334 citations · 4k across the 75 of their papers we have counts for
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Caustics for Spherical Waves
Claudia de Rham, Hayato Motohashi
We study the development of caustics in shift-symmetric scalar field theories by focusing on simple waves with an -symmetry in an arbitrary number of space dimensions. We sh…
Fundamental theorem on gauge fixing at the action level
Hayato Motohashi, Teruaki Suyama, Kazufumi Takahashi
Regardless of the long history of gauge theories, it is not well recognized under which condition gauge fixing at the action level is legitimate. We address this issue from the Lag…
Self-accelerating Massive Gravity: Hidden Constraints and Characteristics
Pavel Motloch, Wayne Hu, Hayato Motohashi
Self-accelerating backgrounds in massive gravity provide an arena to explore the Cauchy problem for derivatively coupled fields that obey complex constraints which reduce the phase…
Healthy degenerate theories with higher derivatives
Hayato Motohashi, Karim Noui, Teruaki Suyama +2
In the context of classical mechanics, we study the conditions under which higher-order derivative theories can evade the so-called Ostrogradsky instability. More precisely, we con…