We prove the following estimate for the spectrum of the normalized Laplace operator ∆ on a finite graph G, 1− (1− k[t]) t ≤ λ1 ≤ · · · ≤ λN−1 ≤ 1 + (1− k[t]) 1 t , ∀ integers t ≥ 1. Here k[t] is a lower bound for the Ollivier-Ricci curvature on the neighborhood graph G[t] (here we use the convention G[1] = G), which was introduced by Bauer-Jost. In particular, when t = 1 this is Ollivier’s esti...

We present a calculation of the ground state energy of massive spinor fields and massive scalar fields in the background of an inhomogeneous magnetic string with potential given by a delta function. The zeta functional regularization is used and the lowest heat kernel coefficients are calculated. The rest of the analytical calculation adopts the Jost function formalism. In the numerical part of...

We establish a previously conjectured connection between p-adics and quantum groups. We find in Sklyanin’s two parameter elliptic quantum algebra and its generalizations, the conceptual basis for the Macdonald polynomials, which “interpolate” between the zonal spherical functions of related real and p-adic symmetric spaces. The elliptic quantum algebras underlie the Zn-Baxter models. We show th...

In these notes we compute the geodesic curvature on a surface in isothermal coordinates and use it to prove the local Gauß-Bonnet Theorem. These remarks are a continuation of my notes [T] whose notation we continue to employ. 1. Isothermal Coordinates of a Surface. The computations are facilitated by using a special coordinate system in which the metric and the resulting formulas take a particu...

A reference potential approach to the one-dimensional quantummechanical inverse problem is developed. All spectral characteristics of the system, including its discrete energy spectrum, the full energy dependence of the phase shift, and the Jost function, are expected to be known. The technically most complicated task in ascertaining the potential, solution of a relevant integral equation, has ...