SECOND-ORDER AND AMPLITUDE-SQUARED SQUEEZING OF THE TWO TWO-LEVEL ATOMS WITH SUPERPOSITION STATE PREPARATION

An analysis of the second-order and amplitude-squared (AS) squeezing is presented for the two atoms prepared in a two-atom squeezed state using coherent and squeezed field inputs. The system produce strong sqeezing and superposition angle (θ) is more effective for small values of average photon number [Formula: see text] as compared to that of large one. The degree of squeezing of both types increases as θ increases for coherent field input with small [Formula: see text]. Some values of θ for the initial field in a squeezed-vacuum state with any value of input squeezing can make one of the quadrature of the both types of squeezing permanently squeezed for T≥0. For the initial field in a more general squeezed state, the second-order and AS squeezing behave randomly for different values of θ.

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AMPLITUDE-SQUARED SQUEEZING IN THE m-PHOTON JAYNES-CUMMINGS MODEL WITH SQUEEZED FIELD INPUT

International Journal of Modern Physics B ◽

10.1142/s0217979292001213 ◽

1992 ◽

Vol 06 (13) ◽

pp. 2409-2422 ◽

Cited By ~ 1

Author(s):

MUBEEN A. MIR ◽

M.S.K. RAZMI

Keyword(s):

Ground State ◽

Photon Number ◽

Vacuum State ◽

Squeezed States ◽

Initial Field ◽

Squeezed Vacuum State ◽

Squeezed Vacuum ◽

Number Formula ◽

Average Photon Number ◽

Intensity Dependent Coupling

Amplitude-squared (AS) squeezing has been investigated for the m-photon Jaynes-Cummings model assuming the field to be initially in the squeezed states. The role played by intensity-dependent coupling has also been discussed. It has been shown that for the large initial average photon number [Formula: see text] with odd values of m, AS squeezing revokes permanently whereas with even values it recurs periodically. As m increases the revocation is hastened and the duration of occurrence decreases. Higher values of m for the initial field in a squeezed vacuum state can make one of the quadrature permanently squeezed. The AS squeezing behavior for two initial states of the atom, i.e., ground state versus excited state is also compared.

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LEGENDRE POLYNOMIALS AS THE NORMALIZATION OF PHOTON-SUBTRACTED SQUEEZED STATES

Modern Physics Letters A ◽

10.1142/s021773230902996x ◽

2009 ◽

Vol 24 (20) ◽

pp. 1597-1603 ◽

Cited By ~ 10

Author(s):

HONG-YI FAN ◽

LI-YUN HU ◽

XUE-XIANG XU

Keyword(s):

Legendre Polynomial ◽

Legendre Polynomials ◽

Hermite Polynomial ◽

Vacuum State ◽

Squeezed States ◽

Squeezed State ◽

Normalization Factor ◽

Squeezed Vacuum State ◽

Squeezed Vacuum ◽

Excitation State

By converting the photon-subtracted squeezed state (PSSS) to a squeezed Hermite-polynomial excitation state we find that the normalization factor of PSSS is an m-order Legendre polynomial of the squeezing parameter, where m is the number of subtracted photons. Some new relations about the Legendre polynomials are obtained by this analysis. We also show that the PSSS can also be treated as a Hermite-polynomial excitation on squeezed vacuum state.

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NONCLASSICALITY AND DECOHERENCE OF PHOTON-ADDED THERMAL STATE

International Journal of Quantum Information ◽

10.1142/s0219749910006162 ◽

2010 ◽

Vol 08 (08) ◽

pp. 1373-1387 ◽

Cited By ~ 1

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.

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SQUEEZING ENHANCED THREE-MODE ENTANGLED STATE

Modern Physics Letters B ◽

10.1142/s0217984908016662 ◽

2008 ◽

Vol 22 (22) ◽

pp. 2055-2061 ◽

Cited By ~ 2

Author(s):

LI-YUN HU ◽

HONG-YI FAN

Keyword(s):

Fock Space ◽

Vacuum State ◽

Entangled State ◽

Squeezed State ◽

Squeezed Vacuum State ◽

Squeezed Vacuum

By virtue of the technique of integration within an ordered product of operators (Fan et al., Ann. Phys.321 (2006) 480) we construct a kind of three-mode entangled squeezed state in the Fock space, which exhibits stronger squeezing in one quadrature than that of the usual two-mode squeezed vacuum state.

