alt FUW
logo UW
other language
webmail
search
menu
2021-11-25 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15  Calendar icon
dr Paweł Jung (CREOL, The College of Optics and Photonics at University of Central Florida)

Nonlinear dynamics in complex optical systems

In recent years, the complex nonlinear response of optical systems, such as strong competing nonlocal interactions in soft matter or weakly nonlinear highly multimode topological and trivial arrangements, has attracted considerable attention. To a great extent, what has motivated this interest is a quest for robust all-optical switching and high-power optical sources that has been enabled by a sequence of new developments in multimode technologies on both guided-wave structures and photonic cavities. However, as lately indicated in a number of studies, the action of nonlinearity, including the interplay of nonlinearity and topology in photonic configurations, can lead to a host of novel effects that have never been observed before. In this talk, several of our recent results will be presented concerning a topologically protected light transport, a new class of solitons arising from nonlocal interactions, and a new optical thermodynamic framework suited for highly complex nonlinear multimode systems.

Internet seminar: https://zoom.us/j/97696726563 (meeting ID: ID 97696726563, password: 314297)
2021-11-18 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15  Calendar icon
prof. dr hab. Witold Bardyszewski (Institute of Theoretical Physics of the Faculty of Physics UW)

The photonic persistent spin helix as a manifestation of the classical entanglement in tunable liquid crystal microcavities

seminar using internet connection: https://zoom.us/j/97696726563 [1] (MEETING ID: ID 97696726563, PASSWORD: 314297)
2021-11-11 (Czwartek)
Zapraszamy do sali B2.38, ul. Pasteura 5 o godzinie 10:15  Calendar icon
(IFD UW)

Uprzejmie informuję, że seminarium 11 listopada nie odbędzie się

We'd like to inform that the seminar on November 11 will not be held

2021-11-04 (Czwartek)
Zapraszamy do sali B2.38, ul. Pasteura 5 o godzinie 10:15  Calendar icon
dr Matthew Frye (IFT UW)

Complexes formed in collisions between ultracold alkali-metal diatomic molecules and atoms

Ultracold molecules are promising for many applications including quantum simulation andcontrolled chemistry, but they often suffer from rapid collisional loss, even when there areapparently no energetically accessible loss channels. Here we investigate collisions of alkalimetaldiatoms with atoms, and the effects of different types of collision complexes that canbe formed. First we consider dense and chaotic short-range collision complexes, which arethought to drive collisional loss via laser excitation. These have previously been consideredin terms of a statistically averaged effect of a dense spectrum, but we show that even for theheaviest diatom+atom systems, ultracold collisions at around 1 μK instead see the effects ofindividual states; the corresponding features in the scattering are very broad on anexperimental scale. In a second study we analyze a large set of experimentally observedmagnetic Feshbach resonances for NaK+K. We conclude that they are not members of thechaotic bath of short-range states discussed in the first part of this talk. Instead, they are mostlikely simple long-range states with the character of the separated atom and molecule. Thesetwo studies highlight contrasting aspects of ultracold atom+diatom scattering and bring uscloser to understanding and ultimately harnessing ultracold molecular collisions.
2021-10-28 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15  Calendar icon
(IFD UW)

Uprzejmie informujemy, że seminarium w dniu 28 października jest odwołane

2021-10-21 (Czwartek)
Zapraszamy do sali B2.38, ul. Pasteura 5 o godzinie 10:15  Calendar icon
dr Giacomo Roati (CNR-INO oraz LENS, Florence , Italy)

A quantum vortex collider

Quantum vortices occur in a wide range of systems, from atomic Bose–Einstein condensatesto superfluid helium liquids and superconductors. Their dynamics is associated with theonset of dissipation, which makes the superflow no longer persistent [1]. Paradigmaticexamples are the motion of Abrikosov vortices which determines the resistance of the type-IIsuperconductors or the vortex dynamics in helium superfluids, where the mutual frictionbetween the normal and superfluid components plays a key role in superfluid turbulence.In this work, we study the fundamental mechanisms of vortex energy dissipation by realisinga versatile two-dimensional vortex collider in homogeneous atomic Fermi superfluids acrossthe BEC-BCS crossover [2]. We unveil vortex-sound interactions by observing theconversion of the energy of vortex swirling flow into sound energy during vortexcollisions. We visualise vortices annihilating into sound waves, i.e., the ultimate outcome ofsmall-scale vortex collisions, and we find indications of the essential role played by vortexcore-bound fermionic excitations in strongly-correlated fermion superfluids. Ourprogrammable platform opens the route to exploring new pathways for quantum turbulencedecay, vortex by vortex.[
2021-10-14 (Czwartek)
Zapraszamy na spotkanie o godzinie 10:15  Calendar icon
dr Rafał Szabla (Uniwersytet w Edynburgu)

Using quantum chemistry to understand the origins of RNA and DNA

2021-10-07 (Czwartek)
Zapraszamy do sali B2.38, ul. Pasteura 5 o godzinie 10:15  Calendar icon
dr Stéphane Clemmen (Université Libre de Bruxelles & Ghent University)

Versatile single photons sources using active frequency multiplexing

Wersja desktopowa Stopka redakcyjna