Average coherence and its monogamy in a two-dimensional XY model

Abstract

The critical behaviors of average coherence (AC) in a two-dimensional XY model are investigated by using the renormalization group method. It is found that there is an extremum for the AC of the renormalized blocks at the critical point of quantum phase transition (QPT), and a finite-scaling analysis shows that in the thermodynamic limit, there is a divergence for the AC susceptibility at the QPT point. Furthermore, by considering the bipartite division of the renormalized blocks, it is found that the AC is monogamous and the average correlated coherence is polygamous, and the corresponding monogamy score is also a reliable indicator of QPT. Some constraints on the shareability of AC among the renormalized blocks are also obtained.