Tuesday, November 29, 2011

What is all the thinking good for?

The other day I had to write a text explaining the importance of theoretical high energy physics and quantum gravity for the future of mankind. In layman's terms and less than two paragraphs.

I volunteered to do this because my frontal lobe starts shriveling whenever I have to endure somebody working in this area trying to justify their existence by confidently explaining that spin foams will one day dramatically improve the iPhone or so.

Okay, I'm exaggerating. But as I wrote previously it saddens me considerably that knowledge for the sake of knowledge doesn't seem to count as progress anymore. It's not that I don't value technological progress, I just don't think that's all that can “benefit the future of mankind.” As much as I criticized Slouka's article “Dehumanized”, I agree with him that we should stand our ground rather than adapting to external pressure that asks for material short-term outcomes. I finally wrote the following.

“What are we made of?,” “Where do we come from?,” and “What are the laws of Nature that we conform to?” are fundamental questions about our existence that scientists have studied for thousands of years. The quest to answer these questions and to understand the place of mankind in the vastness of the cosmos has lead to a great many of technological improvements. Material prosperity is a, welcome and desired, result that better knowledge of the fundamental laws of Nature brings. But knowledge by itself has also an immaterial value that feeds our desire to understand the world which brought about planet Earth and conscious life on it.

In the last century we have made dramatic progress with our understanding of space, time and matter, but open problems in today's best theories tell us that our knowledge is incomplete. New observations that can guide our learning have moved to very high energies and large distances. It is subject of our research in the areas of high energy physics, quantum gravity, and cosmology to combine the requirements of mathematical consistency and compatibility with observation to learn about the earliest moments of the universe, the elementary constituents of matter, and the structure of space and time itself. Among the most exciting and unforeseen recent insights is the connection between this research and condensed matter physics that is one of the focus areas at Nordita.

Nordita's website btw has undergone a general overhaul and is now remarkably improved.

You can go and shatter my world view by telling me the actual reason you're working on quantum gravity is that you want to become a billionaire with a new and improved GPS that locates your car keys with a precision of a Planck length.

Sunday, November 27, 2011

New Template

As you can see, we have finally switched to the new blogger template. Feedback is welcome!

Wednesday, November 23, 2011

Book review: "Impossibility" by John D. Barrow

Impossibility: The Limits of Science and the Science of Limits
John D. Barrow
Oxford University Press (1999)

In his book "Impossibility: The Limits of Science and the Science of Limits" John Barrow has carried together everything that sheds light on the tricky question what is possible, practically as well as conceptually. It is an extensive answer to the question of FQXi's 2009 essay contest "What is ultimately possible in physics?" but takes into account more than just physics. Barrow also covers economical, biological and, most importantly, mathematical aspects of the question what we can and can't do, what we can and can't know.

The book discusses paradoxa, timetravel, computabily, complexity and the multiverse, though Barrow never uses the word multiverse. The book was written somewhat more than a decade ago, but the summary of eternal inflation and bubble universes, varying constants and the question if it is still science to speculate about something that's unobservable is timely, and Lee Smolin's cosmological natural selection also makes an appearance. Barrow does mention some of his own work (on varying constants and universes with non-trivial topologies) but only in a paragraph or two.

Barrow briefly introduces most of the concepts he needs, but I suspect if you don't already have a rough idea what cosmology and quantum mechanics is about, some sections will not make a lot of sense. He mentions for example the many worlds interpretation in the passing without ever explaining what it is, and has the possibly shortest explanation of inflation and the expanding universe I've ever seen. But if you've read one or the other book that covers these topics you might (as I) be relieved Barrow keeps it short.

The presentation is very non-judgmental. Barrow essentially goes through all aspects of the issue and reports who has contributed what to the discussion, without imposing an opinion on the reader. He also gives an interesting historical perspective on how our view on these questions has changed esp. with Gödel's contributions. However, the writing reads more like a review than a book in that it lacks a narrative, and Barrow also doesn't offer own conclusions, he just summarizes others' arguments. I don't mind so very much about the lack of narrative since I have grown a little tired by the current pop sci fashion to make up a story around the facts so it sells better, but I'd have expected some original thoughts here or there. It is also unfortunate that the book is very superficial on some topics, for example time travel and free will, and if you know a little about that already you won't hear anything new. On the other hand, if you just want a flavor and some references for further reading, Barrow does a good job. I ceartainly learned about some aspects of the possible and impossible that I hadn't thought about before.

