MONOGAMY PROPERTIES OF QUANTUM DISCORD FOR A THREE-QUBIT ENTANGLED STATE

2013 ◽  
Vol 27 (07) ◽  
pp. 1350049 ◽  
Author(s):  
XUE-KE SONG ◽  
TAO WU ◽  
LIU YE
Keyword(s):  
Relative Entropy ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
The Other ◽  
Numerical Calculations ◽  
Entangled State ◽  
Geometric Quantum Discord ◽  
The Given

In this paper, we obtain the pairwise quantum discord for a three-qubit W-class state, and investigate the monogamy property of quantum discord by two different ways (relative entropy-based distance and geometric square-norm distance). Through numerical calculations, we find that a party cannot have maximal quantum correlations with the other two parties simultaneously. For the given state, the quantum correlation between particles 1 and 3 induces limitation on the quantum correlation between them and particle 2. Moreover, the result also shows that the geometric quantum discord of the given W-class state obeys the monogamy property while the entropy quantum discord violates.

QUANTUM CORRELATIONS IN THE ENTANGLEMENT DISTILLATION PROTOCOLS

2013 ◽  
Vol 11 (03) ◽  
pp. 1350029
Author(s):  
SHAO-XIONG WU ◽  
JUN ZHANG ◽  
CHANG-SHUI YU ◽  
HE-SHAN SONG
Keyword(s):  
Quantum Entanglement ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
The Other ◽  
Entangled States ◽  
Entanglement Distillation

We study the quantum correlations between source and target pairs in different protocols of entanglement distillation of one kind of entangled states. We find that there does not exist any quantum correlation in the standard recurrence distillation protocol, while quantum discord and even quantum entanglement are always present in the other two cases of the improved distillation protocols. In the three cases, the distillation efficiency improved with the quantum correlations enhanced.

Robustness of Quantum Correlations in Entangled Two su(2) Systems Non-mutually Interacting with su(1, 1) System under Intrinsic Decoherence

2018 ◽  
Vol 25 (03) ◽  
pp. 1850015
Author(s):  
A.-B. A. Mohamed ◽  
M. S. Abdalla ◽  
A.-S. F. Obada
Keyword(s):  
Steady State ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Bell State ◽  
Analytical Description ◽  
Quantum Correlations ◽  
Total System ◽  
Intrinsic Decoherence ◽  
Geometric Quantum Discord ◽  
Phase Decoherence

Two two-level systems generated by su(2) algebra are initially prepared in a maximum nonsymmetric Bell state and having no mutual interaction. Each su(2)-system spatially interacts with two-mode cavity field in the nondegenerate parametric amplifier type cast through operators governed by su(1, 1) Lie algebra. An analytical description for the time evolution of the final state of the total system with the effect of intrinsic decoherence is found. Therefore, the robustness of the quantum correlations between the two su(2)-system is investigated by means of geometric quantum discord, measurement-induced nonlocality and negativity. We analyze in some detail the influence of initial coherence intensities, detuning and phase decoherence parameters on the steady-state correlation. We find that the steady-state correlations can be generated and enhanced by controlling the parameters of: the initial coherence intensities, the Bargmman index and the detuning. It is shown that the phenomenon of sudden death and re-birth of entanglement, and the sudden changes of the geometric quantum correlation can be controlled by these parameters. We find that the robustness of the quantum correlation can be greatly enhanced by the Bargmman index and the resonance detuning. Negativity is the measure most susceptible to phase decoherence, while geometric quantum discord and measurement-induced nonlocality are the more robust measures.

Dynamics of quantum correlations in quantum teleportation

2020 ◽  
Vol 34 (10) ◽  
pp. 2050093
Author(s):  
K. El Anouz ◽  
I. El Aouadi ◽  
A. El Allati ◽  
T. Mourabit
Keyword(s):  
Quantum Teleportation ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Information Source ◽  
Dynamical Evolution ◽  
Single Mode ◽  
Quantum Correlations ◽  
Entangled State ◽  
Average Fidelity ◽  
Level Atom

A scheme of quantum teleportation using Jaynes–Cummings model is proposed. It consists of using a partial entangled state generated from the interaction between a two-level atom and single mode of radiation field as a quantum channel. By controlling the number of photons inside cavity and detuning parameter, the dynamical evolution of quantum correlation and entanglement degree in terms of quantum discord and concurrence, respectively, in the nonresonance case are investigated. Moreover, a comparative study between the teleported entanglement, teleported quantum correlation and average fidelity shows a good similarity between their dynamical evolution. Consequently, we conclude that quantum discord may be considered as a good information source in quantum teleportation process.

