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Publications Influence

Avoiding dark energy with 1/r modifications of gravity

- R. Woodard
- Physics
- 30 January 2006

Scalar quintessence seems epicyclic because one can choose the potential to reproduce any cosmology (I review the construction) and because the properties of this scalar seem to raise more questions… Expand

442 14- PDF

Nonlocal cosmology.

- S. Deser, R. Woodard
- Physics, Medicine
- Physical review letters
- 14 June 2007

We explore nonlocally modified models of gravity, inspired by quantum loop corrections, as a mechanism for explaining current cosmic acceleration. These theories enjoy two major advantages: they… Expand

238 13- PDF

The Problem of Nonlocality in String Theory

- D. Eliezer, R. Woodard
- Physics
- 16 October 1989

Abstract We discuss the problems associated with the essential nonlocality of all string field actions. Manifestly Poincare invariant theories are shown to be unstable and bereft of an initial value… Expand

220 10

Observational viability and stability of nonlocal cosmology

- S. Deser, R. Woodard
- Physics
- 25 July 2013

We show that the nonlocal gravity models, proposed to explain current cosmic acceleration without dark energy, pass two essential tests: first, they can be defined so as not to alter the,… Expand

100 9- PDF

Ostrogradsky's theorem on Hamiltonian instability

- R. Woodard
- Mathematics, Computer Science
- Scholarpedia
- 6 June 2015

TLDR

251 8

The Theorem of Ostrogradsky

- R. Woodard
- Physics
- 7 June 2015

Ostrogradsky’s construction of a Hamiltonian formalism for nondegenerate higher derivative Lagrangians is reviewed. The resulting instability imposes by far the most powerful restriction on… Expand

105 7- PDF

Nonlocal Models of Cosmic Acceleration

- R. Woodard
- Physics
- 1 January 2014

I review a class of nonlocally modified gravity models which were proposed to explain the current phase of cosmic acceleration without dark energy. Among the topics considered are deriving causal and… Expand

95 5- PDF

Maximally symmetric vector propagator

- N. Tsamis, R. Woodard
- Physics
- 14 August 2006

We derive the propagator for a massive vector field on a de Sitter background of arbitrary dimension. This propagator is de Sitter invariant and possesses the proper flat space-time and massless… Expand

53 5- PDF

Reconstructing the Distortion Function for Nonlocal Cosmology

- C. Deffayet, R. Woodard
- Physics
- 6 April 2009

We consider the cosmology of modified gravity models in which Newton's constant is distorted by a function of the inverse d'Alembertian acting on the Ricci scalar. We derive a technique for choosing… Expand

100 4- PDF

Leading log solution for inflationary Yukawa theory

- S. Miao, R. Woodard
- Physics
- 27 February 2006

We generalize Starobinskii's stochastic technique to the theory of a massless, minimally coupled scalar interacting with a massless fermion in a locally de Sitter geometry. The scalar is an 'active'… Expand

106 4- PDF