Microwave-resonator-detected excited-state spectroscopy of a double quantum dot

TL;DR

This paper demonstrates high-sensitivity excited-state spectroscopy of a GaAs double quantum dot using a superconducting NbTiN resonator, revealing spin-state transitions and the effect of tunneling rates, advancing quantum dot readout techniques.

Contribution

It introduces a method using a high-impedance NbTiN resonator for detailed spectroscopy of quantum dot energy states and spin transitions.

Findings

Distinct spin-state transitions identified via resonator response

Interdot tunneling rate influences the resonator signal

Experimental results match theoretical simulations

Abstract

As an application in circuit quantum electrodynamics (cQED) coupled systems, superconducting resonators play an important role in high-sensitivity measurements in a superconductingsemiconductor hybrid architecture. Taking advantage of a high-impedance NbTiN resonator, we perform excited-state spectroscopy on a GaAs double quantum dot (DQD) by applying voltage pulses to one gate electrode. The pulse train modulates the DQD energy detuning and gives rise to charge state transitions at zero detuning. Benefiting from the outstanding sensitivity of the resonator, we distinguish different spin-state transitions in the energy spectrum according to the Pauli exclusion principle. Furthermore, we experimentally study how the interdot tunneling rate modifies the resonator response. The experimental results are consistent with the simulated spectra based on our model.