scholarly journals Entanglement Robustness via Spatial Deformation of Identical Particle Wave Functions

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 708
Author(s):  
Matteo Piccolini ◽  
Farzam Nosrati ◽  
Giuseppe Compagno ◽  
Patrizia Livreri ◽  
Roberto Morandotti ◽  
...  
Keyword(s):  
Identical Particle ◽  
Quantum Correlations ◽  
Wave Functions ◽  
Noisy Environments ◽  
Classical Communication ◽  
Entanglement Protection ◽  
Phase Damping ◽  
Spatial Deformation ◽  
Amplitude Damping Channel ◽  
Depolarizing Channel

We address the problem of entanglement protection against surrounding noise by a procedure suitably exploiting spatial indistinguishability of identical subsystems. To this purpose, we take two initially separated and entangled identical qubits interacting with two independent noisy environments. Three typical models of environments are considered: amplitude damping channel, phase damping channel and depolarizing channel. After the interaction, we deform the wave functions of the two qubits to make them spatially overlap before performing spatially localized operations and classical communication (sLOCC) and eventually computing the entanglement of the resulting state. This way, we show that spatial indistinguishability of identical qubits can be utilized within the sLOCC operational framework to partially recover the quantum correlations spoiled by the environment. A general behavior emerges: the higher the spatial indistinguishability achieved via deformation, the larger the amount of recovered entanglement.

scholarly journals Analysis of Decoherence in Linear and Cyclic Quantum Walks

Optics ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 236-250
Author(s):  
Mahesh N. Jayakody ◽  
Asiri Nanayakkara ◽  
Eliahu Cohen
Keyword(s):  
Probability Distributions ◽  
Quantum Walks ◽  
Noisy Environments ◽  
Data Encoding ◽  
Phase Damping ◽  
Initial States ◽  
Binomial Transform ◽  
Bit Flip ◽  
Depolarizing Channel ◽  
Cyclic Path

We theoretically analyze the case of noisy Quantum walks (QWs) by introducing four qubit decoherence models into the coin degree of freedom of linear and cyclic QWs. These models include flipping channels (bit flip, phase flip and bit-phase flip), depolarizing channel, phase damping channel and generalized amplitude damping channel. Explicit expressions for the probability distribution of QWs on a line and on a cyclic path are derived under localized and delocalized initial states. We show that QWs which begin from a delocalized state generate mixture probability distributions, which could give rise to useful algorithmic applications related to data encoding schemes. Specifically, we show how the combination of delocalzed initial states and decoherence can be used for computing the binomial transform of a given set of numbers. However, the sensitivity of QWs to noisy environments may negatively affect various other applications based on QWs.

Fisher and skew information for two-qubit Bell states under decoherence effects

2020 ◽  
Vol 18 (04) ◽  
pp. 2050018
Author(s):  
R. Laghmach ◽  
H. El Hadfi ◽  
B. Maroufi ◽  
M. Daoud
Keyword(s):  
Fisher Information ◽  
Dynamical Behavior ◽  
Quantum Fisher Information ◽  
Bell States ◽  
Thermal Entanglement ◽  
Noisy Channels ◽  
Phase Damping ◽  
Skew Information ◽  
Amplitude Damping Channel ◽  
Depolarizing Channel

We give the explicit expressions of quantum Fisher information and skew information for a two-qubit Bell states. We investigate their dynamics under the decoherence effects: phase-damping channel, depolarizing channel and amplitude-damping channel. We also discuss the thermal entanglement quantified by Wootters concurrence for these three decoherence channels and we compare its dynamical behavior with the quantum Fisher information and skew information. We then use this comparison to investigate the influence of noisy channels on thermal entanglement and its role in boosting the performance of metrology protocols. It is shown that the correlations in two-qubit Bell states are more resistant to phase-damping channel and depolarizing channels.

scholarly journals MINIMAL ENTANGLEMENT FIDELITIES OF SOME SINGLE QUBIT QUANTUM NOISY CHANNELS

2002 ◽  
Vol 16 (01n02) ◽  
pp. 19-25 ◽  
Author(s):  
XIAN-TING LIANG
Keyword(s):  
The Other ◽  
Noisy Channels ◽  
Amplitude Damping ◽  
Single Qubit ◽  
Phase Damping ◽  
Amplitude Damping Channel ◽  
Depolarizing Channel ◽  
Quantum Noisy Channels

The minimal entanglement fidelities of the phase damping channel, depolarizing channel, two-Pauli channel and amplitude damping channel are calculated. It is shown that for the same condition, the minimal fidelity of the phase damping channel is the biggest among the four channels. The minimal fidelity of the depolarizing channel is bigger than the other two.

scholarly journals Entanglement of Open Quantum Systems in Noninertial Frames

2012 ◽  
Vol 19 (02) ◽  
pp. 1250013 ◽  
Author(s):  
S. Khan ◽  
M. K. Khan
Keyword(s):  
Sudden Death ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Unruh Effect ◽  
Entanglement Sudden Death ◽  
Phase Damping ◽  
Amplitude Damping Channel ◽  
Stationary Frame ◽  
Depolarizing Channel ◽  
Accelerated Frames

We study the effects of decoherence on the entanglement generated by Unruh effect in accelerated frames by using various combinations of an amplitude damping channel, a phase damping channel and a depolarizing channel in the form of multilocal and collective environments. Using concurrence as entanglement quantifier, we show that the occurrence of entanglement sudden death (ESD) depends on different combinations of the channels. The ESD can be avoided under a particular configuration of the channels. We show that the channels can be used to distinguish between a moving and a stationary frame.

