Showing 1 - 10 of 34 Items

Date: 2003-02-03

Creator: Stephen G. Naculich, Howard J. Schnitzer, Niclas Wyllard

Access: Open access

We study the pp-wave limits of various elliptic models with orientifold planes and D7-branes, as well as the pp-wave limit of an orientifold of AdS5 × T11. Many of the limits contain both open and closed strings. We also present pp-wave limits of theories which give rise to a compact null direction and contain open strings. Maps between the string theory states and gauge theory operators are proposed. © 2002 Elsevier Science B.V. All rights reserved.

Date: 1998-12-21

Creator: Isabel P. Ennes, Stephen G. Naculich, Henric Rhedin, Howard J. Schnitzer

Access: Open access

One-instanton predictions are obtained from certain non-hyperelliptic Seiberg-Witten curves derived from M-theory for N = 2 supersymmetric gauge theories. We consider SU(N1) × SU(N2) gauge theory with a hypermultiplet in the bifundamental representation together with hypermultiplets in the defining representations of SU(N1) and SU(N2). We also consider SU(N) gauge theory with a hypermultiplet in the symmetric or antisymmetric representation, together with hypermultiplets in the defining representation. The systematic perturbation expansion about a hyperelliptic curve together with the judicious use of an involution map for the curve of the product groups provide the principal tools of the calculations. © 1999 Elsevier Science B.V.

Date: 2009-11-11

Creator: Stephen G. Naculich, Howard J. Schnitzer

Access: Open access

We derive a compact all-loop-order expression for the IR-divergent part of the = 4 SYM four-gluon amplitude, which includes both planar and all subleading-color contributions, based on the assumption that the higher-loop soft anomalous dimension matrices are proportional to the one-loop soft anomalous dimension matrix, as has been recently conjectured. We also consider the Regge limit of the four-gluon amplitude, and we present evidence that the leading logarithmic growth of the subleading-color amplitudes is less severe than that of the planar amplitudes. We examine possible 1/N 2 corrections to the gluon Regge trajectory, previously obtained in the planar limit from the BDS ansatz. The double-trace amplitudes have Regge behavior as well, with a nonsense-choosing Regge trajectory and a Regge cut which first emerges at three loops. © SISSA 2009.

Date: 2008-05-01

Creator: Stephen G. Naculich, Howard J. Schnitzer

Access: Open access

It is shown that the four-gluon scattering amplitude for N = 4 supersymmetric Yang-Mills theory in the planar limit can be written, in both the weak- and strong-coupling limits, as a reggeized amplitude, with a parent trajectory and an infinite number of daughter trajectories. This result is not evident a priori, and relies crucially on the fact that the leading IR-divergence and the finite log2 (s / t)-dependent piece of the amplitude are characterized by the same function for all values of the coupling, as conjectured by Bern, Dixon, and Smirnov, and proved by Alday and Maldacena in the strong-coupling limit. We use the Alday-Maldacena result to determine the exact strong-coupling Regge trajectory. © 2007 Elsevier B.V. All rights reserved.

Date: 2005-05-02

Creator: Marta Gómez-Reino, Stephen G. Naculich, Howard J. Schnitzer

Access: Open access

An exact fully-localized extremal supergravity solution for N2 D2-branes and N6 D6-branes, which is dual to 3-dimensional supersymmetric SU(N2) gauge theory with N6 fundamentals, was found by Cherkis and Hashimoto. In order to consider the thermal properties of the gauge theory we present the non-extremal extension of this solution to first order in an expansion near the core of the D6-branes. We compute the Hawking temperature and the black-brane horizon area/entropy. The leading-order entropy, which is proportional to N23/2N61/2 TH2, is not corrected to first order in the expansion. This result is consistent with the analogous weak-coupling result at the correspondence point N2 ∼ N6. © 2005 Elsevier B.V. All rights reserved.

Date: 2003-02-24

Creator: Stephen G. Naculich, Howard J. Schnitzer, Niclas Wyllard

Access: Open access

We perform a completely perturbative matrix model calculation of the physical low-energy quantities of the N = 2 U(N) gauge theory. Within the matrix model framework we propose a perturbative definition of the periods a i in terms of certain tadpole diagrams, and check our conjecture up to first order in the gauge theory instanton expansion. The prescription does not require knowledge of the Seiberg-0Witten differential or curve.We also compute the N = 2 prepotential F(a) perturbatively up to the first-instanton level, finding agreement with the known result. 2002 Elsevier Science B.V. All rights reserved.

Date: 2001-08-27

Creator: Stephen G. Naculich, Howard J. Schnitzer, Niclas Wyllard

Access: Open access

We find the classical supersymmetric vacuum states of a class of N =1* field theories obtained by mass deforming superconformal models with simple gauge groups and N =4 or N =2 supersymmetry. In particular, new classical vacuum states for mass-deformed N =4 models with Sp(2N) and SO(N) gauge symmetry are found. We also derive the classical vacua for various mass-deformed N =2 models with Sp(2N) and SU(N) gauge groups and antisymmetric (and symmetric) hypermultiplets. We suggest interpretations of the mass-deformed vacua in terms of three-branes expanded into five-brane configurations. © 2001 Elsevier Science B.V.

Date: 2004-04-01

Creator: Marta Gómez-Reino, Howard J. Schnitzer, Stephen G. Naculich

Access: Open access

We present a matrix-model expression for the sum of instanton contributions to the prepotential of an N = 2 supersymmetric U (N) gauge theory, with matter in various representations. This expression is derived by combining the renormalization-group approach to the gauge theory prepotential with matrix-model methods. This result can be evaluated order-by-order in matrix-model perturbation theory to obtain the instanton corrections to the prepotential. We also show, using this expression, that the one-instanton prepotential assumes a universal form. © SISSA/ISAS 2004.

Date: 2013-04-19

Creator: Stephen G. Naculich, Horatiu Nastase, Howard J. Schnitzer

Access: Open access

The infrared singularities of gravitational amplitudes are one-loop exact, in that higher-loop divergences are characterized by the exponential of the one-loop divergence. We show that the contributions to SU(N) gauge-theory amplitudes that are mostsubleading in the 1/N expansion are also one-loop exact, provided that the dipole conjecture holds. Possible corrections to the dipole conjecture, beginning at three loops, could violate one-loop-exactness, though would still maintain the absence of collinear divergences. We also demonstrate a relation between L-loop four-point N = 8 supergravity and mostsubleading-color N = 4 SYM amplitudes that holds for the two leading IR divergences, (Formula presented.) and (Formula presented.), but breaks down at (Formula presented.).

Date: 2006-04-17

Creator: Stephen G. Naculich, Howard J. Schnitzer

Access: Open access

The consequences of level-rank duality for untwisted D-branes on an SU(N) group manifold are explored. Relations are found between the charges of D-branes (which are classified by twisted K-theory) belonging to su (N)K and su (K)N theories, in the case of odd N + K. An isomorphism between the charge algebras is also demonstrated in this case. © 2006 Elsevier B.V. All rights reserved.