Barrow's book is well structured with a summary at the end of each chapter and a final summary in the last chapter. This is very convenient if you put the book down and only pick it up again a few months later and need a reminder what you've already read.

I've been reading for a while on this book. Since 2008 in fact, if I believe the receipt. The reason it took me so long has very little to do with the actual content of the book which, now that I managed to finish it I like very much, and more mundanely with the representation of that content. The book is printed in tiny and in addition the print is crappy, so I get tired just by opening it and looking at a page. It has a few illustrations that are very helpful and to the point, but not particularly inspired. There are also a few photos. As you can guess however, Hubble Deep Field in a crappy black and white print on some square inch isn't too compelling, and it's difficult to see the Château in Magritte's Château de Pyrénées.

Taken together, you may enjoy this book if you are interested in a summary of aspects of the possible and impossible, but you would be disappointed if you're looking for an in-depth treatment of any particular aspect. The book is well written, though not very inspired, and the scientific explanations are well referenced and, for all I can tell, flawless. I'd give four out of five stars if I had stars to give.

Saturday, November 19, 2011

Google Scholar Citations

Google Scholar has a new feature, Google Scholar Citations, that allows you to generate a profile page with your papers. It also lists citations and calculates the infamous h-index. Have a look at my profile here to see if it's an interesting feature for you.

Is it?

To set up a profile page, you first need a Google account. If you already have one, it takes like 2 minutes or so. If you set up your page and enter your name, you'll be offered a list of papers that might be yours, that you can then edit. Mine was pretty good, probably because my name is not very common. A few papers seem to be missing, some listed items weren't papers but deceased websites that I wrote a looong time ago, and my research statement also appeared, but by and large it worked well.

The citation count is not exactly the same as on inSPIRE. In some cases Google Scholar counts more, in other cases less. It's not clear to me what causes the difference.

And my dear husband is evidently author of a paper with 3990 citations. Yes, I am very proud of him :o)

Friday, November 18, 2011

Spreng's triangle

There, I've done it again. I came across some figure in the passing and ended up digging out the original reference in an attempt to make sense of it. In this case the figure is the energy-time-information triangle, proposed by Daniel Spreng in 1978, also known as Spreng's triangle. It supposedly conveys the message that new information technology (whatever that was in 1978) allows to save either time or energy, or a combination thereof. Clearly, I thought, the paper was written before the dawn of Wikipedia...

Spreng has a background that is noteworthy. Trained as a physicist, he later worked as engineer and developed an interest in economics. His triangle is an attempt to connect these areas, and as such very interesting. The example he starts with is purely thermodynamical. A reversible process, without loss of energy, would take an infinite amount of time. Any faster, and the process becomes irreversible. The faster it is, the more energy is needed (at least in the examples Spreng discusses). So there is a trade-off between time and energy that carries over to manufacturing. Information then comes in as an improved technology that makes the process more efficient, and so, more information saves time or energy. That is the basic idea.

Spreng's original paper is here, but I couldn't get access to it, so I settled for the 1993 remake and the following is my summary. You can find the original version of Spreng's triangle on page 13 of this file. I've redrawn it for your convenience, click to enlarge.

Spreng's Triangle

Spreng's triangle is a plane with 3 axes at 120° to each other. The 3 axes are energy (E), time (T) and information (I) respectively. I have drawn lines with constant time in blue, constant information in red, and constant information in green. In the lower right E=0 corner, that Spreng refers to as the "starving philosopher," one needs no energy, but has an infinite amount of time and all the information in the world. In the lower left, I=0, corner, that Spreng refers to as the "primitive man," one has no information and needs an infinite time to get anything done with maximal energy. In the upper corner, the "industrial man," one has plenty of information and energy to get things done in zero time. The corners are however unrealistic limits that shouldn't be taken too seriously, they're just to show the trends if you move around in the diagram.

