1305.6361 (Xiaoling Cui et al.)

Ferromagnetic Transition in Strongly Repulsive One-Dimensional Fermi
Gases in Arbitrary Potential with Arbitrary Particle Number    [PDF]

Xiaoling Cui, Tin-Lun Ho

We prove that a one-dimensional strongly repulsive Fermi gas will undergo a ferromagnetic transition at infinite repulsion. The transition is facilitated by the large spin degeneracy at infinite repulsion, which also allows arbitrarily tiny symmetry breaking field to destroy spin conservation to bring the system to the ferromagnetic ground state. The signature of this transition will show up prominently as large spin density fluctuations, as well as formation of large magnetic domains under symmetry breaking fields. We have demonstrated all these effects by exact calculations, and have worked out the quantum mechanical wavefunction that exhibits phase separation.

View original: http://arxiv.org/abs/1305.6361