Photon Scattering from Atoms in an Atom Interferometer: Coherence Lost and Regained
Loss of coherence in one system A that results from entanglement or correlation with a reservoir M has long been an important issue in quantum mechanics. It is of special interest both because of the difficulty of incorporating the resulting coherence loss into Schrödinger’s equation describing system A and because of its relevance to understanding the measurement process in particular and the connection between quantum mechanics and classical mechanics in general . We discuss experiments here in which this entanglement results from the elastic scattering of a photon from an atom initially in a state with extended spatial coherence inside an atom interferometer. The major issues addressed are the degree of loss of coherence (ie. contrast of the interference fringes), both when the outgoing photon is ignored (ie. treated as a reservoir) and when information about its final state is inferred from the final momentum of the atom. This inference is exact since momentum (and energy too) is conserved and the initial momentum of both photon and atom are well specified.
KeywordsInterference Fringe Atomic Beam Photon Scattering Fringe Visibility Atom Interferometer
Unable to display preview. Download preview PDF.
- 1.J.A. Wheeler and W.H. Zurek. Quantum Theory and Measurement ( Princeton University Press, Princeton, 1983 ).Google Scholar
- 2.N. Bohr in A. Einstein: Philosopher - Scientist edited by P. A. Schilpp p. 200–241 (Library of Living Philosophers, Evaston, 1949); a detailed analysis is given in: W. Wooters and W. Zurek, Phys. Rev. D 19 473 (1979).Google Scholar
- 3.R. Feynman, R. Leighton and M. Sands. The Feynman Lectures on Physics (Addison-Wesley, Reading, MA, 1965)vol. 3, p. 5–7Google Scholar
- 4.A. Zeilinger. in New Techniques an Ideas in Quantum Mechanics, p. 164, edited by ( New York Acad. Science, New York, 1986 ).Google Scholar
- 5.T. Sleator, O. Carnal, T. Pfau, A. Faulstich, H. Takuma and J. Mlynek. in Laser Spectroscopy X, p. 264, edited by M. Dulcoy, E. Giacobino and G. Camy ( World Scientific, Singapore, 1991 ).Google Scholar
- M.S. Chapman, C.R. Ekstrom, T.D. Hammond, R.A. Rubenstein, J. Schmiedmayer, S. Wehinger and D.E. Pritchard, in press.Google Scholar
- 9.C. Bordé, Phys. Lett. A 140, 10 (1989)Google Scholar
- 10.P. Storey and C. Cohen-Tannoudji, J. Phys. II France 4, 1999 (1994)Google Scholar
- 16.Because of the narrow acceptance of the detector for this correlation experiment, C(laser on) # C(laser oft) even when d = 0.Google Scholar
- 17.N.F. Ramsey. Molecular Beams (Oxford University Press, Oxford, 1985 )Google Scholar