Analytical investigation on interactions among squeezed vacuum and coherent state, coherent vacuum and squeezed state, and among phase squeezed and amplitude squeezed states of light

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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Higher order properties and Bell inequality violation for the three-mode enhanced squeezed state

Canadian Journal of Physics ◽

10.1139/p10-020 ◽

2010 ◽

Vol 88 (5) ◽

pp. 349-356

Author(s):

Shuang-Xi Zhang ◽

Hong-Chun Yuan ◽

Hong-Yi Fan

Keyword(s):

Coherent State ◽

Bell Inequality ◽

Higher Order ◽

Photon Statistics ◽

Squeezed States ◽

Squeezed State ◽

Squeezed Coherent State ◽

Wigner Representation ◽

Squeezing Operator

By extending the usual two-mode squeezing operator S2 = exp[iλ(Q1P2 + Q2P1)] to the three-mode squeezing operator S3 = exp{iλ[Q1(P2 + P3) + Q2(P1 + P3) + Q3(P1 + P2)]}, we obtain the corresponding three-mode squeezed coherent state. The higher order properties of this state, such as higher order squeezing and higher order sub-Possonian photon statistics, are investigated. It is found that the new squeezed state not only can be squeezed to all even orders but also exhibits squeezing enhancement compared with the usual cases. In addition, we examine the violation of the Bell inequality for the three-mode squeezed states by using the formalism of Wigner representation.

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SQUEEZED VACUA AND THE QUANTUM STATISTICS OF COSMOLOGICAL PARTICLE CREATION

International Journal of Modern Physics A ◽

10.1142/s0217751x94000455 ◽

1994 ◽

Vol 09 (07) ◽

pp. 991-1007 ◽

Cited By ~ 49

Author(s):

B. L. HU ◽

G. KANG ◽

A. MATACZ

Keyword(s):

Coherent State ◽

Particle Number ◽

Particle Creation ◽

Space Time ◽

Quantum Statistics ◽

Squeezed States ◽

Quantum Fields ◽

Squeezed State ◽

Initial State ◽

Systematic Description

We use the language of squeezed states to give a systematic description of two issues in cosmological particle creation: (a) Dependence of particle creation on the initial state specified; we consider in particular the number state, the coherent state and the squeezed state; (b) the relation of spontaneous and stimulated particle creation and their dependence on the initial state. We also present results for the fluctuations in particle number in anticipation of its relevance to defining noise in quantum fields and the vacuum susceptibility of space–time.

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Scattering-lens based quantum imaging beyond shot noise

Scientific Reports ◽

10.1038/s41598-021-85846-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Dong Li ◽

Yao Yao

Keyword(s):

Coherent State ◽

Shot Noise ◽

Quantum Noise ◽

Signal To Noise Ratio ◽

Optical Diffraction ◽

Squeezed States ◽

Squeezed State ◽

Signal To Noise ◽

Alternative Scheme ◽

Noise Ratio

AbstractThe scheme of optical imaging using scattering lens can provide a resolution beyond the classical optical diffraction limit with a coherent-state input. Nevertheless, due to the shot noise of the coherent state, the corresponding signal-to-noise ratio and resolution are both still shot-noise-limited. In order to circumvent this problem, we theoretically propose an alternative scheme where the squeezed state (with a sub-shot noise) is considered as input and the quantum noise is then suppressed below the shot-noise level. Consequently, when comparing with the previous imaging scheme (using combination of coherent state and scattering lens), our proposal is able to achieve an enhanced signal-to-noise ratio for a given scattering lens. Meanwhile, it is demonstrated that the resolution is also improved. We believe that this method may afford a new way of using squeezed states and enable a higher performance than that of using coherent state and scattering lens.

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Advantages of the coherent state compared with squeezed state in unidimensional continuous variable quantum key distribution

Quantum Information Processing ◽

10.1007/s11128-018-2118-0 ◽

2018 ◽

Vol 17 (12) ◽

Cited By ~ 3

Author(s):

Xuyang Wang ◽

Yanxia Cao ◽

Pu Wang ◽

Yongmin Li

Keyword(s):

Coherent State ◽

Quantum Key Distribution ◽

Key Distribution ◽

Continuous Variable ◽

Squeezed State

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Comparative analysis of properties for amplified coherent state and amplified squeezed vacuum

Modern Physics Letters B ◽

10.1142/s0217984920503777 ◽

2020 ◽

Vol 34 (33) ◽

pp. 2050377

Author(s):

Yan-Bei Cheng ◽

Sheng-Guo Guan ◽

Zu-Jian Wang ◽

Xue-Xiang Xu

Keyword(s):

Comparative Analysis ◽

Coherent State ◽

Amplification Factor ◽

Annihilation Operator ◽

Photon Number ◽

Matrix Elements ◽

Squeezed Vacuum ◽

Quadrature Squeezing ◽

Antibunching Effect ◽

Analytical Expressions

Two “amplified” quantum states, that is, amplified coherent state (ACS) and amplified squeezed vacuum (ASV), are considered in this paper by applying operator [Formula: see text] on coherent state (CS) and squeezed vacuum (SV), respectively. Here [Formula: see text] [Formula: see text] denotes a amplification factor and [Formula: see text]) denote the creation (annihilation) operator. Along these two lines, we make a comparative analysis of properties for ACS and ASV. The considered properties include density matrix elements, Wigner function, mean photon number, second-order autocorrelation function, and quadrature squeezing. We derive analytical expressions and make numerical simulations for all the properties. The noteworthy results include: (1) the ACS has antibunching and squeezing characters; (2) the ASV will have the bunching and antibunching effect in small initial squeezing.

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Berry phase for the SU(1,1) coherent state

Canadian Journal of Physics ◽

10.1139/p88-157 ◽

1988 ◽

Vol 66 (11) ◽

pp. 978-980 ◽

Cited By ~ 8

Author(s):

Fan Hong-Yi ◽

H. R. Zaidi

Keyword(s):

Coherent State ◽

General Expression ◽

Berry Phase ◽

Squeezed States

We derive a general expression for the Berry phase for the case of the SU(1,1) coherent state. The results are also applicable to one- and two-mode squeezed states.

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