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For a quantum many-body system, the direct population of states of double-excitation character is a clear indication that correlations importantly contribute to its nonequilibrium properties. We analyze such correlation-induced transitions…

Strongly Correlated Electrons · Physics 2012-06-25 K. Balzer , S. Hermanns , M. Bonitz

We outline a rigorous method which can be used to solve the many-body Schroedinger equation for a Coulomb interacting electronic system in an external classical magnetic field as well as a quantized electromagnetic field. Effects of the…

Mesoscale and Nanoscale Physics · Physics 2012-10-11 Olafur Jonasson , Chi-Shung Tang , Hsi-Sheng Goan , Andrei Manolescu , Vidar Gudmundsson

In this study, we combine the ab initio Migdal-Eliashberg approach with the intermediate representation for the Green's function, enabling accurate and efficient calculations of the momentum-dependent superconducting gap function while…

Superconductivity · Physics 2025-05-15 Hitoshi Mori , Takuya Nomoto , Ryotaro Arita , Elena R. Margine

The accurate ab initio simulation of molecules and periodic solids with diagrammatic perturbation theory is an important task in quantum chemistry, condensed matter physics, and materials science. In this article, we present the…

In this work we present a numerical method to solve the set of Dyson-like equations arising the context of non-equilibrium Green's functions. The technique is based on the self-consistent solution of the Dyson equations for the interacting…

Strongly Correlated Electrons · Physics 2019-09-04 N. W. Talarico , S. Maniscalco , N. Lo Gullo

We examine the quasiparticle lifetime and spectral weight near the Fermi surface in the two-dimensional Hubbard model. We use the FLEX approximation to self-consistently generate the Matsubara Green's functions and then we analytically…

Strongly Correlated Electrons · Physics 2007-05-23 William H. Beere , James F. Annett

We provide a mathematical analysis of the Dynamical Mean-Field Theory, a celebrated representative of a class of approximations in quantum mechanics known as embedding methods. We start by a pedagogical and self-contained mathematical…

Mathematical Physics · Physics 2024-06-06 Éric Cancès , Alfred Kirsch , Solal Perrin-Roussel

A many-body theory based on nonequilibrium Green functions, in which transport and optics are treated on a microscopic quantum mechanical basis, is used to compute gain and absorption in the optical and THz regimes in quantum cascade laser…

Other Condensed Matter · Physics 2009-11-10 M. F. Pereira , S. -C. Lee , A. Wacker

The performance of many-body perturbation theory for calculating ground-state properties is investigated. We present fully numerical results for the electron gas in three and two dimensions in the framework of the GW approximation. The…

Condensed Matter · Physics 2009-10-31 P. Garcia-Gonzalez , R. W. Godby

The recently derived Fourier--Matsubara expansion of imaginary--time correlation functions comprises an exact result of linear response theory for finite-temperature quantum many-body systems. In its density--density version, the expansion…

In this article, we investigate the thermal properties of non-relativistic many-body systems at finite temperature and chemical potential. We compute the one-point function of various operators constructed out of the basic fields in ideal…

High Energy Physics - Theory · Physics 2025-03-11 Rajesh Kumar Gupta , Meenu

We apply reduced density-matrix functional theory to the parabolically confined quantum Hall droplet in the spin-frozen strong magnetic field regime. One-body reduced density matrix functional method performs remarkably well in obtaining…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 E. Tölö , A. Harju

A method for deriving quantum kinetic equations with initial correlations is developed on the basis of the nonequilibrium Green's function formalism. The method is applicable to a wide range of correlated initial states described by…

Statistical Mechanics · Physics 2009-10-31 V. G. Morozov , G. Röpke

We present a calculation of the spectral properties of a single charge doped at a Cu($3d$) site of the Cu-F plane in KCuF$_{3}$. The problem is treated by generating the equations of motion for the Green's function by means of subsequent…

Strongly Correlated Electrons · Physics 2016-12-26 Krzysztof Bieniasz , Mona Berciu , Andrzej M. Oleś

Single-particle resonances in the continuum are crucial for studies of exotic nuclei. In this study, the Green's function approach is employed to search for single-particle resonances based on the relativistic-mean-field model. Taking…

Nuclear Theory · Physics 2021-05-11 Ya-Tian Wang , Ting-Ting Sun

One-body Green's function theories implemented on the real frequency axis offer a natural formalism for the unbiased theoretical determination of quasiparticle spectra in molecules and solids. Self-consistent Green's function methods…

Computational Physics · Physics 2015-05-22 Alicia Rae Welden , Jordan J. Phillips , Dominika Zgid

We reduce two-body problem to the one-body problem in general case of deformed Heisenberg algebra leading to minimal length.Two-body problems with delta and Coulomb-like interactions are solved exactly. We obtain analytical expression for…

Quantum Physics · Physics 2018-01-17 M. I. Samar , V. M. Tkachuk

We develop a Green's function approach to quasiparticle excitations of open-shell systems within the GW approximation. It is shown that accurate calculations of the characteristic multiplet structure require a precise knowledge of the self…

Materials Science · Physics 2014-09-11 Johannes Lischner , Jack Deslippe , Manish Jain , Steven G. Louie

The energy dissipation and heat flows associated with the particle current in a system with a molecular junction are considered. In this connection, we determine the effective temperature of the molecular oscillator that is compatible with…

Mesoscale and Nanoscale Physics · Physics 2018-03-20 Jan Loos , Thomas Koch , Holger Fehske

The quantum mechanical many-body problem is rarely analytically solvable. One notable exception is the case of two electrons interacting via a Coulomb potential in a uniform magnetic field. The motion is confined to a two-dimensional plane,…

Mesoscale and Nanoscale Physics · Physics 2011-01-04 Tobias Kramer