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.

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.

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 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.

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.

ENTANGLEMENT EVOLUTION OF A PAIR OF TWO-LEVEL SYSTEMS IN NON-MARKOVIAN ENVIRONMENT

2009 ◽  
Vol 07 (01) ◽  
pp. 385-393 ◽  
Author(s):  
X. L. HUANG ◽  
L. C. WANG ◽  
X. X. YI
Keyword(s):  
Sudden Death ◽  
Time Scale ◽  
Mutual Interaction ◽  
Short Time Scale ◽  
Entanglement Sudden Death ◽  
Initial State ◽  
Entanglement Evolution ◽  
Long Time ◽  
Two Level Systems ◽  
Short Time

The entanglement evolution of a pair of two-level systems is studied in this paper. The two systems without mutual interaction are independently coupled to different two-band non-Markovian environments. By comparing our results to others in the literature, we find that taking one of the Bell states as the initial state, certain non-Markovian effect protects the entanglement in short time scale, while on long time scale it leads to the entanglement sudden death (ESD), which never occurs for this initial state in the Markovian case. Finally, by analyzing the parameters in our model, a relation between disentanglement and decoherence is established and discussed.

scholarly journals TOPOLOGY OF ENTANGLEMENT EVOLUTION OF TWO QUBITS

2012 ◽  
Vol 26 (07) ◽  
pp. 1250054 ◽  
Author(s):  
DONG ZHOU ◽  
GIA-WEI CHERN ◽  
JIANJIA FEI ◽  
ROBERT JOYNT
Keyword(s):  
Sudden Death ◽  
Critical Points ◽  
Polarization Vector ◽  
Entanglement Sudden Death ◽  
Entanglement Evolution ◽  
Separable States ◽  
Qubit System ◽  
Asymptotic Point ◽  
Lower Dimensional

The dynamics of a two-qubit system is considered with the aim of a general categorization of the different ways in which entanglement can disappear in the course of the evolution, e.g., entanglement sudden death. The dynamics is described by the function n(t), where n is the 15-dimensional polarization vector. This representation is particularly useful because the components of n are direct physical observables, there is a meaningful notion of orthogonality, and the concurrence C can be computed for any point in the space. We analyze the topology of the space S of separable states (those having C = 0), and the often lower-dimensional linear dynamical subspace D that is characteristic of a specific physical model. This allows us to give a rigorous characterization of the four possible kinds of entanglement evolution. Which evolution is realized depends on the dimensionality of D and of D∩S, the position of the asymptotic point of the evolution, and whether or not the evolution is "distance-Markovian", a notion we define. We give several examples to illustrate the general principles, and to give a method to compute critical points. We construct a model that shows all four behaviors.

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).

RESEARCH ON THE RELATIONSHIP BETWEEN THE SYMMETRICAL COUPLING AND THE NON-MARKOVIAN RELAXATION CHARACTERISTICS

2012 ◽  
Vol 10 (04) ◽  
pp. 1250043 ◽  
Author(s):  
J. J. HU ◽  
Y. H. JI ◽  
Y. X. YU ◽  
Y. HU
Keyword(s):  
Sudden Death ◽  
Quantum System ◽  
Mixed State ◽  
Entangled State ◽  
Entanglement Sudden Death ◽  
Symmetric State ◽  
Entanglement State ◽  
The Relationship ◽  
Relaxation Characteristics ◽  
Decoherence Free Subspace

We make the study of the relationship between symmetrical coupling of coupling qubits and non-Markovian relaxation characteristics by utilizing concurrence. The results show that the relaxation characteristics of quantum system strongly depend on the coupling way between qubits and environment and the decoherence-free subspace may form under certain conditions. We find that when the system is initially at [Formula: see text] state or the mixed state generated by this state, we can make the quantum system always at the entangled state without entanglement sudden death (ESD) phenomenon by regulating the coupling between qubits and environment at complete anti-symmetric state. In contrast, when the system is initially at [Formula: see text] state or the mixed state generated by this state, then we must regulate the coupling way between qubits and environment at complete symmetric state to make the quantum system maintain at the entanglement state.

Sign in / Sign up

Export Citation Format

Share Document