LONG-LIVED ENTANGLEMENT OF THREE-ATOM IN AN OPTICAL CAVITY WITH PHASE DECOHERENCE

2010 ◽  
Vol 24 (09) ◽  
pp. 897-904
Author(s):  
JIAN-SONG ZHANG ◽  
AI-XI CHEN

We investigate the entanglement dynamics in a quantum system consisting of three two-level atoms resonantly coupled to a single mode cavity in the presence of phase decoherence. With the help of the dynamical algebraic method, we obtain an analytical solution of the present system. The influence of phase decoherence on the entanglement of the system is studied. We find that the entanglement between the cavity field and any atom will be destroyed completely by phase decoherence as the system evolves. However, there is long-lived entanglement (or stationary state entanglement) of arbitrary two atoms, that is, the entanglement of atoms is more robust against phase decoherence than that of the atom-field system.

2008 ◽  
Vol 22 (26) ◽  
pp. 2587-2599 ◽  
Author(s):  
N. H. ABDEL-WAHAB

In this article, the problem of a double Ξ-type four-level atom interacting with a single-mode cavity field is considered. The considered model describes several distinct configurations of a four-level atom. Also, this model includes the detuning parameters of the atom-field system. We obtain the constants of motion and the wavefunction is derived when the atom is initially prepared in the upper state. We used this model for computing a number of the field aspects for the considered system. As an illustration, the model is used for studying the time evolution of the Mandel Q-parameter, amplitude-squared squeezing phenomenon and Q-function when the input field is considered in a coherent state. The results show that these phenomena are affected by the presence of detuning parameters.


2009 ◽  
Vol 07 (05) ◽  
pp. 1001-1007 ◽  
Author(s):  
JIAN-SONG ZHANG ◽  
AI-XI CHEN

We investigate the entanglement dynamics in a quantum system consisting of three two-level atoms resonantly coupled to a single mode electromagnetic field in a cavity. An explicit analytical solution of the system is obtained and the entanglement of the system is studied with the help of the concurrence and tangle. It is also shown that the W states could be generated if the interaction time of the two-level atoms and the cavity field is chosen appropriately.


2009 ◽  
Vol 07 (07) ◽  
pp. 1337-1348
Author(s):  
FENG HAN ◽  
YUN-JIE XIA

The pairwise entanglement dynamics in a multipartite system consisting of three two-level atoms A, B, C and a single-mode cavity field a is studied via negativity. Three atoms are arranged in such a way that atoms BC are embedded in and locally interact with the cavity while atom A is located in a spatially separate place outside of the cavity. Initially, atom-pair AB is prepared in a Bell-like state while atom C in a superposition of ground and excited state, |gC〉 and |eC〉. It shall be shown that all the pairwise negativities of the total system including atoms and cavity undergo qualitatively different evolutions. The so-called entanglement sudden death is observed for atom-pair AB under certain conditions and the entanglement transfer among all the possible degrees of freedom of the whole system is also discussed.


2015 ◽  
Vol 29 (29) ◽  
pp. 1550175 ◽  
Author(s):  
N. H. Abd El-Wahab ◽  
Ahmed Salah

We study the interaction between a single mode electromagnetic field and a three-level [Formula: see text]-type atom in the presence of a classical homogenous gravitational field when the atom is prepared initially in the momentum eigenstate. The model includes the detuning parameters and the classical homogenous gravitational field. The wave function is calculated by using the Schrödinger equation for a coherent electromagnetic field and an atom is in its excited state. The influence of the detuning parameter and the classical homogenous gravitational field on the temporal behavior of the mean photon number, the normalized second-order correlation function and the normal squeezing is analyzed. The results show that the presence of these parameters has an important effect on these phenomena. The conclusion is reached and some features are given.


2008 ◽  
Vol 22 (08) ◽  
pp. 561-568 ◽  
Author(s):  
JIAN-SONG ZHANG ◽  
JING-BO XU

We investigate the entanglement of two two-mode two-photon Jaynes–Cummings models in the presence of phase decoherence. We find an explicit analytical solution of the system and discuss the influence of the phase decoherenc on the entanglement dynamics. Our results shows that the entanglement of the two initially entangled atoms can remain zero for a finite time and revive later. However, if the phase decoherence is taken into accounted, the entanglement cannot revive completely.


2017 ◽  
Vol 15 (08) ◽  
pp. 1740012
Author(s):  
V. I. Koroli ◽  
S. Palistrant ◽  
A. Nistreanu

We study the two-photon interaction between a three-level equidistant radiator (atom, molecule) with different dipole transitions and the single-mode cavity field. It is supposed that the three-level radiator is laser cooled and trapped into the ground vibrational state, in which the vibrational quantum number [Formula: see text]. In the proposed two-photon Jaynes–Cummings model (JCM) of a three-level atom at the initial moment [Formula: see text], the quantized cavity field is prepared in the squeezed vacuum state and the three-level radiator in the first excited state [Formula: see text]. By using the exact analytical solution for the state-vector of the coupled atom-field system, the amplitude-squared squeezing of the quantized cavity field is examined as a function of the [Formula: see text] and [Formula: see text] parameters. In this situation, higher-order squeezing has the tendency towards oscillations, but the exact periodicity of these oscillations is violated by the analogy with the second-order squeezing.


2003 ◽  
Vol 17 (14) ◽  
pp. 2699-2713 ◽  
Author(s):  
Meng Zhang ◽  
Jian Zou ◽  
Bin Shao

We consider a single-Cooper-pair box biased by a classical voltage and also irradiated by a single-mode quantized field. We assume that the box is initially in a mixed state, and investigate the quantum dynamics of the Cooper-pair box and show that the collapse and revival phenomenon can exist in this system. We also study the quantum entropy of the single-Cooper-pair box and discuss the effects of the different parameters on this quantum entropy. We find that the box, which is initially in a mixed state, may evolve into an almost pure state.


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