ar X iv : h ep - t h / 01 05 31 7 v 2 4 A ug 2 00 1 Single - channel correlators and residue calculus

ar X iv : h ep - t h / 01 05 31 7 v 1 3 1 M ay 2 00 1 Single - channel correlators and residue calculus

Some simple (namely, single-channel) correlation functions involving an arbitrary number of fields are computed by means of a direct application of the residue calculus, through partial fraction expansions. Examples are presented in minimal models and parafermionic conformal theories. A generic factorized expression is deduced for the corresponding single-channel structure constants.

ar X iv : h ep - t h / 01 01 05 9 v 2 1 4 M ay 2 00 1

We consider the complex scalar field coupled to background NC U(1) YM and calculate the correlator of two gauge invariant composite operators. We show how the noncommutative gauge invariance is restored for higher correlators (though the Green's function itself is not invariant). It is interesting that the recently discovered noncommutative solitons appear in the calculation.

ar X iv : h ep - t h / 04 05 18 0 v 2 3 A ug 2 00 4 DAMTP

We study four-point correlation functions of 1 2-BPS operators of arbitrary weight for all dimensions d = 3, 4, 5, 6 where superconformal theories exist. Using harmonic superspace techniques, we derive the superconformal Ward identities for these correlators and present them in a universal form. We then solve these identities, employing Jack polynomial expansions. We show that the general solut...

ar X iv : h ep - t h / 01 05 31 8 v 1 3 1 M ay 2 00 1 Trace anomaly for 4 D higher derivative scalar - dilaton theory

Trace anomaly for conformally invariant higher derivative 4D scalar-dilaton theory is obtained by means of calculating divergent part of one-loop effective action for such system. Its applications are briefly mentioned.

ar X iv : h ep - t h / 04 08 12 5 v 1 1 7 A ug 2 00 4 Field theoretic models on covariant quantum spaces