Dissipative tunneling by means of scaled trajectories

TL;DR

This paper compares dissipative quantum tunneling using scaled trajectories in Kostin and Caldirola-Kanai models, revealing higher transmission probabilities in the nonlinear Kostin approach due to environmental effects.

Contribution

It introduces a scaled nonlinear Kostin equation for dissipative tunneling and compares it with the linear Caldirola-Kanai model, highlighting the impact of environment-induced decoherence.

Findings

Kostin approach yields higher transmission probabilities than Caldirola-Kanai.

Scaled trajectories show gradual decoherence in open quantum systems.

Environmental effects are better captured by nonlinear quantum equations.

Abstract

Dissipative quantum tunnelling through an inverted parabolic barrier is considered in the presence of an electric field. A Schr\"odinger-Langevin or Kostin quantum classical transition wave equation is used and applied resulting in a scaled differential equation of motion. A Gaussian wave packet solution to the resulting scaled Kostin nonlinear equation is assumed and compared to the same solution for the scaled linear Caldirola-Kanai equation. The resulting scaled trajectories are obtained at different dynamical regimes and friction cases, showing the gradual decoherence process in this open dynamics. Theoretical results show that the transmission probabilities are always higher in the Kostin approach than in the Caldirola-Kanai approach in the presence or not of an external electric field. This discrepancy should be understood due to the presence of an environment since the corresponding open dynamics should be governed by nonlinear quantum equations, whereas the second approach is issued from an effective Hamiltonian within a linear theory.