M-theory curves from warped AdS6_6 in Type IIB

We establish a close relation between recently constructed AdS$_6$ solutions in Type IIB supergravity, which describe the near-horizon limit of $(p,q)$ 5-brane junctions, and the curves wrapped by M5-branes in the M-theory realization of the 5-brane junctions. This provides a geometric interpretation of various objects appearing in the construction of the Type IIB solutions and a physical interpretation of the regularity conditions. Conversely, the Type IIB solutions provide explicit solutions to the equations defining the M-theory curves associated with $(p,q)$ 5-brane junctions.Comment: 24 page

Supersymmetric D3/D5 for massive defects on curved space

We construct the holographic dual for $\mathcal N=4$ SYM on $\rm S^4$ and $\rm AdS_4$ coupled to massive $\mathcal N=2$ supersymmetric quenched flavor fields on a codimension-1 defect, which is $\rm S^3$ and $\rm AdS_3$, respectively. The holographic description is in terms of a D3/probe D5 brane system. We set up and reduce the BPS equations for D5-brane embeddings with arbitrary supersymmetric deformations and partly solve them at the non-linear level. The remaining equations are solved explicitly in a small-mass expansion. We compute the contribution of the defect fields to the partition function on S$^4$ and compare to a field theory computation using supersymmetric localization, for which we set up the matrix model. Both computations agree, lending strong support to holographic probe brane constructions using D3/D5 configurations in general.Comment: 34 pages, 1 figur

Beyond the unitarity bound in AdS/CFT_(A)dS

In this work we expand on the holographic description of CFTs on de Sitter (dS) and anti-de Sitter (AdS) spacetimes and examine how violations of the unitarity bound in the boundary theory are recovered in the bulk physics. To this end we consider a Klein-Gordon field on AdS_(d+1) conformally compactified such that the boundary is (A)dS_d, and choose masses and boundary conditions such that the corresponding boundary operator violates the CFT unitarity bound. The setup in which the boundary is AdS_d exhibits a particularly interesting structure, since in this case the boundary itself has a boundary. The bulk theory turns out to crucially depend on the choice of boundary conditions on the boundary of the AdS_d slices. Our main result is that violations to the unitarity bound in CFTs on dS_d and AdS_d are reflected in the bulk through the presence of ghost excitations. In addition, analyzing the setup with AdS_d on the boundary allows us to draw conclusions on multi-layered AdS/CFT-type dualities.Comment: 30 pages, 2 figures; reference adde

Jason L. Powell, Social Theory and Aging, Rowman and Littlefield, Lanham, Maryland, 2005, 157 pp., pbk $16.95, ISBN 0 7425 1954 6.

We construct a realistic Supersymmetric Grand Unified Theory of Flavour based on PSL(7)×SO(10), where the quarks and leptons in the 16 of SO(10) are assigned to the complex triplet representation of PSL(7), while the flavons are assigned to a combination of sextets and anti-triplets of PSL(7). Using a D-term vacuum alignment mechanism, we require the flavon sextets of PSL(7) to be aligned along the 3-3 direction leading to the third family Yukawa couplings, while the flavon anti-triplets describe the remaining Yukawa couplings. Other sextets are aligned along the neutrino flavour symmetry preserving directions leading to tri-bimaximal neutrino mixing via a type II see-saw mechanism, with predictions for neutrinoless double beta decay and cosmology. <br/

Neutrino Mass and Mixing with Discrete Symmetry

This is a review article about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of see-saw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A4, S4 and Delta(96).Comment: 99 pages, 13 figures, review article, updated to include the results from the latest global fit

On minimal Type IIB AdS6AdS_6 solutions with commuting 7-branes

We construct Type IIB supergravity solutions with geometry $AdS_6\times S^2$ warped over a disc with two boundary points where 5-branes emerge and punctures with 7-brane monodromy. They describe $(p,q)$ 5-brane junctions with two groups of like-charged external 5-branes that are unconstrained by the $s$-rule and an additional group of constrained 5-branes. The dual 5d SCFTs include various theories discussed previously in the literature. We match SCFT operators with scaling dimension of $\mathcal O(N)$ with their representation in supergravity to support the proposed dualities.Comment: 22 pages, 7 figure

Field Theory on Curved Noncommutative Spacetimes

We study classical scalar field theories on noncommutative curved spacetimes. Following the approach of Wess et al. [Classical Quantum Gravity 22 (2005), 3511 and Classical Quantum Gravity 23 (2006), 1883], we describe noncommutative spacetimes by using (Abelian) Drinfel'd twists and the associated *-products and *-differential geometry. In particular, we allow for position dependent noncommutativity and do not restrict ourselves to the Moyal-Weyl deformation. We construct action functionals for real scalar fields on noncommutative curved spacetimes, and derive the corresponding deformed wave equations. We provide explicit examples of deformed Klein-Gordon operators for noncommutative Minkowski, de Sitter, Schwarzschild and Randall-Sundrum spacetimes, which solve the noncommutative Einstein equations. We study the construction of deformed Green's functions and provide a diagrammatic approach for their perturbative calculation. The leading noncommutative corrections to the Green's functions for our examples are derived.Comment: SIGMA Special Issue on Noncommutative Spaces and Field