Wednesday, April 25, 2007

Happy Birthday Wolfgang Pauli

Some readers have wondered why we keep announcing birthdays of dead guys. Well. The reason is that I suspect many people scan blogs to find smalltalk topics for the lunch break. You know, causal remarks like: Do you think time is an illusion? or I read today the End of Physics is near! or just a mentioning of (caution, here it comes) The Anthropic Principle can easily lead to eternal lunches.

Therefore, the lunch remark of the day is: did you know that today is Wolfgang Pauli's birthday?

Wolfgang Pauli was born on April 25th, 1900 in Vienna. After receiving his early education in Vienna, he studied at the University of Munich under Arnold Sommerfeld. He obtained his doctor's degree in 1921 and spent a year at the University of Göttingen as assistant to Max Born and a further year with Niels Bohr at Copenhagen. (What I always liked most about quantum mechanics is that I know how to pronounce all the names of the people.)

Pauli is most famous for the exclusion principle which states that identical fermions (like electrons) can not occupy the same state. Thus, fermionic stuff can not clump together arbitrarily, and has an inherent stiffness. Among other things, the Pauli exclusion principle explains why electrons form nice shells around the atom core instead of all sitting in the lowest level, thus explaining the variety of chemical elements.

Wolfgang Pauli received the Nobel Price in 1945 "for the discovery of the Exclusion Principle, also called the Pauli Principle".

There are a lot of entertaining stories around Pauli, which is why he makes a good lunch topic. Among other things, he was known for spoiling experiments by simply being present in the room, an effect that was dubbed the 'Pauli-effect'. Allegedly, Otto Stern even banned Pauli from his laboratory to avoid the Pauli-effect, despite their friendship.

Wolfang Pauli was also known for ruthlessly criticising the work of his colleagues, from which the famous quotation stems

    "This isn't right. This isn't even wrong."

("Das ist nicht nur nicht richtig, es ist nicht einmal falsch!")

Now let me publish this post... just in time for lunch. Have a toast to Pauli!

Monday, April 23, 2007

Nabla

Did you know why nabla is called nabla? Well, I didn't know until today. It is named after an instrument somewhat similar to a harp, called by the Greeks the 'psaltery' and by the Hebrews the 'nabla'. Unlike the harp however, the shape of this early string instrument is very geometric: it is pretty much triangular:




The nabla symbol is used in maths (and physics of course) to denote a differential operator. It was introduced by Hamilton around 1837. Its name apparently goes back to a joke by Maxwell. According to Wikipedia, W. Thomson wrote in 1884:

"I took the liberty of asking Professor Bell whether he had a name for this symbol and he has mentioned to me nabla, a humorous suggestion of Maxwell's. It is the name of an Egyptian harp, which was of that shape"


I am kind of glad he didn't suggest to use the Greek name 'psaltery' as I admittedly have no idea how to pronounce it. You might be interested to hear though that it makes an appearance in the bible, Psalm 33:2

"Rejoice in the LORD, O ye righteous: for praise is comely for the upright.
Praise the LORD with harp: sing unto him with the psaltery and an instrument of ten strings. "


The word 'operator' is a very sophisticated expression for a thing that assigns things to things. The telephone operator for example, assigns incoming calls to the desired connection. Its correct mathematical notation is


[source]



An operator can be almost everything. Your kid who never tidies up is an operator that assigns toys to places in your living room. If you buy tickets for the opera, the online booking system is an operator that assigns seats to the audience.

A differential operators specifically acts on functions by differentiating them. The nabla for example, when applied to a scalar field, gives the gradient of that field. If you think about the scalar field as an altitude in a mountain range, then the gradient points towards the direction where the increase is the steepest.

Operators are the core concept of quantum mechanics. Quantities that in a classical theories are functions, like the position or energy of an object, become operators. To make something useful out of them, they now have to act on a function - that being the purpose of an operator. In quantum mechanics, it is the well-known wave-function that they act on.

But the usefulness of the operator concept is that one can deal with them on their own without applying them all the time. It's a bit like replacing 'classical' money with a credit card. If you want to see something 'real' you have to 'apply' it to an ATM to get cash. Most often the result is quantized, say, you can only get multiples of $10 or so. You also typically have an offset, a smallest possible amount that you can get. But for most cases, you are fine dealing with the card itself. You have to be a bit careful though if you use it together with other cards, say the club card (payback card, member card, VIP card, whatever) from your local groceries. For your total, it matters in which order you present them at the register. We say that the operators don't commute: the result depends on the order of use.

The nabla is essentially the operator that, when acting on the wave-function, gives the momentum. That is, up to a constant - in this case a relevant constant. But this may be subject of another post.



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Saturday, April 21, 2007

Einstein's Bees

Two weeks ago, a friend and I sat in the local Starbucks. I vividly recall we were talking about how small changes in our environment can have a large impact, and the example I came up with were bees who don't only produce honey, but pollinate many fruits. He was stunned to hear about the large effect that a loss of bee population could potentially have on our food supply, and asked me for details. As it turned out, he told this to another friend. Who, one week later, replied (forwarded to me), and asked if he'd seen the recent newspaper articles "You're absolutely correct about the bee problem affecting our food supply!"

Anyway, I only knew that because the recent bee-problem was pointed out to me already last summer, I think by Lubos (I couldn't find the comment though). What is new this April is that the bee-problem got a catchy name: the colony collapse disorder (already on Wikipedia), and is blamed on mobile phones by The Independent: Are mobile phones wiping out our bees?. They argue with the results of a study by German researchers at Landau University:

"Now a limited study at Landau University has found that bees refuse to return to their hives when mobile phones are placed nearby. Dr Jochen Kuhn, who carried it out, said this could provide a "hint" to a possible cause."

The word 'limited' already sounds very suspicious, and indeed the link is more than weak. For one, it is extremely implausible that this effect should have set in rather suddenly last summer. Mobile phone nets have gradually been extended over a far longer period of time. Also, it is very unlikely that such a mobile phone disorientation 'spreads out' as it seems to have done from the USA to Europe, this doesn't make sense at all:

"The alarm was first sounded last autumn, but has now hit half of all American states. The West Coast is thought to have lost 60 per cent of its commercial bee population, with 70 per cent missing on the East Coast.
CCD has since spread to Germany, Switzerland, Spain, Portugal, Italy and Greece. And last week John Chapple, one of London's biggest bee-keepers, announced that 23 of his 40 hives have been abruptly abandoned."


But more importantly, mobile phones are rarely placed in bee hives. If one tries to find out what the researchers from Landau did, it turns out they indeed placed the 'base station of a mobile phone' directly in the bee hive. Now, if you don't speak German, let me be precise here: the German word commonly used for the English 'mobile phone' (or cell phone) is not 'Mobiltelefon', but 'Handy' (also written 'Händi' in best Denglish). The device the researchers used is not a cell phone, but a cordless home phone. What was placed directly in the bee hive was the base station of that phone.

