A quantum phase gate capable of effectively collecting photons based on a gap plasmon structure

Area of Science:

• Quantum physics
• Nanotechnology
• Optics

Background:

• Miniaturization and integration of on-chip quantum circuits are crucial for advancing quantum technologies.
• Surface plasmons offer ultra-small mode volumes for reducing quantum device size.
• High-fidelity quantum phase gates in surface plasmon nanocavities remain a challenge.

Purpose of the Study:

• To theoretically demonstrate a high-fidelity quantum phase gate using a metallic nanocone-nanowire structure.
• To achieve arbitrary phase shift and effective nanoscale photon collection simultaneously.
• To explore the potential of this system as universal quantum nodes.

Main Methods:

• Utilizing a metallic nanocone-nanowire structure to support surface plasmons.
• Leveraging gap plasmons for enhanced coupling coefficients.
• Incorporating a gain medium to reduce cavity loss.

Main Results:

• Demonstrated a quantum phase gate with 88.8% fidelity.
• Achieved simultaneous arbitrary phase shift and nanoscale photon collection.
• Reported photon collection efficiency over 30% via the nanowire.

Conclusions:

• The proposed system offers a viable route for on-chip quantum gate realization.
• The nanocone-nanowire structure can function as universal quantum nodes for processing and storing quantum information.
• This work holds promise for developing multifunctional quantum gates and novel quantum circuits.