Entanglement, Decoherence and the Quantum/Classical Boundary
DOI: 10.1063/1.882326
Quantum mechanics is very puzzling. A particle can be delocalized, it can be simultaneously in several energy states and it can even have several different identities at once. This schizophrenic behavior is encoded in its wavefunction, which can always be written as a superposition of quantum states, each characterized by a complex probability amplitude. Interferences between these amplitudes occur when the particle can follow several indistinguishable paths. Any attempt to determine which trajectory it “actually takes” destroys these interferences. This is a manifestation of wave—particle complementarity, which has recently been illustrated in textbook fashion by several beautiful experiments.
References
1. T. Pfau, S. Spalter, C. Kurtsiefer, C. Ekstrom, J. Mlynek, Phys. Rev. Lett. 73, 1223 (1994).
M. Chapman, T. Hammond, A. Lenef, J. Schiedmeyer, R. Rubinstein, E. Smith, D. Pritchard, Phys. Rev. Lett. 75, 3783 (1995).https://doi.org/PRLTAO2. A. Einstein, B. Podolsky, N. Rosen, Phys. Rev. 47, 477 (1935).https://doi.org/PHRVAO
3. J. Clauser, Phys. Rev. Lett. 36, 1223 (1976).
S. Fry, R. Thompson, Phys. Rev. Lett. 37, 465 (1976).
A. Aspect, P. Grangier, G. Roger, Phys. Rev. Lett. 49, 91 (1982). https://doi.org/PRLTAO
A. Aspect, J. Dalibard, G. Roger, Phys. Rev. Lett. 49, 1804 (1982). https://doi.org/PRLTAO
Z. Ou, L. Mandel, Phys. Rev. Lett. 61, 50 (1988). https://doi.org/PRLTAO
P. Kwiat, K. Mattle, H. Weinfurter, A. Zeilinger, Phys. Rev. Lett. 75, 4337 (1995). https://doi.org/PRLTAO
W. Tittel et al., Phys. Rev. A 57, 3229 (1998).4. E. Schrodinger, Naturwissenschaften 23, 807, 823and 844 (1935), reprinted in English in ref. 12.
5. See D. Giulini, E. Joos, C. Kiefer, J. Kupsch, I. Stamatescu, H. D. Zeh, Decoherence and the Appearance of a Classical World in Quantum Theory, Springer, New York (1996).
6. A. Leggett, in Chance and Matter, Proc. Les Houches Summer School XLVI, J. Souletie, J. Vannimenus, R. Stora, eds., North Holland, Amsterdam (1987).
7. E. Jaynes, F. Cummings, Proc. IEEE 51, 89 (1963).
L. Allen, J. Eberly, Optical. Resonance and Two‐Level Atoms, Wiley, New York (1975).8. B. Yurke, D. Stoler, Phys. Rev. Lett. 57, 13 (1986).
J. Gea‐Banacloche, Phys. Rev. A, 44, 5913 (1991).
V. Buzek, H. Moya‐Cessa, P. Knight, Phys. Rev. A 45, 8190 (1992).
C. Savage, S. Braunstein, D. Walls, Opt. Lett. 15, 628 (1990).https://doi.org/OPLEDP9. C. Monroe, D. Meekhof, B. King, D. Wineland, Science, 272, 1131 (1996).
10. M. Brune, E. Hagley, J. Dreyer, X. Maítre, A. Maali, C. Wunderlich, J. Raimond, S. Haroche, Phys. Rev. Lett. 77, 4887 (1996).https://doi.org/PRLTAO
11. L. Davidovich, M. Brune, J. Raimond, S. Haroche, Phys. Rev. A 53, 1295 (1996).https://doi.org/PLRAAN
12. J. A. Wheeler, W. Zurek, Quantum Theory of Measurement, Princeton U.P., Princeton, N.J. (1983).
13. See, for example, G. Ghirardi, A. Rimini, T. Weber, Phys. Rev. D 34, 470 (1986).https://doi.org/PRVDAQ
14. A. Ekert, R. Josza, Rev. Mod. Phys. 68, 733 (1996).https://doi.org/RMPHAT
15. J. Cirac, P. Zoller, Phys. Rev. Lett. 74, 4091 (1995). https://doi.org/PRLTAO
C. Monroe, D. Meekhof, B. King, W. Itano, D. Wineland, Phys. Rev. Lett. 75, 4714 (1995).16. P. Domokos, J. Raimond, M. Brune, S. Haroche, Phys. Rev. A 52, 3554 (1995). https://doi.org/PLRAAN
X. Maitre, E. Hagley, G. Nogues, C. Wunderlich, P. Goy, M. Brune, J. Raimond, S. Haroche, Phys. Rev. Lett. 79, 769 (1997). https://doi.org/PRLTAO
Q. Turchette, C. Hood, W. Lange, H. Mabuchi, H. Kimble, Phys. Rev. Lett. 75, 4710 (1995).https://doi.org/PRLTAO17. E. Hagley, X. Maitre, G. Nogues, C. Wunderlich, M. Brune, J. Raimond, S. Haroche, Phys. Rev. Lett. 79, 1 (1997).
18. D. Bouwmeester, J. W. Pan, K. Mattle, M. Eibl, H. Weinfurter, A. Zeilinger, Nature 390, 575 (1997). https://doi.org/NATUAS
D. Boschi, S. Branca, F. De Martini, L. Hardy, S. Popescu, Phys. Rev. Lett. 80, 1121 (1998).
More about the Authors
Serge Haroche. Ecole Normale Supérieure, Paris.
