359 citations · 1.8k across the 36 of their papers we have counts for
16 papers · 1 filter
de Sitter Spacetime: Geometry, Causal Structure, and Quantum Fields
Azadeh Maleknejad, Ethan Richardson
de~Sitter spacetime plays a central role in modern cosmology, providing an excellent approximation to both inflation and the present accelerated expansion. It also offers a particu…
Stochastic Schwinger Effect: de Sitter and beyond
Lucas Vicente García-Consuegra, Azadeh Maleknejad
We develop a stochastic formulation of the Schwinger effect in de Sitter spacetime using the Schwinger--Keldysh (in-in) formalism, tailored to particle production by non-stationary…
The Stochastic Schwinger Effect
Lucas Vicente García-Consuegra, Azadeh Maleknejad
We formulate a stochastic generalisation of the Schwinger effect, extending pair production to statistically fluctuating gauge-field backgrounds. Our approach captures realistic fi…
Weyl Fermion Creation by Cosmological Gravitational Wave Background at 1-loop
Azadeh Maleknejad, Joachim Kopp
Weyl fermions of spin minimally coupled to Einstein's gravity in 4 dimensions cannot be produced purely gravitationally in an expanding Universe at tree level. Surprising…
Photon Chiral Memory Effect Stored on Celestial Sphere
Azadeh Maleknejad
This work introduces the chiral memory effect on the celestial sphere that measures the permanent change of electromagnetic fields by spin-dependent processes in bulk. Unlike the c…
Dark Fermions and Spontaneous violation in -axion Inflation
Azadeh Maleknejad
Remarkably, if was spontaneously broken in the physics of inflation, fermions would notice and remember it. Based on that, we present a new (non-thermal) mechanism for generat…
Production and Backreaction of Fermions from Axion- Gauge Fields during Inflation
Leila Mirzagholi, Azadeh Maleknejad, Kaloian D. Lozanov
gauge fields and axions can have a stable, isotropic and homogeneous configuration during inflation. However, couplings to other matter species lead to particle production,…
Schwinger Effect by an Gauge Field during Inflation
Kaloian D. Lozanov, Azadeh Maleknejad, Eiichiro Komatsu
Non-Abelian gauge fields may exist during inflation. We study the Schwinger effect by an gauge field coupled to a charged scalar doublet in a (quasi) de Sitter background a…
Tensor Adiabatic Modes and Consistency Relations with Primordial Axion-Gauge Fields
Azadeh Maleknejad
We study the tensor consistency relation in models of axion inflation with an SU(2) gauge field. In the tensor sector, we have two spin-2 modes, the standard gravity waves and the…
Chiral Gravity Waves and Leptogenesis in Inflationary Models with non-Abelian Gauge Fields
Azadeh Maleknejad
We present a leptogenesis scenario associated with inflationary models involving non-Abelian gauge fields within the standard model of particle physics (SM). We show that this clas…
Chromo-Natural Model in Anisotropic Background
A. Maleknejad, E. Erfani
In this work we study the chromo-natural inflation model in the anisotropic setup. Initiating inflation from Bianchi type-I cosmology, we analyze the system thoroughly during the s…
Slow-roll trajectories in Chromo-Natural and Gauge-flation Models, an exhaustive analysis
A. Maleknejad, M. Zarei
We present an exhaustive analysis on the classical solutions of the Chromo-natural model. We showed that starting from an arbitrary axion field value , it is possible…
Gauge Fields and Inflation
A. Maleknejad, M. M. Sheikh-Jabbari, J. Soda
The isotropy and homogeneity of the cosmic microwave background (CMB) favors "scalar driven" early Universe inflationary models. Non-scalar fields, and in particular gauge fields,…
Leptogenesis in Inflationary models with Non-Abelian Gauge Fields
Azadeh Maleknejad, Mahdiyar Noorbala, M. M. Sheikh-Jabbari
A scenario of leptogenesis was introduced in [1] which works during inflationary period within standard model of particle physics setup. In this scenario lepton number is created b…
Revisiting Cosmic No-Hair Theorem for Inflationary Settings
A. Maleknejad, M. M. Sheikh-Jabbari
In this work we revisit Wald's cosmic no-hair theorem in the context of accelerating Bianchi cosmologies for a generic cosmic fluid with non-vanishing anisotropic stress tensor and…
Gauge-flation and Cosmic No-Hair Conjecture
A. Maleknejad, M. M. Sheikh-Jabbari, Jiro Soda
Gauge-flation, inflation from non-Abelian gauge fields, was introduced in [1,2]. In this work, we study the cosmic no-hair conjecture in gauge-flation. Starting from Bianchi-type I…