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Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
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Classifying linearly shielded modified gravity models in effective field theory.
Lucas Lombriser1, Andy Taylor1
1Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, United Kingdom.
Physical Review Letters
|February 7, 2015
Summary
Researchers explored modified gravity and dark energy models, finding specific classes that mimic the standard cosmological model on large scales. Distinguishing these models from the standard model is challenging with current observations.
Area of Science:
- Cosmology
- Theoretical Physics
- Astrophysics
Background:
- Cosmological background evolution and perturbations are key to understanding the universe.
- Modified gravity and dark energy models offer alternatives to the standard Lambda-CDM model.
- Effective field theories provide a framework for studying these complex models.
Purpose of the Study:
- To investigate the model space of modified gravity and dark energy.
- To identify models consistent with the concordance model's background expansion and perturbation evolution.
- To assess the observational distinguishability of these models from the standard model.
Main Methods:
- Studying time-dependent operator coefficients within effective field theory.
- Analyzing cosmological background evolution and perturbations.
- Classifying modified gravity models based on their behavior at different scales.
Main Results:
- Identified three classes of modified gravity models reducing to Newtonian gravity on small scales.
- Found extensive model spaces that mimic the concordance model on subhorizon scales and background evolution.
- Demonstrated that such models exist even within Horndeski scalar-tensor gravity.
Conclusions:
- Partially shielded scenarios may help address tensions between large and small scale data.
- Distinguishing fully shielded scenarios from the concordance model is limited by cosmic variance using conventional probes.
- Novel tests of large-scale structure are needed to probe gravity in alternative theories.
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