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Real-time two-axis control of a spin qubit
Fabrizio Berritta1, Torbjørn Rasmussen2, Jan A Krzywda3
1Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark. fabrizio.berritta@nbi.ku.dk.
Nature Communications
|February 23, 2024
Summary
This study introduces a real-time quantum control protocol for qubits, using dynamic waveform generation to stabilize performance against environmental noise. The method optimizes qubit operations by estimating and correcting Hamiltonian parameter fluctuations in real time.
Area of Science:
- Quantum Computing
- Quantum Control
- Solid-State Physics
Background:
- Qubit control is challenged by environmental noise affecting Hamiltonian parameters.
- Adapting to these dynamic changes is crucial for stable quantum computations.
Purpose of the Study:
- To demonstrate a real-time control protocol for a two-electron singlet-triplet qubit.
- To dynamically stabilize and optimize qubit performance against fluctuating Hamiltonian parameters.
Main Methods:
- Leveraging single-shot readout classification and dynamic waveform generation.
- Utilizing field-programmable gate array (FPGA) for real-time Hamiltonian estimation.
- Estimating Overhauser field gradient and exchange interaction for dynamic correction.
Main Results:
- Achieved real-time estimation and correction of fluctuating qubit parameters.
- Enabled controlled Overhauser-driven spin rotations without external magnets.
- Extended coherence of Hadamard rotations by correcting for qubit axis fluctuations.
Conclusions:
- Feedback-based control is essential for enhancing quantum device performance and stability.
- The demonstrated protocol effectively mitigates quasistatic noise in qubits.
- This approach offers a pathway to more robust quantum information processing.
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