Obituary Roberto Nicolsky (1938-2024)

With deep sorrow, we announce the passing of Roberto Nicolsky, an individual whose life was marked by remarkable achievements and contributions in various fields. Entrepreneur, innovator and an influential researcher, Prof. Nicolsky trained generations of physicists and engineers.

Born in Russia in 1938, the son of a Russian father and Brazilian mother, Roberto Nicolsky came to Brazil at the age of 8 and chose to become Brazilian at the age of 18, following his own path. His academic journey was characterized by an unrelenting pursuit of knowledge, obtaining degrees in physics and economics simultaneously, although he did not complete physics. After his graduation in economics, he began his career at Editora Abril, a large Brazilian publishing company, followed by an experience at a foundry in the interior of São Paulo, Brazil, which later resulted in the acquisition of his own foundry.

In 1964, Roberto achieved Bachelor's degree in Physics at the UFRJ (Federal University of Rio de Janeiro). After dedicating himself to working in the financial market, he returned to physics research in 1979, working with weak connections and non-equilibrium in superconductors. His commitment to academic excellence led him to earn a master's degree at USP (University of São Paulo, Brazil). He obtained his MSc. in 1981, covering his line of research until then. Even during this phase, he continued to produce heating elements with tubes of high-nickel alloy content, being the sole producer in Brazil.

He became a professor at UFRJ in 1981 until his retirement in 2010. At UFRJ he continued his basic research focusing on superconducting junctions and exploring the use of time-dependent Bogoliubov–de Gennes equations and Andreev reflection in Superconducting junctions, mainly SNS (Superconductor - Normal Metal - Superconductor) junctions.

At UFRJ he received recognition for self-guidance in his doctoral research on Metallic Josephson Junctions: Theory and Applications. In 1991, Roberto obtained the DSc. in Physics. His thesis had shown that all models at that time (models for superconducting metallic Josephson junctions, or SNS, or weak-links, based on phenomenological time dependent Ginzburg-Landau equations) could not explain the complexity of the current-voltage characteristics of metallic junctions in nonequilibrium, because their behavior is determined by the relationship between the microscopic charge carriers at both sides of the superconductor-normal metal interfaces. His research developed a theory for nonequilibrium metallic superconducting junctions, in a configuration with uniform electric field applied in the normal part, as time-dependent and gauge-invariant Bogoliubov-De Gennes solutions. He was able to form wave packets from the nonequilibrium electron and hole solutions of the time-dependent Bogoliubov–de Gennes equations, and after that to obtain a detailed microscopic picture of quasiparticle acceleration and electron-hole (Andreev) scattering. The characteristic curves of experimentally observed CVC’s in microbridges, SNS sandwiches, and point contacts are than obtained computing the time-averaged current density from those wave packets.

The obtained current-voltage characteristics from his theory were used to define a new criterion for determining the metallic or tunneling character of the intrinsic junctions and used the new low voltage negative differential resistance effect to develop superconductive electronics independent of the Josephson AC effect, and based on the characteristics of the Andreev scattering mechanism.

He also dedicated himself to technological research on the use of superconducting junctions for the generation and detection of electromagnetic radiation (radio waves and microwaves ranges) and his results led to the proposal of new devices with superconductor technology. He obtained two patents: one on a "Harmonic Oscillator Using the Negative Differential Resistance of a Superconducting Microbridge (Or SNS Type Josephson Junction)", obtained in 1995, and the other on a "Heterodyne Mixer Using the Nonlinearity of the Microbridge Current-Voltage Characteristic Curves SNS (Superconductor-Normal Metal-Superconductor)", obtained in 1997.

His dedication to advancing science was evidenced by his organization of the Brazilian Congress of Superconductivity in 1998, where he brought the renowned Nobel laureate in Physics Johannes Georg Bednorz to Brazil.

Roberto Nicolsky followed his ideal to integrate scientific research and technological development in Brazil: He founded the LASUP (Laboratory of Superconductor Applications) in the Polytechnic Institute at UFRJ and started a series of Brazilian Schools of Superconductivity for Physics and Engineering students in Brazil. In LASUP Roberto Nicolsky developed research on Fault Current Limiters, Flywheel Energy Storage Systems, and significantly contributed to the development of the Maglev Cobra, an international benchmark in the field of magnetic levitation transportation. After his retirement in 2010, he devoted himself to PROTEC, an institution advocating innovation for Brazilian entrepreneurs, whose legacy continued to influence even after his passing.

Roberto Nicolsky leaves behind a lasting legacy, not only as an exceptional academic but also as a visionary committed to the scientific and technological progress of Brazil. His impact will be felt for generations, and his absence will be deeply mourned by all those whose lives he touched. May his memory endure as a source of inspiration and motivation for us all. May he rest in peace.