5 citations · 11 across the 3 of their papers we have counts for
5 papers · 1 filter
On the Matrix Representation of Quantum Operations
Yoshihiro Nambu, Kazuo Nakamura
This paper considers two frequently used matrix representations -- what we call the - and -matrices -- of a quantum operation and their applications. The matrices d…
Planar lightwave circuits for quantum cryptographic systems
Yoshihiro Nambu, Takaaki Hatanaka, Kazuo Nakamura
We propose a quantum cryptographic system based on a planar lightwave circuit (PLC) and report on optical interference experiments using PLC-based unbalanced Mach-Zehnder interfero…
Single-photon interference experiment over 100 km for quantum cryptography system using a balanced gated-mode photon detector
Hideo Kosaka, Akihisa Tomita, Yoshihiro Nambu +2
We demonstrate single-photon interference over 100 km using a balanced gated-mode photon detector and a plug & play system for quantum key distribution. The visibility with 0.1 pho…
Restoration of Entanglement by Spectral Filters
K. Usami, Y. Nambu, S. Ishizaka +4
We experimentally demonstrate that entanglement of bi-photon polarization state can be restored by spectral filters. This restoration procedure can be viewed as a new class of quan…
Information-Theoretic Description of No-go Theorem of a Bit Commitment
Yoshihiro Nambu, Yoshie Chiba-Kohno
We give a comprehensive and constructive proof of the no-go theorem of a bit commitment given by Mayers, Lo, and Chau from the viewpoint of quantum information theory. It is shown…