38 research outputs found
Brane Inflation and Moduli Stabilization on Twisted Tori
We consider supergravity compactifications on 6-dimensional twisted tori,
which are 5-torus fibrations of the circle. The motion of branes on such
manifolds can lead to power-law potentials at low energy, that may be useful
for inflation. We classify the possible low energy potentials one can obtain by
wrapping branes on different cycles of the fibre. Turning to the problem of
moduli stabilization in such models, we prove a no-go result for solutions with
parametrically small cosmological constant, under certain assumptions for the
orientifolds and D-branes. We also consider the role of discrete Wilson lines
in moduli stabilization on general closed manifolds, and show that gauge
invariance restricts their contributions to the effective potential. We derive
the allowed discrete Wilson lines in massive Type IIA supergravity on twisted
tori. We conclude with a detailed example, computing the effective potentials
in a class of models involving a twisted torus and an orientifold 6-plane.Comment: 31+20 pages. v2: added references. v3: JHEP versio
Three Dimensional Bosonization From Supersymmetry
Three dimensional bosonization is a conjectured duality between
non-supersymmetric Chern-Simons theories coupled to matter fields in the
fundamental representation of the gauge group. There is a well-established
supersymmetric version of this duality, which involves Chern-Simons theories
with supersymmetry coupled to fundamental chiral multiplets.
Assuming that the supersymmetric duality is valid, we prove that
non-supersymmetric bosonization holds for all planar correlators of
single-trace operators. The main tool we employ is a double-trace flow from the
supersymmetric theory to an IR fixed point, in which the scalars and fermions
are effectively decoupled in the planar limit. A generalization of this
technique can be used to derive the duality mapping of all renormalizable
couplings, in non-supersymmetric theories with both a scalar and a fermion. Our
results do not rely on an explicit computation of planar diagrams.Comment: 39 pages, 3 figures. v2: added reference
The Holographic Dictionary for Beta Functions of Multi-trace Coupling Constants
Field theories with weakly coupled holographic duals, such as large N gauge
theories, have a natural separation of their operators into `single-trace
operators' (dual to single-particle states) and `multi-trace operators' (dual
to multi-particle states). There are examples of large N gauge theories where
the beta functions of single-trace coupling constants all vanish, but marginal
multi-trace coupling constants have non-vanishing beta functions that spoil
conformal invariance (even when all multi-trace coupling constants vanish). The
holographic dual of such theories should be a classical solution in anti-de
Sitter space, in which the boundary conditions that correspond to the
multi-trace coupling constants depend on the cutoff scale, in a way that spoils
conformal invariance. We argue that this is realized through specific bulk
coupling constants that lead to a running of the multi-trace coupling
constants. This fills a missing entry in the holographic dictionary.Comment: 31 pages. v2: added references. v3: added references, JHEP versio
The Thermal Free Energy in Large N Chern-Simons-Matter Theories
We compute the thermal free energy in large N U(N) Chern-Simons-matter
theories with matter fields (scalars and/or fermions) in the fundamental
representation, in the large temperature limit. We note that in these theories
the eigenvalue distribution of the holonomy of the gauge field along the
thermal circle does not localize even at very high temperatures, and this
affects the computation significantly. We verify that our results are
consistent with the conjectured dualities between Chern-Simons-matter theories
with scalar fields and with fermion fields, as well as with the strong-weak
coupling duality of the N=2 supersymmetric Chern-Simons-matter theory.Comment: 41 pages, 8 figures. v2: minor corrections, added references. v3:
added pdfoutpu
Classification of Energy Flow Observables in Narrow Jets
We present a classification of energy flow variables for highly collimated
jets. Observables are constructed by taking moments of the energy flow and
forming scalars of a suitable Lorentz subgroup. The jet shapes are naturally
arranged in an expansion in both angular and energy resolution, allowing us to
derive the natural observables for describing an N-particle jet. We classify
the leading variables that characterize jets with up to 4 particles. We
rediscover the familiar jet mass, angularities, and planar flow, which dominate
the lowest order substructure variables. We also discover several new
observables and we briefly discuss their physical interpretation.Comment: 11 pages and 1 figur