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Controlling the amplitude of soliton in a growing Bose-Einstein condensate by means of feshbach resonance

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Chinese Physics B 2008年第10期17卷 3640-3643页

作者：何章明王登龙张蔚曦王凤姣丁建文 Department of Physics and Key Laboratory of Low Dimensional Materials & Application Technology of Ministry of Education Xiangtan University

By using Darboux transformation, this paper studies analytically the nonlinear dynamics of a one-dimensional growing Bose-Einstein condensate （BEC）. It is shown that the growing model has an important effect on the amplitude of the soliton in the condensates. In the absence of the growing model, there exhibits the stable alternate bright solitons in the condensates. In the presence of the growing model, the obtained results show that the amplitude of the bright soliton decreases （increases） for the BEC growing coefficient Ω 〈 0 （Ω 〉 0）. Furthermore, we propose experimental protocols to manipulate the amplitude of the bright soliton by varying the scattering length via the feshbach resonance in the future experiment.

关键词： feshbach resonance Bose-Einstein condensate bright soliton

Dynamics of Bose-Einstein condensates near feshbach resonance in external potential

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Frontiers of physics 2011年第1期6卷 46-60页

作者：张晓斐胡兴华王灯山刘循序刘伍明 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China College of Science Honghe University Mengzi 661100 China

We review our recent theoretical advances in the dynamics of Bose Einstein condensates with tunable interactions using feshbach resonance and external potential. A set of analytic and numerical methods for Gross Pitaevskii equations are developed to study the nonlinear dynamics of BoseEinstein condensates. Analytically, we present the integrable conditions for the Gross Pitaevskii equations with tunable interactions and external potential, and obtain a family of exact analytical solutions for one- and two-component Bose Einstein condensates in one and two-dimensional cases. Then we apply these models to investigate the dynamics of solitons and collisions between two solitons. Numerically, the stability of the analytic exact solutions are checked and the phenomena, such as the dynamics and modulation of the ring dark soliton and vector-soliton, soliton conversion via feshbach resonance, quantized soliton and vortex in quasi-two-dimensional are also investigated. Both the exact and numerical solutions show that the dynamics of Bose Einstein condensates can be effectively controlled by the feshbach resonance and external potential, which offer a good opportunity for manipulation of atomic matter waves and nonlinear excitations in Bose Einstein condensates.

关键词： Bose Einstein condensate feshbach resonance soliton

Photonic feshbach resonance

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Science China(Physics,Mechanics & Astronomy) 2010年第7期53卷 1234-1238页

作者： XU DaZhi IAN Hou SHI Tao DONG Hui SUN ChangPu Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

feshbach resonance is a resonance for two-atom scattering with two or more channels,in which a bound state is achieved in one *** show that this resonance phenomenon not only exists during the collisions of massive particles,but also emerges during the coherent transport of massless particles,that is,photons confined in the coupled resonator arrays linked by a separated cavity or a tunable two level system(TLS).When the TLS is coupled to one array to form a bound state in this setup,the vanishing transmission appears to display the photonic feshbach *** process can be realized through various experimentally feasible solid state systems,such as the couple defected cavities in photonic crystals and the superconducting qubit coupled to the transmission *** numerical simulation based on the finite-different time-domain(FDTD) method confirms our assumption about the physical implementation.

关键词： feshbach resonance bound state single-photon transistor

Two-color laser modulation of magnetic feshbach resonances

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Chinese Physics B 2015年第8期24卷 203-207页

作者：李健刘勇黄寅丛书林 School of Physics and Optoelectronic Technology Dalian University of Technology

We investigate the two-color laser modulation of the magnetically induced feshbach resonance. The two-color laser is nearly resonant with an optical bound-to-bound transition at the resonance position. The analytical formula of scattering length is obtained by solving the Heisenberg equation. The scattering length can be modified by changing the Rabi frequencies or optical field frequency. By choosing the suitable optical parameters, the two-body loss coefficient K2 can be greatly reduced compared to the usual single optical scheme.

关键词： ultracold molecule feshbach resonance two-body loss coefficient

Electric-field-modified feshbach resonances in ultracold atom–molecule collision

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Chinese Physics B 2017年第1期26卷 182-186页

作者： Dong Cheng Ya Li Eryin Feng Wuying Huang Department of Physics Anhui Normal University. Wuhu 241000 China

We present a detailed analysis of near zero-energy feshbach resonances in ultracold collisions of atom and molecule,taking the He–PH system as an example, subject to superimposed electric and magnetic static fields. We find that the electric field can induce feshbach resonance which cannot occur when only a magnetic field is applied, through couplings of the adjacent rotational states of different parities. We show that the electric field can shift the position of the magnetic feshbach resonance, and change the amplitude of resonance significantly. Finally, we demonstrate that, for narrow magnetic feshbach resonance as in most cases of ultracold atom–molecule collision, the electric field may be used to modulate the resonance, because the width of resonance in electric field scale is relatively larger than that in magnetic field scale.

