On 13–15 September 2026, St. Kliment Ohridski Sofia University (Bulgaria) hosted the Meeting on Theoretical and Mathematical Physics dedicated to the 70th JINR anniversary. The event brought together researchers from Bulgaria and Dubna to discuss topical issues of modern fundamental physics.
Scientists from Sofia University, the Institute of Mechanics of the Bulgarian Academy of Sciences, the BAS Institute for Nuclear Research and Nuclear Energy, the American University in Bulgaria, the BAS Institute of Mathematics and Informatics, and the Bogoliubov Laboratory of Theoretical Physics participated in the event.
BLTP JINR Chief Researcher Alexey Isaev represented the Joint Institute for Nuclear Research. He discussed Vogel’s universality in Lie groups and presented a new mathematical approach based on studies of the spectrum of polarised Casimir operators. These results are important for calculating colour factors of Feynman diagrams in non-abelian gauge theories. Sofia University Professor, member of the JINR Scientific Council Radoslav Rashkov gave a talk on a cohomological approach to entanglement entropy.
The programme focused on a wide range of theoretical issues, including dynamical systems, holography, quantum field theory, modified gravity, black hole physics, and symmetry theory.
The meeting advanced the long-term scientific cooperation between JINR theorists and their colleagues from Bulgarian research centres.
