Null Branes in String Theory Backgrounds

We consider null bosonic p-branes moving in curved space-times and develop a method for solving their equations of motion and constraints, which is suitable for string theory backgrounds. As an application, we give an exact solution for such background in ten dimensions.Comment: 11 pages, LaTeX. Final version, to appear in Phys. Rev.

M2-brane Solutions in AdS_7xS^4

We consider different M2-brane configurations in the M-theory AdS_7xS^4 background, with field theory dual A_{N-1}(2,0) SCFT. New membrane solutions are found and compared with the recently obtained ones.Comment: LaTeX, 18 pages, no figures; V2: cosmetic changes to match the version published in JHE

M2-brane Perspective on N=6 Super Chern-Simons Theory at Level k

Recently, O. Aharony, O. Bergman, D. L. Jafferis and J. Maldacena (ABJM) proposed three-dimensional super Chern-Simons-matter theory, which at level k is supposed to describe the low energy limit of N M2-branes. For large N and k, but fixed 't Hooft coupling \lambda=N/k, it is dual to type IIA string theory on AdS_4 x CP^3. For large N but finite k, it is dual to M theory on AdS_4 x S^7/Z_k. In this paper, relying on the second duality, we find exact giant magnon and single spike solutions of membrane configurations on AdS_4 x S^7/Z_k by reducing the system to the Neumann-Rosochatius integrable model. We derive the dispersion relations and their finite-size corrections with explicit dependence on the level k.Comment: 19 pages, References adde

Tensionless branes and the null string critical dimension

BRST quantization is carried out for a model of p-branes with second class constraints. After extension of the phase space the constraint algebra coincides with the one of null string when p=1. It is shown that in this case one can or can not obtain critical dimension for the null string, depending on the choice of the operator ordering and corresponding vacuum states. When p>1, operator orderings leading to critical dimension in the p=1 case are not allowed. Admissable orderings give no restrictions on the dimension of the embedding space-time. Finally, a generalization to supersymmetric null branes is proposed.Comment: 12 pages, LaTeX 2.09. Title changed. Change in the transition from second class constraints to first class ones. Comments, conclusions, references, acknowledgments and report-no adde