Hello! I have two uncertainties (hehe) about two concepts from a QM time-dependent Schrödinger equation video. The video is I cannot move on further if I don't fully grasp everything he explains in the video. My two issues are: 1) The general solution for the time-dependent Schrödinger equation starts at 55:20.He uses αi for a set of coefficients of states. What exactly are these? the probability densities? probability amplitudes? the absolute probabilities? He mentions any state vector can be written as a superposition of eigenvectors of the energy, so α should be a probability amplitude, so you can calculate it's squared modulus. 2) At 1:03:04 he comes up with the exponential solution e^-iEjt. Where exactly from does he gets α(0) from? Appreciating any kind of answer which would help me shed some light on these two things. Cheers!