3 papers
math.RT2026
Estimating the spectral radius of Bell-type operator via finite dimensional approximation of orthogonal projections
Yuki Fujii, Toyohiro Tsurumaru
We establish a new decomposition formula for two orthogonal projections P and Q on a separable Hilbert space V. This formula yields an orthogonal direct sum decomposition of V into…
quant-ph2025
Security loophole in error verification in quantum key distribution
Toyohiro Tsurumaru, Akihiro Mizutani, Toshihiko Sasaki
The security of quantum key distribution (QKD) is evaluated based on the secrecy of Alice's key and the correctness of the keys held by Alice and Bob. A practical method for ensuri…
quant-ph2024
Tight scaling of key rate for differential-phase-shift quantum key distribution
Akihiro Mizutani, Toyohiro Tsurumaru
The performance of quantum key distribution (QKD) protocols is evaluated based on the ease of implementation and key generation rate. Among major protocols, the differential-phase-…