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

Laser Physics Letters

Entanglement swapping under global noise environment

Fan‐Zhen Kong, Junlong Zhao, Jie Ji

Published Jul 14, 2023• 2 citations
Publisher

Abstract

Abstract We investigate the entanglement swapping under phase damping global noise and amplitude damping global noise. The two qubits the intermediate user holds during the entanglement swapping process first suffer from a global noise before the Bell measurement is carried out. Based on this assumption, the influence of global phase damping noise and global amplitude damping noise on the output entanglement of entanglement swapping is investigated, respectively. Our findings imply that the output entanglement is completely independent of the phase damping global noise and determined by the input entanglement when entanglement swapping is performed in a global phase damping noise environment. In addition, when entanglement swapping is executed in an amplitude damping environment, the output entanglement oscillates periodically with time, and the output entanglement may disappear at some points and reappear at others. In this case, we need not only to improve the input entanglement but also to control the evolution time of the amplitude damping global noise to ensure the optimal output entanglement. Our findings may help experimentalists to avoid and utilize environmental noise in entanglement swapping.

DOI
10.1088/1612-202x/ace2b4

Related papers

Generating a maximally entangled state via a pure global noise environment

Fan‐Zhen Kong, Junlong Zhao

Abstract We studied the entangling power of two pure global noises, i.e. amplitude damping noise and classic noise. The entangling power of the two-qubit amplitude damping global noise periodically oscillates with time. Additionally, the entangling power of two-qubit global classical noise increases exponentially with time. The maximum entangling power of both of them exceeds that of the perfect entanglers. Based on this, we propose the conditions for generating a maximally entangled state with global noise acting on a two-qubit separable state. Only if the two-qubit composite system, which is initially in one of those product states: 1 2 ( | 0 ⟩ ± | 1 ⟩ ) ⊗ 1 2 ( | 0 ⟩ ± | 1 ⟩ ) , | 10 ⟩ and | 01 ⟩ suffers an amplitude damping global noise, can we prepare this system in the maximally entangled state by appropriately controlling the evolution time of amplitude damping. Finally, we investigate the disentanglement of the maximum entangled Bell state using these two types of global noise. The two global noises cannot completely disentangle the Bell states Φ ± . Under the influence of amplitude damping global noise, the entanglement of Bell state Ψ + undergoes a cyclical variation, alternating between disappearance and recovery to reach maximum entanglement within one period. The entanglement of either Bell state Ψ + or Ψ − is completely independent of global classical noise. The entanglement of Bell state Ψ − is also robust against amplitude damping global noise.

Laser Physics Letters•Apr 3, 2024•1 citation

Entanglement swapping through the amplitude damping noise channel

Jianbo Xing, Fan Zhang

This paper investigates the degradation mechanism of the photon-number-encoded entanglement swapping protocol under the amplitude damping noise channel. By establishing a beam splitter physical model to simulate the energy dissipation process, the evolution density matrix of the input states [Formula: see text] and [Formula: see text] under independent noise channels is analytically derived, and the density matrix, fidelity, and concurrence of the target particle pair after entanglement swapping are presented. Furthermore, for the case where the initial states are maximally entangled states, this paper numerically simulates the variation curves of the fidelity and concurrence of the system after entanglement swapping with the noise parameter. The results show that as the noise intensity increases, both the fidelity and concurrence of the target system exhibit a decreasing trend. Simultaneously, due to the presence of noise, even if the input states are maximally entangled, the entanglement of the target system after swapping may be destroyed. Based on this, the study further deduces the constraint conditions required to maintain system entanglement in this scenario. Given the restrictive effect of these constraints on entanglement maintenance, this paper also specifically examines the fidelity and concurrence of the target state output from entanglement swapping in the case of 50 : 50 beam splitters when the input states are both maximally entangled. The research finds that in this case, since the constraints are not satisfied, even if the input states are maximally entangled, the entanglement of the output state completely disappears.

Scientific Reports•Feb 9, 2026•1 citation

Characterizing Entanglement in Combinations of Bell States through Superposition and Mixing: An Increase in Entanglement on Introducing Depolarizing, Phase Damping, and Amplitude Damping Noise

Nishant Chaudhari, Jean-François Van Huele

We systematically characterize quantum entanglement in all sixteen combinations of two-qubit Bell states across three operational regimes: pure superposition, noiseless mixing, and asymmetric mixing of one noisy and one pure Bell state. For pure superpositions, we calculate the von Neumann entropy and show that entanglement depends critically on the relative phase phi between superposed states. For mixed states, we use concurrence C under three physically motivated decoherence channels. The Depolarizing (DP) and Phase Damping (PD) channels are modeled as global, collective operations on the two-qubit Hilbert space, while Amplitude Damping (AD) is treated as independent local decay on each qubit, reflecting the asymmetric, energy-dissipating nature of spontaneous emission. A central and counterintuitive result is that increasing noise can raise concurrence in specific parameter regimes across all three channels. We further map the boundary between mathematical entanglement (C > 0) and operational quantum non-locality using the Horodecki criterion, finding this boundary to be strongly channel-dependent. Under Phase Damping, the Bell-local entanglement regime vanishes entirely for identical and same-bases mixtures, meaning any surviving entanglement guarantees a CHSH violation. Under Depolarizing noise, a large Bell-local region requires mixing probability r > 1/sqrt(2) to recover non-locality at maximum noise. For Amplitude Damping, certain mixtures exhibit a non-monotonic Horodecki parameter M(T): concurrence decreases monotonically with noise, yet the capacity for CHSH violation is lost at intermediate noise levels and restored at high noise, as maximal damping repurifies the noisy branch. These results provide a unified analytical reference for entanglement and non-locality management across Bell-state combinations and decoherence channels relevant to NISQ architectures.

