Numerical simulations of quantum clock for measuring tunneling times

TL;DR

This paper numerically investigates two quantum clock methods for measuring tunneling times, revealing that tunneling times can appear shorter for higher barriers and highlighting the influence of spin-flip probabilities and filtering effects.

Contribution

It compares the Larmor clock and spin-flip methods for tunneling time measurement, providing new insights into their behaviors at higher barriers.

Findings

Larmor tunneling time can be shorter for higher barriers

Spin-flip probability increases with barrier height

Filtering effects influence apparent tunneling times

Abstract

We numerically study two methods of measuring tunneling times using a quantum clock. In the conventional method using the Larmor clock, we show that the Larmor tunneling time can be shorter for higher tunneling barriers. In the second method, we study the probability of a spin-flip of a particle when it is transmitted through a potential barrier including a spatially rotating field interacting with its spin. According to the adiabatic theorem, the probability depends on the velocity of the particle inside the barrier. It is numerically observed that the probability increases for higher barriers, which is consistent with the result obtained by the Larmor clock. By comparing outcomes for different initial spin states, we suggest that one of the main causes of the apparent decrease in the tunneling time can be the filtering effect occurring at the end of the barrier.