13,709 research outputs found
Non-Geometric Vacua of the Heterotic String and Little String Theories
We study a class of 6d non-geometric vacua of the
heterotic string which can be understood as
fibrations of genus-two curves over a complex one-dimensional base. The 6d
theories living on the defects that arise when the
genus-two fiber degenerates at a point of the base are analyzed by dualizing to
F-theory on elliptic K3-fibered non-compact Calabi-Yau threefolds. We consider
all possible degenerations of genus-two curves and systematically attempt to
resolve the singularities of the dual threefolds. As in the analogous
non-geometric vacua of the heterotic string, we find that many
of the resulting dual threefolds contain singularities which do not admit a
crepant resolution. When the singularities can be resolved crepantly, we
determine the emerging effective theories which turn out to be little string
theories at a generic point on their tensor branch. We also observe a form of
duality in which theories living on distinct defects are the same.Comment: 39 pages, 3 figures, and 6 table
Resurgence in complex Chern-Simons theory
We study resurgence properties of partition function of SU(2) Chern-Simons
theory (WRT invariant) on closed three-manifolds. We check explicitly that in
various examples Borel transforms of asymptotic expansions posses expected
analytic properties. In examples that we study we observe that contribution of
irreducible flat connections to the path integral can be recovered from
asymptotic expansions around abelian flat connections. We also discuss
connection to Floer instanton moduli spaces, disk instantons in 2d sigma
models, and length spectra of "complex geodesics" on the A-polynomial curve.Comment: 56 pages, 19 figures. v2: references adde
Conformal field theory, boundary conditions and applications to string theory
This is an introduction to two-dimensional conformal field theory and its
applications in string theory. Modern concepts of conformal field theory are
explained, and it is outlined how they are used in recent studies of D-branes
in the strong curvature regime by means of CFT on surfaces with boundary.Comment: 45 pages, LaTeX2
VOA[_4]
We take a peek at a general program that associates vertex (or, chiral) algebras to smooth 4-manifolds in such a way that operations on algebras mirror gluing operations on 4-manifolds and, furthermore, equivalent constructions of 4-manifolds give rise to equivalences (dualities) of the corresponding algebras
Issues in Topological Gauge Theory
We discuss topological theories, arising from the general
twisted gauge theories. We initiate a program of their study in the
Gromov-Witten paradigm. We re-examine the low-energy effective abelian theory
in the presence of sources and study the mixing between the various
-observables. We present the twisted superfield formalism which makes
duality transformations transparent. We propose a scheme which uniquely fixes
all the contact terms. We derive a formula for the correlation functions of
-observables on the manifolds of generalized simple type for and on some manifolds with . We study the theories with matter
and explore the properties of universal instanton. We also discuss the
compactifications of higher dimensional theories. Some relations to sigma
models of type and are pointed out and exploited.Comment: 72 pp., Harvmac (b) mode, some typos corrected, reference adde
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