QUQNTUM DISCORD AND QUANTUM PHASE TRANSITION IN SPIN-1/2 FRUSTRATED HEISENBERG CHAIN
By using the concept of the quantum discord (QD), we study the spin-1/2 antiferro-magnetic Heisenberg chain with next-nearest-neighbor interaction. Due to the SU(2) symmetry and Z(2) symmetry in this system, we obtain the analytical result of the QD and its geometric measure (GMQD), which is determined by the two-site correlators. For the 4-site and 6-site cases, the connection between GMQD (QD) and the eigenenergies was revealed. From the analytical and numerical results, we find GMQD (QD) is an effective tool in detecting both the first-order and the infinite-order quantum-phase-transition points for the finite-size systems. Moreover, by using the entanglement excitation energy and a universal frustration measure we consider the frustration properties of the system and find a nonlinear dependence of the GMQD on the frustration.
quantum phase transition frustration quantum discord geometric measure of quantum discord