938 research outputs found
On Five-dimensional Superspaces
Recent one-loop calculations of certain supergravity-mediated quantum
corrections in supersymmetric brane-world models employ either the component
formulation (hep-th/0305184) or the superfield formalism with only half of the
bulk supersymmetry manifestly realized (hep-th/0305169 and hep-th/0411216).
There are reasons to expect, however, that 5D supergraphs provide a more
efficient setup to deal with these and more involved (in particular,
higher-loop) calculations. As a first step toward elaborating such supergraph
techniques, we develop in this letter a manifestly supersymmetric formulation
for 5D globally supersymmetric theories with eight supercharges. Simple rules
are given to reduce 5D superspace actions to a hybrid form which keeps manifest
only the 4D, N=1 Poincare supersymmetry. (Previously, such hybrid actions were
carefully worked out by rewriting the component actions in terms of simple
superfields). To demonstrate the power of this formalism for model building
applications, two families of off-shell supersymmetric nonlinear sigma-models
in five dimensions are presented (including those with cotangent bundles of
Kahler manifolds as target spaces). We elaborate, trying to make our
presentation maximally clear and self-contained, on the techniques of 5D
harmonic and projective superspaces used at some stages in this letter.Comment: 46 pages, 3 figures. V5: version published in JHE
Matrix Compactification On Orientifolds
Generalizing previous results for orbifolds, in this paper we describe the
compactification of Matrix model on an orientifold which is a quotient space as
a Yang-Mills theory living on a quantum space. The information of the
compactification is encoded in the action of the discrete symmetry group G on
Euclidean space and a projective representation U of G. The choice of Hilbert
space on which the algebra of U is realized as an operator algebra corresponds
to the choice of a physical background for the compactification. All these data
are summarized in the spectral triple of the quantum space.Comment: 28 pages, late
Elliptic Genus of E-strings
We study a family of 2d N=(0,4) gauge theories which describes at low energy
the dynamics of E-strings, the M2-branes suspended between a pair of M5 and M9
branes. The gauge theory is engineered using a duality with type IIA theory,
leading to the D2-branes suspended between an NS5-brane and 8 D8-branes on an
O8-plane. We compute the elliptic genus of this family of theories, and find
agreement with the known results for single and two E-strings. The partition
function can in principle be computed for arbitrary number of E-strings, and we
compute them explicitly for low numbers. We test our predictions against the
partially known results from topological strings, as well as from the instanton
calculus of 5d Sp(1) gauge theory. Given the relation to topological strings,
our computation provides the all genus partition function of the refined
topological strings on the canonical bundle over 1/2 K3.Comment: 49 pages, 2 figure
Monopole Bundles over Fuzzy Complex Projective Spaces
We give a construction of the monopole bundles over fuzzy complex projective
spaces as projective modules. The corresponding Chern classes are calculated.
They reduce to the monopole charges in the N -> infinity limit, where N labels
the representation of the fuzzy algebra.Comment: 30 pages, LaTeX, published version; extended discussion on asymptotic
Chern number
Unoriented D-brane Instantons vs Heterotic worldsheet Instantons
We discuss Fermi interactions of four hyperini generated by ``stringy''
instantons in a Type I / Heterotic dual pair on T^4/Z_2.Comment: Minor corrections and clarifications. Added reference
Special Geometry of Euclidean Supersymmetry III: the local r-map, instantons and black holes
We define and study projective special para-Kahler manifolds and show that
they appear as target manifolds when reducing five-dimensional vector
multiplets coupled to supergravity with respect to time. The dimensional
reductions with respect to time and space are carried out in a uniform way
using an epsilon-complex notation. We explain the relation of our formalism to
other formalisms of special geometry used in the literature. In the second part
of the paper we investigate instanton solutions and their dimensional lifting
to black holes. We show that the instanton action, which can be defined after
dualising axions into tensor fields, agrees with the ADM mass of the
corresponding black hole. The relation between actions via Wick rotation, Hodge
dualisation and analytic continuation of axions is discussed.Comment: 72 pages, 2 figure
Process Calculi Abstractions for Biology
Several approaches have been proposed to model biological systems by means of the formal techniques and tools available in computer science. To mention just a few of them, some representations are inspired by Petri Nets theory, and some other by stochastic processes. A most recent approach consists in interpreting the living entities as terms of process calculi where the behavior of the represented systems can be inferred by applying syntax-driven rules. A comprehensive picture of the state of the art of the process calculi approach to biological modeling is still missing. This paper goes in the direction of providing such a picture by presenting a comparative survey of the process calculi that have been used and proposed to describe the behavior of living entities. This is the preliminary version of a paper that was published in Algorithmic Bioprocesses. The original publication is available at http://www.springer.com/computer/foundations/book/978-3-540-88868-
General instanton counting and 5d SCFT
Instanton partition functions of 5d N=1 gauge theories are Witten indices for
the ADHM gauged quantum mechanics with (0,4) SUSY. We derive the integral
contour prescriptions for these indices using the Jeffrey-Kirwan method, for
gauge theories with hypermultiplets in various representations. The results can
be used to study various 4d/5d/6d QFTs. In this paper, we study 5d SCFTs which
are at the UV fixed points of 5d SYM theories. In particular, we focus on the
Sp(N) theories with N_f \leq 7 fundamental and 1 antisymmetric hypermultiplets,
living on the D4-D8-O8 systems. Their superconformal indices calculated from
instantons all show E_{N_f+1} symmetry enhancements. We also discuss some
aspects of the 6d SCFTs living on the M5-M9 system. It is crucial to understand
the UV incompleteness of the 5d SYM, coming from small instantons in our
problem. We explain in our examples how to fix them. As an aside, we derive the
index for general gauged quantum mechanics with (0,2) SUSY.Comment: 67 pages, 9 figures; v3: minor changes, published versio
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