Itinerant Ferromagnetism in an Atom Trap

TL;DR

This paper proposes an experimental approach to study itinerant ferromagnetism in fermionic Hubbard systems, revealing topological magnetic ground states like skyrmions and hedgehogs in large traps.

Contribution

It introduces a method to map magnetic phase diagrams in fermionic systems and identifies topological magnetic structures in ground states.

Findings

Ground states exhibit topological features such as skyrmions and hedgehogs.

Large trap radii lead to topologically nontrivial magnetic configurations.

The proposed experiment enables exploration of magnetic phase transitions in cold atom systems.

Abstract

We propose an experiment to explore the magnetic phase transitions in interacting fermionic Hubbard systems, and describe how to obtain the ferromagnetic phase diagram of itinerant electron systems from these observations. In addition signatures of ferromagnetic correlations in the observed ground states are found: for large trap radii (trap radius $R_T > 4$, in units of coherence length $\xi$), ground states are topological in nature -- a "skyrmion" in 2D, and a "hedgehog" in 3D.