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Posted in November 2009

Quantum manipulation Josephson LED

I have submitted today an article to Nanotechnology, for their special issue on quantum things. This is collaboration with Leo Kouwenhoven and Fabian Hassler. Fabian Hassler has recently begun a postdoc carreer between Leiden and Delft in the framework of concentration group on quantum information. He is a citizen of Lichtenstein, the only one I know. He is supposed to divide his working time between Delft (to help experimentalists) and Leiden (to do theory?). He enjoyes having an office space in both cities.

Quantum manipulation of Josephson LED was a starting project of Fabian: to play with devices that are reasonably close to those in the fridges of experimental colleagues. He has accoplished this with speed of light: eight weeks have passed since the project formulation! Now we know how to produce entangled photon pairs on demand. We plan to go futher with Josephon LED research starting new year.

 You can see the article on Monday at



Eleventh lecture quantum transport

has been updated in time. I’ve made a majour reshuffle of the material and skipped a topic about Luttinger luquids. The fundamentals of dissipative quantum mechanics needed are explained at more qualitative and appealing level. There are still minor inconsistencies in powerpoints, but this did  not lead to any confusion. I am reasonably satisfied with the work done.

However, to put it frankly, I expected a better lecture. The interaction with the audience was at low level. Though not completely absent: the question about GQ has provoked some reaction. I did feel a certain mistrust, certain unwillingness to follow the lecture. Was it a fault of my presentation or the material still remains difficult to swallow?

If I get no comment, the question will remain for at least a year… 

Ninth Lecture Advanced Quantum Mechanics

was about coherent state and could easily be more coherent.  I still think the overall plan was good. Some words, side stories in the beginning. A simple realistic problem formulation: kicking an oscillator. Easy to solve at classical level. Need to sweat at quantum level. Solve. Analyze. Draw a circle. Then discuss coherence and coherent state in the context of laser. To finish: quick Cooper pair box as coherent states of particles.

I’ve started to slip up from very beginning. The citations and discussion of those suddenly appeared banal if not vulgar. Too much attention to beer: the students did not denomstrate any affection with the subject. I’ve felt the introduction that supposed to be both jovial and philosophical has been lost. Tried to compensate this by giving more attention to formulas and developed a time problem. The second half of the lecture has been hurried up, much to misunderstanding and mistrust. It looked like nobody believed me when I get to Cooper pair box.

There was however a question about coherence and coherent state, even before I was going to approach this topic. So I could recall Francis Bacon and his idol of the forum (gosh, I’ve said: daemon of the market, shoudn’t be that clumsy), a subject that in my mind every natural science student should learn by heart. There were more questions: the interaction with the audience was not a total disaster.





Thanks for 32,000 views

It is my pleasure to report another doubling of number of viewes. The past doubling took place 20 days ago while the blog is running for about 80 days. Thank you very much!

If I had more comments, I could easily beat the feeling that most hits are done by robots rather than humans.  Anyway…


More relics

to be found in Firenze, related to my post of Oct. 23.

Good news for all venerating science: Museum of History of Science reports acquisition of two more fingers and a tooth of Gallileo Galilei. Those have been lost for more than a century and will be on display in March when the Museum reopens. Naturally, after the acquisition the Museum will become Gallileo Museum.

Tenth lecture of quantum transport

was bad bad bad. Me bad. I have not given this lecture for two years: Yaroslav Blanter did it. When I gave it three years ago I sort of liked it. Indeed, the topic is hot (still):qubits. Most elements of the presentation were (and are) fine, the stucture is logical  and particular topics disscussed have been worth discussing. But perhaps I’ve changed too much in these three years: I did not fit the lecture, the lecture did not fit me, and that has been accumulating.

Shamefully,  I did not explain in time what  Rabi oscillation are, although they appeared on transparencies from time to time. Moreover, when a student dared to confront me with this natural question, I a. clearly indicated I did not like the question b.instead of answering, utter a short side-story c. finally, gave clusmy, long and incomprehensive answer. Bet I looked like an ambitious fool. Just appearence: my ambitions are modest.

The main problem was that I really hated the sheets. They did not contain what I needed, instead, they contained a lot of things I did not need. In the course of the preparation I recognized the problem, and went through the set three time to find a reconciliation between me and the lecture. It looked like we reached an agreement. However, the transparencies betrayed me somehow. 

