Efficiency of Mesoscopic Detectors

TL;DR

This paper analyzes the efficiency of mesoscopic detectors in measuring two-level systems, deriving conditions for optimal measurement and illustrating with chaotic cavity ensembles.

Contribution

It introduces a scattering matrix approach to evaluate relaxation, decoherence, and measurement times, providing new criteria for detector efficiency in mesoscopic systems.

Findings

Derived conditions for efficient measurement ratio

Calculated relaxation and decoherence times

Analyzed efficiency distribution in chaotic cavities

Abstract

We consider a mesoscopic measuring device whose conductance is sensitive to the state of a two-level system. The detector is described with the help of its scattering matrix. Its elements can be used to calculate the relaxation and decoherence time of the system, and determine the characteristic time for a reliable measurement. We derive conditions needed for an efficient ratio of decoherence and measurement time. To illustrate the theory we discuss the distribution function of the efficiency of an ensemble of open chaotic cavities.