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ON THE NORMALIZED TWO-MODE PHOTON-SUBTRACTED SQUEEZED VACUUM STATE

Modern Physics Letters A ◽

10.1142/s0217732309031168 ◽

2009 ◽

Vol 24 (32) ◽

pp. 2623-2630 ◽

Cited By ~ 9

Author(s):

XUE-XIANG XU ◽

LI-YUN HU ◽

HONG-YI FAN

Keyword(s):

Jacobi Polynomial ◽

Hermite Polynomial ◽

Jacobi Polynomials ◽

Vacuum State ◽

Squeezed State ◽

Squeezed Vacuum State ◽

Squeezed Vacuum ◽

Excitation State

We show that the two-mode photon-subtracted squeezed state (TPSSS) is a squeezed two-variable Hermite polynomial excitation state, and we can therefore determine its normalization as a Jacobi polynomial of the squeezing parameter. Some new relations about the Jacobi polynomials are obtained by this analysis. We also show that the TPSSS can be treated as a two-variable Hermite-polynomial excitation on squeezed vacuum state. The technique of integration within an ordered product of operators brings convenience in our derivation.

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STUDY ON QUANTUM CORRELATIONS FOR CIRCUIT QED STATES

International Journal of Modern Physics B ◽

10.1142/s0217979213500562 ◽

2013 ◽

Vol 27 (13) ◽

pp. 1350056 ◽

Cited By ~ 1

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.

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Thermo vacuum state for Gaussian-enhanced chaotic light

Modern Physics Letters B ◽

10.1142/s0217984917501512 ◽

2017 ◽

Vol 31 (13) ◽

pp. 1750151

Author(s):

Wei-Feng Wu ◽

Hong-Yi Fan

Keyword(s):

Density Operator ◽

Quantum Fluctuation ◽

Photon Number ◽

Vacuum State ◽

Second Order ◽

Normalization Constant ◽

Partial Trace ◽

Degree Of Coherence ◽

Order Degree ◽

Thermo Vacuum State

In nature, there exists superposition of Gaussian light and chaotic light, so we introduce the density operator for describing the Gaussian-enhanced chaotic light (GECL). By virtue of the method of integration within ordered product (IWOP) of operators, we derive its normalization constant. Then, by virtue of the partial trace method, we derive its thermo vacuum state and this may greatly simplify the calculation of photon number average and quantum fluctuation in GECL. It is demonstrated that the second-order degree of coherence of GECL is larger than 2.

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Exact solutions of the equation for composite scalar particles in quantized electromagnetic waves

Canadian Journal of Physics ◽

10.1139/p03-079 ◽

2003 ◽

Vol 81 (7) ◽

pp. 953-969

Author(s):

S I Kruglov

Keyword(s):

Electromagnetic Wave ◽

Exact Solutions ◽

Electromagnetic Waves ◽

Photon Number ◽

Scalar Particle ◽

Photon Density ◽

Electromagnetic Plane Wave ◽

Scalar Particles ◽

Number Formula ◽

Average Photon Number

An equation is considered for a composite scalar particle with polarizabilities in an external quantized electromagnetic plane wave. This equation is reduced to a system of equations for an infinite number of interacting oscillators. After diagonalization, we come to equations for free oscillators. As a result, exact solutions of the equation for a particle are found in a plane-quantized electromagnetic wave of arbitrary polarization. As a particular case, the solution for monochromatic electromagnetic waves is considered. The relativistic coherent states of a particle are constructed using the Poisson distribution of photon numbers. In the limit, when the average photon number [Formula: see text] and the volume V of the quantization tend to infinity (but the photon density [Formula: see text] /V remains constant), the wave function converts to the solution corresponding to the external classical electromagnetic wave. PACS Nos.: 14.40.Aq, 13.40.Ks, 13.40.-f

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