Magnetic Correlations in Cold Atomic Systems

Igor Ferrier-Barbut

Lia Izabella Lovas

Pavao Santak

Physicists have been trying to create artificial magnetic systems using ultra-cold atomic gases as their simulators. However, behavior of many ultra-cold atomic systems is not very well understood yet. Ultra-cold fermionic alkaline earth atomic (AEA) gases are one of those systems. In this thesis, we study the effects of thermal fluctuations on the overall macroscopic behavior of ultra-cold fermionic AEA gases using a particular semiclassical model. We study the AEA systems on a square lattice with periodic boundary conditions. To investigate the behavior of AEA systems under the effects of thermal fluctuations, we analyze several different types of correlation functions, which correspond to different physical observables. We analyze the correlation functions using the results obtained from Monte Carlo simulations. We show that for the cases studied, all the correlation functions approach zero as the system size goes to infinity at any temperature, indicating that no phase transition occurs as a consequence of thermal fluctuations.

Lexter Savio Rodriguez

Bruno Juliá-Díaz, Daniel Dagnino, Kenneth Günter +4 more

Using exact diagonalization for a small system of cold bosonic atoms, we analyze the emergence of strongly correlated states in the presence of an artificial magnetic field. This gauge field is generated by a laser beam that couples two internal atomic states, and it is related to Berry's geometrical phase that emerges when an atom follows adiabatically one of the two eigenstates of the atom-laser coupling. Our approach allows us to go beyond the adiabatic approximation, and to characterize the generalized Laughlin wave functions that appear in the strong magnetic-field limit.

C. Broholm, G. Aeppli