Fermionic quantum memory
A fermionic quantum system is an example of a constrained system due to the presence of superselected symmetries. We investigate the presence of localised states in such systems and find that in the presence of an additional global permutation symmetry the system completely localises without the presence of any disorder coefficients. Furthermore these states are stable to perturbations that preserve the global permutation symmetry providing an example of a fermionic quantum memory. The systems proposed here can be realised in superconducting quantum circuits and trapped ion systems.