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A general and in principle exact approach for the continuous variable entanglement in a system of coupled harmonic oscillators in contact with a thermal bath is formulated. This allows a generalization to describe entanglement's existence…

Quantum Physics · Physics 2016-07-26 Danyer Pérez Adán , Fernando Guzmán Martinez , Oscar Rodríguez Hoyos

With a choice of boundary conditions for solutions of the Schr\"odinger equation, state vectors and density operators even for closed systems evolve asymmetrically in time. For open systems, standard quantum mechanics consequently predicts…

Quantum Physics · Physics 2010-05-25 P. W. Bryant

In this paper, we introduce quantile coherency to measure general dependence structures emerging in the joint distribution in the frequency domain and argue that this type of dependence is natural for economic time series but remains…

Statistics Theory · Mathematics 2018-12-31 Jozef Baruník , Tobias Kley

The uncertainty principle, which bounds the uncertainties involved in obtaining precise outcomes for two complementary variables defining a quantum particle, is a crucial aspect in quantum mechanics. Recently, the uncertainty principle in…

Quantum Physics · Physics 2012-04-24 Chuan-Feng Li , Jin-Shi Xu , Xiao-Ye Xu , Ke Li , Guang-Can Guo

The nonequilibrium dynamics of coupled quantum oscillators subject to different time dependent quenches are analyzed in the context of the Liouville-von Neumann approach. We consider models of quantum oscillators in interaction that are…

High Energy Physics - Theory · Physics 2009-11-07 G. Flores-Hidalgo , Rudnei O. Ramos

Based on the relative entropy, we give a unified characterization of quantum correlations for nonlocality, steerability, discord and entanglement for any bipartite quantum states. For two-qubit states we show that the quantities obtained…

Quantum Physics · Physics 2017-04-14 Tinggui Zhang , Hong Yang , Xianqing Li-Jost , Shao-Ming Fei

Consider a discrete-time quantum walk on the $N$-cycle subject to decoherence both on the coin and the position degrees of freedom. By examining the evolution of the density matrix of the system, we derive some new conclusions about the…

Quantum Physics · Physics 2011-07-20 Chaobin Liu , Nelson Petulante

We address the problem of determining whether or not a harmonic oscillator has been perturbed by an external force. Quantum detection and estimation theory has been used in devising optimum measurement schemes. Detection probability has…

Quantum Physics · Physics 2015-06-26 Matteo G. A. Paris

By collecting both quantum and gravitational principles, a space-time uncertainty relation $(\delta t)(\delta r)^{3}\geqslant\pi r^{2}l_{p}^{2}$ is derived. It can be used to facilitate the discussion of several profound questions, such as…

High Energy Physics - Theory · Physics 2008-11-07 Yi-Xin Chen , Yong Xiao

Based on the Pauli spin operators we develop the notion of the spin-correlation matrix for the two-qubit system. If this matrix is non-zero, the measure of the correlation between the qubits is the average of the non-zero elements.…

Quantum Physics · Physics 2012-04-03 Faisal A. A. El-Orany

The development and improvement of analytical methods for evaluating nonclassical correlations is one of the most important tasks in quantum information science. In this paper, we investigate a mixed spin-$(1/2,S)$ system with an arbitrary…

Quantum Physics · Physics 2025-06-06 Saeed Haddadi , Elena I. Kuznetsova , M. A. Yurischev

The degrees of quantum coherence of cosmological perturbations of different spins are computed in the large-scale limit and compared with the standard results holding for a single mode of the electromagnetic field in an optical cavity. The…

General Relativity and Quantum Cosmology · Physics 2017-11-09 Massimo Giovannini

The time evolution of the correlation functions of an ensemble of anharmonic N-component oscillators with O(N) symmetry is described by a flow equation, exact up to corrections of order $1/N^2$. We find effective irreversibility.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Luis M. A. Bettencourt , C. Wetterich

Coupled oscillators are among the simplest composite quantum systems in which the interplay of entanglement and interaction may be explored. We examine the effects of coupling on fluctuations of the coordinates and momenta of the…

Quantum Physics · Physics 2021-05-18 Roberto Baginski B. Santos , Vinicius S. F. Lisboa

It is shown that quantum uncertainty of motion in systems controlled mainly by gravity generally grows with orbital timescale $H^{-1}$, and dominates classical motion for trajectories separated by distances less than $\approx H^{-3/5}$ in…

General Relativity and Quantum Cosmology · Physics 2014-04-17 Craig J. Hogan

We consider quantum batteries given by composite interacting quantum systems in terms of the thermodynamic work cost of local random unitary processes. We characterize quantum correlations by monitoring the average energy change and its…

Quantum Physics · Physics 2026-03-30 Satoya Imai , Otfried Gühne , Stefan Nimmrichter

The paper deals with the problem of open systems out of equilibrium. An analytical expression for time-dependent density matrix of two arbitrary coupled identical quantum oscillators interacting with separate reservoirs is derived using…

Quantum Physics · Physics 2014-12-16 Illarion Dorofeyev

It is shown, by considering the case of the harmonic oscillator, that quantum fluctuations may be the most significant contribution to the random walk of a single molecule. From this point, the controversy on the existence of a standard…

Quantum Physics · Physics 2010-01-05 Jean Paul Mbelek

Precision control of a quantum system requires accurate determination of the effective system Hamiltonian. We develop a method for estimating the Hamiltonian parameters for some unknown two-state system and providing uncertainty bounds on…

In quantum/wave systems with chaotic classical analogs, wavefunctions evolve in highly complex, yet deterministic ways. A slight perturbation of the system, though, will cause the evolution to diverge from its original behavior increasingly…

Chaotic Dynamics · Physics 2009-11-07 Nicholas R. Cerruti , Steven Tomsovic