关键词： feshbach resonance ultracold atom–molecule collision

Radio-frequency spectroscopic measurement for pairing gap in an ultracold Fermi gas

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Science China(Physics,Mechanics & Astronomy) 2013年第3期56卷 581-587页

作者： JIANG KaiJun LUO Hua LI Kai ZHANG DongFang GAO TianYou PENG ShiGuo State Key Laboratory of Magnetic resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsChinese Academy of Sciences

The study of ultracold Fermi gases has exploded a variety of experimental and theoretical research since the achievement of degenerate quantum gases in the lab,which expands the research range over atomic physics,condensed matter physics,astrophysics and particle *** the feshbach resonance,one can tune the attractive two-body interaction from weak to strong and thereby make a smooth crossover from the BCS superfluid of cooper pairs to the Bose Einstein condensate of bound *** this crossover regime,the pairing effect plays a significant role in interpreting the interaction *** the localized or delocalized pairing occurs at sufficiently low temperature,the single-particle energy will shift with respect to free atoms,due to the two-body or many-body *** the pairing gap can improve the understanding of the thermodynamics and hydrodynamics of the phase transition from the pseudogap to the superfluid,which will make an analogue to the high-temperature superconductivity in condensed *** this work,we will give a brief introduction to a novel radio-frequency(RF) spectroscopic measurement for pairing gap in an ultracold Fermi gas,which is currently widely used on the ultracold atomic table in the *** different interaction regimes of the BEC-BCS crossover,ultracold atoms are excited with a RF pulse and the characteristic behavior can be extracted from the spectrum.

关键词： degenerate Fermi gas feshbach resonance Bose Einstein condensate superfluid

Radio-frequency spectroscopy of weakly bound molecules in ultracold Fermi gas

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Chinese Physics B 2014年第1期23卷 211-214页

作者：黄良辉王鹏军付正坤张靖 State Key Laboratory of Quantum Optics and Quantum Devices Institute of Opto-Electronics Shanxi University Taiyuan 030006 China

We create weakly bound feshbach molecules in ultracold Fermi gas40K by sweeping a magnetic field across a broad feshbach resonance point 202.2 G with a rate of 20 ms/G and perform the dissociation process using radio-frequency(RF) technology. From RF spectroscopy, we obtain the binding energy of the weakly bound molecules in the vicinity of feshbach resonance. Our measurement also shows that the number of atoms generated from the dissociation process is different at various magnetic fields with the same RF amplitude, which gives us a deeper understanding of weakly bound feshbach molecules.

关键词： feshbach resonance scattering length weakly bound molecules

Production of an ultracold mixture of ^(23)Na^(40)K and ^(40)K

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Science China(Physics,Mechanics & Astronomy) 2022年第2期65卷 39-43页

作者： Xin-Yao Wang Zhen Su Jin Cao Huan Yang Bo Zhao Chun-Li Bai Jian-Wei Pan Beijing National Laboratory for Molecular Sciences Key Laboratory of Molecular Nanostructure and NanotechnologyCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China Hefei National Laboratory for Physical Sciences at the Microscale and Department 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 A Shanghai Research Center for Quantum Sciences Shanghai 201315China University of Chinese Academy of Sciences Beijing 100049China

We report on the production of an ultracold mixture of 2.8×10^(4)^(23)Na^(40)K molecules and 3.3×10^(5)^(40)K atoms at a temperature of about 250 n *** with previous studies,the number of atoms and molecules improved by a factor of about 2,and the temperature reduced by a factor of about *** improvements occur mainly because of the use of a crossed large-volume horizontal dipole trap to load the atoms from a cloverleaf-type magnetic trap,and a large-volume three-beam dipole trap to perform optical evaporative *** achieving the mode-matching loading,this method avoids evaporative cooling in a decompressed cloverleaf magnetic trap,which is sensitive to magnetic field *** characterize an atom-molecule feshbach resonance using the ultracold atom-molecule *** enhancement of particle number and temperature significantly improves the signal-to-noise ratio,and enables us to refine the location and width of the feshbach resonance.

关键词： ultracold molecule Bose-Fermi mixture feshbach resonance

Energy Spectrum of a Degenerate Fermi Gas at the BEC-BCS Crossover

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Communications in Theoretical Physics 2007年第5X期48卷 855-858页

作者： FANG Yuan Beijing National Laboratory for Condensed Matter Physics Institute of Physics the Chinese Academy of Sciences Beijing 100080 China

A theoretical study of the BCS-BEC crossover is presented. Starting from a two-channel Boson-Fermion resonance model, the BCS-Bogoiubov mean-field method and the Green＇s function method are adopted. The result shows that we can end up with a BCS-type theory but with a composite order parameter. Calculation shows that the Bose condensate of BCS Cooper pairs is proportional to the molecular BEC of Bose molecules. The resonance superfluid phase is indicated by the energy spectrum with an obvious interpretation of the transition mechanism.

关键词： degenerate Fermi gas BEC-BCS crossover feshbach resonance