23 November, 2009

A city in 140 symbols: Leeds

Leeds has a redbrick university built out of white bricks. But if you look for a good weather in Britain – better go to the south of France.

21 November, 2009

The Hirsch-bar index: leave your boss' name out of the authors list

I think you know what the Hirsch-index is: if you have n papers cited at least n times – then your h-index is n. For instance, if out of your 10 papers two were cited 4 times, and the rest three times, then your h-index is 3. The index was introduced by Jorge Hirsch in 2005, and became an accepted tool to rank scientists within about one year: community found it useful that a scientist's productivity may be described by a single number. However, the h-index does not take into account such important things as the number of co-authors and the self-citations.

Recently Jorge Hirsch himself wrote a preprint, where he proposed a new, ħ (hbar) - index, that is aimed to solve at least one of these problems, multiple co-athorship. Indeed, the "mass graves" (sorry), published by high-energy physicists and the institute policies to include everyone's name to any article, can unreasonably increase the Hirsch-index, with no extra work.

Some of the h-index terminology before describing the ħ-index. You have the h-index n, if n of your papers belong to the "h core". The paper belongs to the h-core if it was cited n times or more. Your co-authors will probably have other h cores, and a given paper may belong there or not.

ħ - index is defined in a similar way: you have the ħ - index m if m of your papers belong to the ħ-core. But, the paper belongs to the ħ-core if it was cited m times or more and it also belongs to the h-core of your co-authors. (Actually, the latter h should be also ħ, but since the index would be extremely difficult to compute in this case, Hirsch decided to relax the condition a bit)

In other words, only if the paper improves the h-index of all the authors, it will contribute to your ħ-index. Imagine that you have the h-index of 20, and you have a paper cited 25 times, co-authored by a student with a h-index of 5. Then, it will be included in your and the student's ħ-index, because it belongs to the h-cores of both of you. But, if you add a third author to this paper, say, a director of your institute with a h-index of 45, the paper will not count for any of you, because it doesn't belong to the director's h-core.

So, if you have 200 papers, cited 44 times each and co-authored by your director, who has the h-index of 45, none of them will count, and your ħ-index will be zero. Hirsch expects this to stimulate young scientists to work independently. However, he mentions, that the ħ-index will be definitely useless for postdocs, since they are used to include senior scientists in their papers.

I wonder whether it will be possible to eliminate self-citations at some point.

20 November, 2009

Theorists vs experimentalists again

Here is how I imagine the difference between experimental and theoretical particle physicists:

Left: Blind Reese can't spot the cheese. Right: Neither Phil can get a meal.

19 November, 2009

The LHC will be launched tomorrow

You may follow it online: here is a live display of the beam status. You may also follow CERN on twitter.

via cherstn (friends-only)

17 November, 2009

Another case of scientific fraud

The ETH Zürich research director Peter Chen decided to step down by the end of September after being accused of data falsifications:

"The institute made the announcement in a press release issued 21 September, saying 'there are suspicions that scientific data may have been falsified in two publications and a doctoral thesis in 1999 and 2000' while Chen was group leader. A panel of five chemists was formed earlier this year to investigate, confirming data had been falsified."

Chen will remain a full professor at ETH.

13 November, 2009

A city in 140 symbols: Frankfurt an der Oder

The Oder river separates Frankfurt from Polish town Słubice. Caravans of German smokers cross the bridge to buy cheap Polish cigarettes.

12 November, 2009

Who cites you is important: a new approach to ranking scientists

We are used to such metrics of a scientist's impact in a field like the number of papers published, how many times they are cited, and the h-index that the scientist has. These parameters are expected to rely on credit given to the researcher by the rest of community. However, they don't account for the important thing, namely who cites the published work.

In a paper recently published in Phys. Rev. E, Filippo Radicchi with colleagues propose a new ranking technique that captures this "who" issue: the citations coming from renowned scientists have more weight than those from less known researchers. The authors focused on physics and used the PROLA journal archive (1983-2006) as a testing ground for the methodology. The results show that the probability to win a major physics prize is more accurately predicted by their new method, than by the other metrics, such as citations count.

The only thing is probably missing here – the "negative" citations. The results may be cited as "doubtful" or "wrong" even by famous scientists, and the trustless paper will be scored higher. However, in the case of a scientist's rank, averaging over all his papers will probably make this contribution negligible.

Here is a website where you may figure out a rank of any scientist, based on his articles in physical review journals published before 2006. This piece of work was also highlighted in Physics.

09 November, 2009

Vitaly Ginzburg Dead at 93

Nobel Laureate Vitaly Ginzburg deceased yesterday due to heart failure. Apart from theoretical physics, he was renowned as an outspoken atheist and irreconcilable antagonist of religious obscurantism. Even being already seriously ill some two years ago, he wrote:

"...I'm 91 years old and suffer from an incurable blood disease, for that reason I cannot walk since about three years ago; I also have another difficulty that I don't feel like describing here. Passing through it would be probably much easier with a belief in God. But, until I'm in full possession of my faculties, I will never address to the mythic God. I would like to emphasise that the illness has no affect on my writings, and I ask my opponents to make no allowances for me..."

