SCHEME FOR THE PREPARATION OF ENTANGLEMENT OF ATOMIC ENSEMBLES

2009 ◽  
Vol 07 (08) ◽  
pp. 1459-1467 ◽  
Author(s):  
LIN-LIN XU ◽  
YA-FEI YU ◽  
ZHI-MING ZHANG
Keyword(s):  
Atomic System ◽  
Vacuum State ◽  
Classical Field ◽  
Ghz State ◽  
W State ◽  
Evolution Process ◽  
Entangled States ◽  
Atomic Ensemble ◽  
Atomic Ensembles ◽  
Cavity Decay

In this paper, we present a scheme to prepare the W state and the GHZ state of many atomic ensembles based on the dynamics of the atomic system of a single control atom and an atomic ensemble dispersively coupling with a cavity, where the control atom is illuminated by a highly detuned auxiliary classical field at the same time. The dynamics of the atomic system can be described by an effective Jaynes–Cummings model (JCM) with the atomic ensemble as the bosonic mode. The preparation of the entangled states is deterministic. Because the cavity is always in the vacuum state during the whole evolution process, our scheme is less sensitive to the cavity decay.

Dynamics of multi-qubit states in non-inertial frames for quantum communication applications

2014 ◽  
Vol 14 (3&4) ◽  
pp. 255-264
Author(s):  
Alaa Sagheer ◽  
Hala Hamdoun
Keyword(s):  
Degradation Rate ◽  
Quantum Communication ◽  
Ghz State ◽  
The Other ◽  
W State ◽  
Entangled States ◽  
Inertial Frames ◽  
Qubit States ◽  
Degree Of Entanglement ◽  
Accelerated Frames

In this paper, some properties of multi-qubit states traveling in non-inertial frames are investigated, where we assume that all particles are accelerated. These properties are including fidelities, capacities and entanglement of the accelerated channels for three different states, namely, Greeberger-Horne-Zeilinger (GHZ) state, GHZ-like state and W-state. It is shown here that all these properties are decreased as the accelerations of the moving particles are increased. The obtained results show that the GHZ-state is the most robust state comparing to the others, where the degradation rate is less than that for the other states particularly in the second Rindler region. Also, it is shown here that the entangled property doesn't change in the accelerated frames. Additionally, the paper shows that the degree of entanglement decreases as the accelerations of the particles increase in the first Rindler region. However in the second region, where all subsystems are disconnected at zero acceleration, entangled states are generated as the acceleration increases.

Generation of W state and GHZ state of multiple atomic ensembles via a single atom in a nonresonant cavity

2014 ◽  
Vol 312 ◽  
pp. 269-274 ◽  
Author(s):  
Chun-Ling Zhang ◽  
Wen-Zhang Li ◽  
Mei-Feng Chen
Keyword(s):  
Ghz State ◽  
W State ◽  
Single Atom ◽  
Atomic Ensembles

scholarly journals Entangling three qubits without ever touching

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pawel Blasiak ◽  
Marcin Markiewicz
Keyword(s):  
Ghz State ◽  
W State ◽  
Entangled States ◽  
Identical Particles ◽  
Practical Applications ◽  
Linear Optical ◽  
Anyon Statistics

AbstractAll identical particles are inherently correlated from the outset, regardless of how far apart their creation took place. In this paper, this fact is used for extraction of entanglement from independent particles unaffected by any interactions. Specifically, we are concerned with operational schemes for generation of all tripartite entangled states, essentially the GHZ state and the W state, which prevent the particles from touching one another over the entire evolution. The protocols discussed in the paper require only three particles in linear optical setups with equal efficiency for boson, fermion or anyon statistics. Within this framework indistinguishability of particles presents itself as a useful resource of entanglement accessible for practical applications.

EFFICIENT TELEPORTATION OF UNKNOWN ATOMIC ENTANGLED STATES

2006 ◽  
Vol 04 (04) ◽  
pp. 627-631 ◽  
Author(s):  
YAN ZHAO ◽  
MING YANG ◽  
ZHUO-LIANG CAO
Keyword(s):  
Cavity Qed ◽  
Thermal Field ◽  
Photon Number ◽  
Success Probability ◽  
Bell State ◽  
Classical Field ◽  
Entangled States ◽  
Effective Hamiltonian ◽  
State Measurement ◽  
Cavity Decay

We propose a scheme for teleporting unknown atomic entangled states in cavity QED. With the assistance of a strong classical field, the photon number dependent parts in the effective Hamiltonian are canceled. Thus, the scheme is insensitive to both the cavity decay and the thermal field. In addition, our scheme does not require the Bell-state measurement directly and the success probability can reach 1.0 in our scheme.

