De meningen ge-uit door medewerkers en studenten van de TU Delft en de commentaren die zijn gegeven reflecteren niet perse de mening(en) van de TU Delft. De TU Delft is dan ook niet verantwoordelijk voor de inhoud van hetgeen op de TU Delft weblogs zichtbaar is. Wel vindt de TU Delft het belangrijk - en ook waarde toevoegend - dat medewerkers en studenten op deze, door de TU Delft gefaciliteerde, omgeving hun mening kunnen geven.

Posted in October 2009


Some undergraduate students wonder: why the lectures are so regular even during flu-marked months? The explanation is simple: the teachers are having flu in the semester break. I do have it almost every year: I’ve three kids at home. When I was younger, the flu usually presented a challenge, sometimes you’d defy it and go on, there was something to struggle with: headache, splitting cough, running nose at least. Now it is boring: I just feel like a squased bug, no fun at all. The brain does not seem to be affected: I was guiding phd studens per e-mail and they did not show any unrest.  So I am in full recognitionof the boredom of my existence…

This is not to complain cause I fell it’ll be OVER soon. And this is such a JOY to get back to "normal" state, the state that I normally do not notice nor am satisfied with but which is such a WONDERFUL state. Glory to God.


The merits of a primitive warrior are measured by a number of enemy scalps he/she is able to demonstrate. The merits of a bisnessman are perhaps measured by the total of his/her bank accounts, but this is usually not demonstrated. The quatifier of scientific merits is relatively easy to access, at least with TU Delft subscribtion.  You’d go to ISI web of knowledge,, and ask for somebody’s citation report. They give numbers that show how many times the creative works of prof. X have been cited by his/her colleagues. Nobody would pretend that this quantifies scientific excellence or usefulness or creativity of an individual. Yet the latter three are rather subjective, while the number of citations: here it is. This kind of vanity is more for mature researches, the number stays low while you work hard on your research and grows steadily while you hardly work. There is a certain similarity with a bank account.

So I consulted ISI to check the number for my favourite researcher (shamefully, his name is Yuli Nazarov). And look: I’ve found a nice round number of 6,000. Something rather satisfying: not that it is exceptionally high for my age, not that I find it corresponding to time and energy invested into recearch, yet it shows that the reasearch has been noticed.

The only phrase in the backgound of my mind irritates me, the phrase I have recently heard from a much more merited colleage : "Most theoretical papers are either cited or read". The irritation comes from the fact that I can not decide upon my papers: do I pferer them to be read or to be cited? 

It was so much simpler to demonstrate some dried enemy scalps…

Florence – Firenze

This is of course my wife to decide where to go for a vacation. Yet I could not choose a better destination to investigate the links between science and faith, Firenze citta magnifica, that has been decaying mightly for last four houndred years but has not even reached the steepest moment of decay. Thereby presenting a good example to all Western civilizations.

Take Duomo. This is a multi-functional bulding. One of the main functions is kept from tourist crowds. To access it, you need to cross several barriers: some being in your soul, some in the Duomo. For the latter, you subsequenty talk to three guards. Those are responsive, although not in English. Finally, you get close to the relics, speaking scientifically, remains of human beings preserved for veneration. For us Orhodox the most important object was the head of St. John Chysostomos.  The relics are difficult to see through jewelry of vessels and boxes. No board helps to recognize them. At some stage you  recognize that the whole Duomo
is just a shell, an outer box to keep the boxes with relics. Heavenly perfect and humaly unperfect. Perhaps this is why the Florentians hardly cared about finishing it: its facade has been a painted piece of canvas for three centuries. On a more phylosophical note: are we not just shells to keep our faith in?

And now we want more science. Hit the Museum of History of Science, by far the eldest one: it has been started in 1562. Owing to endless restauro, you can see only a third of the collection ( so the entance fee is very scientifically reduced by a third). Still there is a large amount of old sci instruments from XVI to XIX century, much more than here in Delft. Yet no the original telescope of Galileo promiced. There is another thing missed on display. By tradition of times of relative harmony between science and faith, they keep the middle finger from the right hand of Galileo. Perhaps I should have argued with the guards that I am a professor of physics and ought to venerate the remain. I did not dare and also wanted to spare my wife. She has been alreary slightly confused about motivations of researches by an eldest exposure in the museum. That was a functional celestial globe. As a detail, it is being erected by a satyr, and the globe is not the only thing the satyr has erected.

Let me finish with better example of the harmony passed. In old sacristy of San Lorenzo, the eldest church in the town, one finds a detailed fresco that reproduces stars and planets in the sky with scientific accuracy. From the planet positions one reads the date: its Jule 4, 1442. Yet the significance of the date is not clear yet: more research is needed in this direction…

Seventh lecture quantum transport

was the last in the first half of the semester.  We looked at combination of Josephson junction and Coulomb blockade to understand how one can use it to make quantum devices at home. I like the topic very much and wish the students to share my feelings. I felt indeed a bit more attention from the audience than usual.

Number of things with my presentation went wrong. The introduction into home-made quantum mechanics was too hand-waving, I felt myself loosing the logics of the explanation. Though I listed the main points, they seemed rather unlinked. To circumvent this, we turn to the formulas, and here I went too formal I am afraid. Perhaps for the next time I will have to choose a more uniform style of the presentation. The beginning of the second lecture seemed OK, but I have slowly developed a time problem. As a matter of fact, I developed time problem and could not talk about arrays comprehensively.

