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Using Spontaneous Emission of a Qubit as a Resource for Feedback Control
P Campagne-Ibarcq1,2, S Jezouin1,2, N Cottet1,2
1Laboratoire Pierre Aigrain, Ecole Normale Supérieure-PSL Research University, CNRS, Université Pierre et Marie Curie-Sorbonne Universités, Université Paris Diderot-Sorbonne Paris Cité, 24 rue Lhomond, 75231 Paris Cedex 05, France.
Physical Review Letters
|August 20, 2016
Summary
Researchers demonstrate persistent control of transmon qubits using continuous measurement feedback. This quantum feedback protocol enables stable qubit states, advancing quantum computing control methods.
Area of Science:
- Quantum computing
- Quantum information science
- Solid-state physics
Background:
- Transmon qubits are a leading platform for quantum computation.
- Maintaining qubit coherence and control is crucial for scalable quantum computers.
- Feedback protocols are essential for real-time quantum system management.
Purpose of the Study:
- To implement a persistent feedback control protocol for transmon qubits.
- To stabilize a transmon qubit in any arbitrary target state.
- To demonstrate analog Markovian feedback in the quantum regime.
Main Methods:
- Continuous heterodyne measurement of transmon qubit fluorescence.
- Microwave driving of the qubit and cavity with feedback-controlled amplitudes.
- Utilizing a Josephson mixer as a phase-preserving amplifier.
- Achieving a total measurement efficiency of 35%.
Main Results:
- Permanent stabilization of the transmon qubit in targeted states was achieved.
- Maximum excitation of 59% and coherence of 44% for stabilized states.
- Demonstration of multiple-input multiple-output analog Markovian feedback.
Conclusions:
- The developed feedback protocol enables robust and persistent control of transmon qubits.
- This work showcases the potential of continuous measurement and feedback for quantum state stabilization.
- The findings contribute to the advancement of quantum control techniques for quantum information processing.
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