17 citations · 18 across the 8 of their papers we have counts for
8 papers
Rolling Galileons: Evolving Braiding Strength for Viable Dark Energy
James Hallam, Krishna Naidoo, Sergi Sirera +1
Motivated by growing observational indications that dark energy may be dynamical, we introduce Rolling Galileon gravity: a minimal shift-symmetry-breaking extension of the cubic Ga…
Constraints on Horndeski gravity with phantom crossing
Krishna Naidoo, James Hallam, Tessa Baker +1
Gravity models in which the dark energy equation of state crosses , also known as the phantom divide, have received extensive interest due to recent analyses favouring this b…
A Master Equation for Screening in Luminal Horndeski Gravity
Sergi Sirera, Tessa Baker, James Hallam +1
Determining the active screening mechanism from a general scalar-tensor Lagrangian remains a challenging problem. As a diagnostic tool, we present a systematic study of nonlinear c…
Testing Dark Energy with Black Hole Ringdown
Laurens Smulders, Johannes Noller, Sergi Sirera
We show that dynamical dark energy theories can imprint modifications on the quasi-normal mode (QNM) spectrum characterising black hole ringdown. The time dependence of dyna…
Black hole ringdown tests of gravity
Sergi Sirera
Understanding gravity is at the heart of some of the biggest questions in modern physics. While General Relativity (GR) is a theoretically unique and experimentally well-tested fra…
Inverting no-hair theorems: How requiring General Relativity solutions restricts scalar-tensor theories
Hajime Kobayashi, Shinji Mukohyama, Johannes Noller +3
Black hole solutions in general scalar-tensor theories are known to permit hair, i.e. non-trivial scalar profiles and/or metric solutions different from the ones of General Relativ…
Stability and quasinormal modes for black holes with time-dependent scalar hair
Sergi Sirera, Johannes Noller
We investigate black hole solutions with time-dependent (scalar) hair in scalar-tensor theories. Known exact solutions exist for such theories at the background level, where the me…
Testing the Speed of Gravity with Black Hole Ringdown
Sergi Sirera, Johannes Noller
We investigate how the speed of gravitational waves, , can be tested by upcoming black hole ringdown observations. We do so in the context of hairy black hole solutions, wh…