spacetime states in Rovelli's book "Quantum Gravity" happy new year everybody, I am reading "quantum gravity" of Rovelli. He introduces functions f(x,t) defined on compact of space time that are zero outside. They correspond to the time and space needed to a measurement. page 168: they generalize conventional wave packets for which [tex]f(x,t) = f(x) \delta(t) [/tex] which are associated to instantaneous measurements. There is no equation for them He constructs the usual wave fonction [tex]\phi(x',t') = \int dx dt w(x',t',x,t) f(x,t)[/tex] Where w is the propagator. This wave function satisfies the Schrodinger equation. We lose the information we had with f! He says f and f' are equivalent iff they give the same [tex]\phi[/tex] Ok but why have we not to use the information in f?