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Related papers: Generalized One-Particle Density Matrices and Quas…

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A random matrix ensemble incorporating both GUE and Poisson level statistics while respecting $U(N)$ invariance is proposed and shown to be equivalent to a system of noninteracting, confined, one dimensional fermions at finite temperature.

Condensed Matter · Physics 2009-10-22 Moshe Moshe , Herbert Neuberger , Boris Shapiro

We study the fermionic non-Gaussianity in typical quantum states, focusing on Haar random states of qubits with or without a global $U(1)$ symmetry. Using the Weingarten calculus, we derive analytical predictions for the non-Gaussianity,…

Statistical Mechanics · Physics 2026-05-20 Filiberto Ares , Sara Murciano , Pasquale Calabrese

We establish one-body reduced density-matrix functional theory for the canonical ensemble in a finite basis set at an elevated temperature. Including temperature guarantees differentiability of the universal functional by occupying all…

Mathematical Physics · Physics 2023-02-22 Sarina M. Sutter , Klaas J. H. Giesbertz

We consider a dilute homogeneous mixture of bosons and spin-polarized fermions at zero temperature. We first construct the formal scheme for carrying out systematic perturbation theory in terms of single particle Green's functions. We…

Condensed Matter · Physics 2009-11-07 Alexander P. Albus , Simon A. Gardiner , Fabrizio Illuminati , Martin Wilkens

We present a new variational method for investigating the ground state and out of equilibrium dynamics of quantum many-body bosonic and fermionic systems. Our approach is based on constructing variational wavefunctions which extend Gaussian…

Quantum Physics · Physics 2018-03-14 Tao Shi , Eugene Demler , J. Ignacio Cirac

In this paper we provide a novel and general way to construct the result of the action of any bosonic or fermionic operator represented in second quantized form on a state vector, without resorting to the matrix representation of operators…

Quantum Physics · Physics 2010-03-09 Alexej I. Streltsov , Ofir E. Alon , Lorenz S. Cederbaum

We provide a brief overview of approaches for calculating the density of states of quantum systems and random matrix Hamiltonians using the tools of free probability theory. For a given Hamiltonian of a quantum system or a generic random…

Quantum Physics · Physics 2025-12-04 Keun-Young Kim , Kuntal Pal

We consider the relation between three different approaches to defining quantum states across several times and locations: the pseudo-density matrix (PDM), the process matrix, and the multiple-time state approaches. Previous studies have…

Quantum Physics · Physics 2024-03-14 Xiangjing Liu , Zhian Jia , Yixian Qiu , Fei Li , Oscar Dahlsten

We consider the insertion of integrable boundaries for a class of supersymmetric quantum models. The generic conditions for constructing purely bosonic, purely fermionic or mixed type solutions of the graded reflection equation are…

Mathematical Physics · Physics 2013-11-19 Nikos Karaiskos

The one-particle density matrices for hard core bosons in a one-dimensional harmonic trap are computed numerically for systems with up to 160 bosons. Diagonalization of the density matrix shows that the many-body ground state is not…

Soft Condensed Matter · Physics 2007-05-23 T. Papenbrock

Based on a generalization of Hohenberg-Kohn's theorem, we propose a ground state theory for bosonic quantum systems. Since it involves the one-particle reduced density matrix $\gamma$ as a natural variable but still recovers quantum…

One plus two-body embedded Gaussian orthogonal ensemble of random matrices with parity [EGOE(1+2)-$\pi$] generated by a random two-body interaction (modeled by GOE in two particle spaces) in the presence of a mean-field, for spinless…

Nuclear Theory · Physics 2011-06-24 Manan Vyas , V. K. B. Kota , P. C. Srivastava

We present a novel analytical approach for the calculation of the mean density of states in many-body systems made of confined indistinguishable and non-interacting particles. Our method makes explicit the intrinsic geometry inherent in the…

Quantum Physics · Physics 2013-12-18 Quirin Hummel , Juan Diego Urbina , Klaus Richter

Recently a procedure by generalized density matrix (GDM) is proposed for calculating a collective/bosonic Hamiltonian microscopically from the shell-model Hamiltonian. In this work we examine the validity of the method by comparing the GDM…

Nuclear Theory · Physics 2015-06-04 L. Y. Jia , V. G. Zelevinsky

We give a detailed discussion of the recently developed Generalized Dynamical Mean-Field Theory (GDMFT) for a mixture of bosonic and fermionic particles. We show that this method is non-perturbative and exact in infinite dimensions and…

Other Condensed Matter · Physics 2009-04-07 I. Titvinidze , M. Snoek , W. Hofstetter

For configurational space of arbitrary dimension a strict form of the uncertainty principle has been obtained, which takes into account the dependence of inequality limit on the effective number of pure states present in given statistical…

Quantum Physics · Physics 2009-11-06 M. U. Karelin , A. M. Lazaruk

We solve the time evolution of the density matrix both for fermions and bosons in the presence of a homogeneous but time dependent external electric field. The number of particles produced by the external field, as well as their…

High Energy Physics - Theory · Physics 2009-10-28 Joakim Hallin , Per Liljenberg

The $N$-representability problem is the problem of determining whether or not there exists $N$-particle states with some prescribed property. Here we report an affirmative solution to the fermion $N$-representability problem when both the…

Mathematical Physics · Physics 2015-06-17 Erik Tellgren , Simen Kvaal , Trygve Helgaker

We investigate analytically and numerically a random-matrix model for m fermions occupying l1 single-particle states with positive parity and l2 single-particle states with negative parity and interacting through random two-body forces that…

Nuclear Theory · Physics 2008-11-26 T. Papenbrock , H. A. Weidenmueller

A fermion ground state energy functional is set up in terms of particle density, relative pair density, and kinetic energy tensor density. It satisfies a minimum principle if constrained by a complete set of compatibility conditions. A…

Chemical Physics · Physics 2009-10-17 Bin Liu , Jerome K. Percus