Fast and Unconditional All-Microwave Reset of a Superconducting Qubit

Area of Science:

• Quantum Computing
• Quantum Information Science

Background:

• Active qubit reset is essential for quantum algorithms and error correction.
• Superconducting qubits, like transmons, require reliable reset protocols for high-fidelity operations.

Purpose of the Study:

• To experimentally demonstrate a novel reset scheme for a three-level transmon artificial atom.
• To achieve fast and efficient reinitialization of the transmon-resonator system to its ground state.

Main Methods:

• Utilized a microwave-induced interaction between specific transmon-resonator states (|f,0⟩ and |g,1⟩).
• Characterized the reset process in a coupled transmon-resonator system.

Main Results:

• Achieved qubit reinitialization to the ground state in under 500 nanoseconds.
• Demonstrated a residual excitation of only 0.2% after the reset protocol.

Conclusions:

• The demonstrated reset protocol is practical, requiring no additional architecture beyond single-shot readout.
• The protocol operates without the need for feedback mechanisms, simplifying implementation.