scholarly journals Macroscopic displaced thermal field as the entanglement catalyst

2007 ◽  
Vol 7 (8) ◽  
pp. 775-781
Author(s):  
S.-B. Zheng
Keyword(s):  
Thermal Field ◽  
Cavity Mode ◽  
Thermal State ◽  
Atomic System ◽  
Photon Number ◽  
Resonant Interaction ◽  
Entangled State ◽  
Cavity Field ◽  
Average Photon Number

We show that entanglement of multiple atoms can arise via resonant interaction with a displaced thermal field with a macroscopic photon-number. The cavity field acts as the catalyst, which is disentangled with the atomic system after the operation. Remarkably, the entanglement speed does not decrease as the average photon-number of the mixed thermal state increases. The atoms may evolve to a highly entangled state even when the photon-number of the cavity mode approaches infinity.

NONCLASSICALITY AND DECOHERENCE OF PHOTON-ADDED THERMAL STATE

2010 ◽  
Vol 08 (08) ◽  
pp. 1373-1387 ◽  
Author(s):  
SHU-JING WANG ◽  
XUE-XIANG XU ◽  
SHAN-JUN MA
Keyword(s):  
Thermal State ◽  
Thermal Environment ◽  
Hermite Polynomials ◽  
Photon Number ◽  
Single Variable ◽  
State Characteristic ◽  
Number Formula ◽  
Analytical Expressions ◽  
Average Photon Number ◽  
Photon Number Distribution

Using the normally ordered form of thermal state characteristic of average photon number nc, we introduce the photon-added thermal state (PATS) and investigate its statistical properties, such as Mandel's Q-parameter, photon number distribution (PND), and Wigner function (WF). We then study its decoherence in a thermal environment with average thermal photon number [Formula: see text] and dissipative coefficient κ by deriving analytical expressions of the WF. The nonclassicality is discussed in terms of the negativity of the WF. It is found that the WF is always positive when [Formula: see text] for any number PATS. The expression for time evolution of the PND and the tomogram of PATS are also derived analytically, which are related to hypergeometric function and single variable Hermite polynomials.

PROBABILISTIC TELEPORTATION OF A TWO-ATOM ENTANGLED STATE IN CAVITY QED

2008 ◽  
Vol 22 (13) ◽  
pp. 2129-2137
Author(s):  
JIN-MING LIU ◽  
YI-CAI WANG ◽  
XIAO-QI XIAO
Keyword(s):  
Quantum Channel ◽  
Cavity Qed ◽  
Thermal Field ◽  
Cavity Mode ◽  
Resonant Cavity ◽  
Success Probability ◽  
Entangled State ◽  
Probabilistic Teleportation ◽  
Cavity Decay ◽  
Partially Entangled State

We present two schemes for probabilistically teleporting a two-atom entangled state using a three-atom partially entangled state as the quantum channel in cavity QED with the help of separate atomic measurements. The first scheme is only based on the interaction between two driven atoms and a quantized cavity mode in the large detuning limit, so the effects of both cavity decay and the thermal field are eliminated. In the second scheme, it is necessary to introduce an additional resonant cavity besides the thermal cavity to realize the teleportation, and the corresponding success probability is improved.

Entanglement, Decoherence and Correlations in a Strongly Driven Jaynes-Cummings System

2006 ◽  
Vol 13 (04) ◽  
pp. 437-444 ◽  
Author(s):  
F. Casagrande ◽  
A. Lulli
Keyword(s):  
Thermal Noise ◽  
Cavity Mode ◽  
Resonant Interaction ◽  
Cavity Field ◽  
Unitary Evolution ◽  
Level Atom ◽  
Coherent Field ◽  
Field State ◽  
Atomic Correlation ◽  
Superposition States

We consider the resonant interaction of a cavity mode with a two-level atom that is driven by a coherent field while it crosses the cavity. Starting from the cavity field in a coherent state, we show that the state of the system can reach the maximum entanglement after a unitary evolution for long enough interaction times. Also we illustrate how the generation of cavity field superposition states can allow, in the open system dynamics, the observation of their decoherence in atomic correlation measurements, for any initial cavity field state, and even under the combined effects of dissipation, thermal noise, and atomic pumping.

scholarly journals EFFECTS OF CAVITY-FIELD STATISTICS ON ATOMIC ENTANGLEMENT IN THE JAYNES–CUMMINGS MODEL

2007 ◽  
Vol 05 (01n02) ◽  
pp. 169-177 ◽  
Author(s):  
BIPLAB GHOSH ◽  
A. S. MAJUMDAR ◽  
N. NAYAK
Keyword(s):  
Thermal Field ◽  
Photon Number ◽  
Cavity Field ◽  
Photon Field ◽  
Entanglement Of Formation ◽  
Fock State ◽  
Atomic Entanglement ◽  
Joint State

We study the entanglement properties of a pair of two-level atoms going through a cavity one after another. The initial joint state of two successive atoms that enter the cavity is unentangled. Interactions mediated by the cavity photon field result in the final two-atom state being of a mixed entangled type. We consider the field statistics of the Fock state field, and the thermal field, respectively, inside the cavity. The entanglement of formation of the joint two-atom state is calculated for both these cases as a function of the Rabi angle gt. We present a comparitive study of two-atom entanglement for low and high mean photon number cases corresponding to the different fields statistics.

