Question: What is the type of particle of the concept that was proposed by the Soviet physicist who also discovered the theory of superfluidity?

Context paragraphs:
Supersymmetry: In particle physics, supersymmetry (SUSY) is a proposed type of spacetime symmetry that relates two basic classes of elementary particles: bosons, which have an integer-valued spin, and fermions, which have a half-integer spin.  Supersymmetry is a possible candidate for undiscovered particle physics, and seen as an elegant solution to many current problems in particle physics if confirmed correct, which could resolve various areas where current theories are believed to be incomplete.  A supersymmetrical extension to the Standard Model would resolve major hierarchy problems within gauge theory, by guaranteeing that quadratic divergences of all orders will cancel out in perturbation theory.

Nikolay Dikansky: Nikolay Dikansky (Russian: Николай Сергеевич Диканский ; born 30 July 1941, Dymytrov, Ukraine) — is a Russian/Soviet physicist, a scientist in the fields of accelerator physics and particle accelerators, the head of the laboratory in Budker Institute of Nuclear Physics, since 2011 academician of Russian Academy of Sciences, the chancellor of Novosibirsk State University (20 November 1997 – 30 July 2007).

Lev Landau: Lev Davidovich Landau (Russian: Лев Дави́дович Ланда́у ; ] ; January 22 [O.S. January 9] 1908 1 April 1968) was a Soviet physicist who made fundamental contributions to many areas of theoretical physics.  His accomplishments include the independent co-discovery of the density matrix method in quantum mechanics (alongside John von Neumann), the quantum mechanical theory of diamagnetism, the theory of superfluidity, the theory of second-order phase transitions, the Ginzburg–Landau theory of superconductivity, the theory of Fermi liquid, the explanation of Landau damping in plasma physics, the Landau pole in quantum electrodynamics, the two-component theory of neutrinos, and Landau's equations for "S" matrix singularities.  He received the 1962 Nobel Prize in Physics for his development of a mathematical theory of superfluidity that accounts for the properties of liquid helium II at a temperature below ( ).

Leonard Parker: Leonard Emanuel Parker (born Leonard Pearlman in 1938 in Brooklyn, New York) is a Distinguished Professor Emeritus of Physics and a former Director of the Center for Gravitation and Cosmology at the University of Wisconsin–Milwaukee.  During the late 1960s, Parker established a new area of physics - quantum field theory in curved spacetime.  Specifically, by applying the technique of Bogoliubov transformations to quantum field theory with a changing gravitational field, he discovered the physical mechanism now known as gravitational particle production.  His work inspired research by hundreds of physicists and has been cited in more than 2,000 research papers; it was credited in the memoirs of Soviet physicist Andrei Sakharov and helped Stephen Hawking discover the creation of particles by black holes.

Richard Feynman: Richard Phillips Feynman ( ; May 11, 1918 – February 15, 1988) was an American theoretical physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics for which he proposed the parton model.  For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Shin'ichirō Tomonaga, received the Nobel Prize in Physics in 1965.

Alexei Fridman: Alexey Maksimovich Fridman was a Soviet physicist specializing in astrophysics, physics of gravitating systems and plasma physics.  He discovered new types of instabilities in gravitating media, created the theory of planetary rings and predicted the existence of small Uranus satellites that were later discovered.  He also developed hydrodynamic theory of the spiral structure in galaxies.  Fridman worked at the Institute of Astronomy of the Russian Academy of Sciences, INASAN , and was professor of Moscow Institute of Physics and Technology and Moscow State University.

Aleksandr Andronov: Aleksandr Aleksandrovich Andronov (Russian: Алекса́ндр Алекса́ндрович Андро́нов ; April 11 [O.S. March 29] 1901 , Moscow – October 31, 1952, Gorky) was a Soviet physicist and member of the Soviet Academy of Sciences (1946).  He worked extensively on the theory of stability of dynamical systems, introducing (together with Lev Pontryagin) the notion of structural stability.  In that context, he also contributed to the mathematical theory of self-oscillation (a term that he coined) by establishing a link between the generation of oscillations and the theory of Lyapunov stability.  He developed the comprehensive theory of self-oscillations by linking it with the qualitative theory of differential equations, topology, and with the general theory of stability of motion.  The crater Andronov on the Moon is named after him.

Isaak Pomeranchuk: Isaak Yakovlevich Pomeranchuk (Russian: Исаа́к Я́ковлевич Померанчу́к ; 20 May 1913, Warsaw, Russian Empire – 14 December 1966, Moscow, USSR) was a Soviet physicist, who was the founder and first head of the theory division at ITEP.  The particle pomeron is named in his honour.  For his work, Pomeranchuk was twice awarded the Stalin State Prize (1950,1952).  He was elected a corresponding member of the Academy of Sciences of the USSR in 1953 and full member in 1964.

Polaron: A polaron is a quasiparticle used in condensed matter physics to understand the interactions between electrons and atoms in a solid material.  The polaron concept was first proposed by Lev Landau in 1933 to describe an electron moving in a dielectric crystal where the atoms move from their equilibrium positions to effectively screen the charge of an electron, known as a phonon cloud.  This lowers the electron mobility and increases the electron's effective mass.

Fermi liquid theory: Fermi liquid theory (also known as Landau–Fermi liquid theory) is a theoretical model of interacting fermions that describes the normal state of most metals at sufficiently low temperatures.  The interaction between the particles of the many-body system does not need to be small.  The phenomenological theory of Fermi liquids was introduced by the Soviet physicist Lev Davidovich Landau in 1956, and later developed by Alexei Abrikosov and Isaak Khalatnikov using diagrammatic perturbation theory.  The theory explains why some of the properties of an interacting fermion system are very similar to those of the Fermi gas (i.e. non-interacting fermions), and why other properties differ.

Supporting paragraphs: Polaron Lev Landau
Answer: quasiparticle