Faithful Quantum Teleportation via a Nanophotonic Nonlinear Bell State Analyzer

Area of Science:

• Quantum Information Science
• Nanophotonics
• Quantum Communication

Background:

• Quantum networking relies on linear-optical Bell state measurements for information transfer.
• Linear optics face limitations due to photon indistinguishability requirements and multiphoton emission errors, hindering quantum protocol efficiency and fidelity.

Purpose of the Study:

• To develop a novel nonlinear Bell state analyzer for time-bin encoded photons.
• To overcome the limitations of linear-optical Bell state measurements in quantum networking protocols.
• To demonstrate faithful quantum teleportation with spectrally distinct photons.

Main Methods:

• Utilized a nanophotonic cavity with sum-frequency generation for nonlinear Bell state analysis.
• Engineered the system to filter multiphoton emissions, achieving a sum-frequency generation efficiency of 4×10⁻⁵.
• Implemented the nonlinear analyzer for quantum teleportation experiments with time-bin encoded photons.

Main Results:

• Achieved faithful quantum teleportation of spectrally distinct photons with fidelities ≥94% at the single-photon level.
• Demonstrated effective filtering of multiphoton emissions, a key error source in linear optics.
• Showcased nonlinear-optical entangling operations on a nanophotonics platform.

Conclusions:

• The nonlinear Bell state analyzer enables practical quantum networks by eliminating the need for identical photons.
• This approach bypasses the fundamental fidelity limitations inherent in linear-optical Bell state measurements.
• Advances in nanophotonics empower efficient nonlinear operations for robust quantum information protocols.