Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics G Nuclear and Particle Physics

Analytical model for quantum tunnelling with dissipation through a fission-like barrier

Eliade N. Stefanescu, A. Sãndulescu, Walter Greiner

Published May 1, 1994• 11 citations
Publisher

Abstract

Analytical expressions for the spectral density of the tunnelling rate are found for a fission-like analytical barrier, having three parts: an internal part approximated by a harmonic oscillator, a top part considered constant and an external part considered as a Coulomb potential. We found that environment-assisted tunnelling processes are present for all three regions and that an environment-stimulated decay is significant only for the Coulomb part of the barrier. Numerical calculations are made for the cold fission of 236 U to 138 Xe+ 98 Sr.

DOI
10.1088/0954-3899/20/5/014

Related papers

Quantum dissipation in cluster decay phenomena: I. Smoothly joined quadratic potentials

Şerban Mişicu

This paper is devoted to the study of quantum dissipation in nuclear cluster decay phenomena within the framework of the Lindblad approach to quantum open systems. Typical examples of nuclear decay phenomena, such as cluster radioacivity, spontaneous cold fission of actinide nuclei or quasi-fission of super-heavy nuclei can be described by considering the tunnelling of a metastable state across a piecewise quadratic potential. Two study cases are considered: (i) a harmonic well smoothly joined to an inverted parabola which simulates the barrier and (ii) the inverted parabola of case (i) is continued with a second harmonic well. The width and depth of the second harmonic oscillator well are varied over a wide range of values in order to encompass particular cases of tunnelling in the double-well potential. The evolution of the averages and covariances of the quantum sub-system is studied in both under- and over-damped regimes. For a Gaussian initial wavepacket we compute the tunnelling probability for different values of the friction coefficient and fixed values of the diffusion coefficients. The ansatz used for these coefficients corresponds to the case with temperature T = 0.

Journal of Physics G Nuclear and Particle Physics•Aug 25, 2000•1 citation

QUANTUM BROWNIAN MOTION AND NUCLEAR FISSION

Yuanshun Huo

Based on a simplified Hamiltonian model the transition from quantum to classical diffu- sion behaviours for a system has been shown.The approximation of a locally harmonic oscilla- tor and reduced density operator propagator in the harmonic oscillator are generalized to cal- culate the escape rate over the barrier for the system in a fission potential consisting of a gro- und state well and barrier.

Chinese Physics C•Jan 1, 1990•0 citations

Quantum Brownian motion and nuclear fission

Xi-Zhen Wu, Zhuxia Li, Joachim Alexander Maruhn +2 more

Based on a simplified Hamiltonian model the transition from quantum to classical diffusion behaviours for a system has been shown by studying the dependence of the quantum Brownian motion in a harmonic oscillator potential on the viscosity and temperature of the system. The approximation of a locally harmonic oscillator and reduced density operator propagator in the harmonic oscillator are generalised to calculate the escape rate over the barrier for the system in a fission potential consisting of a ground-state well and barrier. Compared with the results of the Fokker-Planck equation the model in this paper is completely quantum mechanical.

Journal of Physics G Nuclear Physics•Aug 1, 1988•4 citations

Quantum tunneling in dissipative systems

Edward G. Harris

As a prelude to a discussion of tunneling in the presence of dissipation, we discuss the damped harmonic oscillator. We show that for a harmonic-oscillator potential, the Caldeira-Leggett Hamiltonian can be reduced to a sum of independent harmonic-oscillator Hamiltonians by a normal-mode transformation. We then discuss tunneling through a parabolic barrier and explain the apparently contradictory results in the literature. The decay of a metastable state is then discussed. We argue that much of the published work on tunneling in dissipative systems has assumed unphysical initial conditions. We calculate the tunneling out of a metastable state, on the assumption that the environment is initially at zero temperature, and find that quantum tunneling is enhanced by dissipation.

Physical Review A•Aug 1, 1993•33 citations

Fission rate and transient time with a quantum master equation

Vazgen Valerikovich Sargsyan, Yu. V. Palchikov, Z. Kanokov +2 more

The induced nuclear fission is considered a transport process over the fission barrier underlying dissipative forces. Using a quantum master equation for the reduced density matrix, the influence of microscopical diffusion coefficients on the total fission time and transient time is studied. The influence of transient effects on the probability of the first-chance fission is estimated. For different temperatures and friction coefficients, the quasistationary fission rate is compared with the analytical Kramers formula.

