251 citations · 1.9k across the 44 of their papers we have counts for
44 papers
Quadratic Axion Couplings in String Theory
Naman Agarwal, Andrew R. Frey, Ratul Mahanta +1
Axions and axion-like particles are a compelling candidate for physics beyond the standard model. While many axion searches are focused on the linear coupling to photons $θF \tilde…
The -axion and -axiverse of dark QCD
Stephon Alexander, Humberto Gilmer, Tucker Manton +1
Axions and axion-like particles (ALPs) are a prominent dark matter candidate, drawing motivation in part from the axiverse of string theory. Axion-like particles can also arise as…
Early Dark Energy in Type IIB String Theory
Michele Cicoli, Matteo Licheri, Ratul Mahanta +3
Early Dark Energy (EDE) is a promising model to resolve the Hubble Tension, that, informed by Cosmic Microwave Background data, features a generalization of the potential energy us…
Planck Constraints and Gravitational Wave Forecasts for Primordial Black Hole Dark Matter Seeded by Multifield Inflation
Wenzer Qin, Sarah R. Geller, Shyam Balaji +2
We perform a Markov Chain Monte Carlo (MCMC) analysis of a simple yet generic multifield inflation model characterized by two scalar fields coupled to each other and nonminimally c…
A Dark Matter Trigger for Early Dark Energy Coincidence
Meng-Xiang Lin, Evan McDonough, J. Colin Hill +1
Early dark energy (EDE), whose cosmological role is localized in time around the epoch of matter-radiation equality in order to resolve the Hubble tension, introduces a new coincid…
Towards A Direct Detection of the Spin of Dark Matter
Leah Jenks, Konstantinos Koutrolikos, Evan McDonough +2
We investigate the contribution of higher spin particles in the signal of direct detection experiments searching for dark matter. We consider a bosonic or fermionic higher spin dar…
Completely Dark Matter from Rapid-Turn Multifield Inflation
Edward W. Kolb, Andrew J. Long, Evan McDonough +1
We study cosmological gravitational particle production as applied to "rapid-turn" models of inflation involving two scalar fields. We are interested in the production of massive s…
Towards Early Dark Energy in String Theory
Evan McDonough, Marco Scalisi
Early Dark Energy (EDE) is a prominent model to resolve the Hubble tension, which employs a dynamical axion with a periodic potential. In this work, we take first steps towards the…
Ultra-Light Pion and Baryon WIMPzilla Dark Matter
Azadeh Maleknejad, Evan McDonough
We consider a dark confining gauge theory with millicharged Ultra-Light Pions (ULP) and heavy baryons as dark matter candidates. The model simultaneously realizes the ultra-light (…
Primordial Black Holes from Multifield Inflation with Nonminimal Couplings
Sarah R. Geller, Wenzer Qin, Evan McDonough +1
Primordial black holes (PBHs) provide an exciting prospect for accounting for dark matter. In this paper, we consider inflationary models that incorporate realistic features from h…
The Early Dark Sector, the Hubble Tension, and the Swampland
Evan McDonough, Meng-Xiang Lin, J. Colin Hill +2
We consider the interplay of the Early Dark Energy (EDE) model, the Swampland Distance Conjecture (SDC), and cosmological parameter tensions. EDE is a proposed resolution of the Hu…
Cosmic Filament Spin from Dark Matter Vortices
Stephon Alexander, Christian Capanelli, Elisa G. M. Ferreira +1
The recent observational evidence for cosmic filament spin on megaparsec scales (Wang et al, Nature Astronomy 5, 839-845 (2021)) demands an explanation in the physics of dark matte…
Amplification of Primordial Perturbations from the Rise or Fall of the Inflaton
Keisuke Inomata, Evan McDonough, Wayne Hu
The next generation of cosmic microwave background, gravitational wave, and large scale structure, experiments will provide an unprecedented opportunity to probe the primordial pow…
Primordial Black Holes Arise When The Inflaton Falls
Keisuke Inomata, Evan McDonough, Wayne Hu
Primordial Black Holes (PBHs) have entered the forefront of theoretical cosmology, due their potential role in phenomena ranging from gravitational waves, to dark matter, to galaxy…
The Gravitino Swampland Conjecture
Edward W. Kolb, Andrew J. Long, Evan McDonough
We extend the swampland from effective field theories (EFTs) inconsistent with quantum gravity to EFTs inconsistent with quantum supergravity. This enlarges the swampland to includ…
Catastrophic Production of Slow Gravitinos
Edward W. Kolb, Andrew J. Long, Evan McDonough
We study gravitational particle production of the massive spin- Rarita-Schwinger field, and its close relative, the gravitino, in FRW cosmological spacetimes. For masses light…
Higher Spin Dark Matter
Stephon Alexander, Leah Jenks, Evan McDonough
Little is known about dark matter beyond the fact that it does not interact with the standard model or itself, or else does so incredibly weakly. A natural candidate, given the his…
Strongly-Interacting Ultralight Millicharged Particles
Stephon Alexander, Evan McDonough, David N. Spergel
We consider the implications of an ultra-light fermionic dark matter candidate that carries baryon number. This naturally arises if dark matter has a small charge under standard mo…
Nonminimal Couplings and the Forgotten Field of Axion Inflation
Evan McDonough, Alan H. Guth, David I. Kaiser
We study the multifield dynamics of axion models nonminimally coupled to gravity. As usual, we consider a canonical symmetry-breaking model in which the axion is the phase o…
Constraining Early Dark Energy with Large-Scale Structure
Mikhail M. Ivanov, Evan McDonough, J. Colin Hill +4
An axion-like field comprising of the energy density of the universe near matter-radiation equality is a candidate to resolve the Hubble tension; this is the "early dar…
Chiral Symmetry and the Cosmological Constant
Stephon Alexander, Gabriel Herczeg, Jinglong Liu +1
In this work we provide a link between a nearly vanishing cosmological constant and chiral symmetry. This is accomplished with a modification of General Relativity coupled to a top…
The Cosmological Heavy Ion Collider: Fast Thermalization after Cosmic Inflation
Evan McDonough
Heavy-ion colliders have revealed the process of "fast thermalization". This experimental breakthrough has led to new theoretical tools to study the thermalization process at both…
Deep Learning the Morphology of Dark Matter Substructure
Stephon Alexander, Sergei Gleyzer, Evan McDonough +2
Strong gravitational lensing is a promising probe of the substructure of dark matter halos. Deep learning methods have the potential to accurately identify images containing substr…
Higher Spin Supersymmetry at the Cosmological Collider: Sculpting SUSY Rilles in the CMB
Stephon Alexander, S. James Gates, Leah Jenks +2
We study the imprint of higher spin supermultiplets on cosmological correlators, namely the non-Gaussianity of the cosmic microwave background. Supersymmetry is used as a guide to…