0000000000460482
AUTHOR
Andreas Daniel Pfister
Experimental realization of fast ion separation in segmented Paul traps
We experimentally demonstrate fast separation of a two-ion crystal in a microstructured segmented Paul trap. By the use of spectroscopic calibration routines for the electrostatic trap potentials, we achieve the required precise control of the ion trajectories near the critical point, where the harmonic confinement by the external potential vanishes. The separation procedure can be controlled by three parameters: a static potential tilt, a voltage offset at the critical point, and the total duration of the process. We show how to optimize the control parameters by measurements of ion distances, trap frequencies, and the final motional excitation. We extend the standard measurement technique…
Dynamical mean-field theory versus second-order perturbation theory for the trapped two-dimensional Hubbard antiferromagnet
In recent literature on trapped ultracold atomic gases, calculations for two-dimensional (2D) systems are often done within the dynamical mean-field theory (DMFT) approximation. In this paper, we compare DMFT to a fully 2D, self-consistent second-order perturbation theory for weak interactions in a repulsive Fermi-Hubbard model. We investigate the role of quantum and of spatial fluctuations when the system is in the antiferromagnetic phase, and find that, while quantum fluctuations decrease drastically the order parameter and critical temperatures, spatial fluctuations only play a noticeable role when the system undergoes a phase transition, or at phase boundaries in the trap. We conclude f…