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Is Cosmic Speed-Up Due to New Gravitational Physics?
We show that cosmic acceleration can arise due to very tiny corrections to the usual gravitational action of general relativity, of the form ${R}^{\ensuremath{-}n}$ with $ng0.$ This model eliminates
Beyond the Cosmological Standard Model
After a decade and a half of research motivated by the accelerating universe, theory and experiment have a reached a certain level of maturity. The development of theoretical models beyond \Lambda,
Cosmology of generalized modified gravity models
We consider general curvature-invariant modifications of the Einstein-Hilbert action that become important only in regions of extremely low space-time curvature. We investigate the far future
Electroweak Baryogenesis
We demonstrate the viability of electroweak baryogenesis scenarios in which the necessary departure from equilibrium is realized by the evolution of a network of topological defects. We consider
Galileons as Wess-Zumino terms
A bstractWe show that the galileons can be thought of as Wess-Zumino terms for the spontaneous breaking of space-time symmetries. Wess-Zumino terms are terms which are not captured by the coset
Symmetries for Galileons and DBI scalars on curved space
We introduce a general class of four-dimensional effective field theories which include curved space Galileons and DBI theories possessing nonlinear shift-like symmetries. These effective theories
Multifield Galileons and higher codimension branes
In the decoupling limit, the Dvali-Gabadadze-Porrati model reduces to the theory of a scalar field $\ensuremath{\pi}$, with interactions including a specific cubic self-interaction---the Galileon
Constraining Interactions in Cosmology's Dark Sector
We consider the cosmological constraints on theories in which there exists a nontrivial coupling between the dark matter sector and the sector responsible for the acceleration of the universe, in
Can the dark energy equation - of - state parameter w be less than -1?
Models of dark energy are conveniently characterized by the equation-of-state parameter $w=p/\ensuremath{\rho},$ where $\ensuremath{\rho}$ is the energy density and p is the pressure. Imposing the
The classical double copy in maximally symmetric spacetimes
A bstractThe classical double copy procedure relates classical asymptotically-flat gravitational field solutions to Yang-Mills and scalar field solutions living in Minkowski space. In this paper we