3 seminars coming up

[Cond.Matt. & Stat.Mech.Section]

  JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR



  Tuesday, 8 June   -   11:30 hrs.



  Luigi Stasi Seminar Room,  ICTP Leonardo Building - 1st floor



  Ariel AMIR   (The Weizmann Institute of Science, Rehovot)



"Localization, anomalous diffusion and   slow relaxations in  
disordered systems"



Abstract



We present a model, that while simple to define, shows rich behavior  
that accounts for a variety of physical phenomena, such as  
localization of phonons, anomalous diffusion, and slow relaxations in  
glassy systems.  The 'crux of the matter' lies in the fact that the  
rate of many processes in nature is exponential in the relevant  
distance: quantum tunneling is a common example.  If we think about a  
particle diffusing in a random environment, its dynamics will be  
described by a matrix A where the i,j'th element is exponential in the  
distance between points i and j.  This leads us naturally to the model  
of exponential random matrices, which is a novel ensemble of random  
matrices, with interesting properties.  We solve the model exactly,  
and discuss the implications on the various physical problems.

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INFORMAL SEMINAR



Wednesday, 9 June   -    4:00 p.m.


Luigi Stasi Seminar Room -  Leonardo Bldg. - first floor


Mikhail V. FEIGELMAN  (L.D. Landau Institute for Theoretical Physics,  
Moscow)



"Quantum spin metal state on a   decorated honeycomb lattice"



Abstract

We present a modification of exactly solvable spin-(1/2) Kitaev model  
on the decorated honeycomb lattice, with a ground state of "spin  
metal" type.  The model is diagonalized in terms of Majorana fermions;  
the latter form a 2D gapless state with a Fermi-circle those size  
depends on the ratio of exchange couplings.  Low-temperature heat  
capacity C(T) and dynamic spin susceptibility \chi(\omega,T) are  
calculated in the case of small Fermi-circle.  Whereas C(T)\sim T at  
low temperatures as it is expected for a Fermi-liquid, spin  
excitations are gapful and \chi(\omega,T) demonstrate unusual  
behaviour with a power-law peak near the resonance frequency.  The  
corresponding exponent as well as the peak shape are calculated.

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SEMINAR on   Disorder and strong electron correlations





Thursday, 10 June   -  11:30 a.m.





Luigi Stasi Seminar Room,  Leonardo Building - first floor



Walter R. HOFSTETTER      ( Johann Wolfgang Goethe-Universität,  
Frankfurt )



"Magnetic and color superfluid order in multiflavor Fermi gases"



Abstract



Cold atoms in optical lattices offer a new laboratory for quantum many- 
body phenomena.  One of their main advantages is the tunability of  
interactions and quantum statistics. In this talk I will focus on  
current developments in multiflavor Fermi gases:

i) We investigate antiferromagnetic ordering of trapped spin-1/2  
fermions using large-scale dynamical mean-field theory simulations.   
We find a clear experimental signature - enhanced double occupancy -  
for the onset of magnetic order at low temperatures in current  
experiments.

ii) We study the properties of three-flavor fermions in an optical  
lattice, where new exotic quantum states such as color superfluids  
arise in partial analogy to Quantum Chromodynamics.  Low-temperature  
properties of this system are addressed using DMRG and dynamical mean- 
field theory.  We find a strong interplay between magnetization and  
color superfluidity.