Topological defects in 1D elastic waves

It has been recently shown theoretically that a topological defect in a 1D periodic potential may give rise to two localized states within the energy gaps. In this work we present an experimental realization of this effect for the case of torsional waves in elastic rods. We also show numerically that three, or even more, localized states can be present if the parameters characterizing the topological defect are suitably varied.Comment: 3 pages, 4 figures, accepted in Physica

Analytic Non-integrability in String Theory

Using analytic techniques developed for Hamiltonian dynamical systems we show that a certain classical string configurations in AdS_5 x X_5 with X_5 in a large class of Einstein spaces, is non-integrable. This answers the question of integrability of string on such backgrounds in the negative. We consider a string localized in the center of AdS_5 that winds around two circles in the manifold X_5.Comment: 14 page

Partition Functions of Pure Spinors

We compute partition functions describing multiplicities and charges of massless and first massive string states of pure-spinor superstrings in 3,4,6,10 dimensions. At the massless level we find a spin-one gauge multiplet of minimal supersymmetry in d dimensions. At the first massive string level we find a massive spin-two multiplet. The result is confirmed by a direct analysis of the BRST cohomology at ghost number one. The central charges of the pure spinor systems are derived in a manifestly SO(d) covariant way confirming that the resulting string theories are critical. A critical string model with N=(2,0) supersymmetry in d=2 is also described.Comment: LaTex, 30 p