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Some unexplored decoherence aspects within the Caldeira-Leggett master equation are analyzed and discussed. The decoherence process is controlled by the two environment parameters, the relaxation rate or friction and the temperature,…

Quantum Physics · Physics 2022-07-04 S. V. Mousavi , S. Miret-Artes

We study a model of dephasing (decoherence) in a two-state quantum system (qubit) coupled to a bath of harmonic oscillators. An exact analytic solution for the reduced dynamics of a two-state system in this model has been obtained…

Quantum Physics · Physics 2015-05-28 V. G. Morozov , S. Mathey , G. Röpke

Decoherence originates from the leakage of quantum information into external degrees of freedom. For a qubit the two main decoherence channels are relaxation and dephasing. Here, we report an experiment on a superconducting qubit where we…

Quantum Physics · Physics 2018-07-16 Q. Ficheux , S. Jezouin , Z. Leghtas , B. Huard

We consider the interaction of a quantum system (spin-1/2) with a macroscopic quantum apparatus (harmonic oscillator) which in turn is coupled to a bath of harmonic oscillators. Exact solutions of the Markovian Master equation show that the…

Quantum Physics · Physics 2009-10-31 Anu Venugopalan

We discuss fluctuations in the measurement process and how these fluctuations are related to the dissipational parameter characterising quantum damping or decoherence. On the example of the measuring current of the variable-barrier or QPC…

Quantum Physics · Physics 2008-11-26 L. Stodolsky

Recently a model of metric fluctuations has been proposed which yields an effective Schr\"odinger equation for a quantum particle with a modified inertial mass, leading to a violation of the weak equivalence principle. The renormalization…

General Relativity and Quantum Cosmology · Physics 2015-06-26 H. -P. Breuer , E. Göklü , C. Lämmerzahl

According to the eigenstate thermalization ansatz, matrices representing generic few body observables take on a specific form when displayed in the eigenbasis of a chaotic Hamiltonian. We examine the effect of environmental induced…

Quantum Physics · Physics 2019-03-06 Lars Knipschild , Jochen Gemmer

Environment--induced decoherence causes entropy increase. It can be quantified using, e.g., the purity $\varsigma={\rm Tr}\rho^2$. When the Hamiltonian of a quantum system is perturbed, its sensitivity to such perturbation can be measured…

Quantum Physics · Physics 2009-11-10 F. M. Cucchietti , D. A. R. Dalvit , J. P. Paz , W. H. Zurek

We point out that even at the absolute zero of temperature environmental decoherence limits the destructive interference between time-reversed paths for an electron in a disordered metal, and thus causes the leading (`weak localization')…

Condensed Matter · Physics 2008-02-03 Maxim Vavilov , Vinay Ambegaokar

The purpose of the present study is to derive the pointer states of a macroscopic system interacting with its environment, under the general assumptions, i.e., without assuming any form of the interaction Hamiltonian. The lowest order…

Quantum Physics · Physics 2014-04-18 Kentaro Urasaki

The present letter finds the complete set of exact solutions of the time-dependent generalized Cini model by making use of the Lewis-Riesenfeld invariant theory and the invariant-related unitary transformation formulation and, based on…

Quantum Physics · Physics 2007-05-23 Jian Qi Shen , San Shui Xiao , Qiang Wu

The dynamics of a dimer coupled to two different environments each in a spin star configuration under the influence of decoherence is studied. The exact analytical expression for the transition probability in the dimer system is obtained…

Quantum Physics · Physics 2014-01-15 I. Sinayskiy , A. Marais , F. Petruccione , A. Ekert

A direct classical analog of the quantum dynamics of intrinsic decoherence in Hamiltonian systems, characterized by the time dependence of the linear entropy of the reduced density operator, is introduced. The similarities and differences…

Quantum Physics · Physics 2009-11-10 Jiangbin Gong , Paul Brumer

We review the difference between standard environmental decoherence and 'intrinsic decoherence', which is taken to be an ineluctable process of Nature. Environmental decoherence is typically modeled by spin bath or oscillator modes - we…

General Relativity and Quantum Cosmology · Physics 2015-06-05 P. C. E. Stamp

We propose a simple phenomenological model to estimate the spatial decoherence time in quantum dots. The dissipative phase space dynamics is described in terms of the density matrix and the corresponding Wigner function, which are derived…

Other Condensed Matter · Physics 2010-05-05 Michael Genkin , Erik Waltersson , Eva Lindroth

We consider a finite-dimensional quantum system coupled to a thermal reservoir and subject to a time-periodic, energy conserving forcing. We show that, if a certain dynamical decoupling condition is fulfilled, then the periodic forcing…

Quantum Physics · Physics 2014-02-27 Volker Bach , Walter de Siqueira Pedra , Marco Merkli , Israel Michael Sigal

In quantum information theory, quantum discord has been proposed as a tool to characterise the presence of "quantum correlations" between the subparts of a given system. Whether a system behaves quantum-mechanically or classically is…

Quantum Physics · Physics 2022-10-20 Jerome Martin , Amaury Micheli , Vincent Vennin

We study a simplified Heisenberg spin model in order to clarify the idea of decoherence in closed quantum systems. For this purpose, we define a new concept: the decoherence function \Xi(t), which describes the dynamics of decoherence in…

Quantum Physics · Physics 2007-05-23 Olavi Dannenberg

Coherence evolution and echo effect of an electron spin, which is coupled inhomogeneously to an interacting one-dimensional finite spin bath via hyperfine-type interaction, is studied using the adaptive time dependent density matrix…

Mesoscale and Nanoscale Physics · Physics 2008-09-19 Zhi-Hui Wang , Bing-Shen Wang , Zhao-Bin Su

We propose a nonextensive generalization (q parametrized) of the von Neumann equation for the density operator. Our model naturally leads to the phenomenon of decoherence, and unitary evolution is recovered in the limit of q -> 1. The…

Quantum Physics · Physics 2013-03-13 A. Vidiella-Barranco , H. Moya-Cessa
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