Recent content by mmgbmm

According to the definition, an operator T that commutes with all components of the angular momentum operator is a scalar, or rank zero, operator. What is the mathematical definition to that statement? How can I prove that the four dimensional Laplacian is a scalar operator? Regards, :biggrin:

What if I selected A = d/dt, what does d(d/dt)/dt means? :confused:

In the context of observables in QM the rate of change of the In the contest of observables in QM the rate of change of the expectation value of an observable A is defined by: d<A>/dt= d< Y | A Y>/dt = < d Y/dt | A Y > + < Y | dA/dt . Y > + < Y | A dY/dt> My question is about the second...