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Alexey Golovnev (Saint Petersburg State University)
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New ideas in massive gravity
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Massive gravity dates back to the classical paper of Fierz
and Pauli in which it has been shown how to get rid off the
sixth (ghost) polarisation of the massive graviton, at the
linear level. However, for quite a long time it was widely
believed that the Boulware-Deser ghost inevitably comes back
with non-linear corrections. This obstacle was surmounted in
2010 at the price of introducing a square root of a matrix
into the action which naturally entails certain existence and uniqueness issues. I will review modern theories of massive gravity and their problems,
and also will give a new formulation of the model, directly in terms of elementary symmetric polynomials of eigenvalues instead of the matrices themselves.
It turns out that the new construction has a wider range of
applicability.