Controlled-Phase Gate Using Dynamically Coupled Cavities and Optical Nonlinearities.

Area of Science:

• Quantum Information Science
• Integrated Photonics
• Quantum Optics

Background:

• Implementing high-fidelity quantum gates is crucial for quantum computing.
• Optical nonlinearities offer a pathway for quantum gate operations.
• Wave packet distortions limit fidelity in some nonlinear optical processes.

Purpose of the Study:

• To propose and analyze a novel integrated photonic circuit architecture for a high-fidelity deterministic controlled-phase gate.
• To investigate the use of bulk optical nonlinearities for quantum gate implementation.
• To reduce wave packet distortions associated with optical nonlinearities.

Main Methods:

• Utilizing integrated photonic circuits with dynamically controlled cavity-waveguide coupling.
• Converting traveling photonic qubits into stationary cavity modes using classical control fields.
• Employing self-phase modulation in chi^{(3)} materials and second-harmonic generation in chi^{(2)} materials.

Main Results:

• Achieved high-fidelity deterministic controlled-phase gates between photonic qubits.
• Demonstrated reduction of wave packet distortions using the proposed architecture.
• Showed that gate fidelity approaches unity with increased photon storage time.
• Identified a trade-off between loss and wave packet distortion errors using dynamically coupled cavities.

Conclusions:

• The proposed integrated photonic circuit architecture offers a practical route to high-fidelity quantum gates.
• The approach is compatible with room-temperature operation and uses demonstrated components.
• This work advances the development of scalable quantum computing hardware.