author={Tanay Nag and Amit Kumar Dutta and Ayoti Patra},
  journal={International Journal of Modern Physics B},
We review recent studies on the measures of zero temperature quantum correlations namely, the quantum entanglement (concurrence) and discord present in the final state of a transverse XY spin chain following a quench through quantum critical points; the aim of these studies is to explore the scaling of the above quantities as a function of the quench rate. A comparative study between the concurrence and the quantum discord shows that their behavior is qualitatively the same though there are… 
7 Citations
Dynamical quantum correlations after sudden quenches
We employ the mean-field approach in the fermionic picture of the spin-1/2 XXZ chain to investigate the dynamics of bipartite quantum discord and concurrence under sudden quenching. In the case, when
Excess energy and decoherence factor of a qubit coupled to a one-dimensional periodically driven spin chain.
  • T. Nag
  • Physics, Medicine
    Physical review. E
  • 2016
This work analytically investigates the effect of system-environment coupling strength on the EEs and GFSS and relates the behavior of GFSS to EEs as a function of frequency by plausible analytical arguments and explicitly shows that the low-frequency beatinglike pattern of GF SS is an outcome of two frequencies, causing the oscillations in the two branches of EEs that are dependent on the coupling strength.
Measures and applications of quantum correlations
Quantum information theory is built upon the realisation that quantum resources like coherence and entanglement can be exploited for novel or enhanced ways of transmitting and manipulating
2 Low-Dimensional Quantum Spin Systems 1 . 2 . 1 Quantum Spin Models
  • 2016
Magnetism as a physical phenomenon has been known since antiquity but it was only after the advent of quantum mechanics that modern, microscopic theories of magnetism could be developed. Magnetism is
Quantum discord and its allies: a review of recent progress.
We review concepts and methods associated with quantum discord and related topics. We also describe their possible connections with other aspects of quantum information and beyond, including quantum
Lazy states, discordant states and entangled states for 2-qubit systems
We investigate the lazy states, entangled states and discordant states for 2-qubit systems. We show that many lazy states are discordant, many lazy states are entangled, and many mixed entangled
Coherent and dissipative dynamics at quantum phase transitions
The many-body physics at quantum phase transitions shows a subtle interplay between quantum and thermal fluctuations, emerging in the low-temperature limit. In this review, we first give a


Quantum discord in the ground and thermal states of spin clusters
Quantum discord (QD) is a general measure of bipartite quantum correlations with a potential role in quantum information processing tasks. Spin clusters serve as ideal candidates for the
Quantum discord for a central two-qubit system coupled to an XY-spin-chain environment
We investigate the dynamic behaviors of quantum discord for a central two-qubit system coupled to an XY-spin-chain environment. In the weak-coupling regime, we show that the quantum discord for the
Scaling of the decoherence factor of a qubit coupled to a spin chain driven across quantum critical points
We study the scaling of the decoherence factor of a qubit (spin-1/2) using the central spin model in which the central spin (qubit) is globally coupled to a transverse XY spin chain. The aim here is
Quantum Phase Transitions in Transverse Field Spin Models: From Statistical Physics to Quantum Information
The transverse field Ising and XY models (the simplest quantum spin models) provide the organising principle for the rich variety of interconnected subjects which are covered in this book. From a
Classical correlation and quantum discord in critical systems
We discuss the behavior of quantum and classical pairwise correlations in critical systems, with the quantumness of the correlations measured by the quantum discord. We analytically derive these
Quantum discord for two-qubit systems
Quantum discord, as introduced by Olliver and Zurek [Phys. Rev. Lett. 88, 017901 (2001)], is a measure of the discrepancy between two natural yet different quantum analogs of the classical mutual
Entropy and correlation functions of a driven quantum spin chain (15 pages)
We present an exact solution for a quantum spin chain driven through its critical points. Our approach is based on a many-body generalization of the Landau-Zener transition theory, applied to a
Scaling of entanglement close to a quantum phase transition
It is demonstrated, for a class of one-dimensional magnetic systems, that entanglement shows scaling behaviour in the vicinity of the transition point, which connects the theory of critical phenomena with quantum information by exploring the entangling resources of a system close to its quantum critical point.
Thermal quantum and classical correlations and entanglement in the XY spin model with three-spin interaction
Pairwise quantum discord (QD) and classical correlation (CC) are studied in the XY spin chain with three-spin interaction. We analyze their capability in detecting quantum phase transitions (QPTs) at
Dynamics of entanglement in one-dimensional spin systems (24 pages)
We study the dynamics of quantum correlations in a class of exactly solvable Ising-type models. We analyze in particular the time evolution of initial Bell states created in a fully polarized