76 citations · 506 across the 18 of their papers we have counts for
13 papers · 1 filter
Dynamical Tidal Locking Theory: A new source of the Spin of Dark Matter Halos
E. Ebrahimian, A. A. Abolhasani
We revisit the question of what mechanism is responsible for the spins of halos of dark matter. The answer to this question is of high importance for modeling galaxy intrinsic alig…
Cherenkov in the Sky: Measuring the Sound Speed of Primordial Scalar Fluctuations
Ali Akbar Abolhasani, Sadra Jazayeri
We consider production of additional relativistic particles coupled to the inflaton. We show that the imprints of these particles on the spectrum of primordial perturbations can be…
Resonant Reconciliation of Convex Models and the Planck
Ali Akbar Abolhasani, M. M. Sheikh-Jabbari
We consider single field chaotic inflationary models plus a cosine modulation term, as in axion monodromy models, and augment it by a light scalar field with similar cosine couplin…
Single-Field Consistency relation and -Formalism
Ali Akbar Abolhasani, Misao Sasaki
According to the equivalence principal, the long wavelength perturbations must not have any dynamical effect on the short scale physics up to . Their effect…
Primordial Statistical Anisotropies: The Effective Field Theory Approach
Ali Akbar Abolhasani, Mohammad Akhshik, Razieh Emami +1
In this work we present the effective field theory of primordial statistical anisotropies generated during anisotropic inflation involving a background gauge field. Besides…
Fingerprints of Anomalous Primordial Universe on the Abundance of Large Scale Structures
Shant Baghram, Ali Akbar Abolhasani, Hassan Firouzjahi +1
We study the predictions of anomalous inflationary models on the abundance of structures in large scale structure observations. The anomalous features encoded in primordial curvatu…
CMB Hemispherical Asymmetry: Long Mode Modulation and non-Gaussianity
Mohammad Hossein Namjoo, Ali Akbar Abolhasani, Shant Baghram +1
The observed hemispherical asymmetry in CMB map can be explained by modulation from a long wavelength super horizon mode which non-linearly couples to the CMB modes. We address the…
Asymmetric Sky from the Long Mode Modulations
Ali Akbar Abolhasani, Shant Baghram, Hassan Firouzjahi +1
The observed dipole asymmetry in Cosmic Microwave Background radiation may have originated from the modulations of super-horizon long wavelength modes. In this work we unveil diffe…
δN Formalism in Anisotropic Inflation and Large Anisotropic Bispectrum and Trispectrum
Ali Akbar Abolhasani, Razieh Emami, Javad T. Firouzjaee +1
We present a consistent δN formalism for curvature perturbations in anisotropic cosmological backgrounds. We employ our δN formalism to calculate the power spectrum, the bispectrum…
Effects of Variable Newton Constant During Inflation
Ali Akbar Abolhasani, Hassan Firouzjahi, Mahdiyar Noorbala
In this paper the effects of time-dependent Newton constant G during inflation are studied. We present the formalism of curvature perturbations in an inflationary system with a tim…
Local Features with Large Spiky non-Gaussianities during Inflation
Ali Akbar Abolhasani, Hassan Firouzjahi, Shahram Khosravi +1
We provide a dynamical mechanism to generate localized features during inflation. The local feature is due to a sharp waterfall phase transition which is coupled to the inflaton fi…
Curvature perturbation and waterfall dynamics in hybrid inflation
Ali Akbar Abolhasani, Hassan Firouzjahi, Misao Sasaki
We investigate the parameter spaces of hybrid inflation model with special attention paid to the dynamics of waterfall field and curvature perturbations induced from its quantum fl…
Curvature Perturbations and non-Gaussianities from Waterfall Phase Transition during Inflation
Ali Akbar Abolhasani, Hassan Firouzjahi, Mohammad Hossein Namjoo
We consider a variant of hybrid inflation where the waterfall phase transition happens during inflation. By adjusting the parameters associated with the mass of the waterfall field…