Duality and the geometry of quantum mechanics

Abstract

A recent notion in theoretical physics is that not all quantum theories arise from quantizing a classical system. Also, a given quantum model may possess more than just one classical limit. There is strong evidence for these facts in string duality and M-theory, and it has been suggested that they should also have a counterpart in quantum mechanics. In view of these developments we propose dequantization, a mechanism to render a quantum theory classical. Specifically, we present a geometric procedure to dequantize a given quantum mechanics (regardless of its classical origin, if any) to possibly different classical limits, whose quantization gives back the original quantum theory. The standard classical limit →0 arises as a particular case of our approach.