Ultra-cold atoms provide ideal platforms for interferometry.The macroscopic matter-wave property of ultra-cold atoms leads to large coherent length and long coherent time,which enable high accuracy and sensitivity to ...Ultra-cold atoms provide ideal platforms for interferometry.The macroscopic matter-wave property of ultra-cold atoms leads to large coherent length and long coherent time,which enable high accuracy and sensitivity to measurement.Here,we review our efforts to improve the performance of the interferometer.We demonstrate a shortcut method for manipulating ultra-cold atoms in an optical lattice.Compared with traditional ones,this shortcut method can reduce the manipulation time by up to three orders of magnitude.We construct a matter-wave Ramsey interferometer for trapped motional quantum states and significantly increase its coherence time by one order of magnitude with an echo technique based on this method.Efforts have also been made to enhance the resolution by multimode scheme.Application of a noise-resilient multi-component interferometer shows that increasing the number of paths could sharpen the peaks in the time-domain interference fringes,which leads to a resolution nearly twice compared with that of a conventional double-path two-mode interferometer.With the shortcut method mentioned above,improvement of the momentum resolution could also be fulfilled,which leads to atomic momentum patterns less than 0.6hkL. To identify and remove systematic noises,we introduce the methods based on the principal component analysis (PCA) that reduce the noise in detection close to the 1/√2 of the photon-shot noise and separate and identify or even eliminate noises.Furthermore,we give a proposal to measure precisely the local gravity acceleration within a few centimeters based on our study of ultracold atoms in precision measurements.展开更多
We simulate ultra-cold interacting bosons in quasi-one-dimensional, incommensurate optical lattices. In the tight-binding limit, these lattices have pseudo-random on-site energies and thus can potentially lead to Ande...We simulate ultra-cold interacting bosons in quasi-one-dimensional, incommensurate optical lattices. In the tight-binding limit, these lattices have pseudo-random on-site energies and thus can potentially lead to Anderson localization. We use the Hartree-Fock-Bogoliubov formalism in the Bose-Hubbard model to explore the parameter regimes that lead to exponential localization of the ground state in a 3-colour optical lattice and investigate the role of repulsive interactions, harmonic confinement and finite temperature.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2016YFA0301501)the National Natural Science Foundation of China(Grant Nos.61727819,11934002,91736208,and 11920101004)the Project funded by China Postdoctoral Science Foundation(Grant No.2020TQ0017)。
文摘Ultra-cold atoms provide ideal platforms for interferometry.The macroscopic matter-wave property of ultra-cold atoms leads to large coherent length and long coherent time,which enable high accuracy and sensitivity to measurement.Here,we review our efforts to improve the performance of the interferometer.We demonstrate a shortcut method for manipulating ultra-cold atoms in an optical lattice.Compared with traditional ones,this shortcut method can reduce the manipulation time by up to three orders of magnitude.We construct a matter-wave Ramsey interferometer for trapped motional quantum states and significantly increase its coherence time by one order of magnitude with an echo technique based on this method.Efforts have also been made to enhance the resolution by multimode scheme.Application of a noise-resilient multi-component interferometer shows that increasing the number of paths could sharpen the peaks in the time-domain interference fringes,which leads to a resolution nearly twice compared with that of a conventional double-path two-mode interferometer.With the shortcut method mentioned above,improvement of the momentum resolution could also be fulfilled,which leads to atomic momentum patterns less than 0.6hkL. To identify and remove systematic noises,we introduce the methods based on the principal component analysis (PCA) that reduce the noise in detection close to the 1/√2 of the photon-shot noise and separate and identify or even eliminate noises.Furthermore,we give a proposal to measure precisely the local gravity acceleration within a few centimeters based on our study of ultracold atoms in precision measurements.
基金supported by contract SFB/TR 12 of the German Research Foundation and through the IB BMBF(Project NZL 07/006)by the New Zealand Foundation for Research,Science and Technology through contract NERF-UOOX0703:Quantum Technologies and the New Zealand International Science and Technology Linkages FundJT and DAWH also acknowledge support from the National Research Foundation and Ministry of Education of Singapor.
文摘We simulate ultra-cold interacting bosons in quasi-one-dimensional, incommensurate optical lattices. In the tight-binding limit, these lattices have pseudo-random on-site energies and thus can potentially lead to Anderson localization. We use the Hartree-Fock-Bogoliubov formalism in the Bose-Hubbard model to explore the parameter regimes that lead to exponential localization of the ground state in a 3-colour optical lattice and investigate the role of repulsive interactions, harmonic confinement and finite temperature.
文摘选取HC700/980DHD+Z、 HC780/980CPD+Z和HC700/980DPD+Z进行分析,对比了3种材料力学性能和极限冷弯性能的差异;基于5种硬化模型对材料性能曲线进行拟合,选取两类拟合度较高的模型构建了组合硬化模型,并采用R5缺口拉伸试验进行了验证;基于前防撞梁静态三点弯曲测试和仿真对标分析,对组合硬化模型进行验证,并对3种材料的承载性能进行对比分析。结果表明:HC700/980DHD+Z和HC780/980CPD+Z的极限冷弯角分别为109.8°和109.6°,优于HC700/980DPD+Z;前纵梁静态三点弯曲试验测试与仿真分析中关键参数的最大误差在6%左右,表明材料本构模型的精度较高;HC780/980CPD+Z的承载力峰值最大,达到15.1 k N;HC700/980DHD+Z达到承载力峰值的位移最大,达到52 mm;屈强比对静态承载过程的峰值力产生重要影响,而断后伸长率的增加提升了材料的强塑积和塑性应变变形,使得承载力峰值的位移增大。
