Outputs (42)

Do we live on the End of the World? (2025)
Journal Article
Muntz, B., Padilla, A., & Saffin, P. M. (2025). Do we live on the End of the World?. Journal of High Energy Physics, 2025(5), Article 6. https://doi.org/10.1007/jhep05%282025%29006

We propose a scenario of a de Sitter universe living on an End-of-the-World brane. Motivated by the Swampland programme and in particular the Cobordism Conjecture, we consider a compact region of AdS5 nucleating from nothing, with a dS4 living on its... Read More about Do we live on the End of the World?.

de Sitter vacua in O(d,d) invariant cosmology (2024)
Journal Article
Liu, Y., Padilla, A., Saffin, P. M., & Smith, R. G. C. (2024). de Sitter vacua in O(d,d) invariant cosmology. Physical Review D, 110(6), Article 063522. https://doi.org/10.1103/physrevd.110.063522

We perform a thorough analysis of de Sitter solutions in O⁡(𝑑,𝑑) invariant cosmologies. Starting with a homogeneous and isotropic framework we examine conditions for the existence of such solutions to the vacuum field equations, nonperturbative in 𝛼′... Read More about de Sitter vacua in O(d,d) invariant cosmology.

Smoothed asymptotics: from number theory to QFT (2024)
Journal Article
Padilla, A., & Smith, R. G. (2024). Smoothed asymptotics: from number theory to QFT. Physical Review D, 110(2), Article 025010. https://doi.org/10.1103/PhysRevD.110.025010

Inspired by the method of smoothed asymptotics developed by Terence Tao, we introduce a new ultraviolet regularisation scheme for loop integrals in quantum field theory which we call η regularisation. This reveals a connection between the elimination... Read More about Smoothed asymptotics: from number theory to QFT.

Ringdowns for black holes with scalar hair: The large mass case (2024)
Journal Article
D’Addario, G., Padilla, A., Saffin, P. M., Sotiriou, T. P., & Spiers, A. (2024). Ringdowns for black holes with scalar hair: The large mass case. Physical Review D, 109(8), Article 084046. https://doi.org/10.1103/physrevd.109.084046

Deviations from general relativity can alter the quasinormal mode (QNM) ringdown of perturbed black holes. It is known that a shift-symmetric (hence massless) scalar can only introduce black hole hair if it couples to the Gauss-Bonnet invariant, in w... Read More about Ringdowns for black holes with scalar hair: The large mass case.

The cosmological constant is probably still zero (2023)
Journal Article
Liu, Y., Padilla, A., & Pedro, F. G. (2023). The cosmological constant is probably still zero. Journal of High Energy Physics, 2023(10), Article 14. https://doi.org/10.1007/JHEP10%282023%29014

We consider a wide class of four-dimensional effective field theories in which gravity is coupled to multiple four-forms and their dual scalar fields, with membrane sources charged under the corresponding three-form potentials. Four-form flux, quanti... Read More about The cosmological constant is probably still zero.

CMB constraints on monodromy inflation at strong coupling (2022)
Journal Article
Copeland, E. J., Cunillera, F., Moss, A., & Padilla, A. (2022). CMB constraints on monodromy inflation at strong coupling. Journal of Cosmology and Astroparticle Physics, 2022(09), Article 080. https://doi.org/10.1088/1475-7516/2022/09/080

We carry out a thorough numerical examination of field theory monodromy inflation at strong coupling. We perform an MCMC analysis using a Gaussian likelihood, fitting multiparameter models using CMB constraints on the spectral index and the tensor to... Read More about CMB constraints on monodromy inflation at strong coupling.

Generalised scalar-tensor theories and self-tuning (2022)
Journal Article
Copeland, E. J., Ghataore, S., Niedermann, F., & Padilla, A. (2022). Generalised scalar-tensor theories and self-tuning. Journal of Cosmology and Astroparticle Physics, 2022(3), Article 004. https://doi.org/10.1088/1475-7516/2022/03/004

We explore a family of generalised scalar-tensor theories that exhibit self-tuning to low scale anti de Sitter vacua, even in the presence of a large cosmological constant. We are able to examine the linearised fluctuations about these vacua and comp... Read More about Generalised scalar-tensor theories and self-tuning.

Quintessence and the Swampland: The Parametrically Controlled Regime of Moduli Space (2022)
Journal Article
Cicoli, M., Cunillera, F., Padilla, A., & Pedro, F. G. (2022). Quintessence and the Swampland: The Parametrically Controlled Regime of Moduli Space. Fortschritte der Physik / Progress of Physics, 70(4), Article 2200009. https://doi.org/10.1002/prop.202200009

We provide evidence that slow roll is not possible in any parametrically controlled regime of the moduli space of string theory. This is proven in full generality in the asymptotic limit of the moduli space of type II and heterotic Calabi-Yau compact... Read More about Quintessence and the Swampland: The Parametrically Controlled Regime of Moduli Space.

Quintessence and the Swampland: The Numerically Controlled Regime of Moduli Space (2022)
Journal Article
Cicoli, M., Cunillera, F., Padilla, A., & Pedro, F. G. (2022). Quintessence and the Swampland: The Numerically Controlled Regime of Moduli Space. Fortschritte der Physik / Progress of Physics, 70(4), Article 2200008. https://doi.org/10.1002/prop.202200008

We provide a detailed discussion of the main theoretical and phenomenological challenges of quintessence model building in any numerically controlled regime of the moduli space of string theory. We argue that a working quintessence model requires a l... Read More about Quintessence and the Swampland: The Numerically Controlled Regime of Moduli Space.

Quadratic curvature corrections to stringy effective actions and the absence of de Sitter vacua (2022)
Journal Article
Cunillera, F., Emond, W. T., Lehébel, A., & Padilla, A. (2022). Quadratic curvature corrections to stringy effective actions and the absence of de Sitter vacua. Journal of High Energy Physics, 2022(2), Article 12. https://doi.org/10.1007/jhep02%282022%29012

We investigate the combined effect of fluxes and higher-order curvature corrections, in the form of the Gauss-Bonnet term, on the existence of de Sitter vacua in a heterotic string inspired framework, compactified on spheres and tori. We first gain s... Read More about Quadratic curvature corrections to stringy effective actions and the absence of de Sitter vacua.