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Sudden death and revival qubits coupled collectively of entanglement of two to a thermal reservoir 下载免费PDF全文
In this paper, we investigate the entanglement of two qubits coupled collectively to a common thermal environment and find that the the collective decay can lead to a revival of the entanglement that has already been destroyed. We also show that the ability of the system to revival entanglement relies on the mean photon number of the thermal environment and the degree of entanglement of the initial state. 相似文献
3.
Sudden death and revival of entanglement of two qubits coupled collectively to a thermal reservoir 下载免费PDF全文
In this paper, we investigate the entanglement of two qubits coupled collectively to a common thermal environment and find that the the collective decay can lead to a revival of the entanglement that has already been destroyed. We also show that the ability of the system to revival entanglement relies on the mean photon number of the thermal environment and the degree of entanglement of the initial state. 相似文献
4.
Entanglement sudden death of two atoms interacting with a cavity via the two-photon process in a strong-driving-assisted system 下载免费PDF全文
We examine the entanglement dynamics between two strongly
driven atoms off-resonantly coupled with a single-mode cavity via
the two-photon process with the help of negativity in two different
types of initial states. The results show that entanglement sudden
death may occur under both the above conditions and the sudden death
effect can be monitored by modulating the atom--cavity detunings.
Furthermore, we also find an atomic decoherence-free subspace so
that the initial entanglement between two atoms remains invariable
in application. 相似文献
5.
In this paper the so-called sudden death effect of entanglement is
investigated in a quantum model. The results show that one can
expect the resurrection of the original entanglement to occur in a
periodic way following each sudden death event. The length of the
time interval for the zero entanglement depends not only on the
degree of entanglement of the initial state but also on the initial
state. 相似文献
6.
研究了两个初始处于纠缠相干态上的宏观场各自独立地与一个环境相互作用的系统, 环境对腔场的影响只体现在腔场光子数的泄漏上. 采用共生纠缠(concurrence)度量两个宏观场间的纠缠, 并给出宏观场纠缠的解析解, 以分析这种系统中宏观场纠缠的动力学特性. 研究表明当场的初始平均光子数较大时, 即使很小的光子泄漏率也会导致腔场间出现纠缠突然死亡现象. 同时研究结果也表明光子从腔场泄漏到环境后会导致两环境间的纠缠突然产生, 而这种纠缠产生的时机直接与腔场的初始光子数相关. 本文还进一步发现在大光子数的情况下, 在任何时刻任意一个腔场与任意一个环境间都不会产生纠缠.
关键词:
纠缠相干态
环境
纠缠突然死亡
纠缠突然产生 相似文献
7.
The influences of dipole--dipole interaction and detuning on the sudden death of entanglement between two atoms in the Tavis--Cummings model 下载免费PDF全文
The influences of dipole--dipole interaction and detuning on the
entanglement between two atoms with different initial tripartite
entangled W-like states in the Tavis--Cummings model have been
investigated by means of Wootters' concurrence, respectively. The
results show that the entanglement between the two atoms can be
enhanced via appropriately tuning the strength of dipole--dipole
interaction of two atoms or the detunings between atom and cavity,
and the so-called sudden death effect can be weakened
simultaneously. 相似文献
8.
The entanglement of two moving atoms interacting with a single-mode field via a three-photon process 下载免费PDF全文
In this paper, the entanglement of two moving atoms
induced by a single-mode field via a three-photon process is
investigated. It is shown that the entanglement is dependent on the
category of the field, the average photon number N, the number p
of half-wave lengths of the field mode and the atomic initial state.
Also, the sudden death and the sudden birth of the entanglement are
detected in this model and the results show that the existence of the
sudden death and the sudden birth depends on the parameter and the
category of the mode field. In addition, the three-photon process is a higher
order nonlinear process. 相似文献
9.
The entanglement of two dipole--dipole coupled atoms interacting with a thermal field via a two-photon process 下载免费PDF全文
This paper studies entanglement between two dipole-dipole coupled atoms interacting with a thermal field via a two-photon process. It shows that the entanglement is dependent on the mean photon number of the thermal field and the dipole-dipole interaction. The results also show that the atom-atom entanglement through the two-photon process is larger than that through the one-photon process and a remarkable amount of entanglement between the atoms still remains at certain times even for a very highly noisy thermal field. 相似文献
10.
We study the dynamics of entanglement of two initially separate atoms passing through a cavity one after another by employing the concurrence and negativity. The effects of the atomic coherence and mean photon number on the time evolution of atom-atom entanglement are examined when the field is initially in thermal field. We show that the phenomenon of sudden birth of entanglement occurs in some certain conditions and the threshold time for the creation of the entanglement can be controlled by the atomic coherence and mean photon number of the field. It is also shown that the entanglement between two atoms can be created even if the two atoms are initially in excited states. 相似文献
11.
