We'd like to use analytics cookies to understand which symbols people look up, so we know what to research next. They are not used for advertising and we set none of them unless you say yes. What we store.
Square brackets around two operators separated by a comma.
Also known as: Commutator, Square bracket commutator, Operator commutator
The commutator measures how much two operations fail to commute: AB minus BA. In quantum mechanics a non-zero commutator is exactly what makes two quantities impossible to measure together, so the bracket is where the uncertainty principle actually lives.
Denotes the commutator of two operators or group elements: the extent to which their order matters.
Contexts: Mathematics
Is zero precisely when the two commute, which in quantum mechanics is the condition for two observables to be simultaneously measurable.
Contexts: Mathematics
Is defined multiplicatively in group theory — the element g⁻¹h⁻¹gh — rather than additively as in operator algebra; the same bracket serves both.
Contexts: Mathematics
A pair of square brackets with straight vertical sides and short horizontal returns, enclosing two names separated by a comma.