On 6 June, a seminar dedicated to the memory of Doctor of Physics and Mathematics, Professor Nikolai Plakida (1937—2022) took place at the Laboratory of Theoretical Physics of the Joint Institute for Nuclear Research. The event was timed to the 87th anniversary of the birth of the Honorary JINR Employee, Honoured Scientist of the Russian Federation.

Chief Researcher of the Scientific and Experimental Department of Neutron Investigations of Condensed Matter at the Laboratory of Neutron Physics Victor Aksenov opened the seminar. He outlined the main periods of the outstanding researcher’s scientific biography: from his student years to the last years of his life. One of the most significant achievements in the career of Nikolai Plakida was the development of the theory of strongly anharmonic crystals. Moreover, he proposed the internationally recognised microscopic theory of high-temperature superconductivity (HTSC). His fundamental monograph “High-temperature cuprate superconductors” (Springer, 2010) is a reference book for modern researchers. In addition, in the late 1960s, as a theorist, he took an active part in the development of the scientific program of the IBR-2 Reactor.

“I have never met such a person as Nikolai Plakida. He had an extraordinary trait that set him apart: he was always eager to talk about things he knew. One’s desire to share knowledge is the quality of a truly outstanding scientist and teacher, whose lasting impact will remain in the hearts and minds of everyone who knew him,” Victor Aksenov recalls.

Leading Researcher at BLTP JINR Sector of Solid State Theory Victor Yushankhai spoke about his memories and the experience of many years of cooperation with Nikolai Plakida. It was under the leadership of Nikolai Plakida that Victor Yushanhkai began to study the subject of HTSC. In his speech, he described in detail how research into high-temperature superconductors had developed.

In the second part of the seminar, FNLP JINR Chief Researcher Anatoly Balagurov presented a talk “Crystals, alloys, and diffraction: the joint work of theorists and experimentalists”. Head of the Department of Electrochemistry of the Faculty of Chemistry of Moscow State University Evgeniy Antipov spoke about the problems and prospects of metal-ion batteries. At the end of the event, Head of the Laboratory of Quantum Mechanical Systems of the RAS Institute of Mathematical Problems of Biology Victor Lakhno spoke about the role of Nikolai Plakida in the development of the polaron theory.

The seminar in memory of Nikolai Plakida was a special, truly important event for the Institute, honouring the memory of the outstanding scientist. At the same time, the event establishes a connection between past, present, and future of science, passing on the valuable experience and legacy of Nikolai Plakida to the younger generation of scientists.