Entanglement criteria for the three-qubit states

2017 ◽  
Vol 15 (07) ◽  
pp. 1750049 ◽  
Author(s):  
Y. Akbari-Kourbolagh
Keyword(s):  
White Noise ◽  
Tensor Products ◽  
W State ◽  
Entangled States ◽  
Mean Values ◽  
W States ◽  
Pauli Matrices ◽  
The Mean ◽  
Simple Sets ◽  
Qubit States

We present sufficient criteria for the entanglement of three-qubit states. For some special families of states, the criteria are also necessary for the entanglement. They are formulated as simple sets of inequalities for the mean values of certain observables defined as tensor products of Pauli matrices. The criteria are good indicators of the entanglement in the vicinity of three-qubit GHZ and W states and enjoy the capability of detecting the entangled states with positive partial transpositions. Furthermore, they improve the best known result for the case of W state mixed with the white noise. The efficiency of the criteria is illustrated through several examples.

scholarly journals Optimal collection of radiation emitted by a trapped atomic ensemble

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Árpád Kurkó ◽  
Peter Domokos ◽  
András Vukics ◽  
Thomas Bækkegaard ◽  
Nikolaj Thomas Zinner ◽  
...  
Keyword(s):  
Quantum Information ◽  
Density Distribution ◽  
Ground State ◽  
Cold Atoms ◽  
Information Storage ◽  
Atomic Ensemble ◽  
Normal Density ◽  
Atomic Ensembles ◽  
Optical Photons ◽  
Electronic Ground

AbstractTrapped atomic ensembles are convenient systems for quantum information storage in the long-lived sublevels of the electronic ground state and its conversion to propagating optical photons via stimulated Raman processes. Here we investigate a phase-matched emission of photons from a coherently prepared atomic ensemble. We consider an ensemble of cold atoms in an elongated harmonic trap with normal density distribution, and determine the parameters of paraxial optics to match the mode geometry of the emitted radiation and optimally collect it into an optical waveguide.

The computational power of the W and GHZ states

2006 ◽  
Vol 6 (2) ◽  
pp. 173-183
Author(s):  
E. D'Hondt ◽  
P. Panangaden
Keyword(s):  
Pure State ◽  
Lie Symmetry ◽  
Leader Election ◽  
Ghz State ◽  
W State ◽  
Computational Power ◽  
Post Processing ◽  
Distributed Consensus ◽  
Quantum Networks ◽  
Impossibility Results

It is well understood that the use of quantum entanglement significantly enhances the computational power of systems. Much of the attention has focused on Bell states and their multipartite generalizations. However, in the multipartite case it is known that there are several inequivalent classes of states, such as those represented by the W-state and the GHZ-state. Our main contribution is a demonstration of the special computational power of these states in the context of paradigmatic problems from classical distributed computing. Concretely, we show that the W-state is the only pure state that can be used to exactly solve the problem of leader election in anonymous quantum networks. Similarly we show that the GHZ-state is the only one that can be used to solve the problem of distributed consensus when no classical post-processing is considered. These results generalize to a family of W- and GHZ-like states. At the heart of the proofs of these impossibility results lie symmetry arguments.

scholarly journals MAXIMALLY ENTANGLED STATES AND BELL'S INEQUALITY IN RELATIVISTIC REGIME

2009 ◽  
Vol 07 (01) ◽  
pp. 395-401 ◽  
Author(s):  
SHAHPOOR MORADI
Keyword(s):  
Ghz State ◽  
Entangled States ◽  
Entangled State ◽  
Maximally Entangled State ◽  
Expectation Value ◽  
Spin Observables ◽  
Chsh Inequality ◽  
Relativistic Regime ◽  
Maximal Violation ◽  
Maximally Entangled States

In this letter we show that in the relativistic regime, maximally entangled state of two spin-1/2 particles not only gives maximal violation of the Bell-CHSH inequality but also gives the largest violation attainable for any pairs of four spin observables that are noncommuting for both systems. Also, we extend our results to three spin-1/2 particles. We obtain the largest eigenvalue of Bell operator and show that this value is equal to the expectation value of Bell operator on GHZ state.

Preparation of Arbitrary Four-Qubit W State with Atomic Ensembles via Rydberg Blockade

2010 ◽  
Vol 27 (4) ◽  
pp. 040307 ◽  
Author(s):  
Han Yang ◽  
Wu Chun-Wang ◽  
Gao Ming ◽  
Liang Lin-Mei ◽  
Chen Ping-Xing ◽  
...  
Keyword(s):  
W State ◽  
Atomic Ensembles ◽  
Rydberg Blockade

MULTIPLE CONCURRENCE OF MULTI-PARTITE QUANTUM SYSTEM

2010 ◽  
Vol 08 (07) ◽  
pp. 1169-1177 ◽  
Author(s):  
HUA WU ◽  
XIN ZHAO ◽  
YAN-SONG LI ◽  
GUI-LU LONG
Keyword(s):  
Quantum System ◽  
Pure State ◽  
Arbitrary Number ◽  
Cluster State ◽  
Ghz State ◽  
W State ◽  
Entanglement Property ◽  
Analytical Results ◽  
Global Entanglement ◽  
Number Of Particles

We propose a new way of description of the global entanglement property of a multi-partite pure state quantum system. Based on the idea of bipartite concurrence, by dividing the multi-partite quantum system into two subsystems, a combination of all the bipartite concurrences of a multi-partite quantum system is used to describe the entanglement property of the multi-partite system. We derive the analytical results for GHZ-state, W-state with arbitrary number of qubits, and cluster state with the number of particles no greater than 6.

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