An very conscise description of their experiment is available online. Unfortunately, it is (except for the abstract) in German. But even if you don't speak German, look at the pictures and illustrations

Verhaltensänderung der Honigbiene Apis mellifera unter elektromagnetischer Exposition

There is follow-up article in Spiegel who tried to clarify the misinterpretation of the researcher's results (again in German unfortunately): Werden Bienen tot telefoniert? (Are Bees phoned to death?), which also quotes Prof. Jürgen Tautz, bee-researcher at the university Würzburg: "I am sure: a healthy, not stressed, bee colony will not be affected by cell phone networks."

Ah - I just realized this wasn't even the reason for me writing. No, I meant to comment on the quotation that has been attributed to Albert Einstein in this context:

“If the bee disappeared off the surface of the globe then man would only have four years of life left. No more bees, no more pollination, no more plants, no more animals, no more man.”

(„Wenn die Biene von der Erde verschwindet, dann hat der Mensch nur noch vier Jahre zu leben; keine Bienen mehr, keine Bestäubung mehr, keine Pflanzen mehr, keine Tiere mehr, keine Menschen mehr.“)

If one does a Google search on 'Einstein Bees' it gives 981,000 results today (two days ago it was only 893,000).

I've read a lot of Einstein stuff, and I can't recall I ever came across something remotely like this. Nowhere could I find a source for this alleged quotation. It seems it goes back to this article by Walter Haefeker (see last paragraph), but there it ends without a reference. It is not listed in any book with Einstein quotations. There are various other people who have pointed out that this quotation is most likely made-up, at least completely unconfirmed see e.g. here, here, or here.

Update April 21st: See also Lubos' post.
Update April 29th: Gelf-Magazine has an article about the alleged Einstein quotation titled 'Albert Einstein, Ecologist?' which confirms my doubts about its authenticity

"Roni Grosz, curator of the Albert Einstein Archives of the Hebrew University in Jerusalem, tells Gelf, "There is no proof of Einstein ever having said or written it." While Grosz notes that it is extremely difficult to disprove a quote, he "could not remember even one reference to bees in Einstein's writings."



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Friday, April 20, 2007

Local Warming

Finally, spring arrived in Waterloo. A great weekend to all of you!






        Er isses

        Frühling läßt sein blaues Band
        Wieder flattern durch die Lüfte
        Süße, wohlbekannte Düfte
        Streifen ahnungsvoll das Land
        Veilchen träumen schon,
        Wollen balde kommen
        Horch, von fern ein leiser Harfenton!
        Frühling, ja du bist's!
        Dich hab ich vernommen!


        ~ Eduard Mörike

Thursday, April 19, 2007

Temporary Blackberry Trouble

Sometimes there are funny coincidences... I was just about to write something about blackberries, the fruit, when I heared rumours about technical problems with BlackBerries, the gadgets. Clifford cites reports about yesterday's incident, when the BlackBerries temporary stopped exchanging emails.


Blackberry the gadget is, of course, the first wireless handheld organizer that was able to receive and send email. It's an invention of the Waterloo, Ontario, based company Research in Motion, and earned them a lot of money. So much, indeed, that RIM president and co-chair Mike Lazarides could afford donating $50 million to the University of Waterloo to help establish the Institute for Quantum Computing, and $100 million to establish the Perimeter Institute for Theoretical Physics.

That's the reason why scientist working at the Perimeter get equipped with one of these gadgets once they take over their positions there. And from my somewhat limited experience, these BlackBerries can be quite invasive, as concerns your way of living, since it may happen that you are constantly disturbed by beeps signaling newly incoming emails you have to read immediately ;-).

What brings me back to blackberry, the fruit. Take, for example, this thicket of blackberries:


It is, actually, at the edge of the garden of my parents house. The shrubs provide great fruits in August, and they make a great, impenetrable fence against your neighbours. However, if you do not take care, your lawn is invaded without mercy by this species, and soon, you cannot access anymore the apple trees. It gives you a really cool impression of the hedge around the castle of Dornröschen. So, it's a good idea to peck out the blackberry shrubs entering the garden from time to time, and to make sure to leave no roots behind... That's actually how I spend last weekend, when I visited my mother and she had already prepared a quite a long list of things to do in the garden...


The lesson from this is clear: Blackberries are delicious, and BlackBerries are great. You just should make sure they don't take over your garden :-)



Figure Credits: Wikipedia
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Wednesday, April 18, 2007

SEX

SEX is the official abbreviation of the molecule Sodium Ethyl Xanthate.

To promote spring feelings, 3Dchem has chosen SEX to be the molecule of the month March 2007: you can play around with different positions using their nice java applet.

According to the NICNAS fact-sheet, everything that contains more than 20% SEX is hazardous:


"Under normal conditions (20°C), there is enough moisture in the air to cause SEX to form carbon disulphide, a highly flammable, toxic gas that is readily absorbed through the skin. [...] It is poisonous but there is a lack of information about its health effects.

SEX is readily absorbed by the skin and is a skin and eye irritant [...].

Signs of high exposure are dizziness, tremors, difficulty breathing, blurred vision [...]. It causes severe skin, eye and respiratory irritation."


So, be careful...



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Monday, April 16, 2007

Wireless Power

I have a number of friends who are seriously worried about my sanity. Not because I sometimes have the greatest ideas for anti-gravitating devices or clean nuclear power. Nah, they are used to that. In this case they worry because I spent last week shouting at my laptop. More specifically, I was cursing the whole internet! I was looking for some insights regarding the 'wireless power' that I read about. I actually found a lot of articles. But they are all more or less identical copies, and they all explain nothing - but that with an impressive amount of words.

After a week or so, I gave up. It then occurred to me maybe one or the other reader of our blog understands more about the technical details, so here is what I found out with a lot of open questions.

The issue is how wireless power for home use could work. That is, we are typically talking about distances of some meters or so, over which we want to transmit energy to power technological devices (say, your cellphone), preferably without roasting every human in the room.

To set the base, energy can of course be transmitted without wires. There are generally two ways how this can work:

One is to use electromagnetic radiation. E.g. your microwave does that. Actually, every bulb does that. The problem with this energy transport is if you want to use it over useful distances you either have a sender that broadcasts the energy into all directions, and a receiver that picks up only a part of it. This means a lot of energy is just lost. Or you focus the sender's radiation on the receiver, which means for moving targets you have to track them. (The microwave is a box that avoids radiation loss by reflection, and you don't want to sit in it).

The other possibility is using inductive coupling. In this case, energy is transferred from a sender to the receiver by using the very near field, and the radiation loss is negligible. This technique works pretty good and very efficiently and is in fact used to recharge many devices. The problem is that it only works on really short distances (say, a centimeter or so).

Neither of both ways sounds very useful for wireless power at home. Now, while I was scanning through these articles, I found out that there are currently two ideas on the market that rely on different schemes.

A) The one has been proposed by a group of physicists from MIT, Marin Soljacic (assistant professor of physics), Aristeidis Karalis, and John Joannopoulos (professor of physics). They have a paper on the arxiv about it: physics/0611063. I could also find these slides from a talk one of them (M. Soljacic) gave. There is a news article on BBC, and the story has been echoed with slight alterations, e.g. here, here, or here.

