scholarly journals Teleportation via maximally and non-maximally entangled mixed states

2010 ◽  
Vol 10 (5&6) ◽  
pp. 398-419
Author(s):  
S. Adhikari ◽  
A.S. Majumdar ◽  
S. Roy ◽  
B. Ghosh ◽  
N. Nayak
Keyword(s):  
Mixed State ◽  
Quantum Teleportation ◽  
Convex Combination ◽  
Type Inequality ◽  
Entangled States ◽  
Mixed States ◽  
Werner State ◽  
Parameter Values

We study the efficiency of two-qubit mixed entangled states as resources for quantum teleportation. We first consider two maximally entangled mixed states, viz., the Werner state\cite{werner}, and a class of states introduced by Munro {\it et al.} \cite{munro}. We show that the Werner state when used as teleportation channel, gives rise to better average teleportation fidelity compared to the latter class of states for any finite value of mixedness. We then introduce a non-maximally entangled mixed state obtained as a convex combination of a two-qubit entangled mixed state and a two-qubit separable mixed state. It is shown that such a teleportation channel can outperform another non-maximally entangled channel, viz., the Werner derivative for a certain range of mixedness. Further, there exists a range of parameter values where the former state satisfies a Bell-CHSH type inequality and still performs better as a teleportation channel compared to the Werner derivative even though the latter violates the inequality.

scholarly journals Relevance of rank for a mixed state quantum teleportation resource

2014 ◽  
Vol 14 (13&14) ◽  
pp. 1227-1237
Author(s):  
K.G. Paulson ◽  
S.V.M. Satyanarayana
Keyword(s):  
Lower Bound ◽  
Mixed State ◽  
Upper Bound ◽  
Quantum Teleportation ◽  
Low Rank ◽  
Entangled States ◽  
Mixed States ◽  
Logarithmic Negativity ◽  
Higher Rank ◽  
Fidelity Measures

Mixed entangled states are generic resource for quantum teleportation. Optimal teleportation fidelity measures the success of quantum teleportation. The relevance of rank in the teleportation process is investigated by constructing three new maximally entangled mixed states (MEMS) of different ranks. Linear entropy, concurrence, optimal teleportation fidelity and Bell function are obtained for each of these states analytically. It is found that mixed states with higher rank are better resource for teleportation. In order to achieve a fixed value of optimal teleportation fidelity, we find that low rank states must have high concurrence. Further, for each of ranks 2, 3 and 4, we numerically generate 30000 maximally entangled mixed states. The analysis of these states reveals the existence of a rank dependent upper bound on optimal teleportation fidelity for a fixed purity. In order to achieve a fixed optimal teleportation fidelity, we find MEMS exhibit a rank dependent lower bound on concurrence. MEMS are classified in terms of their degree of nonlocality. The results are found to be same with logarithmic negativity used as a measure of entanglement.

Bipartite entanglement of decohered mixed states generated from maximally entangled cluster states

2021 ◽  
Vol 36 (03) ◽  
pp. 2150010
Author(s):  
Mostafa Mansour ◽  
Saeed Haddadi
Keyword(s):  
Mixed State ◽  
Entangled States ◽  
Entangled State ◽  
Mixed States ◽  
Density Matrices ◽  
Bipartite Entanglement ◽  
Cluster States ◽  
Maximally Entangled State ◽  
Qubit System ◽  
Maximally Entangled States

In this work, we investigate the bipartite entanglement of decohered mixed states generated from maximally entangled cluster states of [Formula: see text] qubits physical system. We introduce the disconnected cluster states for an ensemble of [Formula: see text] non-interacting qubits and we give the corresponding separable density matrices. The maximally entangled states can be generated from disconnected cluster states, by assuming that the dynamics of the multi-qubit system is governed by a quadratic Hamiltonian of Ising type. When exposed to a local noisy interaction with the environment, the multi-qubit system evolves from its initial pure maximally entangled state to a decohered mixed state. The decohered mixed states generated from bipartite, tripartite and multipartite maximally entangled cluster states are explicitly expressed and their bipartite entanglements are investigated.

USEFULNESS CLASSES OF TRAVELING ENTANGLED CHANNELS IN NONINERTIAL FRAMES

2013 ◽  
Vol 27 (28) ◽  
pp. 1350155 ◽  
Author(s):  
N. METWALLY
Keyword(s):  
Pure State ◽  
Quantum Teleportation ◽  
The Self ◽  
Entangled States ◽  
Quantum Channels ◽  
Werner State ◽  
Qubit System ◽  
Pure States

The dynamics of a general two qubit system in a noninetrial frame is investigated analytically, where it is assumed that both of its subsystems are differently accelerated. Two classes of initial traveling states are considered: self-transposed and generic pure states. The entanglement contained in all possible generated entangled states between the qubits and their anti-qubits is quantified. The usefulness of the traveling states as quantum channels to perform quantum teleportation is investigated. For the self-transposed classes, it is shown that the generalized Werner state is the most robust class and starting from a class of pure state, one can generate entangled states more robust than self-transposed classes.

