Understanding the quantum phases of interacting fermions is a fundamental, chanllenging problem in many-body physics. Broken symmetry phases, such as spin density wave order in antiferromagnetic metal Chromium, or the p-wave superfluid order in liquid Helium 3, have long been known and well understood. Motivated by recent experiments, we find theoretically that an unconventional spin-density wave phase with p-wave orbital symmetry in ultracold Fermi gases of polar molecules and magnetic atoms. It is a kind of magnetic order formed on bonds connecting the lattice sites, and can be viewed as the particle-hole analog of p-wave superconductivity.
Unconventional Spin Density Waves in Dipolar Fermi Gases, S. G. Bhongale, L. Mathey, Shan-Wen Tsai, Charles W. Clark, Erhai Zhao, arXiv:1209.2671