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

Communications in Theoretical Physics

Robustness of Entanglement During Decoherence

Kwang-Il Kim, Bao‐Kui Zhao, Hong-Mei Li, Jingbin Lu

Published Nov 1, 2014• 6 citations
Publisher

Abstract

Finding the most robust entangled states during the whole process of decoherence is a particularly fundamental problem for quantum physics and quantum information processing. In this paper, the decoherence process of two-qubit system under two individual identical decoherence channels is investigated systematically. We find that although the robustness of two-qubit states with same initial entanglement is usually different, the Bell-like states are always the most robust entangled states during decoherence. That is to say, affected by the same amount of noise, the remain entanglement of an arbitrary two-qubit state is not more than that of a Bell-like state with the same initial entanglement.

DOI
10.1088/0253-6102/62/5/06

Related papers

Most Robust and Fragile States with the Same Entanglement Properties

Hongmei Li, Bao‐Kui Zhao

Abstract Finding the most robust entangled states and the most fragile entangled states during the whole process of decoherence is particularly a fundamental problem for quantum physics and quantum information processing. Here the robustness of three‐qubit states under three different decoherence channels (amplitude damping, dephasing, bit flip) systematically are investigated, and the most robust genuine tripartite entangled states and the most fragile ones during each of the three decoherence processes are found. Moreover, the states with the most significant difference in robustness are shown to be locally unitarily equivalent to each other and therefore contain the same entanglement properties.

Annalen der Physik•Sep 3, 2018•3 citations

Robustness of highly entangled multiqubit states under decoherence

Antoni Borràs, A. P. Majtey, Angel Ricardo Plastino +2 more

We investigate the decay of entanglement, due to decoherence, of multiqubit systems that are initially prepared in highly (in some cases maximally) entangled states. We assume that during the decoherence processes each qubit of the system interacts with its own independent environment. We determine, for systems with a small number of qubits and for various decoherence channels, the initial states exhibiting the most robust entanglement. We also consider a restricted version of this robustness-optimization problem that only involves states equivalent, under local unitary transformations, to the Greenberger-Horne-Zeilinger $|\text{GHZ}⟩$ state.

arXiv:0806.0779•Physical Review A•Feb 9, 2009•67 citations

Entanglement Dynamics of Two Qubits Coupled to a Noise Environment

Liu Jin, Shao-Hua Xiang, Cui Hui-Ping +1 more

We study the time evolution of two two-state systems (two qubits) initially in the pure entangled states or the maximally entangled mixed states interacting with the individual environmental noise. It is shown that due to environment noise, all quantum entangled states are very fragile and become a classical mixed state in a short-time limit. But the environment can affect entanglement in very different ways. The type of decoherence process for certain entangled states belongs to amplitude damping, while the others belong to dephasing decoherence.

Communications in Theoretical Physics•Apr 1, 2009•2 citations

Phonon decoherence of quantum entanglement: Robust and fragile states

T. Yu, Joseph H. Eberly

We study the robustness and fragility of entanglement of open quantum systems in some exactly solvable models in which the decoherence is caused by a pure dephasing process. In particular, for the toy models presented in this paper, we identify two different time scales, one is responsible for local dephasing, while the other is for entanglement decay. For a class of fragile entangled states defined in this paper, we find that the entanglement of two qubits, as measured by concurrence, decays faster asymptotically than the quantum dephasing of an individual qubit.

arXiv:quant-ph/0209037•Physical review. B, Condensed matter•Nov 13, 2002•187 citations

Entanglement and Decoherence: Fragile and Robust Entanglement

Jaroslav Novotný, G. Alber, Igor Jex

The destruction of entanglement of open quantum systems by decoherence is investigated in the asymptotic long-time limit. For this purpose a general and analytically solvable decoherence model is presented which does not involve any weak-coupling or Markovian assumption. It is shown that two fundamentally different classes of entangled states can be distinguished and that they can be influenced significantly by two important environmental properties, namely, its initially prepared state and its size. Quantum states of the first class are fragile against decoherence so that they can be disentangled asymptotically even if coherences between pointer states are still present. Quantum states of the second type are robust against decoherence. Asymptotically they can be disentangled only if also decoherence is perfect. A simple criterion for identifying these two classes on the basis of two-qubit entanglement is presented.

