Observing a schrödinger cat

Foundations of Physics Letters

Volumn 11, Issue 3, 1998, Pages 209-231

  Placek, Tomasz ^a  

^a JAGIELLONIAN UNIVERSITY   (Poland)

Author keywords

Decoherence; Measurement problem; Quantum mechanics

Indexed keywords

EID: 0347802048     PISSN: 08949875     EISSN: None     Source Type: Journal    
DOI: 10.1023/A:1022486008545     Document Type: Article

References (22)

1. M. Brune, E. Hagley, J. Dreyer, X. Maître , A. Maali, C. Wunderlich, J. M. Raimond, and S. Haroche, Phys. Rev. Lett. 77, 4887 (1996).
2. This is not the only experiment in which a Schrödinger cat-like state has been observed. Other important work in this area is reported in: C. Monroe, D. M. Meekof, B. C. King, and D. J. Wineland, Science 272, 1131 (1996).
3. I follow here the standard convention that an observable is denoted by a capital letter, while the operator that represents it -the letter with a hat.
4. B. d'Espagnat, Conceptual Foundations of Quantum Mechanics (Benjamin, Menlo Park, 1971), p. 214. I have substituted M in the quote, where d'Espagnat uses A.
5. E. Schrödinger, Die Naturwissenschaften 23, 807-12, 823-808, 844-9 (1935).
6. For a distinction between proper and improper mixtures, see for instance: B. d'Espagnat, Conceptual Foundations of Quantum Mechanics (Benjamin, Reading, Mass., 1976) pp. 58-59.
7. For a discussion of requirements an observable needs to satisfy to distinguish between W′ and W″ see, e.g., M. Redhead, Incompleteness, Nonlocality and Realism (Clarendon, Oxford, 1987), pp. 54-57.
8. The evolution is non-unitary if it is governed by a non-unitary operator. It is non-causal if a later state of a system is not determined, in a functional sense, by its earlier states.
9. A. O. Caldeira and A. J. Leggett, Physica A 121, 587 (1983). E. Joos and H. D. Zeh, Z. Phys. B 59, 223 (1985). W. Żurek, Phys. Rev. D 24, 1516 (1981); 26, 1862 (1982); Physics Today 44, 10, 36 (1991).
10. A. O. Caldeira and A. J. Leggett, Physica A 121, 587 (1983). E. Joos and H. D. Zeh, Z. Phys. B 59, 223 (1985). W. Żurek, Phys. Rev. D 24, 1516 (1981); 26, 1862 (1982); Physics Today 44, 10, 36 (1991).
11. A. O. Caldeira and A. J. Leggett, Physica A 121, 587 (1983). E. Joos and H. D. Zeh, Z. Phys. B 59, 223 (1985). W. Żurek, Phys. Rev. D 24, 1516 (1981); 26, 1862 (1982); Physics Today 44, 10, 36 (1991).
12. A. O. Caldeira and A. J. Leggett, Physica A 121, 587 (1983). E. Joos and H. D. Zeh, Z. Phys. B 59, 223 (1985). W. Żurek, Phys. Rev. D 24, 1516 (1981); 26, 1862 (1982); Physics Today 44, 10, 36 (1991).
13. A. O. Caldeira and A. J. Leggett, Physica A 121, 587 (1983). E. Joos and H. D. Zeh, Z. Phys. B 59, 223 (1985). W. Żurek, Phys. Rev. D 24, 1516 (1981); 26, 1862 (1982); Physics Today 44, 10, 36 (1991).
14. A highly recommended assessment of the decoherence approach is F. Dowker and A. Kent, J. Stat. Phys., 82, 5/6, 1575 (1996).
15. For an argument, see, e.g., B. d'Espagnat, Conceptual Foundations of Quantum Mechanics (Benjamin, Reading, Mass., 1976), pp. 58-62.
16. I am indebted to an anonymous referee for obtaining clarity about this matter.
17. R. Omnès, The Interpretation of Quantum Mechanics (Princeton University Press, Princeton, 1994), pp. 306-311.
18. L. Davidovich, M. Brune, J. M. Raimond and S. Haroche, Phys Rev. A 53 (3), 1295 (1996).
19. R. J. Glauber, Phys. Rev. 131 (6), 2766-2778 (1963).
20. For a circular state, the magnetic number m and the principal quantum number n should satisfy \m\ = n - 1; such states have particularly long radiative lifetimes and are highly resonant with the field. See: R. G. Hulet and D. Kleppner, Phys. Rev. Lett. 51, 16 (1983).
21. An interested reader may also consult J. Perina, Quantum Statistics of Linear and Non-Linear Optical Phenomena (Reidel, Dordrecht, 1984).
22. I am indebted for this point to an anonymous referee.