Dissipative dynamics in a quantum bistable system: Crossover from weak to strong damping

Magazzù, Luca; Valenti, Davide; Spagnolo, Bernardo; Grifoni, Milena

doi:10.1103/physreve.92.032123

Cited by 21 publications

(27 citation statements)

References 69 publications

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“…In [46], by using a beyond-NIBA scheme we have investigated this crossover dynamical regime in the Ohmic case down to temperatures for which NIBA-like approximations break down.…”

Section: J Stat Mech (2016) 054016mentioning

confidence: 99%

“…Equation (17) does not capture transient oscillations and is accurate only in the fully incoherent regime. Nevertheless it gives a good estimate for the relaxation time also in the crossover dynamical regime [46]. The master equation (17) has been used to obtain the dynamics and stationary populations in the presence of an external driving [47] and to address the problem of the escape from a quantum metastable state, starting from a nonequilibrium initial condition, with a strongly asymmetric bistable potential and Ohmic dissipation [48].…”

Section: J Stat Mech (2016) 054016mentioning

confidence: 99%

“…If the temperature is low enough, the time evolution of a system prepared in one of these states does not display intrawell oscillations. These involve transitions to higher energy states induced by the heat bath, and a treatment based on the TLS approximation is appropriate (see [46] for a detailed exposition). However, at the temperatures considered in our work, especially at ω = T 0.5 0 , where ω 0 sets the order of magnitude of the separation between the first and second energy doublet, intrawell oscillations are expected to be activated regardless of the initial condition.…”

Section: J Stat Mech (2016) 054016mentioning

confidence: 99%

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Quantum dissipative dynamics of a bistable system in the sub-Ohmic to super-Ohmic regime

Magazzù¹,

Carollo²,

Spagnolo³

et al. 2016

J. Stat. Mech.

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Abstract. We investigate the quantum dynamics of a multilevel bistable system coupled to a bosonic heat bath beyond the perturbative regime. We consider dierent spectral densities of the bath, in the transition from subOhmic to super-Ohmic dissipation, and dierent cuto frequencies. The study is carried out by using the real-time path integral approach of the FeynmanVernon influence functional. We find that, in the crossover dynamical regime characterized by damped intrawell oscillations and incoherent tunneling, the short time behavior and the time scales of the relaxation starting from a nonequilibrium initial condition depend nontrivially on the spectral properties of the heat bath.

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“…In [46], by using a beyond-NIBA scheme we have investigated this crossover dynamical regime in the Ohmic case down to temperatures for which NIBA-like approximations break down.…”

Section: J Stat Mech (2016) 054016mentioning

confidence: 99%

Section: J Stat Mech (2016) 054016mentioning

confidence: 99%

Section: J Stat Mech (2016) 054016mentioning

confidence: 99%

See 1 more Smart Citation

Quantum dissipative dynamics of a bistable system in the sub-Ohmic to super-Ohmic regime

Magazzù¹,

Carollo²,

Spagnolo³

et al. 2016

J. Stat. Mech.

Self Cite

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“…At strong coupling this process is well approximated [171] by the incoherent relaxation captured by the master equation [172] …”

Section: Strong Dissipation: Analytical Approachmentioning

confidence: 99%

“…Note that spatial continuity is recovered for M → ∞, i.e., removing the upper bound on the energies taken into account. The existence of intermediate localized states in the generalization of the two-state system treatment accomplished by the DVR is reflected by the multiple time scales resulting from the inclusion of energy levels above the first doublet and accounts for tunneling and intra-well relaxation [87,171].…”

Section: Discrete Variable Representationmentioning

confidence: 99%

Nonlinear Relaxation Phenomena in Metastable Condensed Matter Systems

Spagnolo

Guarcello

Magazzù

et al. 2016

Entropy

Self Cite

100

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Nonlinear relaxation phenomena in three different systems of condensed matter are investigated. (i) First, the phase dynamics in Josephson junctions is analyzed. Specifically, a superconductor-graphene-superconductor (SGS) system exhibits quantum metastable states, and the average escape time from these metastable states in the presence of Gaussian and correlated fluctuations is calculated, accounting for variations in the the noise source intensity and the bias frequency. Moreover, the transient dynamics of a long-overlap Josephson junction (JJ) subject to thermal fluctuations and non-Gaussian noise sources is investigated. Noise induced phenomena are observed, such as the noise enhanced stability and the stochastic resonant activation. (ii) Second, the electron spin relaxation process in a n-type GaAs bulk driven by a fluctuating electric field is investigated. In particular, by using a Monte Carlo approach, we study the influence of a random telegraph noise on the spin polarized transport. Our findings show the possibility to raise the spin relaxation length by increasing the amplitude of the external fluctuations. Moreover, we find that, crucially, depending on the value of the external field strength, the electron spin depolarization length versus the noise correlation time increases up to a plateau. (iii) Finally, the stabilization of quantum metastable states by dissipation is presented. Normally, quantum fluctuations enhance the escape from metastable states in the presence of dissipation. We show that dissipation can enhance the stability of a quantum metastable system, consisting of a particle moving in a strongly asymmetric double well potential, interacting with a thermal bath. We find that the escape time from the metastable region has a nonmonotonic behavior versus the system-bath coupling and the temperature, producing a stabilizing effect.Keywords: metastability; nonequilibrium statistical mechanics and nonlinear relaxation time; noise enhanced stability; Josephson junction; spin polarized transport in semiconductors; open quantum systems; quantum noise enhanced stability

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Phase transition in quantum tunneling and exact statistical mechanics for a model of parameterized double‐well potential

Nzoupe

Dikandé

Tchawoua

2020

Math Methods in App Sciences

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A model for one-dimensional bistable systems characterized by a deformable double-well energy landscape is introduced in order to investigate the effect of shape deformability on the order of phase transition in quantum tunneling and on the quasi-exact integrability of the classical statistical mechanics of these systems. The deformable double-well energy landscape is modeled by a parameterized double-well potential possessing two fixed degenerate minima and a constant barrier height, but a tunable shape of its walls which affects the confinement of the two wells. It is found that unlike bistable models involving the standard 4 -field model for which the transition in quantum tunneling is predicted to be strictly of second order, a parameterization of the double-well potential also favors a first-order transition occurring above a universal critical value of the shape deformability parameter. The partition function of the model is constructed within the framework of the transfer integral formalism, with emphasis on low-lying eigenstates of the transfer integral operator. Criteria for quasi-exact integrability of the partition function were formulated, in terms of the condition for possible existence of exact eigenstates of the transfer integral operator. The quasi-exact solvability condition is obtained analytically, and from this, some exact eigenstates are derived at several temperatures. The exact probability densities obtained from the analytical expressions of the ground state wavefunctions at different temperatures are found to be in excellent agreement with the probability density obtained from numerical simulations of the Fokker-Planck equation.

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Dissipative dynamics in a quantum bistable system: Crossover from weak to strong damping

Cited by 21 publications

References 69 publications

Quantum dissipative dynamics of a bistable system in the sub-Ohmic to super-Ohmic regime

Quantum dissipative dynamics of a bistable system in the sub-Ohmic to super-Ohmic regime

Nonlinear Relaxation Phenomena in Metastable Condensed Matter Systems

Phase transition in quantum tunneling and exact statistical mechanics for a model of parameterized double‐well potential

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