Eur. Phys. J. B (2015) 88: 269
https://doi.org/10.1140/epjb/e2015-60391-y

Regular Article

Dimerized phase and entanglement in the one-dimensional spin-1 bilinear biquadratic model

¹ Department of Applied Physics, Xi’an Jiaotong University, Xi’an 710049, P.R. China
² School of Science, Xi’an Polytechnic University, Xi’an 710048, P.R. China
³ Laboratory of Forensic Medicine and Biomedical Information, Chongqing Medical University, Chongqing 400016, P.R. China

^a e-mail: chenaiminxa@163.com

Received: 17 May 2015
Received in final form: 29 July 2015
Published online: 21 October 2015

Abstract

Dimerized phase and quantum entanglement are investigated in the one-dimensional spin-1 bilinear biquadratic model. Employing the infinite matrix product state representation, groundstate wavefunctions are numerically obtained by using the infinite time evolving block decimation method in the infinite lattice system. From a bipartite entanglement measure of the groundstates, i.e., von Neumann entropy, the phase transition points can be clearly extracted. Moreover, the even-bond and odd-bond von Neumann entropies show two different values in the spontaneous dimerized phase. It implies that the quantum entanglement can distinguish the two degenerate groundstates. Then, we define a dimer entropy in the spontaneous dimerized phase. Comparing to the dimer order parameter, the dimer entropy can play a role of a local order parameter to characterize the spontaneous dimerized phase.