Multiphoton Processes in Driven Mesoscopic Systems

TL;DR

This paper investigates multi-photon absorption and emission in mesoscopic rings under time-dependent flux, revealing a connection to random walk models and analyzing the transition between quantum and classical regimes.

Contribution

It introduces an analogy between quantum kinetic equations and random walk models to study multiphoton processes in driven mesoscopic systems, highlighting the crossover regimes.

Findings

Identifies the analogy between Keldysh equations and random walks in energy space.

Analyzes the probability distribution of multi-photon absorption/emission.

Explores the transition from quantum to classical behavior in driven mesoscopic systems.

Abstract

We study the statistics of multi-photon absorption/emission processes in a mesoscopic ring threaded by an harmonic time-dependent flux $\Phi(t)$. For this sake, we demonstrate a useful analogy between the Keldysh quantum kinetic equation for the electrons distribution function and a Continuous Time Random Walk in energy space with corrections due to interference effects. Studying the probability to absorb/emit $n$ quanta $\hbar\omega$ per scattering event, we explore the crossover between ultra-quantum/low-intensity limit and quasi-classical/high-intensity regime, and the role of multiphoton processes in driving it.