title: Quantum discord length is enhanced while entanglement length is not by introducing disorder in a spin chain.
abstract: Classical correlation functions of ground states typically decay exponentially and polynomially, respectively, for gapped and gapless short-range quantum spin systems. In such systems, entanglement decays exponentially even at the quantum critical points. However, quantum discord, an information-theoretic quantum correlation measure, survives long lattice distances. We investigate the effects of quenched disorder on quantum correlation lengths of quenched averaged entanglement and quantum discord, in the anisotropic XY and XYZ spin glass and random field chains. We find that there is virtually neither reduction nor enhancement in entanglement length while quantum discord length increases significantly with the introduction of the quenched disorder.
authors: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors: Debasis
authors: D
authors: Sadhukhan
authors: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors: Sudipto Singha
authors: SS
authors: Roy
authors: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors: Debraj
authors: D
authors: Rakshit
authors: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors: R
authors: R
authors: Prabhu
authors: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors: Aditi
authors: A
authors: Sen De
authors: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors: Ujjwal
authors: U
authors: Sen