Disturbance-based measure of macroscopic coherence

Hyukjoon Kwon, Chae-Yeun Park, Kok Chuan Tan, Hyunseok Jeong
2017 New Journal of Physics  
We propose a measure of macroscopic coherence based on the degree of disturbance caused by a coarse-grained measurement. Based on our measure, we point out that recently proposed criteria of macroscopic coherence may lead to inconsistent results when considering certain states such as a product of microscopic superpositions. An inequality relation is proved that relates the Wigner-Yanase-Dyson skew information and the measurement disturbance, providing arguments as to why our approach is able
more » ... rule out such inconsistencies. We show that our measure can also quantify the fragility of a quantum state to a certain type of decoherence. Our work provides a general framework of quantifying macroscopic coherence from an operational point of view, based on the relationship between the precision of the measurement and disturbance of the quantum state.
doi:10.1088/1367-2630/aa68f5 fatcat:gubdafh2pbaubflwzqnfuyxrpy