2 CM seminars coming up

[CM]

SEMINAR on  Disorder and strong electron correlations




Thursday, 23 April-  11:00 a.m. 




Seminar Room,  Leonardo Building - first floor




Philippe LECHEMINANT  (University of Cergy-Pontoise)




"Trions and quartet condensates in  one-dimensional multicomponent 
ultracold fermions"


Abstract


In this talk, we will discuss the possible stabilization of a molecular superfluid phase in multicomponent attractive Fermi gas where more than two fermions form a bound state. We will show, by means of a low-energy approach and large scale DMRG calculations, that trionic (three-body bound states) and quartet phases emerge in multicomponent ultracold fermions loaded into one-dimensional  optical lattice at sufficiently small density.

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JOINT ICTP/SISSA CONDENSED MATTER SEMINARS




Seminar Room - ICTP Leonardo Building (first floor)




Wednesday, 29 April -     4:00 p.m.




Alberto PETRI  (CNR - Istituto dei Sistemi Complessi, Rome)



"Stochastic approach to chaotic stick-slip in granular systems"



Abstract

The sliding of contacting surfaces is a formidable problem with impact in many areas, ranging from atomic to tectonic in scale. In several cases it can result in steady sliding or periodic stick-slip motion, but often displays an intermittent and erratic nature, for which effective descriptions are lacking. In order to investigate  this kind of dynamics we have set up an experiment in which a  rigid plate engages in stick-slip shear motion on a granular bed.  In order to describe the resulting  motion we have adopted an unusual approach which is not deterministic in nature (as opposed to, e.g. Burridge-Knopoff and Frenkel-Kontorova models), finding that the dynamics can be accurately described in a quantitative way by  a simple stochastic equation, in which the resulting force exerted  by the medium on the plate performs a random walk.  Further work  on the statistical properties of friction in solid-on-solid systems and comparisons with other phenomena suggest that a large class of driven instabilities can be described in terms of similar general mechanisms. Preliminary results on variable height and shaken granular bed are presented.