D-branes and short distances in string theory

• Published in: Nuclear physics. B 1997-02, Vol.485 (1), p.85-127
• Main Authors: Douglas, Michael R., Kabat, Daniel, Pouliot, Philippe, Shenker, Stephen H.
• Format: Article
• Language: English
• Subjects: Bound state at threshold; D-brane; M-theory; Non-commutati; Nonperturbative string theory; Short-distance structure; Spacetime geometry; Topology change
• ISSN: 0550-3213; 1873-1562
• DOI: 10.1016/S0550-3213(96)00619-0

We study the behavior of D-branes at distances far shorter than the string length scale l s . We argue that short-distance phenomena are described by the IR behavior of the D-brane worldvolume quantum theory. This description is valid until the brane motion becomes relativistic. At weak string coupling g s this corresponds to momenta and energies far above string scale. We use 0-brane quantum mechanics to study 0-brane collisions and find structure at length scales corresponding to the eleven-dimensional Planck length ( l p 11 ∼ g s 1 3 l ss ) and to the radius of the eleventh dimension in M-theory ( R 11, ∼ g s l s ). We use 0-branes to probe non-trivial geometries and topologies at sub-stringy scales. We study the 0-brane 4-brane system, calculating the 0-brane moduli space metric, and find the bound state at threshold, which has characteristic size l p 11. We examine the blowup of an orbifold and are able to resolve the resulting S 2 down to size l p 11. A 0-brane with momentum approaching 1/ R 11 is able to explore a larger configuration space in which the blowup is embedded. Analogous phenomena occur for small instantons. We finally turn to 1-branes and calculate the size of a bound state to be ∼ g s 1 2 l s , the l-brane tension scale.