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Related papers: Non-equilibrium cluster-perturbation theory

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Using the general argument in Borel resummation of perturbation theory that links the divergent perturbation theory to the nonperturbative effect we argue that the nonperturbative effect associated with the perturbation theory should have a…

High Energy Physics - Phenomenology · Physics 2009-11-07 Taekoon Lee

An algorithm, based on numerical description of the terms of many-body perturbation theory (Goldstone diagrams), is presented. The algorithm allows the use of the same piece of computer code to evaluate any particular diagram in any…

Atomic Physics · Physics 2015-05-13 V. A. Dzuba

Clustering with capacity constraints is a fundamental problem that attracted significant attention throughout the years. In this paper, we give the first FPT constant-factor approximation algorithm for the problem of clustering points in a…

Data Structures and Algorithms · Computer Science 2024-02-21 Sayan Bandyapadhyay , William Lochet , Saket Saurabh

The iterative qubit coupled cluster (iQCC) method is a systematic variational approach to solve the electronic structure problem on universal quantum computers. It is able to use arbitrarily shallow quantum circuits at expense of iterative…

Quantum Physics · Physics 2020-09-30 Ilya G. Ryabinkin , Artur F. Izmaylov , Scott N. Genin

We propose an improved scheme of perturbation theory based on our exact solution [An Min Wang, quant-ph/0611216] in general quantum systems independent of time. Our elementary start-point is to introduce the perturbing parameter as late as…

Quantum Physics · Physics 2007-05-23 An Min Wang

General and explicit predictions from the integrated perturbation theory (iPT) for power spectra and correlation functions of biased tracers are derived and presented in the one-loop approximation. The iPT is a general framework of the…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-05 Takahiko Matsubara

Coupled-cluster (CC) theory and Green's function many-body perturbation theory (MBPT) have long evolved as distinct yet complementary frameworks for describing electronic correlation. While CC methods employ exponential wavefunction…

Accurate electronic structure calculations might be one of the most anticipated applications of quantum computing.The recent landscape of quantum simulations within the Hartree-Fock approximation raises the prospect of substantial theory…

Quantum Physics · Physics 2023-08-04 Junxu Li , Xingyu Gao , Manas Sajjan , Ji-Hu Su , Zhao-Kai Li , Sabre Kais

This paper demonstrates that a computer aided perturbation theory can easily be realized by use of a cumulant approach. In contrast to a recent alternative formulation on the basis of Wegner's flow equation method the present approach can…

Strongly Correlated Electrons · Physics 2009-11-10 S. Sykora , A. Huebsch , K. W. Becker

A theory of clustering of inertial particles advected by a turbulent velocity field caused by an instability of their spatial distribution is suggested. The reason for the clustering instability is a combined effect of the particles inertia…

Chaotic Dynamics · Physics 2007-05-23 Tov Elperin , Nathan Kleeorin , Victor S. L'vov , Igor Rogachevskii , Dmitry Sokoloff

Methods which aim at universal applicability must be able to describe both weak and strong electronic correlation with equal facility. Such methods are in short supply. The combination of symmetry projection for strong correlation and…

Chemical Physics · Physics 2020-05-14 Yiheng Qiu , Thomas M. Henderson , Jinmo Zhao , Gustavo E. Scuseria

Recent disagreement between state-of-the-art quantum chemical methods, coupled cluster with single, double and perturbative triples excitations and fixed-node diffusion Monte Carlo, calls for systematic examination of possible sources of…

Chemical Physics · Physics 2025-05-14 S. Lambie , C. Rickert , D. Usvyat , A. Alavi , D. Kats

The recently introduced coupled cluster (CC) downfolding techniques for reducing the dimensionality of quantum many-body problems recast the CC formalism in the form of the renormalization procedure allowing, for the construction of…

Quantum Physics · Physics 2021-11-08 Nicholas P. Bauman , Karol Kowalski

In cluster-randomized trials (CRTs), entire clusters of individuals are randomized to treatment, and outcomes within a cluster are typically correlated. While frequentist approaches are standard practice for CRT analysis, Bayesian methods…

Methodology · Statistics 2025-11-27 Ruyi Liu , Joshua L. Warren , Yuki Ohnishi , Donna Spiegelman , Liangyuan Hu , Fan Li

We present a novel approach to spin-adapted coupled cluster theory. This approach is based on the entanglement of an open-shell molecule with electrons in a non-interacting bath; together they form a closed-shell state. For the total…

Chemical Physics · Physics 2023-05-22 Sarai Dery Folkestad , Bendik Støa Sannes , Henrik Koch

We present an ab initio correlated approach to study molecules that interact strongly with quantum fields in an optical cavity. Quantum electrodynamics coupled cluster theory provides a non-perturbative description of cavity-induced effects…

Chemical Physics · Physics 2020-12-07 Tor S. Haugland , Enrico Ronca , Eirik F. Kjønstad , Angel Rubio , Henrik Koch

We present a microscopic theory of the nonequilibrium nuclear spin dynamics driven by the electron and/or hole under continuous wave pumping in a quantum dot. We show the correlated dynamics of the nuclear spin ensemble and the electron…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 Wen Yang , L. J. Sham

Background: In settings where proof-of-principle trials have succeeded but the effectiveness of different forms of implementation remains uncertain, trials that not only generate information about intervention effects but also provide…

Quantitative Methods · Quantitative Biology 2017-05-16 Guy Harling , Rui Wang , Jukka-Pekka Onnela , Victor De Gruttola

We present two efficient and intruder-free methods for treating dynamic correlation on top of general multi-configuration reference wave functions---including such as obtained by the density matrix renormalization group (DMRG) with large…

Chemical Physics · Physics 2016-09-13 Sandeep Sharma , Gerald Knizia , Sheng Guo , Ali Alavi

Two-parameter perturbation theory is a scheme tailor-made to consistently include nonlinear density contrasts on small scales ($<100\; \mathrm{Mpc}$), whilst retaining a traditional approach to cosmological perturbations in the…

General Relativity and Quantum Cosmology · Physics 2020-03-18 Christopher Gallagher , Timothy Clifton , Chris Clarkson