Rényi entropy of a line in two-dimensional Ising models

Abstract

We consider the two-dimensional (2d) Ising model on a infinitely long cylinder and study the probabilities $p_i$ to observe a given spin configuration $i$ along a circular section of the cylinder. These probabilities also occur as eigenvalues of reduced density matrices in some Rokhsar-Kivelson wave-functions. We analyze the subleading constant to the Rényi entropy $R_n=1/(1-n)\ln ({\sum }_i{p}_i^n)$ and discuss its scaling properties at the critical point. Studying three different microscopic realizations, we provide numerical evidence that it is universal and behaves in a step-like fashion as a function of $n$, with a discontinuity at the Shannon point $n=1$. As a consequence, a field theoretical argument based on the replica trick would fail to give the correct value at this point. We nevertheless compute it numerically with high precision. Two other values of the Rényi parameter are of special interest: $n=1/2$ and $n=\infty$ are related in a simple way to the Affleck-Ludwig boundary entropies associated to free and fixed boundary conditions respectively.

8 pages, 6 figures, 2 tables. To be submitted to Physical Review B

References in corpus (3)

• Entanglement entropy of 2D conformal quantum critical points: hearing the shape of a quantum drum
• Entanglement Entropy in the O(N) model
• Universal entanglement entropy in 2D conformal quantum critical points

Cited by in corpus (3)

• Entanglement spectrum of random-singlet quantum critical points
• Universal behavior of a bipartite fidelity at quantum criticality
• Geometric entanglement of critical XXZ and Ising chains and Affleck-Ludwig boundary entropies