Quantum coherence and correlation dynamics of two-qubit system in spin bath environment

2020 ◽  
Vol 29 (4) ◽  
pp. 040303
Author(s):  
Hao Yang ◽  
Li-Guo Qin ◽  
Li-Jun Tian ◽  
Hong-Yang Ma
Keyword(s):  
Quantum Coherence ◽  
Spin Bath ◽  
Qubit System

scholarly journals Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdel-Baset A. Mohamed ◽  
Hichem Eleuch
Keyword(s):  
Phase Space ◽  
Quantum Coherence ◽  
Coupling Constants ◽  
Light Quantum ◽  
Wehrl Entropy ◽  
Intrinsic Decoherence ◽  
Highly Sensitive ◽  
Qubit System ◽  
Probability Information ◽  
Q Function

AbstractWe explore the phase space quantum effects, quantum coherence and non-classicality, for two coupled identical qubits with intrinsic decoherence. The two qubits are in a nonlinear interaction with a quantum field via an intensity-dependent coupling. We investigate the non-classicality via the Wigner functions. We also study the phase space information and the quantum coherence via the Q-function, Wehrl density, and Wehrl entropy. It is found that the robustness of the non-classicality for the superposition of coherent states, is highly sensitive to the coupling constants. The phase space quantum information and the matter-light quantum coherence can be controlled by the two-qubit coupling, initial cavity-field and the intrinsic decoherence.

Frozen Quantum Coherence for a Central Two-Qubit System in a Spin-Chain Environment

2018 ◽  
Vol 35 (8) ◽  
pp. 080301
Author(s):  
Yang Yang ◽  
An-Min Wang ◽  
Lian-Zhen Cao ◽  
Jia-Qiang Zhao ◽  
Huai-Xin Lu
Keyword(s):  
Spin Chain ◽  
Quantum Coherence ◽  
Qubit System

scholarly journals Thermal Quantum Coherence properties in Two-Qubit Heisenberg XXX Model in Nonhomogeneous Magnetic Field

2021 ◽  
Author(s):  
Asad Ali ◽  
Muhammad Anees Khan
Keyword(s):  
Magnetic Field ◽  
Quantum Coherence ◽  
Uniform Magnetic Field ◽  
Coupling Parameter ◽  
Magnetic Interaction ◽  
Threshold Value ◽  
Quantum Correlations ◽  
Qubit System ◽  
Xxx Model ◽  
Heisenberg Xxx Model

We investigate the behavior of thermal quantum coherence in the Heisenberg XXX model for a two-qubit system placed in independently controllable Inhomogeneous magnetic fields applied to two qubits respectively. We discuss the behavior of quantum coherence by systematically varying the coupling parameter, magnetic field, and temperature for both ferromagnetic and antiferromagnetic cases. The results show the interesting behavior of quantum coherence in a certain range of parameters. Generally, it is observed that quantum correlations decay with temperature, but in the ferromagnetic case with uniform magnetic interaction, it rises with temperature up to a certain threshold value and ultimately it decreases its value to zero. Moreover, it is observed that preserving the quantum coherence for small temperatures is very hard with the increasing magnetic field because, at small temperatures, quantum coherence decays sharply with the increase in magnetic field whereas at larger temperatures it decays completely at fairly large values of the magnetic field. The variation of quantum coherence with uniform magnetic field in the antiferromagnetic case is observed to be Gaussian for larger temperature but at zero or nearly zero temperature, it behaves as a constant function for uniform magnetic field up to a threshold value and then decays to zero with an infinite slope. This shows the signature of quantum phase transition from quantum nature to classicality.

Nonlocal advantage of quantum coherence under relativistic frame

2018 ◽  
Vol 32 (31) ◽  
pp. 1850377 ◽  
Author(s):  
Long-Fei Wang ◽  
Ming-Ming Du ◽  
Wen-Yang Sun ◽  
Dong Wang ◽  
Liu Ye
Keyword(s):  
Sudden Death ◽  
Quantum Coherence ◽  
Quantum Discord ◽  
Thermal Noise ◽  
Unruh Effect ◽  
Qubit System ◽  
Bell Nonlocality ◽  
Better Than

In this paper, we investigate the influence of the Unruh effect on the achievement of the nonlocal advantage of quantum coherence for a two-qubit system under a relativistic frame. The results show that with the increase of acceleration, it is difficult to realize the nonlocal advantage of quantum coherence and when the acceleration exceeds a certain value, nonlocal advantage of quantum coherence cannot be realized. In addition, we explore the dynamics of Bell nonlocality, steering, quantum coherence, entanglement and quantum discord (QD) under Unruh thermal noise. It is shown that nonlocal advantage of quantum coherence, Bell nonlocality, steering and entanglement experience “sudden death” for a finite acceleration, while quantum coherence and QD vanish only in the limit of an infinite acceleration. We also find that not all nonlocal states can achieve the nonlocal advantage of quantum coherence. It is also demonstrated that the robustness of Bell nonlocality is better than nonlocal advantage of quantum coherence under the influence of the Unruh noise.

scholarly journals Heat Modulation on Target Thermal Bath via Coherent Auxiliary Bath

