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arXiv · 1701.02926

Generalized multi-Galileons, covariantized new terms, and the no-go theorem for non-singular cosmologies

Shingo Akama·Tsutomu Kobayashi
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Abstract

It has been pointed out that non-singular cosmological solutions in second-order scalar-tensor theories generically suffer from gradient instabilities. We extend this no-go result to second-order gravitational theories with an arbitrary number of interacting scalar fields. Our proof follows directly from the action of generalized multi-Galileons, and thus is different from and complementary to that based on the effective field theory approach. Several new terms for generalized multi-Galileons on a flat background were proposed recently. We find a covariant completion of them and confirm that they do not participate in the no-go argument.

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Shingo Akama, Tsutomu Kobayashi. 2017-04-10. Generalized multi-Galileons, covariantized new terms, and the no-go theorem for non-singular cosmologies. https://doi.org/10.1103/physrevd.95.064011

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