Dynamics of quantum correlations in a qubit-qutrit spin system under random telegraph noise

2021 ◽  
Author(s):  
Fadwa Benabdallah ◽  
Hamid Arian Zad ◽  
Mohammed Daoud ◽  
Nerses S Ananikian
Keyword(s):  
High Temperatures ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
Spin Model ◽  
Dimensionless Time ◽  
Random Telegraph Noise ◽  
Geometric Quantum Discord ◽  
Logarithmic Negativity ◽  
Telegraph Noise ◽  
Real Complex

Abstract We study the dimensionless time evolution of the logarithmic negativity and geometric quantum discord of a qubit-qutrit XXX spin model under the both Markovian and non-Markovian noise channels. We find that at a special temperature interval the quantum entanglement based on the logarithmic negativity reveals entanglement sudden deaths together with revivals. The revival phenomenon is due to the non-Markovianity resulting from the feedback effect of the environment. At high temperatures, the scenario of death and revival disappears. The geometric quantum discord evolves alternatively versus time elapsing with damped amplitudes until the system reaches steady state. It is demonstrated that the dynamics of entanglement negativity undergoes substantial changes by varying temperature, and it is much more fragile against the temperature rather than the geometric quantum discord. The real complex heterodinuclear [Ni(dpt (H2O)Cu(pba)]·2H2O [with pba =1,3-propylenebis(oxamato) and dpt = bis-(3-aminopropyl)amine] is an experimental representative of our considered bipartite qubit-qutrit system that may show remarkable entanglement deaths and revivals at relatively high temperatures and high magnetic field that is comparable with the strength of the exchange interaction J between Cu+2 and Ni+2 ions, i.e., kBT ≈ J and μBB ≈ J.

Improvement of quantum correlations by repetitive quantum error correction

2019 ◽  
Vol 17 (05) ◽  
pp. 1950044
Author(s):  
A. El Allati ◽  
H. Amellal ◽  
A. Meslouhi
Keyword(s):  
Error Correction ◽  
Quantum Correlation ◽  
Coherent States ◽  
Quantum Discord ◽  
Error Correcting Code ◽  
Quantum Correlations ◽  
Quantum Error Correction ◽  
Optical Field ◽  
Quantum Error ◽  
Entangled Coherent States

A quantum error-correcting code is established in entangled coherent states (CSs) with Markovian and non-Markovian environments. However, the dynamic behavior of these optical states is discussed in terms of quantum correlation measurements, entanglement and discord. By using the correcting codes, these correlations can be as robust as possible against environmental effects. As the number of redundant CSs increases due to the repetitive error correction, the probabilities of success also increase significantly. Based on different optical field parameters, the discord can withstand more than an entanglement. Furthermore, the behavior of quantum discord under decoherence may exhibit sudden death and sudden birth phenomena as functions of dimensionless parameters.

scholarly journals Geometric measures of discordlike quantum correlations based on Tsallis relative entropy

2019 ◽  
Vol 17 (04) ◽  
pp. 1950034
Author(s):  
Weijing Li
Keyword(s):  
Relative Entropy ◽  
Quantum Correlation ◽  
Quantum Correlations ◽  
Partial Coherence ◽  
Good Measure ◽  
Coherence Measure ◽  
Geometric Measure ◽  
Special Cases ◽  
Analytic Expression ◽  
Correlation Measures

A kind of new geometric measure of quantum correlations is formulated. The proposed formulation is in terms of the quantum Tsallis relative entropy and can naturally be viewed as a one-parameter extension quantum discordlike measure that satisfies all requirements of a good measure of quantum correlations. It is of an elegant analytic expression and contains several existing good quantum correlation measures as special cases. The partial coherence measure is also investigated.

