Vortices in superfluid fermi gases through the BEC to BCS crossover

We have analyzed a single vortex at T=0 in a 3D superfluid atomic Fermi gas across a Feshbach resonance. On the BCS side, the order parameter varies on two scales: k(F)(-1)and the coherence length xi, while only variation on the scale of xi is seen away from the BCS limit. The circulating current has a peak value jmax which is a nonmonotonic function of 1/k(F)a(s) implying a maximum critical velocity approximately v(F) at unitarity. The number of fermionic bound states in the core decreases as we move from the BCS to the BEC regime. Remarkably, a bound state branch persists even on the BEC side reflecting the composite nature of bosonic molecules.     

Metrological orientation-confirmation of Si(h h k) using scanning tunneling microscopy

For the periodicity-modulation of the Si(h h k) template between (0 0 1) and (1 1 1), it is necessary to prepare the surface with any orientation within this range, most especially for fabricating useful one-dimensional nanostructures. Especially, when there are no strong X-ray signals using the standard Cu K-α source in the vicinity of any arbitrarily chosen (H H K), it turns out that the line-profile analysis on the topographic image of scanning tunneling microscopy can be a unique way for confirming the orientation of the prepared surface. Though there are a number of small-width facets on the reconstructed surface, if any of well-defined facets, such as (1 1 1), (3 3 7), (1 1 2), and (3 3 5), are included in these facets it is possible to determine the orientation using the weighted-average method.     

Bound states and dipole polarizability of hydrogen molecular ion H2 in weakly coupled hot plasmas

The effects of hot-dense plasmas on the bound states and the dipole polarizability of the ground state of Coulomb three-body molecular ion H⁺₂ have been investigated using highly correlated basis functions and by considering the Debye shielding approach of plasma modeling. The ground S state and the first excited P state energies along with the dipole polarizability for different shielding parameters are reported.     

Deconfinement in a 2D optical lattice of coupled 1D boson systems

We show that a two-dimensional (2D) array of 1D interacting boson tubes has a deconfinement transition between a 1D Mott insulator and a 3D superfluid for commensurate fillings and a dimensional crossover for the incommensurate case. We determine the phase diagram and excitations of this system and discuss the consequences for Bose condensates loaded in 2D optical lattices.     

Random coil phosphorus chemical shift of deoxyribonucleic acids

Random coil phosphorus chemical shift has been studied using 16 17-nucleotide DNA sequences. Due to the presence of residual base stacking in these sequences, the temperature and sequence effects were investigated at 50 and 55 degrees C. The phosphorus chemical shifts of random coil DNA sequences have been found to be independent of temperature. Sequence effect analysis shows that the phosphorus chemical shift of a nucleotide in a random coil DNA sequence depends on both its 5'- and 3'-nearest neighbors. A trimer model has been used to establish the random coil 31P chemical shift prediction protocol which shows an accuracy of 0.02 ppm.     

Short-Range Inverse-Square Law Experiment in Space

The objective of ISLES (Inverse-Square Law Experiment in Space) is to perform a null test of Newton's law in space with a resolution of one part in 10⁵ or better at 100 m. ISLES will be sensitive enough to detect axions with the strongest allowed coupling and probe large extra dimensions of string theory down to a few m. The experiment will be cooled to 2 K, which permits superconducting magnetic levitation of the test masses. This soft, low-loss suspension, combined with a low-noise SQUID, leads to extremely low intrinsic noise in the detector. To minimize Newtonian errors, ISLES employs a near null source, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are suspended on the two sides of the source mass at a nominal distance of 100 m. The signal is detected by a superconducting differential accelerometer.     

用于脉冲γ强度测量的Ф60,1000μmPIN探测器

采用电阻率为10000—20000Ω.cm的高阻单晶硅材料,研制成功灵敏区尺寸为60mm,耗尽层厚度~1000μm的大面积厚PIN半导体探测器.设计了该类探测器厚度测量专用的反冲质子测量系统,对探测器的时间响应、γ灵敏度、漏电流、γ/n分辨等物理参数进行了测量和分析,结果表明,这类探测器可满足低强度裂变n/γ混合场中脉冲γ强度测量的需要.     

High‐energy‐resolution diced spherical quartz analyzers for resonant inelastic X‐ray scattering

A novel diced spherical quartz analyzer for use in resonant inelastic X‐ray scattering (RIXS) is introduced, achieving an unprecedented energy resolution of 10.53 meV at the Ir L₃ absorption edge (11.215 keV). In this work the fabrication process and the characterization of the analyzer are presented, and an example of a RIXS spectrum of magnetic excitations in a Sr₃Ir₂O₇ sample is shown.