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arXiv:1504.01788

Discrete Phase Space: Quantum mechanics and non-singular potential functions

Anadijiban Das, Andrew DeBenedictis

Published Apr 8, 2015• 0 citations
arXivHTMLPDF

Abstract

The three-dimensional potential equation, motivated by representations of quantum mechanics, is investigated in four different scenarios: (i) In the usual Euclidean space $\mathbb{E}_{3}$ where the potential is singular but invariant under the continuous inhomogeneous orthogonal group $\mathcal{I}O(3)$. The invariance under the translation subgroup is compared to the corresponding unitary transformation in the Schrödinger representation of quantum mechanics. This scenario is well known but serves as a reference point for the other scenarios. (ii) Next, the discrete potential equation as a partial difference equation in a three-dimensional lattice space is studied. In this arena the potential is non-singular but invariance under $\mathcal{I}O(3)$ is broken. This is the usual picture of lattice theories and numerical approximations. (iii) Next we study the six-dimensional continuous phase space. Here a phase space representation of quantum mechanics is utilized. The resulting potential is singular but possesses invariance under $\mathcal{I}O(3)$. (iv) Finally, the potential is derived from the discrete phase space representation of quantum mechanics, which is shown to be an \emph{exact} representation of quantum mechanics. The potential function here is both non-singular and possesses invariance under $\mathcal{I}O(3)$, and this is proved via the unitary transformations of quantum mechanics in this representation.

DOI
10.48550/arxiv.1504.01788

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The three-dimensional potential equation, motivated by representations of quantum mechanics, is investigated in four different scenarios: (i) In the usual Euclidean space E3\mathbb{E}_{3}E3​ where the potential is singular but invariant under the continuous inhomogeneous orthogonal group IO(3)\mathcal{I}O(3)IO(3). The invariance under the translation subgroup is compared to the corresponding unitary transformation in the Schrödinger representation of quantum mechanics. This scenario is well known but serves as a reference point for the other scenarios. (ii) Next, the discrete potential equation as a partial difference equation in a three-dimensional lattice space is studied. In this arena the potential is non-singular but invariance under IO(3)\mathcal{I}O(3)IO(3) is broken. This is the usual picture of lattice theories and numerical approximations. (iii) Next we study the six-dimensional continuous phase space. Here a phase space representation of quantum mechanics is utilized. The resulting potential is singular but possesses invariance under IO(3)\mathcal{I}O(3)IO(3). (iv) Finally, the potential is derived from the discrete phase space representation of quantum mechanics, which is shown to be an \emph{exact} representation of quantum mechanics. The potential function here is both non-singular and possesses invariance under IO(3)\mathcal{I}O(3)IO(3), and this is proved via the unitary transformations of quantum mechanics in this representation.
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