Large fluctuations in non-equilibrium stochastic systems
Clustering, pattern formation and phase separation in granular flows
Phase transition kinetics
Ostwald ripening
Self-similarity and dynamic scaling in physics
Fluid dynamics and plasma theory
Nonlinear oscillations and waves, chaos
Our main research area is non-equilibrium statistical mechanics. We mostly study atypically large fluctuations in different non-equilibrium
stochastic systems. Rare large fluctuations are important in a large variety of situations: from a sudden extinction event in a
long-lived population of animals to a rare large peak in the height of a growing surface, and to the unusual trajectory of the
first among myriads of sperm cells, competing with each other for reaching the oocyte. One group of projects deals with the development
and implementation of a novel and efficient description of a whole class of stochastic processes with the help of an approximation method
akin to geometrical optics. The work involves a combination of analytical methods of theoretical physics and applied mathematics and numerical
simulations.
We have recently determined, by the Inverse Scattering Method, the full statistics
of nonstationary heat or mass transfer in some lattice gas models
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4
Suppose that a gas of interacting diffusing particles is trapped inside a cavity with a small hole. What is the average exit time of the first particle from the cavity? Look
here .
Why so many sperm cells? This question motivated this
paper .
Did you know that Brownian motion (and fractional Brownian motion) can sometimes be described by geometrical optics? Look at these papers
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,
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How long will it take for an isolated population (of bacteria, plants, animals or even people) to go extinct? Here are
some of our papers -
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,
2
,
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,
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,
5
, a non-technical review - 6
, and a more comprehensive review - 7
on this kind of problems.
Is there anything in common between a bunch of marbles and an expanding universe? Take a look at
one of our papers on clustering in a freely cooling granular gas.
One fascinating granular phenomenon that we worked
on is granular levitation , when a heavy close-packed
granular cluster is supported from below by a dilute granular gas. Here
is our paper on the
theory and simulations of this system.
Here is our paper on theory of nonequilibrium Ostwald ripening
of granular clusters in electrostatically-driven metallic powders.
Fractal coarsening is a shape relaxation of
fractal objects by surface tension or another "fractality spoiler". Enjoy a small animation, or a larger-scale movie of
the diffusion-controlled coarsening of a DLA cluster, as seen in
numerical simulations. Here is our pioneering work on this
subject. Why do not this and other related systems show simple dynamic scaling behaviors?
See this paper.
I also worked in plasma physics. Here is a review I wrote on nonlinear dynamics
of thermal instability in plasmas that are cooled by their own radiation.
In 2012 I was elected a Fellow of the American Physical Society. Here is the
citation. In 2021 I left the APS.
embraced a broad variety of subjects in nonlinear, non-equilirium and statistical physics. Among them was the discovery in 1979
of chaos in highly-excited
(Rydberg) atoms driven by an oscillating electric field. I made this discovery, together with E.A. Oks and P.V. Sasorov, shortly after defending my Ph.D. thesis.
Here is our 1979 paper. This was one of the pioneering works defining the field of quantum chaos.
When I was a student,
two great physicists, Lev Landau and Richard Feynman, were my heroes. Here are
portraits of Lev Landau
and Richard Feynman, painted by Nataly Meerson. Here is the online
gallery of Nataly. Nataly also painted my portrait
that is displayed on this webpage.