200 citations · 2.2k across the 48 of their papers we have counts for
24 papers · 1 filter
Non-Minimally Coupled Chain Inflation at High Scales
Miguel Barroso Varela, Orfeu Bertolami, Katherine Freese +1
Chain inflation offers an alternative to standard slow-roll dynamics, with accelerated expansion proceeding through a sequence of rapid quantum tunneling events between metastable…
Phenomenology of Inflaton-Driven Early QCD Confinement and Solution to Axion Isocurvature Problem
Evangelos I. Sfakianakis, Barmak Shams Es Haghi, Katherine Freese
We study the phenomenology of early QCD confinement during inflation, driven by a direct coupling between the inflaton and Standard Model gluons. This coupling dynamically raises t…
Isocurvature-Free QCD Axion Dark Matter from Inflaton-Driven Early QCD: the Necessity of Inflationary Plateaus
Katherine Freese, Evangelos I. Sfakianakis, Barmak Shams Es Haghi
A direct coupling between the inflaton and Standard Model gluons can dynamically raise the QCD confinement scale during inflation, making the axion temporarily heavy and suppressin…
Gravitational Wave Echoes of the First Order Phase Transition in a Kination-Induced Big Bang
Richard Casey, Katherine Freese, Evangelos I. Sfakianakis
Gravitational waves (GWs) produced during first-order phase transitions (FOPTs) in the early universe provide a powerful probe of nonstandard cosmological histories. We study GW pr…
Early Formation of Supermassive Black Holes via Dark Star Gravitational Instability
Katherine Freese, George M. Fuller, Sohan Ghodla +4
We show that dark stars, which are dark-matter-powered stars in the early universe, can grow by accretion to masses in the range $\mathscr{O}\left ({10}^4\right )-\mathscr{O}\left…
Schwinger effect in axion inflation on a lattice
Oksana Iarygina, Evangelos I. Sfakianakis, Axel Brandenburg
We present the first lattice simulations of the nonlinear evolution after axion inflation by self-consistently incorporating currents arising from Schwinger pair production. The ta…