Physical state representations and gauge fixing in string theory

We re-examine physical state representations in the covariant quantization of bosonic string. We especially consider one parameter family of gauge fixing conditions for the residual gauge symmetry due to null states (or BRST exact states), and obtain explicit representations of observable Hilbert space which include those of the DDF states. This analysis is aimed at giving a necessary ingredient for the complete gauge fixing procedures of covariant string field theory such as temporal or light-cone gauge.Comment: 16 page

Vibration problem of a spherical tank containing jet propellant: numerical simulations

This document is the final report on the joint research project on vibration problem of a spherical tank containing jet propellant between IHI, Japan and SES, University of Southampton, UK. The background of the project is described. The fundamental principles and numerical method used in numerical simulations are presented. The detailed FEA models for each studied cases are given. The calculation results are presented using tables, curves, figures as well as the attached data files. The available experiment results are listed to compare with the numerical calculations. The calculation results show a fundamental agreement with the experiment results. The numerical analysis confirms that:1)Due to water – tank interaction, the natural frequencies of the water – tank system are decreased with the water level increase. For the 25% water level, the natural frequencies, especially heave mode frequency, shows a significant decrease compared with the empty case. However, with continuing increase the filed water more than 25% level, the decrease gradient of the natural frequencies gradually tends to zero. In the 100% water case, the natural frequency of heave mode is about 200 Hz which can not equal zero.2)Considering free surface wave effect produces a lot of sloshing modes of very low frequencies compared with the natural frequencies of the dry tank structure. Therefore, for dynamic response analysis with high frequency excitations, the free surface wave may be neglected. However, to assess loads caused by sloshing modes, the free surface waves have to be considered.3)There exist relative big deformations at the four tank support places in several vibration modes, which may produce a large local stress at support places to cause the product fail in vibration environment. A strengthen local design at the support places is needed.4)The dynamic response results are affected by damping coefficients of all modes used in the dynamic response analysis. The damping coefficients are approximately presented and therefore, the numerical results are good reference for practical designs.The report confirms that the original purpose of this joint research project has well completed by IHI and SES

Klotho mice: a novel wound model of aged skin.

BackgroundAs the elderly population continues to expand, it becomes increasingly important to develop treatments to improve wound healing in the elderly. One problem limiting the research is the lack of appropriate animal models for wound healing in elderly patients. We hypothesized that the Klotho mouse of premature aging is a suitable animal model to shed light on many of the biological processes involved in aging skin.MethodsKlotho mice (kl/kl), Klotho-heterozygous mice (kl/+), and wild-type mice (+/+) were wounded, and the area of the wound was measured every 3 days until the wound was healed. To compare the klotho phenotype with wild-type mice, wounds were also harvested at 4 and 7 days after wounding. For histological examination, paraffin-embedded sections were stained with hematoxylin and eosin and Masson trichrome. Collagen expression in the wound was also studied by analyzing messenger RNA using real-time polymerase chain reaction.ResultsKlotho mice showed a significantly slower rate of wound closure compared with Klotho-heterozygous mice and wild-type mice. Histology showed substantial less healing and collagen deposition in the wounds of the Klotho mice. The expression of collagen messenger RNA in Klotho mice was also less than that in heterozygous and wild-type mice. The Klotho mice exhibited significant phenotypic similarities with aged skin, such as atrophy and delayed wound healing.ConclusionThese preliminary data suggest that the Klotho mouse may be a model to further investigate wound healing in the elderly

Maximal entanglement of two spinor Bose-Einstein condensates

Starting with two weakly-coupled anti-ferromagnetic spinor condensates, we show that by changing the sign of the coefficient of the spin interaction, $U_{2}$, via an optically-induced Feshbach resonance one can create an entangled state consisting of two anti-correlated ferromagnetic condensates. This state is maximally entangled and a generalization of the Bell state from two anti-correlated spin-1/2 particles to two anti-correlated spin$-N/2$ atomic samples, where $N$ is the total number of atoms.Comment: 5 pages, 3 figures, accepted for publication in PR

Vortex lattice for a holographic superconductor

We investigate the vortex lattice solution in a (2+1)-dimensional holographic model of superconductors constructed from a charged scalar condensate. The solution is obtained perturbatively near the second-order phase transition and is a holographic realization of the Abrikosov lattice. Below a critical value of magnetic field, the solution has a lower free energy than the normal state. Both the free energy density and the superconducting current are expressed by nonlocal functions, but they reduce to the expressions in the Ginzburg-Landau (GL) theory at long wavelength. As a result, a triangular lattice becomes the most favorable solution thermodynamically as in the GL theory of type II superconductors.Comment: v2: minor changes, references added; 11 pages, 2 figures: version to appear in PR