A universality in ppwaves
Abstract
We discuss a universality property of any covariant field theory in spacetime expanded around ppwave backgrounds. According to this property the spacetime lagrangian density evaluated on a restricted set of field configurations, called universal sector, turns out to be same around all the ppwaves, even offshell, with same transverse space and same profiles for the background scalars. In this paper we restrict our discussion to tensorial fields only. In the context of bosonic string theory we consider onshell ppwaves and argue that universality requires the existence of a universal sector of worldsheet operators whose correlation functions are insensitive to the ppwave nature of the metric and the background gauge flux. Such results can also be reproduced using the worldsheet conformal field theory. We also study such ppwaves in nonpolynomial closed string field theory (CSFT). In particular, we argue that for an offshell ppwave ansatz with flat transverse space and dilaton independent of transverse coordinates the field redefinition relating the low energy effective field theory and CSFT with all the massive modes integrated out is at most quadratic in fields. Because of this simplification it is expected that the offshell ppwaves can be identified on the two sides. Furthermore, given the massless ppwave field configurations, an iterative method for computing the higher massive modes using the CSFT equations of motion has been discussed. All our bosonic string theory analyses can be generalised to the common NeveuSchwarz sector of superstrings.
 Publication:

Journal of High Energy Physics
 Pub Date:
 June 2007
 DOI:
 10.1088/11266708/2007/06/061
 arXiv:
 arXiv:0704.0085
 Bibcode:
 2007JHEP...06..061M
 Keywords:

 High Energy Physics  Theory
 EPrint:
 LaTeX file, 43 pages, one reference added, minor changes made