Oxford University Press eBooks

Operators and observables

Peter Joshua Atkins, Julio de Paula, James Keeler

Published Dec 5, 2022• 1 citation

Abstract

This chapter explains that a central feature of quantum theory is its representation of observables by ‘operators’, which act on the wavefunction and extract the information it contains. It shows how operators are constructed and used. Observables are represented by hermitian operators, which have real eigenvalues and orthogonal eigenfunctions. When the system is not described by a single eigenfunction of an operator, it may be expressed as a superposition of such eigenfunctions. One consequence of the use of operators is the ‘uncertainty principle’, one of the most profound departures of quantum mechanics from classical mechanics. The uncertainty principle restricts the precision with which complementary observables may be specified and measured simultaneously.

DOI: 10.1093/hesc/9780198847816.003.0035

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