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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

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

We present a new Hamiltonian partitioning which converges an arbitrary number of states of interest in the effective Hamiltonian to the full configuration interaction limits simultaneously. This feature is quite useful for the recently…

Chemical Physics · Physics 2015-12-17 Seiichiro Ten-no

We introduce an algorithm for sampling many-body quantum states in Fock space. The algorithm efficiently samples states with probability approximately proportional to an arbitrary function of the second-quantized Hamiltonian matrix element…

Strongly Correlated Electrons · Physics 2016-04-28 Adam Holmes , Hitesh J. Changlani , C. J. Umrigar

We present a new method for the optimization of large configuration interaction (CI) expansions in the quantum Monte Carlo (QMC) framework. The central idea here is to replace the non-orthogonal variational optimization of CI coefficients…

Chemical Physics · Physics 2022-05-26 Abdallah Ammar , Emmanuel Giner , Anthony Scemama

Self-learning Monte Carlo method (SLMC), using a trained effective model to guide Monte Carlo sampling processes, is a powerful general-purpose numerical method recently introduced to speed up simulations in (quantum) many-body systems. In…

Strongly Correlated Electrons · Physics 2018-07-18 Chuang Chen , Xiao Yan Xu , Junwei Liu , George Batrouni , Richard Scalettar , Zi Yang Meng

We propose quantum-selected configuration interaction (QSCI), a class of hybrid quantum-classical algorithms for calculating the ground- and excited-state energies of many-electron Hamiltonians on noisy quantum devices. Suppose that an…

Quantum Physics · Physics 2023-02-23 Keita Kanno , Masaya Kohda , Ryosuke Imai , Sho Koh , Kosuke Mitarai , Wataru Mizukami , Yuya O. Nakagawa

In this work, we introduce a simple modification of the Monte Carlo algorithm, which we call step Monte Carlo (sMC). The sMC approach allows to simulate processes far from equilibrium and obtain information about the dynamic properties of…

Other Condensed Matter · Physics 2023-12-15 Dariusz Sztenkiel

Accurate solution of the many-electron problem including correlations remains intractable except for few-electron systems. Describing interacting electrons as a superposition of independent electron configurations results in an apparent…

Computational Physics · Physics 2024-02-20 J. C. Greer

We propose the use of preconditioning in FCIQMC which, in combination with perturbative estimators, greatly increases the efficiency of the algorithm. The use of preconditioning allows a time step close to unity to be used (without…

Chemical Physics · Physics 2019-05-17 Nick S. Blunt , Alex J. W. Thom , Charles J. C. Scott

Within Full Configuration Interaction Quantum Monte Carlo, we investigate how the statistical error behaves as a function of the parameters which control the stochastic sampling. We define the inefficiency as a measure of the statistical…

Chemical Physics · Physics 2016-03-15 W. A. Vigor , J. S. Spencer , M. J. Bearpark , A. J. W. Thom

We present a new high-performance configuration interaction code optimally designed for the calculation of the lowest energy eigenstates of a few electrons in semiconductor quantum dots (also called artificial atoms) in the strong…

Strongly Correlated Electrons · Physics 2007-05-23 Massimo Rontani , Carlo Cavazzoni , Devis Bellucci , Guido Goldoni

One of the open challenges in quantum computing is to find meaningful and practical methods to leverage quantum computation to accelerate classical machine learning workflows. A ubiquitous problem in machine learning workflows is sampling…

Quantum Physics · Physics 2024-08-08 Owen Lockwood , Peter Weiss , Filip Aronshtein , Guillaume Verdon

In low-temperature high-density plasmas quantum effects of the electrons are becoming increasingly important. This requires the development of new theoretical and computational tools. Quantum Monte Carlo methods are among the most…

Statistical Mechanics · Physics 2014-08-12 T. Schoof , S. Groth , M. Bonitz

The convergence of full configuration interaction quantum Monte Carlo (FCIQMC) is accelerated using a quasi-Newton propagation (QN) which can also be applied to coupled cluster Monte Carlo (CCMC). The computational scaling of this optimised…

Chemical Physics · Physics 2020-06-11 Verena A. Neufeld , Alex J. W. Thom

Random samples of quantum states with specific properties are useful for various applications, such as Monte Carlo integration over the state space. In the high-dimensional situations that one encounters already for a few qubits, the…

Quantum Physics · Physics 2026-02-02 Weijun Li , Rui Han , Jiangwei Shang , Hui Khoon Ng , Berthold-Georg Englert

Particle Markov Chain Monte Carlo (PMCMC) is a general computational approach to Bayesian inference for general state space models. Our article scales up PMCMC in terms of the number of observations and parameters by generating the…

Methodology · Statistics 2023-07-04 David Gunawan , Chris Carter , Robert Kohn

Quantum computing offers an alternative paradigm for addressing combinatorial optimization problems compared to classical computing. Despite recent hardware improvements, the execution of empirical quantum optimization experiments at scales…

We introduce the energy-stepping Monte Carlo (ESMC) method, a Markov chain Monte Carlo (MCMC) algorithm based on the conventional dynamical interpretation of the proposal stage but employing an energy-stepping integrator. The…

Mathematical Physics · Physics 2023-12-13 Ignacio Romero , Michael Ortiz

We present \emph{multi-qubit correction} (MQC) as a novel postprocessing method for quantum annealers that views the evolution in an open-system as a Gibbs sampler and reduces a set of excited states to a new synthetic state with lower…

Quantum Physics · Physics 2021-07-13 Ramin Ayanzadeh , John Dorband , Milton Halem , Tim Finin