Linear instability and adiabaticity of a dark state during conversion of two species of fermionic atoms to stable molecules

In the present paper, we investigate the linear instability and adiabaticity of a dark state during conversion of two species of fermionic atoms to stable molecules through the stimulated Raman adiabatic passage aided by Feshbach resonance. We analytically obtain the regions for the appearance of linear instability. Moreover, taking 40K and 6Li atom molecule conversion systems as examples, we give the unstable regions numerically. We also attempt to obtain the adiabatic criterion for this nonlinear system with classical adiabatic dynamics and study the adibaticity of the dark state with the adiabatic condition.

Instability, adiabaticity, and controlling effects of external fields for the dark state in a homonuclear atom tetramer conversion system

In the present paper, we investigate the instability, adiabaticity, and controlling effects of external fields for a dark state in a homonuclear atom-tetramer conversion that is implemented by a generalized stimulated Raman adiabatic passage. We analytically obtain the regions for the appearance of dynamical instability and study the adiabatic evolution by a newly defined adiabatic fidelity. Moreover, the effects of the external field parameters and the spontaneous emissions on the conversion efficiency are also investigated.

Investigation of ultracold atoms and molecules in a dark magneto-optical trap

In this paper, ultracold atoms and molecules in a dark magneto-optical trap （MOT） are studied via depumping the cesium cold atoms into the dark hyperfine ground state. The collision rate is reduced to 0.45 s-1 and the density of the atoms is increased to 5.6 × 1011 cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15. The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately. The experimental results are analyzed by using the perturbative quantum approach.

Position Dependent Spontaneous Emission Spectra of a Λ-Type Atomic System Embedded in a Defective Photonic Crystal

We investigate the position dependent spontaneous emission spectra of a Λ-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap.It is shown that,for the atom at the defect location,we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode.While,when the atom is far from the defect location(or in the absence of the defect mode),the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges.On the other hand,we have a four-peak spectrum for the atom at the space in between.Moreover,the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described.It is shown that the atoms embedded in high(low) dielectric regions far from the defect location,effectively couple to the modes of the lower(upper) photonic band.However,the atoms embedded in high dielectric or low dielectric regions at the defect location,are coupled mainly to the defect modes.While,the atoms uniformly embedded in high(low) dielectric regions with a normal distance from the defect location,are coupled to both of defect and lower(upper) photonic band modes.

<i>L_α</i>Line of Dark Positronium as a Nongravitational Detection of DM

An attempt to predict the new atomic dark matter lines is done on the example of a dark lepton atom-positronium. Its Layman-alpha line with the energy near 3 GeV may be observable if the appropriate conditions are realized. For this we have studied a γ-ray excess in the center of our galaxy. In principle, this excess may be produced by the Lα line of a dark positronium in the medium with Compton scattering. The possibility of observations of an annihilation line (E^300 TeV) of dark positronium is also predicted. Other proposals to observe the atomic dark matter are shortly described. Besides, Hα line (1.3μ) of usual positronum must be observable in the direction on the center of our galaxy.

Dark Matter Interacts with Electromagnetic Waves

The large-scale structure of DM cannot be directly seen, but it is believed it can be inferred from the distribution of visible galaxies formed from ordinary matter. Bright visible galaxies that emit the Lyman α (Lyα) emission line of the hydrogen atom (Lyα galaxies) are used to observe the large-scale structure of distant space. However, recently Momose et al. have reported cases where the large-scale structures of DM indicated by Lyα galaxies and other galaxies fail to match. This raises the possibility that Lyα galaxies may not correctly indicate the large-scale structure of DM. In the currently accepted cold DM model, DM and neutral hydrogen gas are thought to interact only through the mutual effects of gravity. However, according to Suto, DM and ordinary matter are like two sides of the same coin. By giving and receiving approximately 2mec2 (1.022 MeV), it is possible to mutually convert between the two. If, in future observations of the density distribution of interstellar gas using Lyα emission lines, unexpected data is obtained that cannot be explained based only on absorption by neutral hydrogen gas, then the author believes the problem can be solved with Suto’s DM model.

