Spectrum

 Been trying to assimilate what all this spectralDecomposition does. The Lesson gives qasm

code to evaluate whenther one' decomposition was done right. (I have added a print()):

                                                                 

Here, running things from pi - for the angle measure. The cos factor is thus negative.

The general case, around the unit circle.

Running the X-gate in the negative

Asked Perplexity for python code that would show the periodicity of unitary matrices,