Maria Mylova receives the 2025 Buchalter Cosmology Prize

January 15, 2026
Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI)

Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI) Project Researcher Maria Mylova has been awarded Second Prize for the 2025 Buchalter Cosmology Prize, it was announced on January 8 at the 247th Meeting of the American Astonomical Society in the US.

The Buchalter Cosmology Prize was established in 2014 by Ari Buchalter, an astrophysicist-turned-entrepreneur who remains keenly interested in cosmology. First, Second and Third Prizes are awarded to new ideas or discoveries that have the potential to produce breakthrough advances in our understanding of the origin, structure, and evolution of the universe beyond current standard cosmological models.

Mylova has been recognized for her paper, “A Minimal Axio-dilaton Dark Sector”, a study that extends Einstein’s theory of gravity to predict the existence of very light scalar fields. She and her colleagues focussed on a minimal axion-dilaton framework that arises naturally in fundamental theories, and studied whether it could simultaneously explain both dark matter and dark energy.

“We showed that it can. The axion behaves as dark matter through coherent oscillations, while the dilaton acts as dynamical dark energy, driving cosmic acceleration,” said Mylova.

She added that a key feature of the model is a leading kinetic interaction between the two fields, implying that dark matter and dark energy are intrinsically linked rather than independent.

“I’m very honoured to receive this recognition. The Buchalter Cosmology Prize highlights work that aims to connect fundamental theory with observational cosmology, which is exactly the motivation behind this project. It is gratifying to see that this direction resonates with the wider community, and I’m pleased that the ideas developed in this paper are being recognised as a meaningful contribution to our understanding of the dark sector of the Universe,” said Mylova.

Mylova is already working with collaborators on the next steps of her paper, developing the model into a full observational test to identify clear, testable observational signatures in the cosmic microwave background and large-scale structure.

fig — (Top left and right) The background energy densities vs scale factor a for a strongly coupled axion-dilaton model (top left: absolute, top right: fractional). The Universe transitions from radiation (red) to matter (axion DM in blue, baryons in green), then to dilaton dark energy (orange) today. A distinctive feature is a pre-acceleration bump in the dilaton density around a∼10−1, which briefly boosts the expansion rate and can imprint on structure growth and CMB/LSS power spectra. (Bottom right) The pre-acceleration bump in the dilaton density causes all particle masses to oscillate as the Universe evolves. (Bottom left) The deviation in "power" that we see when we look out on the sky in these models, showing what angular scales telescopes should look at if they want to detect something. (Smith et al.)

Related links
AAS Names Recipients of 2025 Awards & Prizes (American Astronomical Society)
A Minimal Axio-dilaton Dark Sector (arXiv)