Exact SO(5) symmetry in the spin-3/2 fermionic system

Phys Rev Lett. 2003 Oct 31;91(18):186402. doi: 10.1103/PhysRevLett.91.186402. Epub 2003 Oct 28.

Abstract

The spin-3/2 fermion models with contact interactions have a generic SO5 symmetry without any fine-tuning of parameters. Its physical consequences are discussed in both the continuum and lattice models. A Monte Carlo algorithm free of the sign problem at any doping and lattice topology is designed when the singlet and quintet interactions satisfy U0< or = U2< or = -3/5 U0 (U0< or = 0), thus making it possible to study different competing orders with high numerical accuracy. This model can be accurately realized in ultracold atomic systems.