Speaker
Prof.
Michael Volkov
(University of Tours)
Description
I calculate the energy in the dRGT massive gravity.
This requires resolving the constraints, which can be
done in the spherically symmetric sector. The energy
is found to be positive for globally regular and
asymptotically flat fields constituting the
"physical sector" of the theory. There are also
solutions of the constraints whose energy is
negative and unbounded from below and which show
tachyons. However, these solutions are either not
globally regular or not asymptotically flat. They
cannot describe initial data triggering ghost instability
of the physical sector. This allows one to conjecture
that the physical sector is protected from the instability
by a potential barrier separating it from superluminal
and negative energy states.
I also consider cosmological applications.
