Seminario
"From clock synchronization to dark matter as a relativistic inertial effect."
Relatore: Luca Lusanna INFN  Firenze
Aula Feynman
22 Marzo 2011 ore 16.00
Abstract

Clock synchronization leads to the definition of instantaneous 3spaces (to be used as Cauchy surfaces)
in noninertial frames, the only ones allowed by the equivalence principle. ADM canonical tetrad gravity in asymptotically Minkowskian spacetimes can be described in this framework. This allows to find the York canonical basis in which the inertial (gauge) and tidal (physical) degrees of freedom of the gravitatinal field can be identified. A PostMinkowskian linearization with respect to the asymptotic Minkowski metric (aymptotic
background) allows to solve the Dirac constraints in nonharmonic 3orthogonal gauges and to find nonharmonic
TT gravitational waves. The inertial gauge variable
York time (the trace of the extrinsic curvature of the 3space) describes the general relativistic freedom in clock
synchronization. After a digression on the gauge problem in general relativity, it is shown that dark matter, whose experimental signatures are the rotation curves and the mass of galaxies, may be described (at least partially) as an inertial relativistic effect (absent in Newton gravity) connected with the York time.


