300 research outputs found
Large N Free Energy of 3d N=4 SCFTs and AdS/CFT
We provide a non-trivial check of the AdS_4/CFT_3 correspondence recently
proposed in arXiv:1106.4253 by verifying the GKPW relation in the large N
limit. The CFT free energy is obtained from the previous works
(arXiv:1105.2551, arXiv:1105.4390) on the S^3 partition function for
3-dimensional N=4 SCFT T[SU(N)]. This is matched with the computation of the
type IIB action on the corresponding gravity background. We unexpectedly find
that the leading behavior of the free energy at large N is 1/2 N^2 ln N. We
also extend our results to richer theories and argue that 1/2 N^2 ln N is the
maximal free energy at large N in this class of gauge theories.Comment: 20 pages, 3 figure
Conformal Aspects of Spinor-Vector Duality
We present a detailed study of various aspects of Spinor-Vector duality in
Heterotic string compactifications and expose its origin in terms of the
internal conformal field theory. In particular, we illustrate the main features
of the duality map by using simple toroidal orbifolds preserving N_4 = 1 and
N_4 = 2 spacetime supersymmetries in four dimensions. We explain how the
duality map arises in this context by turning on special values of the Wilson
lines around the compact cycles of the manifold. We argue that in models with
N_4 = 2 spacetime supersymmetry, the interpolation between the Spinor-Vector
dual vacua can be continuously realized. We trace the origin of the
Spinor-Vector duality map to the presence of underlying N = (2, 2) and N = (4,
4) SCFTs, and explicitly show that the induced spectral-flow in the twisted
sectors is responsible for the observed duality. The isomorphism between
current algebra representations gives rise to a number of chiral character
identities, reminiscent of the recently-discovered MSDS symmetry.Comment: 49 page
Classification of Heterotic Pati-Salam Models
We extend the classification of free fermionic heterotic-string models to
vacua in which the SO(10) GUT symmetry is broken at the string level to the
Pati-Salam subgroup. Using our classification method we recently presented the
first example of a quasi--realistic heterotic-string vacuum that is free of
massless exotic states. Within this method we are able to derive algebraic
expressions for the generalised GSO projections for all sectors that appear in
the models. This facilitates the programming of the entire spectrum analysis in
a computer code. The total number of vacua in the class of models that we
classify is 2^{51} ~ 10^{15}. We perform a statistical sampling in this space
of models and extract 10^{11} distinct configurations with Pati-Salam gauge
group. Our results demonstrate that one in every 10^{6} vacua correspond to a
three generation exophobic model with the required Higgs states, needed to
induce spontaneous breaking to the Standard Model.Comment: 42 pages. 6 figures. Published version. Added acknowledgement
Simple holographic duals to boundary CFTs
By relaxing the regularity conditions imposed in arXiv:1107.1722 on half-BPS
solutions to six-dimensional Type~4b supergravity, we enlarge the space of
solutions to include two new half-BPS configurations, which we refer to as the
\kap\ and the \funnel. We give evidence that the \kap\ and \funnel\ can be
interpreted as fully back-reacted brane solutions with respectively and
world volumes. \kap\ and \funnel\ solutions with a single
asymptotic region are constructed analytically. We argue
that \kap\ solutions provide simple examples of holographic duals to boundary
CFTs in two dimensions and present calculations of their holographic boundary
entropy to support the BCFT dual picture.Comment: 37 pages, pdflatex, 5 figure
Homeostatic maintenance and age-related functional decline in the Drosophila ear
Age-related hearing loss (ARHL) is a threat to future human wellbeing. Multiple factors contributing to the terminal auditory decline have been identified; but a unified understanding of ARHL - or the homeostatic maintenance of hearing before its breakdown - is missing. We here present an in-depth analysis of homeostasis and ageing in the antennal ears of the fruit fly Drosophila melanogaster. We show that Drosophila, just like humans, display ARHL. By focusing on the phase of dynamic stability prior to the eventual hearing loss we discovered a set of evolutionarily conserved homeostasis genes. The transcription factors Onecut (closest human orthologues: ONECUT2, ONECUT3), Optix (SIX3, SIX6), Worniu (SNAI2) and Amos (ATOH1, ATOH7, ATOH8, NEUROD1) emerged as key regulators, acting upstream of core components of the fly's molecular machinery for auditory transduction and amplification. Adult-specific manipulation of homeostatic regulators in the fly's auditory neurons accelerated - or protected against - ARHL
Holographic renormalization and supersymmetry
Holographic renormalization is a systematic procedure for regulating
divergences in observables in asymptotically locally AdS spacetimes. For dual
boundary field theories which are supersymmetric it is natural to ask whether
this defines a supersymmetric renormalization scheme. Recent results in
localization have brought this question into sharp focus: rigid supersymmetry
on a curved boundary requires specific geometric structures, and general
arguments imply that BPS observables, such as the partition function, are
invariant under certain deformations of these structures. One can then ask if
the dual holographic observables are similarly invariant. We study this
question in minimal N = 2 gauged supergravity in four and five dimensions. In
four dimensions we show that holographic renormalization precisely reproduces
the expected field theory results. In five dimensions we find that no choice of
standard holographic counterterms is compatible with supersymmetry, which leads
us to introduce novel finite boundary terms. For a class of solutions
satisfying certain topological assumptions we provide some independent tests of
these new boundary terms, in particular showing that they reproduce the
expected VEVs of conserved charges.Comment: 70 pages; corrected typo
Chiral primary one-point functions in the D3-D7 defect conformal field theory
JHEP is an open-access journal funded by SCOAP3 and licensed under CC BY 4.0archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2012-81 slaccitation: %%CITATION = ARXIV:1210.7015;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: NORDITA-2012-81 slaccitation: %%CITATION = ARXIV:1210.7015;%%C.F.K. and D.Y. were supported in part by FNU through grant number 272-08-0329.
