ENTANGLEMENT DYNAMICS OF TWO QUBITS COUPLED TO SQUEEZED DISSIPATIVE ENVIRONMENTS

2010 ◽  
Vol 24 (26) ◽  
pp. 2635-2645
Author(s):  
CHUAN-JIA SHAN ◽  
TAO CHEN ◽  
JI-BING LIU ◽  
WEI-WEN CHENG ◽  
TANG-KUN LIU ◽  
...  
Keyword(s):  
Steady State ◽  
Sudden Death ◽  
Entangled States ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
Initial Product ◽  
System Parameters ◽  
Initial States ◽  
Dissipative Environments ◽  
Degree Of Entanglement

By analytically solving the Lindblad form of the master equation, we investigate entanglement dynamics of two qubits coupled via the XY interaction, where each qubit is interacting with an independent reservoir with the squeezing parameters and squeezing angles. In the weak-squeezed reservoir, we show that the entanglement sudden death and entanglement sudden birth will happen for various entangled states. Some initial product states evolve into entangled ones, initially entangled states lose completely or partially their entanglement. The effects of varying the degree of entanglement of the initial states, the spin chain system parameters and different values of the degree of squeezing on the sudden death, revival and birth times are analyzed in detail. We also see that the steady state concurrence appears in the squeezed dissipative environments, which is affected by both the system parameters and the degree of squeezing.

Multiatom entanglement dynamics and entanglement transfer between remote cavities via optical fibers

2011 ◽  
Vol 89 (7) ◽  
pp. 753-759 ◽  
Author(s):  
Qi-Liang He ◽  
Ye-Qi Zhang ◽  
Jing-Bo Xu
Keyword(s):  
Sudden Death ◽  
Optical Fibers ◽  
Initial Conditions ◽  
Single Mode ◽  
Entangled State ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
State Transfer ◽  
Perfect Transfer ◽  
Entanglement Transfer

We investigate the entanglement dynamics of a system that consists of four single-mode cavities that are spatially separated and connected by two optical fibers, with multiple two-level atoms trapped in each cavity. It is shown that the phenomenon of entanglement sudden death and sudden birth appears in this system and is sensitive to the initial conditions and the parameter r. In addition, we also study the entanglement and entangled state transfer between the atoms and find that a perfect transfer can be realized if the value of the parameter r satisfies a certain condition, established here.

A STUDY ON THE SUDDEN DEATH AND SUDDEN BIRTH OF ENTANGLEMENT IN AN OPEN SYSTEM

2009 ◽  
Vol 07 (05) ◽  
pp. 949-957 ◽  
Author(s):  
YING-JIE ZHANG ◽  
YUN-JIE XIA
Keyword(s):  
Sudden Death ◽  
Open System ◽  
Entangled State ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
Entanglement Evolution ◽  
Pure Case

In this paper, we consider the entanglement dynamics of two cavities interacting with independent reservoirs. When the cavity entanglement suddenly disappeared, the reservoir entanglement suddenly and necessarily appears. We study the effect of purity of initial entangled state of two cavities on the entanglement evolution, and acquire that the purity of initial entangled state of two cavities can control the apparition time of the entanglement sudden death and the entanglement sudden birth. Also, we find that the conditions on the apparition of the entanglement sudden death and the entanglement sudden birth can be generalized when the initial entangled state of cavities is not pure, which is a complement to the result in the paper [Phys. Rev. Lett.101 (2008) 080503] for the pure case.

scholarly journals INFLUENCE OF DIPOLE-DIPOLE INTERACTION ON DYNAMICS OF ENTANGLED GREENBERGER — HORNE — ZEILINGER STATES FOR TWO QUBITS

2017 ◽  
Vol 19 (9.1) ◽  
pp. 112-121
Author(s):  
E.K. Bashkirov ◽  
T.A. Puzyrnaya
Keyword(s):  
Sudden Death ◽  
Maximum Degree ◽  
Dipole Interaction ◽  
Entanglement Sudden Death ◽  
Ghz States ◽  
Two Photon ◽  
Degree Of Entanglement

The influence of dipole-dipole interaction on dynamics of three- and four-particle GHZ states for two Д-type superconducting flux cubits interacting with one or two different electronic LC cavities via two-photon processes has been investigated. The results show that dipole-dipole interaction does not lead to the disappearance of the effect of entanglement sudden death and does not change the maximum degree of entanglement.

Three-Atom Entanglement Sudden Death and Birth in Cavity QED with the Influence of the Stark Shift

2013 ◽  
Vol 662 ◽  
pp. 537-542 ◽  
Author(s):  
Kun Hua Wu ◽  
Qing Feng Huang ◽  
Xiao Qing Zhang
Keyword(s):  
Sudden Death ◽  
Quantum System ◽  
Cavity Qed ◽  
Stark Shift ◽  
The Other ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics

We investigate the entanglement dynamics in a quantum system consisting of three two-level atoms interacting with three spatially separated cavities with the influence of the Stark shift, and we can find that the entanglement sudden death (ESD) and birth (ESB) will be improved by adjusting the Stark parameters. When we choose the appropriate Stark parameters, the phenomena of ESD and ESB will be appeared, but, which will appear earlier than the other depends on the Stark-shift values.

scholarly journals Asymptotic Entanglement Sudden Death in Two Atoms with Dipole–Dipole and Ising Interactions Coupled to a Radiation Field at Non-Zero Detuning