30 October, 2009

A city in 140 symbols: Prague

Prague is a charming old city with strikingly large historical center. The hilly landscape favors enjoying magnificent panoramic views.

12 October, 2009

John Fenn and age discrimination

In European academia there is a mandatory retirement age: if a university professor becomes older than 65-68 years (depending on country), he cannot hold a position anymore. This was also the case in the US some 30 years ago, when the Age Discrimination in Employment Act still allowed for the mandatory dismissal of tenured workers.

A few days ago I was told a fascinating story of John Bennett Fenn. He was working at Yale for a quarter of a century, until he reached the mandatory retirement age of 70 in 1987. After a while, the law was changed to fight the age discrimination, and Fenn became officially allowed to get a job. By that time his ex-position at Yale was still vacant, and he applied for it. Believe you or not, he didn't get it.

Eventually Fenn joined Virginia Commonwealth University in 1994, where he started working on the Electrospray ionization technique, for which he shared the Nobel Prize in 2002. John Fenn was 85 by that time and he still remains the oldest Nobel Laureate in Chemistry.

Yale University claimed that Fenn was working on electrospray ionization while still holding a position there. After submitting a lawsuit against Fenn, Yale was awarded over one million dollars and partial patent rights to the technique.

11 October, 2009

A city in 140 symbols: Vienna

Vienna impresses with its calm old-fashioned style. No haste, no rush, just enjoy the legendary chocolate cake and astounding coffee.

10 October, 2009

The moronometer

There is a rumor that a renowned Soviet physicist Arkady Migdal thought up a device dubbed "the moronometer". That was a spool of thread placed in a breast pocket of the jacked in such a way that the thread slightly sticks out. Then Migdal was hanging around and meeting people. During such sporadic conversations a company exclaimed "Hey, you've got a thread there!", and tried to detach it, in fact unreeling the spool. Some folks kept pulling the lengthening thread for a while.

According to Migdal, the company's silliness is proportional to the resulting length of the thread.

Reference (Russian)

04 October, 2009

A city in 140 symbols: Luxembourg

Luxembourg: the admirable capital of the last Grand Duchy in the world. Marvelous architecture is spiced by their own outstanding language.

01 October, 2009

The Journal of Chemical Physics

I'm reading a terrific review by Dudley Herschbach. In the introduction he mentions, that one of the reasons to establish the Journal of Chemical Physics in 1933 was the impossibility to publish any pure theory in the Journal of Physical Chemistry by that time. This remained the case for another two decades or so, unless plenty of acknowledged theoretical results emerged.

Nowadays pure theory is almost never published in science magazines, such as Nature or Science. We definitely need to found another one.

30 September, 2009

The Communist Thesis Competition

A PhD student of the MSU Physics Faculty, young communist V. L. Ginzburg, made a commitment to defend his thesis prior to the university's anniversary.


I don't know exactly, which anniversary is meant there: Ginzburg defended his thesis in 1940, while the MSU was founded in 1755. This might be the 185-years one.

P.S. Don't ask me what the famous theorist is doing in the lab.

29 September, 2009

Sample Cover Letter for Journal Manuscript Resubmissions

A funny thing by Roy F. Baumeister:

"...As you may recall (that is, if you even bother reading the reviews before doing your decision letter), that reviewer listed 16 works that he/she felt we should cite in this paper. These were on a variety of different topics, none of which had any relevance to our work that we could see.

Indeed, one was an essay on the Spanish-American War from a high school literary magazine. The only common thread was that all 16 were by the same author, presumably someone whom Reviewer B greatly admires and feels should be more widely cited.

To handle this, we have modified the Introduction and added, after the review of relevant literature, a subsection entitled "Review of Irrelevant Literature" that discusses these articles and also duly addresses some of the more asinine suggestions in the other reviews..."

28 September, 2009

More Nobel prize predictions

Chaz Orzel organized a "Nobel Prize Betting Pool" - if you want a guest spot in his blog you may submit your guess as well.

Thomson Reuters came up with some quantitative predictions, based on the citation count.

Let's see what is going to happen next Tuesday, when the prize in Physics will be announced.

Color figures for free

It turned out that since the 1st of August the Journal of Chemical Physics publishes color figures in print for free: here is the Editor's announcement.

Not sure I ever read a printed version of any journal...

27 September, 2009

A city in 140 symbols: Budapest

Budapest: a fusion of Europe and the Soviet Union. The castle is gorgeous, but the atmosphere is quite scary: we have seen a hold-up there.

Links for 27.09.2009

1) There is no single future for scientific journals - by Michael Nilsen

2) A speech for the American Academy of Arts and Sciences - by Terry Tao

3) Buying success, Saudi style - Physicsworld.com

4) A bad time to get sick? - NHS reports that a number of hospital deaths rises on the day junior doctors join wards (they call it black Wednesday)

25 September, 2009

Politics and scientific misconduct

It turned out that a paper, published in 2009 by Iranian science minister Kamran Daneshjou has plagiarized a 2002 paper by W. Lee et al. Here is a blog post about it. Later, Nature published a long news article, where other cases of plagiarism are revealed.