My C.G.S.I.S.A.H. Theory of Dark Matter

Theory and observations concerning the cosmic reionization epoch are briefly discussed in the context of recent observations attributed to dark matter. A case is made that cold ground state interstellar atomic hydrogen of average density of about one atom per cubic centimeter (1.67 × 10-21?kg&#183;m-3?or 1.67 × 10-24?g&#183;cm-3) appears to be the most likely candidate to explain these observations.

原子磁力仪在异常作用力及类轴子暗物质探测中的应用

简述了异常相互作用力及类轴子暗物质的理论模型,回顾了近年来国内外研究人员使用原子磁力仪和共磁力仪等进行自旋相关的非磁性力探测和暗物质搜寻的技术方案,归纳了迄今为止对自旋和速度相关相互作用、自旋引力相互作用、类轴子暗物质场梯度与核子的耦合强度的探测结果。在此基础上,本文对该领域未来的发展方向进行了展望,通过分析和抑制系统误差、寻找新的探测方案等方法,有望为自旋相关相互作用的耦合参数空间提供更严格的约束,在更广泛的质量范围内对类轴子暗物质与标准模型费米子的耦合给出更严格的界定。

高性能被动型CPT原子钟发展趋势

运用单一圆偏光构型达成CPT态会产生极化暗态使得CPT信号对比度较低。因此,传统的CPT原子钟频率稳定度指标不高。为提高CPT信号对比度从而提高CPT原子钟性能,各种消除极化暗态的方案不断被提出并获得研究,这些方案可以根据所使用的激光偏振状态及其产生方式分为平行线偏振光构型、相位延迟的σ^(+)-σ^(-)构型、推挽光泵浦构型、垂直线偏振光构型、偏振调制构型。基于这些方案的原理和发展水平,对比分析各个方案的优缺点和改进方案,可探索不同需求条件下高性能原子钟新的发展方向。

Theory to the Mystery of the Super Massive Black Holes

Vera Rubin measured the rotational speeds of galaxies, Ref. [1] 1983, and she found that the masses of galaxies were not enough to produce the measured speeds of rotation. Therefore, it was inferred that there must be an unknown matter which is many times the known visible and dark matter. In this study, the solution to the dark matter mystery of spiral galaxies is a four-dimensional mass in the space of four distance dimensions, coordinates: x,y,z,x', in which x' is the fourth distance dimension. The four-dimensional mass is a black hole, and it generates the main gravitation field of the galaxy. This mysterious black hole is located in the fourth dimension at the distance x' = X'. The rotational speed distribution curves of the galaxy NGC 3198 have been presented in Ref. [2]. The speed distribution curve of the galactic halo in that publication corresponds to the speed distribution curve of the four-dimensional black hole in this study. In order to find out how well this four-dimensional model functions, the speed distribution curve of the four-dimensional black hole was calculated, and it was compared with the halo curve of Ref. [2]. The conclusion was that the calculated speed distribution curve of the black hole was a good match to the halo curve of Ref. [2]. Furthermore, the rotational speed distribution curves of the four-dimensional black hole were calculated by using different values of the reduced distance X', which yielded at the distance X' = 0 a black hole of radius R = 7.7 × 1017 m. By using the relativistic Lorentz transformation, it was shown in this study that a star falling into the four-dimensional black hole remains rotating it at near speed of light, and cannot fall into the actual black hole.

