6 research outputs found
Four-loop anomalous dimensions in Leigh-Strassler deformations
We determine the scalar part of the four-loop chiral dilatation operator for
Leigh-Strassler deformations of N=4 super Yang-Mills. This is sufficient to
find the four-loop anomalous dimensions for operators in closed scalar
subsectors. This includes the SU(2) subsector of the (complex)
beta-deformation, where we explicitly compute the anomalous dimension for
operators with a single impurity. It also includes the "3-string null"
operators of the cubic Leigh-Strassler deformation. Our four-loop results show
that the rational part of the anomalous dimension is consistent with a
conjecture made in arXiv:1108.1583 based on the three-loop result of
arXiv:1008.3351 and the N=4 magnon dispersion relation. Here we find additional
zeta(3) terms.Comment: Latex, feynmp, 21 page
Intersecting Flavor Branes
We consider an instance of the AdS/CFT duality where the bulk theory contains
an open string tachyon, and study the instability from the viewpoint of the
boundary field theory. We focus on the specific example of the AdS_5 X S^5
background with two probe D7 branes intersecting at general angles. For generic
angles supersymmetry is completely broken and there is an open string tachyon
between the branes. The field theory action for this system is obtained by
coupling to N =4 super Yang-Mills two N =2 hyper multiplets in the fundamental
representation of the SU(N) gauge group, but with different choices of
embedding of the two N=2 subalgebras into N=4. On the field theory side we find
a one-loop Coleman-Weinberg instability in the effective potential for the
fundamental scalars. We identify a mesonic operator as the dual of the open
string tachyon. By AdS/CFT, we predict the tachyon mass for small 't Hooft
coupling (large bulk curvature) and confirm that it violates the AdS stability
bound.Comment: 36 page
On non-supersymmetric conformal manifolds: field theory and holography
We discuss the constraints that a conformal field theory should enjoy to admit exactly marginal deformations, i.e. to be part of a conformal manifold. In particular, using tools from conformal perturbation theory, we derive a sum rule from which one can extract restrictions on the spectrum of low spin operators and on the behavior of OPE coefficients involving nearly marginal operators. We then consider conformal field theories admitting a gravity dual description, and as such a large- expansion. We discuss the relation between conformal perturbation theory and loop expansion in the bulk, and show how such connection could help in the search for conformal manifolds beyond the planar
limit. Our results do not rely on supersymmetry, and therefore apply also outside the realm of superconformal field theories