IJS KOLOKVIJ,petek, 28. 03. 2014; ob 13. uri; prof. dr. Benoît Deveaud-Plédran

[Tanja Debevec]

Vabimo vas na 13. predavanje iz sklopa "Kolokviji na IJS" v letu 2013/14, ki bo v petek, 28. marca 2014, ob 13. uri v Veliki predavalnici Instituta »Jožef Stefan«  na Jamovi cesti 39 v Ljubljani. Napovednik predavanja najdete tudi na naslovu http://www.ijs.si/ijsw/Koledar_prireditev, posnetke preteklih predavanj pa na http://videolectures.net/kolokviji_ijs. 

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Prof. dr. Benoît Deveaud-Plédran

Ecole Polytechnique Fédérale de Lausanne, Lozana, Švica

 

Vrtinci in superfluidnost v ekscitonsko-polaritonskih kondenzatih 

Polaritoni so fascinantni kvazidelci, ki izhajajo iz sklopitve med fotoni in ekscitoni (pari elektronov in vrzeli v polprevodnikih). Polaritonski kondenzati lahko nastanejo spontano preko “standardnega” faznega prehoda proti Bose-Einsteinovem kondenzatu ali pa jih induciramo resonančno z jasno določeno fazo, hitrostjo in prostorsko porazdelitvijo. Zaradi fotonske komponente polaritonov je mogoče lastnosti kvantne tekočine študirati zelo neposredno, še posebej preko podrobnih interferometričnih meritev. Tako lahko npr. izjemno preprosto določimo koherenčne lastnosti kvantne tekočine na velikih razdaljah. Obenem je moč z veliko prostorsko in časovno natančnostjo izmeriti lastnosti superfluida. Tu bomo opisali statiko in dinamiko vrtincev v polaritonskih kondenzatih, dobljeno s pikosekundno časovno ločljivostjo v različnih konfiguracijah. Pokazali bomo dinamiko spontanega nastanka vrtinca in razpad vrtinca na dva polovična. Poudarili bomo nekatere od nedavnih rezultatov, ki smo jih dobili s preoblikovanjem sistema bodisi z uporabo nanotehnologije bodisi s povsem optičnimi pristopi ali z obojim, kar omogoča raziskave superfluidne hidrodinamike polaritonskih tekočin.

Predavanje bo v angleščini.

Lepo vabljeni!

 

 

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We invite you to the 13th Institute colloquium in the academic year 2013/14. The colloquium will be held on Friday March 28, 2014 at 13 PM in the main Institute lecture hall, Jamova 39, Ljubljana. To read the abstract click  http://www.ijs.si/ijsw/Koledar_prireditev. Past colloquia are posted on  http://videolectures.net/kolokviji_ijs.

 

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Prof. dr. Benoît Deveaud-Plédran

Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

 

Vortices and superfluidity in exciton-polariton condensates

 

Polaritons are amazing quasiparticles originating from the coupling of photons with excitons (electron‐hole pairs in semiconductors). Polariton condensates may be created both spontaneously through a “standard” phase transition towards a Bose-Einstein condensate, or be resonantly driven with a well‐defined initial phase, speed and spatial distribution. Thanks to the photonic component of polaritons, the properties of the quantum fluid may be accessed very directly, with in particular the possibility of detailed interferometric studies. This allows for example to probe the long‐range coherence properties of a quantum fluid with unprecedented ease. This also allows testing superfluid properties with great precision in space and time. Here, I will describe the static and dynamics of vortices in polariton condensates, obtained with a picosecond time resolution, in different configurations, with in particular their phase configuration. I will show in particular the dynamics of spontaneous creation of a vortex as well as the dissociation of a full vortex into two half vortices. I will also highlight some of the recent results obtained through the shaping of the system, either using nanotechnology processes, or using all optical means, or both of them. This allows in particular the study superfluid hydrodynamics of polariton fluids.

 

We look forward to meeting you at the “Kolokvij na IJS”!

 

 

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