Mihail Mihailescu

Evaluation of glueball masses from supergravity

In the framework of the conjectured duality relation between large {ital N} gauge theory and supergravity the spectra of masses in large {ital N} gauge theory can be determined by solving certain eigenvalue problems in supergravity. In this paper we study the eigenmass problem given by Witten as a possible approximation for masses in QCD without supersymmetry. We place a particular emphasis on the treatment of the horizon and related boundary conditions. We construct exact expressions for the analytic expansions of the wave functions both at the horizon and at infinity and show that requiring smoothness at the horizon and normalizability gives a well defined eigenvalue problem. We show, for example, that there are no smooth solutions with a vanishing derivative at the horizon. The mass eigenvalues up to m{sup 2}=1000 corresponding to smooth normalizable wave functions are presented. We comment on the relation of our work with the results found in a recent paper by C. Cs{acute a}ki {ital et al.}, hep-th/9806021, which addresses the same problem. {copyright} {ital 1998} {ital The American Physical Society}

Lumps and p branes in open string field theory

Abstract We describe numerical methods for constructing lump solutions in open string field theory. According to Sen, these lumps represent lower dimensional Dp branes and numerical evaluation of their energy can be compared with the expected value for the tension. We take particular care of all higher derivative terms inherent in Wittens version of open string field theory. The importance of these terms for off shell phenomena is argued in the text. Detailed numerical calculations done for the case of general p brane show very good agreement with Sens conjectured value. This gives credence to the conjecture itself and establishes further the usefulness of Wittens version of SFT.

Gravity from CFT on SN(X) : symmetries and interactions

The orbifold CFT dual to string theory on

Correlation functions for chiral primaries in D = 6 supergravity on AdS3 × S3

ADS_3 \times S^3

Noncommutative spheres and the AdS/CFT correspondence

allows a construction of gravitational actions based on collective field techniques. We describe a fundamental role played by a Lie algebra constructed from chiral primaries and their CFT conjugates. The leading terms in the algebra at large

Non-BPS branes on a Calabi-Yau threefold and Bose-Fermi degeneracy

N

Large N field theory of N=2 strings and self-dual gravity

are derived from the computation of chiral primary correlation functions. The algebra is argued to determine the dynamics of the theory, its representations provide free and interacting hamiltonians for chiral primaries. This dynamics is seen to be given by an effective one plus one dimensional field theory. The structure of the algebra and its representations shows qualitatively new features associated with thresholds at

Large N WZW field theory of N=2 strings

L_0= N

Duality and combinatorics of long strings in ADS3

,

Hidden classical symmetry in quantum spaces at roots of unity : From q-sphere to fuzzy sphere

L_0 = N/2