Coherent time-dependent oscillations and temporal correlations in triangular triple quantum dots

TL;DR

This paper investigates time-dependent oscillations and correlations in triple quantum dots using waiting time distributions, revealing quantum coherence effects and tunable correlations that extend understanding beyond traditional current statistics.

Contribution

It introduces analysis of higher-order waiting time distributions in TQDs, demonstrating quantum coherence effects and correlations in multi-electron regimes with magnetic field control.

Findings

WTD exhibits coherent oscillations linked to dot occupation probabilities.

Quantum coherence induces correlations between successive waiting times.

Magnetic fields can tune dark states and correlations in TQDs.

Abstract

The fluctuation behavior of triple quantum dots (TQDs) has, so far, largely focused on current cumulants in the long-time limit via full counting statistics. Given that (TQDs) are non-trivial open quantum systems with many interesting features, such as Aharonov-Bohm interference and coherent population blocking, new fluctuating-time statistics, such as the waiting time distribution (WTD), may provide more information than just the current cumulants alone. In this paper, we use a Born-Markov master equation to calculate the standard and higher-order WTDs for coherentlycoupled TQDs arrayed in triangular ring geometries for several transport regimes. In all cases we find that the WTD displays coherent oscillations that correspond directly to individual time-dependent dot occupation probabilities, a result also reported recently in Ref.[1]. Our analysis, however, goes beyond the single-occupancy and single waiting time regimes, investigating waiting time behavior for TQDs occupied by multiple electrons and with finite electron-electron interactions. We demonstrate that, in these regimes of higher occupancy, quantum coherent effects introduce correlations between successive waiting times, which we can tune via an applied magnetic field. We also show that correlations can be used to distinguish between TQD configurations that have identical FCS and that dark states can be tuned with Aharonov-Bohm interference for more complicated regimes than single-occupancy.