Mar 2 – 20, 2015
Nordita, Stockholm
Europe/Stockholm timezone

The square-root matrix in ghost-free bimetric theory

Mar 9, 2015, 4:00 PM
FB53 (Nordita, Stockholm)


Nordita, Stockholm


Dr Angnis SCHMIDT-MAY (ETH Zürich)


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.

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