An Inequality Concerning Quantitative Duality in an Asymmetry Two-Way Interferometer
Yang Han, Chun-Wang Wu, Wei Wu, Ping‐Xing Chen, Cheng-Zu Li · Chinese Physics Letters · 2009
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 ν 2 ≤ (R 2 0 – P 2 )(1 − F) 2 , which is more stringent than the previous one of ν 2 ≤ (1 − P 2 )(1 − Q 2 ).