362 research outputs found
A Monte Carlo study of the three-states antiferromagnetic Potts model in two dimensions
Using Monte Carlo methods the author studies the two-dimensional three-stages Potts model with antiferromagnetic nearest neighbours and ferromagnetic next-nearest neighbours couplings on a square lattice. The author focuses on the case with only antiferromagnetic coupling; from the analysis of the data gathered, there is evidence that this system shows critical behaviour only at T=0
Wilson Loops and Chiral Correlators on Squashed Sphere
We study chiral deformations of and supersymmetric
gauge theories obtained by turning on
interactions with the superfield. Using localization, we
compute the deformed gauge theory partition function and the
expectation value of circular Wilson loops on a squashed four-sphere. In
the case of the deformed theory, exact formulas for and
are derived in terms of an underlying interacting matrix model replacing
the free Gaussian model describing the theory. Using the AGT
correspondence, the -deformations are related to the insertions of
commuting integrals of motion in the four-point CFT correlator and chiral
correlators are expressed as -derivatives of the gauge theory partition
function on a finite -background. In the so called Nekrasov-Shatashvili
limit, the entire ring of chiral relations is extracted from the
-deformed Seiberg-Witten curve. As a byproduct of our analysis we
show that gauge theories on rational -backgrounds are dual to
CFT minimal models.Comment: 33 pages, 2 figure, in this version we have added two new references
and a detailed comparison with the results obtained in one of these tw
On the Stability of a Stringy Black Hole
We study the stability under perturbations of a charged four dimensional
stringy black hole arising from gauging a previously studied WZW model. We find
that the black hole is stable only in the extremal case .Comment: 14 pages + 1 figure (not included but available on request
Exotic prepotentials from D(-1)D7 dynamics
We compute the partition functions of D(-1)D7 systems describing the
multi-instanton dynamics of SO(N) gauge theories in eight dimensions. This is
the simplest instance of the so called exotic instantons. In analogy with the
Seiberg-Witten theory in four space-time dimensions, the prepotential and
correlators in the chiral ring are derived via localization formulas and found
to satisfy relations of the Matone type. Exotic prepotentials of SO(N) gauge
theories with N=2 supersymmetries in four-dimensions are also discussed.Comment: 19 page
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