Conductance fluctuations and weak localization in chaotic quantum dots

TL;DR

This paper investigates how temperature influences conductance fluctuations and weak localization in chaotic quantum dots, revealing the importance of energy correlations and highlighting issues in measuring dephasing rates.

Contribution

It introduces the significance of energy correlations in conductance variance calculations and identifies ambiguities in dephasing rate determination methods.

Findings

Energy correlations are crucial for accurate conductance fluctuation analysis.

Dephasing times at low temperatures are often underestimated.

The influence of thermal smearing on conductance fluctuations is characterized.

Abstract

We study the conductance statistical features of ballistic electrons flowing through a chaotic quantum dot. We show how the temperature affects the universal conductance fluctuations by analyzing the influence of dephasing and thermal smearing. This leads us to two main findings. First, we show that the energy correlations in the transmission, which were overlooked so far, are important for calculating the variance and higher moments of the conductance. Second, we show that there is an ambiguity in the method of determination of the dephasing rate from the size of the of the weak localization. We find that the dephasing times obtained at low temperatures from quantum dots are underestimated.