation, and samples a small number of…

Nuclear Theory · Physics 2015-06-15 Noritaka Shimizu , Takahiro Mizusaki , Kazunari Kaneko

Efficient continuous time quantum Monte Carlo (CT-QMC) algorithms that do not suffer from time discretization errors have become the state-of-the-art for most discrete quantum models. They have not been widely used yet for fermionic quantum…

Strongly Correlated Electrons · Physics 2015-07-08 Mauro Iazzi , Matthias Troyer

The rotational bands in nuclei with $Z \approx 100$ are investigated systematically by using a cranked shell model (CSM) with the pairing correlations treated by a particle-number conserving (PNC) method, in which the blocking effects are…

Nuclear Theory · Physics 2012-01-27 Zhen-Hua Zhang , Xiao-Tao He , Jin-Yan Zeng , En-Guang Zhao , Shan-Gui Zhou

Quantum Monte Carlo simulations offer an unbiased means to study the static and dynamic properties of quantum critical systems, while quantum field theory provides direct analytical results. We study three dimensional, critical quantum…

Strongly Correlated Electrons · Physics 2017-11-15 H. D. Scammell , Y. Kharkov , Yan Qi Qin , Zi Yang Meng , B. Normand , O. P. Sushkov