Tuning entanglement and ergodicity in two-dimensional spin systems using impurities and anisotropy
Date of this Version4-13-2012
Tuning entanglement and ergodicity in two-dimensional spin systems using impurities and anisotropy Gehad Sadiek, Qing Xu, and Sabre Kais Phys. Rev. A 85, 042313 (13 April 2012)
We consider the entanglement in a two-dimensional XY model in an external magnetic field h. The model consists of a set of seven localized spin-1/2 particles in a two-dimensional triangular lattice coupled through nearest-neighbor exchange interaction J. We examine the effect of single and double impurities in the system as well as the degree of anisotropy on the nearest-neighbor entanglement and ergodicity of the system. We have found that the entanglement of the system at the different degrees of anisotropy mimics that of the one-dimensional spin systems at the extremely small and large values of the parameter lambda = h/J. The entanglement of the Ising and partially anisotropic systems shows phase transition in the vicinity of lambda = 2, whereas, the entanglement of the isotropic system suddenly vanishes there. Also, we investigate the dynamic response of the system containing single and double impurities to an external exponential magnetic field at different degrees of anisotropy. We have demonstrated that the ergodicity of the system can be controlled by varying the strength and location of the impurities as well as the degree of anisotropy of the coupling.
Nanoscience and Nanotechnology