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Research on ultracold cesium molecule long-range states by high-resolution photoassociative spectroscopy

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Science China(Physics,Mechanics & Astronomy) 2008年第2期51卷 147-156页

作者： WANG LiRong MA Jie JI WeiBang WANG GuiPing XIAO LianTuan JIA SuoTang State Key Laboratory of Quantum Optics and Quantum Optics Devices College of Physics and Electronics EngineeringShanxi UniversityTaiyuan 030006China

In this paper, an ultra-high resolution photoassociation spectroscopy study on photoassociation of cesium atoms is reported. The cold cesium gas in the mag-neto-optical trap is illuminated by a photoassociation laser with red-tuning as large as 40 cm?1 below the 6S1/2 + 6P3/2 dissociation limit, and the photoassociation to the excited state ultracold molecule is detected. High signal-to-noise ratio is obtained by using the lock-in detection of the fluorescence from the modulated cold Cs at-oms. The 0g?, 1g and 0u+ long-range states which correspond to 6S1/2 + 6P3/2 dissocia-tion limit are present in the photoassociation spectrum. The effective coefficients of leading long-range interactions and the corresponding vibrational quantum num-ber are obtained using LeRoy-Bernstein Law. It is found that photoassociation process creates rotating molecules and the high J value is a hint that higher partial waves participate in the PA process in the presence of trapping laser.

关键词： ultracold molecule photoassociation high-resolution spectrum

Light-induced frequency shifts for the lowest vibrational levels of ultracold Cs2 in the molecular pure long-range 0^-g state

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Frontiers of physics 2020年第2期15卷 57-62页

作者： Ji-Zhou Wu Yu-Qing Li Wen-Liang Liu Jie Ma Lian-Tuan Xiao Suo-Tang Jia State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi UniversityTaiyuan 030006China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China College of Physics and Electronic Engineering Shanxi UniversityTaiyuan 030006China

The light-induced frequency shift(LIFS)of ultracold molecular ro-vibrational levels originates from the strong coupling of the atomic-scattering state and the bound-molecular state.In this paper,we present our experimental determination of the LIFSs of the lowest vibrational levels(v=0,1)in the purely long-range 0^-g state of ultracold cesium molecules.A high-resolution double photoassociation spectroscopy is developed,which serves as frequency ruler to measure the frequency shifts of the lowest molecular levels for Cs2.The experimental results are qualitatively consistent with the theoretical expectations.

关键词： light-induced frequency shift ultracold molecule double photoassociation spectroscopy long-range state

Effect of external magnetic field on the shift of resonant frequency in photoassociation of ultracold Cs atoms

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Chinese Physics B 2019年第1期28卷 367-371页

作者：李鹏伟李玉清冯国胜武寄洲马杰肖连团贾锁堂 State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyCollege of Physics and Electronics Engineering Shanxi University Collaborative Innovation Center of Extreme Optics Shanxi University

We study the influence of external magnetic field on the shift of the resonant frequency in the photoassociation of ultracold Cs atoms, which are captured in a magnetically levitated optical crossed dipole trap. With the increase of the photoassociation laser intensity, the linear variation of the frequency shift is measured by recording the photoassociation spectra of the long-range 0_u^+ state of Cs molecule below the 6S_(1/2)+ 6P_(1/2) dissociation limit at different magnetic fields.The slope of the frequency shift to the intensity of the photoassociation laser exhibits a strong dependence on the external magnetic field. The experimental data is simulated with an analytic theory model, in which a single channel rectangular potential with the tunable well depth is introduced to acquire the influence of the magnetic field on the atomic behavior in the effective range where photoassociation occurs.

关键词： ultracold molecule photoassociation frequency shift

Phase Time for the Tunneling of ultracold V-Type Atoms Through a Mazer Cavity

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Communications in Theoretical Physics 2019年第5期71卷 610-616页

作者： Fazal Badshah Abdul Basit Hamad Ali Qing He Guo-Qin Ge School of Physics Huazhong University of Science and Technology Quantum Optics Lab.Department of Physics COMSATS University Islamabad College of Science Zhongyuan University of Technology

We study the tunneling time of ultracold V-type atoms interacting a high quality microwave cavity. Here atomic coherence is introduced in the system by a strong driving field which couples the two lower states of the three-level atom. It is found that in the presence of coherence, mazer action or the scattering like nature of the interaction may be examined for extended energies of the incident cold atoms. Our results show that position and amplitudes of the peak values of the phase time(traversal time) may be very effectively controlled by the coherent driving field. Further, here we obtained superclassical values of the phase time corresponding to much higher values of the transmission amplitudes of the tunneling atoms which may be advantageous in the possible experimental realization of the superclassical tunneling time of the traversing cold atoms. In addition, we examine a mirror reflection type symmetry in the phase time curve for a judicious choice of the external driving field.

