Hidden supersymmetry of a $P,T-$invariant $3D$ fermion system

Mikhail Plyushchay, Pasquale Sodano

We show that a (2+1)-dimensional $P,T-$invariant free fermion system, relevant to $P,T-$conserving models of high-$T_c$ superconductivity, has a U(1,1) dynamical symmetry as well a…