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Posted in 2011

The Protection of the Mother of God 2011

, this warm authumn feast came to us again. I’m confined in my usual squirrel wheel, no real progress in anything, too busy to think why is it so. Mother, protect me and those around me from consequencies of me being unreasonable.

A rumour has come today of upcoming press report that will be very negative for our Delft University of Technology. While the report is aimed at a small group, it is feared that it will have a serious negative impact on our university as whole. Given the fact that our financial position is reasonably close to disastorous, the consequencies can be devastating. Mother, protect the innocent, do not let the cruel things happen.

Chris Monroe

from Joint Quantum Institute (University of Maryland + National Institute of Standards and Technology) gave today a talk about quantum simulator based on trapped ions. You see we are rich in talks this month, and all are good.

I’ve learned a lot about ion traps, including intimate details like spontaneous exchange of ions in the trap or complete melting of ion micro-lattice in cause of a collision with an alien atom, that happens once in fifteen minutes. All experiments presented were breath-taking in two aspects. First aspect is a challenging complexity of quantum manipulation involved. Second aspect is that the sucsessful accomplishment of the experiment relies on so many fine details: if you go through all conditions required, and imagine that a failure at each step would be fatal, your breath is taken away.

Gerhard Abstreiter

from Walter Schottky Instituut Munchen gave a talk today in our nanoscience seminar. Gerhard Abstreiter is a name and a legend in a field that used to be optics of semiconductors and is called nanoscience now. He is one of few scientists in our big field who can compete with me in beard length.

He started his talk by describing the buildings of Walter Schottky Instituut: one may find it strange if not feeling the affiliation of the speaker with the place and his personal involvement with the materialization of these buildings. He gave a short overview of the research in his group, nuclear-spin engineering of SiGe heterostuctures and hand-made photon crystals being the things that impressed be most.

The main topic was optical spin control in self-assembled InAs quantum dots. Gerhard made introduction with his own pioneering works in optical control of a single dot made in early nineties. Later he elaborated on spin-to-charge conversion by adding a polarized exciton. Last part of his talk was about dynamical nuclear polarization that me and Jeroen Danon were busy several years ago. The results reported have not been obvious, I still have to think about.

Arxiv+ ?

On Thursday, Sergey Frolov has given a talk at Quantum Transport group meeting. Second half of his talk was not scientific. Rather, it was about the imperfections of modern science. I must say I initially disliked this part and even showed my dislike to the speaker. Well, there are many traditions/rules/rites in science that are obviously bad, irrational and harmful for science. Is there a point to criticize those or complain about? One could also complain about the fact that scientists must consume food and get rid of waste thereafter, thus being distracted from the research process. The efficiency of such complains would be rather low. It seems so much more efficient to regard the imperfections as external boundary conditions and silently adjust to them.

Of course, these external boundary conditions become more and stringent and one can already forsee science being totally and irreversibly replaced by priopity programs, topsectoren, european flagships and valorisation efforts. It’s too sad to forsee, this is why Sergey’s talk was so irritating. No hables de la soga en casa del ahorcado.

He even dared to criticise the back-bone of modern natural science communication, the Arxiv, calling this awing oblation effort an anachronistic mailing list and a usenet message board. I was disgusted and decided to talk to him afterwards.

This have changed my attitude. It appeared Sergey didn’t just complain: he has certain ideas and suggestions, and I must admit some of them sound quite appealing. Let me explain the Arxiv+ idea, due to Reinier Heeres an him, in a way I understand it.

A concise definition would be: a tailored collaborative framework build on the top of the Arxiv. Let’s have a large research group, an institution, a formal or informal research network of medium-to-large size. They set up a site that provides Arxiv browsing with a set of additional features: those may include annotations, comments, reminders, google-like likes/dislikes, pools, surveys, highlights… add it yourself.

Sergey has skifully provoked me to list the features I would personally like (at the level of Quantum Transport group or our institute). Here it is:

  • Function for a user to tag the articles with tags like ‘spin-orbit’, ‘theory’, ‘citing QT’,’useful review’. Tag list is better supplied by admin, while the users can request an addition to tag list.
  • Function to add a short comment (signed, dated) to the article like ‘I use Eq. 7 to fit my data, but do not understand its derivation, Vincent, 24-7-2013’ , ‘Cited this in my arXiv:/0789.9087, Sergey, 15-2-2012’.
  • Function to do a convenient tag search like I want to see the list of all tagged with ‘spin-orbit’ and ‘nano-tube’ published in 2010-2013 in ETH.
  • Naturally, tags and comments related to an article should appear whenever you navigate to the article starting from an arxiv+ window: that may be technically challenging since requires interception of http requests, yet the system would be very confusing otherwise.
  • News feature: newly tagged articles, new comments upon arriving to arxiv+.

All this would be useful only if there is a substantial user activity like 5-10 tags/comments per day.

At later stage, one could consider

  1. Function to upload and link to an article raw data/ technical notes/ref.reports/master/PhD theses (local storage should be arranged, requires a permission settings feature), extremely useful on a long time-scale.
  2. Function to make user-specific collections with user-specific comments (if this function is provided from the beginning, no collective effort would ever emerge)
  3. A convenient interface to journal version.

Do you have a feature idea? Please do not hesitate to comment on this or write to Sergey directly.

Quantum to Classical Crossover in Mechanical Systems

This was a workshop held in Lorentz Center this week. In short, nanomechanics. It has been organized by Dirk Bouwmeester, Yaroslav Blanter, Herre van der Zant, and Eva Weig. A peculiarity of the organization were very long talks: 1.5 h with discussion. That’s not always bad, yet in this case a speaker usually attempts to say everything he/she knows.

