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arXiv · 2208.14997

A single-particle framework for unitary lattice gauge theory in discrete time

Pablo Arnault·Christopher Cedzich
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Abstract

We construct a real-time lattice-gauge-theory-type action for a spin-1/2 matter field of a single particle on a (1+1)-dimensional spacetime lattice. The framework is based on a discrete-time quantum walk, and is hence inherently unitary and strictly local, i.e., transition amplitudes exactly vanish outside of a lightcone on the lattice. We then provide a lattice Noether's theorem for internal symmetries of this action. We further couple this action to an electromagnetic field by a minimal substitution on the lattice. Finally, we suggest a real-time lattice-gauge-theory-type action for the electromagnetic field in arbitrary spacetime dimensions, and derive its classical equations of motion, which are lattice versions of Maxwell's equations.

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Pablo Arnault, Christopher Cedzich. 2022-08-31. A single-particle framework for unitary lattice gauge theory in discrete time. https://doi.org/10.1088/1367-2630%2Facac47

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