Single-electron Double Quantum Dot Dipole-coupled to a Single Photonic Mode

TL;DR

This paper demonstrates a hybrid quantum device where a single-electron double quantum dot is coupled to a microwave resonator, enabling precise measurement of tunnel coupling and decoherence properties through microwave spectroscopy.

Contribution

It introduces a novel hybrid system combining a double quantum dot with a superconducting resonator and models its behavior with a Jaynes-Cummings Hamiltonian, providing high-precision tunneling and decoherence measurements.

Findings

Microwave read-out yields precise tunnel coupling values.

Decoherence rates are similar in single-electron and many-electron regimes.

Dispersive and dissipative effects observed in the photonic mode.

Abstract

We have realized a hybrid solid-state quantum device in which a single-electron semiconductor double quantum dot is dipole coupled to a superconducting microwave frequency transmission line resonator. The dipolar interaction between the two entities manifests itself via dispersive and dissipative effects observed as frequency shifts and linewidth broadenings of the photonic mode respectively. A Jaynes-Cummings Hamiltonian master equation calculation is used to model the combined system response and allows for determining both the coherence properties of the double quantum dot and its interdot tunnel coupling with high accuracy. The value and uncertainty of the tunnel coupling extracted from the microwave read-out technique are compared to a standard quantum point contact charge detection analysis. The two techniques are found to be consistent with a superior precision for the microwave experiment when tunneling rates approach the resonator eigenfrequency. Decoherence properties of the double dot are further investigated as a function of the number of electrons inside the dots. They are found to be similar in the single-electron and many-electron regimes suggesting that the density of the confinement energy spectrum plays a minor role in the decoherence rate of the system under investigation.