Entropy ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1183
Author(s):  
Wen-Li Yu ◽  
Tao Li ◽  
Hai Li ◽  
Yun Zhang ◽  
Jian Zou ◽  
...  
Keyword(s):  
Thermal Management ◽  
Coupling Strength ◽  
Quantum Coherence ◽  
Thermal Bath ◽  
Heat Current ◽  
Heat Management ◽  
Multifunctional Device ◽  
Qubit System ◽  
New Perspective ◽  
Steady Heat

We study a scheme of thermal management where a three-qubit system assisted with a coherent auxiliary bath (CAB) is employed to implement heat management on a target thermal bath (TTB). We consider the CAB/TTB being ensemble of coherent/thermal two-level atoms (TLAs), and within the framework of collision model investigate the characteristics of steady heat current (also called target heat current (THC)) between the system and the TTB. It demonstrates that with the help of the quantum coherence of ancillae the magnitude and direction of heat current can be controlled only by adjusting the coupling strength of system-CAB. Meanwhile, we also show that the influences of quantum coherence of ancillae on the heat current strongly depend on the coupling strength of system—CAB, and the THC becomes positively/negatively correlated with the coherence magnitude of ancillae when the coupling strength below/over some critical value. Besides, the system with the CAB could serve as a multifunctional device integrating the thermal functions of heat amplifier, suppressor, switcher and refrigerator, while with thermal auxiliary bath it can only work as a thermal suppressor. Our work provides a new perspective for the design of multifunctional thermal device utilizing the resource of quantum coherence from the CAB.

scholarly journals Coherence Trapping in Open Two-Qubit Dynamics

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2445
Author(s):  
Mariam Algarni ◽  
Kamal Berrada ◽  
Sayed Abdel-Khalek ◽  
Hichem Eleuch
Keyword(s):  
Quantum Coherence ◽  
Open Quantum Systems ◽  
Dynamical Behavior ◽  
Quantum Systems ◽  
Completely Positive Maps ◽  
L1 Norm ◽  
Separable States ◽  
System Parameters ◽  
Quantum Dynamical ◽  
Qubit System

In this manuscript, we examine the dynamical behavior of the coherence in open quantum systems using the l1 norm. We consider a two-qubit system that evolves in the framework of Kossakowski-type quantum dynamical semigroups (KTQDSs) of completely positive maps (CPMs). We find that the quantum coherence can be asymptotically maintained with respect to the values of the system parameters. Moreover, we show that the quantum coherence can resist the effect of the environment and preserve even in the regime of long times. The obtained results also show that the initially separable states can provide a finite value of the coherence during the time evolution. Because of such properties, several states in this type of environments are good candidates for incorporating quantum information and optics (QIO) schemes. Finally, we compare the dynamical behavior of the coherence with the entire quantum correlation.

Freezing Phenomenon of Quantum Coherence for a Two-qubit System Coupled to Ising Spin Chain

2018 ◽  
Vol 24 (3) ◽  
pp. 283-287
Author(s):  
杨阳 YANG Yang ◽  
曹连振 CAO Lian-zhen ◽  
赵加强 ZHAO Jia-qiang ◽  
逯怀新 LU Huai-xin
Keyword(s):  
Spin Chain ◽  
Quantum Coherence ◽  
Ising Spin ◽  
Qubit System

scholarly journals COHERENCE CONSERVATION OF A QUBIT COUPLED TO A DISSIPATING THERMAL ENVIRONMENT

2008 ◽  
Vol 06 (supp01) ◽  
pp. 779-785
Author(s):  
ROBABEH RAHIMI ◽  
AKIRA SAITOH ◽  
MIKIO NAKAHARA
Keyword(s):  
Thermal Equilibrium ◽  
Quantum Coherence ◽  
Thermal Environment ◽  
Model System ◽  
Qubit System ◽  
Analytical Proof

It is shown that quantum coherence is conserved in a principal system in the case that the system is coupled to a fast dissipating environment [arXiv:0709.0562]. The phenomenon is called the quantum wipe effect. Here, this effect is reviewed and the analytical proof for a model system consisting of a one-qubit system coupled to a fast dissipating environment is extended to an environment at a thermal equilibrium.

Entropy squeezing and coherence for a non-Markovian dissipative qubit system

2019 ◽  
Vol 35 (08) ◽  
pp. 2050046
Author(s):  
K. Berrada
Keyword(s):  
Quantum Coherence ◽  
Photonic Band Gap ◽  
Dynamical Behavior ◽  
Partial Coherence ◽  
Model Parameters ◽  
Entropy Squeezing ◽  
Qubit System ◽  
The Impact ◽  
Photonic Band ◽  
Gap Width

We examine the impact of the non-Markovian environment on the dynamical behavior of the quantum coherence and entropy squeezing considering a two-level atomic system (qubit) immersed in a reservoir with zero-temperature for two types of non-Markovian environments. We consider a cavity little off-resonance with the transition frequency of the qubit and the case of a non-perfect photonic band gap (PBG). We show that the amount of coherence is dependent on the structure of the environment and influenced through the memory effects. We obtain that the delay and revival of the coherence loss might take place by controlling the detuning of the cavity-qubit system. Whereas, a partial coherence trapping occurs in non-ideal PBG and the decrease of the gap width will destroy the coherence. On the other hand, we show the situation for which the squeezing is occurring and enhanced with respect to the main parameters for the system. Finally, we display the monotonic dependence of the quantum coherence and squeezing on the main model parameters.

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