Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Communications in Theoretical Physics

Quantum Effects of Bose–Einstein Condensates

Zhao-Xian Yu, Jiao Zhi-Yong, Jinzuo Sun

Published Apr 15, 2004• 4 citations
Publisher

Abstract

In this paper, we study quadrature squeezings of two Bose–Einstein condensates with collision and nonclassical properties of pair entanglement in four wave mixing in Bose–Einstein condensates. With the aid of a numerical method, we find that the two modes (pair entanglement modes) a1 and a2 may exhibit quadrature squeezing, in which they are affected by the initial phase. It is shown that the two pump modes exhibit the same super-Poissonian distribution. The analysis for the mode-mode correlation shows that there always exists a violation of the Cauchy-Schwartz inequality, which means that correlation between the two pump modes is nonclassical.

DOI
10.1088/0253-6102/41/4/593

Related papers

Quantum Statistical Behaviors of Interaction of an Atomic Bose-Einstein Condensate with Laser

Yu Yu, Zhao-Xian, Jiao +1 more

We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-number distribution, while the atomic field is initially in a Fock state, it is found that there is energy exchange between photons and atoms. For the input and output states, the photons and atoms may exhibit the sub-Poissonian distribution. The input and output laser fields may exhibit quadrature squeezing, but for the atomic field, only the output state exhibits quadrature squeezing. It is shown that there exists the violation of the Cauchy-Schwartz inequality, which means that the correlation between photons and atoms is nonclassical.``

理论物理通讯:英文版•Jan 1, 2001•0 citations

Quantum Statistical Behaviors of Interaction of an Atomic Bose–Einstein Condensate with Laser

Zhao-Xian Yu, Jiao Zhi-Yong

We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose–Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-number distribution, while the atomic field is initially in a Fock state, it is found that there is energy exchange between photons and atoms. For the input and output states, the photons and atoms may exhibit the sub-Poissonian distribution. The input and output laser fields may exhibit quadrature squeezing, but for the atomic field, only the output state exhibits quadrature squeezing. It is shown that there exists the violation of the Cauchy–Schwartz inequality, which means that the correlation between photons and atoms is nonclassical.

Communications in Theoretical Physics•Oct 15, 2001•10 citations

Quantum Statistical Properties in Two-Species Bose–Einstein Condensates

Zhao-Xian Yu, Weigang Zhang

We have studied quantum statistical properties in a zero-temperature two-species Bose–Einstein condensate system in the presence of the nonlinear self-interaction of each species, the interspecies nonlinear interaction, and the Josephson-like tunneling interaction. It is found that the two condensates may periodically exhibit sub-Poissonian distribution. It is revealed that the correlation between the two condensates can be nonclassical, which means that there exists a violation of Cauchy–Schwartz inequality. The nonclassical effect about the correlation between the two condensates can be realized experimentally by properly preparing the total number of atoms in the two condensates.

Communications in Theoretical Physics•Jan 15, 2002•2 citations

On the observation of nonclassical excitations in Bose–Einstein condensates

Andreas Finke, Piyush Jain, Silke Weinfurtner

In the recent experimental and theoretical literature well-established nonclassicality criteria from the field of quantum optics have been directly applied to the case of excitations in matter-waves. Among these are violations of Cauchy–Schwarz inequalities, Glauber–Sudarshan P-nonclassicality, sub-Poissonian number-difference squeezing (also known as the two-mode variance) and the criterion of nonseparability. We review the strong connection of these criteria and their meaning in quantum optics, and point out differences in the interpretation between light and matter waves. We then calculate observables for a homogeneous Bose–Einstein condensate undergoing an arbitrary modulation in the interaction parameter at finite initial temperature, within both the quantum theory as well as a classical reference. We conclude that to date in experiments relevant for this scenario nonclassical effects have not conclusively been observed and conjecture that additional, noncommuting, observables have to be measured to this end. Moreover this has important implications for proposed analog gravity models where the observation of nonclassical effects is a major goal.

arXiv:1601.06766•New Journal of Physics•Nov 8, 2016•33 citations

Two-mode nonclassical state via superpositions of two-mode coherent states

Chin-lin Chai

The superposition states from several two-mode coherent states are studied. It is shown that under certain conditions the superposition states may exhibit nonclassical effects, such as two-mode squeezing, violation of the Cauchy-Schwartz inequality, and sub-Poissonian statistics.

