The Quantum Correlation In The Heisenberg Spin System

It is a more traditional approach to study the quantum phase transition by the order parameter,and it is more popular to study the phase transition from the point of view of quantum information.Especially for strongly correlated quantum systems,it is very suitable to study the entanglement and correlation properties.This paper explores the quantum phase transition of antiferromagnetic quantum Heisenberg spin chain system from the perspective of quantum information,and focuses on the similarities and differences of the quantum correlation and quantum entanglement and various physical quantities in the phase of reflection.In order to achieve the purpose of the above study,we calculate the quantum discord of the antiferromagnetic Heisenberg spin chain quantum system and compared it with the calculations of correlation function,relative entropy of entanglement,concurrence,entanglement of form,reduced fidelity and the corresponding fidelity susceptibility.The results show that:(1)In the ground state and the first excited state,the quantum discord of the nearest neighbor and the next nearest neighbor is similar to the performance of the correlation function and the reduced fidelity,and can accurately reflect the quantum correlation property of the system.while the quantum entanglement do not have this feature and are only reliable at the nearest neighbor.(2)In the system,the quantum discord has a longer range of correlation and stronger anti-thermal noise than quantum entanglement.At the absolute zero or finite temperature,the nearest neighbor quantum entanglement disappears when the antiferromagnetic correlation of the next nearest neighbor increases to a certain extent,and the quantum entanglement of the next nearest neighbor occurs and slowly increased,but during this period the quantum discord of nearest neighbor and next nearest neighbor has always existed and will not disappear.