1,264 research outputs found
Global anomalies in M-theory
We first consider M-theory formulated on an open eleven-dimensional
spin-manifold. There is then a potential anomaly under gauge transformations on
the E_8 bundle that is defined over the boundary and also under diffeomorphisms
of the boundary. We then consider M-theory configurations that include a
five-brane. In this case, diffeomorphisms of the eleven-manifold induce
diffeomorphisms of the five-brane world-volume and gauge transformations on its
normal bundle. These transformations are also potentially anomalous. In both of
these cases, it has previously been shown that the perturbative anomalies, i.e.
the anomalies under transformations that can be continuously connected to the
identity, cancel. We extend this analysis to global anomalies, i.e. anomalies
under transformations in other components of the group of gauge transformations
and diffeomorphisms. These anomalies are given by certain topological
invariants, that we explicitly construct.Comment: 14 pages, harvma
On Flux Quantization In M-Theory And The Effective Action
The quantization law for the antisymmetric tensor field of -theory
contains a gravitational contribution not known previously. When it is
included, the low energy effective action of -theory, including one-loop and
Chern-Simons contributions, is well-defined. The relation of -theory to the
heterotic string greatly facilitates the analysis.Comment: 17 pp, harvmac; A correction and additional application have been
adde
Domain Wall Fermions and the Eta Invariant
We extend work by Callan and Harvey and show how the phase of the chiral
fermion determinant in four dimensions is reproduced by zeromodes bound to a
domain wall in five dimensions. The analysis could shed light on the
applicability of zeromode fermions and the vacuum overlap formulation of
Narayanan and Neuberger for chiral gauge theories on the lattice.Comment: uuencoded file with 3 figures; uses macros harvmac, epsf. Revised
discussion of the Chern-Simons form and SU(2) anomaly in section 4, as well
as additional minor change
Anomalies and inflow on D-branes and O-planes
We derive the general form of the anomaly for chiral spinors and self-dual
antisymmetric tensors living on D-brane and O-plane interesections, using both
path-integral and index theorem methods. We then show that the anomalous
couplings to RR forms of D-branes and O-planes in a general background are
precisely those required to cancel these anomalies through the inflow
mechanism. This allows, for instance, for local anomaly cancellation in generic
orientifold models, the relevant Green-Schwarz term being given by the sum of
the anomalous couplings of all the D-branes and O-planes in the model.Comment: 24 pages, LaTex file, no figure
An alternative approach to KP hierarchy in matrix models
We show that there exists an alternative procedure in order to extract
differential hierarchies, such as the KdV hierarchy, from one--matrix models,
without taking a continuum limit. To prove this we introduce the Toda lattice
and reformulate it in operator form. We then consider the reduction to the
systems appropriate for one--matrix model.Comment: 18
Anomaly cancellation in M-theory: a critical review
We carefully review the basic examples of anomaly cancellation in M-theory:
the 5-brane anomalies and the anomalies on S^1/Z_2. This involves cancellation
between quantum anomalies and classical inflow from topological terms. To
correctly fix all coefficients and signs, proper attention is paid to issues of
orientation, chirality and the Euclidean continuation. Independent of the
conventions chosen, the Chern-Simons and Green-Schwarz terms must always have
the same sign. The reanalysis of the reduction to the heterotic string on
S^1/Z_2 yields a surprise: a previously neglected factor forces us to slightly
modify the Chern-Simons term, similar to what is needed for cancelling the
normal bundle anomaly of the 5-brane. This modification leads to a local
cancellation of the anomaly, while maintaining the periodicity on S^1.Comment: 35 page
Dilaton Contact Terms in the Bosonic and Heterotic Strings
Dilaton contact terms in the bosonic and heterotic strings are examined
following the recent work of Distler and Nelson on the bosonic and semirigid
strings. In the bosonic case dilaton two-point functions on the sphere are
calculated as a stepping stone to constructing a `good' coordinate family for
dilaton calculations on higher genus surfaces. It is found that dilaton-dilaton
contact terms are improperly normalized, suggesting that the interpretation of
the dilaton as the first variation of string coupling breaks down when other
dilatons are present. It seems likely that this can be attributed to the
tachyon divergence found in \TCCT. For the heterotic case, it is found that
there is no tachyon divergence and that the dilaton contact terms are properly
normalized. Thus, a dilaton equation analogous to the one in topological
gravity is derived and the interpretation of the dilaton as the string coupling
constant goes through.Comment: 44 pages, Figures now included. This replacement version includes the
7 figures as PostScript files appended to the end and the macros to insert
them into the text. Also some typos in intermediate formulae were correcte
Iterative Solution of the Supereigenvalue Model
An integral form of the discrete superloop equations for the supereigenvalue
model of Alvarez-Gaume, Itoyama, Manes and Zadra is given. By a change of
variables from coupling constants to moments we find a compact form of the
planar solution for general potentials. In this framework an iterative scheme
for the calculation of higher genera contributions to the free energy and the
multi-loop correlators is developed. We present explicit results for genus one.Comment: 21 pages, LaTeX, no figure
On the "Universal" N=2 Supersymmetry of Classical Mechanics
In this paper we continue the study of the geometrical features of a
functional approach to classical mechanics proposed some time ago. In
particular we try to shed some light on a N=2 "universal" supersymmetry which
seems to have an interesting interplay with the concept of ergodicity of the
system. To study the geometry better we make this susy local and clarify
pedagogically several issues present in the literature. Secondly, in order to
prepare the ground for a better understanding of its relation to ergodicity, we
study the system on constant energy surfaces. We find that the procedure of
constraining the system on these surfaces injects in it some local grassmannian
invariances and reduces the N=2 global susy to an N=1.Comment: few misprints fixed with respect to Int.Jour.Mod.Phys.A vol 16, no15
(2001) 270
Desperately Seeking Chiral Fermions
Chiral fermions can (presumably) be constructed by introducing two
regulators, one for the gauge fields (e.g. a lattice), and another for the
fermion functional integrals in a fixed (regulated) gauge field. This talk
discusses cutoff effects arising from the regulator of the fermions.Comment: 4 pages, contribution to Lattice '95 Postscript at
http://www-theory.fnal.gov/people/ask/TeX/lat95/chiral.p
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