Collective Excitations and Nonlinear Dynamics of 1D BEC with Two- and Three-body Interactions in Anharmonic Traps

The collective excitations of low-dimensional Bose-Einstein condensates with two- and three-body interactions in anharmonic potentials are investigated. Using the standard variational approach, the governing equations of motions for the low-energy excitations are obtained by solving time-dependent Gross-Pitaevskii-Ginzburg equation, and the excitation spectrums are calculated in small amplitude limit. The frequency shift and nonlinear mode coupling induced by the anharmonic distortion （adding cubic, quartic, or quintic terra to a harmonic trap） are studied.     

Collective Band Structures and Identification of One-Phonon and Two-Phonon γ-Vibrational Bands in 109Tc

The high spin states of the neutron-rich 109Tc nucleus are reinvestigated by observing prompt γ-rays from the spontaneous fission of 252 Cf. The previously known yrast band based on the 7/2＋ state is updated. A side band built on the 11/2＋ state is expanded and a new band based on the 15/2＋ state is identified. Band crossing in the yrast band occurs around fω≈ 0.36 MeV. This band crossing is associated with the alignment of two h11/2 neutrons according to the cranked shell model calculations. The band based on the 11/2＋ state is proposed as a candidate for the one-phonon γ-vibrational band, and the band built on the 15/2＋ state is proposed as a candidate for the two-phonon γ-vibrational band. Other characteristics for the observed bands are discussed.     

Bose--Einstein Condensates with Two- and Three-Body Interactions in an Anharmonic Trap at Finite Temperature

The transition temperature, the depletion of the condensate atoms and the collective excitations of a Bose-Einstein condensation （BEC） with two- and three-body interactions in an anharmonic trap at finite temperature are studied in detail. By using the Popov version of the Hartree-Fock-Bogoliubov （HFB） approximation, an extended self-consistent model describing BEC with both two- and three-body interactions in a distorted harmonic potential at finite temperature is obtained and solved numerically. The results show that the transition temperature, the condensed atom number and the collective excitations are modified dramatically by the atomic three-body interactions and the distortion of the harmonic trap.     

BCS-BEC渡越过程超流费米气体在线性变化势中的集体激发

基于超流流体力学方程组和标度理论,数值研究了Bardeen-Cooper-Schrieffer (BCS)-Bose-Einstein Condensate (BEC)渡越过程中超流费米气体在线性减小谐振子势下的集体激发.详细研究了包括谐振子势频率线性减小的速度,减小到的幅度以及势阱各向异性参数对集体激发的影响.通过频谱分析和数据拟合,分别研究了各向同性势和各向异性势下在最小振幅激发下所对应的模式,且数值计算得到的频率值在整个BCS-BEC渡越过程中与前期的理论结果符合得很好.该工作可以为后面超流费米气体集体激发的实验提供有益的理论参考     

精设数学活动 渗透数学思想——“减8的退位减”备课思路

<正>《义务教育数学课程标准(2022年版)》指出,课程内容要反映社会的需要及数学的特点,要符合学生的认知规律,它不仅包括数学的结果,也包括数学结果的形成和蕴含的数学思想方法。珠心算教育实验的主体大都是低年级儿童,年龄特征与知识积累情况提醒我们,在教学中要用心设计数学活动,适时渗透数学思想方法。持之以恒坚持下去,这些数学思想和方法将在较长的认知过程中被学生逐步理解和掌握,使学生具有用数学的眼光观察事物、分析问题、解决问题的能力。     

细胞骨架微管中水分子Kerr效应对电磁场辐射的影响

微管是细胞骨架的主要组成成分和功能组件,其中充满了属于Kerr介质的液体水。本文运用量子场论路径积分方法,研究微管中水分子与电磁场的相互作用。为了考虑Kerr效应,在系统的哈密顿量中引入电磁场的非谐项。我们给出了含有Kerr非线性项的电磁辐射运动方程,进而讨论了Kerr效应对电偶极子集体辐射的影响。     

火焰原子吸收分光光度法测定浸渍活性炭中银含量

浸渍活性炭是一种浸渍有铜、铬、银的化学战剂主要吸附剂,主要用于各种军用滤毒罐和集体防护器材的关键装填材料,是依靠活性炭的物理吸附和浸渍活性炭的化学吸着作用以及催化吸着作用来净化染毒空气的.     

冷原子吸收光谱法测定儿童首饰中可溶性镉

研究了儿童首饰中可溶性镉的冷原子化反应体系。在酸性介质中,用硼氢化钠将镉离子还原为镉原子,用载气将镉蒸气导入石英管,原子吸收分光光度计在波长228.8 nm处进行测定。对载气流速、NaBH4浓度、增敏剂加入量和介质酸度的影响，以及共存离子的干扰进行了研究。方法简便快速，在优化的实验条件下，方法的检出限为0.05 mg/kg。加标回收率为98.3％～103.1％，相对标准偏差小于2.2%。该方法具有快速、准确、灵敏度高、经济实用等优点，用于儿童首饰中痕量镉的测定，结果令人满意。     

超级里德伯原子间的稳态关联集体激发与量子纠缠

处于同一偶极阻塞区域的里德伯原子系综可以看作一个超级原子,如果它们被捕获在两个不同的光偶极阱中,那么每一个光偶极阱中的子原子系综可以看作为一个亚超级原子.由于这两个亚超级原子共享不超过一个激发的里德伯原子,所以它们会强烈地关联起来.本文研究这两个里德伯亚超级原子的稳态关联集体激发特性和量子纠缠行为.结果表明原子数目带来的影响非常明显:里德伯亚超级原子越大(包含原子数目越多),集体激发概率越大;最大纠缠只发生在等大的两个里德伯亚超级原子之间.通过增加原子数目,可以实现介观领域的量子纠缠,对量子-经典对应的研究以及量子信息处理有着重要的作用.     

充分发挥物理学史的集体意识培育功能

培养中学生的集体意识是中学物理课堂的德育功能之一.从科学本质视角，通过合理有机地组织和展示具体的物理学史，并避免使用“个人化”特征的语言，强调集体对于物理学探索和物理学家个人的作用，让学生体会物理学探索的曲折性、经验性和批判性、统一性和未完成性，意识到集体力量的巨大作用和不可或缺，达到培养集体意识的目的.