We address the dynamics of a two-qubit system interacting with a classical dephasing environment driven by a Gaussian stochastic process. Upon introducing the concept of entanglement-preserving time, we compare the degrading effects of different environments, e.g. those described by Ornstein–Uhlenbeck (OU) or fractional noise. In particular, we consider pure Bell states and mixtures of Bell states and study the typical values of the entanglement-preserving time for both independent and common environments. We found that engineering environments towards fractional Gaussian noise is useful to preserve entanglement as well as to improve its robustness against noise. We also address entanglement sudden death by studying the sudden-death time as a function of the initial negativity. We found that: (i) the sudden-death time is bounded from below by an increasing function of the initial negativity, (ii) the sudden-death time depends only slightly on the process used to describe the environment and exhibits typicality. Overall, our results show that engineering the environment has only a slight influence over the entanglement sudden-death time, while it represents a valuable resource to increase the entanglement-preserving time, i.e. to maintain entanglement closer to the initial level for a longer interaction time.We address the dynamics of a two-qubit system interacting with a classical dephasing environment driven by a Gaussian stochastic process. Upon introducing the concept of entanglement-preserving time, we compare the degrading effects of different environments, e.g. those described by Ornstein–Uhlenbeck (OU) or fractional noise. In particular, we consider pure Bell states and mixtures of Bell states and study the typical values of the entanglement-preserving time for both independent and common environments. We found that engineering environments towards fractional Gaussian noise is useful to preserve entanglement as well as to improve its robustness against noise. We also address entanglement sudden death by studying the sudden-death time as a function of the initial negativity. We found that: (i) the sudden-death time is bounded from below by an increasing function of the initial negativity, (ii) the sudden-death time depends only slightly on the process used to describe the environment and exhibits typicality. Overall, our results show that engineering the environment has only a slight influence over the entanglement sudden-death time, while it represents a valuable resource to increase the entanglement-preserving time, i.e. to maintain entanglement closer to the initial level for a longer interaction time.

arXiv:1408.3010International Journal of Quantum InformationOct 21, 201459 citations

A study on the sudden death of entanglement

H. T. Cui, Kai Li, X. X. Yi

arXiv:quant-ph/0612145Physics Letters ADec 23, 2006106 citations

Effects of quantum noises and noisy quantum operations on entanglement and special dense coding

Sylvanus Quek, Ziang Li, Ye Yeo

We show how noncommuting noises could cause a Bell state ${\ensuremath{\chi}}_{0}$ to suffer entanglement sudden death (ESD). ESD may similarly occur when a noisy operation acts, if the corresponding Hamiltonian and Lindblad operator do not commute. We study the implications of these in special dense coding $\mathcal{S}$ . When noises that cause ESD act, we show that ${\ensuremath{\chi}}_{0}$ may lose its capacity for $\mathcal{S}$ before ESD occurs. Similarly, ${\ensuremath{\chi}}_{0}$ may fail to yield information transfer better than classically possible when the encoding operations are noisy, though entanglement is not destroyed in the process.We show how noncommuting noises could cause a Bell state ${\ensuremath{\chi}}_{0}$ to suffer entanglement sudden death (ESD). ESD may similarly occur when a noisy operation acts, if the corresponding Hamiltonian and Lindblad operator do not commute. We study the implications of these in special dense coding $\mathcal{S}$. When noises that cause ESD act, we show that ${\ensuremath{\chi}}_{0}$ may lose its capacity for $\mathcal{S}$ before ESD occurs. Similarly, ${\ensuremath{\chi}}_{0}$ may fail to yield information transfer better than classically possible when the encoding operations are noisy, though entanglement is not destroyed in the process.

arXiv:0908.2520Physical Review AFeb 12, 201023 citations

\mathcal{S}

. When noises that cause ESD act, we show that ${\ensuremath{\chi}}_{0}$ may lose its capacity for

\mathcal{S}

before ESD occurs. Similarly, ${\ensuremath{\chi}}_{0}$ may fail to yield information transfer better than classically possible when the encoding operations are noisy, though entanglement is not destroyed in the process.