Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Non-Markovian effects on quantum-communication protocols

Ye Yeo, Jun‐Hong An, C. H. Oh

Published Sep 30, 2010• 25 citations
Publisher

Abstract

We show how, under the influence of non-Markovian environments, two different maximally entangled Bell states give rise to states that have equal classical correlations and the same capacities to violate the Bell-Clauser-Horne-Shimony-Holt inequality, but intriguingly differing usefulness for teleportation and dense coding. We elucidate how different entanglement measures like negativity and concurrence, and two different measures of quantum discord, could account for these behaviors. In particular, we explicitly show how the Ollivier-Zurek measure of discord directly accounts for one state being a better resource for dense coding compared to another. Our study leads to several important issues about these measures of discord.

DOI
10.1103/physreva.82.032340

Related papers

QUANTUM CORRELATIONS AT FINITE TEMPERATURE

Liang Qiu

We show that, under the influence of finite temperature reservoirs, for a board class of states, Bell nonlocality always endures sudden death. Furthermore, for two states evolved from two different maximally entangled states, the larger the concurrence and quantum discord, the better the resource for dense coding. However, the more usefulness of a state for teleportation could not be owed to the larger negativity and geometric measure of discord.

International Journal of Quantum Information•Mar 1, 2012•2 citations

Non-Markovian effects on entanglement swapping

Jin Woo Jun

We show that, under the influence of non-Markovian environments on the entanglement swapping protocol, the maximally entangled antisymmetric Bell state produces more entanglement between the two final particles than the maximally entangled symmetric Bell state. We elucidate how negativity, concurrence, and geometric discord could account for this behavior.

Journal of the Korean Physical Society•Feb 1, 2012•2 citations

Maximal Violation of Bell Inequality and Correlations for Werner State

Song Shi-xue

The maximal violation of Bell inequality and correlations measured by mutual information and relative entropy for the Werner state are calculated.It is found that the measurements that result in the maximal violation of Bell inequality can extract the most information from the Werner state;in the two kinds of measures of correlation,quantum discord is all greater than classical correlation,whereas entanglement does not necessarily greater than classical correlation even in the case of the maximal violation of Bell inequality,which means that quantum discord can describe the nonlocality of correlation much better than entanglement so that makes it have wider application in quantum communication and quantum computation.

Journal of University of Jinan•Jan 1, 2011•0 citations

A Comparison of the Attempts of Quantum Discord and Quantum Entanglement to Capture Quantum Correlations

Asma Al-Qasimi, Daniel F. V. James

Measurements of Quantum Systems disturb their states. To quantify this non-classical characteristic, Zurek and Ollivier introduced the quantum discord, a quantum correlation which can be nonzero even when entanglement in the system is zero. Discord has aroused great interest as a resource that is more robust against the effects of decoherence and offers exponential speed up of certain computational algorithms. Here, we study general two-level bipartite systems and give general results on the relationship between discord, entanglement, and linear entropy, and identify the states for which discord takes a maximal value for a given entropy or entanglement, thus placing strong bounds on entanglement-discord and entropy-discord relations. We find out that although discord and entanglement are identical for pure states, they differ when generalized to mixed states as a result of the difference in the method of generalization.

arXiv:1007.1814•Jul 12, 2010•3 citations

A study of quantum correlations in open quantum systems

Indranil Chakrabarty, Subhashish Banerjee, Nana Siddharth

In this work, we study quantum correlations in mixed states. The states studied are modeled by a two-qubit system interacting with its environment via a quantum non demolition (purely dephasing) as well as dissipative type of interaction. The entanglement dynamics of this two qubit system is analyzed. We make a comparative study of various measures of quantum correlations, like Concurrence, Bell's inequality, Discord and Teleportation fidelity, on these states, generated by the above evolutions. We classify these evoluted states on basis of various dynamical parameters like bath squeezing parameter $r$, inter-qubit spacing $r_{12}$, temperature $T$ and time of system-bath evolution $t$. In this study, in addition we report the existence of entangled states which do not violate Bell's inequality, but can still be useful as a potential resource for teleportation. Moreover we study the dynamics of quantum as well as classical correlation in presence of dissipative coherence.

