Metastring theory and modular spacetime
Abstract
String theory is canonically accompanied with a spacetime interpretation which determines Smatrixlike observables, and connects to the standard physics at low energies in the guise of local effective field theory. Recently, we have introduced a reformulation of string theory which does not rely on an a priori spacetime interpretation or a preassumption of locality. This metastring theory is formulated in such a way that stringy symmetries (such as Tduality) are realized linearly. In this paper, we study metastring theory on a flat background and develop a variety of technical and interpretational ideas. These include a formulation of the moduli space of Lorentzian worldsheets, a careful study of the symplectic structure and consequently consistent closed and open boundary conditions, and the string spectrum and operator algebra. What emerges from these studies is a new quantum notion of spacetime that we refer to as a quantum Lagrangian or equivalently a modular spacetime. This concept embodies the standard tenets of quantum theory and implements in a precise way a notion of relative locality. The usual string backgrounds (noncompact spacetime along with some toroidally compactified spatial directions) are obtained from modular spacetime by a limiting procedure that can be thought of as a correspondence limit.
 Publication:

Journal of High Energy Physics
 Pub Date:
 June 2015
 DOI:
 10.1007/JHEP06(2015)006
 arXiv:
 arXiv:1502.08005
 Bibcode:
 2015JHEP...06..006F
 Keywords:

 Bosonic Strings;
 Conformal Field Models in String Theory;
 String Duality;
 High Energy Physics  Theory