arXiv:1103.3318•Physical Review Letters•Aug 23, 2011•20 citations

Entanglement dynamics in the presence of controlled unital noise

A. Shaham, A. Halevy, L. Dovrat +2 more

Quantum entanglement is notorious for being a very fragile resource. Significant efforts have been put into the study of entanglement degradation in the presence of a realistic noisy environment. Here, we present a theoretical and an experimental study of the decoherence properties of entangled pairs of qubits. The entanglement dynamics of maximally entangled qubit pairs is shown to be related in a simple way to the noise representation in the Bloch sphere picture. We derive the entanglement level in the case when both qubits of a Bell state are transmitted through any arbitrary unital Pauli channel, and compare it to the case when the channel is applied only to one of the qubits. The dynamics of both cases was verified experimentally using an all-optical setup. We further investigated the evolution of partially entangled initial states. Different dynamics was observed for initial mixed and pure states of the same entanglement level.

arXiv:1405.7314•Scientific Reports•Jun 10, 2015•11 citations
Finding the most robust entangled states during the whole process of decoherence is a particularly fundamental problem for quantum physics and quantum information processing. In this paper, the decoherence process of two-qubit system under two individual identical decoherence channels is investigated systematically. We find that although the robustness of two-qubit states with same initial entanglement is usually different, the Bell-like states are always the most robust entangled states during decoherence. That is to say, affected by the same amount of noise, the remain entanglement of an arbitrary two-qubit state is not more than that of a Bell-like state with the same initial entanglement.
Abstract Finding the most robust entangled states and the most fragile entangled states during the whole process of decoherence is particularly a fundamental problem for quantum physics and quantum information processing. Here the robustness of three‐qubit states under three different decoherence channels (amplitude damping, dephasing, bit flip) systematically are investigated, and the most robust genuine tripartite entangled states and the most fragile ones during each of the three decoherence processes are found. Moreover, the states with the most significant difference in robustness are shown to be locally unitarily equivalent to each other and therefore contain the same entanglement properties.
We investigate the decay of entanglement, due to decoherence, of multiqubit systems that are initially prepared in highly (in some cases maximally) entangled states. We assume that during the decoherence processes each qubit of the system interacts with its own independent environment. We determine, for systems with a small number of qubits and for various decoherence channels, the initial states exhibiting the most robust entanglement. We also consider a restricted version of this robustness-optimization problem that only involves states equivalent, under local unitary transformations, to the Greenberger-Horne-Zeilinger ∣GHZ⟩|\text{GHZ}⟩∣GHZ⟩ state.
We study the time evolution of two two-state systems (two qubits) initially in the pure entangled states or the maximally entangled mixed states interacting with the individual environmental noise. It is shown that due to environment noise, all quantum entangled states are very fragile and become a classical mixed state in a short-time limit. But the environment can affect entanglement in very different ways. The type of decoherence process for certain entangled states belongs to amplitude damping, while the others belong to dephasing decoherence.
We study the robustness and fragility of entanglement of open quantum systems in some exactly solvable models in which the decoherence is caused by a pure dephasing process. In particular, for the toy models presented in this paper, we identify two different time scales, one is responsible for local dephasing, while the other is for entanglement decay. For a class of fragile entangled states defined in this paper, we find that the entanglement of two qubits, as measured by concurrence, decays faster asymptotically than the quantum dephasing of an individual qubit.
The destruction of entanglement of open quantum systems by decoherence is investigated in the asymptotic long-time limit. For this purpose a general and analytically solvable decoherence model is presented which does not involve any weak-coupling or Markovian assumption. It is shown that two fundamentally different classes of entangled states can be distinguished and that they can be influenced significantly by two important environmental properties, namely, its initially prepared state and its size. Quantum states of the first class are fragile against decoherence so that they can be disentangled asymptotically even if coherences between pointer states are still present. Quantum states of the second type are robust against decoherence. Asymptotically they can be disentangled only if also decoherence is perfect. A simple criterion for identifying these two classes on the basis of two-qubit entanglement is presented.
Quantum entanglement is notorious for being a very fragile resource. Significant efforts have been put into the study of entanglement degradation in the presence of a realistic noisy environment. Here, we present a theoretical and an experimental study of the decoherence properties of entangled pairs of qubits. The entanglement dynamics of maximally entangled qubit pairs is shown to be related in a simple way to the noise representation in the Bloch sphere picture. We derive the entanglement level in the case when both qubits of a Bell state are transmitted through any arbitrary unital Pauli channel, and compare it to the case when the channel is applied only to one of the qubits. The dynamics of both cases was verified experimentally using an all-optical setup. We further investigated the evolution of partially entangled initial states. Different dynamics was observed for initial mixed and pure states of the same entanglement level.