We study the back-reaction of large-N D0-brane charge on the maximally supersymmetric pp-wave background. This gives the type IIA geometry on which string theory is dual to the BMN Matrix model. We identify the energy scales where perturbation theory in this Matrix model is valid. We derive the supermembrane action on a general pp-wave background and through this, derive the Matrix model. At th...

We show, by explicit computation, that bare lattice perturbation theory in the two-dimensional O(n) nonlinear σ models with superinstanton boundary conditions is divergent in the limit of an infinite number of points |Λ|. This is the analogue of David’s statement that renormalized perturbation theory of these models is infrared divergent in the limit where the physical size of the box tends to ...

In general quantum systems there are two kinds of spacetime modes, those that fluctuate and those that do not. Fluctuating modes have normalizable wavefunctions. In the context of 2D gravity and “non-critical” string theory these are called macroscopic states. The theory is independent of the initial Euclidean background values of these modes. Nonfluctuating modes have non-normalizable wavefunc...

Recent work on gravitational geons is extended to examine the stability properties of gravitational and electromagnetic geon constructs. All types of geons must possess the property of regularity, self-consistency and quasistability on a time-scale much longer than the period of the comprising waves. Standard perturbation theory, modified to accommodate timeaveraged fields, is used to test the ...

With the aim of extending the gauge theory – matrix model connection to more general matter representations, we prove that for various two-index tensors of the classical gauge groups, the perturbative contributions to the glueball superpotential reduce to matrix integrals. Contributing diagrams consist of certain combinations of spheres, disks, and projective planes, which we evaluate to four a...

In the framework of a 2HDM effective lagrangian for the MSSM, we analyse some phenomenological implications of the soft SUSY breaking effects that modify the relation between the bottom mass and the bottom Yukawa coupling. We derive a resummation of the dominant supersymmetric corrections for large values of tanβ to all orders in perturbation theory. With the help of the operator product expans...

Computing the ne canonical-structure elements of matrices and matrix pencils are ill-posed problems. Therefore, besides knowing the canonical structure of a matrix or a matrix pencil, it is equally important to know what are the nearby canonical structures that explain the behavior under small perturbations. Qualitative strata information is provided by our StratiGraphtool. Here, we present low...

The magnitude of m u , m d and m s is discussed on the basis of Chiral Perturbation Theory. In particular, the claim that m u = 0 leads to a coherent picture for the low energy structure of QCD is examined in detail. It is pointed out that this picture leads to violent flavour asymmetries in the matrix elements of the scalar and pseudoscalar operators, which are in conflict with the hypothesis ...

We discuss the application of perturbation theory to a system of particles confined in a spherical box. A simple argument shows that the particles behave almost independently in sufficiently strong confinement. We choose the helium atom with a moving nucleus as a particular example and compare results of first order with those for the nucleus clamped at the center of the box. We provide a suita...

We give a sharp estimate for the eigenvectors of a positive deenite Hermitian matrix under a oating-point perturbation. The proof is elementary. Recently there have been a number of papers on eigenvector perturbation bounds that involve a perturbation of the matrix which is small in some relative sense, including the typical rounding errors in matrix elements ((1], 2], 10], 8], 4], 5]). The pro...