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 629
Author(s):  
Gehad Sadiek ◽  
Wiam Al-Dress ◽  
Salwa Shaglel ◽  
Hala Elhag
Keyword(s):  
Asymptotic Behavior ◽  
Sudden Death ◽  
Radiation Field ◽  
Quantum Correlation ◽  
Bell State ◽  
Single Mode ◽  
Mean Value ◽  
Entanglement Sudden Death ◽  
Initial State ◽  
System Parameters

We investigate the time evolution and asymptotic behavior of a system of two two-level atoms (qubits) interacting off-resonance with a single mode radiation field. The two atoms are coupled to each other through dipole--dipole as well as Ising interactions. An exact analytic solution for the system dynamics that spans the entire phase space is provided. We focus on initial states that cause the system to evolve to entanglement sudden death (ESD) between the two atoms. We find that combining the Ising and dipole--dipole interactions is very powerful in controlling the entanglement dynamics and ESD compared with either one of them separately. Their effects on eliminating ESD may add up constructively or destructively depending on the type of Ising interaction (Ferromagnetic or anti-Ferromagnetic), the detuning parameter value, and the initial state of the system. The asymptotic behavior of the ESD is found to depend substantially on the initial state of the system, where ESD can be entirely eliminated by tuning the system parameters except in the case of an initial correlated Bell state. Interestingly, the entanglement, atomic population and quantum correlation between the two atoms and the field synchronize and reach asymptotically quasi-steady dynamic states. Each one of them ends up as a continuous irregular oscillation, where the collapse periods vanish, with a limited amplitude and an approximately constant mean value that depend on the initial state and the system parameters choice. This indicates an asymptotic continuous exchange of energy (and strong quantum correlation) between the atoms and the field takes place, accompanied by diminished ESD for these chosen setups of the system. This system can be realized in spin states of quantum dots or Rydberg atoms in optical cavities, and superconducting or hybrid qubits in linear resonators.

Relaxation Due to the Partial Swap Collisions with a Random Reservoir

2011 ◽  
Vol 18 (04) ◽  
pp. 353-362
Author(s):  
Giuseppe Gennaro
Keyword(s):  
Steady State ◽  
Multipartite Entanglement ◽  
Entanglement Dynamics ◽  
Relaxation To Equilibrium ◽  
Initial States ◽  
A Chain ◽  
Random State

We analyze the dynamics of the system consisting of a qubit sequentially interacting with a chain of qubits that are initially individually in a pure random state. Each pairwise collision has been modeled as a partial swap transformation. The relaxation to equilibrium of the purity of the system qubit, averaged over all the initial states of the environment, is analytically computed. In particular, we show that the steady state depends on the parameter η of the partial swap transformation. Finally, we investigate aspects of the entanglement dynamics for qubits and show that such process can create typical multipartite entanglement between the system qubit and the qubits of the chain.

ENTANGLEMENT DYNAMICS MODULATED BY COUPLING STRENGTH IN CAVITY QED

2008 ◽  
Vol 06 (02) ◽  
pp. 341-346 ◽  
Author(s):  
ZHONG-XIAO MAN ◽  
SU FANG ◽  
YUN-JIE XIA
Keyword(s):  
Energy Transfer ◽  
Sudden Death ◽  
Cavity Qed ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
Entanglement Evolution ◽  
Qubit System ◽  
Coupling Strengths ◽  
Entangled Atoms ◽  
Separate Cavities

We study the dynamics of entanglement for a four-qubit system in cavity QED. Two initially entangled atoms A and B are coupled respectively with spatially separate cavities a and b with coupling strengths gA and gB. We show that when gA ≠ gB, the entanglement will oscillate in the period of entanglement sudden death (ESD) for gA = gB, and the oscillation times are related to the ratios between gA and gB. Also, we show that the coupling strengths have the same effects on the entanglement evolution and energy transfer.

ENTANGLEMENT TRAPPING AND SUDDEN DEATH IN A COMMON BAND GAP

2011 ◽  
Vol 09 (06) ◽  
pp. 1533-1541
Author(s):  
FENG HAN ◽  
MING-HUA ZHANG
Keyword(s):  
Sudden Death ◽  
Band Gap ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
Gap Model ◽  
Parameter Region ◽  
Common Band ◽  
The Common ◽  
Atomic Entanglement

Using the pseudomode method, we study the exact entanglement dynamics of two atoms in a common band gap. In order to understand the role played by the common band gap we compare our results with the case of two independent band gap model. We demonstrate that the parameter region at which the entanglement sudden death occurs is smaller than the independent band gap model. Moreover, the atomic entanglement trapping can also be achieved in the common band gap model, and the value of entanglement trapping is larger in the common band gap case than in the independent band gap case.

ATOMIC TUNNELING AND ENTANGLEMENT SUDDEN DEATH IN A DISSIPATIVE ATOM-CAVITY SYSTEM

2009 ◽  
Vol 07 (07) ◽  
pp. 1391-1400
Author(s):  
J. SHEN ◽  
JIAO CHEN ◽  
W. WANG ◽  
X. X. YI
Keyword(s):  
Sudden Death ◽  
Degree Of Freedom ◽  
Entanglement Sudden Death ◽  
Entanglement Dynamics ◽  
External Degree ◽  
Cavity System ◽  
Double Well Potential ◽  
Atom Decay

In this paper, we study the effect of atom decay on the atomic tunneling and entanglement dynamics in an atom-cavity system. This system consists of an atom trapped in a double-well potential and a cavity that couples to the atom. The population of the atom in the left/right well and the dynamics of entanglement are calculated and discussed. We find that the tunneling behaves as a damping-oscillating function of time, and the entanglement between the internal and external degree of freedom of the atom exhibits entanglement sudden death (ESD).

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