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We study the open dynamics of a quantum two-level system coupled to an environment modeled by random matrices. Using the quantum channel formalism, we investigate different quantum Markovianity measures and criteria. A thorough analysis of…

Quantum Physics · Physics 2019-10-30 M. Carrera , T. Gorin , C. Pineda

Many electronic systems exhibit striking features in their dynamical response over a prominent range of experimental parameters. While there are empirical suggestions of particular increasing length scales that accompany such transitions,…

Statistical Mechanics · Physics 2015-04-02 Zohar Nussinov , Patrick Johnson , Matthias J. Graf , Alexander V. Balatsky

We present a formalism for studying the behaviour of quantum systems coupled to nonequilibrium environments exhibiting nonGaussian fluctuations. We discuss the role of a qubit as a detector of the statistics of environmental fluctuations,…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Clive Emary

Many advanced quantum techniques feature non-Gaussian dynamics, and the ability to manipulate the system in that domain is the next-stage in many experiments. One example of meaningful non-Gaussian dynamics is that of a double-well…

In the present article, we consider the so-called two-spin equation that describes four-level quantum systems. Recently, these systems attract attention due to their relation to the problem of quantum computation. We study general…

Quantum Physics · Physics 2008-11-26 V. G. Bagrov , M. C. Baldiotti , D. M. Gitman , A. D. Levin

In the geometry of quantum-mechanical processes, the time-varying curvature coefficient of a quantum evolution is specified by the magnitude squared of the covariant derivative of the tangent vector to the state vector. In particular, the…

Quantum Physics · Physics 2025-01-07 Carlo Cafaro , Leonardo Rossetti , Paul M. Alsing

The dynamics is investigated of a free particle on a sphere (rigid rotor or rotator) that is initially in a coherent state. The instability of coherent states with respect to the free evolution leads to nontrivial time-development of…

Quantum Physics · Physics 2013-09-24 K. Kowalski , J. Rembieliński

Quantum circuits -- built from local unitary gates and local measurements -- are a new playground for quantum many-body physics and a tractable setting to explore universal collective phenomena far-from-equilibrium. These models have shed…

Quantum Physics · Physics 2024-01-12 Matthew P. A. Fisher , Vedika Khemani , Adam Nahum , Sagar Vijay

We study and compare the time evolutions of concurrence and quantum discord in a driven system of two interacting qubits prepared in a generic Werner state. The~corresponding quantum dynamics is exactly treated and manifests the appearance…

Quantum Physics · Physics 2020-10-09 Iulia Ghiu , Roberto Grimaudo , Tatiana Mihaescu , Aurelian Isar , Antonino Messina

This paper presents a novel formalism for the out of equilibrium dynamics of the density matrix, capable of describing highly entangled many-body interactions. The evolution of quantum states is evaluated via eigenvalue dynamics of a…

Quantum Physics · Physics 2025-10-28 Mumnuna Aziz Qureshi

Entropy, and its temporal evolution, play a central role in the foundations of quantum theory and in modern quantum technologies. Here we study, in particular, the relations between the --- in general, non-Markovian --- evolution of an open…

Quantum Physics · Physics 2018-09-18 Paolo Aniello , Joonwoo Bae , Dariusz Chruscinski

Under certain conditions, the quantum delta-kicked harmonic oscillator displays quantum resonances. We consider an atom-optical realization of the delta-kicked harmonic oscillator, and present a theoretical discussion of the quantum…

Quantum Physics · Physics 2010-08-03 T. P. Billam , S. A. Gardiner

A direct classical analog of quantum decoherence is introduced. Similarities and differences between decoherence dynamics examined quantum mechanically and classically are exposed via a second-order perturbative treatment and via a strong…

Quantum Physics · Physics 2009-11-07 Jiangbin Gong , Paul Brumer

Quantum Darwinism explains the emergence of a classical description of objects in terms of the creation of many redundant registers in an environment containing their classical information. This amplification phenomenon, where only…

Quantum Physics · Physics 2015-08-12 Gian Luca Giorgi , Fernando Galve , Roberta Zambrini

We consider two interacting systems when one is treated classically while the other system remains quantum. Consistent dynamics of this coupling has been shown to exist, and explored in the context of treating space-time classically. Here,…

Quantum Physics · Physics 2023-12-07 Jonathan Oppenheim , Carlo Sparaciari , Barbara Šoda , Zachary Weller-Davies

We develop a general approach to the nonequilibrium dynamics of quantum impurity systems for arbitrary coupling strength. The numerical renormalization group is used to generate a complete basis set necessary for the correct description of…

Strongly Correlated Electrons · Physics 2007-05-23 Frithjof B. Anders , Avraham Schiller

We study the long time dynamics of quantum spin glasses of rotors using the non-equilibrium Schwinger-Keldysh formalism. These models are known to have a quantum phase transition from a paramagnetic to a spin glass phase, which we approach…

Disordered Systems and Neural Networks · Physics 2009-11-07 Malcolm P. Kennett , Claudio Chamon , Jinwu Ye

The supersymmetric structure of a generalized non-Hermitian driven two-level system is demonstrated. A unitary rotation turns the Hamiltonian into a more convenient form. After decoupling a set of differential equations, the supersymmetric…

Quantum Physics · Physics 2025-10-16 Ivan A. Bocanegra-Garay , Luis M. Nieto

Recently, explicit real time dynamics has been studied in various systems. These quantum mechanical dynamics could provide new recipes in information processing. We study quantum dynamics under time dependent external fields, and explore…

Statistical Mechanics · Physics 2009-01-21 Seiji Miyashita , Shu Tanaka , Hans De Raedt , Bernard Barbara

Quantum states of motion are critical components in the second quantum revolution. We investigate the generation and control of non-Gaussian motional states in a tripartite hybrid quantum system consisting of a collection of qubits coupled…

Quantum Physics · Physics 2025-07-25 Jugal Talukdar , Scott E. Smart , Prineha Narang