I was able to attend on Monday, hope the most interesting day of the workshop. Andrew Clealand gave a extensive talk about cooling a resonator with a quibit: in his case, with superconducting qubit. He started with a electromagnetic resonator where very unusual and beautiful states can be formed. Further he described a mechanical resonanor with gigantic piezoelectic transduction. There, the results were less spectatular, though the manupulation of states has been clearly demonstrated. Pierre Meystre gave a detailed overview of the ways to couple and manipulate two resonantors, with emphasis on optomechanical systems. Jörg Kotthaus has presented an account of his research on qualifity factors and transduction of microoscillators. Our Gary Steele talked about nanotubes: and yes, he reviewed almost everything he’s done, yet it was interesting to hear.

I met some people I have not seen for a while, Phil Stamp including.

David DiVincenzo

has recently moved from IBM to newly established Institute for Quantum Information in Aachen/Julich. So it was reasonably convenient to him to drop by Delft and give a talk. Leo DiCarlo has presented the speaker as “a man of selective criteria” hinting on DiVincenzo criteria. David talked about error correction codes in quantum algorithms. His main message was that from a multitude of possible error correction circuits one should concentrate on those who have a geometric meaning and can be thought of being performed on elements of a two-dimensional periodic array. He stated that such schemes are now close to practice and appealed to Leo DiCarlo to move to this direction.

I liked the talk that for me had a series of surreal elements as if I’ve been dreaming (swear I have not). Let me list them.

  • I seemed to understand the subject: all my previous attempts to understand the principles of quantum error correction resulted in much deeper sleep
  • By the end of the talk I had a question. When I started to speak I recognize that I have already posed this question to David in the course of his talk in Delft in 1999.
  • This time David gave a very convincing response
  • David referred to works of Alexey Kitaev and showed his photograph. I immediately recalled that both David and Alexey were active in the field of quasi-crystals (Nobel prize of that particular day, see previous post).
  • So I started to think of implementation of error correcion codes in quasi-crystal lattices. Since I understand no heck in both fields I was trying to combine, that was not an extremely productive thinking. But just in case: let me claim this spectacular idea!

On crystals with five-fold axis

Five-fold symmetry axis is not compatible with translational symmetry and therefore with crystal order, that’s it. To be read in textbooks, and all clever boys and girls do know this. This year Nobel prize in Chemistry celebrates an experimental disproval of this mathematical statement, a remarkable discovery of quasi-crystals, the discovery made accidentally, met first with disbelief and them with euphoria, and almost forgotten now.

Quite some time ago Leonid Levitov showed me a fresh-pressed journal with a diffraction pattern photograph that clearly manifested this five-fold axis. Being a reasonably clever boy, I reacted with expected furiously, citing the textbook. In a couple of weeks, I listened to the talk where Kalugin, Kitaev and Levitov presented the first theory of quasi-crystal order, a break-neck idea of hidden higher-dimensionality of the material. (Actually, I still remember some details of the talk but can’t recall who of the three gave it.) All the authors were PhD students(Correction: was reminded on 9-10-2011 that they were master students)), all were below twenty-five. It looked like golden times of physics came back.

Well, after a while other ideas took over. The authors kept working in the field for a while and contribute a lot.

I find it exteremly unjust that their contributions have not been even mentioned in the scientific blurb that explained the prize. Well, these chemists remain chemists…

On distant supernovae

2011 Nobel prize in physics has been announced. While it did not go to me nor to my friends/colleagues, I think I am reasonably satisfied with the decision. The Nobel committee has acknowledged that we live in Universe, moreover, in an expanding Universe, moreover, the expansion goes faster and faster hinting on lots of dark matter. The cosmologists may be boring and arrogant, and may exploit the natural interest of a taxpayer to things “above” without any measure. Still, they are busy with right stuff.

There’s a really well-written blurb about scientific background
at the Nobel site.

Fluctuations in Mallorca

Second half of the last week I have spent in Palma de Mallorca, participating in the workshop “Nonequilibrium Fluctuation Relations In Quantum Systems”. The workshop has been organized by Rosa Lopez and her colleagues in IFISC, The workshop idea was both interesting and practical: to bring representatives of two communities, (classical) statistical physics and (noisy) quantum transport together to understand the recent developments in the field.

This has worked, we did have an intensive mutual exchange, learn to understand and appreciate each other. We had lovely discussions, especially about entropy production, and did produce lots of entropy in this way. I met Miguel Rubi, Chirstopher Jarzynski, Juan Parrondo.

And learned quite a bit about Palma de Mallorca. In particular, the fact that large cities in California are named in memory of the chapels of a parish curch in a remote Mallorcian village…

Bas Hensen

graduated today. He did it in the group of Ronald Hanson, quantum physics of diamonds, today and I was a member of graduation commission.

In course of the event, Bas Hensen has surpised me a number of times, perhaps more than any other graduating student I recall

  • He is a sucsessful example of “taking graduation in his/her hands”. He came to experimental group, and said he would do “theory”: actually, a design of a new experiment. He never took a screwdriver. Nevertheless, the group was very pleased with his work.
  • His thesis contained, among other things, a fairly complete outline of group theory typed by him personally (not just cut-and-past from a source)
  • The topic concerned producing entanglement by measurement
  • He knew that I always ask the students about rainbow. My impression was that nobody has noticed that.
© 2011 TU Delft