This is not a very recent story, somehow: a month ago the Los Angeles Times was doubting the validity of Daneshjou's PhD degree.

This is kind of popular among politicians: a few years ago Russian president Putin was accused in plagiarizing his PhD thesis.

P.S. According to Nature's new investigation there are two Iranian ministers involved.

20 September, 2009

A city in 140 symbols: Berlin

Berlin: a large city with empty streets and not so many tourist attractions. Very multicultural, green and comfortable for living, though.

A city in 140 symbols

My wife an I very much like to travel, so it would be nice to come up with a "travel guide for twitterers". We propose it to be the following: the city should be described in 140 symbols, including the city name, with no more than two sentences. The next post will be about the city we live in, namely Berlin. If you would like to describe any cities within the format, please leave a comment.

18 September, 2009

Papers don't need paper anymore

Here is an interesting essay by Paul Graham about the future of publishing, shared on twitter by Michael Nilsen. The main idea is that "economically, the print media are in the business of marking up paper", in other words they do not sell content, but gain money solely for production. This might be a problem in the era of online publishing.

Today is of no doubt that paper versions of scientific journals will not last for long time. The process has already started: the American Chemical Society has basically interrupted printing anything, except for JACS and two review journals. The New Journal of Physics has no paper version from the very beginning.

An application

Today I've got an application for a PhD position by e-mail. Well, this is probably not the best idea to send those to PhD students...

16 September, 2009

The candle problem

If you are an experimentalist, please just skip it. I'll post something for you tomorrow.

Here is a famous test by Karl Duncker, he created it to study the "functional fixedness". So, you have a candle, a box of thumb-tacks and a book of matches:

The task is to attach the candle to the wall, in such a way that the wax doesn't drip onto the table (or the wall).

This is not kind of complicated, or is it? However the results of Duncker's studies were amazing - people solving the problem just to make fun were much faster than those, who were promised a reward (say, 50 dollars) for being the fastest.

15 September, 2009

Who will be the future Nobel laureates?

The Wall Street Journal listed possible winners for this year and the future. There is also one scientist from Atomic, Molecular and Optical physics community - Daniel Kleppner (MIT).

14 September, 2009

Peer-review reviewed

Most of you have probably seen the recent peer-review survey, and the post in Nature blog about it. Well, some scientists are satisfied by referees of their papers, some are not.

What looks a bit weird to me is the "how to improve peer-review" part. Usually there are two ideas:
i) to make the referee's name open, and
ii) to make the review process double-blind, with both names of authors and reviewers hidden from each other.

Well, if we take "a spherical society in a vacuum", say, an ideal one with no politics involved in research, then the first point might probably work. But I don't understand how can one hide the authors' names: people are used to cite their own work, such as an experimental machine they have built or a code they have written. So, the authors will not be obvious only when submitting their first contribution to the field.

That is surprising that 76% of researchers are favoring the double blind system.

13 September, 2009

How far can you go to get cited?

That's amazing how hard some authors work on promoting their own papers.

Here is a number of submissions to the astro-ph section of the arXive, by time of day, in 10 minute bins:

I took it from the recent investigation by Haque and Ginsparg.

The thing is that 16:00 (US eastern time) is the deadline for the daily submission to the arxive. So, the papers submitted at 16:01 will be the first for the next day and will appear on the top of the daily mailing. You are probably wondering why is that important? Recent research by Dietrich and also the preprint I cited above show that articles appearing the first are more visible and far better cited than others.

No matter how good your work is, just put it on the top of the list.

12 September, 2009

The greatest math problem ever. Part 2.

As a comment to one of my posts, Dave proposed the following puzzle:


what's the next line?

11 September, 2009

Links for 11.09.2009

1) Smoking - the blog of John D. Cook

2) Where do the best mathematicians come from - Daniel Lemire's blog

3) How do geeks propose? Male and female viewpoints.

Some metastable states live pretty long

Usually, speaking about metastable states in atoms we assume that those decay very fast, say, faster than a microsecond. But not in a Helium atom - its metastable state lives for extremely long time.

In the ground state helium has two electrons on the 1s shell, one of which can be excited to the 2s shell, using inelastic electron scattering. In such a way the metastable helium He* is obtained. The thing is that the transition 2s->1s is dipole forbidden, and the lifetime becomes huge: a recent investigation of Hodgman with colleagues shows it to be 7870 seconds, which is longer than 2 hours.

Well, that's a good opportunity to take some sleep during the experiment.

05 September, 2009

Project Eureka

Robert Benea left a comment to "The greatest math problem ever" post, with a link to the Project Eureka website, featuring a huge number of different math and logical puzzles. He also added the problem there, in the "very easy" section.

Two atoms meet in the street...

