Supergravity and "New" Six-Dimensional Gauge Theories

In the first part of this letter, we analyse the supergravity dual descriptions of six-dimensional field theories realized on the worldvolume of (p,q) five-branes (OD5 theory). We show that in order for the low-energy gauge theory description to be valid the theta parameter must be rational. Irrational values of theta require a strongly coupled string description of the system at low-energy. We discuss the phase structure and deduce some properties of these theories. In the second part we construct and study the supergravity description of NS5-branes with two electric RR field, which provides a dual description of six-dimensional theories with several light open D-brane excitations.Comment: 13 pages, latex; numerical coefficients fixed, conclusions unchanged, ref. adde

On Type II NS5-branes in the presence of an RR field

In this letter we use Type II NS5-branes in the presence of an RR field at the decoupling limit to study a non-commutative version of little string theory. We shall see that the decoupling limit of NS5-branes in the presence of an RR field is completely different from the one we had in ordinary little string theory; in particular for Type IIA NS5-branes this decoupling limit can be defined only when the theory is wrapped on a circle, but nevertheless flows to the ordinary non-compact (0,2) theory at the IR limit. We also see that these theories, in the UV regime, where the non-commutative effects are important, can be described by smeared ordinary D3(D2)-branes in Type IIB(A) string theory.Comment: 13 pages, Latex file, added references and corrected typo

N=(4,4) 2D Supersymmetric Gauge Theory and Brane Configuration

We construct type II A brane configuration of N=(4,4) supersymmetric two dimensional gauge theory with gauge group U(1) and N_f hypermultiplets in the fundamental representation. By lifting to M-theory (strong coupling), we can see the origin of the R-symmetry enhancement of the Coulomb branch. One can also find two theories which become equivalent at strong coupling.Comment: LaTex file, 7 pages, the typos are correcte

Probing Fractionalized Charges

Inspired by holographic entanglement entropy, for geometries with non-zero abelian charges, we define a quantity which is sensitive to the background charges. One observes that there is a critical charge below that the system is mainly described by the metric and the effects of the background charges are just via metric's components. While for charges above the critical one the background gauge field plays an essential role. This, in turn, might be used to define an order parameter to probe phases of a system with fractionalized charges.Comment: Latex file, 17 pages, 7 figures, Published versio

A D2-brane in the Penrose limits of AdS(4)x CP(3)

We consider a D2-brane in the pp-wave backgrounds obtained from AdS$_4\times$CP$^3$ when electric and magnetic fields have been turned on. Upon fixing the light-cone gauge, light-cone Hamiltonian and BPS configurations are obtained. In particular we study BPS configurations with electric dipole on the two sphere giant and a giant graviton rotating in transverse directions. Moreover we show that the gauge field living on the D2-brane is replaced by a scalar field in the light-cone Hamiltonian. We also present a matrix model by regularizing (quantizing) 2-brane theory.Comment: 14 page

On the Supergravity Description of Wilson Loop in Non-commutative Dipole Field Theory

The Wilson loop in the non-commutative dipole field theory is re-examined within the framework of dual gravity description. In contrast to the previous investigations, we let the dual string be moving along the deformed $S^5$ and find the exact expression of the interquark potential. The potential shows a Coulomb behavior at all distance and does not have a minimum distance between quarks, which exhibits in the static configuration. After comparing the potential of the static and moving configurations we find that while the dual string is static at long distance it will transit to a moving configuration at short distance. We also analyze an electric dipole system and find that it shows a similar transition property. Finally, we mention the unsuitable approximation made in the previous paper [hep-th/0701069] and find that the interquark potential in a gauge theory with a non-constant non-commutativity has a Coulomb behavior at all distance.Comment: Pages 12 and 13 are the very short version of ''Erratum to Phys. Lett. B647 (2007) 519''. Pages 1-11 contain detailed calculations and extended discussion