Lets say we emit a photon from the ground out towards the sky , and as the photon travels away from earth it gets red-shifted . In stead of canceling the shift by using the Doppler effect like they did in the pound-rebka experiment , we use the zeeman effect to alter the discrete energy levels of the electron orbiting the atom so that the atom will absorb the photon after the red-shift , and we assume the original photon at ground level was emitted from an atom that had a difference in energy from n=2 to n=1 , and then we cancel the shift with the zeeman effect so that the photon will excite the atom after the shift from n=1 to n=2 . Would this imply that clocks tick at different rates in different B fields . Excluding the gravitational effect from the B field . Or am i missing something here .