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Posted in February 2015

Second Lecture Advanced Quantum Mechanics

on this Monday was reasonably well attended. The topic: identical particles, despite importance and fundamental interest, was rather easy, both for me and for students. This gave enough time to go slow and even made an actual experiment with identical particles 😉 There was a good contact. Hope we can go on in this pace.

First lecture Fairy Tales

was about KdV equation, the spectacular advance of early Dutch science. There were many students. I was flattened with the fact that most were familiar with the Lagrangian, and variational calculations in this context. I begin to believe in progress and knowledge accumulation since I did not quite see this in former generation.

Moreover, the students were able to correctly describe the activities of a theoretical physicist. Well, I was rather inspired with this fact and has spent too much time on introduction for the sake of exact solution technology – just had time to mention it briefly.

First lecture Quantum Transport

has happened today. I was pleased with the number of students: it is significantly higher than year ago. Yet in comparison with the former generation the students looked kind of shy being not eager to respond on my questions and provocations. Perhaps early morning is to blame. Nevertheless, I reacted by going slower. We did not even touch counting statistics: left for the future).

Problem-solving session Advanced Quantum Mechanics

took place on Thursday. Since it was not my show – it is that of Michael Wimmer and Albert Gonzalez – I attended only the first part. I was extremely pleased with the student presentation. Basically, it was about the topic that I have to skip during the lecture and felt guilty about since the topic is nice and rather important for the whole course. The presentation was next to ideal: the topic has been presented clearly, the audience was attending, the message got through.

There were many students at the session. Actually, we have run out of the presentation topics: more students want to present, we need to arrange some extra sessions for this in the second half of the semester.

Christian Glattli

from Saclay has visited us on Wednesday this week. We have had an opportunity to chat about his research on graphene plasmonics and his plans to utilize edge channels in graphene, as well as about my plans with chiral electrons.

His talk was about “levitons”, his recent research on noise in quantum point contact. This drew me very philosophical: I began to think about most general definition of a particle and even ask Christian about)).

First Lecture Advanced Quantum Mechanics

has been made today after a long break – 5 year break. I was delighted to get back to my favorite course, equipped with a text-book “Advanced Quantum Mechanics: A practical guide” by Jeroen Danon and me, the book that came out for the cost of so much time and energy.

The classroom was full: up to the last seat(!), it was pretty inspiring. The audience has reacted well on the questions and jokes: at least a part of it. The topic was a bit dry: we have refreshed ordinary quantum mechanics. To the end of the lecture there was a time problem, the end went too fast. Ok, I warned that the first three lectures are dry.

We’ll see what happens next.

Eduard Driessen

who is presently a postoc in Grenoble with Claude Chapelier has given a talk yesterday. He reported very recent results on low-temperature STM experiments with superconducting nanowires. It is a tremendous technical challenge he has overcame.

The results were many and various. Some were pretty familiar and irritating like the incomplete gap in this disordered superconductor: the thing that has an explanation, yet the explanation so primitive and far-fetched that you feel yourself ashamed that you can’t do it better. Some were generation-binding: the hot spots in superconducting wires have been hot topic in 70s when Eduard’s former supervisors Hans Mooij and Teun Klapwijk were at his stage of the career, and STM experiments of Eduard just neatly visualized the intimate structure of these spots.

Some were teasingly interesting. Eduard pushed a 1nA – tiny – current to the STM and observed a gigantic suppression of the critical current in the nanowire. It is like you add an extra droplet to a river stream – and it does not flow anymore. These droplets must be quasiparticles.
The result suggests that the quasiparticles accumulate being added at a rate of 10^7 per second. This is thus about slow quasiparticle dynamics – a topic of my long interest

Vacuum Cleaning

The floor in my office is covered with a carpet: I guess it’s about 40 years old, it keeps all small dirty sports of the period and displays all shades of bluish grey depending on the sun exposure accumulated for these years. It’s about a year that I noticed the carpet got dusty and dirty. The consultations revealed that this was a consequence of a renewed working agreement with the trade union of university cleaners.

Ok, a detail. Yet about two weeks ago I’ve noticed that I cough more because that much dust. I ask our secretary if I could get a vacuum cleaner somewhere in the building: if you want it good, you do it yourself. No, she said – this is not an option. Yet she promised to investigate the alternatives.

I quickly forgot about and kept coughing. Yet on Tuesday morning the cleaning lady brought the vacuum cleaner and asked politely whether she could perform the action. She did! My carpet has changed the color and it is unusually fresh in my room. Long live the university services!

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