167 research outputs found
A Number of Quasi-Exactly Solvable N-body Problems
We present several examples of quasi-exactly solvable -body problems in
one, two and higher dimensions. We study various aspects of these problems in
some detail. In particular, we show that in some of these examples the
corresponding polynomials form an orthogonal set and many of their properties
are similar to those of the Bender-Dunne polynomials. We also discuss QES
problems where the polynomials do not form an orthogonal set.Comment: 17pages, Revtex, no figur
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
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
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
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
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