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An Optimal Transport View of Schrödinger's Equation

Published online by Cambridge University Press:  20 November 2018

Max-K. von Renesse*
Affiliation:
Technische Universität Berline-mail: mrenesse@math.tu-berlin.de
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Abstract

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We show that the Schrödinger equation is a lift of Newton's third law of motion $\nabla _{{\dot{\mu }}}^{\mathcal{W}}\,\dot{\mu }\,=\,-{{\nabla }^{\mathcal{W}}}\,F\left( \mu \right)$ on the space of probability measures, where derivatives are taken with respect to the Wasserstein Riemannian metric. Here the potential $\mu \,\to \,F\left( \mu \right)$ is the sum of the total classical potential energy $\left\langle V,\,\mu \right\rangle $ of the extended system and its Fisher information $\frac{{{\hbar }^{2}}}{8}\,{{\int{\left| \nabla \,\text{1n}\,\mu \right|}}^{2}}\,d\mu $. The precise relation is established via a well-known (Madelung) transform which is shown to be a symplectic submersion of the standard symplectic structure of complex valued functions into the canonical symplectic space over the Wasserstein space. All computations are conducted in the framework of Otto's formal Riemannian calculus for optimal transportation of probability measures.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2012

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