I've heard a funny anecdote in one of the recent Car Talk shows:

Two atoms meet in the street. One says:
- I feel myself so bad... It looks like I've lost an electron.
- Are you sure?
- Yes, I'm positive!

Sorry guys who already know it.

09 August, 2009

Conference proceedings vs articles in Computer Science

It came as a surprise to me that in Computer Science conference proceedings are more prestigious than peer-reviewed articles (see comments to this post). Furthermore, people never publish papers in journals, considering those to be a waste of time.

This is an opposite of what is going on in physics/chemistry/biology, so I asked Daniel Lemire on twitter whether that is true. Daniel explained to me that before the on-line era, the publication cycle was way too long for such a fast-developing field like Computer Science. Therefore journals traditionally don't have so much authority as conference proceedings, which are much faster for science communication.

06 August, 2009

Angry and calm faces

If you look at this image, the face on the left looks like an angry old man, while the one on the right looks like a calm woman.

Step back from your computer five or ten feet, and you will see that the images seem to change places!

The thing is that coarse features and fine features are distinguished differently at different distances.When both sets of features are blended into one image, the mind sees the different feature sets, depending on the distance of the viewer.

Here is the original post. There is also some real research done on this.

Thanks to Valera Yundin for the link.

05 August, 2009

Bose-Einstein condensation of calcium achieved

Scientists from Physikalisch-Technische Bundesanstalt (German national metrology institute) in Braunsweig recently obtained a Bose-Einstein condensate from about 20 000 calcium atoms. This is the first successful attempt to condense alkaline earth species.

Up to now, Bose-condensation was achieved in atomic gases of a number of alkalis (Li, Na, K, Rb, and Cs), and also of ytterbium, chromium, hydrogen, and metastable helium.

04 August, 2009

Peer-Review 2.0

A new kind of peer-review was featured in a recent post in Nature blog.

Commenting on a blog post about something completely different, a guy nicknamed Liquidcarbon drew attention to an article in Journal of the American Chemical Society, that he found to be completely odd. After less than 24 hours after his "WTF is going on there?", the experiments were reproduced showing results, different from those of the original paper.

Being quite far from pure chemistry, I can not judge whether the conclusions of the article and those of bloggers are correct. But, anyway, here is a good example of how science will probably look like in the future - now we call this Science 2.0.

03 August, 2009

Do you read all the papers you cite?

If the answer is "Yes", it is most likely a lie.

Quite a while ago, Mikhail Simkin and Vwani Roychowdhury from UCLA published a preprint about this, "Read before you cite!". The authors present a statistical approach to estimate how many people who cited a paper, had actually read it. Here "to read" means "to take at least a brief look" or even "to download a copy of the paper".

The main idea of the method is to analyze... the number of misprints in the list of references. For instance, if some paper is cited by a bunch of different articles, with the same misprint in the page numbers, most likely the authors just copy-pasted a reference from each other's work, without even downloading the article. As for me, I faced with this a few times.

The final estimate obtained by Simkin and Roychowdhury is that about 80% of the citers don't read (say, never downloaded) the paper they cite.

Thanks to Daniel Lemire for sharing the link on Twitter!

13 July, 2009

Creating magnetic monopoles in table-top experiments

An interesting article appeared today among PRL Editor's suggestions: Ville Pietilä and Mikko Möttönen "Creation of Dirac Monopoles in Spinor Bose-Einstein Condensates". These guys theoretically describe how one may use a magnetic field to create a magnetic monopole in a Bose-Einstein condensed atomic gas. This paper was also highlighted in Physics, so there is nothing left for me to write about.

The only thing I wonder is what happens if one uses molecular Bose condensate, or a subcritical, but non-condensed quantum gas, and uses the laser field instead of the magnetic one? Or, even worse, uses an electric field to manipulate condensed polar molecules?

Also, a few months ago I came across a paper, where some graphene-based system was proposed to "simulate" a Dirac monopole. But, unfortunately, I cannot remember the link...

12 July, 2009

Links for 12.07.09

1) Ten Creative Re-Invention Of The Light Bulb

2) Scriblink - the online whiteboard. You can draw anything you wish and then send off a link. It is possible to discuss stuff by drawing on the same board in real time. You can also use TeX.

20 June, 2009

Monodromy in a classical system experimentally observed

A few days ago an interesting preprint was published on the arXive: "Experimental demonstration of classical Hamiltonian monodromy in the 1:1:2 resonant elastic pendulum" by Fitch et al. Interesting, the contributors, like for instance Heather Lewandowski, are mainly involved in another kind of business: cold molecules. However, in this piece of work they indeed perform experiments with a classical pendulum, and find some monodromy there (that's probably a bad idea to put a link to something I completely don't understand).

