116 citations · 1.4k across the 130 of their papers we have counts for
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A classical limit of Grover's algorithm induced by dephasing: Coherence vs entanglement
Kazuo Fujikawa, C. H. Oh, Koichiro Umetsu
A new approach to the classical limit of Grover's algorithm is discussed by assuming a very rapid dephasing of a system between consecutive Grover's unitary operations, which drive…
Exact algebraic separability criterion for two-qubit systems
Kazuo Fujikawa, C. H. Oh
A conceptually simpler proof of the separability criterion for two-qubit systems, which is referred to as "Hefei inequality" in literature, is presented. This inequality gives a ne…
Separability criteria with angular and Hilbert space averages
Kazuo Fujikawa, C. H. Oh, Koichiro Umetsu +1
The practically useful criteria of separable states in are discussed. The equality $G({\bf a},{\bf b})= 4[\langle ψ|P({\bf a})\otimes P({\bf b})…
Uncertainty principle, Shannon-Nyquist sampling and beyond
Kazuo Fujikawa, Mo-Lin Ge, Yu-Long Liu +1
Donoho and Stark have shown that a precise deterministic recovery of missing information contained in a time interval shorter than the time-frequency uncertainty limit is possible.…
Hardy's Paradox and Measurement-disturbance Relations
Kazuo Fujikawa, C. H. Oh, Sixia Yu
We establish a quantitative relation between Hardy's paradox and the breaking of uncertainty principle in the sense of measurement-disturbance relations in the conditional measurem…
A hidden-variables version of Gisin's theorem
Kazuo Fujikawa, Koichiro Umetsu
It is generally assumed that {\em local realism} represented by a noncontextual and local hidden-variables model in such as the one used by Bell always gives rise to CHSH ine…