A new approach to the time evolution of characteristic function of the density operator obtained by virtue of thermal entangled state representation

We present a new approach to finding multipartite entangled state representation by decomposing normally ordered Gaussian-form operator in completeness relation, the technique of integration within an ordered product (IWOP) of operators is essential in this searching.

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MULTIPARTITE COHERENT ENTANGLED STATE OF CONTINUOUS VARIABLES: STRUCTURE AND GENERATION

International Journal of Modern Physics A ◽

10.1142/s0217751x09043341 ◽

2009 ◽

Vol 24 (14) ◽

pp. 2689-2701 ◽

Cited By ~ 6

Author(s):

LI-YUN HU ◽

HONG-YI FAN

Keyword(s):

Wigner Function ◽

Quantum Teleportation ◽

Entangled State ◽

Entangled State Representation ◽

Continuous Variables ◽

State Representation ◽

New Approach ◽

Beam Splitters ◽

Multipartite Entangled State

Motivated by the new approach to finding multipartite entangled state representation [Int. J. Mod. Phys. A22, 4481 (2007)], we construct the multipartite coherent entangled state (MCES) of continuous variables which exhibits both coherent state's and entangled state's properties. A protocol of generating such an MCES is proposed by using beam splitters in a sequence. Applications of MCES in studying generalized Wigner function, squeezing and quantum teleportation are discussed.

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THE MIXED COHERENT STATE REPRESENTATION OF THE DENSITY OPERATOR IN THERMO-FIELD DYNAMICS

Modern Physics Letters B ◽

10.1142/s0217984907012694 ◽

2007 ◽

Vol 21 (04) ◽

pp. 183-188 ◽

Cited By ~ 17

Author(s):

H.-Y. FAN ◽

H.-L. LU

Keyword(s):

Coherent State ◽

Density Operator ◽

Master Equations ◽

Entangled State ◽

Entangled State Representation ◽

State Representation ◽

Thermo Field Dynamics

In the framework of thermo-field dynamics, invented by Umezawa et al., we construct a mixed coherent state representation of density operator ρ. This new representation is useful because it provides an approach to retrieve ρ from its c-number solution of master equations in the entangled state representation.

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ENERGY SPECTRUM OF MOTT–WANNIER EXCITON STUDIED BY VIRTUE OF THE EXCITON ENTANGLED STATE REPRESENTATION INSTEAD OF K·P PERTURBATION THEORY

Modern Physics Letters B ◽

10.1142/s0217984905008645 ◽

2005 ◽

Vol 19 (13n14) ◽

pp. 637-642 ◽

Cited By ~ 1

Author(s):

HONG-YI FAN ◽

HUI ZOU ◽

YUE FAN ◽

QIU-YU LIU

Keyword(s):

Perturbation Theory ◽

Energy Spectrum ◽

Entangled State ◽

Entangled State Representation ◽

State Representation ◽

New Approach

We introduce the exciton entangled state. We show that the energy spectrum of Mott–Wannier exciton can be exactly derived by virtue of the entangled state representation. In contrast to the K · P perturbation theory this new approach seems non-perturbative, direct and exact.

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OPERATOR-SUM REPRESENTATION OF DENSITY OPERATORS AS SOLUTIONS TO MASTER EQUATIONS OBTAINED VIA THE ENTANGLED STATE APPROACH

Modern Physics Letters B ◽

10.1142/s0217984908017072 ◽

2008 ◽

Vol 22 (25) ◽

pp. 2435-2468 ◽

Cited By ~ 83

Author(s):

HONG-YI FAN ◽

LI-YUN HU

Keyword(s):

Point Of View ◽

Master Equations ◽

Entangled State ◽

Entangled State Representation ◽

State Representation ◽

Partial Trace ◽

New Approach ◽

Density Operators ◽

Phase Sensitive ◽

System Mode

We solve various master equations to obtain density operators' infinite operator-sum representation via a new approach, i.e., by virtue of the thermo-entangled state representation that has a fictitious mode as a counterpart mode of the system mode. The corresponding Kraus operators from the point of view of quantum channel are derived, whose normalization conditions are proved. Miscellaneous characters possessed by different quantum channels, such as decoherence, phase diffusion, damping, and amplification, can be shown explicitly in the entangled state representation of the density operators. Squeezing transformation is applied to the density operator for decoherence to generate a master equation for describing the phase sensitive process. Partial trace method for deriving new density operators is also introduced. Throughout our discussion, the technique of integration within an ordered product (IWOP) of operators is fully used.

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