Physical Review A•Dec 1, 1992•94 citations

Nonclassical features of entangled coherent states

Muhammad Ashfaq Ahmad, Syed Hamad Bukhari, Salman Naeem Khan +3 more

Nonclassical features of entangled coherent states (two-mode superposition coherent states) based on two coherent states shifted in phase by π/2 are discussed. Analysis of Cauchy–Schwartz inequality, two-mode quadrature squeezing, oscillatory and sub-Poissonian photon statistics show that nonclassicality exists for these states. Furthermore, it is also observed that special states have remarkably strong nonclassical properties than the entangled coherent states based on famous even–odd coherent states.

Journal of Modern Optics•May 6, 2011•13 citations
In this paper, we study quadrature squeezings of two Bose–Einstein condensates with collision and nonclassical properties of pair entanglement in four wave mixing in Bose–Einstein condensates. With the aid of a numerical method, we find that the two modes (pair entanglement modes) a1 and a2 may exhibit quadrature squeezing, in which they are affected by the initial phase. It is shown that the two pump modes exhibit the same super-Poissonian distribution. The analysis for the mode-mode correlation shows that there always exists a violation of the Cauchy-Schwartz inequality, which means that correlation between the two pump modes is nonclassical.
We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-number distribution, while the atomic field is initially in a Fock state, it is found that there is energy exchange between photons and atoms. For the input and output states, the photons and atoms may exhibit the sub-Poissonian distribution. The input and output laser fields may exhibit quadrature squeezing, but for the atomic field, only the output state exhibits quadrature squeezing. It is shown that there exists the violation of the Cauchy-Schwartz inequality, which means that the correlation between photons and atoms is nonclassical.``
We have investigated quantum statistical behaviors of photons and atoms in interaction of an atomic Bose–Einstein condensate with quantized laser field. When the quantized laser field is initially prepared in a superposition state which exhibits holes in its photon-number distribution, while the atomic field is initially in a Fock state, it is found that there is energy exchange between photons and atoms. For the input and output states, the photons and atoms may exhibit the sub-Poissonian distribution. The input and output laser fields may exhibit quadrature squeezing, but for the atomic field, only the output state exhibits quadrature squeezing. It is shown that there exists the violation of the Cauchy–Schwartz inequality, which means that the correlation between photons and atoms is nonclassical.
We have studied quantum statistical properties in a zero-temperature two-species Bose–Einstein condensate system in the presence of the nonlinear self-interaction of each species, the interspecies nonlinear interaction, and the Josephson-like tunneling interaction. It is found that the two condensates may periodically exhibit sub-Poissonian distribution. It is revealed that the correlation between the two condensates can be nonclassical, which means that there exists a violation of Cauchy–Schwartz inequality. The nonclassical effect about the correlation between the two condensates can be realized experimentally by properly preparing the total number of atoms in the two condensates.
In the recent experimental and theoretical literature well-established nonclassicality criteria from the field of quantum optics have been directly applied to the case of excitations in matter-waves. Among these are violations of Cauchy–Schwarz inequalities, Glauber–Sudarshan P-nonclassicality, sub-Poissonian number-difference squeezing (also known as the two-mode variance) and the criterion of nonseparability. We review the strong connection of these criteria and their meaning in quantum optics, and point out differences in the interpretation between light and matter waves. We then calculate observables for a homogeneous Bose–Einstein condensate undergoing an arbitrary modulation in the interaction parameter at finite initial temperature, within both the quantum theory as well as a classical reference. We conclude that to date in experiments relevant for this scenario nonclassical effects have not conclusively been observed and conjecture that additional, noncommuting, observables have to be measured to this end. Moreover this has important implications for proposed analog gravity models where the observation of nonclassical effects is a major goal.
Nonclassical features of entangled coherent states (two-mode superposition coherent states) based on two coherent states shifted in phase by π/2 are discussed. Analysis of Cauchy–Schwartz inequality, two-mode quadrature squeezing, oscillatory and sub-Poissonian photon statistics show that nonclassicality exists for these states. Furthermore, it is also observed that special states have remarkably strong nonclassical properties than the entangled coherent states based on famous even–odd coherent states.