6 papers
On the adiabatic initial conditions for a particle gas in cosmology
Guillem Domènech
In view of recent interest in the role of "dark" radiation in cosmology, such as cosmic gravitational waves, sterile neutrinos, and dark photons, we clarify the definition of adiab…
Apparent Lorentz violation from disformally coupled ultralight dark matter
Guillem Domènech, Apostolos Tsabodimos, Nathaniel Sherrill +2
We study the impact of general disformal metric transformations on fermions, which shift the gravitational metric by an additional rank-2 tensor. This tensor can in principle be co…
On the consistent disformal couplings to fermions
Guillem Domènech, Alexander Ganz, Apostolos Tsabodimos
Disformal couplings to fermions lead to a unique derivative coupling to the axial fermionic current, which contains higher derivatives in general. We derive general conditions on c…
Gravitational waves induced by matter isocurvature in general cosmologies
Guillem Domènech, Jan Tränkle
The expansion history and content of the Universe between the end of inflation and the onset of Big Bang Nucleosynthesis is mostly unknown. In this paper, we study gravitational wa…
Regularizing the induced GW spectrum with dissipative effects
Guillem Domènech, Jens Chluba
Finite mean free paths of light particles, like photons and neutrinos, lead to dissipative effects and damping of small-scale density fluctuations in the early universe. We study t…
Connecting Relativistic MOND Theories with Mimetic Gravity
Guillem Domènech, Alexander Ganz
We find a connection between relativistic Modified Newtonian Dynamics (MOND) theories and (scalar) mimetic gravity. We first demonstrate that any relativistic MOND model featuring…