In quantum mechanics monodromy occurs when there are no good quantum numbers. For instance, when a linear molecule is rotating in a free space, the rotational angular momentum J is conserved, and so is its projection to the Z-axis, M. When we turn on an electric field, the space isn't isotropic anymore, and the angular momentum J is not conserved, while its projection to the field direction, M, is. Then, if another field is applied, noncollinear with the first one, no good quantum numbers will remain to describe the molecule. In such a case there are no "good" ways to label molecular states. Also, a strange phenomenon, called "the label switching" appears: labels of states depend on in which order you turn on two noncollinear fields.

When everything goes bad monodromy appears on the scene: this is the case for a molecule in two tilted fields (article with preprint).

Coming back to preprint by Fitch et al, which will appear in PRL soon: this is the first observation of monodromy in a classical system ever. And it's a pleasure to read such a good-written article by guys, usually working in the extreme quantum regime.

19 June, 2009

Efimov states in biology

About forty years ago, Soviet physicist Vitaliy Efimov predicted the existence of some special three-body quantum states. A particular feature of those is that the two-body state (like a diatomic molecule) cannot be formed: the interparticle interaction is still too weak for this. However, a very weakly-bound trimer is possible, due to three-body interaction. Nowadays Vitaliy is a part of nuclear theory group at University of Washington.

Efimov states were experimentally observed by Rudi Grimm's group, only 35 years after the theoretical predictions, here is a paper and a preprint (if you are not a Nature subscriber). You may also wish to take a look at their group page about Efimov states, with links to original Vitaliy's papers (click to "Evidence for Efimov quantum states in an ultracold gas of Cs atoms" highlights from March 15, 2006).

I think there might be some Efimov states in biology, either. For instance, take a sloth bear:

It is also known as a "lip bear", and has long lips indeed:

As for myself, I would never believe that such a creature appeared during a usual Darwinistic evolution. I suppose it to be rather an Efimov state of brown bear, tapir and echidna, with no two-body states possible:




However, this kind of proposal is still to be tested experimentally...

02 May, 2009

WW II in color

Here you can find a lot of colored and black-and-white photos of the second world war, from both sides of the conflict. Extremely interesting.

29 April, 2009

Links for 29.04.09

2) A book by Arnold Neumaier "Classical and Quantum Mechanics via Lie algebras" is available here. It will be published soon by Cambridge University Press.

3) Motion Mountain, The Free Physics Textbook by Christoph Shiller

24 April, 2009

Faraday Discussions

Last week I participated in Faraday Discussion 142: Cold and Ultracold Molecules, presenting a poster there. For those of you who don't know, what Faraday Discussions are I will describe it in two words.

The conference is organized by the Royal Society of Chemistry, it has a centennial history and takes place a few times a year nowadays. This time it was at Durham University, UK. Faraday Discussions are not "real conferences" with long plenary talks and short student's contributions. Actually, they are nothing but... discussions.

People submit their abstracts well ahead of time, about one year before the conference. The best abstracts are selected for oral presentations and the lucky guys are asked to submit full-length papers about their work. Then, after the peer-review process, preprints are sent to all participants, who are expected to read them carefully before coming to the place.

Talks at the discussions are limited by only 5 minutes - it should be just a "reminder" to people, who already read the preprints. This rule is quite strict: there is a special guy sitting next to traffic lights, which are green when you start a presentation. After four minutes the lights are switched to yellow, and they turn out to be red after five minutes. At this point you are interrupted at half a sentence - no other way around.

Presentations are scheduled in such a way that they are more or less about the same subject within a single session. So, a few five-minutes talks are given one after another. Then the discussion begins - the most interesting part, taking about one hour. People ask a lot questions, both technical and general ones, but "comments" are also possible. The latter are short presentations, also restricted by the traffic lights, which are relevant to the main contributions. For instance, a theorist, who came up with some explanation after having read the experimental preprint, can briefly describe his idea and show some slides with results.

All questions, answers and comments (along with the papers themselves) are then collected and published a few months later as a volume of Faraday Discussions, a journal having quite a good impact factor, about 5.0 these days.

I find this kind of format to be much more efficient, than usual conferences, where people may have no questions simply because they haven't got the idea of the work during the talk.

On my webpage you may find my poster as well as two preprints about our project (0903.0811, 0904.0567).

17 April, 2009

arXiv endorsement

Many years ago, the arXive was successfully working without any peer-review. But at some point, they started to get a lot of really odd submissions from science freaks, about new "theories of everything", violation of general relativity theory and other things of this sort.

Therefore, an "endorsement" mechanism was introduced, so anyone who submitted a few papers to archive can recommend a preprint of a new guy to be accepted. This is not a true peer-review, the endorser is only expected to check whether the preprint is about science in general, like it doesn't pretend to prove how stupid Einstein was. Not all the archive sections require endorsement - I guess, only fundamental topics, like high-energy physics do.