G.W.S. is supported by NSERC of Canada and by the Villum foundation through their
Velux Visiting Professor program
Exophobic Quasi-Realistic Heterotic String Vacua
We demonstrate the existence of heterotic-string vacua that are free of
massless exotic fields. The need to break the non-Abelian GUT symmetries in k=1
heterotic-string models by Wilson lines, while preserving the GUT embedding of
the weak-hypercharge and the GUT prediction sin^2\theta_w(M(GUT))=3/8,
necessarily implies that the models contain states with fractional electric
charge. Such states are severely restricted by observations, and must be
confined or sufficiently massive and diluted. We construct the first
quasi-realistic heterotic-string models in which the exotic states do not
appear in the massless spectrum, and only exist, as they must, in the massive
spectrum. The SO(10) GUT symmetry is broken to the Pati-Salam subgroup. Our PS
heterotic-string models contain adequate Higgs representations to break the GUT
and electroweak symmetry, as well as colour Higgs triplets that can be used for
the missing partner mechanism. By statistically sampling the space of
Pati-Salam vacua we demonstrate the abundance of quasi--realistic three
generation models that are completely free of massless exotics, rendering it
plausible that obtaining realistic Yukawa couplings may be possible in this
space of models.Comment: 14 pages. Standard LaTex. 1 figure. 2 tables. Typos correcte
Investigation of Quasi--Realistic Heterotic String Models with Reduced Higgs Spectrum
Quasi--realistic heterotic-string models in the free fermionic formulation
typically contain an anomalous U(1), which gives rise to a Fayet-Iliopolous
term that breaks supersymmetry at the one--loop level in string perturbation
theory. Supersymmetry is restored by imposing F- and D-flatness on the vacuum.
In Phys. Rev. D 78 (2008) 046009, we presented a three generation free
fermionic standard-like model which did not admit stringent F- and D-flat
directions, and argued that the all the moduli in the model are fixed. The
particular property of the model was the reduction of the untwisted Higgs
spectrum by a combination of symmetric and asymmetric boundary conditions with
respect to the internal fermions associated with the compactified dimensions.
In this paper we extend the analysis of free fermionic models with reduced
Higgs spectrum to the cases in which the SO(10) symmetry is left unbroken, or
is reduced to the flipped SU(5) subgroup. We show that all the models that we
study in this paper do admit stringent flat directions. The only examples of
models that do not admit stringent flat directions remain the strandard-like
models of reference Phys. Rev. D 78 (2008) 046009.Comment: 38 pages, 1 figur
Phases of planar 5-dimensional supersymmetric Chern-Simons theory
In this paper we investigate the large- behavior of 5-dimensional
super Yang-Mills with a level Chern-Simons term and an
adjoint hypermultiplet. As in three-dimensional Chern-Simons theories, one must
choose an integration contour to completely define the theory. Using
localization, we reduce the path integral to a matrix model with a cubic action
and compute its free energy in various scenarios. In the limit of infinite
Yang-Mills coupling and for particular choices of the contours, we find that
the free-energy scales as for gauge groups with large values
of the Chern-Simons 't\,Hooft coupling, . If we also
set the hypermultiplet mass to zero, then this limit is a superconformal fixed
point and the behavior parallels other fixed points which have known
supergravity duals. We also demonstrate that gauge groups cannot have
this scaling for their free-energy. At finite Yang-Mills coupling we
establish the existence of a third order phase transition where the theory
crosses over from the Yang-Mills phase to the Chern-Simons phase. The phase
transition exists for any value of , although the details differ
between small and large values of . For pure Chern-Simons
theories we present evidence for a chain of phase transitions as
is increased.
We also find the expectation values for supersymmetric circular Wilson loops
in these various scenarios and show that the Chern-Simons term leads to
different physical properties for fundamental and anti-fundamental Wilson
loops. Different choices of the integration contours also lead to different
properties for the loops.Comment: 40 pages, 17 figures, Minor corrections, Published versio
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