scholarly journals Purification of entangled coherent states

2002 ◽  
Vol 2 (3) ◽  
pp. 208-221
Author(s):  
H. Jeong ◽  
M.S. Kim
Keyword(s):  
Decay Time ◽  
Coherent States ◽  
Nonlinear Interactions ◽  
Mixed States ◽  
Entanglement Purification ◽  
Beam Splitters ◽  
Purification Scheme ◽  
Entangled Coherent States

We suggest an entanglement purification scheme for mixed entangled coherent states using 50-50 beam splitters and photodetectors. This scheme is directly applicable for mixed entangled coherent states of the Werner type, and can be useful for general mixed states using additional nonlinear interactions. We apply our scheme to entangled coherent states decohered in a vacuum environment and find the decay time until which they can be purified.

Two-party QPC with polarization-entangled Bell states and the coherent states

2014 ◽  
Vol 14 (3&4) ◽  
pp. 236-254
Author(s):  
Xiao-Ming Xiu ◽  
Li Dong ◽  
Hong-Zhi Shen ◽  
Ya-Jun Gao ◽  
X. X. Yi
Keyword(s):  
Coherent States ◽  
Single Photon ◽  
The Other ◽  
Bell States ◽  
Third Party ◽  
Nonlinear Interactions ◽  
Analysis Method ◽  
Beam Splitters ◽  
Kerr Media ◽  
Einstein Podolsky Rosen

We propose a protocol of quantum privacy comparison with polarization-entangled Einstein-Podolsky-Rosen (Bell) states and the coherent states. One of two legitimate participants, Alice, prepares polarization-entangled Bell states and keeps one photon of each photon pair and sends the other photons to the third party, Charlie. Receiving the photons, Charlie performs single-photon transformation operations on them and then sends them to the other legitimate participant, Bob. Three participants adopt parity analysis method to check the distribution security of Bell states. Exploiting polarization beam splitters and nonlinear interactions mediated by the probe coherent states in Kerr media, Alice and Bob check the parities of their photons using the bases of $\{\ket H, \ket V\}$ or $\{\ket +, \ket -\}$. On the basis of the parity analysis outcomes and Charlie's publicized information, they can analyze the security of the distributed quantum channel. Confirming secure distribution of the shared Bell states, two participants perform respective parity measurements on the privacy photons and own photons of Bell states, and then send the results to Charlie. According to information provided by two legitimate participants and his single-qubit transformation operations, Charlie compares the privacy information of Alice and Bob and publicizes the conclusion.

Generation of cluster-type entangled coherent states using weak nonlinearities

2011 ◽  
Vol 11 (1&2) ◽  
pp. 124-141
Author(s):  
Nguyen B. An ◽  
Kisik Kim ◽  
Jaewan Kim
Keyword(s):  
Coherent States ◽  
Single Photon ◽  
Optical Devices ◽  
Phase Shifters ◽  
Intense Laser ◽  
Laser Beams ◽  
Beam Splitters ◽  
Photo Detectors ◽  
Cluster Type ◽  
Entangled Coherent States

We propose a scheme to generate a recently introduced type of entangled coherent states using realistic weak cross-Kerr nonlinearities and intense laser beams. An intense laser can be filtered to make a faint one to be used for production of a single photon which is necessary in our scheme. The optical devices used are conventional ones such as interferometer, mirrors, beam-splitters, phase-shifters and photo-detectors. We also provide a detailed analysis on the effects of possible imperfections and decoherence showing that our scheme is robust against such effects.

Measurement-based entanglement purification for entangled coherent states

2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Pei-Shun Yan ◽  
Lan Zhou ◽  
Wei Zhong ◽  
Yu-Bo Sheng
Keyword(s):  
Coherent States ◽  
Entanglement Purification ◽  
Entangled Coherent States

A GENERATION SCHEME OF THE DISTRIBUTED FOUR-PHOTON CLUSTER-TYPE POLARIZATION-ENTANGLED STATES EXPLOITING THE INTEGRATION OF ENTANGLEMENT GATES AND THE CONTROLLED PHASE GATE

2013 ◽  
Vol 11 (07) ◽  
pp. 1350064
Author(s):  
LI DONG ◽  
JUN-XI WANG ◽  
XIAO-MING XIU ◽  
HAI-KUAN DONG ◽  
DAN LI ◽  
...  
Keyword(s):  
Coherent States ◽  
High Efficiency ◽  
Entangled States ◽  
Nonlinear Interactions ◽  
Optical Elements ◽  
Beam Splitters ◽  
Einstein Podolsky Rosen ◽  
Phase Gate ◽  
Controlled Phase Gate ◽  
Cluster Type

We propose a scheme for preparing the distributed four-photon cluster-type polarization-entangled states associated with the integration of the controlled phase gate and two kinds of entanglement gates. Employing weak cross-Kerr nonlinear interactions and Homodyne measurement, two individual photons entangle together based on the bus function of coherent states. Assisted by optical elements mainly including polarization beam splitters, the entanglement of the signal photons is converted from the spatial mode to the polarization mode. The application of classical feed forward provides the high-efficiency to the preparation of Einstein–Podolsky–Rosen (EPR) states, Greenberger–Horne–Zeilinger (GHZ) states, and four-photon cluster-type polarization-entangled states. With regard to the four-photon cluster-type state, it can be generated in two distributed nodes with less experimental requirements, integrating the features of three logical gates.

ENTANGLEMENT MEASURE OF BIPARTITE SYSTEM STATES

2010 ◽  
Vol 07 (06) ◽  
pp. 1051-1064 ◽  
Author(s):  
K. BERRADA ◽  
Y. HASSOUNI
Keyword(s):  
Coherent States ◽  
Linear Entropy ◽  
Entanglement Measure ◽  
Mixed States ◽  
Maximal Entanglement ◽  
Bipartite System ◽  
Pure States ◽  
System States ◽  
Entangled Coherent States

Linear entropy as a measure of entanglement is applied to explain conditions for minimal and maximal entanglement of bipartite nonorthogonal pure states. We formulate this measure in terms of the amplitudes of coherent states in the case of entangled coherent states and calculate the conditions. We generalize this formalism to the case of bipartite mixed states and show that the entanglement measure is also a function of the probabilities.

scholarly journals Bipartite quantum channels using multipartite cluster-type entangled coherent states

2010 ◽  
Vol 81 (4) ◽  
Author(s):  
P. P. Munhoz ◽  
J. A. Roversi ◽  
A. Vidiella-Barranco ◽  
F. L. Semião
Keyword(s):  
Coherent States ◽  
Quantum Channels ◽  
Cluster Type ◽  
Entangled Coherent States

scholarly journals Entangled coherent states under dissipation

2010 ◽  
Vol 283 (19) ◽  
pp. 3825-3829 ◽  
Author(s):  
F. Lastra ◽  
G. Romero ◽  
C.E. López ◽  
N. Zagury ◽  
J.C. Retamal
Keyword(s):  
Coherent States ◽  
Entangled Coherent States
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