Particle on the sphere: group-theoretic quantization in the presence of a magnetic monopole
Particle on the sphere: group-theoretic quantization in the presence of a magnetic monopole
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DOI:
10.1088/1751-8121/abf961
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发表时间:
2020-11
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通讯作者:
Rodrigo Andrade e Silva;T. Jacobson
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文献类型:
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作者:
Rodrigo Andrade e Silva;T. Jacobson
The problem of quantizing a particle on a two-sphere has been treated by numerous approaches, including Isham’s global method based on unitary representations of a symplectic symmetry group that acts transitively on the phase space. Here we reconsider this simple model using Isham’s scheme, enriched by a magnetic flux through the sphere via a modification of the symplectic form. To maintain complete generality we construct the Hilbert space directly from the symmetry algebra, which is manifestly gauge-invariant, using ladder operators. In this way, we recover algebraically the complete classification of quantizations, and the corresponding energy spectra for the particle. The famous Dirac quantization condition for the monopole charge follows from the requirement that the classical and quantum Casimir invariants match. In an appendix we explain the relation between this approach and the more common one that assumes from the outset a Hilbert space of wave functions that are sections of a nontrivial line bundle over the sphere, and show how the Casimir invariants of the algebra determine the bundle topology.