The Quantum-Mechanical Position Operator in Extended Systems
Materials Science
2009-10-30 v1 Strongly Correlated Electrons
Quantum Physics
Abstract
The position operator (defined within the Schroedinger representation in the standard way) becomes meaningless when periodic boundary conditions are adopted for the wavefunction, as usual in condensed matter physics. We show how to define the position expectation value by means of a simple many-body operator acting on the wavefunction of the extended system. The relationships of the present findings to the Berry-phase theory of polarization are discussed.
Cite
@article{arxiv.cond-mat/9709306,
title = {The Quantum-Mechanical Position Operator in Extended Systems},
author = {R. Resta},
journal= {arXiv preprint arXiv:cond-mat/9709306},
year = {2009}
}
Comments
Four pages in RevTeX