Ether as the Fundamental Substance of the Creation of the Universe

The paper analyzes the concept of Ether and substantiates the necessity of its existence as a physical reality, which arises within the framework of the concept developed by the authors of the work. The authors come to the conclusion that the existence of Ether in two different forms, plays an exceptional role in the formation of Dark Matter and Dark Energy and leads to the emergence of exotic cosmological structures and their hierarchy in energy, temporal, and spatial scale. The mechanism of the formation of physical structures before the Big Bang and their further evolution, up to the formation of worlds of galaxies and stars, is considered. The necessity of the emergence of exotic structures, such as 3 spheres of the Primary Relict, is shown, its structure and dynamic properties leading to the formation of Order from Chaos are considered. The role of the 1st and 2nd type Ether in the formation of the mechanism of transformation of cosmic energies and quantum phase transitions, in the process of the birth and evolution of the Universe is discussed. The conclusion is made about the existence of universal properties of matter, at the level of Macro and Microcosms, and a multidimensional cosmological model with an isothermal temperature distribution is constructed, leading to a discrete distribution of matter separated by transitions, by analogy with Black-and-White Holes. It is shown that the postulate of the constancy of the speed of light in any inertial system is a consequence of the principle of covariance.

相干布居囚禁现象用于原子频标

在Λ型三能级原子系统模型的基础上,采用半经典的密度矩阵方法分析了87Rb气体的相干布居囚禁现象。数值模拟结果显示,当两束相干激光频率差等于87Rb原子的两个基态超精细结构子能级频率差时,87Rb气体具有相干暗线和相干微波辐射的特性。它们可以作为相干布居囚禁原子频标的鉴频物理基础。最后简要分析了两种相干布居囚禁原子频标的各自特点和实验装置结构。

量子微腔中非绝热效应对Fock态制备的影响

利用高阶绝热近似方法，分析了三能级简并原子和单模光场的相互作用过程。

相干布居囚禁原子钟技术及其进展

分析了相干布居囚禁现象的基本原理,介绍了基于相干布居囚禁现象实现的两种原子钟实验装置的原理和结构,分析了各自的特点,并介绍了它们的研究进展以及应用前景。

多能级原子系统暗压缩态的制备

基于二能级原子暗压缩态的制备方案,对多能级原子系统暗压缩态的产生机理进行研究,并提出一个如何在多能级原子系统中制备压缩态的方案。结果表明,在Lamb-Dicke近似下,考虑边带冷却效应就可以将多能级原子冷却至最低最子态;通过选择合适的入射光中心频率,利用多能级原子系统同样可以激光冷却被俘获的原子,并导致暗压缩态的出现。

量子微腔中暗态原子粒子数转移的绝热条件

为了明确量子微腔中粒子数转移的绝热条件，本文利用准绝热近似方法详细地讨论了量子微腔中单模驻波场与简并三能级原子相互作用的动力学演化。

超冷原子向异核四聚物A_2B_2转化的暗态解

提出了超冷原子向异核四聚物分子A2B2转化的理论方案.在平均场近似下,对描述原子-分子转化系统的动力学方程进行解析推导,得出了超冷原子向异核四聚物分子A2B2转化系统的暗态解及其双光子共振条件.该理论结果证实了转化过程的可行性,为实验上进行复杂超冷分子的可控合成提供了重要依据.

一维N能级原子链中的孤波

本文利用实指数方法研究ＤＮＬＳ方程的孤波解，结果发现ＤＮＬＳ方程除了标准的孤子解外。

在原子-腔-光纤系统中制备N个腔模的W态(英文)

提出了一个在原子-腔-光纤系统中制备最大纠缠的W态方案,要求原子与腔之间的耦合常数要比拉比频率小的多。通过暗态绝热演化方法,使原子的自发辐射和光模损耗得到有效抑制。因此一些参数的涨落对此方案的影响比较小。该方案操作比较简便,只要调节原子与腔场之间的耦合系数就能得到W态。此系统构成量子网络的一部分。

超冷原子-分子转化动力学:受激拉曼绝热过程

获得超冷分子是超冷原子分子物理领域的新的热点研究课题。分子具有更多的自由度,能级结构密集、复杂,直接激光冷却存在困难。目前,人们一般借助外场把超冷原子耦合获得超冷分子。受激拉曼绝热通道技术(stimulated Raman adiabatic passage,STIRAP)作为其中一种非常有效地将超冷原子转化为超冷分子的方法已被广泛地研究。该文主要针对STIRAP过程中超冷原子-分子转化系统的动力学,绝热性、稳定性等理论研究的进展进行综述。