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Bi-galileon theory II: phenomenology

Padilla, Antonio; Saffin, Paul M.; Zhou, Shuang-Yong


Shuang-Yong Zhou


We continue to introduce bi-galileon theory, the generalisation of the single galileon model introduced by Nicolis et al. The theory contains two coupled scalar fields and is described by a Lagrangian that is invariant under Galilean shifts in those fields. This paper is the second of two, and focuses on the phenomenology of the theory. We are particularly interesting in models that admit solutions that are asymptotically self accelerating or asymptotically self tuning. In contrast to the single galileon theories, we find examples of self accelerating models that are simultaneously free from ghosts, tachyons and tadpoles, able to pass solar system constraints through Vainshtein screening, and do not suffer from problems with superluminality, Cerenkov emission or strong coupling. We also find self tuning models and discuss how Weinberg's no go theorem is evaded by breaking Poincar\'e invariance in the scalar sector. Whereas the galileon description is valid all the way down to solar system scales for the self-accelerating models, unfortunately the same cannot be said for self tuning models owing to the scalars backreacting strongly on to the geometry.


Padilla, A., Saffin, P. M., & Zhou, S. (2011). Bi-galileon theory II: phenomenology. Journal of High Energy Physics, 2011(1),

Journal Article Type Article
Acceptance Date Jan 1, 2011
Publication Date Jan 24, 2011
Deposit Date Apr 21, 2017
Publicly Available Date Apr 21, 2017
Journal Journal of High Energy Physics
Electronic ISSN 1029-8479
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 2011
Issue 1
Public URL
Publisher URL


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