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Dear colleagues, <br>
<br>
I would like to invite you to the following seminar, <br>
<br>
<br>
Dr. Fabio Franchini<br>
(Ruđer Bošković Institute)<br>
<br>
"<span style=" color:#000000;">Universal dynamics of a localized </span><span
style=" color:#000000;">excitation after an interaction quench</span>"<br>
<br>
Tuesday, 22nd of November, 14:15h, F-201<br>
<br>
We study the time evolution, induced by a quench, of local
excitations in one dimension. We focus on interaction quenches: the
considered protocol consists in creating a stable localized
excitation propagating through the system, and then operating a
sudden change of the interaction between the particles. To highlight
the effect of the quench, we take the initial excitation to be a
soliton. The quench splits the excitation into two packets moving in
opposite directions, whose characteristics can be expressed in a
universal way. Our treatment, which is hydrodynamic in nature,
allows to describe the internal dynamics of these two packets in
terms of the different velocities of their components. We confirm
our analytical predictions through numerical simulations performed
with the Gross-Pitaevskii equation and with the Calogero model (as
an example of long range interactions and solvable with a parabolic
confinement). Through the Calogero model we also discuss the effect
of an external trapping on the protocol. The hydrodynamic approach
shows that there is a difference between the bulk velocities of the
propagating packets and the velocities of their peaks: it is
possible to discriminate the two quantities, as we show through the
comparison between numerical simulations and analytical estimates.
In the realizations of the discussed quench protocol in a cold atom
experiment, these different velocities are accessible through
different measurement procedures.<br>
<br>
<br>
Best regards,<br>
Ivica Smolić<br>
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