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We introduce a quasiclassical Green function approach describing the unitary yet irreversible dynamics of quantum systems effectively acting as their own environment. Combining a variety of concepts of quantum many-body theory, notably the…

Mesoscale and Nanoscale Physics · Physics 2025-09-09 Alexander Altland , Kun Woo Kim , Tobias Micklitz

Correlations between different partitions of quantum systems play a central role in a variety of many-body quantum systems, and they have been studied exhaustively in experimental and theoretical research. Here, we investigate dynamical…

We present a novel hybrid quantum/classical (QM/MM) approach to the calculation of charged excitations in molecular solids based on the many-body Green's function $GW$ formalism. Molecules described at the $GW$ level are embedded into the…

Chemical Physics · Physics 2018-02-14 Jing Li , Gabriele D'Avino , Ivan Duchemin , David Beljonne , Xavier Blase

The configuration interaction (CI) is a versatile wavefunction theory for interacting fermions but it involves an extremely long CI series. Using a symmetric tensor decomposition (STD) method, we convert the CI series into a compact and…

Chemical Physics · Physics 2013-05-30 Wataru Uemura , Osamu Sugino

We derive the quantum thermodynamics of quantum Brownian motion from the exact solution of its reduced density matrix. We start from the total equilibrium thermal state between the Brownian particle and its reservoir, and solve analytically…

Quantum Physics · Physics 2024-07-09 Chuan-Zhe Yao , Wei-Min Zhang

We present the diagrammatic theory of the irreducible self-energy and Bethe-Salpeter kernel that naturally arises within the Green's function formalism for a general $N$-body non-hermitian interaction. In this work, we focus specifically on…

Strongly Correlated Electrons · Physics 2026-01-23 Christopher J. N. Coveney , David P. Tew

A variational formulation for the calculation of interacting fermion systems based on the density-matrix functional theory is presented. Our formalism provides for a natural integration of explicit many-particle effects into standard…

Strongly Correlated Electrons · Physics 2013-05-29 Peter E. Bloechl , Christian F. J. Walther , Thomas Pruschke

This work develops and illustrates a new method of calculating "chemically accurate" electronic wavefunctions (and energies) via a truncated full configuration interaction (CI) procedure which arguably circumvents the large matrix…

Chemical Physics · Physics 2022-12-21 Stephen J. Cotton

Collective many-body dynamics for time-dependent quantum Hamiltonian functions is investigated for a dynamical system that exhibits multiple degrees of freedom, in this case a combined (Paul and Penning) trap. Quantum stability is…

Quantum Physics · Physics 2022-08-19 Bogdan M. Mihalcea

Background: Ab initio many-body methods have been developed over the past ten years to address mid-mass nuclei... As progress in the design of inter-nucleon interactions is made, further efforts must be made to tailor many-body methods.…

Nuclear Theory · Physics 2017-02-01 J. Ripoche , D. Lacroix , D. Gambacurta , J. -P. Ebran , T. Duguet

We present an efficient \textit{ab initio} algorithm for quantum dynamics simulations of interacting systems that is based on the conditional decomposition of the many-body wavefunction [Phys. Rev. Lett. 113, 083003 (2014)]. Starting with…

Mesoscale and Nanoscale Physics · Physics 2019-02-27 Guillermo Albareda , Aaron Kelly , Angel Rubio

Enhancing interactions in many-body quantum systems, while protecting them from environmental decoherence, is at the heart of many quantum technologies. Waveguide quantum electrodynamics is a promising platform for achieving this, as it…

Quantum Physics · Physics 2024-05-31 Aviv Karnieli , Offek Tziperman , Charles Roques-Carmes , Shanhui Fan

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…

The transport properties of junctions composed of a central region tunnel-coupled to external electrodes are frequently studied within the single-impurity Anderson model with Hubbard on-site interaction. In the present work, we supplement…

Mesoscale and Nanoscale Physics · Physics 2021-10-05 Ulrich Eckern , Karol I. Wysokiński

We present a method which computes many-electron energies and eigenfunctions by a full configuration interaction which uses a basis of atomistic tight-binding wave functions. This approach captures electron correlation as well as atomistic…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Erik Nielsen , Rajib Rahman , Richard P. Muller

We relate the quantum dynamics of the Bose-Hubbard model (BHM) to the semiclassical nonlinear equations that describe an array of interacting Bose condensates by implementing a standard variational procedure based on the coherent state…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 R. Franzosi , V. Penna , R. Zecchina

We present the multi-channel Dyson equation that combines two or more many-body Green's functions to describe the electronic structure of materials. In this work we use it to model photoemission spectra by coupling the one-body Green's…

Strongly Correlated Electrons · Physics 2023-10-03 Gabriele Riva , Pina Romaniello , J. Arjan Berger

We propose a method to incorporate the coupling between shape and pairing collective degrees of freedom in the framework of the interacting boson model (IBM), based on the nuclear density functional theory. To account for pairing…

Nuclear Theory · Physics 2020-11-18 K. Nomura , D. Vretenar , Z. P. Li , J. Xiang

Quantum correlations can be used as a resource for quantum computing, eg for quantum state manipulation, and for quantum sensing, eg for creating non-classical states which allow to achieve the quantum advantage regime. This review collects…

Quantum Gases · Physics 2023-02-14 Anna Minguzzi , Patrizia Vignolo

We use the system-plus-reservoir approach to study the quantum dynamics of a bipartite continuous variable system (two generic particles). We present an extension of the traditional model of a bath of oscillators which is capable of…

Quantum Physics · Physics 2015-05-13 O. S. Duarte , A. O. Caldeira