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Related papers: An introduction to quantum cluster methods

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Recent work has proposed solving the k-means clustering problem on quantum computers via the Quantum Approximate Optimization Algorithm (QAOA) and coreset techniques. Although the current method demonstrates the possibility of quantum…

Quantum Physics · Physics 2024-06-25 Canaan Yung , Muhammad Usman

The Coupled Cluster (CC) method is used to compute the electronic correlation energy in atoms and molecules and often leads to highly accurate results. However, due to its single-reference nature, standard CC in its projected form fails to…

In recent years, a better understanding of the Monte Carlo method has provided us with many new techniques in different areas of statistical physics. Of particular interest are so called cluster methods, which exploit the considerable…

Statistical Mechanics · Physics 2007-05-23 Werner Krauth

We present a review of the Unitary Coupled Cluster (UCC) ansatz and related ans\"atze which are used to variationally solve the electronic structure problem on quantum computers. A brief history of coupled cluster (CC) methods is provided,…

We study cluster perturbation theory [Phys. Rev. Lett. \textbf{84}, 522 (2000)] when auxiliary field quantum Monte Carlo method is used for solving the cluster hamiltonian. As a case study, we calculate the spectral functions of the Hubbard…

Strongly Correlated Electrons · Physics 2007-05-23 Fei Lin , Erik S. Sorensen , Catherine Kallin , A. John Berlinsky

Two of the primary sources of error in the Cluster dynamical mean-field theory (CDMFT) technique arise from the use of finite size clusters and finite size baths, which makes the development of impurity solvers that can treat larger systems…

Strongly Correlated Electrons · Physics 2023-12-12 P. Rosenberg , D. Sénéchal , A. -M. S. Tremblay , M. Charlebois

Entanglement is a defining property of quantum systems. For a subsystem of a larger quantum system, one can formally define an operator known as the modular Hamiltonian, which is closely linked to the entanglement properties of that…

Quantum Physics · Physics 2025-08-26 Ian T. Lim , Isaac H. Kim

We present second-order molecular cluster perturbation theory (MCPT(2)), a linear scaling methodology to calculate arbitrarily large systems with explicit calculation of individual wavefunctions in a coupled-cluster framework. This new…

Mean-field theory (MFT) is one of the main available tools for analytical calculations entailed in investigations regarding many-body systems. Recently, there have been an urge of interest in ameliorating this kind of method, mainly with…

Statistical Mechanics · Physics 2016-06-14 F. M. Zimmer , M. Schmidt , Jonas Maziero

We describe a compilation strategy for Variational Quantum Eigensolver (VQE) algorithms which use the Unitary Coupled Cluster (UCC) ansatz, designed to reduce circuit depth and gate count. This is achieved by partitioning Pauli exponential…

Quantum Physics · Physics 2020-08-28 Alexander Cowtan , Will Simmons , Ross Duncan

We review clustering as an analysis tool and the underlying concepts from an introductory perspective. What is clustering and how can clusterings be realised programmatically? How can data be represented and prepared for a clustering task?…

Machine Learning · Computer Science 2022-12-05 Jan-Oliver Felix Kapp-Joswig , Bettina G. Keller

We present the algorithmic details of the dynamical cluster approximation (DCA), with a quantum Monte Carlo (QMC) method used to solve the effective cluster problem. The DCA is a fully-causal approach which systematically restores non-local…

Strongly Correlated Electrons · Physics 2009-11-07 M. Jarrell , Th. Maier , C. Huscroft , S. Moukouri

We study electronic structures of two-dimensional quantum dots in strong magnetic fields using mean-field density-functional theory and exact diagonalization. Our numerically accurate mean-field solutions show a reconstruction of the…

Mesoscale and Nanoscale Physics · Physics 2009-09-29 H. Saarikoski , A. Harju , M. J. Puska , R. M. Nieminen

The variational cluster approach (VCA) is applied to the one-dimensional Hubbard model at zero temperature using clusters (chains) of up to ten sites with full diagonalization and the Lanczos method as cluster solver. Within the framework…

Strongly Correlated Electrons · Physics 2008-01-30 Matthias Balzer , Werner Hanke , Michael Potthoff

Quantum embedding methods have recently developed significantly to model large molecular structures. This work proposes a novel wave function theory in density functional theory (WTF-in-DFT) embedding scheme based on pair-coupled cluster…

Chemical Physics · Physics 2024-01-10 Rahul Chakraborty , Katharina Boguslawski , Paweł Tecmer

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

We propose a clustering-based approach for identifying coherent flow structures in continuous dynamical systems. We first treat a particle trajectory over a finite time interval as a high-dimensional data point and then cluster these data…

Dynamical Systems · Mathematics 2022-12-27 Wai Ming Chau , Shingyu Leung

We have designed a new multi-scale approach for Strongly Correlated Systems by combining the Dynamical Cluster Approximation (DCA) and the recently introduced dual-fermion formalism. This approach employs an exact mapping from a real…

Strongly Correlated Electrons · Physics 2011-10-12 S. -X. Yang , H. Fotso , H. Hafermann , K. -M. Tam , J. Moreno , T. Pruschke , M. Jarrell

We formulate a quantum embedding algorithm in real-space for the simultaneous theoretical treatment of nonlocal electronic correlations and disorder, the coherent cellular dynamical mean-field theory (C-CDMFT). This algorithm combines the…

Strongly Correlated Electrons · Physics 2026-01-09 Patrick Tscheppe , Marcel Klett , Henri Menke , Sabine Andergassen , Niklas Enderlein , Philipp Hansmann , Thomas Schäfer

An electrodynamical coupled cluster (CC) methodology starting from a covariant formalism and an equal time approximation, and finally based on the Dirac-Fock picture of the electron and positron fields and Coulomb gauge, is given here. The…

Atomic Physics · Physics 2019-04-30 Sambhu N. Datta