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Particle level screening of scalar forces in 1+1 dimensions (2019)
Journal Article
Burrage, C., Elder, B., & Millington, P. (2019). Particle level screening of scalar forces in 1+1 dimensions. Physical Review D, 99(2), Article 024045. https://doi.org/10.1103/physrevd.99.024045

We investigate how nonlinear scalar field theories respond to point sources. Taking the symmetron as a specific example of such a theory, we solve the nonlinear equation of motion in one spatial dimension for (i) an isolated point source and (ii) two... Read More about Particle level screening of scalar forces in 1+1 dimensions.

Fifth forces, Higgs portals and broken scale invariance (2018)
Journal Article
Burrage, C., Copeland, E. J., Millington, P., & Spannowsky, M. (2018). Fifth forces, Higgs portals and broken scale invariance. Journal of Cosmology and Astroparticle Physics, 2018(11), 1-31. https://doi.org/10.1088/1475-7516/2018/11/036

© 2018 IOP Publishing Ltd and Sissa Medialab. We study the relationship between the strength of fifth forces and the origin of scale breaking in the Standard Model (SM) of particle physics. We start with a light scalar field that is conformally coupl... Read More about Fifth forces, Higgs portals and broken scale invariance.

Stellar kinematics from the symmetron fifth force in the Milky Way disk (2018)
Journal Article
O’Hare, C. A., & Burrage, C. (2018). Stellar kinematics from the symmetron fifth force in the Milky Way disk. Physical Review D, 98(6), Article 064019. https://doi.org/10.1103/PhysRevD.98.064019

It has been shown that the presence of nonminimally coupled scalar fields giving rise to a fifth force can noticeably alter dynamics on galactic scales. Such a fifth force must be screened in the Solar System but if unscreened it can have similar obs... Read More about Stellar kinematics from the symmetron fifth force in the Milky Way disk.

Laboratory constraints (2018)
Journal Article
Brax, P., Burrage, C., & Davis, A.-C. (2018). Laboratory constraints. International Journal of Modern Physics D, 1848009. https://doi.org/10.1142/s0218271818480097

We review laboratory constraints on theories of modified gravity and show that they are complementary to cosmological and astrophysical tests. We particularly focus on the environmentally dependent dilaton, as a worked example to show how such constr... Read More about Laboratory constraints.

The shape dependence of chameleon screening (2018)
Journal Article
Burrage, C., Copeland, E. J., Moss, A., & Stevenson, J. A. (2018). The shape dependence of chameleon screening. Journal of Cosmology and Astroparticle Physics, 2018(1), https://doi.org/10.1088/1475-7516/2018/01/056

Chameleon scalar fields can screen their associated fifth forces from detection by changing their mass with the local density. These models are an archetypal example of a screening mechanism, and have become an important target for both cosmological... Read More about The shape dependence of chameleon screening.

Beyond the growth rate of cosmic structure: Testing modified gravity models with an extra degree of freedom (2017)
Journal Article
Burrage, C., Parkinson, D., & Seery, D. (2017). Beyond the growth rate of cosmic structure: Testing modified gravity models with an extra degree of freedom. Physical Review D, 96(4), Article 043509. https://doi.org/10.1103/PhysRevD.96.043509

© 2017 American Physical Society. In "modified" gravity the observed acceleration of the universe is explained by changing the gravitational force law or the number of degrees of freedom in the gravitational sector. Both possibilities can be tested b... Read More about Beyond the growth rate of cosmic structure: Testing modified gravity models with an extra degree of freedom.

Radial acceleration relation from symmetron fifth forces (2017)
Journal Article
Burrage, C., Copeland, E. J., & Millington, P. (2017). Radial acceleration relation from symmetron fifth forces. Physical Review D, D95(6), Article 064050. https://doi.org/10.1103/PhysRevD.95.064050

We show that the radial acceleration relation for rotationally supported galaxies may be explained, in the absence of cold dark matter, by a nonminimally coupled scalar field, whose fifth forces are partially screened on galactic scales by the symmet... Read More about Radial acceleration relation from symmetron fifth forces.

Constraining symmetron fields with atom interferometry (2016)
Journal Article
Burrage, C., Kuribayashi-Coleman, A., Stevenson, J., & Thrussell, B. (2016). Constraining symmetron fields with atom interferometry. Journal of Cosmology and Astroparticle Physics, 2016, Article 041. https://doi.org/10.1088/1475-7516/2016/12/041

We apply the new constraints from atom-interferometry searches for screening mechanisms to the symmetron model, finding that these experiments exclude a previously unexplored region of the parameter space. We discuss the possibility of networks of do... Read More about Constraining symmetron fields with atom interferometry.

A compendium of chameleon constraints (2016)
Journal Article
Burrage, C., & Sakstein, J. (2016). A compendium of chameleon constraints. Journal of Cosmology and Astroparticle Physics, 2016(11), Article 045. https://doi.org/10.1088/1475-7516/2016/11/045

The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candida... Read More about A compendium of chameleon constraints.