B) The other one is the technology used by a company called Powercast. They have a website that you find here. It it almost void of any information. They have a form that you can fill out and they send you some pdf-files. These again hardly contain any information (except some general explanation about the allowed limits on power density). If you don't want to fill out the form [1], the pdf's are here: 1,2,3,4. They apparently have presented their device on the consumer electronics show 2007, see e.g. here, here, here, or here (they are all more or less identical).

Let me first comment on A: The paper says they propose an 'efficient wireless non-radiative mid-range energy transfer'. Efficient means there is little energy loss. Mid-range means it potentially operates on the distances that we are interested in. Non-radiative means it doesn't use radiation. The idea that they build up upon is a resonance effect. You know that from your car. Your engine causes vibrations, and if you accelerate their frequency changes. If the frequency of the vibration coincides with the resonance frequency of some parts in your car (say the CDs in the glove box) they will also start to vibrate. This does extract energy from the engine, just that for the car this is a totally negligible (though annoying) effect.

Now the technique of A proposes to use a receiver and sender system that are resonant objects. In addition to that they state that they do not use the radiation field for this. Note that a field can very well be time-dependent (oscillating) without actually having an energy flow to far distances. For the sender and receiver they consider two examples: disks and loops. The paper does hardly contain any calculation, it seems there isn't very much one can do analytically with these boundary conditions. But electrodynamics can be treated numerically without too much complications, so that's what they have done. Figure 2 from physics/0611063 shows how that field would look like for the two disks (sorry, I removed the figure due to copyright reasons, see update note below).

Interesting is also Figure 6 which shows how the field gets distorted by a wall (to the right), and by a by sample (the square) that simulates a human (again, sorry, I removed the displayed figure, please check the paper) . In both cases, there is not too much distortion which is really promising. As they write 'the system performance deteriorates [...] only by acceptably small amounts'.

I was wondering why the 'human' isn't placed between the disks, wouldn't you too? But I have to say I find it actually reasonable. As long as you don't hit the resonance frequency you probably don't distort the field too much. A human body is very unlikely to contain resonating parts. Though I wouldn't want to have a pacemaker in such a room. More generally, one should ask how other technological (and metal) objects affect the field. Also, what does the field look like if sender and receiver are not parallel to each other?

But okay, I thought, great. So far I can make sense out of this. But this is the static configuration, in which case there is not really a sender or receiver. It's just two coupled systems. But to describe the realistic situation, one disk (loop) has to be the source that 'powers' the other one. The above figure is perfectly symmetric, so it can't describe this situation.

In particular the question is where is the energy flow localized in that case? I mean, energy is a locally conserved quantity. It has to get from the sender to the receiver somehow. My naive guess would have been, it takes place in that cylindrical part of space whose end-caps are the sender and receiver - this intuition relying on the simple fact that photons like to travel in straight lines. I was looking for something like the Poynting vector of that field, but couldn't find anything. The only 'explanation' I found was from Howstuffworks, which says:

"Electricity, traveling along an electromagnetic wave, can tunnel from one coil to the other as long as they both have the same resonant frequency. The effect is similar to the way one vibrating trumpet can cause another to vibrate."

This, excuse me, is simply bullshit [2]. We're talking about a classical system, energy doesn't just 'tunnel' somewhere. The vibrating trumpet transfers its energy via air molecules. Try it without air, you'll see. (You also find the tunnel-explanation in the BBC News article). In this article at physorg, you will find the statement 'Most of the energy not picked up by a receiver would be reabsorbed by the emitter' which doesn't make sense to me either. Photons don't just turn around and fly back if they were not absorbed.

The reason why this puzzles me is that their paper considers as an example a 'useful extracted power' (p. 15) of 10 W (p.16). Now I would expect this power to be transferred between the two loops, that is, it for a diameter of 30 cm, it is distributed over a surface of roughly 1000 cm2. Distributing the power over a surface that large does of course significantly lower the power density relative to that of a cable. But still one finds a power density of 10 mW/cm2 (The FCC limit e.g. in the frequency range 30-300 MHz is 0.2 mW/cm2). One can of course make the loops larger, just that - if you ask me - already a diameter of 30cm doesn't appear so very handy to me.

In addition to this, I have tried to recall how these resonance effects work. In the symmetric configuration (none of both is a source), there is a phase shift between the oscillations of both coupled systems, and energy is transferred periodically from the one to the other. On the average, this does not lead to an energy flow. In case energy is 'used' on one side, an average flow will take place. However, the energy of the total field is typically significantly larger than the fraction that is transferred. I am not sure I understand all the details, but it seems to me that indeed the extracted energy is only a small fraction of the total field. Then, the power density of the total field is even larger than the above estimate, even though a large part of it does not lead to an effective energy flow, but just goes back and forth [3].

I looked at the slides from the talk, and it seems to me that the configurations examined there indeed have a source and a receiver. But since I didn't hear the talk I am not sure, and again I couldn't find anything about the energy transfer. So I wrote an email to the guy who posted the paper on the arxiv, Aristeidis Karalis. He kindly explained:"Think of two penduli connected with a spring. If you move one, energy will be moved to the other and then back and so on. The energy stays in the system and does not leak out. It just jumps from one to the other back and forth." I am not sure I can make more sense out of 'jump' than out of 'tunnel'.

I repeated my question on where the energy flow takes place, but it seems I exhausted his patience at some point (well, I know, I can be really annoying). Interesting is also what he wrote regarding my question why the human sample wasn't placed between the plates:

"The system of dielectric disks is more affected from extraneous objects than the system of loops. I initially made calculations for the 'human' between the two disks, and the numbers were still viable but worse. Therefore, I chose the positioning presented in the paper, because for application where humans are present most probably the loops would be used, while for applications where disks would be used (e.g. optical regime) the materials have much smaller indices and losses."

But as I said above, I actually believe that a human wouldn't make a big distortion because it's unlikely to hit the resonance frequency.

I then looked who's who on this photo, and I thought maybe it would be more helpful to ask Dr. Marin Soljacic. So I wrote him an email, but he didn't reply - at least not yet[4]. And this is where this story ends.

Then let me summarize what I think about A. If there really is very little energy loss, then it seems to me this energy flow has to take place around the axis between sender and receiver and is roughly distributed over a surface of their diameter. If the efficiency of that is indeed almost independent of the sender's and receiver's relative positions and orientations, this means it is somewhat like an automatically working tracking mechanism. The problem is then that the energy density shouldn't be too high between sender and receiver. (Or you'd want to make sure you don't get in the way.) I am not too good with numbers (famous for loosing factors of 106 or so). So I don't know - given the limits on the power density are fulfilled - how long would it take to charge the average device [5]?

