Correlations in noisy Landau-Zener transitions

TL;DR

This paper analytically investigates how classical Gaussian noise affects Landau-Zener transitions in a two-level system, revealing the stochastic nature of transition probabilities and coherence, and deriving the magnetic response spectrum.

Contribution

It provides an analytic calculation of correlation functions and magnetic response in noisy Landau-Zener transitions, a novel approach in understanding noise effects.

Findings

Transition probabilities become random due to noise

Correlation functions of the system are derived analytically

Magnetic response spectrum and intensity are characterized

Abstract

We analyze the influence of classical Gaussian noise on Landau-Zener transitions during a two-level crossing in a time-dependent regular external field. Transition probabilities and coherence factors become random due to the noise. We calculate their two-time correlation functions, which describe the response of this two-level system to a weak external pulse signal. The spectrum and intensity of the magnetic response are derived. Although fluctuations are of the same order of magnitude as averages, the results is obtained in an analytic form.