Canonical quantization on the half-line and in an interval based upon an alternative concept for the momentum in a space with boundaries

Al-Hashimi, M. H.; Wiese, Uwe-Jens

doi:10.48350/162001

Canonical quantization on the half-line and in an interval based upon an alternative concept for the momentum in a space with boundaries

DOI

10.48350/162001

Publisher DOI

10.1103/PhysRevResearch.3.033079

Abstract

For a particle moving on a half-line or in an interval the operator pˆ = −i∂x is not self-adjoint and thus does not qualify as the physical momentum. Consequently canonical quantization based on pˆ fails. Based upon an alternative concept for a self-adjoint momentum operator pˆR, we show that canonical quantization can indeed be implemented on the half-line and on an interval. Both the Hamiltonian Hˆ and the momentum operator pˆR are endowed with self-adjoint extension parameters that characterize the corresponding domains D(Hˆ ) and D(pˆR ) in the Hilbert space. When one replaces Poisson brackets by commutators, one obtains meaningful results only if the corresponding operator domains are properly taken into account. The alternative concept for the momentum is used to describe the results of momentum measurements of a quantum mechanical particle that is reflected at impenetrable boundaries, either at the end of the half-line or at the two ends of an interval.

Date Issued

2021-07-21

Publication Type

Article

Subject(s)

500 Science > 530 Physics

Language(s)

en

Author(s)