Outputs (36)

Shadows and properties of spin-induced scalarized black holes with and without a Ricci coupling (2024)
Journal Article
Fernandes, P. G., Burrage, C., Eichhorn, A., & Sotiriou, T. P. (2024). Shadows and properties of spin-induced scalarized black holes with and without a Ricci coupling. Physical Review D, 109(10), Article 104033. https://doi.org/10.1103/physrevd.109.104033

In this work, we explore the properties and shadows of spin-induced scalarized black holes, as well as investigate how a Ricci coupling influences them. Our findings reveal significant deviations from the Kerr metric in terms of the location and geod... Read More about Shadows and properties of spin-induced scalarized black holes with and without a Ricci coupling.

Using machine learning to optimise chameleon fifth force experiments (2024)
Journal Article
Briddon, C., Burrage, C., Moss, A., & Tamosiunas, A. (2024). Using machine learning to optimise chameleon fifth force experiments. Journal of Cosmology and Astroparticle Physics, 2024(2), Article 11. https://doi.org/10.1088/1475-7516/2024/02/011

The chameleon is a theorised scalar field that couples to matter and possess a screening mechanism, which weakens observational constraints from experiments performed in regions of higher matter density. One consequence of this screening mechanism is... Read More about Using machine learning to optimise chameleon fifth force experiments.

Higgs-induced screening mechanisms in scalar-tensor theories (2023)
Journal Article
Burrage, C., & Millington, P. (2024). Higgs-induced screening mechanisms in scalar-tensor theories. Annals of the New York Academy of Sciences, 1531(1), 95-103. https://doi.org/10.1111/nyas.15092

We consider the theory of a light conformally coupled scalar field, that is, one that is coupled directly to the Ricci scalar of the gravitational sector. This theory can be written equivalently as one of a light scalar that is coupled to the Standar... Read More about Higgs-induced screening mechanisms in scalar-tensor theories.

Spinning black holes with axion hair (2023)
Journal Article
Burrage, C., Fernandes, P. G. S., Brito, R., & Cardoso, V. (2023). Spinning black holes with axion hair. Classical and Quantum Gravity, 40(20), Article 205021. https://doi.org/10.1088/1361-6382/acf9d6

In this work we construct and analyze non-perturbative stationary and axially-symmetric black hole solutions in general relativity coupled to an electromagnetic and an axion field. The axion field is coupled to the electromagnetic field, which leads... Read More about Spinning black holes with axion hair.

Chameleon screening in cosmic voids (2022)
Journal Article
Tamosiunas, A., Briddon, C., Burrage, C., Cutforth, A., Moss, A., & Vincent, T. (2022). Chameleon screening in cosmic voids. Journal of Cosmology and Astroparticle Physics, 2022(11), Article 056. https://doi.org/10.1088/1475-7516/2022/11/056

A key goal in cosmology in the upcoming decade will be to form a better understanding of the accelerated expansion of the Universe. Upcoming surveys, such as the Vera C. Rubin Observatory's 10-year Legacy Survey of Space and Time (LSST), Euclid and t... Read More about Chameleon screening in cosmic voids.

SELCIE: a tool for investigating the chameleon field of arbitrary sources (2021)
Journal Article
Briddon, C., Burrage, C., Moss, A., & Tamosiunas, A. (2021). SELCIE: a tool for investigating the chameleon field of arbitrary sources. Journal of Cosmology and Astroparticle Physics, 2021(12), 1-24. https://doi.org/10.1088/1475-7516/2021/12/043

The chameleon model is a modified gravity theory that introduces an additional scalar field that couples to matter through a conformal coupling. This `chameleon field' possesses a screening mechanism through a nonlinear self-interaction term which al... Read More about SELCIE: a tool for investigating the chameleon field of arbitrary sources.

Fifth-force screening around extremely compact sources (2021)
Journal Article
Burrage, C., Elder, B., Millington, P., Saadeh, D., & Thrussell, B. (2021). Fifth-force screening around extremely compact sources. Journal of Cosmology and Astroparticle Physics, 2021(August 2021), Article JCAP08(2021)052. https://doi.org/10.1088/1475-7516/2021/08/052

Many non-linear scalar field theories possess a screening mechanism that can suppress any associated fifth force in dense environments. As a result, these theories can evade local experimental tests of new forces. Chameleon-like screening, which occu... Read More about Fifth-force screening around extremely compact sources.

Charting galactic accelerations: when and how to extract a unique potential from the distribution function (2021)
Journal Article
An, J., Naik, A. P., Evans, N. W., & Burrage, C. (2021). Charting galactic accelerations: when and how to extract a unique potential from the distribution function. Monthly Notices of the Royal Astronomical Society, 506(4), 5721-5730. https://doi.org/10.1093/mnras/stab2049

The advent of data sets of stars in the Milky Way with 6D phase-space information makes it possible to construct empirically the distribution function (DF). Here, we show that the accelerations can be uniquely determined from the DF using the collisi... Read More about Charting galactic accelerations: when and how to extract a unique potential from the distribution function.

φenics: Vainshtein screening with the finite element method (2021)
Journal Article
Braden, J., Burrage, C., Elder, B., & Saadeh, D. (2021). φenics: Vainshtein screening with the finite element method. Journal of Cosmology and Astroparticle Physics, 2021(03), Article 010. https://doi.org/10.1088/1475-7516/2021/03/010

Within the landscape of modified theories of gravity, progress in understanding the behaviour of, and developing tests for, screening mechanisms has been hindered by the complexity of the field equations involved, which are nonlinear in nature and ch... Read More about φenics: Vainshtein screening with the finite element method.

Massive Galileons and Vainshtein screening (2021)
Journal Article
Burrage, C., Coltman, B., Padilla, A., Saadeh, D., & Wilson, T. (2021). Massive Galileons and Vainshtein screening. Journal of Cosmology and Astroparticle Physics, 2021(02), Article 050. https://doi.org/10.1088/1475-7516/2021/02/050

The Vainshtein screening mechanism relies on nonlinear interaction terms becoming dominant close to a compact source. However, theories displaying this mechanism are generally understood to be low-energy theories: it is unclear that operators emergin... Read More about Massive Galileons and Vainshtein screening.