On obtaining classical mechanics from quantum mechanics

dc.creatorDate, Ghanashyam
dc.date2006-06-18
dc.date2006-12-04
dc.date.accessioned2026-07-07T10:24:21Z
dc.date.available2026-07-07T10:24:21Z
dc.descriptionConstructing a classical mechanical system associated with a given quantum mechanical one, entails construction of a classical phase space and a corresponding Hamiltonian function from the available quantum structures and a notion of coarser observations. The Hilbert space of any quantum mechanical system naturally has the structure of an infinite dimensional symplectic manifold (`quantum phase space'). There is also a systematic, quotienting procedure which imparts a bundle structure to the quantum phase space and extracts a classical phase space as the base space. This works straight forwardly when the Hilbert space carries weakly continuous representation of the Heisenberg group and recovers the linear classical phase space $\mathbb{R}^{\mathrm{2N}}$. We report on how the procedure also allows extraction of non-linear classical phase spaces and illustrate it for Hilbert spaces being finite dimensional (spin-j systems), infinite dimensional but separable (particle on a circle) and infinite dimensional but non-separable (Polymer quantization). To construct a corresponding classical dynamics, one needs to choose a suitable section and identify an effective Hamiltonian. The effective dynamics mirrors the quantum dynamics provided the section satisfies conditions of semiclassicality and tangentiality.
dc.descriptionrevtex4, 24 pages, no figures. In the version 2 certain technical errors in section I-B are corrected, the part on WKB (and section II-B) is removed, discussion of dynamics and semiclassicality is extended and references are added. Accepted for publication on Classical and Quantum Gravity
dc.identifierhttps://arxiv.org/abs/gr-qc/0606078
dc.identifierhttp://arxiv.org/abs/gr-qc/0606078
dc.identifierClass.Quant.Grav.24:535-550,2007
dc.identifierdoi:10.1088/0264-9381/24/3/002
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/176154
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectHigh Energy Physics - Theory
dc.subjectMathematical Physics
dc.subjectQuantum Physics
dc.titleOn obtaining classical mechanics from quantum mechanics
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