摘要We reinvestigate the measures concerning the notion of duality of a quantum system (the ``quanton'') in an asymmetry two-way interferometer. A new measure of the which-way information is introduced, which is based on the fidelity F instead of the trace distance Q of the final states of the which-way detector. An improved inequality is derived to be V2≤(R02- P2)(1-F)2, which is more stringent than the previous one of V2≤q(1-P2)(1-Q2).
Abstract：We reinvestigate the measures concerning the notion of duality of a quantum system (the ``quanton'') in an asymmetry two-way interferometer. A new measure of the which-way information is introduced, which is based on the fidelity F instead of the trace distance Q of the final states of the which-way detector. An improved inequality is derived to be V2≤(R02- P2)(1-F)2, which is more stringent than the previous one of V2≤q(1-P2)(1-Q2).
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2009, Vol. 26 
