140 citations · 1k across the 22 of their papers we have counts for
24 papers
Big Bang For Your Helium Buck
Marilena Loverde, Murali M. Saravanan, Zachary J. Weiner
We study the implications of a recent measurement of the primordial helium fraction from the Large Binocular Telescope for cosmological inference from the cosmic microwave backgrou…
High-redshift physics from the acoustic scale
Zachary J. Weiner
We present a simplified and general description of the high-redshift information in acoustic scale measurements from the cosmic microwave background and large-scale structure. The…
Dark forces suppress structure growth
Marco Costa, Cyril Creque-Sarbinowski, Olivier Simon +1
No experimental test precludes the possibility that the dark matter experiences forces beyond general relativity---in fact, a variety of cosmic microwave background observations su…
Abundance and properties of dark radiation from the cosmic microwave background
Murali M. Saravanan, Thejs Brinckmann, Marilena Loverde +1
We study the cosmological signatures of new light relics that are collisionless like standard neutrinos or are strongly interacting. We provide a simple and succinct rephrasing of…
Searching for coupled, hyperlight scalars across cosmic history
Masha Baryakhtar, Olivier Simon, Zachary J. Weiner
Cosmological scalar fields coupled to the Standard Model drive temporal variations in the fundamental constants that grow with redshift, positioning the early Universe as a powerfu…
Experimental targets for dark photon dark matter
David Cyncynates, Zachary J. Weiner
Ultralight dark photon dark matter features distinctive cosmological and astrophysical signatures and is also supported by a burgeoning direct-detection program searching for its k…
Massive neutrinos and cosmic composition
Marilena Loverde, Zachary J. Weiner
Cosmological data probe massive neutrinos via their effects on the geometry of the Universe and the growth of structure, both of which are degenerate with the late-time expansion h…
Cosmology with varying fundamental constants from hyperlight, coupled scalars
Masha Baryakhtar, Olivier Simon, Zachary J. Weiner
The fundamental constants at recombination can differ from their present-day values due to degeneracies in cosmological parameters, raising the possibility of yet-undiscovered phys…
Gauge preheating with full general relativity
Peter Adshead, John T. Giblin, Ryn Grutkoski +1
We study gauge preheating following pseudoscalar-driven inflation in full general relativity. We implement the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) scheme to solve the full no…
Detectable and defect-free dark photon dark matter
David Cyncynates, Zachary J. Weiner
Ultralight dark photons are compelling dark matter candidates, but their allowed kinetic mixing with the Standard Model photon is severely constrained by requiring that the dark ph…
Dark photon dark matter from an oscillating dilaton
Peter Adshead, Kaloian D. Lozanov, Zachary J. Weiner
We present a mechanism for generating ultralight dark photon dark matter in the early Universe via a dilatonlike scalar field coupled to the dark photon's kinetic term. Energy is i…
Probing neutrino interactions and dark radiation with gravitational waves
Marilena Loverde, Zachary J. Weiner
After their generation, cosmological backgrounds of gravitational waves propagate nearly freely but for the expansion of the Universe and the anisotropic stress of free-streaming p…
Nonperturbative structure in coupled axion sectors and implications for direct detection
David Cyncynates, Olivier Simon, Jedidiah O. Thompson +1
Pairs of misalignment-produced axions with nearby masses can experience a nonlinear resonance that leads to enhanced direct and astrophysical signatures of axion dark matter. In mu…
The Physics of Light Relics
Cora Dvorkin, Joel Meyers, Peter Adshead +19
Many well-motivated extensions of the Standard Model predict the existence of new light species that may have been produced in the early universe. Prominent examples include axions…
Non-Gaussianity and the induced gravitational wave background
Peter Adshead, Kaloian D. Lozanov, Zachary J. Weiner
Scalar metric fluctuations generically source a spectrum of gravitational waves at second order in perturbation theory, poising gravitational wave experiments as potentially powerf…
Time-dependent heterogeneity leads to transient suppression of the COVID-19 epidemic, not herd immunity
Alexei V. Tkachenko, Sergei Maslov, Ahmed Elbanna +3
Epidemics generally spread through a succession of waves that reflect factors on multiple timescales. On short timescales, super-spreading events lead to burstiness and overdispers…
Constraining early dark energy with gravitational waves before recombination
Zachary J. Weiner, Peter Adshead, John T. Giblin
We show that the nonperturbative decay of ultralight scalars into Abelian gauge bosons, recently proposed as a possible solution to the Hubble tension, produces a stochastic backgr…
Modeling COVID-19 dynamics in Illinois under non-pharmaceutical interventions
George N. Wong, Zachary J. Weiner, Alexei V. Tkachenko +3
We present modeling of the COVID-19 epidemic in Illinois, USA, capturing the implementation of a Stay-at-Home order and scenarios for its eventual release. We use a non-Markovian a…
Stochastic evolution of scalar fields with continuous symmetries during inflation
Peter Adshead, Lauren Pearce, Jessie Shelton +1
During inflation, scalar fields with masses less than the Hubble scale acquire vacuum expectation values (vevs) via stochastic processes driven by quantum fluctuations. For nearly…
Constraining axion inflation with gravitational waves across 29 decades in frequency
Peter Adshead, John T. Giblin, Mauro Pieroni +1
We demonstrate that gravitational waves generated by efficient gauge preheating after axion inflation generically contribute significantly to the effective number of relativistic d…
Constraining axion inflation with gravitational waves from preheating
Peter Adshead, John T. Giblin, Mauro Pieroni +1
We study gravitational wave production from gauge preheating in a variety of inflationary models, detailing its dependence on both the energy scale and the shape of the potential.…
Gravitational waves from gauge preheating
Peter Adshead, John T. Giblin, Zachary J. Weiner
We study gravitational wave production during Abelian gauge-field preheating following inflation. We consider both scalar and pseudoscalar inflaton models coupled directly to Abeli…
Gravitational waves from asymmetric oscillon dynamics?
Mustafa A. Amin, Jonathan Braden, Edmund J. Copeland +4
It has been recently suggested that oscillons produced in the early universe from certain asymmetric potentials continue to emit gravitational waves for a number of -folds of ex…
Non-Abelian gauge preheating
Peter Adshead, John T. Giblin, Zachary J. Weiner
We study preheating in models where a scalar inflaton is directly coupled to a non-Abelian gauge field. In particular, we examine inflation with a conformal, dila…