383 citations · 794 across the 8 of their papers we have counts for
8 papers
Effective theories of single field inflation when heavy fields matter
Ana Achucarro, Jinn-Ouk Gong, Sjoerd Hardeman +2
We compute the low energy effective field theory (EFT) expansion for single-field inflationary models that descend from a parent theory containing multiple other scalar fields. By…
Decoupling limits in multi-sector supergravities
Ana Achúcarro, Sjoerd Hardeman, Johannes M. Oberreuter +2
Conventional approaches to cosmology in supergravity assume the existence of multiple sectors that only communicate gravitationally. In principle these sectors decouple in the limi…
The everpresent eta-problem: knowledge of all hidden sectors required
Sjoerd Hardeman, Johannes M. Oberreuter, Gonzalo A. Palma +2
We argue that the eta-problem in supergravity inflation cannot be solved without knowledge of the ground state of hidden sectors that are gravitationally coupled to the inflaton. I…
Features of heavy physics in the CMB power spectrum
Ana Achúcarro, Jinn-Ouk Gong, Sjoerd Hardeman +2
The computation of the primordial power spectrum in multi-field inflation models requires us to correctly account for all relevant interactions between adiabatic and non-adiabatic…
Mass hierarchies and non-decoupling in multi-scalar field dynamics
Ana Achúcarro, Jinn-Ouk Gong, Sjoerd Hardeman +2
In this work we study the effects of field space curvature on scalar field perturbations around an arbitrary background field trajectory evolving in time. Non-trivial imprints of t…
Quark matter influence on observational properties of compact stars
Sjoerd Hardeman
Densities in compact stars may be such that quarks are no longer confined in hadrons, but instead behave as weakly interacting particles. In this regime perturbative calculations a…