Now to B: In essence the idea is using a broadcaster that operates in 900-MHz range with acceptably small power density. They call that the 'omnidirectional power beacon' and it 'will recharge devices within about a 1-meter range' [source]. This energy can be received by a device they call 'power-harvester'. Since there are constraints on the allowed power density, the field can not be too large which means one can only use it to power really small devices. As they say:

"We have a technology that's here today, with FCC approval, that sends RF signals through the air to power very low- power devices directly or to recharge battery-powered devices," said Powercast vice president Keith Kressin. "Our wireless systems can recharge batteries in any consumer device smaller than a cell phone, from up to a meter away." [source]

It seems they actually have working products, and had a demonstration that impressed many people last month. I have to say though, I don't think I would want to work in an office where LED lights start gleaming through energy they extract from the radiation field around me. No matter if you tell me the limits are compatible with what the government demands.

"You can forget their orientation, forget the use of coils; just watch the LED get brighter the closer you place your device to the Powercaster."

This technology seems to have been developed mainly by Dr. Marlin Mickle and collaborators from Pittsburgh. I checked some of his publications, to find out how efficient this power transfer would be. I found a lot technological details about antennas, but not what I was looking for (I could not access all of the papers). If you do better than I, please let me know.

Besides me feeling uneasy with sitting in that power transmitting field, my problem with B is that I am afraid there might be a considerable loss into radiation. In particular, unlike this article from the Alternative Consumer says, this can hardly be very 'green' . The Alternative Consumer essentially repeats Powercast's information sheet that says nice things like 'Powercast Reduces High-tech Waste' because 'Continuous recharging of batteries via the Powercast Wireless Power Platform has the potential to reduce the huge waste stream of batteries to a mere trickle'. Indeed, instead of rechargeable batteries you then use the power-beacon and -harvester, and instead of transmitting power with negligible loss via a cable you radiate it generously into your apartment where most of it goes byebye to outer space.

In addition, I wonder what happens if the guy in the apartment below me installs a 'power beacon' it his ceiling. And my neighbor to the right. And to the left...

To summarize: I wouldn't buy neither A nor B.

Update, April 17th: Yesterday, I sent an email to one of the authors of physics/0611063, Aristeidis Karalis, asking whether it is okay that I display the figures from paper. He replied that the paper is in the publication process and asked me to remove the figures. I was kind of afraid that would happen. So, I am sorry for the inconvenience, but you'll have to look at the pdf-file.



Footnote 1: You can fill in the address fields with x, it works. They sent only the requested files and no spam.

Footnote 2: The use of the expression 'tunneling' is most likely due to a misunderstanding. The electromagnetic field configuration of the proposed system makes use of the Whispering Gallery modes which have an exponentially decaying tail. From the solution of the wave-equation this is similar to the tunnel-effect in quantum mechanics. Just that in electrodynamics the amplitude is that of the electromagnetic field and not - as in quantum mechanics - a probability amplitude. The typical 'tunnel effect' in which a particle 'jumps' through a classically forbidden region has nothing to do with the above described resonance.

Footnote 3: As Stefan pointed out in this comment, the ratio between the transferred power and that of the total field is of order 1000, which means the total power density would be in the kiloWatt range - far above the allowed FCC limits.

Footnote 4: Yes, I checked the junk folder. I found it indeed possible that PI's highly efficient filter discards MIT-senders as spam.

Footnote 5: As my husband just taught me, with a power of 1.5 W it takes 2 hours to charge a common battery of type AA. That is, the transmitted power they considered is very realistic to applications, and going below it makes the scenario considerably less appealing. To meet the limits on the power density, you either have to wait 100 hours, or increase to diameter of the loops to a meter or so.


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Sunday, April 15, 2007

Leonhard Euler 300

Today is the 300th birthday of Leonhard Euler, the most creative and productive mathematician ever. He grew up in Basel, Switzerland, where he learned the nuts and bolts of the mathematics of his time with the Bernoullis, but left his home town at the age of 20 to never come back, and spent all of his later life in Berlin and Petersburg.


Leonhard Euler (1707 - 1783) in a 1753 portrait by Emanuel Handmann
(Öffentliche Kunstsammlung Basel, via MacTutor)


Euler has left his imprint in all branches of mathematics, and created some new ones, such as graph theory. He also contributed to physics, astronomy, and engineering - Wikipedia has a list of about 50 topics that are named after him. Ed Sandifer, in the February 2007 issue of his monthly column "How Euler did it", presents Euler's Greatest Hits in mathematics. Wow - so many stuff you have probably heard about: the polyhedral formula, the Königsberg bridge problem, the product formula, the Euler-Lagrange equations... Lubos has a nice post on the relevance of many of Euler's discoveries for string theory.

And, of course, there is the famous formula


about which whole books have been written. When I was thinking about something a tiny bit original to post about Euler, I thought I might try to trace the origin of this formula in Euler's writings. Mathworld gives as source of the full Euler identity


page 104 of Introductio in Analysin Infinitorum, Vol. 1. Lausanne, 1748. Now, this can be searched for in the Euler Archive, and we find it as entry E101: the Introduction to the Analysis of the Infinite, volume 1, where "Euler lays the foundations of modern mathematical analysis". The original text is available online from gallica.fr, and here is what we read on page 104:


There it is: From this can be seen how imaginary exponential quantities are reduced to sines and cosines of real arguments. It is


It's written in a now old-fashioned notation - in fact, the notation "i" was introduced only in 1777 by, guess whom, Euler - and in an even more old-fashioned language - but what it says is timeless!




There are several web sites commemorating Euler's birthday, for example at theMathematical Association of America, the Euler Society, and the Leonhard Euler Tercentenary - Basel 2007.
The Euler biographies at Wikipedia and MacTutor have much information and many interesting links. If you want to read a book about Euler's life and time, Leonhard Euler by Emil A. Fellmann has not too much maths and no technical details at all - but it is a very readable biography, has a good choice of illustrations, and conveys a lively picture of a 18th century life in science and mathematics. And there is even a comic about Euler.

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Saturday, April 14, 2007

Black Hole Session

I mentioned some weeks ago that I volunteered for PI's public lecture series 'Black Hole Session'. Originally, I was scheduled for the first Saturday in April, but then somebody from human resources figured out this was Easter, and so I was postponed to this weekend. This turned out to be really fortunate, since I was sick last week and the only noticeable activity I achieved was my nose evolving from a white dwarf to a red giant.

Still, I was really running behind with preparing the talk. The problem was when I realized I actually had time to talk about whatever I wanted, I could not decide on what to talk about. Then I recalled what I found the most exciting when I was a student were not all the things that were known, but the open problems that were left for us to explore. So I thought, instead of talking about all the things we know I would - somewhat unusual for a scientific talk - focus on what we don't know, and where the frontiers of our knowledge currently are. Thus, the title of the talk


    Frontiers of our Knowledge

    Abstract: Theoretical and experimental physics work hand in hand to broaden our understanding about the universe that we live in and man's place in the world. In the 21st century, nature has given us quite some puzzles to solve, in the microscopic (particle physics) as well as in the macroscopic (cosmology) range. These open questions at the threshold of the unknown have lead theoretical physicists to formulate possible solutions whose experimental tests are awaited soon. I will talk about these current limits to our knowledge, and about the insights that new experiments like the Large Hadron Collider can provide us with. A central point will be the possibility of large extra dimensions and black hole production at the LHC.


