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Concurrence and Quantum Discord in the Eigenstates of Chaotic and Integrable Spin Chains
Author(s) -
Ashouri Atefeh,
Mahdavifar Saeed,
Misguich Grégoire,
Vahedi Javad
Publication year - 2020
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.201900515
Subject(s) - integrable system , physics , spins , quantum chaos , eigenvalues and eigenvectors , quantum , spin (aerodynamics) , concurrence , chaotic , quantum mechanics , quantum entanglement , condensed matter physics , mathematical physics , quantum dynamics , artificial intelligence , computer science , thermodynamics
There has been some substantial research about the connections between quantum chaos and quantum correlations in many‐body systems. This paper discusses a specific aspect of correlations in chaotic spin models, through concurrence (CC) and quantum discord (QD). Numerical results obtained in the quantum chaos regime and in the integrable regime of spin‐1/2 chains are compared. The CC and QD between nearest‐neighbor pairs of spins are calculated for all energy eigenstates. The results show that, depending on whether the system is in a chaotic or integrable regime, the distribution of CC and QD are markedly different. On the other hand, in the integrable regime, states with the largest CC and QD are found in the middle of the spectrum, in the chaotic regime, the states with the strongest correlations are found at low and high energies at the edges of spectrum. Finite‐size effects are analyzed, and some of the results are discussed in the light of the eigenstate thermalization hypothesis.