quant-pharXiv:2608.17500•Aug 19, 2026•0 citations

Dynamics of nonlocality in bipartite quantum systems subjected to global noise environment

Fan‐Zhen Kong, Junlong Zhao

Abstract We investigate the Bell nonlocality dynamics of bipartite quantum systems under three distinct types of global decoherence environments: global amplitude damping noise, globally correlated classical noise, and global phase-damping noise. By combining numerical optimization techniques over Bell inequalities—specifically the Clauser–Horne–Shimony–Holt inequality—and describing the global noise-evolution process of a two-qubit system with the Kraus operator formalism, we systematically characterize the evolution of quantum nonlocality in a two-qubit system. Our results demonstrate that, under a global amplitude damping noise environment, precise temporal modulation of the amplitude damping channel enables the composite system to retain maximal Bell-nonlocal correlations in its final state. In contrast, globally correlated classical noise fields induce exponential suppression of Bell inequality violations. Remarkably, the systems subjected to global phase-damping noise exhibit pronounced robustness to nonlocality. These findings highlight the critical role of global noise in nonlocality dynamics.

Laser Physics Letters•Jul 1, 2025•0 citations

Environment-assisted entanglement purification

Liang Qiu, Zhi Liu, Xin Wang

Two qubits in a pure entangled state passing through and interacting with amplitude damping noises will cause the decay of entanglement. Entanglement swapping combined with environment measurement is proposed to purify entanglement of the two-qubit state. Some initial states can be purified into the maximally entangled ones by just using the protocol for one time, in contrast to iteratively using the protocol given in Phys. Rev. A 89, 014303 (2014).

Quantum Information and Computation•Sep 1, 2016•2 citations

Control of population and entanglement of two qubits under the action of different types of dissipative noise

Guilherme Jurkevicz Delben, A. L. O. dos Santos, M. G. E. da Luz

We investigate the quantum control of two qubits interacting with a Markovian environment and evolving as an $X$ state. The control is implemented via a simple applied field, whose profile is determined by means of the piecewise time-independent quantum control method. The goal is to make either the population or the system concurrence to follow a specified tracking control trajectory. By considering the system under the influence of three kinds of noise---phase damping, amplitude damping, or a combination of both---we unveil the conditions (like energy balance) under which the quantum control is properly achieved and fidelity (monitored through the trace distance) is kept satisfactorily high, even if the qubits interact differently with the dissipative medium. We further find that the effects of phase damping, a type of noise which notoriously destroys coherence and entanglement, can be mitigated if during the control the system is also exposed to amplitude damping. Of potential interest for the usage of entanglement as resource for quantum information, our results indicate that distinct entanglement measures and coherence can be maintained relatively high (even at long times) as a consequence of the tracking quantum control process.

