Excited-state entanglement and thermal mutual information in random spin chains

Article

关键词: ANTI-FERROMAGNETIC CHAIN;    MANY-BODY SYSTEMS;    QUANTUM;    ENTROPY;   

DOI  :  10.1103/PhysRevB.90.220202

来源: SCIE

【 摘 要 】

Entanglement properties of excited eigenstates (or of thermal mixed states) are difficult to study with conventional analytical methods. We approach this problem for random spin chains using a recently developed real-space renormalization group technique for excited states (RSRG-X). For the random XX and quantum Ising chains, which have logarithmic divergences in the entanglement entropy of their (infinite-randomness) critical ground states, we show that the entanglement entropy of excited eigenstates retains a logarithmic divergence while the mutual information of thermal mixed states does not. However, in the XX case the coefficient of the logarithmic divergence extends from the universal ground-state value to a universal interval due to the degeneracy of excited eigenstates. These models are noninteracting in the sense of having free-fermion representations, allowing strong numerical checks of our analytical predictions.

【 授权许可】

Free