Research
[Probing the Dark Universe with Gravitational Waves]
Dark Energy and Gravitational Waves
Gravitational wave astronomy can probe fundamental properties of gravity and provides novel tests of dark energy. The recent measurement of the GW speed following GW170817 is an excellent example of the immense potential available to GWs tests of gravity and cosmology. My research focuses on searching for the fundamental nature of dark energy through its possible effects in the propagation of GWs. We have recently presented a review about GW tests of dark energy.
Publications:
-
Dark Energy in light of Multi-Messenger Gravitational-Wave astronomy
JM. Ezquiaga and M. Zumalacárregui. arXiv1807.09241
-
Dark Energy after GW170817: dead ends and the road ahead
JM. Ezquiaga and M. Zumalacárregui. Phys.Rev.Lett. 119.251304 (2017) (Editors suggestion)
-
Speed of Gravitational Waves and the Fate of Scalar-Tensor Gravity
D. Bettoni, JM. Ezquiaga, K. Hinterbichler and M. Zumalacárregui. Phys.Rev.D 95, 084029 (2017)
​
​
Primordial Black-Holes and the Early Universe
Black-holes are natural Dark Matter candidate. They only interact gravitationally, they move at non-relativistic speeds and they are basically collisionless due to their small size. If they are abundant enough and if they originated early enough in the history of the universe, they could constitute a significant fraction of the DM. I am interested in the gravitational wave signatures that Primordial Black-Holes can imprint and how we can use this information to learn about their formation mechanisms in the Early Universe. This could open a unique window to test the primordial power spectrum at small-scales.
Publications:
-
Quantum diffusion beyond slow-roll: implications for primordial black-hole production
JM. Ezquiaga and J. García-Bellido. JCAP 1808 (2018) 018
-
Primordial Black Hole production in Critical Higgs Inflation
JM. Ezquiaga, J. García-Bellido and E. Ruiz-Morales. Phys.Lett.B 776. 345-349 (2018)
​
​
Constructing Gravity theories
General Relativity is a very successful theory of gravity tested with high accuracy between the laboratory scales and the solar system. However, both gravitational wave interferometers and large scale structure surveys are pushing GR to new limits. In this sense, it is relevant to envision what possible extensions of GR can be constructed. I have developed a formalism based on the language of differential forms that can be used for this task. Within this language, one can very naturally describe Horndeski theory, Generalized Proca or Massive Gravity.
Publications:
-
Field redefinitions in theories beyond Einstein gravity using the language of differential forms
JM. Ezquiaga, J. García-Bellido and M. Zumalacárregui. Phys. Rev. D 95, 084039
-
Towards the most general scalar-tensor theories of gravity: a unified approach in the language of differential forms
JM. Ezquiaga, J. García-Bellido and M. Zumalacárregui. Phys. Rev. D 94, 024005
​
​