8 papers
Gravitational wave constraints on the Paneitz operator
Robin Valtin, Alexander Ganz, Guillem Domènech
The Paneitz operator is a dimension-4 conformally invariant fourth-order differential operator that has recently attracted attention for possible cancellations of the vacuum energy…
Unique gravitational wave signatures of GLPV scalar-tensor theories
Guillem Domènech, Alexander Ganz, Mohammad Ali Gorji +1
We study gravitational waves induced by scalar primordial fluctuations in Gleyzes-Langlois-Piazza-Vernizzi (GLPV), beyond Horndeski, scalar-tensor theories. We uncover, at the leve…
Scalar-assisted magnetogenesis during the radiation-dominated epoch
Alexander Ganz, Chunshan Lin, Mian Zhu
We propose a novel mechanism to generate primordial magnetic fields (PMFs) strong enough to explain the observed cosmic magnetic fields. We employ a scalar field charged under U(1)…
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…
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…