[Landau ITP Seminars] Colloquium Friday 12.11.2021

[Serge Krashakov]

Уважаемые коллеги!

В пятницу 12 ноября в 11:30 состоится коллоквиум с докладом:

John Chalker (Physics Department, University of Oxford)
*Many-body delocalisation as symmetry breaking*

I will start this talk with an overview of recent work on quantum 
dynamics in many body systems far from equilibrium. This work has led to 
an understanding from the perspective of quantum information, of how a 
such systems may approach an equilibrium state at long times, in which 
initial conditions are effectively forgotten. It has also led to an 
appreciation that there are classes of system in which an equilibrium 
state is not reached at long times. One of these classes is made up of 
many-body localised systems, in which randomness in the Hamiltonian is 
responsible for a long-lived memory of the initial state of a system. By 
varying the strength of randomness, a transition can be induced between 
localised and ergodic phases, which seems very different from 
conventional symmetry-breaking phase transitions.
In the second part of the talk I will discuss minimal models for quantum 
chaos and many-body localisation. The models are Floquet quantum 
circuits for lattice spin systems, in which time evolution is generated 
by unitary gates that couple neighbouring sites. In particular, I will 
examine the circumstances in which a version of the so-called diagonal 
approximation (originally developed for the semiclassical limit in 
low-dimensional chaotic systems) can be applied to these systems. Within 
this framework I will show that the many-body delocalisation transition 
can be seen as a form of symmetry breaking transition, having many of 
the features generally associated with conventional phase transitions in 
classical statistical mechanical models.

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

Для приезда в Институт можно воспользоваться автобусом, который будет 
организован по записи при числе желающих не менее 5.
Для записи на автобус из Москвы в Черноголовку необходимо до 18:00 
четверга отправить письмо на адрес электронной почты bus at itp.ac.ru. 
После этого записавшимся до 20:00 поступит подтверждение об отправке или 
неотправке автобуса в зависимости от числа записавшихся.
Запись на обратный автобус - как и раньше на Ученом совете.
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