Laser frequency combs and ultracold neutrons to probe braneworlds through induced matter swapping between branes

This paper investigates a new experimental framework to test the braneworld hypothesis. Recent theoretical results have shown the possibility of matter exchange between branes under the influence of suitable magnetic vector potentials. It is shown that the required conditions might be achieved with present-day technology. The experiment uses a source of pulsed and coherent electromagnetic radiation and relies on the Hansch frequency comb technique well-known in ultrahigh-precision spectroscopy. A good matter candidate for testing the hypothesis is a polarized ultracold neutron gas for which the number of swapped neutrons is measured.Comment: 14 pages, 4 figures. Published version. Published in Phys. Rev.

Generalized hidden symmetries and the Kerr-Sen black hole

We elaborate on basic properties of generalized Killing-Yano tensors which naturally extend Killing-Yano symmetry in the presence of skew-symmetric torsion. In particular, we discuss their relationship to Killing tensors and the separability of various field equations. We further demonstrate that the Kerr-Sen black hole spacetime of heterotic string theory, as well as its generalization to all dimensions, possesses a generalized closed conformal Killing-Yano 2-form with respect to a torsion identified with the 3-form occuring naturally in the theory. Such a 2-form is responsible for complete integrability of geodesic motion as well as for separability of the scalar and Dirac equations in these spacetimes.Comment: 33 pages, no figure

FE analysis on tube hydroforming of small diametr ZM21 magnesium alloy tube

Tube hydroforming (THF) is one of the plasticity processing methods. Tubular parts, for instance automotive components are expanded by forces such as internal pressure and axial compression in order to deform an objective shape. THF has less restriction on shape and size of workpieces owing to adopting the liquid tool. The demand of a small diameter magnesium alloy tubular parts have been increased for applying small medical and electronic devices. In this study, it was investigated that influence of process conditions such as processing temperature, internal pressure and axial feeding amount on formability of small diameter ZM21 magnesium alloy tube with outer diameter of 2.0mm and thickness of 0.20mm. Furthermore, the processing conditions for improving the formability of material in THF were examined. For prior evaluation of deformation characteristics in the warm THF of small diameter ZM21 magnesium alloy tube, a finite element (FE) simulation was conducted. The FE method (FEM) code was used LS-DYNA 3D for analysis of the FE model of the tube and the dies. The material characteristics were obtained by tensile test and fracture test. From FE analysis results, it was elucidated that effect of the processing temperature, the variable internal pressure and the axial feeding amount on deformation behavior. The formability of ZM21 magnesium alloy tube was improved by processing at 250 C. The difference of deformation characteristic between FE results and experimental results was compared. As the results, the processing condition which could improve the formability of ZM21 tube was clarified using this FE model. The effect of adding the straightening stage in the loading path after the preform on formability was investigated. The thinning of the wall thickness of the tube was inhibited by calibration after the axial feeding

Rapid pre-gel visualization of proteins with mass spectrometry compatibility

Despite all of the prophecies of doom, gel electrophoresis is still prevalent in modern proteomic workflows. However, the currently used protein staining methods represent a serious bottleneck for a quick subsequent protein analysis using mass spectrometry. Substituting traditional protein stains by pre-gel derivatization with visible and mass spectrometry compatible reagents eliminates several processing steps and drastically reduces the sample preparation time. A defined chemistry permits seamless integration of such covalent protein staining methods into standardized bioinformatic pipelines. Using Uniblue A we could covalently stain simple to complex protein samples within 1 minute. Protein profiles on the gels were not compromised and MS/MS based sequence coverages higher than 80% could be obtained. In addition, the visual tracking of covalently stained proteins and peptides facilitates method development and validation. Altogether, this new chemo-proteomic approach enables true "at-line" analysis of proteins

Specific heat study of spin-structural change in pyrochlore Nd2_2Mo2_2O7_7

By measurements of specific heat, we have investigated the magnetic field ($H$) induced spin-structural change in Nd$_2$Mo$_2$O$_7$ that shows spin-chirality-related magneto-transport phenomena. A broad peak around 2 K caused by the ordering of 2-in 2-out structure of the Nd moments at zero $H$ shifts to the lower temperature ($T$) up to around 3 T and then to the higher $T$ above around 3 T with increasing $H$ for all the direction of $H$. This is due to the crossover from antiferromagnetic to ferromagnetic arrangement between the Nd and Mo moments. While the peak $T$ increases monotonically above 3 T for $H$//[100], another peak emerges around 0.9 K at 12 T for $H$//[111], which is ascribed to the ordering of 3-in 1-out structure. For $H$//[110], a spike like peak is observed at around 3 T, which is caused perhaps by some spin flip transition.Comment: 5 pages, 4 figure