Integrated photonic source of Gottesman-Kitaev-Preskill qubits

Area of Science:

• Quantum Information Science
• Integrated Photonics
• Quantum Computing

Background:

• Photonic quantum computers require robust optical states for qubit encoding.
• Gottesman-Kitaev-Preskill (GKP) states offer a promising approach for universal gate sets using Gaussian operations.
• Previous GKP state generation relied on free-space optics, limiting scalability.

Purpose of the Study:

• To demonstrate the generation of GKP qubit states using an integrated photonic chip.
• To assess the suitability of these integrated GKP states for fault-tolerant quantum computing.

Main Methods:

• Fabrication of an ultra-low-loss integrated photonic chip on a silicon nitride platform.
• Coupling the chip with high-efficiency photon number resolving detectors.
• Characterization of generated GKP states, including quadrature distributions and Wigner function negativity.

Main Results:

• Successful generation of GKP qubit states on an integrated photonic chip.
• Observed critical mode-level features for fault tolerance, including multiple quadrature peaks and a 3x3 lattice structure in the Wigner function.
• Demonstrated potential for fault-tolerant GKP states with further loss reduction.

Conclusions:

• The integrated photonic chip approach validates a key component for bosonic quantum computing architectures.
• This work paves the way for scalable GKP state sources for future fault-tolerant quantum computers.
• The developed technology supports the advancement of room-temperature compatible photonic quantum computing.