I'm an endorser for the atomic physics and chemical physics sections, which is quite useless, since no endorsement is needed there. However, today I've got the first "can you endorse me, please?" kind of message, and, yes, this is one from a science freak. I don't know what to do, I must confess. :-)

03 April, 2009

My scientific webpage

Following the advice of my supervisor, I've finally got a scientific webpage. That's it, essentially. :-)

22 March, 2009

Chemical Physics vs Physical Chemistry

At one of the last conferences I've attended, we've got a nice informal discussion about a usual subject "what is the difference between physical chemistry and chemical physics". We concluded that there might be a following way to distinguish between those. If you measure/calculate the reaction cross section, you are definitely a chemical physicist. But, if you multiply the cross section by the velocity, and therefore measure/calculate the reaction rate, you belong to the physical chemistry community. What is your opinion on that?

13 March, 2009

Is PRL Too Large to Have an ‘‘Impact’’?

Recently there was published a PRL Editorial with such a title. The main message is that only a small fraction of Letters are really highly cited - if one publishes them separately, they will have an impact factor of about 20, while PRL's number is about 7. So, this might be a good idea to reject more papers and accept only revolutionary contributions. However, the problem is that nobody can actually predict how many times a given article will be cited in a few years...

A terrific lectures course

If you work in AMO physics and you are out of reading, here is an excellent course in modern atomic and optical physics by Misha Lukin (Harvard) - the first link here.

27 February, 2009

Yuja Wang plays the Flight of the Bumble-Bee

You have to see that:

A new way for science popularization

Galileo's finger goes on display in Italy - an article by Daily Telegraph:

"The digit will be part of a landmark exhibition marking the 400th anniversary of his first observations of the skies...The finger was removed when the astronomer's body when it was exhumed from his unconsecrated grave and transferred to a mausoleum in a Florentine church in 1737. It is usually on display at Florence's Museum of the History of Science."

Do you really want to become a great scientist?

23 February, 2009

Mathematical Tools for Physics

Yesterday I came across a wonderful lecture notes of math methods in physics for undergrads, namely "Mathematical Tools for Physics" by James Nearing. There is a lot of simple math in there, but with really good explanations where in physics this may be of use. Also James gives a lot of funny math tricks.

I wish I had such a lecture course while studying in university.

18 February, 2009

A new book on QM

A very, very strange book appeared in arxive a few days ago: "Quantum Mechanics" by Hitoshi Kitada (University of Tokyo).

Here are the names of some chapters: "Quantum Mechanical Time Contradicts The Uncertainty Principle", "Definition of local time", "Motion Inside a Local System", "Principle of General Relativity", "Inconsistency of Mathematics?", "Stationary Universe", "Existence of Local Motion", "Local time exists", and so on.

Hm, "stationary universe" in the QM course... Let's take a look at this chapter:

"By nature what is called the universe must be a closed universe, within which is all. We will characterize it by a certain quantum-mechanical condition.We consider a metatheory of a formal set theory S. We name this metatheory M_S, indicating that it is a Meta-theory of S as well as a Meta-Scientific theory as Ronald Swan [46] refers to. The following arguments are all made in M_S....The class φ is the first world, the Universe, which is completely chaotic. In other words, φ is “absolute inconsistent self-identity” in the sense of Kitarou Nishida [41], whose meaning was later clarified by Ronald Swan [46] in the form stated above. In this clarification, φ can be thought “absolute nothingness” in Hegel’s sense."

Oh mein Gott, "in Hegel's sense"... I wonder whether physics students at Tokyo university have to pass an exam on this.

15 February, 2009

Phil Anderson on computations

Here is a quote from a Nobel Lecture of famous condensed-matter theorist Phil Anderson:

"...Very often such, a simplified model throws more light on the real workings of nature than any number of “ab initio” calculations of individual situations, which even where correct often contain so much detail as to conceal rather than reveal reality. It can be a disadvantage rather than an advantage to be able to compute or to measure too accurately, since often what one measures or computes is irrelevant in terms of mechanism. After all, the perfect computation simply reproduces Nature, does not explain her."

While Anderson gave his lecture in 1977, this seems to be even more relevant nowadays.

Another theorist, Phil Bunker, while giving talks, often describes somebody's work as "...these guys with small brains and big computers!"

05 February, 2009

Yeah, well, I'm gonna go make my own ranking, with blackjack and hookers!

... In fact, forget the ranking!

This is perhaps what the Futurama's Bender would say, while working in Moscow State University

In 2008 MSU took the 70th place in the World's university ranking held by Shanghai university. In 2007 and 2006 these were 76 and 70 places. This is actually not bad. For instance, MSU was ranked as 186th university in some other ratings.

What one can do with it? It's kind of simple. The university president decided to make his own ranking, and now MSU has the the 5th place (Russian). The lucky guys that took first four places will be announced this month. 

That's probably a good way to push science and encourage scientists...

03 February, 2009

Doing physics as states superposition

But what the f(t) function looks like? On my opinion, in the vicinity of deadline it may be estimated as

f(t)=Floor(0.5*Cos(t^2) + 1),

with Floor(x) giving the greatest integer less or equal to x

Are they some less rough approximations?

01 February, 2009

Links for 01.02.09

1) A calender with naked French politicians - by Roland Hours.

2) Is massively collaborative mathematics possible? - Gowers's weblog.

