21 research outputs found
From Ramond Fermions to Lame Equations for Orthogonal Curvilinear Coordinates
We show how Ramond free neutral Fermi fields lead to a -function theory
of BKP type which describes iso-orthogonal deformations of systems of ortogonal
curvilinear coordinates. We also provide a vertex operator representation for
the classical Ribaucour transformation.Comment: 14 pages, LaTeX2e with AMSLaTeX and Babel package
Hawking Temperature and String Scattering off the 2+1 Black Hole
The 2+1 black hole anti de Sitter solution, obtained as a special limit of
the conformally exact coset WZW model to all
orders in 1/k, is investigated with respect to tachyon scattering. We calculate
the off-shell reflection and transmission coefficients and we find an
expression for the Hawking temperature, which in a certain limit reduces to the
statistical result.Comment: 12 pages Latex + 2 figures (not included), NBI-HE-94-1
The instanton contributions to Yang-Mills theory on the torus: localization, Wilson loops and the perturbative expansion
The instanton contributions to the partition function and to homologically
trivial Wilson loops for a U(N) Yang-Mills theory on a torus are
analyzed. An exact expression for the partition function is obtained as a sum
of contributions localized around the classical solutions of Yang-Mills
equations, that appear according to the general classification of Atiyah and
Bott. Explicit expressions for the exact Wilson loop averages are obtained when
N=2, N=3. For general the contribution of the zero-instanton sector has
been carefully derived in the decompactification limit, reproducing the sum of
the perturbative series on the plane, in which the light-cone gauge Yang-Mills
propagator is prescribed according to Wu-Mandelstam-Leibbrandt (WML). Agreement
with the results coming from is therefore obtained, confirming the truly
perturbative nature of the WML computations.Comment: 28 pages, revtex, no figure
Topology at the Planck Length
A basic arbitrariness in the determination of the topology of a manifold at
the Planck length is discussed. An explicit example is given of a `smooth'
change in topology from the 2-sphere to the 2-torus through a sequence of
noncommuting geometries. Applications are considered to the theory of D-branes
within the context of the proposed (atrix) theory.Comment: Orsay Preprint 97/34, 17 pages, Late