If you want to classify my current state of mind, I'd say I'm an high energy physicist trying to become a cosmologist. I think that in the soon future more interests will shift from particle physics towards cosmology, which right now I find a tremendously exciting area. So in my talk I wanted to talk about both, cosmology and particle physics, especially also the areas where they overlap e.g. dark matter searches, and what that has to do with the 'big' questions like: Where do we come from? What are we made of? (Why am I spending my Saturday at work?)

Well, at least that was the idea. But I have never before given a talk about cosmology (I don't even know what an 'erg' is. Luckily, nobody asked.) I was really kind of nervous (in addition you should know that this lecture starts at 10am, and I didn't have any coffee because due to some problem with the key cards I couldn't get into my office.)

PI's public outreach program is organized by Damian Pope, who told me the format is rather casual, and the physics knowledge of the audience often pretty mixed. So I thought the best would be not to use too many equations, but to really explain every detail (be honest, usually you don't do that since everybody has seen this figure a million times). Bruno made a very nice introduction, and I looked at the large seminar room getting fuller with people. You're not going to believe it, but soon all seats were taken. In fact, after 15 minutes, Damian asked me to interrupt my talk so we could change into the big lecture hall. As I said to Bruno: I think I'm in the wrong movie.

As you can guess, my timing for the talk was a complete disaster. I had to skip the biggest part of the second half, and I had to promise I would put the slides online, so here they are:

I am afraid the size of the file is rather large because it has a lot of photos. I have thrown out the movies that I showed, you can download them here:

I believe in recycling, so part of what I told today is based on posts I have written here, in particular Dark Matter, The World's Largest Microscope, Anomalous Alignments in the Cosmic Microwave Background (piecewise), Micro Black Holes and Extra Dimensions.

People had a lot of questions. The best question was without doubt: Do you know what caused the big bang? It was a good question, because it didn't ask what caused it, but if I know it. It happens only rarely that I can clearly answer a question with yes or, in this case, with no.

If I find the time, I will write a summary of the talk sometime next week, if you will find it, then you will find it here.

Overall seen, giving the lecture was a great experience. In fact, I volunteered to do it again...

Friday, April 13, 2007

Einstein reloaded

In case the flood of Einstein publications initiated by his 125th birthday in 2004 and the celebration of the annus mirabilis in 2005 hasn't appeased yet your hunger for reading stuff about the "Person of the Century", there is a new biography out now. It's called "Einstein: His Life and Universe", by former TIME managing editor Walter Isaacson. It has been reviewed in the New York Times, and by John Updike in the New Yorker. An excerpt can be found at the TIME magazine web site - I wonder if it is says anything about US media that it is about Einstein & Faith...


Einstein on the beach in Santa Barbara, 1933 (?) (Santa Barbara Historical Society, and Caltech Archives)

It seems that Isaacsons book is strong about Einstein's time in the US, but I am not sure if I want to take the time to read through another 700+ pages Einstein biography. I found Jürgen Neffes recent book a very good reading, with a well-balanced mix of the man and the science, and taking into account now available sources about Einstein's personal life. An English translation is about to appear as "Einstein: A Biography". And for a comprehensive and authoritative exposition of Einstein's scientific work, I still know of no match to Abraham Pais' "Subtle is the Lord".


Einstein with astronomer Charles St. John at the Mt. Wilson Observatory in 1931, examining the apparatus for the (unsuccessful) measurement of the gravitational redshift in the solar spectrum. (The Observatories of the Carnegie Institution of Washington, in: Centennial History of the Carnegie Institution of Washington, p. 142)

Anyway, the TIME magazine excerpt of Walter Isaacsons book is accompanied by a sort of "Einstein FAQ": 20 Things You Need to Know About Einstein, answering questions from "Was Einstein a slow learner as a child?" (he was slow in learning how to speak) and "Did Einstein flunk math?" ("I never failed in mathematics") over "Why did it take so long for Einstein to get a Nobel Prize?" (a longer story) to "Was Einstein disillusioned at the end?" (no, he wasn't).

It is definitely worth a click, if only for the wonderful collection of photos, most of which are not those that one usually sees!



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Thursday, April 12, 2007

Is time an illusion?

Nah, I am not going to answer this question. (Actually, I am not really sure what this question means. You can ask me if I think time is a dimension, then I'd say yes.) I just read this discussion of the question that Wired lists as the second on its list of 'big questions' (another one is 'Why is fundamental physics so messy?'). I just thought it might humor you what people had to say about it. It seems if we'd take a vote on it, the majority believes time is an illusion. Feel free to let me know your opinion.

From the comment section:

Roberto: The unidirectional time in the equations of physics is constructed from the original, circular time.

(now that explains everything)

Guest: does time really exist? Not in the least. Time is a construct. Created by mankind to assert ourselves over the other dimensions. We have freed ourself from the laws of physics and created a new prison, time.

(Gee, I didn't even notice we freed ourselves from the laws of physics. That's what can happen if you live in a small city in west Ontario - someone could have told me!)

Guest: if you ever get the opportunity, use DMT (dimethyltryptamine). you will see far beyond the illusion of time and realize many things that cannot be expained.

(Fat chance)

Guest: Time is an invention of convenience. Kind of like x^^0 = 1 .

(Aside: this is not an invention of convenience but a consequence of smoothness)

Guest: It's a tautological question. Time is what's measured by a clock, just as intelligence is what's measured by an IQ test.

(Comes back to the point that the question, as formulated, is essentially empty.)

Eric: Human sentience requires this illusion to give us the illusion of free will.

Robert: there is no such thing as time, instead it should be thought of as the cycle of mater and energy from light to total entropy to highly energized quantum materials which all together form the macro world

(thats what happens if you 'think horizontally')

Pierre: If we are going to think about time, shouldn't we first ask ourselves "are thoughts real?".

(I link therefore I am).

Jeff M: It doesn't matter - the question is moot.

(Thanks to Jeff M for enriching my vocabulary, I agree. Will try to use 'moot' from now on instead of 'nonsense'.)

pachorazy: if we change our perception of time can we change how fast we age?

(and how do you measure 'fast' if not with 'time'?)

Stuart: I suppose that it does not matter. Time is how we perceive it. What it may theoretically be has no effect on how it IS for us. So... it is what it is.

letibenson: Time is an allusion and here is why-- our congress can tell us when we need to set our clocks forward or back by an hour. If time was real it would be out of there hands

tculp: If we break down the question, we have an initial question - what is illusion?

Time flies like an arrow, fruit flies like a banana. (From the book "Instant Physics")

Alex: Time is a man-made idea, it is a construct of human society used to make life more convenient and easy.

Gary: It might be time to go back to the Greek philosophical definition of the universe and work our way forward again.

(have fun, say hello if you arrive in the 21st century)

Robert: the fascination that many people have these days with wanting to believe that everything happens all at once, there really is no time.

JD Bailey: Time is not an illusion. Time is a multidimensional relationship.

Jim: Life is illusion and time comes from life.