3) Thousands of video lectures from the world's top scholars - a terrific project.

4) Lab-initio, a lot of funny science pictures.

5) Italian history of physics archive - some old scientific journals are accessible after free registration.

6) Leningrad Siege: Now and then, from English Russia - shows how Saint Petersbourg waw looking during WWII.

Old books with Google

I never mentioned that apart from partial preview, Google books offers some full-text books to read and download. For, instance, here are books in math, which are out of copyright and can be read for free. Of course, most of them are old, and even ancient as, for instance, "Arithmetical Tables Fitted to the Capacity of Such as are Unskilled in the Art of Numbers" by Henry Walrond, published in 1663. The book describes how to work with numbers, add and subtract them. 

What is interesting for me is the old English, this book is written in. Previously I thought that it will be extremely hard for me to read such old printings. But, surprisingly enough, there is no big difference with the modern language. There are some funny words there, for instance "shew" and "your self", instead of "show" and "yourself".

I wonder why Google finds many more copyright-free books in mathematics, than in physics or in chemistry...

Starcraft Course in Berkeley

UC Berkeley students can now take a course in Starcraft game

"This course will go in-depth in the theory of how war is conducted within the confines of the game Starcraft. There will be lecture on various aspects of the game, from the viewpoint of pure theory to the more computational aspects of how exactly battles are conducted. Calculus and Differential Equations are highly recommended for full understanding of the course. Furthermore, the class will take the theoretical into the practical world by analyzing games and replays to reinforce decision-making skills and advanced Starcraft theory." 

Yes, calculus and differential equations are needed. I guess the same phrase appears in the Introduction chapter of quantum mechanics books.

UPD In one of Taiwanese universities there is a porn course. I wonder whether differential equations are still recommended...

22 January, 2009

Things I don't like in Mathematica. Part II: A writing tool.

Here is what I think about writing in Mathematica. For quite a long time I thought that Mathematica can be used for nothing else but calculations. Later I came across a post of Terry Tao "Write professionally", where (among other good things) he states:

"The standard format for mathematical papers is TeX, AMS-TeX, LaTeX, or AMS-LaTeX; other formats such as Word or Mathematica can cause technical difficulties (and will ultimately need to be converted to a TeX format), and so should be avoided."

The first thing I thought was "No way, I do not believe that somebody uses Mathematica for writing papers." I know a few experimentalists who submit articles in .doc format and are happy with it, due to lack of equations. But, as far as I know, using something but TeX is considered as kind of "mauvais ton" in math community (please tell me if I'm not right).

This post is not really about some disadvantages of Mathematica interface. But such useless options of notebook formatting as e.g. "Journal Article", "Preprint", "Report", "Book" and "Monograph" can inculcate a bad taste of writing papers in students, who may postpone learning TeX. 

Nevertheless, as mentioned by Philip, Mathematica notebooks can be used to write up some daily results with the following data analysis. For a final draft it is better to use something else, though.

19 January, 2009

Things I don't like in Mathematica. Part I: License.

In my daily work I use Mathematica, and I like it very much. About 7-8 years ago, during first years of university, we were mainly using Maple for analytical derivations. Mathematica was considered to be better for numerics, since it was impossible for Maple to do them more or less fast. But nowadays (on my opinion), Mathematica is the best instrument to work with analytical stuff.

However, it is absolutely useless to write about "what I like", so I better describe things which I don't like, and which I hope will be changed soon. First I thought that it will be a little post with a list of disadvantages, but it looks like there is no way to make it short. So, there will be a few posts, and here is the first part - about the license.

In our relatively small and, in general, experimental institute we have about 20 online Mathematica licenses. In other words, twenty people can connect the server and perform calculations in the same time. 

One of my roommates was doing quite extensive computations, often lasting several days. Sometimes his calculations were stopped during the night, because Mathematica suddenly decided to check the online license, and simply interrupted the ongoing evaluation before doing this. 

Why are guys from Wolfram so agitated about the copyright? I guess I know the reason. For instance, in Russia one can buy a DVD with the last versions of Mathematica, Matlab, Mathcad, Origin Pro and other stuff (of total cost more than 10k Euro) for about 5 (yes, five) Euro. And people usually do. Furthermore, the illegal software is widely used for teaching in high schools and universities even nowadays. Hopefully, in Germany this is not the case.

Piracy is a problem. But do you really think that interrupting computations is the best way to attract new users?

The described above was actually the reason for my boss to buy me two home-licenses. But even activating home licenses is usually a pain in the neck, as mentioned in comment of BiophysicsMonkey to Chad's post, and I agree with it. Even updating licenses on both of my computers once a year is some kind of a problem I have to waste my time on, not to mention if you have a lot of machines as Chad does.

I'm completely ignorant in commercial software development, but I do not believe that there is no easier way to preserve the copyright.

18 January, 2009

16 January, 2009

Nature Chemistry

Today I found a little advertising brochure from Nature in my mailbox. It is about a new journal, Nature Chemistry, starting this year (a first issue will appear mid-March). I hope that apart from biochemical articles there will be a bit of usual chemistry in there...

