Construction of controlled-NOT gate based on microwave-activated phase (MAP) gate in two transmon system

Area of Science:

• Quantum computing
• Superconducting circuits
• Quantum information science

Background:

• Controlled-NOT (cNOT) gates are fundamental building blocks for quantum computation.
• Superconducting transmon qubits are a leading platform for realizing quantum gates.
• Previous cNOT gate implementations faced challenges in fidelity and scalability.

Purpose of the Study:

• To experimentally construct an all-microwave scheme for a high-fidelity cNOT gate between two superconducting transmon qubits.
• To demonstrate the efficacy of the microwave-activated phase (MAP) gate with phase compensation for cNOT gate implementation.
• To showcase the practical application of the developed cNOT gate in executing the Deutsch-Jozsa algorithm.

Main Methods:

• Utilized a three-dimensional cavity to couple two superconducting transmon qubits.
• Implemented a microwave-activated phase (MAP) gate, requiring additional phase compensation steps.
• Employed Z-axis phase gates with precisely calibrated microwave hyperbolic secant pulses.
• Evaluated gate performance using two-qubit quantum process tomography (QPT).

Main Results:

• Successfully constructed and characterized an all-microwave cNOT gate between transmon qubits.
• Demonstrated the effectiveness of the MAP gate combined with phase compensation techniques.
• Achieved a high-fidelity quantum gate operation, validated by QPT.

Conclusions:

• The developed all-microwave scheme provides a robust method for implementing cNOT gates in superconducting quantum processors.
• The successful demonstration of the Deutsch-Jozsa algorithm highlights the potential of this cNOT gate for practical quantum computation.
• This work contributes to the advancement of scalable and high-fidelity quantum computing architectures.