535 research outputs found
Four-dimensional BPS-spectra via M-theory
We consider the realization of four-dimensional theories with N = 2
supersymmetry as M-theory configurations including a five-brane. Our emphasis
is on the spectrum of massive states, that are realized as two-branes ending on
the five-brane. We start with a determination of the supersymmetries that are
left unbroken by the background metric and five-brane. We then show how the
central charge of the N = 2 algebra arises from the central charge associated
with the M-theory two-brane. This determines the condition for a two-brane
configuration to be BPS-saturated in the four-dimensional sense. By imposing
certain conditions on the moduli, we can give concrete examples of such
two-branes. This leads us to conjecture that vectormultiplet and hypermultiplet
BPS-saturated states correspond to two-branes with the topology of a cylinder
and a disc respectively. We also discuss the phenomenon of marginal stability
of BPS-saturated states.Comment: 18 pages, 3 figures, uses harvmac. References adde
BPS partition functions in N = 4 Yang-Mills theory on T^4
We consider N = 4 Yang-Mills theory on a flat four-torus with the R-symmetry
current coupled to a flat background connection. The partition function depends
on the coupling constant of the theory, but when it is expanded in a power
series in the R-symmetry connection around the loci at which one of the
supersymmetries is unbroken, the constant and linear terms are in fact
independent of the coupling constant and can be computed at weak coupling for
all non-trivial 't Hooft fluxes. The case of a trivial 't Hooft flux is
difficult because of infrared problems, but the corresponding terms in the
partition function are uniquely determined by S-duality.Comment: 23 pages, v2 Minor correction
A class of six-dimensional conformal field theories
We describe a class of six-dimensional conformal field theories that have
some properties in common with and possibly are related to a subsector of the
tensionless string theories. The latter theories can for example give rise to
four-dimensional superconformal Yang-Mills theories upon
compactification on a two-torus. Just like the tensionless string theories, our
theories have an -classification, but no other discrete or continuous
parameters. The Hilbert space carries an irreducible representation of the same
Heisenberg group that appears in the tensionless string theories, and the
`Wilson surface' observables obey the same superselection rules. When
compactified on a two-torus, they have the same behaviour under -duality as
super Yang-Mills theory. Our theories are natural generalizations of the
two-form with self-dual field strength that is part of the world-volume theory
of a single five-brane in -theory, and the theory can in fact be
seen as arising from non-interacting chiral two-forms by factoring out the
collective `center of mass' degrees of freedom.Comment: 8 pages. More pedagogical presentation, added section on relationship
to d = 4 Yang-Mills theor
Duality and the Legendre Transform
We define a weak-strong coupling transformation based on the Legendre
transformation of the effective action. In the case of N\es 2 supersymmetric
Yang-Mills theory, this coincides with the duality transform on the low energy
effective action considered by Seiberg and Witten. This Legendre transform
interpretation of duality generalizes directly to the full effective action,
and in principle to other theories.Comment: 6 pages, LaTe
Conformal Anomaly Of Submanifold Observables In AdS/CFT Correspondence
We analyze the conformal invariance of submanifold observables associated
with -branes in the AdS/CFT correspondence. For odd , the resulting
observables are conformally invariant, and for even , they transform with a
conformal anomaly that is given by a local expression which we analyze in
detail for Comment: 11 p
The volume of causal diamonds, asymptotically de Sitter space-times and irreversibility
In this note we prove that the volume of a causal diamond associated with an
inertial observer in asymptotically de Sitter 4-dimensional space-time is
monotonically increasing function of cosmological time. The asymptotic value of
the volume is that of in maximally symmetric de Sitter space-time. The
monotonic property of the volume is checked in two cases: in vacuum and in the
presence of a massless scalar field. In vacuum, the volume flow (with respect
to cosmological time) asymptotically vanishes if and only if future space-like
infinity is 3-manifold of constant curvature. The volume flow thus represents
irreversibility of asymptotic evolution in spacetimes with positive
cosmological constant.Comment: 15 pages, no figures; v.2: conjecture 1 on p. 11 made more precise;
version published in jhe
Diffeomorphisms and Holographic Anomalies
Using the relation between diffeomorphisms in the bulk and Weyl
transformations on the boundary we study the Weyl transformation properties of
the bulk metric on shell and of the boundary action. We obtain a universal
formula for one of the classes of trace anomalies in any even dimension in
terms of the parameters of the gravity action.Comment: 12 pages, harvma
Energy and Momentum Distributions of a (2+1)-dimensional black hole background
Using Einstein, Landau-Lifshitz, Papapetrou and Weinberg energy-momentum
complexes we explicitly evaluate the energy and momentum distributions
associated with a non-static and circularly symmetric three-dimensional
spacetime. The gravitational background under study is an exact solution of the
Einstein's equations in the presence of a cosmological constant and a null
fluid. It can be regarded as the three-dimensional analogue of the Vaidya
metric and represents a non-static spinless (2+1)-dimensional black hole with
an outflux of null radiation. All four above-mentioned prescriptions give
exactly the same energy and momentum distributions for the specific black hole
background. Therefore, the results obtained here provide evidence in support of
the claim that for a given gravitational background, different energy-momentum
complexes can give identical results in three dimensions. Furthermore, in the
limit of zero cosmological constant the results presented here reproduce the
results obtained by Virbhadra who utilized the Landau-Lifshitz energy-momentum
complex for the same (2+1)-dimensional black hole background in the absence of
a cosmological constant.Comment: 19 pages, LaTeX, v3: references added, to appear in Int.J.Mod.Phys.
A note on a gauge-gravity relation and functional determinants
We present a refinement of a recently found gauge-gravity relation between
one-loop effective actions: on the gauge side, for a massive charged scalar in
2d dimensions in a constant maximally symmetric electromagnetic field; on the
gravity side, for a massive spinor in d-dimensional (Euclidean) anti-de Sitter
space. The inclusion of the dimensionally regularized volume of AdS leads to
complete mapping within dimensional regularization. In even-dimensional AdS, we
get a small correction to the original proposal; whereas in odd-dimensional
AdS, the mapping is totally new and subtle, with the `holographic trace
anomaly' playing a crucial role.Comment: 6 pages, io
Conformal Field Theory Correlators from Classical Field Theory on Anti-de Sitter Space II. Vector and Spinor Fields
We use the AdS/CFT correspondence to calculate CFT correlation functions of
vector and spinor fields. The connection between the AdS and boundary fields is
properly treated via a Dirichlet boundary value problem.Comment: 14 pages, LaTeX2e with amsmath,amsfonts packages; v2:interactions
section corrected, reference adde
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