Chern numbers for fermionic quadrupole systems

The authors analyse families of quantum quadrupole Hamiltonians H= Sigma alpha beta Qalpha beta Jalpha Jbeta for half-odd-integer spin, and calculate the second Chern numbers of the energy levels. Each non-zero integer occurs only a finite number of times. The adiabatic time evolution, the non-Abelian generalisation of Berry's phase, is different for each system, in contrast to Berry's example. The j=3/2 and j=1/2 cases previously analysed are the only ones with self-dual curvatures and SO(5) symmetry

An Ugaritic text related to the fertility cult (KTU 1. 23)

A contextual interpretation is applied to a tablet in alphabetic cuneiform from the 14th cent. B.C., found at Ras Shamra-Ugarit in Northern Syria, published in 1933. This ancient Canaanite text "Birth of Gracious Gods" contains a liturgical introduction and an epic poem: The god Il fathered sons from two wives. This fertility ritual was compared to other rites, such as hydrophoria - this connection is rather tenuous - and sacred marriage. It was also explained as a reflection of the progress of human society toward agriculture. Even after successful efforts in general interpretation, further studies of details are needed. The parallel expressions "seven years" - "eight cycles" indicate not an exact, but a considerable interval of time. Two gods "Dawn" and "Dusk" were sons of different mothers, but they were born from the same father at the same time; thus they may - as functional twins - be helpful in assuring abundant rains.peer-reviewe

Space Shuttle orbiter modifications to support Space Station Freedom

The Space Shuttle will be the primary vehicle to support the launch, assembly, and maintenance of the Space Station Freedom (SSF). In order to accommodate this function, the Space Shuttle orbiter will require significant modifications. These modifications are currently in development in the Space Shuttle Program. The requirements for the planned modifications to the Space Shuttle orbiter are dependent on the design of the SSF. Therefore, extensive coordination is required with the Space Station Freedom Program (SSFP) in order to identify requirements and resolve integration issues. This paper describes the modifications to the Space Shuttle orbiter required to support SSF assembly and operations

Topological Invariants in Fermi Systems with Time-Reversal Invariance

We discuss topological invariants for Fermi systems that have time-reversal invariance. The TKN^2 integers (first Chern numbers) are replaced by second Chern numbers, and Berry's phase becomes a unit quaternion, or equivalently an element of SU(2). The canonical example playing much the same role as spin ½ in a magnetic field is spin ½ in a quadrupole electric field. In particular, the associated bundles are nontrivial and have ± 1 second Chern number. The connection that governs the adiabatic evolution coincides with the symmetric SU(2) Yang-Mills instanton

AkademikerInnen mit Behinderungen und chronischen Erkrankungen. Erfahrungen beim Berufseinstieg, Unterstützungsstrukturen und Handlungsbedarf aus Sicht von Betroffenen und ExpertInnen. Teil 2 der Zusatzstudie im Rahmen der Studierenden-Sozialerhebung 2011.

aus dem Inhaltsverzeichnis: Einleitung; Rahmenbedingungen für den Berufseinstieg; Problemwahrnehmung und Unterstützungsangebote aus ExpertInnensicht; Berufseinstieg aus Sicht von AbsolventInnen; Zusammenfassung und Schlussfolgerungen; Literatur; Anhang

Darboux-Egoroff Metrics, Rational Landau-Ginzburg Potentials and the Painleve VI Equation

We present a class of three-dimensional integrable structures associated with the Darboux-Egoroff metric and classical Euler equations of free rotations of a rigid body. They are obtained as canonical structures of rational Landau-Ginzburg potentials and provide solutions to the Painleve VI equation.Comment: 20 page

Observation of a non-adiabatic geometric phase for elastic waves

We report the experimental observation of a geometric phase for elastic waves in a waveguide with helical shape. The setup reproduces the experiment by Tomita and Chiao [A. Tomita, R.Y. Chiao, Phys. Rev. Lett. 57 (1986) 937-940, 2471] that showed first evidence of a Berry phase, a geometric phase for adiabatic time evolution, in optics. Experimental evidence of a non-adiabatic geometric phase has been reported in quantum mechanics. We have performed an experiment to observe the polarization transport of classical elastic waves. In a waveguide, these waves are polarized and dispersive. Whereas the wavelength is of the same order of magnitude as the helix's radius, no frequency dependent correction is necessary to account for the theoretical prediction. This shows that in this regime, the geometric phase results directly from geometry and not from a correction to an adiabatic phase.Comment: 13 figure