Колоколов Игорь Валентинович
Базовая кафедра теоретической физики Института теоретической физики им. Л.Д. Ландау РАН
Профессиональные интересы
Должности
- Заведующий кафедрой — Базовая кафедра теоретической физики Института теоретической физики им. Л.Д. Ландау РАН
- Профессор — Базовая кафедра теоретической физики Института теоретической физики им. Л.Д. Ландау РАН
Био
- · Начал работать в НИУ ВШЭ в 2016 году.
- · Научно-педагогический стаж: 27 лет.
Образование
- 2025 · Член-корреспондент РАН
- 2010 · Ученое звание: Доцент
- 1998 · Доктор физико-математических наук
- 1983 · Специалитет: Новосибирский государственный университет им. Ленинского комсомола, специальность «Физика», квалификация «Физик»
Опыт работы
- · 1983: В году закончил Новосибирский государственный университет, получил диплом по специальности «физика». В
- · 1990: году защитил кандидатскую диссертацию по специальности «теоретическая физика», которая была посвящена развитию функциональных методов в статистической физике квантовых магнетиков и использованию магнитных сред для поиска псевдоскaлярных дальнодействий (частиц типа аксионов и арионов). Работал в ИЯФ им. Будкера старшим, и затем, ведущим научным сотрудником. В
- · 1998: году защитил докторскую диссертацию по специальности "теоретическая физика" на основе решенных с его участием задач статистической гидродинамики. С
- · 2003: года работает в Институте Теоретической Физики им. Л.Д.Ландау ведущим научным сотрудником, тогда же был избран на должность заместителя директора ИТФ им. Л.Д.Ландау
- · Курсы:
- · Математические методы физики, Физическая Кинетика, Физика Сплошных Сред, Избранные Главы Статистической Физики, Магнетизм -
- · ФФ НГУ, ФОПФ МФТИ,
- · Физическая Кинетика - Национальный Исследовательский Университет Высшая Школа Экономики
Награды и поощрения
- · Благодарность декана факультета физики НИУ ВШЭ (январь 2023)
- · Надбавка за публикацию в журнале из Списка А (и приравненном к нему научном издании) (2025–2026, 2024–2025, 2023–2024)
- · Надбавка за публикацию в международном рецензируемом научном издании (2022–2023, 2021–2022, 2019–2021, 2017–2019)
Идентификаторы исследователя
- ORCID:
0000-0002-7961-8588 - ResearcherID:
F-6068-2017 - Google Scholar: https://scholar.google.com/citations?hl=en&user=pF2ra-YAAAAJ
- Scopus AuthorID:
7003722702
Публикации (53)
Shedding and interaction of solitons in weakly disordered optical fibers
2003 · ARTICLE · en
The propagation of the soliton pattern through optical fiber with weakly disordered dispersion coefficient is considered. Solitons perturbed by this disorder radiate and, as a consequence, decay. The average radiation profile is found. Emergence of a long-range intrachannel interaction between the solitons ~mediated by this radiation! is reported. We show that soliton in a multisoliton pattern experiences a random jitter: intersoliton separation is zero mean Gaussian random field. Fluctuations of this separation are estimated by d y ;Dz2Am, where D measures the disorder strength, z is the propagation distance, and m stands for the transmission rate ~number of solitons per unit length of the fiber!. Direct numerical simulations are used to validate theoretical predictions for single soliton decay and two-soliton interaction. Relevance of these results to fiber optics communication technology is discussed.
Compensation for extreme outages caused by polarization mode dispersion and amplifier noise
2003 · ARTICLE · en
Fluctuations of Bit-Error-Rate (BER) stimulated by birefringent disorder in an optical fiber system are found to be strong. The effect may not be analyzed in terms of the average BER but rather requires analyzing the Probability Distribution Function (PDF) of BER. We report the emergence of the extremely extended algebraic-like tail of the PDF, corresponding to anomalously large values of BER. We analyze the dependence of the PDF tail, and thus the outage probability, on the first-order PMD compensation scheme. Effectiveness of compensation is illustrated quantitatively using a simple, however, practical example.
Statistics of soliton-bearing systems with additive noise
2001 · ARTICLE · en
We present a consistent method to calculate the probability distribution of soliton parameters in systems with additive noise. Even though the noise is weak, we are interested in probabilities of large fluctuations ~generally non-Gaussian! which are beyond perturbation theory. Our method is a development of the instanton formalism ~method of optimal fluctuation! based on a saddle-point approximation in the path integral. We first solve a fundamental problem of soliton statistics governed by a noisy nonlinear Schro¨dinger equation. We then apply our method to optical soliton transmission systems using signal control elements ~filters and amplitude and phase modulators!.
