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Publications Influence

On the cosmological constant problem

- I. Antoniadis, N. C. Tsamis
- Physics
- 23 August 1984

Abstract We prove that Weyl invariant theories of gravity possess a remarkable property which, under very general assumptions, explains the stability of flat space-time. We show explicitly how… Expand

555 32- PDF

The Quantum Gravitational Back-Reaction on Inflation

- N. C. Tsamis, R. Woodard
- Physics
- 15 February 1996

Abstract We describe our recent calculation of two-loop corrections to the expansion rate of an initially inflating universe on the manifoldT3× R . If correct, our result proves that quantum… Expand

193 3- PDF

Weyl Invariance and the Cosmological Constant*

A systematic study of a gravitational action possessing local conformal in-variance is undertaken. The spontaneous breaking of the conformal symmetry induces general relativity as an effective long… Expand

2 2- PDF

The graviton propagator in de Donder gauge on de Sitter background

- S. Miao, N. C. Tsamis, R. Woodard
- Physics
- 5 June 2011

We construct the graviton propagator on de Sitter background in exact de Donder gauge. We prove that it must break de Sitter invariance, just like the propagator of the massless, minimally coupled… Expand

45 2- PDF

Relaxing the cosmological constant

- N. C. Tsamis, R. Woodard
- Physics
- 11 March 1993

A non-zero cosmological constant allows massless gravitons to self-interact via a coupling of dimension three. If the cosmological constant is positive then the background geometry will subject… Expand

133 1

The physical basis for infra-red divergences in inflationary quantum gravity

- N. C. Tsamis, R. Woodard
- Physics
- 1 December 1994

We consider tree-order graviton scattering amplitudes on a -dimensional de Sitter background in conformally flat coordinates. Infra-red divergences which cannot be absorbed using conventional… Expand

74 1

de Sitter breaking through infrared divergences

- S. Miao, N. C. Tsamis, R. Woodard
- Physics
- 22 February 2010

Just because the propagator of some field obeys a de Sitter invariant equation does not mean it possesses a de Sitter invariant solution. The classic example is the propagator of a massless,… Expand

58 1- PDF

Perils of analytic continuation

- S. P. Miao, P. J. Mora, N. C. Tsamis, R. Woodard
- Physics
- 23 June 2013

A nice paper by Morrison demonstrates the recent convergence of opinion that has taken place concerning the graviton propagator on de Sitter background. We here discuss the few points which remain… Expand

30 1- PDF

No new physics in conformal scalar-metric theory

- N. C. Tsamis, R. Woodard
- Physics
- 1 May 1986

Abstract Invariantly regulated conformal scalar-metric theories are shown to be physically equivalent to their pure metric analogs. In particular we explicitly disprove the recent claim that these… Expand

17 1

Graviton propagator in a general invariant gauge on de Sitter

- P. J. Mora, N. C. Tsamis, R. Woodard
- Physics
- 20 May 2012

We construct the graviton propagator on de Sitter background in the one parameter family of exact, de Sitter invariant gauges. Our result takes the form of a universal spin two part and a gauge… Expand

37 1- PDF