We present a new approach for Monte Carlo simulations of lattice quantum spin systems which is able to eliminate the negative sign problem. Its complexity is linear in the volume of the lattice. Its efficiency is tested on a simple 2-dimensional fermionic model. The investigation of quantum spin systems is important for understanding the physics related to strongly correlated electrons and high...

Quasi-Monte Carlo (QMC) methods have become important numerical tools in computational finance. Many studies have demonstrated the greater efficiency of QMC relative to Monte Carlo (MC) methods, even for pricing high-dimensional exotic derivative securities. Some of these studies have argued the importance of effective dimension in determining the efficiency of QMC. Consequently, dimension redu...

Developing accurate and computationally efficient methods to calculate the electronic structure and total energy of correlated-electron materials has been a very challenging task in condensed matter physics and materials science. Recently, we have developed a correlation matrix renormalization (CMR) method which does not assume any empirical Coulomb interaction U parameters and does not have do...

We investigate the properties of a dilute gas impurities embedded in an ultracold bosons that forms Bose–Einstein condensate (BEC). This work focuses mainly on equation state (EoS) impurity at zero temperature and induced interaction between mediated by host bath. use perturbative field-theory approaches, such as Hugenholtz–Pines formalism, weakly interacting regime. In turn, for strong interac...

We study equal weight numerical integration, or Quasi Monte Carlo (QMC) rules, for functions in a Sobolev space Hs(Sd) with smoothness parameter s > d/2 defined over the unit sphere Sd in Rd+1. Focusing on N-point configurations that achieve optimal order QMC error bounds (as is the case for efficient spherical designs), we are led to introduce the concept of QMC designs: these are sequences of...

Submitted for the MAR11 Meeting of The American Physical Society Quantum phase transitions in generalized J-Q models ARNAB SEN, ANDERS SANDVIK, Boston University — The “J-Q” model is an extension of the Heisenberg model which contains multi-spin interactions that suppress Néel order and lead to a valence-bond-solid (VBS) ground state. It is free from quantum Monte Carlo (QMC) sign problems. The...

We present a comparative study of the spatial distribution of the spin density of the ground state of CuCl2 using Density Functional Theory (DFT), quantum Monte Carlo (QMC), and post-Hartree-Fock wave function theory (WFT). A number of studies have shown that an accurate description of the electronic structure of the lowest-lying states of this molecule is particularly challenging due to the in...

A numerical method is presented for reproducing fermionic quantum gas microscope experiments in equilibrium. By employing nested componentwise direct sampling of fermion pseudo-density matrices, as they arise naturally determinantal Monte Carlo (QMC) simulations, a stream pseudo-snapshots occupation numbers on large systems can be produced. There sign problem even when the conventional QMC algo...

In these lectures, I will briefly review some of the Quantum Monte Carlo (QMC) methods that have been used to calculate properties of the “electron gas” and review properties that have been computed with these methods. (Note that this article is a mosaic of previously published works on this subject with very little genuinely new results. It is hoped that this collection will prove useful.) For...

We consider the problem of estimating expectations by using Markov chain Monte Carlo methods and improving accuracy replacing IID uniform random points with quasi-Monte (QMC) points. Recently, it has been shown that QMC remains consistent when driving sequences are completely uniformly distributed (CUD). However, definition CUD is not constructive, so an implementation method short-period Tausw...