116 citations · 1.4k across the 130 of their papers we have counts for
6 papers · 1 filter
Linearity of quantum probability measure and Hardy's model
Kazuo Fujikawa, C. H. Oh, Chengjie Zhang
We re-examine d=4 hidden-variables-models for a system of two spin- particles in view of the concrete model of Hardy, who analyzed the criterion of entanglement without referr…
Spin Operator and Entanglement in Quantum Field Theory
Kazuo Fujikawa, C. H. Oh, Chengjie Zhang
Entanglement is studied in the framework of Dyson's S-matrix theory in relativistic quantum field theory, which leads to a natural definition of entangled states of a particle-anti…
Improved Error-Tradeoff and Error-Disturbance Relations
Xiao-Ming Lu, Sixia Yu, Kazuo Fujikawa +1
Heisenberg's uncertainty principle is quantified by error-disturbance tradeoff relations, which have been tested experimentally in various scenarios. Here we shall report improved…
Conditionally valid uncertainty relations
Kazuo Fujikawa
It is shown that the well-defined unbiased measurement or disturbance of a dynamical variable is not maintained for the precise measurement of the conjugate variable, independently…
Quantum Discord, CHSH Inequality and Hidden Variables -- Critical reassessment of hidden-variables models
Kazuo Fujikawa
Hidden-variables models are critically reassessed. It is first examined if the quantum discord is classically described by the hidden-variable model of Bell in the Hilbert space wi…
Aharonov-Bohm effect and geometric phases -- Exact and approximate topology
Kazuo Fujikawa
By analyzing an exactly solvable model in the second quantized formulation which allows a unified treatment of adiabatic and non-adiabatic geometric phases, it is shown that the to…