Physical Review C•Dec 10, 2007•26 citations

Quantum tunneling through a dissipative barrier

Eliade N. Stefanescu, A. Sãndulescu, Paul E. Sterian

For a tunneling system we consider the coupling to the dissipative environment of the coordinate q, the momentum p and the potential function U(q). In the frame of the quantum theory of open systems we derive a quantum master equation, fundamental constraints and uncertainty relations. We obtain an analytical expression of the tunneling spectrum and show that at thermal equilibrium its shape entirely depends on the barrier characteristics while its amplitude is proportional to the strength of the dissipative coupling.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Mar 8, 1995•2 citations
Analytical expressions for the spectral density of the tunnelling rate are found for a fission-like analytical barrier, having three parts: an internal part approximated by a harmonic oscillator, a top part considered constant and an external part considered as a Coulomb potential. We found that environment-assisted tunnelling processes are present for all three regions and that an environment-stimulated decay is significant only for the Coulomb part of the barrier. Numerical calculations are made for the cold fission of 236 U to 138 Xe+ 98 Sr.
This paper is devoted to the study of quantum dissipation in nuclear cluster decay phenomena within the framework of the Lindblad approach to quantum open systems. Typical examples of nuclear decay phenomena, such as cluster radioacivity, spontaneous cold fission of actinide nuclei or quasi-fission of super-heavy nuclei can be described by considering the tunnelling of a metastable state across a piecewise quadratic potential. Two study cases are considered: (i) a harmonic well smoothly joined to an inverted parabola which simulates the barrier and (ii) the inverted parabola of case (i) is continued with a second harmonic well. The width and depth of the second harmonic oscillator well are varied over a wide range of values in order to encompass particular cases of tunnelling in the double-well potential. The evolution of the averages and covariances of the quantum sub-system is studied in both under- and over-damped regimes. For a Gaussian initial wavepacket we compute the tunnelling probability for different values of the friction coefficient and fixed values of the diffusion coefficients. The ansatz used for these coefficients corresponds to the case with temperature T = 0.
Based on a simplified Hamiltonian model the transition from quantum to classical diffusion behaviours for a system has been shown by studying the dependence of the quantum Brownian motion in a harmonic oscillator potential on the viscosity and temperature of the system. The approximation of a locally harmonic oscillator and reduced density operator propagator in the harmonic oscillator are generalised to calculate the escape rate over the barrier for the system in a fission potential consisting of a ground-state well and barrier. Compared with the results of the Fokker-Planck equation the model in this paper is completely quantum mechanical.
As a prelude to a discussion of tunneling in the presence of dissipation, we discuss the damped harmonic oscillator. We show that for a harmonic-oscillator potential, the Caldeira-Leggett Hamiltonian can be reduced to a sum of independent harmonic-oscillator Hamiltonians by a normal-mode transformation. We then discuss tunneling through a parabolic barrier and explain the apparently contradictory results in the literature. The decay of a metastable state is then discussed. We argue that much of the published work on tunneling in dissipative systems has assumed unphysical initial conditions. We calculate the tunneling out of a metastable state, on the assumption that the environment is initially at zero temperature, and find that quantum tunneling is enhanced by dissipation.
The induced nuclear fission is considered a transport process over the fission barrier underlying dissipative forces. Using a quantum master equation for the reduced density matrix, the influence of microscopical diffusion coefficients on the total fission time and transient time is studied. The influence of transient effects on the probability of the first-chance fission is estimated. For different temperatures and friction coefficients, the quasistationary fission rate is compared with the analytical Kramers formula.
For a tunneling system we consider the coupling to the dissipative environment of the coordinate q, the momentum p and the potential function U(q). In the frame of the quantum theory of open systems we derive a quantum master equation, fundamental constraints and uncertainty relations. We obtain an analytical expression of the tunneling spectrum and show that at thermal equilibrium its shape entirely depends on the barrier characteristics while its amplitude is proportional to the strength of the dissipative coupling.