Physical Review A•Aug 19, 2022•1 citation
Abstract We investigate the entanglement swapping under phase damping global noise and amplitude damping global noise. The two qubits the intermediate user holds during the entanglement swapping process first suffer from a global noise before the Bell measurement is carried out. Based on this assumption, the influence of global phase damping noise and global amplitude damping noise on the output entanglement of entanglement swapping is investigated, respectively. Our findings imply that the output entanglement is completely independent of the phase damping global noise and determined by the input entanglement when entanglement swapping is performed in a global phase damping noise environment. In addition, when entanglement swapping is executed in an amplitude damping environment, the output entanglement oscillates periodically with time, and the output entanglement may disappear at some points and reappear at others. In this case, we need not only to improve the input entanglement but also to control the evolution time of the amplitude damping global noise to ensure the optimal output entanglement. Our findings may help experimentalists to avoid and utilize environmental noise in entanglement swapping.
Abstract We studied the entangling power of two pure global noises, i.e. amplitude damping noise and classic noise. The entangling power of the two-qubit amplitude damping global noise periodically oscillates with time. Additionally, the entangling power of two-qubit global classical noise increases exponentially with time. The maximum entangling power of both of them exceeds that of the perfect entanglers. Based on this, we propose the conditions for generating a maximally entangled state with global noise acting on a two-qubit separable state. Only if the two-qubit composite system, which is initially in one of those product states: 1 2 ( | 0 ⟩ ± | 1 ⟩ ) ⊗ 1 2 ( | 0 ⟩ ± | 1 ⟩ ) , | 10 ⟩ and | 01 ⟩ suffers an amplitude damping global noise, can we prepare this system in the maximally entangled state by appropriately controlling the evolution time of amplitude damping. Finally, we investigate the disentanglement of the maximum entangled Bell state using these two types of global noise. The two global noises cannot completely disentangle the Bell states Φ ± . Under the influence of amplitude damping global noise, the entanglement of Bell state Ψ + undergoes a cyclical variation, alternating between disappearance and recovery to reach maximum entanglement within one period. The entanglement of either Bell state Ψ + or Ψ − is completely independent of global classical noise. The entanglement of Bell state Ψ − is also robust against amplitude damping global noise.
This paper investigates the degradation mechanism of the photon-number-encoded entanglement swapping protocol under the amplitude damping noise channel. By establishing a beam splitter physical model to simulate the energy dissipation process, the evolution density matrix of the input states [Formula: see text] and [Formula: see text] under independent noise channels is analytically derived, and the density matrix, fidelity, and concurrence of the target particle pair after entanglement swapping are presented. Furthermore, for the case where the initial states are maximally entangled states, this paper numerically simulates the variation curves of the fidelity and concurrence of the system after entanglement swapping with the noise parameter. The results show that as the noise intensity increases, both the fidelity and concurrence of the target system exhibit a decreasing trend. Simultaneously, due to the presence of noise, even if the input states are maximally entangled, the entanglement of the target system after swapping may be destroyed. Based on this, the study further deduces the constraint conditions required to maintain system entanglement in this scenario. Given the restrictive effect of these constraints on entanglement maintenance, this paper also specifically examines the fidelity and concurrence of the target state output from entanglement swapping in the case of 50 : 50 beam splitters when the input states are both maximally entangled. The research finds that in this case, since the constraints are not satisfied, even if the input states are maximally entangled, the entanglement of the output state completely disappears.
We systematically characterize quantum entanglement in all sixteen combinations of two-qubit Bell states across three operational regimes: pure superposition, noiseless mixing, and asymmetric mixing of one noisy and one pure Bell state. For pure superpositions, we calculate the von Neumann entropy and show that entanglement depends critically on the relative phase phi between superposed states. For mixed states, we use concurrence C under three physically motivated decoherence channels. The Depolarizing (DP) and Phase Damping (PD) channels are modeled as global, collective operations on the two-qubit Hilbert space, while Amplitude Damping (AD) is treated as independent local decay on each qubit, reflecting the asymmetric, energy-dissipating nature of spontaneous emission. A central and counterintuitive result is that increasing noise can raise concurrence in specific parameter regimes across all three channels. We further map the boundary between mathematical entanglement (C > 0) and operational quantum non-locality using the Horodecki criterion, finding this boundary to be strongly channel-dependent. Under Phase Damping, the Bell-local entanglement regime vanishes entirely for identical and same-bases mixtures, meaning any surviving entanglement guarantees a CHSH violation. Under Depolarizing noise, a large Bell-local region requires mixing probability r > 1/sqrt(2) to recover non-locality at maximum noise. For Amplitude Damping, certain mixtures exhibit a non-monotonic Horodecki parameter M(T): concurrence decreases monotonically with noise, yet the capacity for CHSH violation is lost at intermediate noise levels and restored at high noise, as maximal damping repurifies the noisy branch. These results provide a unified analytical reference for entanglement and non-locality management across Bell-state combinations and decoherence channels relevant to NISQ architectures.
Abstract We investigate the Bell nonlocality dynamics of bipartite quantum systems under three distinct types of global decoherence environments: global amplitude damping noise, globally correlated classical noise, and global phase-damping noise. By combining numerical optimization techniques over Bell inequalities—specifically the Clauser–Horne–Shimony–Holt inequality—and describing the global noise-evolution process of a two-qubit system with the Kraus operator formalism, we systematically characterize the evolution of quantum nonlocality in a two-qubit system. Our results demonstrate that, under a global amplitude damping noise environment, precise temporal modulation of the amplitude damping channel enables the composite system to retain maximal Bell-nonlocal correlations in its final state. In contrast, globally correlated classical noise fields induce exponential suppression of Bell inequality violations. Remarkably, the systems subjected to global phase-damping noise exhibit pronounced robustness to nonlocality. These findings highlight the critical role of global noise in nonlocality dynamics.
We investigate the quantum control of two qubits interacting with a Markovian environment and evolving as an XXX state. The control is implemented via a simple applied field, whose profile is determined by means of the piecewise time-independent quantum control method. The goal is to make either the population or the system concurrence to follow a specified tracking control trajectory. By considering the system under the influence of three kinds of noise---phase damping, amplitude damping, or a combination of both---we unveil the conditions (like energy balance) under which the quantum control is properly achieved and fidelity (monitored through the trace distance) is kept satisfactorily high, even if the qubits interact differently with the dissipative medium. We further find that the effects of phase damping, a type of noise which notoriously destroys coherence and entanglement, can be mitigated if during the control the system is also exposed to amplitude damping. Of potential interest for the usage of entanglement as resource for quantum information, our results indicate that distinct entanglement measures and coherence can be maintained relatively high (even at long times) as a consequence of the tracking quantum control process.