How are units of measure defined in Quantum Mechanics?

[Stephen Tashi]

In classical physics, the definition of a unit of measure involves a deterministic process (e.g. "the amount of force necessary to give a kilogram mass the acceleration of 1 meter per second square"). How are such units defined in Quantum Mechanics?

( Do we replace references to quantities with references to their expected values? )

 

[Vanadium 50]

Units are defined the same. The universe is fundamentally quantum, but that doesn't stop us from defining (e.g.) the kilogram.