Witnessing pairing correlations in identical-particle systems

2021 ◽  
Vol 21 (15&16) ◽  
pp. 1307-1319
Author(s):  
Cagan Aksak ◽  
Sadi Turgut
Keyword(s):  
Annihilation Operator ◽  
Identical Particle ◽  
Quantum Correlations ◽  
Particle Systems ◽  
Fermionic Systems ◽  
Different Types ◽  
Pairing Correlations

Quantum correlations and entanglement in identical-particle systems have been a puzzling question which has attracted vast interest and widely different approaches. Witness formalism developed first for entanglement measurement can be adopted to other kind of correlations. An approach is introduced by Kraus \emph{et al.}, [Phys. Rev. A \textbf{79}, 012306 (2009)] based on pairing correlations in fermionic systems and the use of witness formalism to detect pairing. In this contribution, a two-particle-annihilation operator is used for constructing a two-particle observable as a candidate witness for pairing correlations of both fermionic and bosonic systems. The corresponding separability bounds are also obtained. Two different types of separability definition are introduced for bosonic systems and the separability bounds associated with each type are discussed.

scholarly journals Quantum Correlation via Skew Information and Bell Function Beyond Entanglement in a Two-Qubit Heisenberg XYZ Model: Effect of the Phase Damping

2020 ◽  
Vol 10 (11) ◽  
pp. 3782 ◽  
Author(s):  
Abdel-Baset A. Mohamed ◽  
Ahmed Farouk ◽  
Mansour F. Yassen ◽  
Hichem Eleuch
Keyword(s):  
Sudden Change ◽  
Quantum Correlations ◽  
Physical Parameters ◽  
Phase Damping ◽  
Change Behavior ◽  
Skew Information ◽  
Local Correlations ◽  
Non Local ◽  
Moriya Interaction ◽  
Non Locality

In this paper, we analyze the dynamics of non-local correlations (NLCs) in an anisotropic two-qubit Heisenberg XYZ model under the effect of the phase damping. An analytical solution is obtained by applying a method based on the eigenstates and the eigenvalues of the Hamiltonian. It is observed that the generated NLCs are controlled by the Dzyaloshinskii–Moriya interaction, the purity indicator, the interaction with the environment, and the anisotropy. Furthermore, it is found that the quantum correlations, as well as the sudden death and sudden birth phenomena, depend on the considered physical parameters. In particular, the system presents a special correlation: the skew-information correlation. The log-negativity and the uncertainty-induced non-locality exhibit the sudden-change behavior. The purity of the initial states plays a crucial role on the generated nonlocal correlations. These correlations are sensitive to the DM interaction, anisotropy, and phase damping.

ENTANGLEMENT-ASSISTED CLASSICAL CAPACITIES OF SOME SINGLE QUBIT QUANTUM NOISY CHANNELS

2002 ◽  
Vol 16 (12) ◽  
pp. 441-448 ◽  
Author(s):  
XIAN-TING LIANG ◽  
HONG-YI FAN
Keyword(s):  
Noisy Channels ◽  
Single Qubit ◽  
Phase Damping ◽  
Analytical Results ◽  
Bit Flip ◽  
Depolarizing Channel ◽  
Quantum Noisy Channels

In this paper, we calculate the entanglement-assisted classical capacities of the depolarizing channel, the phase damping channel, the phase flip channel, the bit flip channel, the bit-phase flip channel, the two-Pauli channel and the amplitude channel, and discuss the analytical results obtained. The Stokes papametrization representation of a qubit and the characteristic of unitary covariance of some quantum noisy channels are used in the calculations.

scholarly journals Quantum entanglement and classical communication through a depolarizing channel

2000 ◽  
Vol 47 (2-3) ◽  
pp. 325-331 ◽  
Author(s):  
Dagmar Bruss ◽  
Lara Faoro ◽  
Chiara Macchiavello ◽  
G. Massimo Palma
Keyword(s):  
Quantum Entanglement ◽  
Classical Communication ◽  
Depolarizing Channel

scholarly journals Local available quantum correlations for Bell Diagonal states and Markovian decoherence

2018 ◽  
Vol 64 (6) ◽  
pp. 662
Author(s):  
Hermann L Albrecht Q ◽  
Douglas F. Mundarain ◽  
Mario I. Caicedo S.
Keyword(s):  
Sudden Death ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
Entanglement Sudden Death ◽  
Dissipative Dynamics ◽  
Phase Damping ◽  
Werner States ◽  
Kraus Operators

Local available quantum correlations (LAQCs), as dened by Mundarain et al. [19], are analytically determined for Bell Diagonal states. Using the Kraus operators formalism [10], we analyze the dissipative dynamics of 2-qubit LAQCs under Markovian decoherence. This is done for Werner states under the depolarizing [20] and phase damping channels [21]. Since Werner states are among those that exhibit the so called entanglement sudden death [27], the results are compared with the ones obtained for Quantum Discord [22], as analyzed by Werlang et al. [24], as well as for entanglement, i.e. Concurrence[7]. The LAQCs quantier, as Quantum Discord does, only vanishes asymptotically.

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