Dynamic and static properties of Quantum Hall and Harmonic Oscillator systems on the non-commutative plane

TL;DR

This paper investigates the properties of quantum systems on the non-commutative plane, clarifying gauge transformations in the Landau problem, correcting previous assumptions about the symmetric gauge, and analyzing the dynamics of the harmonic oscillator.

Contribution

It provides a gauge transformation framework for the Landau problem in noncommutative space and corrects the form of the symmetric gauge, also exploring the non-commutative harmonic oscillator dynamics.

Findings

Corrected the form of the symmetric gauge in noncommutative space.

Established the relation between magnetic field and gauge parameters.

Found quasi-periodic behavior in non-commutative harmonic oscillator dynamics.

Abstract

We study two quantum mechanical systems on the noncommutative plane using a representation independent approach. First, in the context of the Landau problem, we obtain an explicit expression for the gauge transformation that connects the Landau and the symmetric gauge in noncommutative space. This lead us to conclude that the usual form of the symmetric gauge $\vec{A}=\left(-\frac{\beta}{2}\hat{Y},\frac{\beta}{2}\hat{X}\right)$, in which the constant $\beta$ is interpreted as the magnetic field, is not true in noncommutative space. We also be able to establish a precise definition of $\beta$ as function of the magnetic field, for which the equivalence between the symmetric and Landau gauges is hold in noncommutative plane. Using the symmetric gauge we obtain results for the spectrum of the Quantum Hall system, its transverse conductivity in the presence of an electric field and other static observables. These results amend the literature on Quantum Hall Effect in noncommutative plane in which the incorrect form of the symmetric gauge, in noncommutative space, is assumed. We also study the non-equilibrium dynamics of simple observables for this system. On the other hand, we study the dynamics of the harmonic oscillator in non-commutative space and show that, in general, it exhibit quasi-periodic behavior, in striking contrast with its commutative version. The study of the dynamics reveals itself as a most powerful tool to characterize and understand the effects of non-commutativity.