Some Adventures in the Search for a Modified Gravity Explanation for Cosmic Acceleration

Mark Trodden

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Some Adventures in the Search for a Modified Gravity Explanation for Cosmic Acceleration

Mark Trodden

General Relativity and Quantum Cosmology · Submitted 4 May 2011

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim The discovery of cosmic acceleration has raised the intriguing possibility that we are witnessing the first breakdown of General Relativity on cosmological scales.

how it is stated · hedged possibility 0.95 read the record →

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The compiled record

The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

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Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 4,257 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.33 · human participants 0.02 · controlled comparison 0.02 · randomized assignment 0.01 · states quantitative result 0.03 · compares with prior results 0.06 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; show every role.

The discovery of cosmic acceleration has raised the intriguing possibility that we are witnessing the first breakdown of General Relativity on cosmological scales. In this article I will briefly review current attempts to construct a theoretically consistent and observationally viable modification of gravity that is capable of describing the accelerating universe. I will discuss f(R) models, and their obvious extensions, and the DGP model as an example of extra-dimensional implementations. I will then briefly describe the Galileon models and their very recent multifield and curved space extensions - a class of four-dimensional effective field theories encoding extra dimensional modifications to gravity. This article is dedicated to the career of my friend and former colleague, Joshua Goldberg, and is written to appear in his festschrift.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	The discovery of cosmic acceleration has raised the intriguing possibility that we are witnessing the first breakdown of General Relativity on cosmological scales.	background 1.00	0.03	0.06	hedged possibility 0.95
s1	In this article I will briefly review current attempts to construct a theoretically consistent and observationally viable modification of gravity that is capable of describing the accelerating universe.	contribution 0.92	0.13	0.05	unclear 0.52
s2	I will discuss f(R) models, and their obvious extensions, and the DGP model as an example of extra-dimensional implementations.	contribution 0.68	0.08	0.02	asserted 0.68
s3	I will then briefly describe the Galileon models and their very recent multifield and curved space extensions - a class of four-dimensional effective field theories encoding extra dimensional modifications to gravity.	contribution 0.71	0.15	0.04	asserted 0.91
s4	This article is dedicated to the career of my friend and former colleague, Joshua Goldberg, and is written to appear in his festschrift.	background 0.89	0.10	0.01	asserted 0.94

What kind of paper the classifier reports this is: review 1.00 · evidence from literature 0.99.

What was examined, and what was not

sources read

arXiv listing abstract v1

not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

not run

S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

The discovery of cosmic acceleration has raised the intriguing possibility that we are witnessing the first breakdown of General Relativity on cosmological scales. In this article I will briefly review current attempts to construct a theoretically consistent and observationally viable modification of gravity that is capable of describing the accelerating universe. I will discuss f(R) models, and their obvious extensions, and the DGP model as an example of extra-dimensional implementations. I will then briefly describe the Galileon models and their very recent multifield and curved space extensions - a class of four-dimensional effective field theories encoding extra dimensional modifications to gravity. This article is dedicated to the career of my friend and former colleague, Joshua Goldberg, and is written to appear in his festschrift.

Human review

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How the literature uses it

1 arXiv paper cite this in 1 sentence

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it

Cites it as background 1 paper

Two major efforts for the acceleration mechanism have been adding a new substance (termed as dark energy) or reformulating gravity (modifying general relativity) [ref] .

Growth of perturbations in nonlocal gravity with non-$\Lambda$CDM background · Introduction · 0.96

What it cites · 16 sentences without a confident label

Builds on 6 papers

It is natural to consider generalizing the action of [ref] to include other curvature invariants [ref] .

Is Cosmic Speed-Up Due to New Gravitational Physics? · Extensions: Higher-Order Curvature Invariants · 0.90
It is natural to consider generalizing the action of [ref] to include other curvature invariants [ref] .

The Cosmology of Generalized Modified Gravity Models · Extensions: Higher-Order Curvature Invariants · 0.90
These galileon actions can be generalized to the multi-field case, where there is a multiplet $π^I$ of fields [ref] .

Bi-galileon theory I: motivation and formulation · Galileons · 0.84

Uses the method or tool of 1 paper

The prescription of [ref] is then as follows: on the 4-dimensional brane, we may add the first two Lovelock terms, namely the cosmological constant term $∼√(-g̅)$ and the Einstein-Hilbert term $∼√(-g̅)R[g̅]$.

DBI and the Galileon reunited · Galileons on Curved Spaces · 0.95

Cites as background 8 papers

It may be that curvatures and length scales in the observable universe are only now reaching values at which an infrared modification of gravity can make itself apparent by driving self-acceleration (for reviews see [ref] ).

Dark Energy and the Accelerating Universe · Introduction · 0.91
It may be that curvatures and length scales in the observable universe are only now reaching values at which an infrared modification of gravity can make itself apparent by driving self-acceleration (for reviews see [ref] ).

The Physics of Cosmic Acceleration · Introduction · 0.91
It may be that curvatures and length scales in the observable universe are only now reaching values at which an infrared modification of gravity can make itself apparent by driving self-acceleration (for reviews see [ref] ).

Approaches to Understanding Cosmic Acceleration · Introduction · 0.91

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