Quantum Information and Computation•Jul 1, 2011•17 citations

A study of Quantum Correlations in Open Quantum Systems

Indranil Chakrabarty, Subhashish Banerjee, Nana Siddharth

In this work, we study quantum correlations in mixed states. The states studied are modeled by a two-qubit system interacting with its environment via a quantum non demolition (purely dephasing) as well as dissipative type of interaction. The entanglement dynamics of this two qubit system is analyzed. We make a comparative study of various measures of quantum correlations, like Concurrence, Bell's inequality, Discord and Teleportation fidelity, on these states, generated by the above evolutions. We classify these evoluted states on basis of various dynamical parameters like bath squeezing parameter $r$, inter-qubit spacing $r_{12}$, temperature $T$ and time of system-bath evolution $t$. In this study, in addition we report the existence of entangled states which do not violate Bell's inequality, but can still be useful as a potential resource for teleportation. Moreover we study the dynamics of quantum as well as classical correlation in presence of dissipative coherence.

arXiv:1006.1856•Jun 9, 2010•0 citations
We show how, under the influence of non-Markovian environments, two different maximally entangled Bell states give rise to states that have equal classical correlations and the same capacities to violate the Bell-Clauser-Horne-Shimony-Holt inequality, but intriguingly differing usefulness for teleportation and dense coding. We elucidate how different entanglement measures like negativity and concurrence, and two different measures of quantum discord, could account for these behaviors. In particular, we explicitly show how the Ollivier-Zurek measure of discord directly accounts for one state being a better resource for dense coding compared to another. Our study leads to several important issues about these measures of discord.
The maximal violation of Bell inequality and correlations measured by mutual information and relative entropy for the Werner state are calculated.It is found that the measurements that result in the maximal violation of Bell inequality can extract the most information from the Werner state;in the two kinds of measures of correlation,quantum discord is all greater than classical correlation,whereas entanglement does not necessarily greater than classical correlation even in the case of the maximal violation of Bell inequality,which means that quantum discord can describe the nonlocality of correlation much better than entanglement so that makes it have wider application in quantum communication and quantum computation.
Measurements of Quantum Systems disturb their states. To quantify this non-classical characteristic, Zurek and Ollivier introduced the quantum discord, a quantum correlation which can be nonzero even when entanglement in the system is zero. Discord has aroused great interest as a resource that is more robust against the effects of decoherence and offers exponential speed up of certain computational algorithms. Here, we study general two-level bipartite systems and give general results on the relationship between discord, entanglement, and linear entropy, and identify the states for which discord takes a maximal value for a given entropy or entanglement, thus placing strong bounds on entanglement-discord and entropy-discord relations. We find out that although discord and entanglement are identical for pure states, they differ when generalized to mixed states as a result of the difference in the method of generalization.
In this work, we study quantum correlations in mixed states. The states studied are modeled by a two-qubit system interacting with its environment via a quantum non demolition (purely dephasing) as well as dissipative type of interaction. The entanglement dynamics of this two qubit system is analyzed. We make a comparative study of various measures of quantum correlations, like Concurrence, Bell's inequality, Discord and Teleportation fidelity, on these states, generated by the above evolutions. We classify these evoluted states on basis of various dynamical parameters like bath squeezing parameter rrr, inter-qubit spacing r12r_{12}r12​, temperature TTT and time of system-bath evolution ttt. In this study, in addition we report the existence of entangled states which do not violate Bell's inequality, but can still be useful as a potential resource for teleportation. Moreover we study the dynamics of quantum as well as classical correlation in presence of dissipative coherence.
In this work, we study quantum correlations in mixed states. The states studied are modeled by a two-qubit system interacting with its environment via a quantum non demolition (purely dephasing) as well as dissipative type of interaction. The entanglement dynamics of this two qubit system is analyzed. We make a comparative study of various measures of quantum correlations, like Concurrence, Bell's inequality, Discord and Teleportation fidelity, on these states, generated by the above evolutions. We classify these evoluted states on basis of various dynamical parameters like bath squeezing parameter rrr, inter-qubit spacing r12r_{12}r12​, temperature TTT and time of system-bath evolution ttt. In this study, in addition we report the existence of entangled states which do not violate Bell's inequality, but can still be useful as a potential resource for teleportation. Moreover we study the dynamics of quantum as well as classical correlation in presence of dissipative coherence.