A Comment on Zero-brane Quantum Mechanics

We consider low energy, non-relativistic scattering of two Dirichlet zero-branes as an exercise in quantum mechanics. For weak string coupling and sufficiently small velocity, the dynamics is governed by an effective U(2) gauge theory in 0+1 dimensions. At low energies, D-brane scattering can reliably probe distances much shorter than the string scale. The only length scale in the quantum mechanics problem is the eleven dimensional Planck length. This provides evidence for the role of scales shorter than the string length in the weakly coupled dynamics of type IIA strings.Comment: 9 pages, harvmac, improved treatment of 2+1 proble

D-branes and Matrix Theory in Curved Space

We discuss the relation between supersymmetric gauge theory of branes and supergravity; as it was discovered in D-brane physics, and as it appears in Matrix theory, with emphasis on motion in curved backgrounds. We argue that gauged sigma model Lagrangians can be used as definitions of Matrix theory in curved space. Lecture given at Strings '97; June 20, 1997.Comment: LaTeX with espcrc2; 13 pages, STRINGS97. References added; a speculation refute

Superstring Scattering from D-Branes

We derive fully covariant expressions for all two-point scattering amplitudes of two massless closed strings from a Dirichlet $p$-brane. This construction relies on the observation that there is a simple relation between these D-brane amplitudes in type II superstring theory and four-point scattering amplitudes for type I open superstrings. From the two-point amplitudes, we derive the long range background fields for the D-branes, and verify that as expected they correspond to those of extremally charged $p$-brane solutions of the low energy effective action.Comment: 33 pages, Latex, 4 figure

Self-Dual Supersymmetric Dirac-Born-Infeld Action

We present a self-dual N=1 supersymmetric Dirac-Born-Infeld action in three dimensions. This action is based on the supersymmetric generalized self-duality in odd dimensions developed originally by Townsend, Pilch and van Nieuwenhuizen. Even though such a self-duality had been supposed to be very difficult to generalize to a supersymmetrically interacting system, we show that Dirac-Born-Infeld action is actually compatible with supersymmetry and self-duality in three-dimensions. The interactions can be further generalized to arbitrary (non)polynomial interactions. As a by-product, we also show that a third-rank field strength leads to a more natural formulation of self-duality in 3D. We also show an interesting role played by the third-rank field strength leading to a supersymmetry breaking, in addition to accommodating a Chern-Simons form.Comment: 12 pages, no figure

A Note on Marginally Stable Bound States in Type II String Theory

Spectrum of elementary string states in type II string theory contains ultra-short multiplets that are marginally stable. $U$-duality transformation converts these states into bound states at threshold of $p$-branes carrying Ramond-Ramond charges, and wrapped around $p$-cycles of a torus. We propose a test for the existence of these marginally stable bound states. Using the recent results of Polchinski and of Witten, we argue that the spectrum of bound states of $p$-branes is in agreement with the prediction of $U$-duality.Comment: LaTeX file, 6 page

De Sitter Holography and the Cosmic Microwave Background

We interpret cosmological evolution holographically as a renormalisation group flow in a dual Euclidean field theory, as suggested by the conjectured dS/CFT correspondence. Inflation is described by perturbing around the infra-red fixed point of the dual field theory. The spectrum of the cosmic microwave background radiation is determined in terms of scaling violations in the field theory. The dark energy allows similar, albeit less predictive, considerations. We discuss the cosmological fine-tuning problems from the holographic perspective.Comment: 17 pages, 2 figures, uses JHEP style files; corrected and added reference

Covariant Action for the Super-Five-Brane of M-Theory

We propose a complete, d=6 covariant and kappa-symmetric, action for an M-theory five-brane propagating in D=11 supergravity background.Comment: LaTeX file, 5 pages, misprints corrected, comments and references adde

On the Baryonic Branch Root of N=2 MQCD

We investigate the brane exchange in the framework of N=2 MQCD by using a specific family of M fivebrane configurations relevant to describe the baryonic branch root. An exchange of M fivebranes is realized in the Taub-NUT geometry and controlled by the moduli parameter of the configurations. This family also provides two different descriptions of the root. These descriptions are examined carefully using the Taub-NUT geometry. It is shown that they have the same baryonic branch and are shifted each other by the brane exchange.Comment: LaTeX, 25 pages, 7 figures, references adde

Coupling of branes and normalization of effective actions in string/M-theory

We discuss issues involving p(D)- brane charge quantization and the normalization of effective actions, in string/M-theory. We also construct the action of (the bosonic sector of) eleven dimensional supergravity in the presence of two- and five- branes and discuss (perturbative) anomaly cancellation.Comment: Discussion of anomaly cancellation expanded. 36 pages, latex, no figure

Exile Vol. XXXI No. 1

Drawing by Chris Bradley 1 How Goes the Wombat, Prithee by Jennie Benford 3 Holy Shit (for Mary) by Stephanie Athey 4-5 ..... blues by Britton R. Creelman 6 Photograph (anonymous) 7 Prose by Leigh Walton 9-12 San Jacinto by Petersen S. Thomas 13 Rebuttal by Betsy Oster 15 Running Alone by Ann Townsend McMullen 16 Windows in Florence by Michael Parr 17 Rangers by Caroline Palmer 19 Salamapo by Mary Deborah Clark 20-21 Funeral by J. K. Rand 22 Deeds Give No Title by Douglas Jones 23 Be Careful, There\u27s a Straight Bar Next Door by Karen J. Hall 25 The Rivers of Saigon by Alex Dickson 26 2 Sketches by Alfred Sturla Bodvarsson 27 Upon the Occasion of Reading 236 sonnets at One Sitting by Jeff Masten 28 I just believe in Me by Rob Jackson 29 Close by Stephanie Athey 31 Teller by Katherine Fox Reynolds 32 Woman in Greece by Michael Parr 33 Part of the Job by Joan DeWitt 35-44 Contributor Notes 46 Editorial decision is shared equally among the seven member editorial board. -title page Polymorphous: Cover Lithograph by Aimee Creelman - title pag