Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.

The organizing committee includes Malcolm Boshier (P-21), Diego Dalvit (T-4), Michael Di Rosa (C-PCS), Sebastian Deffner (T-4 & CNLS), Changhyun Ryu (P-21) , Nikolai Sinitsyn (T-4), Rolando Somma (T-4), Christopher Ticknor (T-1), and Wojciech Zurek (T-4).

For more information, or to nominate a speaker, contact Sebastian Deffner.

To add your name to the Quantum Lunch email list, contact Kacy Hopwood.

Thursday December 17, 2015
12:30 PM - 2:00 PM

Speaker: Maciej Maska (University of Silesia)

Technical Host: Bartlomiej Gardas

TOPIC: Effective approach to the boson-fermion model

Abstract
We consider a coupled boson-fermion model in two dimensions, that describes itinerant fermions hybridizing with localized bosons composed of pairs of tightly bound opposite-spin fermions. We trace out the fermionic degrees of freedom and perform a Monte Carlo simulation for the effective classical Hamiltonian of boson phases. We find that the fermions generate an effective long-range temperature-dependent phase-phase coupling. In the effective model we observe topological excitations similar to these in the XY model. Unbinding of vortex-antivortex pairs seems to lead to the Kosterlitz-Touless transition. Our results are relevant for resonance superfluids in the BCS-BEC crossover regime and also certain aspects of the high temperature superconductivity.