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A diffusion Monte Carlo algorithm is introduced that can determine the correct nodal structure of the wave function of a few-fermion system and its ground-state energy without an uncontrolled bias. This is achieved by confining signed…

Computational Physics · Physics 2020-02-05 Alexander A. Kunitsa , So Hirata

We report results of both Diffusion Quantum Monte Carlo(DMC) method and Reptation Quantum Monte Carlo(RMC) method on the potential energy curve of the helium dimer. We show that it is possible to obtain a highly accurate description of the…

Chemical Physics · Physics 2015-05-18 Xuebin Wu , Xianru Hu , Chenlei Du , Yunchuan Dai , Shibin Chu , Leibo Hu , Jianbo Deng , Yuanping Feng

We present a unified theory of the variational Monte Carlo (VMC) and determinant quantum Monte Carlo (DQMC) methods using a novel density matrix formulation of VMC. We introduce an efficient algorithm for VMC to compute correlation…

Strongly Correlated Electrons · Physics 2018-10-02 Mohammad-Sadegh Vaezi , Abolhassan Vaezi

We review the essentials of the formalism of quantum mechanics based on a deformed Heisenbeg algebra, leading to the existence of a minimal length scale. We compute in this context, the energy spectra of the pseudoharmonic oscillator and…

Quantum Physics · Physics 2017-11-15 Djamil Bouaziz

Compact and accurate wave functions can be constructed by quantum Monte Carlo methods. Typically, these wave functions consist of a sum of a small number of Slater determinants multiplied by a Jastrow factor. In this paper we study the…

Condensed Matter · Physics 2009-10-30 Chien-Jung Huang , C. J. Umrigar , M. P. Nightingale

Variational algorithms for strongly correlated chemical and materials systems are one of the most promising applications of near-term quantum computers. We present an extension to the variational quantum eigensolver that approximates the…

Quantum Physics · Physics 2020-08-26 William J. Huggins , Joonho Lee , Unpil Baek , Bryan O'Gorman , K. Birgitta Whaley

We compare the harmonic and anharmonic properties of the vibrational modes in 3-dimensional jammed packings of frictionless spheres interacting via repulsive, finite range potentials. A crossover frequency is apparent in the density of…

Soft Condensed Matter · Physics 2010-06-25 Ning Xu , Vincenzo Vitelli , Andrea J. Liu , Sidney R. Nagel

We investigate the use of optimized correlation consistent gaussian basis sets for the study of insulating solids with auxiliary-field quantum Monte Carlo (AFQMC). The exponents of the basis set are optimized through the minimization of the…

Chemical Physics · Physics 2021-02-03 Miguel A. Morales , Fionn D. Malone

We introduce a framework for the calculation of ground and excited state energies of bosonic systems suitable for near-term quantum devices and apply it to molecular vibrational anharmonic Hamiltonians. Our method supports generic reference…

Quantum Physics · Physics 2020-06-24 Pauline J. Ollitrault , Alberto Baiardi , Markus Reiher , Ivano Tavernelli

An algorithm is proposed to optimize quantum Monte Carlo (QMC) wave functions based on New ton's method and analytical computation of the first and second derivatives of the variati onal energy. This direct application of the variational…

Chemical Physics · Physics 2016-09-08 Xi Lin , Hongkai Zhang , Andrew M. Rappe

Quantum systems can be dynamically controlled using time-periodic external fields, leading to the concept of Floquet engineering, with promising technological applications. Computing Floquet energy spectra is harder than only computing…

Quantum Physics · Physics 2023-07-26 Benedikt Fauseweh , Jian-Xin Zhu

In this note, variational Monte Carlo method based on neural quantum states for spin systems is reviewed. Using a neural network as the wave function allows for a more generalized expression of various types of interactions, including…

Strongly Correlated Electrons · Physics 2024-06-04 Yuntai Song

Fixed-node diffusion Monte Carlo (DMC) is a stochastic algorithm for finding the lowest energy many-fermion wave function with the same nodal surface as a chosen trial function. It has proved itself among the most accurate methods available…

Condensed Matter · Physics 2009-10-31 W. M. C. Foulkes , Randolph Q. Hood , R. J. Needs

The recently proposed full configuration interaction quantum Monte Carlo method allows access to essentially exact ground-state energies of systems of interacting fermions substantially larger than previously tractable without knowledge of…

Computational Physics · Physics 2012-12-17 J. S. Spencer , N. S. Blunt , W. M. C. Foulkes

Accurate experimental values for the vibrational ground tone or fundamental vibrational energy splitting of H$_2$, HD, and D$_2$ are presented. Absolute accuracies of $2\times10^{-4}$ cm$^{-1}$ are obtained from Doppler-free laser…

The Diffusion Monte Carlo method is devoted to the computation of electronic ground-state energies of molecules. In this paper, we focus on implementations of this method which consist in exploring the configuration space with a {\bf fixed}…

Numerical Analysis · Mathematics 2007-05-23 Tony Lelievre , Mohamed El Makrini , Benjamin Jourdain

In a two-part publication, we propose and analyze a formal foundation for practical calculations of vibrational mode lifetimes in solids. The approach is based on a recursion method analysis of the Liouvillian. In the first part, we derived…

Materials Science · Physics 2010-04-28 Doyl Dickel , Murray S. Daw

A numerical simulation of vibrational excitation of molecules was devised, and used to excite computational models of common molecules into a prescribed, pure, normal vibration mode in the ground electronic state, with varying, controlable…

Astrophysics · Physics 2009-11-11 Renaud Papoular

Homonuclear molecules have emerged as a crucial component in the pursuit of frequency standards, offering a promising avenue for the discovery of new physics phenomena that transcend the standard model. They also provide a unique approach…

Atomic Physics · Physics 2024-10-29 T. Zalialiutdinov , Y. Demidov , D. Solovyev

We introduce an efficient and numerically stable technique to make use of a BCS trial wave function in the computation of correlation functions of strongly correlated quantum fermion systems. The technique is applicable to any projection…

Strongly Correlated Electrons · Physics 2019-08-28 Ettore Vitali , Peter Rosenberg , Shiwei Zhang
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