295 citations · 3k across the 67 of their papers we have counts for
49 papers · 1 filter
Dimensionally Regulated Graviton Self-Energy from Gravitons on de Sitter
B. Yesilyurt, N. C. Tsamis, R. P. Woodard
The graviton self-energy $-i [\mbox{}^{μν} Σ^{ρσ}](x;x')$ is the 1PI 2-point function of quantum gravity. It can be used to quantum-correct the linearized Einstein equation in orde…
Quantum Cosmology in Accelerating Spacetimes II
S. P. Miao, N. C. Tsamis, R. P. Woodard
This paper is a sequel in which we further analyze the recently derived quantum gravity equations which apply in accelerating cosmological spacetimes and whose solutions should be…
Sub-Leading Logarithms for Scalar Potential Models on de Sitter
S. P. Miao, N. C. Tsamis, R. P. Woodard
The continual production of long wavelength scalars and gravitons during inflation injects secular growth into loop corrections which would be constant in flat space. One typically…
Leading Logarithm Quantum Gravity II
S. P. Miao, N. C. Tsamis, R. P. Woodard
This paper is a sequel in which we derive and simplify the gravitational equations that apply in accelerating cosmological spacetimes. Solutions to these equations should be tantam…
Quantum Cosmology in Accelerating Spacetimes
S. P. Miao, N. C. Tsamis, R. P. Woodard
We simplify the gravitational equations which apply in accelerating spacetimes and are consistent with the cosmological principle. Solutions to these equations should be tantamount…
Leading Logarithm Quantum Gravity
S. P. Miao, N. C. Tsamis, R. P. Woodard
The continual production of long wavelength gravitons during primordial inflation endows graviton loop corrections with secular growth factors. During a prolonged period of inflati…
The Third Structure Function
S. P. Miao, N. C. Tsamis, R. P. Woodard +1
We re-consider the graviton self-energy induced by a loop of massless, minimally coupled scalars on de Sitter background. On flat space background it can be represented as a sum of…
Summing Gravitational Effects from Loops of Inflationary Scalars
S. P. Miao, N. C. Tsamis, R. P. Woodard
We develop a procedure for re-summing the large logarithms induced in gravity by loops of inflationary scalars. We first show how the scalar can be integrated out of the field equa…
Alternate Computation of Gravitational Effects from a Single Loop of Inflationary Scalars
S. P. Miao, N. C. Tsamis, R. P. Woodard
We present a new computation of the renormalized graviton self-energy induced by a loop of massless, minimally coupled scalars on de Sitter background. Our result takes account of…
The Need to Renormalize the Cosmological Constant
N. C. Tsamis, R. P. Woodard, B. Yesilyurt
We consider the massless, minimally coupled scalar on de Sitter background. Although the 1-loop divergences of the graviton 1PI 2-point function are canceled by the usual Weyl ($C^…
How Inflationary Gravitons Affect the Force of Gravity
L. Tan, N. C. Tsamis, R. P. Woodard
We employ an unregulated computation the graviton self-energy from gravitons on de Sitter background to infer the renormalized result. This is used to quantum-correct the linearize…
Summing Inflationary Logarithms in Nonlinear Sigma Models
S. P. Miao, N. C. Tsamis, R. P. Woodard
We consider two nonlinear sigma models on de Sitter background which involve the same derivative interactions as quantum gravity but without the gauge issue. The first model contai…
How Inflationary Gravitons Affect Gravitational Radiation
L. Tan, N. C. Tsamis, R. P. Woodard
We include the single graviton loop contribution to the linearized Einstein equation. Explicit results are obtained for one loop corrections to the propagation of gravitational rad…
Graviton Self-Energy from Gravitons in Cosmology
L. Tan, N. C. Tsamis, R. P. Woodard
Although matter contributions to the graviton self-energy $-i[\mbox{}^{μν} Σ^{ρσ}](x;x')$ must be separately conserved on and , graviton contributions obey the weaker…
The Inflaton Effective Potential for General
A. Kyriazis, S. P. Miao, N. C. Tsamis +1
We develop an analytic approximation for the coincidence limit of a massive scalar propagator in an arbitrary spatially flat, homogeneous and isotropic geometry. We employ this to…
From Non-trivial Geometries to Power Spectra and Vice Versa
D. J. Brooker, N. C. Tsamis, R. P. Woodard
We review a recent formalism which derives the functional forms of the primordial -- tensor and scalar -- power spectra of scalar potential inflationary models. The formalism incor…
Final Thoughts on the Power Spectra of Scalar Potential Models
D. J. Brooker, N. C. Tsamis, R. P. Woodard
We give final shape to a recent formalism for deriving the functional forms of the primordial power spectra of single-scalar potential models and theories which are related to them…
Invariant Measure of the One Loop Quantum Gravitational Back-Reaction on Inflation
S. P. Miao, N. C. Tsamis, R. P. Woodard
We use dimensional regularization in pure quantum gravity on de Sitter background to evaluate the one loop expectation value of an invariant operator which gives the local expansio…
Causality Implies Inflationary Back-Reaction
S. Basu, N. C. Tsamis, R. P. Woodard
There is a widespread belief among inflationary cosmologists that a local observer cannot sense super-horizon gravitons. The argument goes that a local observer would subsume super…
An Improved Cosmological Model
N. C. Tsamis, R. P. Woodard
We study a class of non-local, action-based, and purely gravitational models. These models seek to describe a cosmology in which inflation is driven by a large, bare cosmological c…
The Effect of Features on the Functional Form of the Scalar Power Spectrum
D. J. Brooker, N. C. Tsamis, R. P. Woodard
We study how the scalar power spectrum of single-scalar inflation depends functionally on models with features which have been proposed to explain anomalies in the data. We exploit…
Classical Gravitational Back-Reaction
N. C. Tsamis, R. P. Woodard
The quantum gravitational back-reaction on inflation is based on the self-gravitation of infrared gravitons which are ripped out of the vacuum during inflation. The only quantum pa…
Hartree Approximation to the One Loop Quantum Gravitational Correction to the Graviton Mode Function on de Sitter
P. J. Mora, N. C. Tsamis, R. P. Woodard
We use the Hartree approximation to the Einstein equation on de Sitter background to solve for the one loop correction to the graviton mode function. This should give a reasonable…
Pure Gravitational Back-Reaction Observables
N. C. Tsamis, R. P. Woodard
After discussing the various issues regarding and requirements on pure quantum gravitational observables in homogeneous-isotropic conditions, we construct a composite operator obse…