Posted in 2015
Sixth lecture Quantum Transport
the last one before the semester break. We did Coulomb blockade and I believe we did it good). I’m pretty slow this year, there’s a delay of one lecture, so the the deadline for home work about Coulomb blockade was actually earlier than the lecture(. I feel guilty, yet could not do anything about except the better semester planning six month ago. I have to really hurry up after the semester break.
Evaluation from VvTP
The VvTP, our student society, has a contact group that evaluates the courses given and provides a feedback for the teachers. This is what I got on Wednesday:
Advanced Quantum Mechanics:
Nazarov is very enthusiastic about the content of the course. He is following the book very closely: thatβs a very good thing. The book is very good. Students like this, there is a clear structure in the course. A bit more examples would be nice though, to have some practical view. The problems are very compatible with the book and lectures. Students say that it takes a long time making them, because you really have to understand the content.
The presentations which the students have to prepare are quite good. It would be appreciated if the focus of the course would be a bit more practical in the lectures. Students like the way Nazarov did a survey himself. They appreciated the fact that he is clearly trying to improve his way of teaching. A possible improvement would be to give a quick summary of the content covered at the end of each lecture.β
Actually, it’s pretty encouraging evaluation, thank you). I promise to give the summary every lecture. But, well, my memory is not as good as it used to be X years ago. Perhaps I need to ask assistance from the audience? π
Quantum Transport:
β12 students attending in total. The homework is pretty nice. The course is about applications, but the lectures are not that much into it. Maybe there could be some more exercises to practice and get a better insight.β
A bit surprised that the course is about the applications: but well, it’s rather a compliment π I hated home work, especially extensive one, when I was a student. Good, perhaps next year I can make more of it.
Seventh lecture Advanced Quantum Mechanics
Can’t believe I got so far before the semester break: we have sucsesfully quantized the classical fields! The stuff is still rather technical and boring, yet in the second half we’ve discussed fancy effects of zero-point energy, vacuum fluctuations and uncertainties. It was on time: wish I am so good next time, I expect more difficulties)).
Multi-terminal Josephson junctions as topological materials
if you ask me, is a splendid piece of research. I mentioned the submission earlier: now the preprint is available here.
Abstract:
Topological materials and their unusual transport properties are now at the focus of modern experimental and theoretical research. Their topological properties arise from the bandstructure determined by the atomic composition of a material and as such are difficult to tune and naturally restricted to β€3 dimensions. Here we demonstrate that n-terminal Josephson junctions with conventional superconductors may provide a straightforward realization of tunable topological materials in nβ1 dimensions. For nβ₯4, the Andreev subgap spectrum of the junction can accommodate Weyl singularities in the space of the nβ1 independent superconducting phases, which play the role of bandstructure quasimomenta. The presence of these Weyl singularities enables topological transitions that are manifested experimentally as changes of the quantized transconductance between two voltage-biased leads, the quantization unit being 2e^2/(Οβ).
Renyi entropy in quantum engines
has been published in Physical Review B,
Phys. Rev. B 91, 104303 β Published 18 March 2015.
It has been submitted in August last year, the preprint is available here here.
We evaluate Renyi entropy flows from generic quantum heat engines (QHE) to a weakly-coupled probe environment kept in thermal equilibrium. We show that the flows are determined not only by heat flow but also by a quantum coherent flow that can be separately measured in experiment apart from the heat flow measurement. The same pertains to Shanon entropy flow. This appeals for a revision of the concept of entropy flows in quantum nonequlibrium thermodynamics.
No place for religion at TU Delft?
this is the title of the article in our university newspaper Delta. I did not see it on time, it’s three weeks old.
Pure vanity: I was interviewed for this article.:)
Fifth lecture Quantum Transport
On Friday, we have finished with the quantum circuit theories covering spin transport and transmission distribution. I was reasonably satisfied with the results, there was some interaction with the audience.
I’ve just began the Coulomb blockade: looks like I’ve circumvented half-lecture shift and will have to plan an extra lecture.
Mikhail Titov
has been visiting on Wednesday to give the Quantum Nanoscience seminar among other things. I know him from 2000 when he was a post doc with Carlo Beenakker. Now he is a faculty in Nijmegen.
His work now is mostly in bulk transport, graphene being the most popular and useful application. The talk was about linear magnetoresistance and sign-reversed Coulomb drag in compensated Hall regime. This may sound involved, however, it was quite a fun to follow and understand that all miracles of experiment can be solved if you think clearly, simply but beyond a beaten track.
I even had an urge to do some Coulomb drag: I used to like the phenomenon, yet last time I look at it was 1999.
Infernos
is the name of a European project I’m in. It’s about Maxwell demons. In fact, I always hesitated about the title: on my taste and beliefs, it’s not quite inspiring. However, the project so far went good.
Yet in the end of December I’ve volunteered to prepare a report for the project. In pre-Christmas mood, it seemed a task of a couple of days. Well, I finished it only today :(. I got a psychological clinch with it: could not force myself to start working and going with the work. I knew I do this wrong postponing, and this caused quite some pain – to my feeling, not quite infernal, but I’ve not been there, right? Anyway, it’s good to be through, and it’s good to avoid such clinches for all costs.
Sixth lecture Advanced Quantum Mechanics
was about classical fields. O, I did the half! The topic may feel boring: all oscillators, waves, linear equations can be brought to the same standard form. Perhaps I will have to arrange some entertainment next time. The timing was good: actually, did not expect this π