Some photos from Zürich

(Ensuring security)

(Free entrance for everybody? No.)

Took it from here (Russian).

I wonder whether this applies to students, postdocs ad guest scientists as well...

11 January, 2009

Links for 11.01.09

1) The Fine Line Between Plagiarism and Necessary Repetition by Chad Orzel.

2) Next generation search engines could rank sites by “talent” - in the physics arXiv blog.

3) Think atheist - a social network for those who has no shame being an atheist.

4) A Staged Scene in a Gaza Hospital? - a CNN video of a twelve year old boy, dying in the hospital, with remarks of a specialist. The (most likely) fake video, was later withdrew from the CNN website with no further comments.

10 January, 2009

The greatest math problem ever

This is a problem, which can be easily solved by children before entering elementary school. If you want to give it a try, please forget everything you have ever studied. Here it comes:

8809 = 6
7111 = 0
2172 = 0
6666 = 4
1111 = 0
3213 = 0
7662 = 2
9312 = 1
0000 = 4
2222 = 0
3333 = 0
5555 = 0
8193 = 3
8096 = 5
7777 = 0
9999 = 4
7756 = 1
6855 = 3
9881 = 5
5531 = 0

2581 = ?

I took it from here (Russian)

What to do with deleted sections?

When we write an article, we almost always have to omit some material, which has a lot of work behind it. There may be some restrictions to the article length, as in the case of letters to the editor. Also, a referee may ask to shorten appendices and skip insignificant details. An he/she will be right - a short paper is most likely to be read.

So, one usually has a choice: on the one hand an article should describe new and interesting results, without technical stuff interesting for 5% of readers or less. On the other hand, It might be a good idea to keep all the relevant material in the same place. This may be useful for further work of authors, or also for somebody else, who wants to learn from the paper or to work out something similar.

Recently there was a post by "How many deleted sections do you write?", where Daniel Lemire proposes a good idea what to do with deleted pages. Daniel suggests to put them in the article's supplementary material, with a reference in the article. In such a way, one can expect the article to be easily read with an access to all necessary details.

Another way might be to keep all the omitted material in the arXiv preprint, and cite it in the forthcoming paper.

Why one needs peer review?

A few days ago Michael Nielsen published an excellent post "Three myths about scientific peer review". Briefly, in the nonscientific (and sometimes in the scientific) community it is usually supposed that:

i) Peer review system was used since very long time ago. Actually, it was not. For instance, Albert Einstein, while living in Germany, was not used to "independent referees" - in such journals as Zeitschrift für Physik the decision "whether to publish a paper or not" was always made by editors. And, as far as I know, before WWII this journal was considered as much better place to publish than Physical Review. After moving to the US, Einstein had withdrew one of his contributions from the Physical Review, because he "has not authorized the editor to show it to specialists before it is printed". I wrote a little post about this story before.

ii) It is reliable, in other words "it nearly always picks up errors, is a very accurate gauge of quality, and rarely suppresses innovation". Of course, no one can predict the future, and say which piece of work will be a "citation classic" in ten years. Furthermore, there is probably no way to discuss the reliability of peer review since we simply don't know how many revolutionary papers were never published (or were, but in some obscure journals) due to negative referee reports.


iii) It can show what is right and what is wrong in science. This is also not true, because it is impossible to check all math in the manusript, redo computations, not to mention repeating experimental results.

The post of Michael was followed by interesting comments of Daniel Lemire, "The purpose of peer review", induced by another comment of Peter Turney to Michael's post: "I’m sympathetic to much of what you’re saying, but, on the other hand, I know that peer review has immensely improved many of my own papers."

Being nothing but graduate student, I absolutely agree with Daniel and Peter: at least two from three papers, written during the first year of my PhD, were substantially improved after referee's comments. Apart from submitting  the papers, we have always sent preprints to some good friends from our field - always getting positive feedback (some of them may be the referees in the same time, but this we don't know).

In my opinion, the fact of peer review doesn't mean that the article is reliable, correct or "interesting to a wide community of scientists" (as it should be e.g. for Nature and Phys. Rev. Lett.). But, the review process is some kind of necessary (but not the sufficient!) condition for paper to be read and cited in the long-time future. After publication the scientific community will make it clear, whether such a condition was actually sufficient - there will be a lot of readers  and time for it, much more than two referees having three weeks to submit a report.

Of course, no one can read all journals in his field, even if the field is small enough. Let alone that articles show what was done about one year ago, but not now. Almost no one is actually reading journals - conferences and arXive give a perfect taste of what is going on. But if we come across an arXive preprint dated back to 2007 without any journal reference - this looks strange, doesn't it?

And last, but not least, it seems that reviewing good papers is an excellent way to learn how to write good papers.

04 January, 2009

25 amazing people celebrated by Google

I came across a collection of Google pictures designated to scientists' and artists' birthdays. Here is the one for Louis Braille:
I wonder whether anyone has a collection of all Google pictures...