THE CONCENTRATION PROTOCOL OF A TWO-PARTICLE NON-MAXIMALLY ENTANGLED STATE AMONG THREE CAVITIES

2012 ◽  
Vol 26 (24) ◽  
pp. 1250158
Author(s):  
PENG XU ◽  
LIU YE
Keyword(s):  
Cavity Mode ◽  
Bell State ◽  
Resonant Interaction ◽  
Entangled State ◽  
Photon Detectors ◽  
Maximally Entangled State ◽  
Interaction Detection ◽  
Bell State Measurements ◽  
Separate Cavities

We propose a scheme for concentrating an arbitrary two-particle non-maximally entangled state into a maximally entangled state assisted with three cavities. The scheme involves two interaction–detection cycles and resonant interaction between atom and cavity mode. With the help of the atom trapped in the cavity, the concentration of a two-particle non-maximally entangled state trapped in separate cavities can be realized with a certain probability according to the results of photon detectors. The important feature of our scheme is that we can realize the concentration of an arbitrary two-atom non-maximally entangled state and we do not perform Bell-state measurements.

STUDY ON QUANTUM CORRELATIONS FOR CIRCUIT QED STATES

2013 ◽  
Vol 27 (13) ◽  
pp. 1350056 ◽  
Author(s):  
Y. H. JI ◽  
Y. M. LIU
Keyword(s):  
Quantum Discord ◽  
Relative Phase ◽  
Photon Number ◽  
Quantum Correlations ◽  
Superconducting Qubits ◽  
Squeezed State ◽  
Cavity Field ◽  
Circuit Qed ◽  
Study Results ◽  
Average Photon Number

We investigate the dynamic evolution behaviors of entanglement and geometric quantum discord of coupled superconducting qubits in circuit QED system. We carefully analyze the effect of cavity field quantum state on the quantum entanglement and quantum correlations dynamic behaviors of coupling superconducting qubits. The results show that when the cavity field is in coherent state, with the average photon number increasing, the quantum discord death (including entanglement death) would become more difficult to appear, that is to say prolonging the survival time of quantum correlations will be a benefit for keeping the quantum correlations. When the cavity field is in squeezed state, the squeezed amplitude parameters are all too big or too small to keep the system quantum correlations. However, the further study results show that with the initial relative phase of coupling superconducting increasing, qubits can also keep the quantum correlations.

scholarly journals DYNAMICS OF INFORMATION IN THE PRESENCE OF DEFORMATION

2011 ◽  
Vol 09 (03) ◽  
pp. 937-946 ◽  
Author(s):  
NASSER METWALLY
Keyword(s):  
Mixed State ◽  
Quantum Channel ◽  
Quantum Teleportation ◽  
Cavity Mode ◽  
Atomic System ◽  
Entangled State ◽  
Transmitted Information ◽  
The Cross

The entanglement of atomic system consisting of two atoms interacting with a deformed cavity mode is quantified by the means of Bloch vectors and the cross dyadic of the traveling state inside the cavity. For large value of the deformation, the amplitude of Bloch vectors decrease very fast and consequently, the traveling state turns into mixed state quickly. The generated entangled state is used as quantum channel to implement quantum teleportation protocol. It is shown that both the deformed parameter and the number of photons inside the cavity play a central role in controlling the fidelity of the transmitted information.

ENTANGLING TWO MULTIATOM CLUSTERS VIA A SINGLE-MODE THERMAL FIELD

2011 ◽  
Vol 25 (20) ◽  
pp. 2681-2696 ◽  
Author(s):  
S. R. J. PATRICK ◽  
YANG YANG ◽  
ZHANG-QI YIN ◽  
FU-LI LI
Keyword(s):  
Thermal Field ◽  
Photon Number ◽  
Single Mode ◽  
Cavity Field ◽  
Thermal Photon ◽  
Atom Clusters ◽  
Level Atom ◽  
The Mean ◽  
Single Mode Cavity

We consider a system consisting of two multiple two-level-atom clusters simultaneously interacting with a single-mode cavity field. Entanglement of the two clusters is investigated by use of the negativity measure. We find that the entanglement can be not only induced by a thermal field but also enhanced by increasing the mean thermal photon number.

scholarly journals Optimal time-resolved photon number distribution reconstruction of a cavity field by maximum likelihood

2012 ◽  
Vol 14 (11) ◽  
pp. 115007 ◽  
Author(s):  
C Sayrin ◽  
I Dotsenko ◽  
S Gleyzes ◽  
M Brune ◽  
J M Raimond ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Photon Number ◽  
Optimal Time ◽  
Cavity Field ◽  
Time Resolved ◽  
Number Distribution ◽  
Photon Number Distribution

SOME FEATURES OF SQUEEZED NEGATIVE BINOMIAL STATE

1992 ◽  
Vol 06 (03n04) ◽  
pp. 409-415 ◽  
Author(s):  
AMITABH JOSHI ◽  
S. V. LAWANDE
Keyword(s):  
Electromagnetic Field ◽  
Density Matrix ◽  
Wigner Function ◽  
Negative Binomial ◽  
Thermal State ◽  
Photon Number ◽  
Binomial State ◽  
Relationship Of ◽  
The Relationship ◽  
Photon Number Distribution

Properties of electromagnetic field in the squeezed negative binomial state are investigated in terms of photon number distribution and Wigner function. The relationship of the density matrix of the squeezed negative binomial state to the density matrix of the squeezed thermal state is shown explicitly. The possibility of generation of the negative binomial state is also discussed.

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