The Directorate of the Joint Institute for Nuclear Research (JINR, Dubna) deeply regrets to announce that Academician Alexei Norairovich Sissakian, the Director of JINR, a member of the Presidium of the Russian Academy of Sciences, a distinguished theoretical physicist and organizer of scientific research based on broad international cooperation, passed away on 1 May 2010 in his 66th year of life.

 

Alexei Norairovich Sissakian was born on 14 October 1944 in Moscow. In 1968 he graduated from the Physics Faculty of the M. Lomonosov Moscow State University and started work at the JINR Laboratory of Theoretical Physics under the guidance of Academician N.N. Bogoliubov.

 

The main scientific activities of A.N. Sissakian concerned elementary particle physics, approximation methods and equations of quantum field theory, the quantization problem of systems with nontrivial geometry, symmetry and topology, and the physics of strong interactions at high temperatures and densities.

 

In quantum field theory A.N. Sissakian with co-authors were the first to propose and develop the straight-line path approximation –– an effective method of continual integration, which has found wide application in theoretical physics. A.N. Sissakian and colleagues offered a new description of processes with large momentum transfers within the three-dimensional formalism of quantum field theory and developed a multi-component approach in the theory of multiple particle production. Based on this approach, several new effects were predicted and later were confirmed in experiments at the largest particle accelerators.

 

In the field of mathematical physics, under the guidance of A.N. Sissakian, a series of seminal investigations was carried out on classical and quantum superintegrable systems in the constant curvature space, as well as on the generation of topologically nontrivial objects in models with oscillatory interaction and in supersymmetric one-dimensional quantum mechanics. In recent years, A.N. Sissakian and co-workers dealt with further development of the method of contraction of Lie algebras applicable for theoretical physics problems.

 

Of wide recognition were the studies conducted by the research group of Academician A.N. Sissakian on one of the most topical problems of particle physics –– the development and application of nonperturbative methods in quantum field theory and the development of new approaches to very high multiplicity processes. Under the leadership of A.N. Sissakian, novel and promising investigations aimed at searching for processes of the formation of a mixed quark-hadron phase of nuclear matter in heavy-ion collisions were carried out. He initiated and headed the largest project of JINR towards the construction of a heavy-ion collider, NICA, to study phase transitions and critical phenomena in nuclear matter.

 

A.N. Sissakian always combined his active research work with pedagogical and science-organization activities. He supervised 15 theses, headed chairs at Moscow Institute of Physics and Technology and Moscow Engineering Physics Institute, was a professor at the M. Lomonosov Moscow State University, the vice-president of the International University “Dubna” and the head of its Theoretical Physics Chair, he also led the scientific seminar “Symmetries and Integrable Systems” at JINR.

 

Academician A.N. Sissakian was the editor-in-chief of the journal “Physics of Particles and Nuclei, Letters”, a deputy editor-in-chief of the journal “Physics Particles and Nuclei”, a member of the editorial boards of several scientific publications, a member of specialized scientific councils and programme committees of international conferences and symposia, and was the organizer of major international conferences and schools on particle physics.

 

As Vice-Director during 1989–2005 and Director of JINR since 2006, Academician A.N. Sissakian made invaluable contributions towards maintaining and enhancing the potential of JINR, determining its future scientific prospects, improving its research and production capacity, renovating the Institute as an open international nuclear physics laboratory, promoting broad cooperation with national and international research and educational centers, and towards training qualified scientific personnel.

 

A.N. Sissakian was elected a corresponding member of the Russian Academy of Sciences in 2006, and in 2008 – a full member of the Academy and a member of its Presidium.

 

Academician A.N. Sissakian actively participated in the establishment of science cities as President of the Union of Russian Science Cities. He was also first deputy chairman of the Russian Pugwash Committee under the Presidium of the Russian Academy of Sciences.

 

Academician A.N. Sissakian was awarded ten Russian and foreign orders and medals, including the Orders of Honor and Friendship (Russian Federation), was a laureate of the Lenin Komsomol Prize in Science and Technology (1973) and a recipient of the Prize of the Governor of the Moscow Region (2007), was a foreign member of the National Academy of Sciences of Armenia, an honorary doctor of many foreign universities, and a member of several academies and scientific societies.

 

Since school age his favorite hobby had been poetry. Alexei Norairovich Sissakian was the author of several collections of fine poems.

 

Alexei Norairovich was always distinguished by his dedication to science, by a wonderful combination of great will power with kindness and sympathy to his relatives, friends, colleagues, to all people.

 

The fond memory of Alexei Norairovich Sissakian will remain forever in our hearts.