Microwave-Driven Transitions in Two Coupled Semiconductor Charge Qubits

TL;DR

This study investigates microwave-induced transitions in two capacitively coupled semiconductor charge qubits, demonstrating resonant control and measurement of their interaction dynamics in a double quantum dot system.

Contribution

It provides experimental evidence of coupled two-qubit interactions in semiconductor quantum dots using microwave driving and charge detection techniques.

Findings

Observation of resonant transitions consistent with a coupled two-qubit Hamiltonian

Demonstration of microwave-driven control of charge qubits

Probing of two-qubit level structure through detuning variation

Abstract

We have studied interactions between two capacitively coupled GaAs/AlGaAs few-electron double quantum dots. Each double quantum dot defines a tunable two-level system, or qubit, in which a single excess electron occupies either the ground state of one dot or the other. Applying microwave radiation we resonantly drive transitions between states and non-invasively measure occupancy changes using proximal quantum point contact charge detectors. The level structure of the interacting two-qubit system is probed by driving it at a fixed microwave frequency whilst varying the energy detuning of both double dots. We observe additional resonant transitions consistent with a simple coupled two-qubit Hamiltonian model.