Speaker
Dr
Angnis SCHMIDT-MAY
(ETH Zürich)
Description
The recent development of ghost-free nonlinear massive
gravity and its generalization to bimetric theory has
created an exciting new research area within theoretical
cosmology. Bimetric theory can be viewed as a deformation of
general relativity by the presence of a massive spin-2
field. It is usually formulated in terms of two metrics with
individual Einstein-Hilbert terms as well as an interaction
potential whose structure is severely constrained by
consistency. In particular, the interactions contain a
matrix square-root which may not always be well-defined and
unfortunately complicates many computations. In this talk, I
will provide the conditions under which the square-root
matrix is well-defined and discuss their relation to the
vierbein formulation of bimetric theory. Moreover, I will
suggest a method of dealing with the linear variation of the
square root which can simplify the treatment of perturbation
theory around curved backgrounds.
