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arXiv · 1308.5599

Why Gauge?

Carlo Rovelli
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Abstract

The world appears to be well described by gauge theories; why? I suggest that gauge is more than mathematical redundancy. Gauge-dependent quantities can not be predicted, but there is a sense in which they can be measured. They describe "handles" though which systems couple: they represent real relational structures to which the experimentalist has access in measurement by supplying one of the relata in the measurement procedure itself. This observation leads to a physical interpretation for the ubiquity of gauge: it is a consequence of a relational structure of physical quantities.

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Carlo Rovelli. 2013-08-26. Why Gauge?. https://doi.org/10.1007/s10701-013-9768-7

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