Lev Nikolaevich Lipatov, an outstanding theoretical physicist, fellow of
the Russian Academy of Sciences and Director of the Theory Division of
the Petersburg Nuclear Physics
Institute passed away September 4th, 2017, at the age of 77. Lev Lipatov is a world
renowned scientist, one of a small group of the most brilliant minds of
the modern theoretical physics.
He created a scientific school that brought together theorists from
Russia, Germany, United States, Spain,
Israel, Slovakia
and other countries.
It is hard to overestimate Lipatov's contribution to the creation and
development of
Quantum Chromodynamics. For many years he was (and remained up to the very last
moment) the world leader in
the field perturbative QCD theory. The method of summation of the leading
logarithms suggested and
developed in the groundbreaking works by V. N. Gribov and L. N. Lipatov
became the backbone of the
modern theory of hard QCD processes. A self consistent QCD parton model
that followed from the
summation of the leading logarithms predicted logarithmic evolution of the
structure functions with
the transferred momentum. The respective evolution equations are now
known as the DGLAP equations (after Dokshitzer, Gribov, Lipatov, Altarelli, and Parisi).
All his life L. N. Lipatov was deeply involved in the research on the high
energy scattering in QCD.
He (in collaboration with others) obtained the famous BFKL (Balitsky,
Fadin, Kuraev, Lipatov) equation. This equation allows to find the structure of the scattering
amplitude singularities in
the complex angular momentum plane, and therefore, determines the high
energy asymptotic behavior of
the scattering amplitudes. The BFKL theory is nowadays the basic tool for
description of scattering
at high energy accelerators. It is not an exaggeration to say that all
our
understanding of high
energy scattering is based on the works of L. N. Lipatov and his school.
Lev Nikolaevich Lipatov excelled in research of the perturbative Quantum
Field
Theory. He had an
amazing ability to find elegant and mathematically rigorous solutions of
prohibitively difficult
problems. He had suggested and developed an effective method for analysis
of the
asymptotic behavior
of the perturbation theory series in Quantum Field Theory. His works on
this subject
acquired now
the status of the theoretical physics classics. They now form the basis of
our
knowledge about the
behavior of the perturbation theory series and their singularities in the
complex
coupling constant
plane.
In recent years L. N. Lipatov's attention was drawn to the N=4
supersymmetric
Yang-Mills theory. He
used the BFKL approach to show that this remarkable theory is completely
integrable
and (probably)
is even exactly solvable. He also worked a lot on the reggeon theory in
quantum
chromodynamics and
gravity. This project, unfortunately. remained unfinished...
L. N. Lipatov is well known and highly respected by his peers around the
world. His
publications
collected more than 26000 citations what emphasizes wide recognition and
high
appreciation of his
results. Scientific achievements of L. N. Lipatov were acknowledged by
numerous
prizes and awards.
Among his other awards are the 2001 I.Ya. Pomeranchuk prize and the 2015
European
Physical Society
High Energy and Particle Physics Prize.
Besides the research activity L. N. Lipatov was teaching at the Saint
Petersburg
State University,
participated in organizing a number of national and international physics
schools
and conferences,
in particular the annual PNPI wither schools. He was a co-chairman of the
well
known international
conference series on Quantum Chromodynamics and Hadron Structure (HSQCD).
Memory of Lev Nikoleavich will forever live in our hearts.
The funeral will be held on Friday, September 8, in Petersburg Nuclear Physics Institute.
Theory Division faculty and staff.