Entanglement and quantum phase transition of spin glass: A renormalization group approach

Using a renormalization group approach, we study the entanglement properties of two spin glass models: the XXZ Heisenberg (with Dzyaloshinskii-Moriya interaction) and Ising transverse field spin glasses. The concurrence for both models are obtained through the Kadanoff renormalization group (RG) approach with random J(i)(z) and J(i) respectively. The constant couplings in the RG flow are randomized through the Gaussian distribution. For Delta = 0 corresponding to a non-spin glass material, a first-order transition is expected. By varying Delta from 0.05 to 0.5, the spin glass effect broadens the sharp transition resulting in a second-order-like transition. The fluctuations in the average concurrence for the spin glass case as measured by the standard deviations is also a good indicator of quantum phase transition. (C) 2014 Elsevier B.V. All rights reserved.