992 research outputs found
Emergent geometry from q-deformations of N=4 super Yang-Mills
We study BPS states in a marginal deformation of super Yang-Mills on R x S^3
using a quantum mechanical system of q-commuting matrices. We focus mainly on
the case where the parameter q is a root of unity, so that the AdS dual of the
field theory can be associated to an orbifold of AdS_5x S^5. We show that in
the large N limit, BPS states are described by density distributions of
eigenvalues and we assign to these distributions a geometrical spacetime
interpretation. We go beyond BPS configurations by turning on perturbative
non-q-commuting excitations. Considering states in an appropriate BMN limit, we
use a saddle point approximation to compute the BMN energy to all perturbative
orders in the 't Hooft coupling. We also examine some BMN like states that
correspond to twisted sector string states in the orbifold and we show that our
geometrical interpretation of the system is consistent with the quantum numbers
of the corresponding states under the quantum symmetry of the orbifold.Comment: 22 pages, 1 figure. v2: added references. v3:final published versio
Aspects of ABJM orbifolds with discrete torsion
We analyze orbifolds with discrete torsion of the ABJM theory by a finite
subgroup of . Discrete torsion is implemented by
twisting the crossed product algebra resulting after orbifolding. It is shown
that, in general, the order of the cocycle we chose to twist the algebra by
enters in a non trivial way in the moduli space. To be precise, the M-theory
fiber is multiplied by a factor of in addition to the other effects that
were found before in the literature. Therefore we got a
action on the fiber. We present a general
analysis on how this quotient arises along with a detailed analysis of the
cases where is abelian
Recent Improvements inthe Complexity of the Effective Nullstellensatz
We bring up to date the estimates on the complexity of the effective Nullstellensatz and the membership problem
Spin bits at two loops
We consider the Super Yang--Mills/spin system map to construct the SU(2) spin
bit model at the level of two loops in Yang--Mills perturbation theory. The
model describes a spin system with chaining interaction. In the large limit
the model is shown to be reduced to the two loop planar integrable spin chain.Comment: 10 pages, 3 figures, References and Acknowledgements adde
Integrable open spin chains from giant gravitons
We prove that in the presence of a maximal giant graviton state in N=4 SYM,
the states dual to open strings attached to the giant graviton give rise to an
PSU(2,2|4) open spin chain model with integrable boundary conditions in the
SO(6) sector of the spin chain to one loop order.Comment: 18 pages, 2 figures, uses JHEP
Generating-function method for tensor products
This is the first of two articles devoted to a exposition of the
generating-function method for computing fusion rules in affine Lie algebras.
The present paper is entirely devoted to the study of the tensor-product
(infinite-level) limit of fusions rules.
We start by reviewing Sharp's character method. An alternative approach to
the construction of tensor-product generating functions is then presented which
overcomes most of the technical difficulties associated with the character
method. It is based on the reformulation of the problem of calculating tensor
products in terms of the solution of a set of linear and homogeneous
Diophantine equations whose elementary solutions represent ``elementary
couplings''. Grobner bases provide a tool for generating the complete set of
relations between elementary couplings and, most importantly, as an algorithm
for specifying a complete, compatible set of ``forbidden couplings''.Comment: Harvmac (b mode : 39 p) and Pictex; this is a substantially reduced
version of hep-th/9811113 (with new title); to appear in J. Math. Phy
Conformal boundary and geodesics for and the plane wave: Their approach in the Penrose limit
Projecting on a suitable subset of coordinates, a picture is constructed in
which the conformal boundary of and that of the plane wave
resulting in the Penrose limit are located at the same line. In a second line
of arguments all and plane wave geodesics are constructed in
their integrated form. Performing the Penrose limit, the approach of null
geodesics reaching the conformal boundary of to that of the
plane wave is studied in detail. At each point these null geodesics of
form a cone which degenerates in the limit.Comment: some statements refined, chapter 5 rewritten to make it more precise,
some typos correcte
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