Quantization in Polar Coordinates and the Phase Operator
Author(s) -
D. A. Dubin,
Mark A. Hennings,
Thomas Smith
Publication year - 1994
Publication title -
publications of the research institute for mathematical sciences
Language(s) - English
Resource type - Journals
eISSN - 1663-4926
pISSN - 0034-5318
DOI - 10.2977/prims/1195165908
Subject(s) - mathematics , polar , polar coordinate system , log polar coordinates , operator (biology) , quantization (signal processing) , generalized coordinates , mathematical analysis , geometry , physics , algorithm , chemistry , quantum mechanics , biochemistry , repressor , transcription factor , gene
We review some of the difficulties previously encountered in defining the phase operator for finite quantum systems. We then propose the Wigner-Weyl quantization of the angle function q> on phase space as the phase operator, and derive a closed expression for its matrix elements with respect to the Hermite functions. We also determine the quantization of el, which turns out to be a weighted shift operator, its spectrum and that of its adjoint. This is done in the framework of quantization of a certain symbol class of phase space distributions, specialized to those which depend on one variable only. After recalling some results for the position and momentum variables, we apply the scheme to functions of radius or angle. We give necessary and sufficient conditions for operators obtained by quantizing functions of the angle to be elements of ^ + [^(R)] and ^+ [^(R), L2(R)], and a sufficient condition for boundedness. We then consider the associated questions of commutation relations and uncertainties for operators in J^ + [5^(R), L2(R)], which we define as bilinear forms. As must be the case, the commutator between our phase operator and the number operator exhibits noncanonical terms. Not surprisingly, the Poisson bracket of their phase space symbols also exhibits a noncanonical term.
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