Nonuniversal dynamic conductance fluctuations in disordered systems

TL;DR

This paper investigates the nonuniversal nature of dynamic conductance fluctuations in disordered systems, revealing their dependence on sample parameters and their growth over time, contrasting with steady-state universal conductance fluctuations.

Contribution

It demonstrates that time-dependent conductance fluctuations are nonuniversal and depend on sample parameters, providing a theoretical and experimental analysis of their temporal behavior.

Findings

Variance of conductance increases as t^3 after excitation.

Dynamic conductance fluctuations depend on sample parameters.

C_3(t) surpasses C_2(t) after a characteristic time t_q.

Abstract

Sample-to-sample fluctuations of the time-dependent conductance of a system with static disorder have been studied by means of diagrammatic theory and microwave pulsed transmission measurements. The fluctuations of time-dependent conductance are not universal, i.e., depend on sample parameters, in contrast to the universal conductance fluctuations in the steady-state regime. The variance of normalized conductance, determined by the infinite-range intensity correlation C_3(t), is found to increase as a third power of delay time from an exciting pulse, t. C_3(t) grows larger than the long-range intensity correlation C_2(t) after a time t_q ~ <g>^{1/2} t_D (t_D being the diffusion time, <g> being the average dimensionless conductance).