arXiv:quant-ph/0601025

Decoherence and localization in tunneling process under influence of one external degree of freedom

Quanlin Jie, Bambi Hu, Guangjong Dong

Published Jan 4, 2006• 0 citations

Abstract

We investigate numerically the tunneling effect under influence of another particle in a double well system. Such influence from only one degree of freedom makes decoherence and quantum-classical transition, i.e., suppression of the tunneling effect. The decoherence happens even for cases that the influence is from a particle of very small mass, and it has virtually no effect in the corresponding classical dynamics. There are cases similar to dynamical localization that the suppressed tunneling rate is several times smaller than the classical counterpart. This result is relevant for understanding quantitatively the dynamical process of decoherence and quantum to classical transition.

DOI: 10.48550/arxiv.quant-ph/0601025

Related papers

Decoherence by a classically small influence

Wen-Lei Zhao, Jianzhong Wang, Dou Fu-Quan

Via a system of two kicked particles that are coupled in an infinite square well, we numerically show that the interaction with a particle of very small mass is able to lead to a quantum-to-classical transition on condition that the corresponding classical dynamics is almost unaffected. With the decrease of the mass of one of the particles, its effect on the classical dynamics of the other one decreases. Such an effect is even negligible if the mass of the particle is small enough. The classically chaotic dynamics of this small particle is effective for promoting the decoherence of the heavy particle. Therefore its quantum behavior exhibits the transition from the dynamical localization to the classically chaotic diffusion with the decrease of the effective Planck's constant ħ. Under the perturbation from the small particle, the linear entropy is rapidly saturated as time passes by. With the decrease of ħ, the time-averaged linear entropy exponentially increases from zero to almost unity.

Acta Physica SinicaJan 1, 20123 citations

Quantum to classical transition induced by a classically small influence*

Wen-Lei Zhao, Quanlin Jie

We investigate the quantum to classical transition induced by two-particle interaction via a system of periodically kicked particles. The classical dynamics of particle 1 is almost unaffected in condition that its mass is much larger than that of particle 2. Interestingly, such classically weak influence leads to the quantum to classical transition of the dynamical behavior of particle 1. Namely, the quantum diffusion of this particle undergoes the transition from dynamical localization to the classically chaotic diffusion with the decrease of the effective Planck constant ℏ eff. The behind physics is due to the growth of entanglement in the system. The classically very weak interaction leads to the exponential decay of purity in condition that the classical dynamics of external degrees freedom is strongly chaotic.

Chinese Physics BApr 17, 20207 citations

Decoherence, tunneling, and noise-induced activation in a double-potential well at high and zero temperature

Nuno D. Antunes, Fernando C. Lombardo, Diana Monteoliva +1 more

We study the effects of the environment on tunneling in an open system described by a static double-well potential. We describe the evolution of a quantum state localized in one of the minima of the potential at t = 0, in both the limits of high and zero environment temperature. We show that the evolution of the system can be summarized in terms of three main physical phenomena--namely, decoherence, quantum tunneling, and noise-induced activation--and we obtain analytical estimates for the corresponding time scales. These analytical predictions are confirmed by large-scale numerical simulations, providing a detailed picture of the main stages of the evolution and of the relevant dynamical processes.

arXiv:quant-ph/0508036Physical Review EJun 2, 200623 citations

Macroscopic tunneling, decoherence and noise-induced activation

Fernando C. Lombardo, Diana Monteoliva, Paula I. Villar

Abstract. We study the effects of the environment at zero temperature on tunneling in an open system described by a static double-well potential. We show that the evolution of the system in an initial Schrödinger cat state, can be summarized in terms of three main physical phenomena, namely decoherence, quantum tunneling and noise-induced activation. Using large-scale numerical simulations, we obtain a detailed picture of the main stages of the evolution and of the relevant dynamical processes. The tunneling of a particle through a potential barrier is a fundamental effect in quantum mechanics. Macroscopic quantum tunneling can be associated with the tunneling of a many-body wavefunction through a potential barrier, and therefore provides a more stringent test of the validity of quantum mechanics than one particle case. One place where the study of macroscopic quantum tunneling is experimentally accesible is in the tunneling of a Bose-Einstein condensate (BEC) out of an optical trap. These systems have a controllable number of atoms and hence straddle the boundary between microscopic and macroscopic, and hence between quantum and classical systems. Proposals to perform interference experiments using confined atoms

Jan 1, 20061 citation

AC-Control of Single Particle Tunneling

E. Kierig

The aim to control the internal and external degrees of freedom of quantum systems is of great interest for many fields of physics and chemistry. One opportunity to realize such a coherent control is provided by strong, time depended, external fields. In this work the experimental realization of a model-system is presented. The coherent control of the tunneling dynamics of single atoms by means of a time-periodic, external field is demonstrated. Depending on the parameters of the driving force the tunneling rate can be varied up to a total suppression of the tunneling process in the extreme. This type of dynamical localization is known as "coherent destruction of tunneling". The experimental setup allows a direct access to the tunneling dynamics of single atoms in a double well structure and enables great freedom concerning the parameters. Not only the double well potential, the driving frequency and the driving amplitude can be varied, but also the temporal and spatial symmetry of the driving. A coherent beam of slow, metastable argon atoms serves as source of particles, which can be detected spatially resolved enabling the direct observation of the tunneling dynamics in momentum space.

Jan 1, 20090 citations

Macroscopic quantum tunneling with decoherence

Esteban Calzetta, Enric Verdaguer

The tunneling probability for a system modelling macroscopic quantum tunneling is computed. We consider an open quantum system with one degree of freedom consisting of a particle trapped in a cubic potential interacting with an environment characterized by a dissipative and a diffusion parameter. A representation based on the energy eigenfunctions of the isolated system, i. e. the system uncoupled to the environment, is used to write the dynamical master equation for the reduced Wigner function of the open quantum system. This equation becomes very simple in that representation. The use of the WKB approximation for the eigenfunctions suggests an approximation which allows an analytic computation of the tunneling rate, in this real time formalism, when the system is initially trapped in the false ground state. We find that the decoherence produced by the environment suppresses tunneling in agreement with results in other macroscopic quantum systems with different potentials. We confront our analytical predictions with an experiment where the escape rate from the zero voltage state was measured for a current-biased Josephson junction shunted with a resistor.

arXiv:quant-ph/0407185Jul 23, 20040 citations