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Yaroslav Lutsyshyn “Elastic transmission of particles through strongly correlated Bose liquid.”, Alexey Golomedov “Monte Carlo simulation of 2D system of excitons”

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Jun 16, 2015 from 09:00 AM to 10:00 AM (Europe/Madrid / UTC200)

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SEMINAR ANNOUNCEMENT

Wednesday, 21 January 2009 at 10:30
UPC campus nord, B4-212

1) Yaroslav Lutsyshyn
UPC, formerly University of Minnesota
 
“Elastic transmission of particles through strongly correlated Bose liquid.”

2) Alexey Golomedov
Moscow State University
 
“Monte Carlo simulation of 2D system of excitons”

Abstract

A mesoscopic system of indirect dipolar excitons trapped by an harmonic potential is considered. Indirect exciton is formed when an electron from one layer of the quantum coupled wells structure gets coupled to a hole from the other layer. Such an exciton is a composite boson. Due to the spacial separation of electrons and holes indirect exciton possess a dipole moment, d = e D, where D is the separation between layers. The repulsive dipolar interaction between excitons suppresses the inter-excitons recombination effects making the life time of an indirect exciton much longer then for direct exciton (for wich electron and hole from the same well are bounded).  Due to Bose-Einstein statistic excitons can Bose condense, the condensation should occur at temperatures near 1K.

We carry out a Quantum Monte Carlo simulation to define the properties of the system at zero temperature. In dimensionless units the system is described by two parameters, namely the number of particles and the strength of the interparticle interaction. We have shown that when the interparticle interaction is strong enough mesoscopic crystal is formed. With the interaction weakening multi-stage melting takes place. We also have found that the system is Bose-condensed even in the case of strong interparticle interactions, there is a set of the parameters where crystal-like structure is formed and fraction of Bose-condensate is non zero.