artículo con referato
"Global Phase Time and Path Integral for String Cosmological Models"
C. Simeone and G. Giribet
Mod. Phys. Lett. A 16(1) (2001) 19-27
Abstract
A global phase time is identified for homogeneous and isotropic cosmological models yielding from the low energy effective action of closed bosonic string theory. When the Hamiltonian constraint allows for the existence of an 0intrinsic time, the quantum transition amplitude is obtained by means of the usual path integral procedure for gauge systems.
DIVISION FISICA TEORICA