4 papers
Cosmological perturbation theory with trinity of scalar fields
Amjad Ashoorioon, Shinji Mukohyama, Kazem Rezazadeh +1
We present an explicit formulation of cosmological perturbation theory for three-field models with a flat field space. By performing rotations to align one field with the direction…
Measuring black hole spin through gravitational lensing of pulsars
Amjad Ashoorioon, Mohammad Bagher Jahani Poshteh, Robert B. Mann
We propose a new procedure for measuring the spin of a black hole with an unprecedented accuracy based on the gravitational lensing of millisecond pulsars. We derive the basic equa…
Static horizons in cosmology
Ida M. Rasulian, Amjad Ashoorioon
Although previous results have ruled out the possibility of a static event horizon in cosmology, we present black hole and white hole metrics that retain static event horizons whil…
Cascading Dark Energy
K. Rezazadeh, A. Ashoorioon, D. Grin
The standard cosmological model is in the midst of a stress test, thanks to the tension between supernovae-based measurements of the Hubble constant and inferences of its v…