Fumihiro Kaneda, So-Young Baek, Masanao Ozawa, and Keiichi Edamatsu
Physical Review Letters 112(2) 020402/1-020402/5 Jan 2014 [Refereed]
We experimentally test the error-disturbance uncertainty relation (EDR) in generalized, strength-variable
measurement of a single photon polarization qubit, making use of weak measurement that keeps the initial
signal state practically unchanged.W...
Physical Review A 78 032106 (1-7) Sep 2008 [Refereed]
The Wigner-Araki-Yanase (WAY) theorem shows that additive conservation laws limit the accuracy of measurements. Recently, various quantitative expressions have been found for quantum limits on measurements induced by additive conservation laws, an...
Quantum precision limits for any implementation of single qubit gates under conservation laws
T. Karasawa, M. Ozawa, J. Gea-Banacloche, and K. Nemoto
International Journal of Quantum Information 6 701-706 Jul 2008 [Refereed]
Low-noise channel estimation
M. Hotta, T. Karasawa, K. Matsumoto, and M. Ozawa
Proc. 8th Int. Conf. on Quantum Communication, Measurement and Computing (NICT Press, Tokyo) 319-322 Jul 2007 [Refereed]
Simultaneous measurability of non-commuting observables and the universal uncertainty principle
Proc. 8th Int. Conf. on Quantum Communication, Measurement and Computing (NICT Press, Tokyo) 363-368 Jul 2007 [Refereed][Invited]
Conventional solutions to the (Mean) King's problem without using entanglement have been investigated by Aravind [P. K. Aravind, ``Best conventional solutions to the King's problem'', Z. Naturforsch. 58a, 682 (2003)]. We report that the upper boun...
Conservation-law-induced quantum limits for physical realizations of the quantum NOT gate
Tokishiro Karasawa and Masanao Ozawa
Physical Review A 75(3) 032324/1-032324/16 Mar 2007 [Refereed]
Orthomodular logic represented by a complete orthomodular lattice has been studied as a pertinent generalization of the two-valued logic, Boolean-valued logic, and quantum logic. In this paper, we introduce orthomodular logic valued models for ...
Butsuri 64(5) 349-353 May 2009 [Refereed][Invited]
In his paper entitled "Studies on the Foundation of Quantum Mechanics. I" (1937), Kodi Husimi discovered the orthomodular law, a universally valid fundamental law of quantum logic. In the 1960's this replaced the modular law that von Neumann had p...
We propose a quantum authentication protocol that is robust against the theft of secret keys. In the protocol, disposable quantum passwords prevent impersonation attacks with stolen secret keys. The protocol also prevents the leakage of secret ...
Butsuri 59(3) 157-165 Mar 2004 [Refereed][Invited]
Classical mechanics leads to the deterministic view on the world, according to which the complete knowledge on the past state derives the complete knowledge on future values of physical quantities, whereas quantum mechanics shows that it is imposs...
Press Conference 18 Dec 2013 Tohoku University, Nagoya University
A research team led by Professor Keiichi Edamatsu, Research Institute of Electrical Communication at Tohoku University and Professor Masanao Ozawa, Graduate School of Information Science at Nagoya University has experimentally verified a violation...