Noise spectroscopy using correlations of single-shot qubit readout

Area of Science:

• Quantum Computing
• Quantum Information Science
• Condensed Matter Physics

Background:

• Understanding noise is critical for enhancing qubit performance and reducing decoherence.
• Traditional methods for noise spectrum extraction require precise qubit control and long relaxation times, limiting their applicability.

Purpose of the Study:

• To present an alternative, more accessible method for extracting the noise spectrum affecting qubits.
• To enable noise spectrum analysis even when accurate qubit control and long relaxation times are unavailable.

Main Methods:

• The study utilizes correlations of single-shot measurement outcomes from successive free induction decays.
• This novel approach requires only moderate fidelity qubit initialization and readout.
• It allows independent tuning of sensitivity and the frequency range of detection.

Main Results:

• The proposed method successfully extracts the noise spectrum from qubit measurements.
• It demonstrates the ability to maintain good detection contrast across a wide frequency range.
• The technique is shown to be effective for measuring 1/f noise and nuclear bath fluctuations in GaAs spin qubits.

Conclusions:

• This new method provides a practical alternative for characterizing qubit noise spectra.
• Its reduced requirements for qubit control and relaxation times broaden its utility in quantum computing research.
• The technique offers enhanced flexibility for probing noise across diverse frequency regimes.