All Outputs (39)

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. C. (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 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.

A stringy perspective on the coincidence problem (2021)
Journal Article
Cunillera, F., & Padilla, A. (2021). A stringy perspective on the coincidence problem. Journal of High Energy Physics, 2021(10), Article 55. https://doi.org/10.1007/JHEP10%282021%29055

We argue that, for string compactifications broadly consistent with swampland constraints, dark energy is likely to signal the beginning of the end of our universe as we know it, perhaps even through decompactification, with possible implications for... Read More about A stringy perspective on the coincidence problem.

Deconstructing higher order clockwork gravity (2021)
Journal Article
Avgoustidis, A., Niedermann, F., Padilla, A., & Saffin, P. M. (2021). Deconstructing higher order clockwork gravity. Physical Review D, 103(12), Article 124007. https://doi.org/10.1103/physrevd.103.124007

We consider the higher order clockwork theory of gravitational interactions, whereby a number of gravitons are coupled together with TeV strength, but nevertheless generate a Planck scale coupling to matter without the need for a dilaton. It is shown... Read More about Deconstructing higher order clockwork gravity.

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.

Unimodular vs nilpotent superfield approach to pure dS supergravity (2021)
Journal Article
Bansal, S., Nagy, S., Padilla, A., & Zavala, I. (2021). Unimodular vs nilpotent superfield approach to pure dS supergravity. Journal of High Energy Physics, 2021(1), Article 146 (2021). https://doi.org/10.1007/jhep01%282021%29146

Recent progress in understanding de Sitter spacetime in supergravity and string theory has led to the development of a four dimensional supergravity with spontaneously broken supersymmetry allowing for de Sitter vacua, also called de Sitter supergrav... Read More about Unimodular vs nilpotent superfield approach to pure dS supergravity.

Dark energy loopholes some time after GW170817 (2020)
Journal Article
Bordin, L., Copeland, E. J., & Padilla, A. (2020). Dark energy loopholes some time after GW170817. Journal of Cosmology and Astroparticle Physics, 2020(11), Article 063. https://doi.org/10.1088/1475-7516/2020/11/063

We revisit the constraints on scalar tensor theories of modified gravity following the purge of GW170817. We pay particular attention to dynamical loopholes where the anomalous speed of propagation of the gravitational wave can vanish on-shell, when... Read More about Dark energy loopholes some time after GW170817.

Cosmological consequences of Omnia Sequestra (2019)
Journal Article
Coltman, B., Li, Y., & Padilla, A. (2019). Cosmological consequences of Omnia Sequestra. Journal of Cosmology and Astroparticle Physics, 2019(06), Article 017. https://doi.org/10.1088/1475-7516/2019/06/017

Vacuum energy sequestering is a mechanism for cancelling off the radiative corrections to vacuum energy. The most comprehensive low energy model, proposed in [1], has the ability to cancel off radiative corrections to vacuum energy for loops of both... Read More about Cosmological consequences of Omnia Sequestra.

Dark Energy after GW170817 Revisited (2019)
Journal Article
Copeland, E. J., Kopp, M., Padilla, A., Saffin, P. M., & Skordis, C. (2019). Dark Energy after GW170817 Revisited. Physical Review Letters, 122(6), Article 061301. https://doi.org/10.1103/physrevlett.122.061301

We revisit the status of scalar-tensor theories with applications to dark energy in the aftermath of the gravitational wave signal GW170817 and its optical counterpart GRB170817A. At the level of the cosmological background, we identify a class of th... Read More about Dark Energy after GW170817 Revisited.

Monodromy inflation and an emergent mechanism for stabilising the cosmological constant (2019)
Journal Article
Padilla, A. (2019). Monodromy inflation and an emergent mechanism for stabilising the cosmological constant. Journal of High Energy Physics, 2019(1), Article 175. https://doi.org/10.1007/jhep01%282019%29175

We show that a pair of field theory monodromies in which the shift symmetry is broken by small, well motivated deformations, naturally incorporates a mechanism for cancelling off radiative corrections to the cosmological constant. The lighter monodro... Read More about Monodromy inflation and an emergent mechanism for stabilising the cosmological constant.

Non-perturbative aspects of galileon duality (2018)
Journal Article
Millington, P., Niedermann, F., & Padilla, A. (in press). Non-perturbative aspects of galileon duality. European Physical Journal C: Particles and Fields, 78(7), https://doi.org/10.1140/epjc/s10052-018-6029-0

We study quantum aspects of the galileon duality, especially in the case of a particular interacting galileon theory that is said to be dual to a free theory through the action of a simultaneous field and coordinate transformation. This would appear... Read More about Non-perturbative aspects of galileon duality.

Vainshtein in the UV and a Wilsonian analysis of derivatively coupled scalars (2018)
Journal Article
Padilla Antonio, A., & Saltas, I. (2018). Vainshtein in the UV and a Wilsonian analysis of derivatively coupled scalars. Journal of Cosmology and Astroparticle Physics, 2018(6), https://doi.org/10.1088/1475-7516/2018/06/039

In the first part of this paper we critically examine the ultra-violet implications of theories that exhibit Vainshtein screening, taking into account both the standard Wilsonian perspective as well as more exotic possibilities. Aspects of this discu... Read More about Vainshtein in the UV and a Wilsonian analysis of derivatively coupled scalars.

An étude on global vacuum energy sequester (2017)
Journal Article
D’Amico, G., Kaloper, N., Padilla, A., Stefanyszyn, D., Westphal, A., & Zahariade, G. (2017). An étude on global vacuum energy sequester. Journal of High Energy Physics, 2017(9), Article 74. https://doi.org/10.1007/JHEP09%282017%29074

Recently two of the authors proposed a mechanism of vacuum energy sequester as a means of protecting the observable cosmological constant from quantum radiative corrections. The original proposal was based on using global Lagrange multipliers, but la... Read More about An étude on global vacuum energy sequester.

Probing scalar effective field theories with the soft limits of scattering amplitudes (2017)
Journal Article
Padilla, A., Stefanyszyn, D., & Wilson, T. (2017). Probing scalar effective field theories with the soft limits of scattering amplitudes. Journal of High Energy Physics, 2017(4), https://doi.org/10.1007/JHEP04%282017%29015

We investigate the soft behaviour of scalar effective field theories (EFTs) when there is a number of distinct derivative power counting parameters, ρ1 < ρ2 < . . . < ρQ. We clarify the notion of an enhanced soft limit and use these to extend the sco... Read More about Probing scalar effective field theories with the soft limits of scattering amplitudes.