282 research outputs found
N=2 Generalized Superconformal Quiver Gauge Theory
Four dimensional N=2 generalized superconformal field theory can be defined
by compactifying six dimensional (0,2) theory on a Riemann surface with regular
punctures. In previous studies, gauge coupling constant space is identified
with the moduli space of punctured Riemann surface M_{g,n}. We show that the
weakly coupled gauge group description corresponds to a stable nodal curve, and
the coupling space is actually the Deligne-Mumford compactification
\bar{M}_{g,n}. We also give an algorithm to determine the weakly coupled gauge
group and matter content in any duality frame.Comment: v2, reorganizing the materials, discussions on 2d CFT is remove
M-theory Inspired No-scale Supergravity
We propose a supergravity model that contains elements recently shown to
arise in the strongly-coupled limit of the heterotic string
(M-theory), including a no-scale--like K\"ahler potential, the identification
of the string scale with the gauge coupling unification scale, and the onset of
supersymmetry breaking at an intermediate scale determined by the size of the
eleventh dimension of M-theory. We also study the phenomenological consequences
of such scenario, which include a rather constrained sparticle spectrum within
the reach of present-generation particle accelerators.Comment: 8 pages, LaTeX, 3 figures (included
Non-Abelian Flat Directions in a Minimal Superstring Standard Model
Recently, by studying exact flat directions of non-Abelian singlet fields, we
demonstrated the existence of free fermionic heterotic-string models in which
the SU(3)_C x SU(2)_L x U(1)_Y-charged matter spectrum, just below the string
scale, consists solely of the MSSM spectrum. In this paper we generalize the
analysis to include VEVs of non-Abelian fields. We find several,
MSSM-producing, exact non-Abelian flat directions, which are the first such
examples in the literature. We examine the possibility that hidden sector
condensates lift the flat directions.Comment: 14 pages. Standard Late
Toward the M(F)--Theory Embedding of Realistic Free-Fermion Models
We construct a Landau-Ginzburg model with the same data and symmetries as a
orbifold that corresponds to a class of realistic free-fermion
models. Within the class of interest, we show that this orbifolding connects
between different orbifold models and commutes with the mirror
symmetry. Our work suggests that duality symmetries previously discussed in the
context of specific and theory compactifications may be extended to the
special orbifold that characterizes realistic free-fermion
models.Comment: 15 pages. Standard Late
More Three Dimensional Mirror Pairs
We found a lot of new three dimensional N = 4 mirror pairs generalizing
previous considerations on three dimensional generalized quiver gauge theories.
We recovered almost all previous discovered mirror pairs with these
constructions. One side of these mirror pairs are always the conventional
quiver gauge theories. One of our result can also be used to determine the
matter content and weakly coupled gauge groups of four dimensional N = 2
generalized quiver gauge theories derived from six dimensional A_N and D_N
theory, therefore we explicitly constructed four dimensional S-duality pairs.Comment: 33 pages, 18 figures version2 minor correction
Decoherent Scattering of Light Particles in a D-Brane Background
We discuss the scattering of two light particles in a D-brane background. It
is known that, if one light particle strikes the D brane at small impact
parameter, quantum recoil effects induce entanglement entropy in both the
excited D brane and the scattered particle. In this paper we compute the
asymptotic `out' state of a second light particle scattering off the D brane at
large impact parameter, showing that it also becomes mixed as a consequence of
quantum D-brane recoil effects. We interpret this as a non-factorizing
contribution to the superscattering operator S-dollar for the two light
particles in a Liouville D-brane background, that appears when quantum D-brane
excitations are taken into account.Comment: 18 pages LATEX, one figure (incorporated
N=2 S-duality via Outer-automorphism Twists
Compactification of 6d N=(2,0) theory of type G on a punctured Riemann
surface has been effectively used to understand S-dualities of 4d N=2 theories.
We can further introduce branch cuts on the Riemann surface across which the
worldvolume fields are transformed by the discrete symmetries associated to
those of the Dynkin diagram of type G. This allows us to generate more
S-dualities, and in particular to reproduce a couple of S-dual pairs found
previously by Argyres and Wittig.Comment: 8 pages, 6 figure
Hitchin Equation, Singularity, and N=2 Superconformal Field Theories
We argue that Hitchin's equation determines not only the low energy effective
theory but also describes the UV theory of four dimensional N=2 superconformal
field theories when we compactify six dimensional theory on a
punctured Riemann surface. We study the singular solution to Hitchin's equation
and the Higgs field of solutions has a simple pole at the punctures; We show
that the massless theory is associated with Higgs field whose residual is a
nilpotent element; We identify the flavor symmetry associated with the puncture
by studying the singularity of closure of the moduli space of solutions with
the appropriate boundary conditions. For the mass-deformed theory the residual
of the Higgs field is a semi-simple element, we identify the semi-simple
element by arguing that the moduli space of solutions of mass-deformed theory
must be a deformation of the closure of the moduli space of the massless
theory. We also study the Seiberg-Witten curve by identifying it as the
spectral curve of the Hitchin's system. The results are all in agreement with
Gaiotto's results derived from studying the Seiberg-Witten curve of four
dimensional quiver gauge theory.Comment: 42 pages, 20 figures, Hitchin's equation for N=2 theory is derived by
comparing different order of compactification of six dimensional theory on
T^2\times \Sigma. More discussion about flavor symmetries. Typos are
correcte
Nilpotent orbits and codimension-two defects of 6d N=(2,0) theories
We study the local properties of a class of codimension-2 defects of the 6d
N=(2,0) theories of type J=A,D,E labeled by nilpotent orbits of a Lie algebra
\mathfrak{g}, where \mathfrak{g} is determined by J and the outer-automorphism
twist around the defect. This class is a natural generalisation of the defects
of the 6d theory of type SU(N) labeled by a Young diagram with N boxes. For any
of these defects, we determine its contribution to the dimension of the Higgs
branch, to the Coulomb branch operators and their scaling dimensions, to the 4d
central charges a and c, and to the flavour central charge k.Comment: 57 pages, LaTeX2
Penner Type Matrix Model and Seiberg-Witten Theory
We discuss the Penner type matrix model recently proposed by Dijkgraaf and
Vafa for a possible explanation of the relation between four-dimensional gauge
theory and Liouville theory by making use of the connection of the matrix model
to two-dimensional CFT. We first consider the relation of gauge couplings
defined in UV and IR regimes of N_f = 4, N = 2 supersymmetric gauge theory
being related as . We then use this relation to discuss the action of modular
transformation on the matrix model and determine its spectral curve.
We also discuss the decoupling of massive flavors from the N_f = 4 matrix
model and derive matrix models describing asymptotically free N = 2 gauge
theories. We find that the Penner type matrix theory reproduces correctly the
standard results of N = 2 supersymmetric gauge theories.Comment: 22 pages; v2: references added, typos corrected; v3: a version to
appear in JHE
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