We construct a generalization of the quantum Ha effect, where particles mov
e in four dimensional space under a SU(2) gauge field. This system has a ma
croscopic number of degenerate single particle states. At appropriate integ
er or fractional filling fractions the system forms an incompressible quant
um liquid. Gapped elementary excitation in the bulk interior and gapless el
ementary excitations at the boundary are investigated.