504 research outputs found
Attractor Flows from Defect Lines
Deforming a two dimensional conformal field theory on one side of a trivial
defect line gives rise to a defect separating the original theory from its
deformation. The Casimir force between these defects and other defect lines or
boundaries is used to construct flows on bulk moduli spaces of CFTs. It turns
out, that these flows are constant reparametrizations of gradient flows of the
g-functions of the chosen defect or boundary condition. The special flows
associated to supersymmetric boundary conditions in N=(2,2) superconformal
field theories agree with the attractor flows studied in the context of black
holes in N=2 supergravity.Comment: 28 page
A worldsheet extension of O(d,d;Z)
We study superconformal interfaces between N=(1,1) supersymmetric sigma
models on tori, which preserve a u(1)^{2d} current algebra. Their fusion is
non-singular and, using parallel transport on CFT deformation space, it can be
reduced to fusion of defect lines in a single torus model. We show that the
latter is described by a semi-group extension of O(d,d;Q), and that (on the
level of Ramond charges) fusion of interfaces agrees with composition of
associated geometric integral transformations. This generalizes the well-known
fact that T-duality can be geometrically represented by Fourier-Mukai
transformations. Interestingly, we find that the topological interfaces between
torus models form the same semi-group upon fusion. We argue that this
semi-group of orbifold equivalences can be regarded as the \alpha' deformation
of the continuous O(d,d) symmetry of classical supergravity.Comment: 71 pages, 1 figure, minor additions and correction
Edge Dynamics from the Path Integral: Maxwell and Yang-Mills
We derive an action describing edge dynamics on interfaces for gauge theories
(Maxwell and Yang-Mills) using the path integral. The canonical structure of
the edge theory is deduced and the thermal partition function calculated. We
test the edge action in several applications. For Maxwell in Rindler space, we
recover earlier results, now embedded in a dynamical canonical framework. A
second application is 2d Yang-Mills theory where the boundary action becomes
just the particle-on-a-group action. Correlators of boundary-anchored Wilson
lines in 2d Yang-Mills are matched with, and identified as correlators of
bilocal operators in the particle-on-a-group edge model.Comment: 50 pages, v2: typos corrected and references added, matches published
versio
Modular Invariance and the Odderon
We identify a new symmetry for the equations governing odderon amplitudes,
corresponding in the Regge limit of QCD to the exchange of 3 reggeized gluons.
The symmetry is a modular invariance with respect to the unique normal subgroup
of sl(2,Z) {\,} of index 2.
This leads to a natural description of the Hamiltonian and conservation-law
operators as acting on the moduli space of elliptic curves with a fixed
``sign'': elliptic curves are identified if they can be transformed into each
other by an {\em even} number of Dehn twists.Comment: 9 pages, LaTeX, uses amssym.def for \Bbb 'blackboard math' font
Knitting Wormholes by Entanglement in Supergravity
We construct a single-boundary wormhole geometry in type IIB supergravity by
perturbing two stacks of extremal D3-branes in the decoupling limit. The
solution interpolates from a two-sided planar AdS-Schwarzschild geometry in the
interior, through a harmonic two-center solution in the intermediate region, to
an asymptotic AdS space. The construction involves a CPT twist in the gluing of
the wormhole to the exterior throats that gives a global monodromy to some
coordinates, while preserving orientability. The geometry has a dual
interpretation in Super Yang-Mills theory in terms of
a Higgsed theory in which
degrees of freedom in each sector are entangled in an approximate
thermofield double state at a temperature much colder than the Higgs scale. We
argue that the solution can be made long-lived by appropriate choice of
parameters, and comment on mechanisms for generating traversability. We also
describe a construction of a double wormhole between two universes.Comment: 34 + 4 pages, 6 figures, added sections and discussion on global
structure of the solution and a double wormhole constructio
- …