Quantum Stochastic Absorption

TL;DR

This paper investigates wave propagation in a one-dimensional disordered medium with stochastic absorption, revealing how absorption affects localization, reflection, and transmission, and contrasting it with coherent absorption.

Contribution

It provides a systematic analysis of stochastic absorption effects on wave localization and reflection, introducing a new model and comparing it with coherent absorption.

Findings

Localization length is modified by absorption as a0_w _eta / (_w + _eta)

Reflection decreases monotonically with increasing absorption 

Stationary reflection distribution matches random phase approximation predictions

Abstract

We report a detailed and systematic study of wave propagation through a stochastic absorbing random medium. Stochastic absorption is modeled by introducing an attenuation constant per unit length $\alpha$ in the free propagation region of the one-dimensional disordered chain of delta function scatterers. The average value of the logarithm of transmission coefficient decreases linearly with the length of the sample. The localization length is given by $\xi ~ = ~ \xi_w \xi_\alpha / (\xi_w + \xi_\alpha)$, where $\xi_w$ and $\xi_\alpha$ are the localization lengths in the presence of only disorder and of only absorption respectively. Absorption does not introduce any additional reflection in the limit of large $\alpha$, i.e., reflection shows a monotonic decrease with $\alpha$ and tends to zero in the limit of $\alpha\to\infty$, in contrast to the behavior observed in case of coherent absorption. The stationary distribution of reflection coefficient agrees well with the analytical results obtained within random phase approximation (RPA) in a larger parameter space. We also emphasize the major differences between the results of stochastic and coherent absorption.