[Landau ITP Seminars] Friday 03.10.2025

[Stanislav Apostolov]

Уважаемые коллеги!

На заседании Ученого совета ИТФ в пятницу 03.10 будет заслушан доклад:

11:30

M. A. Skvortsov, A. V. Polkin
Thermal phase slips in superconducting films and Boussinesq equation

A dissipationless supercurrent state in superconductors can be destroyed 
by thermal fluctuations. Thermally activated phase slips provide a 
finite resistance of the sample and are responsible for dark counts in 
superconducting single photon detectors. The activation barrier for a 
phase slip is determined by a space-dependent saddle-point (instanton) 
configuration of the order parameter. In the one-dimensional wire 
geometry, such a saddle point has been analytically obtained by Langer 
and Ambegaokar in the vicinity of the critical temperature, $T_c$, and 
for arbitrary bias currents below the critical current $I_c$. In the 
two-dimensional geometry of a superconducting strip, which is relevant 
for photon detection, the situation is much more complicated. Depending 
on the ratio $I/I_c$, several types of saddle-point configurations have 
been proposed, with their energies being obtained numerically. We 
demonstrate that the saddle-point configuration for an infinite 
superconducting film at $I\to I_c$ is described by the exactly 
integrable Boussinesq equation solved by Hirota's method. The 
instanton size is $L_x\sim\xi(1-I/I_c)^{-1/4}$ along the current and 
$L_y\sim\xi(1-I/I_c)^{-1/2}$ perpendicular to the current, where $\xi$ 
is the Ginzburg-Landau coherence length. The activation energy for 
thermal phase slips scales as $\Delta F^\text{2D}\propto 
(1-I/I_c)^{3/4}$. For sufficiently wide strips of width $w\gg L_y$, a 
half-instanton is formed near the boundary, with the activation energy 
being 1/2 of $\Delta F^\text{2D}$.

ID и пароль онлайн-трансляций в Zoom те же, что и для предыдущих 
трансляций семинаров и докладов на Ученом совете:
https://zoom.us/j/96899364518?pwd=MzBsR2lYT0lYL2x2b1oyNU9LeWlWUT09
Meeting ID: 968 9936 4518
Пароль: 250319

Просьба присутствовать на заседании членов Учёного совета в связи с 
голосование открытым, поднятием "виртуальной" руки.

На завтра 03.10.25г. в 10-05 автобус запланирован.

Место сбора 11-я парковая, поворот на Щелковское шоссе.
Форд-Транзит  А 797МА 150

тел. 8-903-019-86-80
Владимир Николаевич

https://yandex.ru/maps/213/moscow/?from=mapframe&indoorLevel=1&ll=37.804151%2C55.809870&mode=usermaps&source=mapframe&um=constructor%3A1gjtTU9HvRzE3mvpCCP6B_Io424BFoMD&utm_source=mapframe&z=17.4 
[1]



Links:
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[1] 
https://yandex.ru/maps/213/moscow/?from=mapframe&indoorLevel=1&ll=37.804151%2C55.809870&mode=usermaps&source=mapframe&um=constructor%3A1gjtTU9HvRzE3mvpCCP6B_Io424BFoMD&utm_source=mapframe&z=17.4
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