Tripartite Bell-type inequalities for quantum coherence and skew information

2017 ◽  
Vol 15 (04) ◽  
pp. 1750025 ◽  
Author(s):  
Liang Qiu ◽  
Fei Pan ◽  
Zhi Liu
Keyword(s):  
Relative Entropy ◽  
Quantum Coherence ◽  
Type Inequality ◽  
Entangled States ◽  
Mixed States ◽  
Entanglement Witness ◽  
Skew Information ◽  
Relative Entropy Of Coherence

We construct the tripartite Bell-type inequalities of product states for [Formula: see text]-norm of coherence, relative entropy of coherence and skew information. We give examples of three-qubit entangled states that violate these inequalities. Particularly, the tripartite Bell-type inequality for relative entropy of coherence is always violated by the W class pure or mixed states as well as the GHZ class pure or mixed states, being used as entanglement witness.

The treatment of mixed states and the risk of switching to depression

2005 ◽  
Vol 20 (2) ◽  
pp. 96-100 ◽  
Author(s):  
Eduard Vieta
Keyword(s):  
Clinical Trials ◽  
Depressive Symptoms ◽  
Mixed State ◽  
Atypical Antipsychotics ◽  
Randomized Clinical Trials ◽  
Mixed States ◽  
Conventional Antipsychotics

AbstractThere are few controlled studies evaluating the treatment of bipolar mixed states. Evidence suggests that mixed states may be more responsive to some anticonvulsants than to lithium. Olanzapine alone or in combination with divalproate or lithium has been adequately evaluated in randomized clinical trials involving mixed-state patients, whereas risperidone and quetiapine have not. There is also some evidence demonstrating the efficacy of ziprasidone and aripiprazole. The risk of switching to depression is high in mixed states. Conventional antipsychotics, such as haloperidol, may be less efficacious at protecting against a switch to depression than atypical antipsychotics, divalproate or lithium. When choosing drugs for the treatment of mania, and especially for the treatment of mixed states, their efficacy against manic and depressive symptoms, and their safety in terms of the risk of switching to depression should be taken into account.

scholarly journals Probabilistic Resumable Quantum Teleportation of a Two-Qubit Entangled State

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 352 ◽  
Author(s):  
Zhan-Yun Wang ◽  
Yi-Tao Gou ◽  
Jin-Xing Hou ◽  
Li-Ke Cao ◽  
Xiao-Hui Wang
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
The State ◽  
Entangled States ◽  
Entangled State ◽  
Quantum Channels ◽  
Unknown State ◽  
Optimal Probability

We explicitly present a generalized quantum teleportation of a two-qubit entangled state protocol, which uses two pairs of partially entangled particles as quantum channel. We verify that the optimal probability of successful teleportation is determined by the smallest superposition coefficient of these partially entangled particles. However, the two-qubit entangled state to be teleported will be destroyed if teleportation fails. To solve this problem, we show a more sophisticated probabilistic resumable quantum teleportation scheme of a two-qubit entangled state, where the state to be teleported can be recovered by the sender when teleportation fails. Thus the information of the unknown state is retained during the process. Accordingly, we can repeat the teleportion process as many times as one has available quantum channels. Therefore, the quantum channels with weak entanglement can also be used to teleport unknown two-qubit entangled states successfully with a high number of repetitions, and for channels with strong entanglement only a small number of repetitions are required to guarantee successful teleportation.

scholarly journals Virtual Correlations in Single Qutrit

2016 ◽  
Vol 2016 ◽  
pp. 1-5
Author(s):  
Alexey A. Strakhov ◽  
Vladimir I. Man’ko
Keyword(s):  
Mixed State ◽  
Three Dimensional ◽  
Mixed States ◽  
One To One

We construct the positive invertible map of the mixed states of a single qutrit onto the antisymmetrized bipartite qutrit states (quasifermions). It is shown that using this one-to-one correspondence between qutrit states and states of two three-dimensional quasifermions one may attribute hidden entanglement to a single mixed state of qutrit.

Bidirectional quantum teleportation and cyclic quantum teleportation of multi-qubit entangled states via G-state

2020 ◽  
Vol 34 (28) ◽  
pp. 2050261
Author(s):  
Vikram Verma
Keyword(s):  
Quantum Channel ◽  
Quantum Teleportation ◽  
The Other ◽  
Entangled States ◽  
Entangled State ◽  
Bidirectional Quantum Teleportation

We propose a novel scheme for faithful bidirectional quantum teleportation (BQT) in which Alice can transmit an unknown N-qubit entangled state to Bob and at the same time Bob can transmit an unknown M-qubit entangled state to Alice by using a four-qubit entangled G-state as a quantum channel. We also propose a new scheme for cyclic QT of multi-qubit entangled states by using two G-states as a quantum channel. The advantage of our schemes is that it seems to be much simpler and requires reduced number of qubits in quantum channel as compared with the other proposed schemes.

scholarly journals Bounds on Mixed State Entanglement

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 62 ◽  
Author(s):  
Bruno Leggio ◽  
Anna Napoli ◽  
Hiromichi Nakazato ◽  
Antonino Messina
Keyword(s):  
Mixed State ◽  
General Framework ◽  
Quantum Correlations ◽  
Thermal Entanglement ◽  
Mixed States ◽  
Clear Explanation ◽  
Finite Dimensionality ◽  
Partial Transpose ◽  
The Subject

In the general framework of d 1 × d 2 mixed states, we derive an explicit bound for bipartite negative partial transpose (NPT) entanglement based on the mixedness characterization of the physical system. The derived result is very general, being based only on the assumption of finite dimensionality. In addition, it turns out to be of experimental interest since some purity-measuring protocols are known. Exploiting the bound in the particular case of thermal entanglement, a way to connect thermodynamic features to the monogamy of quantum correlations is suggested, and some recent results on the subject are given a physically clear explanation.

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