Sudden birth versus sudden death of entanglement for the extended Werner-like state in a dissipative environment 下载免费PDF全文
In this paper, we investigate the dynamical behaviour of
entanglement in terms of concurrence in a bipartite system
subjected to an external magnetic field under the action of
dissipative environments in the extended Werner-like initial state.
The interesting phenomenon of entanglement sudden death as well as
sudden birth appears during the evolution process. We analyse in
detail the effect of the purity of the initial entangled state of two qubits
via Heisenberg XY interaction on the apparition time of entanglement
sudden death and entanglement sudden birth. Furthermore, the
conditions on the conversion of entanglement sudden death and
entanglement sudden birth can be generalized when the initial
entangled state is not pure. In particular, a critical purity of the
initial mixed entangled state exists, above which entanglement
sudden birth vanishes while entanglement sudden death appears. It is
also noticed that stable entanglement, which is independent of
different initial states of the qubits (pure or mixed state), occurs
even in the presence of decoherence. These results arising from the
combination of the extended Werner-like initial state and dissipative
environments suggest an approach to control and enhance the
entanglement even after purity induced sudden birth, death and
revival. 相似文献
12.
This paper studies the entanglement properties in a system of two dipole-dipole coupled two-level atoms resonantly interacting with a single-mode thermal field. The results show that, when the temperature of the cavity is high enough (corresponding to the large value of the mean photon number), the entanglement is greatly enhanced due to the initial atomic coherence. These results are helpful for controlling the atomic entanglement by changing the initial parameters of the system. 相似文献
13.
Extending the double Jaynes--Cummings model to a more
complicated case where the mode--mode competition is considered, we
investigate the entanglement character of two isolated atoms by
means of concurrence, and discuss the dependence of atom--atom
entanglement on the different initial state and the relative
coupling strength between the atom and the corresponding cavity
field. The results show that the amplitude and the period of the
atom--atom entanglement evolution can be controlled by the choice of
initial state and relative coupling strength, respectively. We find
that the phenomenon of entanglement sudden death (ESD) is sensitive
to the initial conditions. The length of the time interval for
zero entanglement depends not only on the initial degree of
entanglement between two atoms but also on the relative coupling
strength of atom--field interaction. The ESD effect can be weakened
by enhancing the mode--mode competition between the three- and
single-photon processes. 相似文献
14.
This paper investigates the periodic death and anabiosis of the entanglement between two moving atoms interacting with the mode field, and discusses the influences of the atomic motion and the parameter of the mode field. The results show that, the atomic motion leads to the periodic death and anabiosis of the entanglement between two moving atoms, the time of the death and the amplitude of the anabiosis of the entanglement between two moving atoms depend on the initial states of two moving atoms and the parameter of the mode field. 相似文献
15.
This paper proposes an efficient scheme for quantum
communication between two atoms trapped in distant cavities which
are connected by an optical fibre. During the operation, all the atomic system,
the cavity modes and the fibre are not excited. The quantum state
is mediated by the vacuum fields. The idea can be used to realize
quantum entanglement between two distant atoms via vacuum. 相似文献
16.
We investigate the entanglement dynamics of a system composed of two non-interacting qubits, A and B. A third qubit, C, only has the Dzyaloshinskii-Moriya (DM) spin-orbit interaction with qubit B. We find that the DM interaction can induce the entanglement sudden death (ESD) of the system qubits A and B, and properly mixing the initial state of the system and adjusting the state of qubit C are two effective methods of controlling ESD. 相似文献
17.
We investigate the entanglement dynamics of a system composed of two non-interacting qubits,A and B.A third qubit,C,only has the Dzyaloshinskii-Moriya(DM)spin-orbit interaction with qubit B.We find that the DM interaction can induce the entanglement sudden death(ESD)of the system qubits A and B,andproperly mixing the initial state of the system and adjusting the state of qubit C are two effective methods of controlling ESD. 相似文献
18.
Considering two identical two-level atoms interacting
with a single-mode thermal
field through two-photon processes,
this paper studies the atomic coherence control on the
entanglement between two two-level atoms,
and finds that the entanglement is greatly
enhanced due to the initial atomic coherence. The results show
that the entanglement can be manipulated
by changing the initial
parameters of the system, such as the superposition coefficients
and the relative phases
of the initial atomic coherent state and the mean photon
number of the cavity field. 相似文献
19.
Quantum entanglement in the system of two two-level atoms interacting with a single-mode vacuum field 总被引:5,自引:0,他引:5 下载免费PDF全文
The entanglement properties of the system of two two-level atoms interacting with a single-mode vacuum field are explored. The quantum entanglement between two two-level atoms and a single-mode vacuum field is investigated by using the quantum reduced entropy; the quantum entanglement between two two-level atoms, and that between a single two-level atom and a single-mode vacuum field are studied in terms of the quantum relative entropy. The influences of the atomic dipole--dipole interaction on the quantum entanglement of the system are also discussed. Our results show that three entangled states of two atoms--field, atom--atom, and atom--field can be prepared via two two-level atoms interacting with a single-mode vacuum field. 相似文献