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We study the ground-state properties of a two-component fermionic mixture effectively confined in a one-dimensional harmonic trap. We consider scenarios when numbers of particles in components are the same but particles have different…

Quantum Gases · Physics 2020-03-10 Patrycja Łydżba , Tomasz Sowiński

Recent work has proposed fading ergodicity as a mechanism for many-body ergodicity breaking. Here, we show that two paradigmatic random matrix ensembles -- the Rosenzweig-Porter model and the ultrametric model -- fall within the same…

Statistical Mechanics · Physics 2026-03-26 Rafał Świętek , Maksymilian Kliczkowski , Miroslav Hopjan , Lev Vidmar

In a recent Letter [Phys. Rev. Lett. 125, 180604 (2020)], we introduced a closed-form analytic expression for the average bipartite von Neumann entanglement entropy of many-body eigenstates of random quadratic Hamiltonians. Namely, of…

Statistical Mechanics · Physics 2021-07-12 Patrycja Łydżba , Marcos Rigol , Lev Vidmar

The concept of fidelity decay is discussed from the point of view of the scattering matrix, and the scattering fidelity is introduced as the parametric cross-correlation of a given S-matrix element, taken in the time domain, normalized by…

Chaotic Dynamics · Physics 2009-11-11 R. Schaefer , T. Gorin , T. H. Seligman , H. -J. Stoeckmann

A local excitation in a quantum many-spin system evolves deterministically. A time-reversal procedure, involving the inversion of the signs of every energy and interaction, should produce the excitation revival. This idea, experimentally…

Quantum Physics · Physics 2016-05-23 Pablo R. Zangara , Denise Bendersky , Patricia R. Levstein , Horacio M. Pastawski

According to the quantum chaos paradigm, the nature of a system's classical dynamics, whether integrable or chaotic, is universally reflected in the fluctuations of its quantum spectrum. However, since many-body spectra in the mean field…

Quantum Gases · Physics 2025-10-14 Georg Maier , Carolyn Echter , Juan Diego Urbina , Caio Lewenkopf , Klaus Richter

In a recent paper (arXiv:1905.07348v1), Dyson scheme to deal with density matrix of non-Hermitian Hamiltonians has been used to investigate the entanglement of states of a PT-symmetric bosonic system. They found that von Neumann entropy can…

Quantum Physics · Physics 2020-10-20 C. A. Goulart , M. P. Pato

Symmetry implications for the decoherence of quantum oscillations of a two-state system in a solid are studied. When the oscillation frequency is small compared to the Debye frequency, the universal lower bound on the decoherence due to the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Eugene M. Chudnovsky

We examine two exactly solvable models of decoherence -- a central spin-system, (i) with and (ii) without a self--Hamiltonian, interacting with a collection of environment spins. In the absence of a self--Hamiltonian we show that in this…

Quantum Physics · Physics 2009-11-11 F. M. Cucchietti , J. P. Paz , W. H. Zurek

We study numerically the properties of entanglement of two interacting, or noninteracting, particles evolving in a regime of quantum chaos in the quantum Chirikov standard map. Such pairs can be viewed as interacting, on noninteracting,…

Quantum Physics · Physics 2022-05-20 Leonardo Ermann , Klaus M. Frahm , Dima L Shepelyansky

Tensor networks provide discrete representations of quantum many-body systems, yet their precise connection to continuum field theories remains relatively poorly understood. Invoking a notion of typicality, we develop a continuum…

Disordered Systems and Neural Networks · Physics 2026-04-09 Maksimilian Usoltcev , Carolin Wille , Jens Eisert , Alexander Altland

This paper presents a unified semiclassical framework for five regimes of quantum fidelity decay and conjectures a new universal regime. The theory is based solely on the statistics of actions in the dephasing representation.…

Quantum Physics · Physics 2007-05-23 Jiri Vanicek

We introduce a scheme for the quantum simulation of many-body decoherence based on the unitary evolution of a stochastic Hamiltonian. Modulating the strength of the interactions with stochastic processes, we show that the noise-averaged…

Quantum Physics · Physics 2017-04-07 Aurélia Chenu , Mathieu Beau , Jianshu Cao , Adolfo del Campo

Evaluating the role of perturbations versus the intrinsic coherent dynamics in driving to equilibrium is of fundamental interest to understand quantum many-body thermalization, in the quest to build ever complex quantum devices. Here we…

The transition from a few-body system to a many-body system can result in new length scales, novel collective phenomena or even in a phase transition. Such a threshold behavior was shown for example in 4He droplets, where 4He turns into a…

We develop a master equation formalism to describe the evolution of the average density matrix of a closed quantum system driven by a stochastic Hamiltonian. The average over random processes generally results in decoherence effects in…

Quantum Physics · Physics 2011-11-30 Li Yu , Daniel F. V. James

We discuss the decay rates of chaotic quantum systems coupled to noise. We model both the Hamiltonian and the system-noise coupling by random $N \times N$ Hermitian matrices, and study the spectral properties of the resulting Lindblad…

Quantum Physics · Physics 2019-12-11 Tankut Can , Vadim Oganesyan , Dror Orgad , Sarang Gopalakrishnan

Scattering on a resonance state coupled to a complicated background is a typical problem for mesoscopic quantum many-body systems as well as for wave propagation in the presence of a complex environment. On average, such a simple mode…

Mesoscale and Nanoscale Physics · Physics 2020-03-09 Dmitry V. Savin

We numerically investigate statistical ensembles for the occupations of eigenstates of an isolated quantum system emerging as a result of quantum quenches. The systems investigated are sparse random matrix Hamiltonians and disordered…

Statistical Mechanics · Physics 2012-09-14 Fabian Kolley , Oriol Bohigas , Boris V. Fine

The relativistic mean-field theory provides a framework in which the nuclear many-body problem is described as a self-consistent system of nucleons and mesons. In the mean-field approximation, the self-consistent time evolution of the…

Nuclear Theory · Physics 2007-05-23 Dario Vretenar