Radiative screening of fifth forces (2016)
Journal Article
Burrage, C., Copeland, E. J., & Millington, P. (2016). Radiative screening of fifth forces. Physical Review Letters, 117(21), Article 211102. https://doi.org/10.1103/PhysRevLett.117.211102

© 2016 American Physical Society. We describe a symmetron model in which the screening of fifth forces arises at the one-loop level through the Coleman-Weinberg mechanism of spontaneous symmetry breaking. We show that such a theory can avoid current... Read More about Radiative screening of fifth forces.

LHC signatures of scalar dark energy (2016)
Journal Article
Burrage, C., Brax, P., Englert, C., & Spannowsky, M. (2016). LHC signatures of scalar dark energy. Physical Review D - Particles, Fields, Gravitation and Cosmology, 94, Article 084054. https://doi.org/10.1103/PhysRevD.94.084054

Scalar dark energy fields that couple to the standard model can give rise to observable signatures at the LHC. In this work, we show that tt¯+missing energy and monojet searches are suitable probes in the limit where the dark energy scalar is stable... Read More about LHC signatures of scalar dark energy.

A proposed experimental search for chameleons using asymmetric parallel plates (2016)
Journal Article
Burrage, C., Copeland, E. J., & Stevenson, J. A. (2016). A proposed experimental search for chameleons using asymmetric parallel plates. Journal of Cosmology and Astroparticle Physics, 2016(8), https://doi.org/10.1088/1475-7516/2016/08/070

Light scalar fields coupled to matter are a common consequence of theories of dark energy and attempts to solve the cosmological constant problem. The chameleon screening mechanism is commonly invoked in order to suppress the fifth forces mediated by... Read More about A proposed experimental search for chameleons using asymmetric parallel plates.

Disformal transformations on the CMB (2016)
Journal Article
Burrage, C., Cespedes, S., & Davis, A.-C. (2016). Disformal transformations on the CMB. Journal of Cosmology and Astroparticle Physics, 2016, https://doi.org/10.1088/1475-7516/2016/08/024

In this work we study the role of disformal transformation on cosmological backgrounds and its relation to the speed of sound for tensor modes. A speed different from one for tensor modes can arise in several contexts, such as Galileons theories or m... Read More about Disformal transformations on the CMB.

Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings (2016)
Journal Article
van de Bruck, C., Burrage, C., & Morrice, J. (2016). Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings. Journal of Cosmology and Astroparticle Physics, 2016(8), Article 003. https://doi.org/10.1088/1475-7516/2016/08/003

The simplest way to modify gravity is to extend the gravitational sector to include an additional scalar degree of freedom. The most general metric that can be built in such a theory includes disformal terms, so that standard model fields move on a m... Read More about Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings.

The speed of Galileon gravity (2016)
Journal Article
Brax, P., Burrage, C., & Davis, A.-C. (2016). The speed of Galileon gravity. Journal of Cosmology and Astroparticle Physics, 2016(3), Article 004. https://doi.org/10.1088/1475-7516/2016/03/004

We analyse the speed of gravitational waves in coupled Galileon models with an equation of state ωphgr=−1 now and a ghost-free Minkowski limit. We find that the gravitational waves propagate much faster than the speed of light unless these models are... Read More about The speed of Galileon gravity.

Disformal dark energy at colliders (2015)
Journal Article
Brax, P., Burrage, C., & Englert, C. (2015). Disformal dark energy at colliders. Physical Review D, D92(4), Article 044036. https://doi.org/10.1103/PhysRevD.92.044036

Disformally coupled, light scalar fields arise in many of the theories of dark energy and modified gravity that attempt to explain the accelerated expansion of the Universe. They have proved difficult to constrain with precision tests of gravity beca... Read More about Disformal dark energy at colliders.

Using atom interferometry to detect dark energy (2015)
Journal Article
Burrage, C., & Copeland, E. J. (in press). Using atom interferometry to detect dark energy. Contemporary Physics, 57(2), https://doi.org/10.1080/00107514.2015.1060058

We review the tantalising prospect that the first evidence for the dark energy driving the observed acceleration of the Universe on giga-parsec scales may be found through metre scale laboratory based atom interferometry experiments. To do that, we f... Read More about Using atom interferometry to detect dark energy.

Shape dependence of Vainshtein screening (2015)
Journal Article
Bloomfield, J. K., Burrage, C., & Davis, A.-C. (2015). Shape dependence of Vainshtein screening. Physical Review D, D91(8), Article 083510. https://doi.org/10.1103/PhysRevD.91.083510

Scalar field theories that possess a Vainshtein mechanism are able to dynamically suppress the associated fifth forces in the presence of massive sources through derivative nonlinearities. The resulting equations of motion for the scalar are highly n... Read More about Shape dependence of Vainshtein screening.

Ellipticity weakens chameleon screening (2015)
Journal Article
Burrage, C., Copeland, E. J., & Stevenson, J. (2015). Ellipticity weakens chameleon screening. Physical Review D, D91(6), Article 065030. https://doi.org/10.1103/PhysRevD.91.065030

The chameleon mechanism enables a long-range fifth force to be screened in dense environments when nontrivial self-interactions of the field cause its mass to increase with the local density. To date, chameleon fifth forces have mainly been studied f... Read More about Ellipticity weakens chameleon screening.