A universal approach to Renyi entropy of multiple disjoint intervals
Han-Qing Shi, Hai-Qing Zhang
We propose a universal approach to compute the Renyi entropy with generically multiple disjoint intervals from the swapping operations. The proposal is grounded in our observation that there is a striking similarity between the replica trick utilized in quantum field theory and the process of swapping operations. Consequently, the Renyi entropy of multiple disjoint intervals can be obtained by evaluating the expectation values of the swapping operator. As an application, we use our proposal to study the Renyi entropy of a one-dimensional transverse-field Ising model with two, three and four disjoint intervals. In particular, as the system is at the critical point, our results of the Renyi entropy are consistent with the analytical results from the conformal field theory. Remarkably, our approach can go beyond the critical regime where the analytical methods from conformal field theory can not apply.
arXiv:2411.18353•Physics Letters B•Mar 28, 2026•0 citations