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Two-mode squeezed state of nanomechanical resonators

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Applied Mathematics and Mechanics(English Edition) 2009年第9期30卷 1161-1167页

作者：范瑞琴羊红光白志明 Department of Mathematics and Physics Shijiazhuang Railway Institute College of Science Hebei University of Science and Technology

In this paper, we introduce a flexible model for the control and measurement of NAMRs （nanomechanical resonators）. We obtain the free Hamiltonian of the dcSQUID （direct current superconducting quantum interference device） and the interaction Hamiltonian between these two NAMRs and the dc-SQUID by introducing the annihilation and creation operators under the rotating wave approximation. We can treat the mode of the dc-SQUID as a classical field. In the Heisenberg picture, the generation of two-mode squeezed states of two nanomechanical resonators is shown by their collective coordinate and momentum operators.

关键词： squeezed state two-mode mechanical resonator

10-Hertz squeezed light source generation on the cesium D_(2)line using single photon modulation

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Frontiers of physics 2023年第3期18卷 167-174页

作者： Guan-Hua Zuo Yu-Chi Zhang Gang Li Peng-Fei Zhang Peng-Fei Yang Yan-Qiang Guo Shi-Yao Zhu Tian-Cai Zhang state Key Laboratory of Quantum Optics and Quantum Optics Devices Collaborative Innovation Center of Extreme OpticsInstitute of Opto-ElectronicsShanxi UniversityTaiyuan 030006China College of Physics and Electronic Engineering Shanxi UniversityTaiyuan 030006China Department of Physics Zhejiang UniversityHangzhou 310027China Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi ProvinceCollege of Physics and OptoelectronicsTaiyuan University of TechnologyTaiyuan 030024China

Generation of squeezed light source is a promising technique to overcome the standard quantum limit in precision measurement.Here,we demonstrate an experimental generation of quadrature squeezing resonating on the cesium D_(2)line down to 10 Hz for the first time.The maximum squeezing in audio frequency band is 5.57 dB.Moreover,we have presented a singlephoton modulation locking to control the squeezing angle,while effectively suppressing the influence of laser noise on low-frequency squeezing.The whole system operates steadily for hours.The generated low-frequency squeezed light source can be applied in quantum metrology,light–matter interaction investigation and quantum memory in the audio frequency band and even below.

关键词： squeezed state optical parametric amplifier low-frequency squeezing

Generation of a new bipartite coherent-entangled state and its applications

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Chinese Physics B 2012年第3期21卷 51-55页

作者：张宝来孟祥国王继锁 Dongchang College of Liaocheng University Department of Physics Liaocheng University Shandong Provincial Key Laboratory of Laser Polarization and Information Technology College of Physics and EngineeringQufu Normal University

A new bipartite coherent-entangled state is introduced in the two-mode Fock space, which exhibits the properties of both a coherent state and an entangled state. The set of coherent-entangled states makes up a complete and partly nonorthogonal representation. A simple experimental scheme to produce the coherent-entangled state using an asymmetric beamsplitter is proposed. Some applications of the coherent-entangled state in quantum optics are also oresented.

关键词： bipartite coherent-entangled state asymmetric beamsplitter Einstein-Podolsky-Rosen entangled state squeezed state

Demonstration of eight-partite two-diamond shape cluster state for continuous variables

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Frontiers of physics 2013年第1期8卷 20-26页

作者： Xiao-Long Su Shu-Hong Hao Ya-Ping Zhao Xiao-Wei Deng Xiao-Jun Jia Chang-De Xie Kun-Chi Peng state Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University Taiyuan 030006 China

Multipartite entangled state is the basic resource for implementing quantum information networks and quantum computation. In this paper, we present the experimental demonstration of the eight-partite two-diamond shape cluster states for continuous variables, which consist of eight spatially separated and entangled optical modes. Eight resource squeezed states of light with classical coherence are produced by four nondegenerate optical parametric amplifiers and then they are transformed to the eight-partite two-diamond shape cluster states by a specially designed linear optical network. Since the spatially separated multipartite entangled state can be prepared off-line, it can be conveniently applied in the future quantum technology.

关键词： quantum computation continuous variable cluster state squeezed state

Generation of squeezed TEM_(01) modes with periodically poled KTiOPO_4 crystal

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Chinese Physics B 2011年第6期20卷 30-33页

作者：杨荣国孙恒信张俊香郜江瑞 state Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University

Spatial quantum optics and quantum information based on the high order transverse mode are of importance for the super-resolution measurement beyond the quantum noise level. We demonstrated experimentally the transverse plane TEM01 Hermite Gauss quantum squeezing. The squeezed TEM01 mode is generated in a degenerate optical parametric amplifier with the nonlinear crystal of periodically poled KTiOPO4. The level of 2.2-dB squeezing is measured using a spatial balance homodyne detection system.

