The temperature and magnetic field dependence of the in-plane thermal conductivity kappa of the iron-arsenide superconductor Ba(Fe(1-x)Co(x))2As2 was measured down to T approximately 50 mK and up to H = 15 T as a function of Co concentration x in the range 0.048 < or = x < or = 0.114. At H = 0, a negligible residual linear term in kappa/T as T-->0 at all x shows that the superconducting gap has...

If fR n g 1 n=1 is a sequence of hyperbolic Riemann surfaces such that for any r > 0 a hyperbolic ball of radius r embeds isometrically into R n for all n suuciently large, then as n ! 1 the inner radii of the associated Teichm uller spaces i(T(R n)) ! 2. A straightforward consequence of this is that if a Riemann surface R contains arbitrarily large hyperbolic balls then i(T(R)) = 2. Let ? be a...

A graph drawn on the plane is 2-immersed in if each edge crossed by at most two other edges (this drawing of called a 2-immersion plane). 2-planar it can be plane. We consider class T all finite planar graphs triangulating such that have no loops and multiple edges, vertices degree 5 6 only, distance between any 5-valent least 4. describe possible 2-immersions for 2-immersions, we ways which ne...

Geometrical and topological properties of the quasi-plane Szekeres model and of the plane symmetric dust model are discussed. Some related comments on the quasihyperbolical model are made. These properties include: (1) The pattern of expansion in the plane symmetric case, and the Newtonian model that imitates it; (2) The possibility of toroidal topology of the t = const sections in the plane sy...

We present results obtained (by exact diagonalization) for the problem of two t−J planes with an interlayer coupling t⊥. Our results for small hole concentrations show that in-plane superconducting correlations are enhanced by t⊥. When the constraint on double occupancy in the t−Jmodel is relaxed, the enhancement disappears. These results illustrate the inter–layer tunneling mechanism for super...

Hall angle in high-T c cuprates: Anomalous temperature dependence and anisotropic scattering Abstract. The anisotropy of the scattering rates, 1/τ tr ∝ T and 1/τ H ∝ T 2 , implied effectively by the anomalous temperature dependence of the normal-state in-plane Hall angle, cot θ ∝ T 2 , observed in the high-T c lay-ered cuprates is reasoned out to be a natural consequence of the semiclassical Bo...