Ric: One of the secrets of TIME, which I have realized, is that TIME itself is the constant we call “infinity”.

Erika: And what about killing time?

Jana: Time is fake. Have a nice day.:)



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Tuesday, April 10, 2007

DreamWorks goes Extra Dimensional

Yesterday I heard on the radio that DreamWorks plans on producing all its films from 2009 on using stereographic 3D. And indeed, a quick check on their website confirms this:

Glendale, CA— March 13, 2007 – DreamWorks Animation SKG, Inc. (NYSE:DWA) announced today its intention to produce all of its films in stereoscopic 3D technology starting in 2009. To best take advantage of the technology, the company will now be creating films utilizing stereoscopic 3D from the beginning of its creative process.
“I believe that this is the greatest opportunity for movies and for the theatrical exhibition business that has come along in 30 years,” said Jeffrey Katzenberg, Chief Executive Officer of DreamWorks Animation.


The first time I saw a movie in 3D was in DisneyWorld Florida, some time in the last century. I vividly recall the movie had an underwater scene with a shock-moment where a large shark came in from the right, and the guy left to me hit me in the face trying to hold off the shark.

The principle with the stereographic 3D is essentially the same as with the red-green glasses. To get a three dimensional image, our eyes need two pictures from slightly different angles, one for each eye. If printed or projected on a screen, these two images can be overlaid, but they have to be separated afterwards.

In the red-green (or sometimes red-blue) version one of the image is displayed in red and the other in green. The filters on the glasses allow only one image to enter each eye. Unfortunately, you cannot really have a color movie when color is used to provide the separation.




A better method is to project the two views onto the screen with a different polarization of the light, and to use glasses that filter out one polarization for each eye.



[Picture Credits]

I have to admit I never really liked these 3D movies, they hardly had any plot and the scenes were never really convincing. It will be interesting to see what DreamWorks Animations makes out of this technology.

And don't miss the trailer for the Bee Movie (In Theaters November 2, 2007).

Sunday, April 08, 2007

Global Warming

Blogging, so I've learned, comes with tags. The best is you make yourself and your blog easily classifiable. You see, people want to know what they have to expect. I would recommend you state in your side bar something like 'I am an atheistic, non-smoking, anti-alcoholic, pro-abortion, anti-war, pro-string, anti-drug, pro-evolution, anti-matter, pro-blematic, unemployed neo-liberalist '. Or the like. Ah, and don't forget to clarify sexual preferences, we don't want to confuse anybody.

The advantage is, visitors don't even have to read what you write to disagree with you.

Anyway. I recently feel like subject to peer pressure, and I am afraid I will have to proclaim an opinion about global warming. I recently stumbled across these lists of

50 things you can do to reduce Global Warming

and I just found out via Lubos that the TIME magazine had a similar list in last week's issue: 51 Things you can do to save the environment.

The present global warming debate is in my eyes very ironic. Initially, I was happy to see how fast the environmental consciousness has increased in the last some years, not only in the USA. See, all these points you find on the list like: cover your pots while cooking, take a shower instead of a bath, reuse your shopping bag, recycle your waste - this is what we were taught in Kindergarten1. When I moved to the USA I was shocked, honestly, to see how little people cared about their environment. Okay, Tuscon AZ might have been an extreme case. But folks, when you go shopping then shut off the engine of your car. And yes, better insulation in housing would significantly reduce AC and heating cost, paper can be recycled, etc, etc. Now what's new about these insights?

To come back to global warming, from a scientific point of view it puzzles me how this debate is lead. The essence has become to scare people with the potential catastrophes that global warming can have. Then tell them it's their fault because of the carbon dioxide increase they cause with every fart. The problem is this entangles several points that were better treated separately.

So, let me first state an obvious fact. The world's natural oil and gas resources are not infinite. Experts may disagree whether we will run out of oil in 30 or 100 years, but that is not the point. If our present high-tech civilizations experience energy shortening, very many things will change very suddenly. This is a huge threat for the organization of the society you live in. Since there are so far insufficient preparations in case this happens, the thing to do is: save energy. These 50 points have a priori actually nothing to do with global warming, but are about energy saving. Whether or not you think global warming is real, you should save energy.

Why? You are convinced that bio fuel is the thing to do, or hydrogen, or nuclear fusion, or you are just an optimist who hopes somebody will come up with something at some point? Gee, there is a line where optimism turns into ignorance. The important thing is called Energy Return on Investment Ratio (EROIR), that is essentially the ratio between energy surplus you get and energy you have to invest Ein. The surplus is the difference between the total energy extracted Eout and the energy that you use, that is

EROEI = ΔE / Ein = (Eout - Ein) / Ein

(In many cases, instead of the EROEI the energy return ratio is used, which is just Eout/Ein).

If we want to access new energy sources, its not sufficient to ask how much can we get out. We have to ask what is the price to pay. I am not an expert on bio fuel and hydrogen powered cars and the like, but none of these technologies is presently sufficiently advanced to replace natural oil and gas, the EROEI is significantly lower.

I am not saying this is not possible. I am saying our civilization is presently not prepared to cope with a significant energy shortage. The reason why this concerns me is that you don't have to be a seer to predict what is going to happen if energy shortage hits us unprepared. Nuclear energy (fission) is a well known, easily accessible technique with a large energy return on investment. Current nuclear reactors return around 40-60 times the invested energy [source].

And then multiply that with the fact that the generation in charge when oil runs out will not be the generation that remembers Czernobyl from first hand.

To come back to the global warming. There is high confidence that average temperature on the earth's surface has been raising by about 0.8 degrees since mid of the 19th century. There are many other indicators of a climate change: differences in temperature between summer and winter, day and night, thickness of the Arctic ice, melting of mountain glaciers, frequency of extreme weather events (floods, storms), shifts in the average days of first frost in winter, first bloom of plants, the end of animal hibernation, onset of bird migrations in spring, decline in maple syrup productivity, and so on and so forth. You can discuss any one of these points if you like (I have my doubts about the maple syrup factor), but the evidence that the climate is changing is overwhelming.

Studies also show that the carbon dioxide level in the atmosphere hasn't been as high as today in the last 650,000 years. The question is of course whether the one is causally connected to the other, and I am not the one to tell you that. But even if you shrug shoulders and say: we don't know, the smart thing to do is not to mess with nature if you don't know what is going to happen.

Why? Darwin has told us the fittest survive. There is a huge number of humans on that planet that fit very good into the present environment. We adapt to changes, but evolution works slowly. If we manage to change our environment faster than we can adapt to it, well, congratulations. The whole human race will get the Darwin award for removing itself from the earth's surface by natural selection. We have the power to cause significant effects on the equilibrium of our environment, and we should be very careful with what we do, or we risk consequences that might be irreversible (we can of course debate whether or not it would be a great loss if the human race vanishes from earth's surface).

Besides this, the most pressing problem today is coping with the present changes, whether you know where they come from or not. One problem that will most likely be worsened by climate change, energy shortage and growing population is illegal immigration. Poorer countries have more problems coping with these challenges; if the situation becomes a threat to survival, people take high risk to get into richer countries - can you blame them? Whether you are in North America or Europe, look at your south borders and imagine what the situation will be like in ten years. Twenty years. Thirty years.

