1,624 research outputs found

### Six-dimensional D_N theory and four-dimensional SO-USp quivers

We realize four-dimensional N=2 superconformal quiver gauge theories with
alternating SO and USp gauge groups as compactifications of the six-dimensional
D_N theory with defects. The construction can be used to analyze infinitely
strongly-coupled limits and S-dualities of such gauge theories, resulting in a
new class of isolated four-dimensional N=2 superconformal field theories with
SO(2N)^3 flavor symmetry.Comment: 30 pages, 12 figures; v2: published versio

### Surface Operators in N=2 4d Gauge Theories

N=2 four dimensional gauge theories admit interesting half BPS surface
operators preserving a (2,2) two dimensional SUSY algebra. Typical examples are
(2,2) 2d sigma models with a flavor symmetry which is coupled to the 4d gauge
fields. Interesting features of such 2d sigma models, such as (twisted) chiral
rings, and the tt* geometry, can be carried over to the surface operators, and
are affected in surprising ways by the coupling to 4d degrees of freedom. We
will describe in detail a relation between the parameter space of twisted
couplings of the surface operator and the Seiberg-Witten geometry of the bulk
theory. We will discuss a similar result about the tt* geometry of the surface
operator. We will predict the existence and general features of a wall-crossing
formula for BPS particles bound to the surface operator.Comment: 25 pages, 4 figure

### Solving Open String Field Theory with Special Projectors

Schnabl recently found an analytic expression for the string field tachyon
condensate using a gauge condition adapted to the conformal frame of the sliver
projector. We propose that this construction is more general. The sliver is an
example of a special projector, a projector such that the Virasoro operator
\L_0 and its BPZ adjoint \L*_0 obey the algebra [\L_0, \L*_0] = s (\L_0 +
\L*_0), with s a positive real constant. All special projectors provide abelian
subalgebras of string fields, closed under both the *-product and the action of
\L_0. This structure guarantees exact solvability of a ghost number zero string
field equation. We recast this infinite recursive set of equations as an
ordinary differential equation that is easily solved. The classification of
special projectors is reduced to a version of the Riemann-Hilbert problem, with
piecewise constant data on the boundary of a disk.Comment: 64 pages, 6 figure

### N=2 SU Quiver with USP Ends or SU Ends with Antisymmetric Matter

We consider the four dimensional scale invariant N=2 SU quiver gauge theories
with USp(2N) ends or SU(2N) ends with antisymmetric matter representations. We
argue that these theories are realized as six dimensional A_{2N-1} (0,2)
theories compactified on spheres with punctures. With this realization, we can
study various strongly coupled cusps in moduli space and find the S-dual
theories. We find a class of isolated superconformal field theories with only
odd dimensional operators $D(\phi)\geq3$ and superconformal field theories with
only even dimensional operators $D(\phi)\geq4$.Comment: Minor changes are made; refrences are added; 21 pages, 18 figure

### Note on Generalized Janus Configurations

We study several aspects of generalized Janus configuration, which includes a
theta term. We investigate the vacuum structure of the theory and find that
unlike the Janus configuration without theta term there is no nontrivial
vacuum. We also discuss BPS soliton configuration both by supersymmetry
analysis and from energy functional. The half BPS configurations could be
realized by introducing transverse (p,q)-strings in original brane
configuration corresponding to generalized Janus configuration. It turns out
the BPS soliton could be taken as modified dyon. We discuss the solution of
half BPS equations for the sharp interface case. Moreover we construct less
supersymmetric Janus configuration with theta term.Comment: 27 pages; References adde

### The elliptic genus from split flows and Donaldson-Thomas invariants

We analyze a mixed ensemble of low charge D4-D2-D0 brane states on the
quintic and show that these can be successfully enumerated using attractor flow
tree techniques and Donaldson-Thomas invariants. In this low charge regime one
needs to take into account worldsheet instanton corrections to the central
charges, which is accomplished by making use of mirror symmetry. All the
charges considered can be realized as fluxed D6-D2-D0 and anti-D6-D2-D0 pairs
which we enumerate using DT invariants. Our procedure uses the low charge
counterpart of the picture developed Denef and Moore. By establishing the
existence of flow trees numerically and refining the index factorization
scheme, we reproduce and improve some results obtained by Gaiotto, Strominger
and Yin. Our results provide appealing evidence that the strong split flow tree
conjecture holds and allows to compute exact results for an important sector of
the theory. Our refined scheme for computing indices might shed some light on
how to improve index computations for systems with larger charges.Comment: 37 pages, 12 figure

### Boundary and Midpoint Behaviors of Lump Solutions in Vacuum String Field Theory

We discuss various issues concerning the behaviors near the boundary
(\sigma=0,\pi) and the midpoint (\sigma=\pi/2) of the open string coordinate
X(\sigma) and its conjugate momentum P(\sigma)=-i\delta/\delta X(\sigma) acting
on the matter projectors of vacuum string field theory. Our original interest
is in the dynamical change of the boundary conditions of the open string
coordinate from the Neumann one in the translationally invariant backgrounds to
the Dirichlet one in the D-brane backgrounds. We find that the Dirichlet
boundary condition is realized on a lump solution only partially and only when
its parameter takes a special value. On the other hand, the string midpoint has
a mysterious property: it obeys the Neumann (Dirichlet) condition in the
translationally invariant (lump) background.Comment: 23 pages, no figures, LaTeX2e, a reference adde

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