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We investigate the energy spectrum of fermionized bosonic atoms, which behave very much like spinless noninteracting fermions, in optical lattices by means of the perturbation expansion and the retarded Green's function method. The results show that the energy spectrum splits into two energy bands with single-occupation; the fermionized bosonic atom occupies nonvanishing energy state and left hole has a vanishing energy at any given momentum, and the system is in Mott-insulating state with a energy gap. Using the characteristic of energy spectra we obtained a criterion with which one can judge whether the Tonks-Girardeau (TG) gas is achieved or not. 相似文献
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聚甲基丙烯酸—对—甲氧基偶氮苯烷氧基酯的合成及柔性间隔基对液晶?… 总被引:2,自引:0,他引:2
通过甲基丙烯酸钾盐与溴化物的反应合成了一系列柔性间隔基长度不同的甲基丙烯酸-对-甲氧基偶氮苯烷氧基酯(PMAAZOn,n=2,3,4,5,6)然后聚合成相应的聚合物,用H-NMR和IR表征了聚合物的结构,GPC测定了分子量,DSC和偏江显微观测了液晶高分子的相行为和织构,研究了间隔基长度对织构、相变和热力学性质的影响,观测到聚合物的TNI随间隔基的长度变化表现出的奇偶效应。 相似文献
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We report an experimental demonstration of a new scheme to split cold atoms on an atom chip. The atom chip consists of a U-wire and a Z-wire. The cold atom cloud is initially loaded and prepared in the Z-trap, which is split into two separate parts by switching on the current of the U-wire. The two separate atom clouds have a distance more than one millimeter apart from each other and show almost symmetrical profiles, corresponding to about a 50/50 splitting ratio. 相似文献
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We demonstrate the direct loading of cold atoms into a microchip 2-mm Z-trap, where the evaporative cooling can be performed efficiently, from a macroscopic quadrupole magnetic trap with a high loading efficiency. The macroscopic quadrupole magnetic trap potential is designed to be moveable by controlling the currents of the two pairs of anti-Helmholtz coils. The cold atoms are initially prepared in a standard six-beam magneto-optical trap and loaded into the macroscopic quadrupole magnetic trap, and then transported to the atom chip surface by moving the macroscopic trap potential. By means of a three-dimensional absorption imaging system, we are able to optimize the position alignment of the atom cloud in the macroscopic trap and the microchip Z-shaped wire. Consequently, with a proper magnetic transfer scheme, we load the cold atoms into the microchip Z-trap directly and efficiently. The loading efficiency is measured to be about 50%.This approach can be used to generate appropriate ultracold atoms sources, for example, for a magnetically guided atom interferometer based on atom chip. 相似文献
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基于光诱导的原子脱附技术,采用脉冲紫外光剥离出玻璃池壁上吸附的铷原子以形成可快速开启和关断的脉冲铷原子源,成功地解决了单真空腔系统中磁阱的原子数和寿命之间的矛盾,突破了激光冷却和囚禁技术向小型化乃至微型化发展过程中的一个瓶颈.脉冲光源由390nm的LED阵列组成.实验结果表明它能够在1s内使真空铷原子气体分压提高近30倍,并且当紫外光关闭后系统的真空恢复到平衡状态的时间非常短,约120ms.测量了不同铷原子分压下磁光阱所俘获的最大原子数和装载时间,并由此得出系统的背景真空和磁光阱所能俘获的极限原子数,进一步得出磁阱的原子数-寿命积与磁光阱保持阶段时间的变化关系,结果显示在约1.25s处出现极大值,与无磁光阱保持阶段而直接进行磁阱装载情况相比提高了约0.3倍.
关键词:
激光冷却
磁光阱
光诱导原子脱附
原子数-寿命积 相似文献
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提出了加速溶剂萃取-气相色谱-质谱法测定塑料中15种致敏芳香化合物。样品与硅藻土混匀后采用丙酮为溶剂,在80℃,1 500 MPa压力条件下提取20min,循环2次,萃取物浓缩定容后经DB-17石英毛细管色谱柱分离,在全扫描和选择离子监测模式下测定。颜色较深的样品经硅胶固相萃取小柱净化后测定,内标法定量。15种化合物的线性范围均为0.005~60 mg·L-1,检出限(3S/N)在0.005~0.03mg·L-1之间。方法用于聚丙烯、聚乙烯、丙烯腈-丁二烯-苯乙烯塑料样品的分析,加标回收率在83.3%~118%之间,测定值的相对标准偏差(n=5)在3.0%~9.9%之间。 相似文献
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