Alexander Patashinski

Alexander Zakharovich Patashinski, an outstanding theoretical physicist, died of heart failure at his home near Seattle on 22 February 2020. He was 83 years old.

Alexander (Sasha to his numerous friends and colleagues, and AZ to his students) was born on 8 August 1936 in Vitebsk, Soviet Union (now Belarus). In 1941, when Nazi Germany attacked the Soviet Union, the Patashinski family was evacuated to Novosibirsk in Siberia. Alexander’s father fought in the Soviet army and was killed in 1944. After graduating from high school in Novosibirsk, in 1954 Alexander was accepted to the Moscow Institute of Physics and Technology. Starting in 1958, he was working on his undergraduate diploma and then on his PhD thesis at the Institute for Physical Problems, founded and then led by Peter Kapitza. Alexander began as an experimentalist but subsequently moved into theoretical physics. He passed the celebrated Landau theoretical minimum and became one of Lev Landau’s last students. In 1961 Alexander moved to Novosibirsk and began working at the Institute of Thermal Physics of Siberian Branch of the USSR Academy of Sciences, headed by S. S. Kutateladze. In 1963 he defended his PhD thesis and started working with Valery Pokrovsky on theory of phase transitions.

By the early 1960s the second-order phase transitions, such as the Curie point in ferromagnetics or the metal–superconductor transition, had been successfully explained by Landau (1937) as spontaneous breaking of the background symmetry. At the same time, it was already demonstrated by Arkady Levanyuk and Vitaly Ginzburg that the mean-field theory is violated in the vicinity of the phase transition due to long-wavelength fluctuations. The critical phenomena in the range of strong fluctuations was a most challenging problem of the theory of condensed matter at that time.

In 1964 Alexander and Pokrovsky formulated the hypothesis of self-similarity of fluctuations at different scales and derived the relationships between various scaling exponents. Their subsequent 1966 paper unified all the known scaling relationships and proposed several new ones. This research, summarized in the 1979 book Fluctuation Theory of Phase Transitions, was a groundbreaking step in the development of modern theory of critical phenomena and renormalization group theory. The Patashinski–Pokrovsky fluctuation theory of phase transitions was developed independently and nearly simultaneously with the scaling and renormalization work of Leo Kadanoff, Benjamin Widom, and Michael Fisher in the US. When Kenneth Wilson was awarded the Nobel Prize in Physics in 1982, the papers by Alexander and Pokrovsky were explicitly recognized in the press release of the Swedish Royal Academy of Sciences and in Wilson’s talk as the predecessor of Wilson’s renormalization group theory.

In the 1970s and 1980s, Alexander continued his work in Novosibirsk as a senior scientist at the Budker Institute of Nuclear Physics and as a professor at Novosibirsk State University. Together with Boris Shumilo, he developed a theory of nucleation in a metastable state near a critical point. With Anton Mitus, he proposed novel insights into the structure of liquids and solids. He also worked on many engineering problems, applying fundamental physics to real-life industrial challenges.

In 1992 Alexander moved to the US and became a faculty member at Northwestern University in Evanston, Illinois. At Northwestern, he studied the structure of liquids and solids, expanding also into more complex states of matter like liquid crystals and glasses. Continuing his collaboration with Mitus, he utilized computer simulations to complement his analytical theories and to quantify the degree of structural order, disorder, and phase separation in various systems. His research also resulted in a number of industrial applications, from electrically conductive composites based on the idea of double percolation (with Kalle Levon and Alla Margolina) to the design of nanocomposite detectors of toxic cations (with Bartosz Grzybowski and others). Beginning in the late 1990s, Alexander became a frequent consultant and collaborator to researchers at The Dow Chemical Company in Midland, Michigan. His insights were instrumental in the development of a new fundamental structure-property model for polyurethanes, mechanics of glassy polymers, and many other problems.

Sasha was an extremely talented theorist. Most of all, his talent revealed itself in solutions of very difficult problems of mathematical physics in which the statement of problem was firmly established, but due to mathematical difficulties they remained unsolved for a long time. In those cases, Sasha was irreplaceable, with his strong and precise intuition and mighty analytical technique. AZ was also a role model to younger scientists in the universality of his scientific knowledge and his vision and creativity in resolving scientific, engineering, and life puzzles and challenges. Sasha’s versatile talents were not limited by just physics: He was a singer, a jazzman, a polyglot, and a storyteller who shared his recollections about his youth in postwar Russia, his work with Landau, and even his career as an amateur boxer.

Alexander’s awards include the Landau Prize of the USSR Academy of Sciences (1983) and election as an American Physical Society Fellow (2011). For him, however, the most important reward was science itself as well as friendship and interaction. As a mentor and friend to many fellow physicists, he will be fondly remembered and deeply missed.

Written by Valeriy Ginzburg, Richard Bausch, Alexander Chaplik, Michael Chertkov, Heiner Mueller-Krumbhaar, Alexander Migdal, Alexander Polyakov, Valery Pokrovsky, Arkady Vainshtein, and Vladimir Zakharov