scholarly journals INTERPLAY BETWEEN QUANTUM PHASE TRANSITIONS AND THE BEHAVIOR OF QUANTUM CORRELATIONS AT FINITE TEMPERATURES

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345032 ◽  
Author(s):  
T. WERLANG ◽  
G. A. P. RIBEIRO ◽  
GUSTAVO RIGOLIN
Keyword(s):  
Phase Transitions ◽  
Critical Point ◽  
Thermodynamic Limit ◽  
Quantum Discord ◽  
Quantum Phase Transitions ◽  
Quantum Correlations ◽  
Infinite Chain ◽  
Quantum Phase ◽  
Absolute Zero ◽  
Zero Temperature

We review the main results and ideas showing that quantum correlations at finite temperatures (T), in particular quantum discord, are useful tools in characterizing quantum phase transitions (QPT) that only occur, in principle, at the unattainable absolute zero temperature. We first review some interesting results about the behavior of thermal quantum discord for small spin-1/2 chains and show that they already give us important hints of the infinite chain behavior. We then study in detail and in the thermodynamic limit (infinite chains) the thermal quantum correlations for the XXZ and XY models, where one can clearly appreciate that the behavior of thermal quantum discord at finite T is a useful tool to spotlight the critical point of a QPT.

scholarly journals Quantum correlations in critical XXZ system and LMG model

2018 ◽  
Vol 16 (03) ◽  
pp. 1850029 ◽  
Author(s):  
Biao-Liang Ye ◽  
Bo Li ◽  
Xianqing Li-Jost ◽  
Shao-Ming Fei
Keyword(s):  
Phase Transitions ◽  
Nearest Neighbor ◽  
Quantum Phase Transitions ◽  
Quantum Correlations ◽  
Quantum Phase ◽  
Trace Distance ◽  
Quantum Uncertainty ◽  
Hartree Fock ◽  
Local Quantum Uncertainty ◽  
Local Quantum

We investigate the quantum phase transitions for the [Formula: see text] spin-1/2 chains via the quantum correlations between the nearest and next-to-nearest neighbor spins characterized by negativity, information deficit, trace distance discord and local quantum uncertainty. It is shown that all these correlations exhibit the quantum phase transitions at [Formula: see text]. However, only information deficit and local quantum uncertainty can demonstrate quantum phase transitions at [Formula: see text]. The analytical and numerical behaviors of the quantum correlations for the [Formula: see text] system are presented. We also consider quantum correlations in the Hartree–Fock ground state of the Lipkin–Meshkov–Glick (LMG) model.

scholarly journals Enhancing quantum phase transitions in the critical point of Extended TC-Dicke model via Stark effect

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ahmed Salah ◽  
A. S. Abdel-Rady ◽  
Abdel-Nasser A. Osman ◽  
Samia. S. A. Hassan
Keyword(s):  
Phase Transitions ◽  
Critical Point ◽  
Stark Effect ◽  
Quantum Phase Transitions ◽  
Quantum Phase ◽  
Dicke Model

scholarly journals QUANTUM DISCORD, DECOHERENCE AND QUANTUM PHASE TRANSITION

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345042 ◽  
Author(s):  
INDRANI BOSE ◽  
AMIT KUMAR PAL
Keyword(s):  
Quantum Information ◽  
Quantum Discord ◽  
Quantum Phase Transitions ◽  
Transverse Field ◽  
Quantum Correlations ◽  
Quantum Phase ◽  
Quantum Channels ◽  
Operator Formalism ◽  
Kraus Operator ◽  
Different Types

Quantum discord is a more general measure of quantum correlations than entanglement and has been proposed as a resource in certain quantum information processing tasks. The computation of discord is mostly confined to two-qubit systems for which an analytical calculational scheme is available. The utilization of quantum correlations in quantum information-based applications is limited by the problem of decoherence, i.e., the loss of coherence due to the inevitable interaction of a quantum system with its environment. The dynamics of quantum correlations due to decoherence may be studied in the Kraus operator formalism for different types of quantum channels representing system-environment interactions. In this review, we describe the salient features of the dynamics of classical and quantum correlations in a two-qubit system under Markovian (memoryless) time evolution. The two-qubit state considered is described by the reduced density matrix obtained from the ground state of a spin model. The models considered include the transverse-field XY model in one dimension, a special case of which is the transverse-field Ising model, and the XXZ spin chain. The quantum channels studied include the amplitude damping, bit-flip, bit-phase-flip and phase-flip channels. The Kraus operator formalism is briefly introduced and the origins of different types of dynamics discussed. One can identify appropriate quantities associated with the dynamics of quantum correlations which provide signatures of quantum phase transitions in the spin models. Experimental observations of the different types of dynamics are also mentioned.

Quantum phase transitions

2004 ◽  
Vol 174 (8) ◽  
pp. 853 ◽  
Author(s):  
Sergei M. Stishov
Keyword(s):  
Phase Transitions ◽  
Quantum Phase Transitions ◽  
Quantum Phase
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