We comment on the relation between Berry phase and quantized Hall
conductivities for charge and spin currents in some Bloch states, such as Bloch
electrons in the presence of electromagnetic fields and quasiparticles in the
vortex states of superfluid 3He. One can find out that the arguments
presented here are closely related to the spontaneous polarization in
crystalline dielectrics and the adiabatic pumping.Comment: 2 pages, 1 figure, to be published in the proceedings of LT23 in
Hiroshima, Aug. 200