19 research outputs found
Interaction of non-parallel D1-branes
We find the potential per unit length between two non-intersecting D1-branes
as a function of their relative angle.Comment: 10 pages, LaTex, no figure
The IR/UV Connection in the Non-Commutative Gauge Theories
Quantum field theory on non-commutative spaces does not enjoy the usual
ultraviolet-infrared decoupling that forms the basis for conventional
renormalization. The high momentum contributions to loop integrations can lead
to unfamiliar long distance behavior which can potentially undermine naive
expectations for the IR behavior of the theory. These "anomalies" involve
non-analytic behavior in the noncommutativity parameter Theta making the limit
Theta goes to zero singular.
In this paper we will analyze such effects in the one loop approximation to
gauge theories on non-commutative space. We will see that contrary to
expectations poles in Theta do occur and lead to large discrepancies between
the expected and actual infrared behavior. We find that poles in Theta are
absent in supersymmetric theories. The "anomalies" are generally still present,
but only at the logarithmic level. A notable exception is non-commutative super
Yang Mills theory with 16 real supercharges in which anomalous effects seem to
be absent altogether.Comment: 17 pages, 7 figures, Appendi
Comments on 4-point functions in the CFT/AdS correspondence
We study the four--point function of chiral primaries corresponding to the
dilaton--axion sector in supergravity in the /CFT correspondence. We
find relations between some of the supergravity graphs and compute their
leading singularities. We discuss the issue of logarithmic singularities and
their significance for the OPE structure of the CFT.Comment: Latex, 12 pages, Some typos correcte
The Operator Product Expansion of N=4 SYM and the 4-point Functions of Supergravity
We give a detailed Operator Product Expansion interpretation of the results
for conformal 4-point functions computed from supergravity through the AdS/CFT
duality. We show that for an arbitrary scalar exchange in AdS(d+1) all the
power-singular terms in the direct channel limit (and only these terms) exactly
match the corresponding contributions to the OPE of the operator dual to the
exchanged bulk field and of its conformal descendents. The leading logarithmic
singularities in the 4-point functions of protected N=4 super-Yang Mills
operators (computed from IIB supergravity on AdS(5) X S(5) are interpreted as
O(1/N^2) renormalization effects of the double-trace products appearing in the
OPE. Applied to the 4-point functions of the operators Ophi ~ tr F^2 + ... and
Oc ~ tr FF~ + ..., this analysis leads to the prediction that the double-trace
composites [Ophi Oc] and [Ophi Ophi - Oc Oc] have anomalous dimension -16/N^2
in the large N, large g_{YM}^2 N limit. We describe a geometric picture of the
OPE in the dual gravitational theory, for both the power-singular terms and the
leading logarithms. We comment on several possible extensions of our results.Comment: 42 page