Tensor renormalization group approach to entanglement entropy

A bstract We propose a method to compute the entanglement entropy (EE) using the tensor renormalization group (TRG) method. The reduced density matrix of a d -dimensional quantum system is represented as a ( d + 1)-dimensional tensor network. We develop an explicit algorithm for d = 1 that enables the calculation of EE for single-interval subsystems of arbitrary size. We test our method in two-dimensional tensor network of the Ising model. The central charge is obtained as c = 0 . 49997(8) for D = 96, which agrees with the theoretical prediction within an error, demonstrating the accuracy and reliability of our proposed method.