Colóquio: "Experiments on superfluid atomic Fermi gases across the BEC-BCS crossover" - Giacomo Roati - INO-CNR and LENS - Florence - Italy

abr/25 10:00
Auditorio 1 - no prédio da Biblioteca
terça-feira, 25 Abril, 2017 - 10:00
Auditorio 1 - no prédio da Biblioteca
I will  present our  recent experimental  studies on  superfluid Fermi gases  of 6Li  atoms across  the BEC-BCS  crossover. Ultracold  atomic Fermi gases  are considered  as ideal  and versatile  toolbox where to investigate the physics of strongly-correlated fermionic systems  [1].
In our experiment, we create the analogous of a Josephson junction  by bisecting BEC-BCS crossover superfluids by a thin optical barrier.  We observe coherent dynamics in both  the population and in the  relative phase  [2].
For  large  bias  potentials  across  the  junction,  the superfluid  dynamics  exhibits   both  coherent  oscillations   and  a resistive  flow due  to phase-slippage  events, arsing  from vortices propagating  into  the  bulk.  We  also  study  the  regime  of strong dissipation when  the junction  operation is  irreversibly affected by vortex  proliferation,  causing  the  loss  of  coherence  between the superfluid reservoirs [3].
[1]  Proceedings  of the  Enrico  Fermi School,  Course  191, ”Quantum Matter at Ultralow Temperatures” (2016), IOS Press (Amsterdam)
[2] G. Valtolina et al., Science 350, 1505 (2015)
[3] A. Burchianti et al. in preparation