Though I am happy I could talk about the vortices and even get some positive feedback from the audience: did not have it years past. Perhaps a student just knew what a vortex is and helped me with this. Thank you.

We agreed that we defy the vacation and meet in three weeks. Perfect.

Thanks for 8000 views

It appears the blog is getting centred around a single dull topic: quickly increasing number of views. I apologize for an inconvenience. Let me explain.

Firstly, the number displays an unusual and interesting dynamics that I can not rationalize or predict. This activates my research instincts and I redard reporting the phenomenon as a part of my scientific duty. Second, let me confess, I like very much to get noticed and appreciated, especiallty if this attention is not deserved or expected (since I’ve abandoned any hope to get appreciated for things deserved).

Thank you very much for this! So I will keep reporting every doubling of the number of views.  

Sixth lecture advanced quantum mechanics

was given in exceptional circumstances of fair weather. I could not recall this occasion for the last lecture before the semester break for all years of my service. Believe me or not, I managed to say more than I was going to. We have started with e.m. field as collection of classical oscillators, a debt from the weeks past. I gave the material in more or less reverse order: first explained the result of the activity, them the activity. Unexpectedly, this appeared to be rather convenient, and I moved reasonably fast. I wonder if the students liked it, yet they did not protest. So accelerated, we have accomplished our main task: field quantization – just before the semester break.

I expected the classical oscillators to be the most boring part of the lecture. Unfortunatelty, I was wrong. The most boring part appeared to be the last one where I talked about zero-point energy, uncertainty relations and vacuum fluctuations. I do not know why. Usually it’s rather interesting, since it goes over "fancy" subject the students have heard about but would like to hear more. Usually the audience is more interested so I also talk in more detail. Perhaps it was unwise to hurry up with this, I could have postponed the discussion till the second half of the semester. However, it’s done, and frankly I am happy to get over with.

There was an interesting discussion afterwards. The idea of a student was that the uniform mass background arising from the zero-point energy should lead to a uniform gravitational potential. So no gravitational field would have been felt. We had to write down an equation to figure out that it can not be true: the gravitational potential from a uniform mass distribution can not be uniform. Yet perhaps such reasoning is a step towards true solution of the problem?

The Protection of the Mother of God

is a feast of Orthodox churches.

On Oct. 1, 911, Constantinople was besieged by a viking-style gang consisting mostly of Russians. The fall of the city seemed inevitable. Most non-military population gathered in churches where the services had been conducted day and night. At four o’clock in the morning st. Andrew, the fool-for-Christ, and his disciple Epiphanus, came to see Our Lady praying in the altar. After the prayer, She has covered people gathered in the church by Her veil, as if protecting them from cold or cloaking from the enemy.

The city was spared by the time. The gang turned away satisfied with a modest tribute. Since that the orthodoxes celebrate the feast of Protection, or Intercession, or Veil: Greek word  ÓêÝðç can mean all of above. It may seem strange that the feast is most loved by Russians, wrong side in the story. It requires some reasoning to gasp that the violence and terror inflicted by Russian gangs (either state-owned or private) abroad must be a minor fraction of that inflicted on their own soil. The conclusion is that Russians need the protecting veil most: to cloak from themselves.

Anyway the protection, the mercy comes to everybody. Mostly undeserved. Glory to God. 

Thanks for 4000 views

it took my blog a month to get first 2000 views and a week to get second 2000. I’ve no rational explanation to this fact, blog stats available to me do not provide one. 

There must be some magics involved, and I was trying to recall the tales my grandma used to develop my social skill. There were three magical spells in the tales, "thanks", "please" and "I promise". If I got it right that time, the first you use if you want something, with the second you politely refuse, and the third you just never-never use cause the powers unleashed can not be controlled by human beings. So it looks like I occasionally made use of the first spell.

So I shall thank you for 4000 views, and I promise …    

Sixth lecture quantum transport

was about Josephson effect in the context of quantum transport. Theoretically, it can be one of the best and useful lectures in the course. It combines information of general use (superconductivity, josephson relations) with something that the students can do with their "own hands", in our case, evaluate step by step, and some fascination about "unusual" processes discussed. This assumes students rady to work with "own hands" and teacher able to fascinate keeping things comprehensible and logical. To my estimation, both resourses were present but not abundant.

Right after the break we get a control question and concentrated on it. The answer has emerged, though slower than I would like it to happen. A "fascinating" introduction to superconductivity meant to provoke a discussion was listened to with attention but did not give rise to a sinlge question. Perhaps the mood was "he speaks riddles,  but may be I understand it later. In case it’s worth understanding". 

And I get to generation gap with both feet. The essence of Josephson dynamics is explained with two words: "pendulum" and "washboard". I’ve heard "washboard potential" from many young people but actually never checked if they think that Washboard is a family name of XIX century mathematician. Can somebody become a good physicist without trying to swing a pendulum with hand? Sometime ago I have tried to explain a non-linear second order differential equation to my phd student by saying "it’s like a pendulum, you know…" This did not work. Naively I thought there are some pendula left in physical practicum. It came out today that this does not seem to be the case anymore.

So let me finish this post with providing proper references for washboard

and pendulum (this is with equations:))      

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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