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arXiv · 0908.1954

Unitarity of spin-2 theories with linearized Weyl symmetry in $D=2+1$

D. Dalmazi
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Abstract

Here we prove unitarity of the recently found fourth-order self-dual model of spin-2 by investigating the analytic structure of its propagator. The model describes massive particles of helicity +2 (or -2) in $D=2+1$ and corresponds to the quadratic truncation of a higher derivative topologically massive gravity about a flat background. It is an intriguing example of a theory where a term in the propagator of the form $1/\lbrack\Box^2 (\Box - m^2)\rbrack $ does not lead to ghosts. The crucial role of the linearized Weyl symmetry in getting rid of the ghosts is pointed out. We use a peculiar pair of gauge conditions which fix the linearized reparametrizations and linearized Weyl symmetries separetely.

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D. Dalmazi. 2009-08-13. Unitarity of spin-2 theories with linearized Weyl symmetry in $D=2+1$. https://doi.org/10.1103/physrevd.80.085008

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