Suppressing qubit dephasing using real-time Hamiltonian estimation

Area of Science:

• Quantum Information Science
• Quantum Computing
• Materials Science

Background:

• Quantum systems interact with fluctuating environments, causing decoherence.
• Decoherence is a major barrier to scalable quantum information processing.
• Existing mitigation strategies increase experimental complexity.

Purpose of the Study:

• To improve qubit coherence by mitigating environmental decoherence.
• To develop a real-time Hamiltonian parameter estimation technique for qubits.
• To enhance the performance of quantum information processing applications.

Main Methods:

• Utilized a rapidly converging Bayesian approach for Hamiltonian parameter estimation.
• Precisely measured singlet-triplet spin qubit splitting faster than environmental fluctuations.
• Continuously adjusted qubit control parameters based on real-time measurements.

Main Results:

• Improved inhomogenously broadened coherence time (T2*) from tens of nanoseconds to over 2 microseconds.
• Demonstrated a technique compatible with arbitrary qubit operations.
• Successfully mitigated decoherence in a qubit system.

Conclusions:

• Real-time Hamiltonian parameter estimation significantly enhances qubit coherence.
• This technique complements quantum error correction and benefits quantum information processing.
• The method has potential applications in meteorological and quantum computing fields.