Anomalous behavior of spin systems with dipolar interactions
In this project, we studied the properties of spin systems realized by cold polar molecules interacting via dipole-dipole interactions in two dimensions. Using a spin wave theory, that allows for the full treatment of the characteristic long-distance tail of the dipolar interaction, we found several anomalous features in the ground state correlations and the spin wave excitation spectrum, which are absent in their counterparts with short-range interaction. The most striking consequence is the existence of true long-range order at finite temperature for a two-dimensional phase with a broken U(1) symmetry.
- Anomalous Behavior of Spin Systems with Dipolar Interaction
D. Peter, S. Müller, S. Wessel, and H. P. Büchler, Phys. Rev. Lett 109, 025303 (2012)
Driving Dipolar Fermions into the Quantum Hall Regime
A new method to drive a system of neutral dipolar fermions into the lowest Landau level regime was proposed. By employing adiabatic spin-flip processes in combination with a diabatic transfer, the fermions are pumped to higher orbital angular momentum states in a repeated scheme that allows for the precise control over the final angular momentum. A simple analytical model was derived to quantify the transfer and compare the approach to rapidly rotating systems. Numerical simulations of the transfer process were performed for small, interacting systems.
- Driving Dipolar Fermions into the Quantum Hall Regime by Spin-Flip Induces Insertion of Angular Momentum
D. Peter, A. Griesmaier, T. Pfau, and H. P. Büchler, Phys. Rev. Lett. 110, 145303 (2013)