I am afraid covering you pot while cooking is not going to significantly change this. Scaring people with scientifically shaky statements might be effective on the short run, but isn't going to help on the long run. What scares me is how imbalanced this discussion is. I wonder if it is the connectivity and information overflow of our modern world that amplifies our concerns, polarizes opinions, and grossly oversimplifies matters. It is tempting and easy to condense the causes of problems and come up with a 50 point list. Others might argue 10 commandments are sufficient.

My mum always said they missed the most important commandment: You shall not be stupid. In fact I think this is the only one we need. The rest are details.

To summarize:

Save Energy. And support development of alternative energy sources. Whether or not you believe global warming is caused by humans.

Don't mess with nature. As long as you don't know exactly what your actions will cause, don't disturb our environment unnecessarily, and be as little invasive as possible. Whether or not you believe global warming is caused by humans.

Don't deny. Climate changes are a fact and have consequences. We have to deal with these changes. Now. Whether or not you believe global warming is caused by humans.

So, if you want to classify me: I'm a tree hugger. I'm a pro-environment, anti-energy-waste currently sick plastic-bag-reuser who worries about the next generation. I could use a little bit of global warming though. We still have snow up here.


1: I just say "Jute statt Plastik"


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Saturday, April 07, 2007

Happy Easter !





Frankfurt ranks Top 7 City in the Quality of Living

When I moved to Frankfurt am Main nearly 10 years ago, I didn't know that I was going to live in a city with a quality of living ranking among the top-ten cities world-wide! That's what I learned today from the German news magazine Spiegel online, citing from the 2007 Quality of Living Survey by the Mercer Human Resource Consulting company. Here are the results for the ten highest-ranking cities:

RankCityCountryIndex
1ZÜRICHSwitzerland108.1
2GENEVASwitzerland108.0
3VANCOUVERCanada107.7
3VIENNAAustria107.7
5AUCKLANDNew Zealand107.3
5DÜSSELDORFGermany107.3
7FRANKFURTGermany107.1
8MUNICHGermany106.9
9BERNSwitzerland106.5
9SYDNEYAustralia106.5


According to the website describing details about the study, the rankings are based on data collected between September and November 2006, and 215 cities have been considered in the Quality of Living 2007 rankings. For each city, a "quality of living index" is calculated according to criteria which are are said to include Political and Social Environment, Economic Environment, Socio-Cultural Environment, Medical and Health Considerations, Schools and Education, Public Services and Transport, Recreation, Consumer Goods, Housing, and Natural Environment, and which is supposed to summarize the differences in living standards. The index is normalized for New York City, ranking at place 48, to score a value of 100. Its idea is to assess the quality of living for the delocalized workforce of the globalized markets, and supposed to be used to judge whether an expatriate is entitled to a hardship allowance...

I must say I am impressed, and a little bit positively surprised, to see three German cities among the top-ten cities world-wide!

The top cities in the Americas are Vancouver (3rd), Toronto (15th), Ottawa (tied for 18th), Montreal (22nd), Calgary (24th), Honululu (27th), San Francisco (29th), Boston (36th), Washington DC, Chicago (both 44th), Portland OR (46th), New York City (48th), and Seattle (49th).

Of course, there are some caveats connected with this list. For one thing, as stated on the MHR website, one may distinguish between "quality of living", and "quality of life":

A city with a high quality of living index is a safe and stable one, but it may be lacking the dynamic je ne sais quoi that makes people want to live in world-renowned cities such as Paris, Tokyo, London or New York. [..] What makes one person's quality of life better or worse cannot be quantified in an objective index. Therefore, Mercer's quality of living report reflects only the tangible aspects of living in a city on expatriate assignments, and leaves the question of the quality of one's life to those living it!

The second point is that you may wonder about the error bars attached to the index. I didn't see this discussed anywhere on the website, and I wonder how reliable the decimals of the index as stated in the list can be. Moreover, you may naively expect that the the index shows some Gaussian, bell-shaped distribution - I was surprised that this is not the case, and that it is nearly flat:


Now, of course, the top 50 cities are the upper end of the distribution of 215 cities (unfortunately, I could not find the complete data set) but I would have expected a different picture, and a smoother distribution with a clearer decrease with increasing index. And from this distribution, I would estimate the error in the index on the order of at least 1 point.

But even with such an error, it is quite safe to group Frankfurt among the top ten cities or so - and that's nice!



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Friday, April 06, 2007

Virtual Stargazing

Searching for inspiration in the night sky, but it's all cloudy and... snowing again? Or, your husband who knows all the names of of the stars is just getting up and going to work some thousand miles east of you? No problem that the internet can't solve for you: browse the virtual night sky at WIKISKY.ORG.






The site features a map of more than half a billion astronomical objects. You can navigate around it easily by clicking and dragging the map and using a zoom-in/zoom-out sidebar. You can also search on specific objects by name from a database, and it seems pretty tolerant of requests that use informal terms. (Ask for a lobster or a rotten egg and it will find you one.)

[via newscientist.blog]

Thursday, April 05, 2007

Springtime!

ONTARIO, ARPIL 5th 2007: As a tribute to global warming, the major of Waterloo announces the city will change its name to Snowloo.

Tuesday, April 03, 2007

Could Gambling Save Science?

"Could Gambling Save Science" is the title of a proposal by Robin Hanson that was brought into my attention in the comments to Science and Democracy III. The answer to that question is: No. Before I tell you why, let me briefly summarize Hanson's idea.

Robin Hanson's proposal is an interesting scenario which aims to solve problems in scientific research by betting on scientific theories. He starts by summarizing the 'Problems with Academia' and dramatically sets the stage for his suggested cure 'Academia is still largely a medieval guild, with a few powerful elites, many slave-like apprentices, and members who hold a monopoly on the research patronage of princes and the teaching of their sons.' I almost feel sorry for myself.

But he has a point that the current academic system has some weaknesses. I don't want to repeat my take on the problem here (for that see Science and Democracy I, II, and III), so let me just state how I understand him. Hanson claims that the way researchers are awarded and appreciated today favors 'being popular, fashionable, and eloquent, instead of being right'. There is certainly some truth in that, though I don't think the situation is as bad as he makes it seem. Anyway, I was interested enough to learn how he thinks one can improve the situation.

So, he goes on explaining that the process by which 'the academic' receives 'credit' for making claims does not work optimal because academics judge on the quality of their own work, and form a rather closed system in their expertise. He argues that we need a 'specific mechanism' that 'encourages honesty and fair play; the game should be open to anyone to prove him/herself.'


His suggestion for such a mechanism is to bet on the outcome of scientific questions. 'Somewhat like a corn futures market, where one can bet on the future price of corn, here one bets on the future settlement of a present scientific controversy'. This, so he argues, would reward being right over being popular once the question is decided. The betting market would be open for everyone, regardless of education or degree and thus dissolve the boundaries of the rather closed academic system. Since those who eventually were right with their opinion about the scientific question, will win their bet 'Everyone would have a clear incentive to be careful and honest!'. That is, he claims financial profit is the reward that will convert the bad unethical academic to a good and honest guy.

