Sarunas Verner

SarunasVerner

Theoretical physicist, KICP Fellow at the University of Chicago

I am a theoretical cosmologist and particle physicist. My research focuses on inflation and reheating. In particular, I study how dark matter, axions, and other new particles were produced in the early universe, including in phase transitions and black hole evaporation. I test these models with measurements of the cosmic microwave background and gravitational waves, as well as other astrophysical data. I also use machine learning to study the structure of physical theories.

Explore research CV and contact
Sarunas Verner, outdoors in front of a stone building and greenery

The inflaton rolls down a Starobinsky-type plateau. Each e-fold stretches space by a factor of e, and 60 of them by e60, about 1026. Behind it is the frozen imprint of quantum fluctuations, computed from the exact de Sitter mode functions.

Research areas

I study models of physics beyond the Standard Model and their consequences in the early universe, with the goal of finding observations that can test them.

Selected work

The full record has 49 papers.

  • Early universe

    Gravitational portals in the early Universe

    S. Cléry, Y. Mambrini, K. A. Olive and S. Verner

    Physical Review D 105, 075005 (2022), arXiv:2112.15214

    We show that graviton exchange alone produces dark matter and radiation during reheating, and derive a lower bound of about 1012 GeV on the maximum temperature.

  • Early universe

    Axion kinetic misalignment and parametric resonance from inflation

    R. T. Co, L. J. Hall, K. Harigaya, K. A. Olive and S. Verner

    JCAP 08, 036 (2020), arXiv:2004.00629

    We show that kinetic misalignment and parametric resonance allow axion dark matter with decay constants well below 1011 GeV when inflation sets a large initial value of the Peccei–Quinn field.

  • Particle physics

    The electroweak sphaleron revisited, I and II

    K. T. Matchev and S. Verner

    Physical Review D 112, 113009 and 113010 (2025), arXiv:2505.05607 and 2505.05608

    We revisit the static electroweak sphaleron and its unstable mode, and then study its nonlinear decay using a public numerical code.

  • Gravitational waves & probes

    New method for the astrometric direct detection of ultralight dark matter

    J. A. Dror and S. Verner

    Physical Review Letters 134, 111003 (2025), arXiv:2406.03526

    We propose to search for ultralight dark matter using the apparent positions of distant sources, such as quasars.

  • Machine learning

    Deep learning symmetries and their Lie groups, algebras, and subalgebras from first principles

    R. T. Forestano, K. T. Matchev, K. Matcheva, A. Roman, E. B. Unlu and S. Verner

    Machine Learning: Science and Technology 4, 025027 (2023), arXiv:2301.05638

    We develop a deep learning method that discovers continuous symmetries and their Lie algebra structure directly from labeled data.

All publications

Calendar

All talks

Upcoming

  1. Thermal Damping of a Spectator Scalar

    Paris-Saclay Astroparticle Symposium

    Workshop talk

  2. Reheating after Inflation

    National Autonomous University of Mexico (UNAM)

    Colloquium

  3. Reheating after Inflation

    University of Chicago

    KICP Chalk Talk

  4. Multimessenger Probes of New Scales in Physics

    Aspen Center for Physics

    Workshop presentation

  5. University of Minnesota

    FTPI Seminar

  6. University of Alabama

    HEP Seminar

About

In 2025 I joined the Kavli Institute for Cosmological Physics at the University of Chicago as a KICP Fellow. Before that, I spent three years as a postdoc at the University of Florida, and I did my Ph.D. with Keith Olive at the University of Minnesota.

More about me

Let’s talk physics

I welcome conversations about early universe cosmology, particle physics, observational probes, and machine learning.

verner@uchicago.edu