Fortschritte der physik-progress of physics vol:50 issue:8-9 pages:923-929
RTN Workshop On The Quantum Structure Of Spacetime And The Geometric Nature Of Fundamental Interactions date:13-20 September 2001
We review a method to find the non-abelian open superstring effective action, thereby settling the issue of the ordering ambiguities. We start from solutions to Yang-Mills which, in D-brane context, define certain BPS configurations. Studying their deformations in the abelian case shows that the Born-Infeld action is the unique deformation which admits solutions of this type. By applying the method to the non-abelian case we calculated the full effective action through O(alpha'^3). The presence of derivative terms turns out to be essential. Testing the result by comparing the spectrum in the presence of a constant magnetic background field with the string theory prediction, we obtain perfect agreement.