关键词： ultracold atoms mazer cavity phase time superclassicality

Dynamical classification of topological quantum phases

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Science Bulletin 2018年第21期63卷 1385-1391页

作者： Lin Zhang Long Zhang Sen Niu Xiong-Jun Liu International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and TechnologyShenzhen 518055China

Topological phase of matter is now a mainstream of research in condensed matter physics, of which the classification, synthesis, and detection of topological states have brought excitements over the recent decade while remain incomplete with ongoing challenges in both theory and experiment. Here we propose to establish a universal non-equilibrium characterization of the equilibrium topological quantum phases classified by integers, and further propose the high-precision dynamical schemes to detect such states. The framework of the dynamical classification theory consists of basic theorems. First, we uncover that classifying a d-dimensional(dD) gapped topological phase of generic multibands can reduce to a(d-1)D invariant defined on so-called band inversion surfaces(BISs), rendering a bulk-surface duality which simplifies the topological characterization. Further, we show in quenching across phase boundary the(pseudo) spin dynamics to exhibit unique topological patterns on BISs, which are attributed to the post-quench bulk topology and manifest a dynamical bulk-surface correspondence. For this the topological phase is classified by a dynamical topological invariant measured from an emergent dynamical spintexture field on the BISs. Applications to quenching experiments on feasible models are proposed and studied, demonstrating the new experimental strategies to detect topological phases with high feasibility. This work opens a broad new direction to classify and detect topological phases by non-equilibrium quantum dynamics.

关键词： Quench dynamics Topological quantum phase Band inversion surface Bulk-surface duality Dynamical topological invariant ultracold atoms Synthetic gauge field

Analytical Solution for an ultracold Trapped Ion at the Node of the Standing Wave Laser Without Rotating Wave Approximation

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Communications in Theoretical Physics 2001年第11期36卷 597-600页

作者： FANG Xi-Ming FENG Mang Department of Physics Hunan Normal UniversityChangsha 410081China Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsWuhan Institute of PhysicsAcademia SinicaWuhan 430071China

A method of solving an ultracold trapped ion at the node of the standing wave laser without rotating wave approximation is proposed and the analytical forms of the eigenfunctions and eigenenergies of the system are pr... 详细信息

关键词： ultracold trapped ion,analytical solution,rotating wave approximation

Magnetically tunable atom-exchange process involving ultracold weakly bound Feshbach molecules

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Science China(Physics,Mechanics & Astronomy) 2020年第5期63卷 31-38页

作者： Jue Nan Bo Zhao Hefei National Laboratory for Physical Sciences at Microscale and Deparment of Modern Physics University of Science and Technology of ChinaHefei 230026China Shanghai Branch CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum PhysicsUniversity of Science and Technology of ChinaShanghai 201315China

Chemical reactions at ultracold temperatures have attracted great interest in recent years. The atom-exchange reaction between an atom and a weakly bound Feshbach molecule near overlapping Feshbach resonances presents a simple and ideal example of the controlled ultracold chemistry. The energy released in the reaction can be tuned to be very small and thus the reaction products can be trapped and detected, allowing the study of state-to-state reaction dynamics. The reaction can be tuned from the exothermic regime to the endothermic regime, which allows to study the threshold behavior of an endothermic reaction. In this paper, we review the recent progress in studying the atom-exchange reaction involving Feshbach molecules in ultracold atomic gases.

关键词： Feshbach molecule atom-exchange process ultracold collision

Topological gapless matters in three-dimensional ultracold atomic gases

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Frontiers of physics 2019年第4期14卷 21-46页

作者： Yong Xu Center for Quantum Information IIIS Tsinghua University Beijing 100084 China

Three-dimensional topological gapless matters with gapless degeneracies protected by a topological invariant defined over a closed manifold in momentum space have attracted considerable interest in various fields ranging from condensed matter materials to ultracold atomic gases. As a highly controllable and disorder free system, ultracold atomic gases provide a versatile platform to simulate topological gapless matters. Here, the current progress in studies of topological gapless phenomena in three-dimensional cold atom systems is summarized in the review. It is mainly focused on Weyl points, structured (type-Ⅱ) Weyl points, Dirac points, nodal rings and Weyl exceptional rings in cold atoms. Since interactions in cold atoms can be controlled via Feshbach resonances, the progress in both superfluids for attractive interactions and non-interacting cold atom gases is reviewed.

关键词： ultracold atomic gases Weyl points Dirac points nodal rings Weyl exceptional rings

An introduction to dressed-atom adiabatic potentials for ultracold atoms

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Instrumentation 2015年第4期2卷 76-84页

作者： Tiffany Harte Elliot Bentine Edward Owen XU Dongyang Benjamin Yuen Christopher Foot Clarendon Laboratory University of Oxford

We give a simple introduction to the theoretical treatment of atoms interacting strongly w ith electromagnetic fields in the radiofrequency,microw ave and laser domains. In particular,w e discuss the concept of dressed atoms,w hich considers the combination of the atom and photons as a composite physical system. This pow erful concept has a w ide range of applications in atomic physics and w e give a few examples of its use in the manipulation of ultracold atoms in adiabatic potentials. These examples are selected from experimental w ork conducted by our research team in Oxford but there are numerous other applications and w e outline some future possibilities.

关键词： ultracold atoms dressed potentials