Motivated by the recent HERA events which are consistent with a possible leptoquark interpretation, we discuss the prospects for including additional light colour triplets and anti-triplets in the spectrum of supersymmetric unified theories. We focus on a particular string-inspired Pati-Salam model, and propose a simple mechanism by which a light colour triplet of charge -1/3 plus anti-triplet ...

We derive the universal threshold corrections in heterotic string theory including a continuous Wilson line. Unification of gauge and gravitational couplings is shown to be possible even within perturbative string theory. The relative importance of gauge group dependent and independent thresholds on unification is clarified. Equipped with these results we can then attempt an extrapolation to th...

This Korea-USA collaborative project, sponsored by AOARD for 2 years (April 18, 2013 April 17, 2015), “A study of material and optical properties of nano diamond wires (AOARD134085)”, aspired to find a way to synthesize a new form of carbon, crystalline diamond nanowires, and then to characterize them for device applications in nanophotonics, nanoelectronics, and quantum information processing....

The paper presents a method to recover exponential accuracy at all points (including at the discontinuities themselves), from the knowledge of an approximation to the interpolation polynomial (or trigonometrical polynomial). We show that if we are given the collocation point values (or' an highly accurate approximation) at the Gauss or Gauss-Lobatto points, we can reconstruct an uniform exponen...

We are interested in variational problems of the form min ∫ W (∇u) dx, with W nonconvex. The theory of relaxation allows one to calculate the minimum value, but it does not determine a well-defined “solution” since minimizing sequences are far from unique. A natural idea for determining a solution is regularization, i.e. the addition of a higher order term such as ǫ|∇∇u|2. But what is the behav...

We are grateful to the referees and Benedikt Pötscher for their helpful and constructive comments+ The research of the first author was partially supported by OTKA grants T37668 and T43037 and NSF-OTKA grant INT0223262+ The research of the second author was partially supported by NATO grant PST+EAP+CLG 980599 and NSF-OTKA grant INT-0223262+ Address correspondence to István Berkes, Graz Universi...

We continue our investigation of overcoming Gibbs phenomenon, i.e., to obtain exponential accuracy at all points (including at the discontinuities themselves), from the knowledge of a spectral partial sum of a discontinuous but piecewise analytic function. We show that if we are given the rst N Gegenbauer expansion coe cients, based on the Gegenbauer polynomials C k (x) with the weight function...