Speaker
Dr
Yamashita Yasuho
(YITP, Kyoto University)
Description
Recently, a framework of covariant bimetric gravity with no
ghost has been established by assuming a restricted form of
mass interaction between two metrics derived by de Rham,
Gabadadze and Tolley. However, it is not clear why the
interaction term takes this specific form and whether the
theory can be derived from a more natural setup as a low
energy effective theory.
In order to improve our understanding of ghost-free
bigravity, we consider to reproduce this theory from a
braneworld setup as a low energy effective theory. Although
this attempt succeeds in the very limited low energy regime,
there is a problem: doubly coupled matter.
In my talk, I will discuss why doubly coupled matter
anticipates difficulties in our attempt and what is our plan
to work out this problem.
