title: Quantum correlations in quenched disordered spin models: Enhanced order from disorder by thermal fluctuations.
abstract: We investigate the behavior of quantum correlations of paradigmatic quenched disordered quantum spin models, viz., the XY spin glass and random-field XY models. We show that quenched averaged quantum correlations can exhibit the order-from-disorder phenomenon for finite-size systems as well as in the thermodynamic limit. Moreover, we find that the order-from-disorder can become more pronounced in the presence of temperature by suitable tuning of the system parameters. The effects are found for entanglement measures as well as for information-theoretic quantum correlation ones, although the former show them more prominently. We also observe that the equivalence between the quenched averages and their self-averaged cousins--for classical and quantum correlations--is related to the quantum critical point in the corresponding ordered system.
authors.affiliation: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors.forename: Debasis
authors.initials: D
authors.lastname: Sadhukhan
authors.affiliation: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors.forename: R
authors.initials: R
authors.lastname: Prabhu
authors.affiliation: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors.forename: Aditi
authors.initials: A
authors.lastname: Sen De
authors.affiliation: Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211 019, India.
authors.forename: Ujjwal
authors.initials: U
authors.lastname: Sen