Journal
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
Volume -, Issue 3, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/1475-7516/2019/03/006
Keywords
gravity; modified gravity
Funding
- Chinese National Youth Thousand Talents Program [71000-41180003]
- SYSU start-up funding [71000-52601106]
- JSPS KAKENHI [JP25287054, JP15H05888, JP18H04579, JP18K18764]
- Mitsubishi Foundation
- JSPS Postdoctoral Fellowships for Research Abroad
Ask authors/readers for more resources
We propose a new class of higher derivative scalar-tensor theories without the Ostrogradsky's ghost instabilities. The construction of our theory is originally motivated by a scalar field with spacelike gradient, which enables us to fix a gauge in which the scalar field appears to be non-dynamical. We dub such a gauge as the spatial gauge. Though the scalar field loses its dynamics, the spatial gauge fixing breaks the time diffeomorphism invariance and thus excites a scalar mode in the gravity sector. We generalize this idea and construct a general class of scalar-tensor theories through a non-dynamical scalar field, which preserves only spatial covariance. We perform a Hamiltonian analysis and confirm that there are at most three (two tensors and one scalar) dynamical degrees of freedom, which ensures the absence of a degree of freedom due to higher derivatives. Our construction opens a new branch of scalar-tensor theories with higher derivatives.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available