DE1 - Dark Energy and the Accelerating Universe |
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Speaker |
Motohashi, Hayato |
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Coauthors |
Motohashi, Hayato; Noui, Karim; Suyama, Teruaki; Yamaguchi, Masahide; Langlois, David |
| Talk Title |
Constructing ghost-free theories with higher derivatives |
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Abstract |
Scalar-tensor theories serve models for inflation and dark energy. Many efforts have been made recently for constructing the most general scalar-tensor theories with higher-order derivatives in their Lagrangian. Since higher-derivative theories are typically associated with Ostrogradsky ghost which causes unbounded Hamiltonian, it is important to clarify how to evade it. In this talk, I will explain construction of healthy degenerate theories with higher-order derivatives which circumvent Ostrogradsky ghost. ----- References: Motohashi, Suyama, Phys. Rev. D91 (2015) 8, 085009, [arXiv:1411.3721]. Motohashi, Noui, Suyama, Yamaguchi, Langlois, JCAP 1607 (2016) 07, 033, [arXiv:1603.09355]. Motohashi, Suyama, Yamaguchi, arXiv:1711.08125. |
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