Speaker
Stefano Giaccari
(Università di Padova)
Description
Orbifolding in string theory is a standard procedure to get new theories from old ones either by gauging a global symmetry of the worldsheet sigma model or by quotienting a geometric string background by some isometries. The absence of global symmetries characterizes all known string theory models (and, conjecturally, all theories of quantum gravity), so that the orbifold procedure from a purely spacetime quantum field theoretic perspective is not fully understood. We illustrate a proposal for an orbifold procedure that does not rely on worldsheet techniques. We discuss some simple examples and possible consequences.
