  Isotope separation is one of the grand challenges of modern society and holds
great potential for basic science, medicine, energy, and defense. We consider
here a new and general approach to isotope separation. The method is based on
an irreversible change of the mass-to-magnetic moment ratio of a particular
isotope in an atomic beam, followed by a magnetic multipole whose gradients
deflect and guide the atoms. The underlying mechanism is a reduction of the
entropy of the beam by the information of a single-scattered photon for each
atom that is separated. We numerically simulate isotope separation for a range
of examples, including lithium, for which we describe the experimental setup we
are currently constructing. Simulations of other examples demonstrate this
technique's general applicability to almost the entire periodic table. We show
that the efficiency of the process is only limited by the available laser
power, since one photon on average enables the separation of one atom. The
practical importance of the proposed method is that large-scale isotope
separation should be possible, using ordinary inexpensive magnets and the
existing technologies of supersonic beams and lasers.