关键词： Hermite Gauss mode squeezed state degenerate optical parametric amplifier

Representations of coherent and squeezed states in an extended two-parameter Fock space

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Chinese Physics C 2012年第8期36卷 703-709页

作者： M. K. Tavassoly M. H. Lake Atomic and Molecular Group Faculty of Physics Yazd University Yazd Iran Photonics Research Group Engineering Research Center Yazd University Yazd Iran

Recently an f -deformed Fock space which is spanned by ｜ n λ was introduced. These bases are the eigenstates of a deformed non-Hermitian Hamiltonian. In this contribution, we will use rather new nonorthogonal basis vectors for the construction of coherent and squeezed states, which in special case lead to the earlier known states. For this purpose, we first generalize the previously introduced Fock space spanned by ｜ n λ bases, to a new one, spanned by extended two-parameters bases ｜ n λ 1 ,λ 2 . These bases are now the eigenstates of a non-Hermitian Hamiltonian H λ 1 ,λ 2 = a λ 1 ,λ 2 a ＋ 1 2 , where a λ 1 ,λ 2 = a ＋ λ 1 a ＋ λ 2 and a are, respectively, the deformed creation and ordinary bosonic annihilation operators. The bases ｜ n λ 1 ,λ 2 are nonorthogonal （squeezed states）, but normalizable. Then, we deduce the new representations of coherent and squeezed states in our two-parameter Fock space. Finally, we discuss the quantum statistical properties, as well as the non-classical properties of the obtained states numerically.

关键词： coherent state squeezed state representation theory quantum statistics non-orthogonal bases

Entanglement of coherent superposition of photon-subtraction squeezed vacuum

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Frontiers of physics 2017年第5期12卷 159-169页

作者： Cun-Jin Liu Wei Ye Wei-Dong Zhou Hao-Liang Zhang Jie-Hui Huang Li-Yun Hu Center for Quantum Science and Technology Jiangxi Normal University Nanchang 330022 China

A new kind of non-Gaussian quantum state is introduced by applying nonlocal coherent superposition （τa＋ sb）^m of photon subtraction to two single-mode squeezed vacuum states, and the properties of entanglement are investigated according to the degree of entanglement and the average fidelity of quantum teleportation. The state can be seen as a single-variable Hermitian polynomial excited squeezed vacuum state, and its normalization factor is related to the Legendre polynomial. It is shown that, for τ = s, the maximum fidelity can be achieved, even over the classical limit （1/2）, only for even- order operation m and equivalent squeezing parameters in a certain region. However, the maximum entanglement can be achieved for squeezing parameters with a π phase difference. These indicate that the optimal realizations of fidelity and entanglement could be different from one another. In addition, the parameter τ/s has an obvious effect on entanglement and fidelity.

关键词： non-Gaussian operation quantum entanglement squeezed state

Nonstandard Unitary Transformations of Quantum states

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Journal of Applied Mathematics and Physics 2023年第9期11卷 2568-2575页

作者： Gombojav O. Ariunbold Department of Physics and Astronomy Mississippi State University Starkville MS USA

In quantum optics, unitary transformations of arbitrary states are evaluated by using the Taylor series expansion. However, this traditional approach can become cumbersome for the transformations involving non-commuting operators. Addressing this issue, a nonstandard unitary transformation technique is highlighted here with new perspective. In a spirit of “quantum” series expansions, the transition probabilities between initial and final states, such as displaced, squeezed and other nonlinearly transformed coherent states are obtained both numerically and analytically. This paper concludes that, although this technique is novel, its implementations for more extended systems are needed.

关键词： Taylor Series Unitary Transformation Temporal Evolution Displaced state Coherent state squeezed state Two-Mode squeezed state Holstein-Primakoff state

Quantum Entropy of a Cooper-Pair Box in a Single-Mode Cavity Field

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Journal of Beijing Institute of Technology 2005年第4期14卷 442-444页

作者：张春雨邹健邵彬 School of Science Beijing Institute of Technology Beijing100081 China

A Cooper-pair box biased by a classical voltage and also irradiated by a squeezed state field is considered in order to find new ways to quantum communication and calculation. The quantum dynamics of the Cooper-pair box and the entanglement which is the core theoretics of quantum communication and calculation is investigated in this system, which is related to the squeezing parameter of the squeezed state, A model of Hamiltonian which represents the interaction between box and quantum field is introduced. Finally, the relationship between the entanglement and the squeezing parameter of the squeezed state is demonstrated.

关键词： quantum entropy entanglement squeezed state Cooper-pair box