The space of linear anti-symplectic involutions is a homogenous space

In this note we prove that the space of linear anti-symplectic involutions is the homogenous space ${{{\rm Gl}(n, \mathbb{R})\backslash{\rm Sp}(n)}}$ . This result is motivated by the study of symmetric periodic orbits in the restricted 3-body problem.     

On a theorem by Ekeland-Hofer

In [EH89, Theorem 1] Ekeland-Hofer prove that for a centrally symmetric, restricted contact type hypersurface in ℝ²ⁿ and for any global, centrally symmetric Hamiltonian perturbation there exists a leaf-wise intersection point. In this note we show that if we replace restricted contact type by star-shaped, there exist infinitely many leaf-wise intersection points or a leaf-wise intersection point on a closed characteristic.     

Infinitely many leaf-wise intersections on cotangent bundles

If the homology of the free loop space of a closed manifold B$B$ is infinite dimensional then generically there exist infinitely many leaf-wise intersection points for fiberwise star-shaped hypersurfaces in T^∗B$T^{\ast }B$. We illustrate this in the case of the restricted three body problem.     

Superconducting gap structure of the 115s revisited

Density functional theory calculations of the electronic structure of Ce- and Pu-based heavy fermion superconductors in the so-called 115 family are performed. The gap equation is used to consider which superconducting order parameters are most favorable assuming a pairing interaction that is peaked at (π, π, qz)—the wavevector for the antiferromagnetic ordering found in close proximity. In addition to the commonly accepted dx2?y2 order parameter, there is evidence that an extended s-wave order parameter with nodes is also plausible. We discuss whether these results are consistent with current observations and possible measurements that could help distinguish between these scenarios.     

Growth and basic dielectric data of high quality TSCC crystals

Tris-sarcosine calcium chloride (TSCC) single crystals were grown from water solutions by the isothermal evaporation method. The growth solutions contained sarcosine and CaCl₂ either in stoichiometric or nonstoichiometric ratio. The required phase diagram sarcosine–CaCl₂ H₂O at 40 °C was determined by the synthetic method. PFT 400 MHz NMR was used for the analysis of organic impurities in sarcosine and TSCC. The crystals grown from both types of solutions had maximum values of the dielectric permittivity 10 to 200 times larger than those measured by other authors at comparable measuring frequencies and fields. It is discussed in terms of crystal quality.     

Leitfähigkeits- und Halleffektmessungen an Tellur-Epitaxieschichten auf KCl

The temperature dependence of resistivity of epitactixial thin tellurium films grown on (110) KCl is contrary to the results well known from single crystals. For interpretation of this discrepancy a model is proposed which makes use of piezoresistance effects. This model is in qualitative and quantitative agreement with measurements.