Symmetries and conservation laws in histories-based theories

Abstract

Symmetries are defined in histories-based theories paying special attention to the class of history theories admitting quasitemporal structure (a generalization of the concept of `temporal sequences' of `events' using partial semigroups) and logic structure for `single-time histories'. Symmetries are classified into orthochronous (those preserving the `temporal order' of `events') and nonorthochronous. A straightforward criterion for physical equivalence of histories is formulated in terms of orthochronous symmetries; this criterion covers various notions of physical equivalence of histories considered by Gell-Mann and Hartle as special cases. In familiar situations, a reciprocal relationship between traditional symmetries (Wigner symmetries in quantum mechanics and Borel-measurable transformations of phase space in classical mechanics) and symmetries defined in this work is established. In a restricted class of theories, a definition of conservation law is given in the history language which agrees with the standard ones in familiar situations; in a smaller subclass of theories, a Noether type theorem (implying a connection between continuous symmetries of dynamics and conservation laws) is proved. The formalism evolved is applied to histories (of particles, fields or more general objects) in general curved spacetimes. Sharpening the definition of symmetry so as to include a continuity requirement, it is shown that a symmetry in our formalism implies a conformal isometry of the spacetime metric.

54 pages. Accepted for publication in Annals of Physics. Several typos corrected. This paper is a combined version of gr-qc/9812018 and gr-qc/9905028 with several modifications

References in corpus (8)

• Quantum Logic and the Histories Approach to Quantum Theory
• Quantum temporal logic and decoherence functionals in the histories approach to generalised quantum theory
• Continuous Histories and the History Group in Generalised Quantum Theory
• The Classification of Decoherence Functionals: An Analogue of Gleason's Theorem
• Conservation Laws in the Quantum Mechanics of Closed Systems
• Symmetries of Decoherence Functionals
• Symmetry and History Quantum Theory: An analogue of Wigner's Theorem
• Completeness of Decoherence Functionals