Shedding and interaction of solitons in imperfect medium
2001 · ARTICLE · en
The propagation of a soliton pattern through one-dimensional medium with weakly disordered dispersion is considered. Solitons, perturbed by this disorder, radiate. The emergence of a long-range interaction between the solitons, mediated by the radiation, is reported. Basic soliton patterns are analyzed. The interaction is triple and is extremely sensitive to the phase mismatch and relative spatial separations within the pattern. This phenomenon is a generic feature of any problem explaining adiabatic evolution of solitons through a medium with frozen disorder.
Solitons in a disordered anisotropic optical medium
2001 · ARTICLE · en
The radiation-mediated interaction of solitons in a one-dimensional nonlinear medium (optical fiber) with birefringent disorder is shown to be independent of the separation between solitons. The effect produces a potentially dangerous contribution to the signal lost.
Passive scalar in a large-scale velocity field
1999 · ARTICLE · en
We consider advection of a passive scalar u (t,r) by an incompressible large-scale turbulent flow. In the framework of the Kraichnan model all PDF’s ~probability distribution functions! for the single-point statistics of u and for the passive scalar difference u (r1)2u (r2) ~for separations r12r2 lying in the convective interval! are found.
Intermittency in Burgers' Turbulence
1997 · ARTICLE · en
We consider the tails of probability density function (PDF) for the velocity that satisfies Burgers equation driven by a Gaussian large-scale force. The saddle-point approximation is employed in the path integral so that the calculation of the PDF tails boils down to finding the special field-force configuration (instanton) that realizes the extremum of probability. For the PDFs of velocity and its derivatives u(k)=∂kxu, the general formula is found: lnP(|u(k)|)∝−(|u(k)|/Rek)3/(k+1).
Viscous Instanton for Burgers' Turbulence
1997 · ARTICLE · en
We consider the tails of probability density functions (PDF) for different characteristics of velocity that satisfies Burgers equation driven by a large-scale force. The saddle-point approximation is employed in the path integral so that the calculation of the PDF tails boils down to finding the special field-force configuration (instanton) that realizes the extremum of probability. We calculate high moments of the velocity gradient $\partial_xu$ and find out that they correspond to the PDF with $\ln[{\cal P}(\partial_xu)]\propto-(-\partial_xu/{\rm Re})^{3/2}$ where ${\rm Re}$ is the Reynolds number. That stretched exponential form is valid for negative $\partial_xu$ with the modulus much larger than its root-mean-square (rms) value. The respective tail of PDF for negative velocity differences $w$ is steeper than Gaussian, $\ln{\cal P}(w)\sim-(w/u_{\rm rms})^3$, as well as single-point velocity PDF $\ln{\cal P}(u)\sim-(|u|/u_{\rm rms})^3$. For high velocity derivatives $u^{(k)}=\partial_x^ku$, the general formula is found: $\ln{\cal P}(|u^{(k)}|)\propto -(|u^{(k)}|/{\rm Re}^k)^{3/(k+1)}$.
Instantons and Intermittency
1996 · ARTICLE · en
We describe the method for finding the non-Gaussian tails of the probability distribution function (PDF) for solutions of a stochastic differential equation, such as the convection equation for a passive scalar, the random driven Navier-Stokes equation, etc. The existence of such tails is generally regarded as a manifestation of the intermittency phenomenon. Our formalism is based on the WKB approximation in the functional integral for the conditional probability of large fluctuation. We argue that the main contribution to the functional integral is given by a coupled field-force configuration—the instanton. As an example, we examine the correlation functions of the passive scalar u advected by a large-scale velocity field δ correlated in time. We find the instanton determining the tails of the generating functional, and show that it is different from the instanton that determines the probability distribution function of high powers of u. We discuss the simplest instantons for the Navier-Stokes equation. © 1996 The American Physical Society.
THEORY OF RANDOM ADVECTION IN TWO DIMENSIONS
1996 · ARTICLE · en
The steady statistics of a passive scalar advected by a random two-dimensional flow of an incompressible fluid is described at scales less than the correlation length of the flow and larger than the diffusion scale. The probability distribution of the scalar is expressed via the probability distribution of the line stretching rate. The description of the line stretching can be reduced to the classical problem of studying the product of many matrices with a unit determinant. We found a change of variables which allows one to map the matrix problem into a scalar one and to prove thus a central limit theorem for the statistics of the stretching rate. The proof is valid for any finite correlation time of the velocity field. Whatever be the statistics of the velocity field, the statistics of the passive scalar in the inertial interval of scales is shown to approach Gaussianity as one increases the Peclet number Pe (the ratio of the pumping scale to the diffusion one). The first n
Курсы (5)
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Семинар наставника · 3 раза
2024/2025, 2023/2024, 2022/2023 · Магистратура · рус
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Введение в статистическую гидродинамику · 2 раза
2022/2023, 2021/2022 · Бакалавриат · рус
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Дополнительные главы математической физики
2022/2023 · Бакалавриат · рус
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Научно-исследовательский семинар: ланжевеновская динамика и кинетика равновесных и неравновесных систем · 2 раза
2022/2023, 2021/2022 · Бакалавриат · рус
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Физическая кинетика
2021/2022 · Магистратура · рус