  Many textbook physical effects in crystals are enabled by some specific
symmetries. In contrast to such "apparent effects", "hidden effect X" refers to
the general condition where the nominal global system symmetry would disallow
the effect X, whereas the symmetry of local sectors within the crystal would
enable effect X. Known examples include the hidden Rashba and/or hidden
Dresselhaus spin polarization that require spin orbit coupling, but (unlike the
apparent Rashba and Dresselhaus counterparts) can exist even in
inversion-symmetric non-magnetic crystals. Here we point out that the spin
splitting effect that does not require spin-orbit coupling (SOC) can have a
hidden spin polarization counterpart in antiferromagnets. We show that such
hidden, SOC-independent effects reflect intrinsic properties of the perfect
crystal rather than an effect due to imperfections, opening the possibility for
experimental realization, and offering a potential way to switch
antiferromagnetic ordering.