He then investigates several cases and explains how his proposal that he calls 'Idea Futures' would work (see also Wired: Idea Futures).

After this follows a long list of possible objections with answers (which I found really a good idea. I might include something like this in one of my papers as well). Some of the questions came into my mind as well, and I will only pick out these. I don't care very much whether gambling is legal, but one obvious point is that there is no real profit in that game. If the issue to be decided is one of application, there could be real profit but then the 'real thing' to deal with are patents. Hanson's reply to this is 'Being monetarily zero sum does not make betting useless'. No, it doesn't make it useless. But it makes the whole idea far less attractive for anybody interested in making profit - and let us recall that making profit was the motivation he assumes participants have.

He also addresses the point 'Is there enough interest in science questions?' but if he answers it, I don't see how. The rather vague answer is basically 'Idea futures would thrive if it tapped only a small fraction of current interest and effort.' He also points out that it would be important to have the bets properly formulated, and the Idea Futures market therefore needs a certain amount of management and organization to operate smoothly 'Claims should avoid slippery concepts and phrasing which allows many interpretations', a demand that I totally agree on. If such a management would exists, first thing I'd do is require it for all scientific publications... Do we really solve any problem here?

So, here is my opinion: Gambling can not save science. To begin with, science is not lost, and doesn't need to be saved. In fact - excuse me - but I have the impression overall seen it works quite well.

But more importantly, one has to ask exactly which problem Robin Hanson aims at solving. On the long run, there is nature which decides on the value of scientific claims. As I have pointed out in an earlier post, a problem arises in the time between the proposal of a new idea and its verification (or falsification). In the absence of nature as a judge, we have to find other ways to judge on the quality of our work. This is what I call 'the measurement problem'. It is a crucial point because misjudgement in the meantime might mean that the best proposal doesn't survive long enough, or can not be worked out sufficiently, to be verified at all.

This however is not the problem Hanson addresses. Also in his scenario, there is only one ultimate judge that decides who wins the bet, and that is still nature. Though it is not stated explicitly I think he is aware of that: 'Most scientific controversies seem to eventually get resolved enough to settle a bet. [...]. Scientific claims are often defined as claims of "fact" which future evidence could possibly disprove [...]', 'a question about a physical property of a substance, like a bond angle of some new molecule, seems quite resolvable. As a rule, one should prefer questions closer to direct observations'. This means he can not solve 'the measurement problem' on the 'marketplace of ideas'.

Instead, the problem Hanson is concerned with is the time between nature's judgement that promotes one theory to be the best, and the time its inventor receives credits for it. In fact, this is also the problem that he investigates in his examples. I have no doubts that there have been, and still are, sad cases in which the value of a model was only recognized with delay. I do not think however, this is an inherent sickness of academia, but rather the exception than the rule. It is not the main problem that concerns me. As academical research works today, everybody who would learn of a model that explains observations better than the present one, would jump on it and use it. The remaining problem is then one of information distribution, which I believe is, and will further be, significantly improved though the ongoing changes in scientific publishing.

But besides these details, the whole idea fails on a very obvious point: There are undoubtedly scientists who like gambling and betting, as there are in every other profession. But the majority of scientists is not in academia because they want to make profit by investing smartly. If that was their motivation, they had not chosen academia in the first place. I dare to say, the vast majority of scientists would completely ignore the presence of such a betting market (as they did already ignore the proposal altogether). Even if it would possible mean they make profit, they wouldn't be sufficiently interested to pay much attention to it.

Financial profit, which Hanson assumes is the driving motor of everything ('Those who invest wisely would accumulate capital and gain influence, which they could reinvest in discretionary research or in influencing future consensuses.') is just not what drives most scientists. It is probably the case for some, but these are exceptions like those who are eager on 'being popular, fashionable, and eloquent, instead of being right'.

No, the majority of experts wouldn't pay any attention to that betting market. And without experts opinion, the whole system becomes no better than a lottery. Everybody who seriously wanted to make money would chose the stock market. For example, we could ask are neutrinos Dirac or Majorana? That I would think is a question that qualifies for the proposal, and which can be decided examining neutrinoless double-beta decay. But what is going to change for anybody whether or not some physicists or laymen have fun betting on one or the other?

I guess that there would indeed be people - experts and layman - interested in betting on scientific ideas. This is done anyhow, but such a leisure-time activity will not have any backreaction effect on the scientific research itself. It can be quite entertaining though, see e.g. Physicists who fancy a flutter.

The bottomline is: Robin Hanson's proposal is a very interesting toy model, and I give the idea a high creativity and entertainment value. But its a toy model nevertheless. Based on the assumption that maximizing profit it the driving motor for researchers, it is destined to remain an empty farce because it will not attract sufficient experts. These, I am afraid will remain busy drinking coffee with their 'many slave-like apprentices'.



Update: See also Robert Hanson's reply


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Sunday, April 01, 2007

Transatlanticism

Want to visit me but don't know how where Waterloo, Ontario is? No problem, just ask Google maps and get directions. Here is how Google recommends you get from Frankfurt/Germany to Waterloo/Ontario in 59 easy steps, for omitted details, see here.

1. Head west on Berliner Straße/K818 toward Ziegelgasse [0.4 km/1 min]
2. Slight left at K818 [1.2 km/2 mins]
3. Turn right at B44 [2.8 km/6 mins]
4. Continue on A648 (signs for Wiesbaden/F-Höchst/Kassel) [6.2 km/4 mins]
5. Merge onto A66 [16.0 km/9 mins]
6. Take exit 9-Wiesbadener Kreuz onto A3/E35 Köln [153 km/1 hour 18 mins]
...
10. Continue straight onto A3/E40 Entering Belgium [49.5 km/25 mins]
...
14. Continue straight onto A2/E19 Entering France [76.3 km/40 mins]
...
29. Take the ramp onto Quai Frissard [1.0 km/2 mins]
30. At the roundabout, take the 4th exit onto E05 [0.9 km/2 mins]
31. Swim across the Atlantic Ocean [5,572 km/29 days 0 hours]
32. Turn left at Long Wharf [0.2 km]
...
37. Keep right at the fork, follow signs for I-90, Entering New York [244 km/2 hours 26 mins]
...
38. Continue on New York State Thruway W Toll road [10.7 km/6 mins]
50. Merge onto HWY-6 N [24.1 km/23 mins]
...
58. Merge onto University Ave E [3.1 km/4 mins]
59. Turn right at Lester St [0.6 km/1 min]



Very many thanks to Andi for the pointer :-)

Aside: Transatlanticism is a track on the very recommendable album with the same name by Death Cab for Cutie.

Spectator of the show

Next round: String theory is losing the public debate. Have fun, but don't forget that Good physics is conflict, and The End of Physics has been postponed until the return of the Boltzmann brains.


[Pic: Inflatable Boxing Ring by Happyjump]