98 research outputs found
Matrix equations and trilinear commutation relations
In this paper we discuss a general algebraic approach to treating static
equations of matrix models with a mass-like term. In this approach the
equations of motions are considered as consequence of parafermi-like trilinear
commutation relations. In this context we consider several solutions, including
construction of noncommutative spheres. The equivalence of fuzzy spheres and
parafermions is underlined.Comment: 10 pages, an incorrect claim is removed, one reference is adde
Dyon Spectrum in Generic N=4 Supersymmetric Z_N Orbifolds
We find the exact spectrum of a class of quarter BPS dyons in a generic N=4
supersymmetric Z_N orbifold of type IIA string theory on K3\times T^2 or T^6.
We also find the asymptotic expansion of the statistical entropy to first
non-leading order in inverse power of charges and show that it agrees with the
entropy of a black hole carrying same set of charges after taking into account
the effect of the four derivative Gauss-Bonnet term in the effective action of
the theory.Comment: LaTeX file, 39 pages; minor change
On Stability of the Three 3-brane Model
We show that the Goldberger-Wise mechanism for the three 3-brane scenario proposed by Kogan et al. stabilizes the radion. We find that the system of 3-branes stabilizes in such a way that the loss in the scale factor is insignificant. That is, the negative tension brane chooses to stay close to the visible brane
Adding Charges to N=4 Dyons
The spectrum of dyons in a class of N=4 supersymmetric string theories has
been found for a specific set of electric and magnetic charge vectors. We
extend the analysis to more general charge vectors by considering various
charge carrying collective excitations of the original system.Comment: LaTeX file, 16 page
Dyon Spectrum in N=4 Supersymmetric Type II String Theories
We compute the spectrum of quarter BPS dyons in freely acting Z_2 and Z_3
orbifolds of type II string theory compactified on a six dimensional torus. For
large charges the result for statistical entropy computed from the degeneracy
formula agrees with the corresponding black hole entropy to first non-leading
order after taking into account corrections due to the curvature squared terms
in the effective action. The result is significant since in these theories the
entropy of a small black hole, computed using the curvature squared corrections
to the effective action, fails to reproduce the statistical entropy associated
with elementary string states.Comment: LaTeX file, 32 pages; v2:minor change
Dyon Spectrum in CHL Models
We propose a formula for the degeneracy of quarter BPS dyons in a class of
CHL models. The formula uses a modular form of a subgroup of the genus two
modular group Sp(2,Z). Our proposal is S-duality invariant and reproduces
correctly the entropy of a dyonic black hole to first non-leading order for
large values of the charges.Comment: LaTeX file, 38 pages, minor changes in section 3.3(v2), minor changes
in introduction, appendix A and C(v3
Stochastic quantization and holographic Wilsonian renormalization group
We study relation between stochastic quantization and holographic Wilsonian
renormalization group flow. Considering stochastic quantization of the boundary
on-shell actions with the Dirichlet boundary condition for certain bulk
gravity theories, we find that the radial flows of double trace deformations in
the boundary effective actions are completely captured by stochastic time
evolution with identification of the radial coordinate `' with the
stochastic time '' as . More precisely, we investigate Langevin
dynamics and find an exact relation between radial flow of the double trace
couplings and 2-point correlation functions in stochastic quantization. We also
show that the radial evolution of double trace deformations in the boundary
effective action and the stochastic time evolution of the Fokker-Planck action
are the same. We demonstrate this relation with a couple of examples:
(minimally coupled)massless scalar fields in and U(1) vector fields in
.Comment: 1+30 pages, a new subsection is added, references are adde
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