It's mostly just complex linear algebra, finite dimensional. So, think eigenvectors, eigenvalues and operators. Measurements are essentially projection operator

It's mostly just complex linear algebra, finite dimensional. So, think eigenvectors, eigenvalues and operators. Measurements are essentially projection operators. And a little more tricky: the tensor product. The tensor product is the physicists way of saying "and". The Bloch sphere is a clever way of notating a vector. You may need density matrices (aka density operators), that's a bit more involved, but basically it allows you to take a probability distribution over vectors.