Optical activity induced by rotation of atomic spin

Summary Physical systems or processes invariant under mirror reflection are not expected to exhibit intrinsically chiral asymmetries. Thus, it is ordinarily the case that unbounded and unexcited atoms (in the absence of weak nuclear interactions) should not manifest circular birefringence. It is shown, however, that in a rotating reference frame the coupling of atomic spin angular momentum to the angular velocity of the rest frame gives to optical activity even in the absence of contributions from nuclear interactions and the classical Coriolis force. Ground-state atomic hydrogen is predicted to be optically active in the microwave region near the hyperfine splitting frequency of 1420 MHz. Under appropriate circumstances, this spin-associated rotational circular birefringence can be some ten orders of magnitude larger than that previously estimated for virtual electronic transitions falling within the visible and UV portions of the spectrum.