Introductory Abstract
We explore the sense in which the state of a physical system may or may not be regarded (an) observable in quantum mechanics. Simple and general arguments from various lines of approach are reviewed which demonstrate the following no-go claims: (1) the structure of quantum mechanics precludes the determination of the state of a single system by means of measurements performed on that system only; (2) there is no way of using entangled two-particle states to transmit superluminal signals. Employing the representation of observables as general positive operator valued measures, our analysis allows one to indicate whether optimal separation of different states is achieved by means of sharp or unsharp observables.
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Notes and References
N. Herbert, Found. Phys. 12, 1171 (1982).
D. Dieks, Phys. Lett. 92A, 271 (1982).
P. Eberhard, Nuovo Cim. 46B, 392 (1978).
G.C. Ghirardi, A. Rimini, T. Weber, Lett. Nuovo Cim. 27, 293 (1980).
R.J. Glauber, in New Techniques and Ideas in Quantum Measurement Theory,ed. D.M. Greenberger, The New York Academy of Sciences, New York, 1986, pp. 336–372, esp. p. 362ff.
L. Mandel, Nature 304, 188 (1983).
W.K. Wootters, W.H. Zurek, Nature 299, 802 (1982).
The question of the peaceful coexistence of quantum mechanics and relativity has been reviewed by A. Shimony, in S. Kamefuchi et al. (eds.), Foundations of Quantum Mechanics in the Light of New Technology,Tokyo: The Physical Society of Japan, 1984.
A formulation of the no-signaling proof that comprises general amplification and cloning procedures is given in H. Scherer, P. Busch, Phys. Rev. 47, 1647 (1993).
A. Peres, Quantum Theory: Concepts and Methods, Kluwer Academic Publishers, Dordrecht, 1993, Chapter 9.
M.G. Alford, S. Coleman, J. March-Russell, Nuclear Physics B351, 735 (1991).
I.D. Ivanovic, Phys. Lett. A 123, 257 (1987).
D. Dieks, Phys. Leu. A 126, 303 (1988).
A. Peres, Phys. Lett. A. 128, 19 (1988).
G. Jaeger, A. Shimony, Phys. Lett. A 197, 83 (1995).
A. Royer, Phys. Rev. Lett. 73, 913 (1994); Erratum: ibid., February (1995).
We prove the following mathematical fact which will be used in several instances throughout this paper: for an operator E with 0 (t IE) 1 for all states 1, the relation (gyp 4) = 1, resp. (1/i4E1/i) = 0 (for states v, 1 r) is equivalent to Ev = ço, resp. Et/,= 0. The latter equations are obviously sufficient for the former. Their necessity follows from the observation that (gyp IEt;) = INM) = II~III2.
P. Busch, M. Grabowski, P. Lahti, Operational Quantum Physics, Springer-Verlag, Berlin, 1995.
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Busch, P. (1997). Is the Quantum State (an) Observable?. In: Cohen, R.S., Horne, M., Stachel, J. (eds) Potentiality, Entanglement and Passion-at-a-Distance. Boston Studies in the Philosophy of Science, vol 194. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-2732-7_5
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DOI: https://doi.org/10.1007/978-94-017-2732-7_5
Publisher Name: Springer, Dordrecht
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