activity
20172026
most citedThermal History of the Early Universe and Primordial Gravitational Waves from Induced Scalar Perturbations

78 citations · 387 across the 18 of their papers we have counts for

collaborators

26 papers

hep-ph2026

Gravitational Waves from Multiple First-Order Phase Transitions in a Scenario with Early Matter Domination

Rouzbeh Allahverdi, Fazlollah Hajkarim

Non-standard cosmological histories with epochs of early matter domination (EMD) arise in various top-down models of the early universe. Typically, in the latter stage of EMD, temp…

hep-ph2025

Worth the Effort? An Examination on the Effect of Higher Diligence Calculations of the Sound Shell Model

Fazlollah Hajkarim, Graham White, Yang Xiao

The gravitational wave spectrum arising from using the full velocity profile is well known to differ qualitatively from analytic fits to a broken power law. Former studies have sho…

astro-ph.CO2025

Oscillations and parity violation in gravitational wave background from extra tensor modes

Jaume Garriga, Mohammad Ali Gorji, Fazlollah Hajkarim +1

Spectator fields which provide additional tensor degrees of freedom, on top of the standard metric tensor perturbations, can produce significant amounts of gravitational waves (GWs…

hep-ph2025

Supernova-Boosted Dark Matter at Large-Volume Neutrino Detectors

Badal Bhalla, Fazlollah Hajkarim, Doojin Kim +1

Core-collapse supernovae, among the universe's most energetic events, offer a novel window into the dark sector by potentially producing a flux of boosted dark matter (BDM). We exp…

astro-ph.CO2025

Primordial Gravitational Waves from Phase Transitions during Reheating

Amitayus Banik, Nicolás Bernal, Fazlollah Hajkarim

We study primordial gravitational waves (GWs) generated from first-order phase transitions (PTs) during cosmic reheating. Using a minimal particle physics model, and a general para…

hep-ph2025

QUPITER -- Space Quantum Sensors for Jovian-Bound Dark Matter

Yu-Dai Tsai, Fazlollah Hajkarim

We propose utilizing space quantum sensors to detect ultralight dark matter (ULDM) bound to planetary bodies, focusing on Jupiter as the heaviest planet in the solar system. Levera…