| 摘要 |
Measuring a magnetic gradient according to the present invention includes generating a beam of like atoms with magnetic sublevels, applying a first pulse of electro-magnetic radiation to the beam of atoms to create a coherent superposition of the magnetic sublevels in the atoms in which the superposition results in a plurality of beams following separate paths and in which at least two of the paths are arms of an interferometer, applying a second pulse of electromagnetic radiation to both beams of atoms a time T later with characteristics substantially similar to the first pulse and in which the product of the Rabi frequency and T now must equal &pgr; (versus &pgr;/2 in the first pulse), whereby the states of the atoms in the two arms of the interferometer are coherently interchanged and are redirected towards each other. The beams of atoms are then recombined by apply a third pulse of electromagnetic radiation a time T±&Dgr;t after the second pulse with characteristics substantially similar to the first pulse such that the paths form a closed loop. Then, a detecting pulse of light is used to detect the number of atoms in one magnetic sublevel versus another magnetic sublevel.
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