QUANTUM DISCORD IN THE THERMAL STATES OF A SPIN-STAR SYSTEM

2011 ◽  
Vol 25 (30) ◽  
pp. 2289-2297 ◽  
Author(s):  
XIAO SAN MA ◽  
GUANG XING ZHAO ◽  
JIA YAN ZHANG ◽  
AN MIN WANG
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Anisotropy Parameter ◽  
Interaction Strength ◽  
The Other ◽  
Star System ◽  
Star Model ◽  
Thermal States

We investigate the quantum discord in the thermal states for a spin-star model consisting of three parties which include one central spin and the other two outer spins. Our results imply that the quantum correlation can be established between the two outer spins both of which interacting with the central spin independently. From the analysis, we find that the quantum discord and entanglement depends not only on the external magnetic field and the interaction strength but also on the anisotropy parameter and the temperature. Specially, the quantum discord is more robust than the quantum entanglement in the sense that the quantum discord lasts for higher temperatures than the entanglement does.

scholarly journals Quantum Entanglement and Quantum Discord of Two-Mode Gaussian States in a Thermal Environment

2011 ◽  
Vol 18 (02) ◽  
pp. 175-190 ◽  
Author(s):  
Aurelian Isar
Keyword(s):  
Sudden Death ◽  
Time Evolution ◽  
Quantum Entanglement ◽  
Quantum Discord ◽  
Thermal Environment ◽  
Quantum Correlations ◽  
Entangled State ◽  
Gaussian State ◽  
Thermal Bath ◽  
Bipartite State

In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous-variable quantum entanglement and quantum discord for a system consisting of two noninteracting modes embedded in a thermal environment. Entanglement and discord are used to quantify the quantum correlations of the system. For all values of the temperature of the thermal reservoir, an initially separable Gaussian state remains separable for all times. We study the time evolution of logarithmic negativity, which characterizes the degree of entanglement, and we show that in the case of an entangled initial Gaussian state, entanglement suppression (entanglement sudden death) takes place for non-zero temperatures of the environment. Only for zero temperature of the thermal bath the initial entangled state remains entangled for finite times. We analyze time evolution of Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and we show that quantum discord decays asymptotically in time under the effect of thermal bath. This is in contrast with the sudden death of entanglement. Before the suppression of entanglement, the qualitative evolution of quantum discord is very similar to that of the entanglement. We describe also time evolution of the degree of classical correlations and of quantum mutual information, which measures the total correlations of quantum system.

scholarly journals SUDDEN CHANGE OF QUANTUM DISCORD UNDER SINGLE QUBIT NOISE

2013 ◽  
Vol 11 (05) ◽  
pp. 1350048 ◽  
Author(s):  
LI-XING JIA ◽  
BO LI ◽  
R.-H. YUE ◽  
HENG FAN
Keyword(s):  
Quantum System ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Sudden Change ◽  
Entangled State ◽  
Noisy Environment ◽  
Noisy Environments ◽  
Single Qubit ◽  
Sudden Transition

We show that the sudden change of quantum correlation can occur even when only one part of the composite entangled state is exposed to a noisy environment. Our results are illustrated through the action of different noisy environments individually on a single qubit of quantum system. Composite noise on the whole of the quantum system is thus not the necessarily condition for the occurrence of sudden transition for quantum correlation.

scholarly journals Quantum Correlation Dynamics in Controlled Two-Coupled-Qubit Systems

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 785 ◽  
Author(s):  
Iulia Ghiu ◽  
Roberto Grimaudo ◽  
Tatiana Mihaescu ◽  
Aurelian Isar ◽  
Antonino Messina
Keyword(s):  
Time Evolution ◽  
Quantum Correlation ◽  
Quantum Dynamics ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
Initial State ◽  
Analytical Treatment ◽  
Werner State ◽  
Driven System ◽  
Physical Reasons

We study and compare the time evolutions of concurrence and quantum discord in a driven system of two interacting qubits prepared in a generic Werner state. The corresponding quantum dynamics is exactly treated and manifests the appearance and disappearance of entanglement. Our analytical treatment transparently unveils the physical reasons for the occurrence of such a phenomenon, relating it to the dynamical invariance of the X structure of the initial state. The quantum correlations which asymptotically emerge in the system are investigated in detail in terms of the time evolution of the fidelity of the initial Werner state.

Sign in / Sign up

Export Citation Format

Share Document