Yuri A. Simonov

We are deeply saddened to announce the passing of Yuri A. Simonov, a distinguished theoretical physicist whose contributions left a lasting mark on elementary particle theory, theoretical nuclear physics, quantum chromodynamics (QCD), and the physics of strong interactions. His legacy encompasses profound scientific achievements, exceptional mentorship, and an unwavering commitment to the advancement of knowledge.

Yuri Antonovich Simonov began his scientific career at the Institute of Theoretical and Experimental Physics (ITEP) in Moscow—now part of the Kurchatov Institute National Research Center—after graduating from the Moscow Engineering Physics Institute in 1958. He earned his PhD in 1964 and the degree of Doctor of Physical and Mathematical Sciences in 1971. He was a student of I. Ya. Pomeranchuk, K. A. Ter-Martirosyan was his PhD adviser, and he worked under the guidance of A. I. Alikhanov, the founding director of ITEP.

In the early stage of his career (1960–64), Simonov obtained fundamental results in Regge theory and the theory of dispersion relations. Between 1965 and 1972, he developed the hyperspherical function method (K-harmonics) for multinucleon systems, which gained international recognition and became a powerful tool for the study of few-body systems in nuclear, atomic, high-energy, and condensed-matter physics. From 1978 to 1981, he proposed the composite quark bag model for multiquark states, providing a foundation for calculations of hadron–hadron interactions at low and intermediate energies.

Beginning in 1983, Simonov focused on nonperturbative QCD. He introduced the method of QCD field correlators, enabling systematic studies of confinement and chiral effects in the QCD vacuum. Within this framework, he derived representations for quark and gluon Green’s functions and calculated mass spectra of mesons, baryons, hybrids, glueballs, and multiquark states using a minimal set of fundamental parameters. Among his most significant achievements was establishing a deep connection between confinement and spontaneous chiral symmetry breaking, as well as predicting the freezing of the strong coupling constant at low Euclidean momenta.

In 1991, Simonov calculated the transition temperature to the quark–gluon plasma, laying the foundation for a new theoretical description of a strongly interacting plasma containing bound quark and gluon states. In subsequent years, he remained actively engaged in a wide range of research topics, working closely with young collaborators. Under his leadership and with his direct participation, a new theory of four-quark resonances was developed.

The exceptional scientific achievements of Simonov were recognized by numerous prestigious awards, including the International Humboldt Prize, the MAIK “Science” Competition Prize, the I. Ya. Pomeranchuk International Prize, and, in 2024, the I. V. Kurchatov Medal. He devoted great attention to teaching and mentoring young scientists, lecturing advanced physics courses at the Moscow Institute of Physics and Technology, and supervising many successful PhD students. He remained deeply supportive of his students’ research and career development long after they had completed their degrees.

We remember Yuri Antonovich Simonov as an extraordinary scientist, a generous and inspiring mentor, and a principled, deeply caring individual whose wisdom, kindness, and support were valued by students and colleagues alike. The memory of Yuri Antonovich Simonov—a great scientist, teacher, and human being—will forever remain in our hearts.

Alla Badalian, Ben Bakker, Günter Dosch, Victor Egorychev, Adriano Di Giacomo, Alexey Nefediev, Boris Kerbikov, Yulia Kalashnikova, Ilya Narodetsky, and Vladimir Shevchenko also contributed to this obituary.

Submissions are lightly edited for grammar and style. Click here for guidelines on submitting an obituary. If you are a copyright holder who thinks that an obituary violates your copyright, please contact us .