Strong 3p -T1u Hybridization in Ar@C60

Multilayers of fullerenes with and without endohedral Ar units, C60 and Ar@C60, were investigated by photoemission and density functional theory. The stoichiometry and the endohedral nature of Ar is checked by x-ray photoelectron spectroscopy and x-ray photoelectron diffraction. Valence band ultraviolet photoemission spectra show a strong hybridisation of the Ar 3p valence shell with the 6T1u molecular orbital of C60. A hybridisation gap of 1.6 +/- 0.2 eV is found. This is in agreement with density functional theory (DFT) that predicts 1.47 eV, and indicates Ar@C60 to be a noble gas compound with a strong coupling between Ar and the C60 cage. No giant Ar photoemission cross section as predicted for the gas phase in [Phys. Rev. Lett. 99, 243003 (2007)] was found

Pressure-induced enhancement of superconductivity and superconducting-superconducting transition in CaC_6\_6

We measured the electrical resistivity, $\varrho(T)$, of superconducting CaC$\_6$ at ambient and high pressure up to 16 GPa. For $P \leq$8 GPa, we found a large increase of $T\_c$ with pressure from 11.5 up to 15.1 K. At 8 GPa, $T\_c$ drops and levels off at 5 K above 10 GPa. Correspondingly, the residual $\varrho$ increases by $\approx$ 200 times and the $\varrho(T)$ behavior becomes flat. The recovery of the pristine behavior after depressurization is suggestive of a phase transition at 8 GPa between two superconducting phases with good and bad metallic properties, the latter with a lower $T\_c$ and more static disorder

Motion plan changes predictably in dyadic reaching

Parents can effortlessly assist their child to walk, but the mechanism behind such physical coordination is still unknown. Studies have suggested that physical coordination is achieved by interacting humans who update their movement or motion plan in response to the partner's behaviour. Here, we tested rigidly coupled pairs in a joint reaching task to observe such changes in the partners' motion plans. However, the joint reaching movements were surprisingly consistent across different trials. A computational model that we developed demonstrated that the two partners had a distinct motion plan, which did not change with time. These results suggest that rigidly coupled pairs accomplish joint reaching movements by relying on a pre-programmed motion plan that is independent of the partner's behaviour

Bilinear Equations and B\"acklund Transformation for Generalized Ultradiscrete Soliton Solution

Ultradiscrete soliton equations and B\"acklund transformation for a generalized soliton solution are presented. The equations include the ultradiscrete KdV equation or the ultradiscrete Toda equation in a special case. We also express the solution by the ultradiscrete permanent, which is defined by ultradiscretizing the signature-free determinant, that is, the permanent. Moreover, we discuss a relation between B\"acklund transformations for discrete and ultradiscrete KdV equations.Comment: 11 page

Transition state method and Wannier functions

We propose a computational scheme for materials where standard Local Density Approximation (LDA) fails to produce a satisfactory description of excitation energies. The method uses Slater's "transition state" approximation and Wannier functions basis set. We define a correction to LDA functional in such a way that its variation produces one-electron energies for Wannier functions equal to the energies obtained in "transition state" constrained LDA calculations. In the result eigenvalues of the proposed functional could be interpreted as excitation energies of the system under consideration. The method was applied to MgO, Si, NiO and BaBiO$_3$ and gave an improved agreement with experimental data of energy gap values comparing with LDA.Comment: 13 pages, 6 figures, 1 tabl