Survival of time-evolved quantum correlations depending on whether quenching is across a critical point in an XY spin chain

Utkarsh Mishra, Debraj Rakshit, and R. Prabhu
Phys. Rev. A 93, 042322 – Published 15 April 2016

Abstract

The time dynamics of quantum correlations in the quantum transverse anisotropic XY spin chain of infinite length is studied at zero and finite temperatures. The evolution occurs due to the instantaneous quenching of the coupling constant between the nearest-neighbor spins of the model, which is performed either within the same phase or across the quantum phase-transition point connecting the order-disorder phases of the model. We characterize the time-evolved quantum correlations, viz., entanglement and quantum discord, which exhibit varying behavior depending on the initial state and the quenching scheme. We show that the system is endowed with enhanced nearest-neighbor bipartite quantum correlations compared to that of the initial state, when quenched from the ordered to the deep disordered phase. However, nearest-neighbor quantum correlations are almost washed out when the system is quenched from the disordered to the ordered phase with the initial state being at the zero temperature. We also identify the condition for the occurrence of enhanced bipartite correlations when the system is quenched within the same phase. Moreover, we investigate the bipartite quantum correlations when the initial state is a thermal equilibrium state with finite temperature, which reveals the effects of thermal fluctuation on the phenomena observed at zero temperature. Finally, an analogous analysis is carried out for zero-temperature next-nearest-neighbor quantum correlations.

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  • Received 26 October 2015
  • Revised 2 February 2016

DOI:https://doi.org/10.1103/PhysRevA.93.042322

©2016 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & Technology

Authors & Affiliations

Utkarsh Mishra1, Debraj Rakshit1, and R. Prabhu1,2,3,*

  • 1Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019, India
  • 2Department of Physics, Ben-Gurion University of the Negev, Beersheba 8410501, Israel
  • 3Department of Physics, Indian Institute of Technology Patna, Bihta 801103, Bihar, India

  • *prabhurama@iitp.ac.in

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Issue

Vol. 93, Iss. 4 — April 2016

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