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Joint Mathematics and Physics Seminar

Masao Hirokawa, Lars Wacker and Nikolaj Zinner (Hiroshima, AU and AU)
Torsdag, 17 marts, 2016, at 12:15-16:00, in Aud. G1 (1532-116)
12:15--13:00 Masao Hirokawa Part I  Mathematical Modeling for Quantum Devices  

Abstract: In the first part of my talk, I would like to introduce what I 
would like  to do in Circuit QED through collaboration with some experimenters.

13:15-- 14:00.   Masao Hirokawa Part II.  Quantum Phase Transition

Abstract: In the last part, I would like to show the Hepp-Lieb-Preparata quantum  phase  transition appearing in circuit QED.

14:15--15:00. Lars Wacker  The Bose Polaron in an ultracold quantumgas  
Abstract: An impurity interacting with its surroundings leads to the formation of a quasi-particle, called a polaron. This was first described by Landau as a bosonic phonon gas, formed in a solid by the interaction of an electron with the lattice displacements. Ultracold gases offer superior control over the interparticle interaction and allowed for first experimental investigations of the Fermi polaron in ultracold Fermi gases.
Likewise, bosonic polarons can be investigated using mixtures of ultracold bosonic quantum gases. We employ a magnetic Feshbach resonance between two magnetic substates of 39 K to precisely tune the interaction between impurity and medium and perform spectroscopy between these states to record the energy spectrum. This allows us to distinguish between the mean field energy regime and the appearance of the polaronic signature in the spectrum.
 15:15--16:00 Nikolaj Zinner Strongly interacting few-body systems in 1D traps

Abstract:  I will outline a procedure for finding solutions of strongly interacting  particles confined to a one-dimensional trap. I will show how this  problem can be mapped onto a Heisenberg spin model. Furthermore,  I will argue that knowing the solution at weak and strong interaction  strength can be used to describe the system for any intermediate  interaction strength with very high accuracy. 
Kontaktperson: Jacob Schach Møller