Fifth lecture advanced quantum mechanics

was a kind of experimental: it combined a story of superfluifity with refreshing the concepts of classical electromagnetic field. Never did it before. The lecture has started with another experiment not set by me. Somebody has experimented hard with the beamer settings. As result, the projection i. caught only a part of my computer screen ii. was a meter below its usual position. I’ve fixed i. but could not deal with ii. after 10 minutes of trying. It looks like my remote control does not give me sufficient priviledges in changing the settings. And I missed by smoking break. So when the lecture has started, steam was hissing from my ears.

To let off the steam (and explain the disorted projection), I gave a rather inconventional introduction to the lecture. I mention that a university education is very broad, there are many things to learn at a university, those may include the lessons of irresponsibility and negligence and getting away with these indespensible qualities. But I hope that my students will get bad marks in these particular subjects etc… It is my hope that the students did not find this introduction too patronising/irrelevant. Anyway I talked from the bottom of my heart, and most understood this.

And I was back to the subject. We got thru superfluidity with no much viscosity. Both in positive and negative sense. All went smoothly: quantum field theory => almost classical field theory => linearization with operators => wreid terms => Bogolyubov hunch=> particles become quasiparticles, and, look, atoms become a sound. "=>" means a simple calculation, we did not do that: this explains zero viscosity. So the students were rather spectactors, did not feel any interaction with the audience.

And got tired upon switching to the classical field. This is not my favourite topic, but with more energy I could make it more entertaining and not just mumbling "from zis ekwatin" and "substitute"… Sorry for zis. Anyway, almost a half of the course is over, we have completed at least one climbing: from "particles" to a top where difference between particles and fiels is hardly seen.

Next week the students will decide if we go through the rest of classical preparatory stuff or just stat quantizing.

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