Down with the set, will never use it again. Qubits is a rapidly developing topic anyhow, the lacture must be updated.



Crux II 2

I have skipped the last meeting of our christian society. It appeared that many people have skipped that as well, and the organizers have encouraged us "to keep the flame". So I did my best to attend the meeting on November 19, despite overlapping appointments.

It was interesting. Karel Terwel told us about his parish in Delftshaven: old town being now a part of greater Rotterdam. It dwels in a neat old church ( The parish life is active and flourishing, including missionary and social work in the town. It was nice to learn that the parish is growing and full with young families.

Karel is a busy person: he is a teacher at TU Delft, he is a chairman of the parish council, and, as if it is not enough, he does a PhD study. He hardly has a free evening, and feels bad about: he thinks he should do more for the parish. He got various advices. For instance, it was noted that his TU Delft activities whlist done properly, is also work for God, since He dispatched Karel to Facultly of Civil Engineering. Another advice was not to do PhD studies in the evening: right, evenings are hardly productive as far as intellectually involved work is concerned. A PhD student has compared his lifestyle with that of his Chineese (en thus unbelieving) fellow-students to conclude: they’ve more time to work, it costs time and perhaps quality of PhD thesis to be a Christian.

Well, at least for me the time spend on the meeting was not a waste on expence of my work: I was freshly recharged by seeing my friends in Christ and praying with them. Glory to God.

Eighth lecture advanced quantum mechanics

is one of few lectures in the course where calculational flow is being combined with flow of physics: the number of variuos situations we address is significantly bigger than in most of the lectures. There are also pictures. The material is such that a good presentation seems easy. There was a little time problem before the break and in the end of the lecture, I could use several more minutes. The overal timing was however OK. More serious problem is that I am still missing rhythm of the lecture: some pieces I give too slow and some too fast. There were aslo two many blackboard drawings, many of them were extremporized. They could have been at the sheets.

I think the audience appreciated an effort I made, the attention was not lower than for other lectures. There were quite some questions, they’ve also caught me with the hbar coefficients (no, I do not intentionally put incorrect coefficients in intermediate calculations. To confess, somethimes I intentionally do not correct then: proven to sharpen student’s attention). I’ve made a dramatic statement in the end (though did not have much time for that) to prepare the audience for the coherent state: topic of the next lecture.



Ninth lecture quantum transport

was similar to the second one. I have decided to change something and
one change lead to another one and so on. I have finished changing only
at 23:30. I know what price is to pay: a student has caught me on the third transparency. What belong to the denominator has unfortunately appreared in the numerator. Just two days ago my youngest son got a very bad mark for this. Fortunately, my title protects me from such cruel punisment.

But it was not that bad after all. In fact, I think it was rather good lecture and interesting one – at least for me. I shall improve on the derivation of antilocalization: there must be a simpler and more convincing way to express this. The analysis of experimental curves I guess was comprehensive, at least the students seem to follow. Or is this just my impression?

Had time problem: needed 10 minutes for weak localization. Usually I do not do such things, but my desire not to postpone the topic (it will not fit qubits anyhow) was so great that I asked the students to remain in the class for 10 more minutes. They have agreed. Thank you for this, and I won’ t to it again.

Seventh Lecture Advanced Quantum Mechanics

was more sucsessful than I expected. The students came in big numbers and
good mood, they were attentive and active: perhaps most have had a nice flu-less vacation. The lecture is supposed to be rather technical giving a general introduction to transitions: Fermi Golden rule, relations between emission and absorption, black-body irradiation, all that. Next lecture is supposed to provide examples, be more interesting and contain more material. This is why in the beginning I make a proposal: let’s go a bit faster, so that in the end we can eventually start with the material of eighth lecture. Not only the proposal was accepted: we really managed to do this.

There was a nice discussion around Fermi Golden Rule. It turned out that nobody knew the rule, or at least could not readily recall. Strange: former generations have had at least a vague notion of it. More improvements in bachelor education? Anyway, we manage to have really nice discussion, I guess I could bring the message about the rule, that is in odds with pure quantum mechanics but is needed to make a bridge to real world.

Another interesting discussion concerned the material of the eitht lecture.Thin emission lines, thin absorption lines: They manifest atoms. We know that our Sun consists of atoms: why its emission spectrum is continuous? Well, several years of studying physics does not automatically provide the answer, but we have manage to find one.

I enjoyed both the lecture and the audience.

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