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PROFESSOR: Good moRning. Again, we're left with a little stub of chapter six to finish. This was our first chapter on binary linear block codes. Very briefly, last time we developed the family of RM, Reed-Muller codes, parameterized by R and M. These are codes of length two to the M, and distance 2 to the M minus R for all reasonable combinations of M and R, integers. And the reason I do these first is because it gives us a nice big -- in fact, infinite -- family of codes that kind of cover the waterfront. Let us see what we can reasonably get in terms of the parameters n k d in codes. And, of course, n k t d tell us most of what we know, want to know about the performance of moderate complexity codes in terms of coding gain. And it's easy to see that among these codes, we have sequences in which the coding gain goes -- the nominal coding gain goes to infinity. And we also know that there's at least one sequence, the bi-orthogonal sequence, for which the effec...

PROFESSOR: So again, much of the difficulty here is just making sure you're doing the perturbation theory right and working with the two basis correctly. But now we're in the good position. We can combine our results. So here is what I want to combine. I want, in principle, to combine all the things, all the terms. And we've calculated all the terms to some degree. So we saw the Darwin term only affects l equals 0. On the other hand, spin orbit really requires s dot l. And the state should be acted nontrivially by l. If all your states are singlets, l gives 0 on them. So actually, you have a little bit of an uncomfortable situation because l acting on l equals 0 states will give you 0. But you still have the 1 over r cubed. And the 1 over r cubed has l dependencies here. So it's 0 in the denominator, 0 in the numerator. The whole spin orbit coupling doesn't seem to make sense for l equals 0. So most people say, physically, the spin orbit coupling vanis...

MARKUS KLUTE: Welcome again to 8.701. So this is the fifth section of our introduction. I'd like to talk about the early history and the people involved in nuclear and particle physics. I cover the period from 1820 to the beginning of the Second World War. other elements of the later history of the development of the standard model-- parity violation, CP violation-- those aspects will be covered when we talk about the actual physics involved. But I'd like to give you some more background. Especially since we start the discussion with particle physics, it's good to understand what was the starting ground, which shoulders did people stand on at the time. Important to realize here, at this point, I'm not an historian. I like to read about history. I just finished an interesting book on Einstein. I like to have a good understanding how the people of the time, the time itself, and the physics discovery interacted. It helps me in understanding the process of bei...