Abstract
The notion of coexistence of quantum observables was introduced to describe the possibility of measuring two or more observables together. Here we survey the various different formalisations of this notion and their connections. We review examples illustrating the necessary degrees of unsharpness for two noncommuting observables to be jointly measurable (in one sense of the phrase). We demonstrate the possibility of measuring together (in another sense of the phrase) noncoexistent observables. This leads us to a reconsideration of the connection between joint measurability and noncommutativity of observables and of the statistical and individual aspects of quantum measurements.
Similar content being viewed by others
References
Ali, S. T.— Prugovečki, E.: Classical and quantum statistical mechanics in a common Liouville space, Phys. A 89 (1977), 501–521.
Berg, C.— Christensen, J.— Ressel, P.: Harmonic Analysis on Semigroups, Springer, New York, 1984.
Billingsley, P.: Probability and Measure (2nd ed.), John Wiley & Sons, New York, 1986.
Busch, P.: Unbestimmtheitsrelation und simultane Messungen in der Quantentheorie. PhD. Thesis, University of Cologne, Cologne, 1982 [English translation: Indeterminacy relations and simultaneous measurements in quantum theory, Internat. J. Theoret. Phys. 24 (1985), 63–92].
Busch, P.: Unsharp reality and joint measurements for spin observables, Phys. Rev. D (3) 33 (1986), 2253–2261.
Busch, P.: Some realizable joint measurements of complementary observables, Found. Phys. 27 (1987), 905–937.
Busch, P.: On the sharpness and bias of quantum effects, Found. Phys. 39 (2009), 712–730. arXiv:0706.3532v2.
Busch, P.— Grabowski, M.— Lahti, P. J.: Operational Quantum Physics. Lect. Notes Phys. Monogr., Springer, Berlin, 1995.
Busch, P.— Heinonen, T.— Lahti, P.: Heisenberg’s uncertainty principle, Phys. Rep. 452 (2007), 155–176.
Busch, P.— Kiukas, J.— Lahti, P.: Measuring position and momentum together, Phys. Lett. A 372 (2008), 4379–4380.
Busch, P.— Schmidt, H. J.: Coexistence of qubit effects, Quantum Inf. Process 9 (2010), 143–169. arXiv:0802.4167.
Carmeli, C.— Heinonen, T.— Toigo, A.: Position and momentum observables on ℝ and ℝ3, J. Math. Phys. 45 (2004), 2526–2539.
Dvurečenskij, A.— Lahti, P.— Pulmannová, S.— Ylinen, K.: Notes on coarse grainings and functions of observables, Rep. Math. Phys. 55 (2005), 241–248.
Heinonen, T. — LAHTI, P. — PELLONPÄÄ, J. P. — PULMANNOVÁ, S. — YLINEN, K.: The norm-1 property of a quantum observable, J. Math. Phys. 44 (2003), 1998–2008.
Heinosaari, T.— Reitzner, D.— Stano, P.: Notes on joint measurability of quantum observables, Found. Phys. 38 (2008), 1133–1147.
Kiukas, J.— Lahti, P.: A note on the measurement of phase space observables with an eight-port homodyne detector, J. Modern Opt. 55 (2008), 1891–1898.
Kiukas, J.— Lahti, P.— Pellonpää, J. P.: A proof for the informational completeness for the rotated quadrature observables, J. Phys. A.Math. Theor. 41 (2008), 175206.
Kiukas, J.— Lahti, P.— Schultz, J.: Position and momentum tomography, Phys. Rev. A (3) 79 (2009), 052119.
Kiukas, J.— Lahti, P.— Ylinen, K.: Semispectral measures as convolutions and their moment operators, J. Math. Phys. 49 (2008), 112103/6.
Kiukas, J.— Werner, R.: Private communication, 2008.
Lahti, P.— Pulmannová, S.: Coexistent observables and effects in quantum mechanics, Rep. Math. Phys. 39 (1997), 339–351.
Lahti, P.— Pulmannová, S.: Coexistent vs. functional coexistence of quantum observables, Rep. Math. Phys. 47 (2001), 199–212.
Lahti, P.— Pulmannová, S.— Ylinen, K.: Coexistent observables and effects in convexity approach, J. Math. Phys. 39 (1998), 6364–6371.
Lahti, P.— Ylinen, K.: Dilations of positive operator measures and bimeasures related to quantum mechanics, Math. Slovaca 54 (2004), 169–189.
Leonhardt, U.— Paul, H.— D’Ariano, G. M.: Tomographic reconstruction of the density matrix via pattern functions, Phys. Rev. A (3) 52 (1995), 4899–4898.
Ludwig, G.: Foundations of Quantum Mechanics I, Springer, Berlin, 1983.
Martens, H.— De Muynck, W. M.: Nonideal quantum measurements, Found. Phys. 20 (1990), 255–281.
Miyadera, T.— Imai, H.: Heisenberg’s uncertainty principle for simultaneous measurement of positive-operator-valued measures, Phys. Rev. A (3) 78 (2008), 052119.
Moreland, T.— Gudder, S.: Infima of Hilbert space effects, Linear Algebra Appl. 286 (1999), 1–17.
Pták, P.— Pulmannová, S.: Orthomodular Structures as Quantum Logics. Kluwer Acad. Publ., Dordrecht, 1991.
Raymer, M. G.: Uncertainty principle for joint measurement of noncommuting variables, Amer. J. Phys. 62 (1994), 986–993.
Sikorski, R.: Boolean Algebras, Springer, Berlin, 1964.
Simon, B.: The classical moment problem as a self-adjoint finite difference operator, Adv. Math. 137 (1998), 82–203.
Stano, P.— Reitzner, D.— Heinosaari, T.: Coexistence of qubit effects, Phys. Rev. A (3) 78 (2008), 012315.
Törmä, P.— Stenholm, S.— Jex, I.: Measurement and preparation using two probe modes, Phys. Rev. A (3) 52 (1995), 4812–4822.
Varadarajan, V. S.: Geometry of Quantum Theory, Springer, Berlin, 1985 (First edition by van Nostrand, Princeton, 1968, 1970).
Von Weizsäcker, C. F.: Quantum theory and space-time. In: Symposium on the Foundations of Modern Physics (P. Lahti, P. Mittelstaed, eds.), World Scientific Publishing Co., Singapore, 1985, pp. 223–237.
Werner, R.: The uncertainty relation for joint measurement of position and momentum, Quantum Inf. Comput. 4 (2004), 546–562.
Yu, S.— Liu, N. L.— Li, L.— Oh, C. H.: Joint measurement of two unsharp observables of a qubit. arXiv:0805.1538 (2008).
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Anatolij Dvurečenskij
Dedicated to Professor Sylvia Pulmannová on the occasion of her 70th birthday
About this article
Cite this article
Busch, P., Kiukas, J. & Lahti, P. On the notion of coexistence in quantum mechanics. Math. Slovaca 60, 665–680 (2010). https://doi.org/10.2478/s12175-010-0039-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.2478/s12175-010-0039-1