2022/12/21 by Go Kato, Kato, Go, Kiyoshi Tamaki +5
Computer Science · Engineering · Physics and Astronomy · #FOS: Physical sciences #Mechanical and Optical Resonators #Optics (physics.optics) #Photonic and Optical Devices #Quantum Information and Cryptography #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2212.10958
openalex publication_date 2022/12/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The homodyne detection is one of the most basic tools for identifying the quantum state of light. It has been used to detect useful non-local properties, such as entanglement for the quantum teleportation and distillability of a secret key in quantum key distribution. In so doing, the detection scheme employs a bright optical pulse, called the local oscillator (LO) pulse, and the LO pulse is usually transmitted along with the signal pulses. The LO pulse is presumed to be a coherent state with an infinite intensity. However, it is difficult in practice to hold this presumption owing to noise in the optical transmission channels or an intervention by a malicious third party. As a result, the implementation may no longer be the homodyne detection, and those outcomes may merely disguise successful detection of entanglement or a secret key. Here, we present an alternative scheme that works as the homodyne detection to detect the non-local properties of light in a verifiable manner, without any presumption for the LO pulses. This scheme is essentially based on the same setup as the conventional implementation for the homodyne detection. This result contributes to close any possible loophole in the homodyne detection caused by the deviation from the ideal LO pulses.