Colloquia

In the first part of the talk I will review the main ideas going from string models to the possibility of low string scales and large extra dimensions. In particular the subjects of bosonic and fermionic strings (IIA, IIB, heterotic and type I/I'), T-duality and D-branes, will be covered. In the second half of the talk I will describe the different scales which can appear in the various string constructions and provide the experimental constraints on transverse (gravitational) and longitudinal (gauge) dimensions using gravitational and collider data.