Now to define a point in a plane you only need two axes, so the relevant statement here would be that all possible points of combinations E,T,I lie in a plane. I say "would be" because I will argue in the following that though superficially plausible and appealing, I don't think it is actually the case.

In his paper, Spreng discusses in which way energy, time, and information partly substitute for each other from several different aspects.

At some point, he claims for example that in industrial countries on a national level working hours substitute for energy use, citing himself in mentioned earlier paper that I had no access to. So I plotted the working time per year per worker from this table, against the annual energy consumption per capita from this table (in kilogrammes of oil equivalent per year).

I don't know about you, but I can't see any correlation or anti-correlation in that. Well, the data I used is from 2003, so, possibly 40 years ago that looked different, but I can't say I am very convinced. However, this turns out not to be of much importance later, he just uses this because he wants to send a message that civilization should slow down the hamster wheel (invest time) to instead save energy:
"Whether the time saved is simply used to produce and consume more, or whether some saved time is set aside as time for cultural development is of prime importance."

One easily sees from Spreng's discussion, that the "information" he is referring to is ill-defined. To be fair however, it does become clear that he is talking about manufacturing processes and their improvement. So Wikipedia isn't really a counterexample. At some point he specifies information to mean 'relevant' information, yet one doesn't know relevant for what. Maybe it's the information needed to decrease energy or time, but then the argument becomes circular. I think the name "information" is very misleading. What he seems to mean is something like the complexity of a technological process. Not that this is better defined.

However, just when I was about to throw the paper in the garbage, Spreng goes and admits that the "relevant information" is totally ill-defined and pulls the following trick that helped me to make more sense out of his triangle. He says, let's just consider information as an unknown parameter and assume it is measured by the market: "[T]he market measures the information content of goods and services." So, let Y be the market value of a good or service, then he defines information (I) by the following equation
    Y = pL L+ pE E + I

where L is input to production of the good in working hours, pL the price per hour, E is the energy input in some units, and pE the price for that energy unit.

That would indeed define a surface if this equation would be fulfilled, so the question is, does it work? First, we note that this equation almost certainly isn't fulfilled for goods with cultural value like, say, Marilyn Monroe's dress. I don't see what difference it should make for the right side of the equation whether Marilyn or I wear a dress before auction, yet I have some doubts anybody would pay me some million bucks for that, so it does make a difference for the left side of the equation which is no good.

So then let's look at goods without cultural value, if such exist, maybe a banana will do. Still, something seems to be really funny with this equation. The alleged market value of the good doesn't at all depend on supply and demand for that good. I mean, I don't know a lot about economics, but if you're growing bananas in your backyard with input E,I,L and suddenly all bananas in Brazil fall victim to epidemic monkey obesity, your backyard bananas would be in high demand and up goes Y without any change to the right side of the equation.

This is not to say that it is not possible to make sense out of Spreng's triangle, but at least from what's in his 1993 paper it seems to me it would take more work to integrate this idea with economics. Spreng concludes his paper with the words
The importance of new information technology, NIT, in respect of future energy use can hardly be overstated. However, NIT can do two things. It can be used to substitute time by information or to substitute energy by information. NIT can, in other words, both be used to speed up the pace of life (work and leisure), thus promoting a society of harried mass consumers, or it can be used to conserve precious natural resources (energy and non-energy) by doing things more intelligently and improving the quality of life without adding stress to the environment. It is up to the society as a whole, politics of course included, to decide which of the
two roads are taken.”

You could then summarize my criticism as these are not the only two roads. Your NIT can also cost you more energy and more time. Like this damned Windows that never seems to finish updating and keeps popping up a message that I have to restart.

Bottomline: Plausible ideas are the most dangerous ones.

Monday, November 14, 2011

The Oscillating Universe

I came across this short story “The Oscillating Universe” by Dennis E. Piper, published in The Observatory, Vol. 97, p. 10P-10P (1977), (PDF available here), and thought you might enjoy it:

One day the Professor called me in to his Laboratory. “At last I have solved the equation,” he said. “Time is a field. I have made this machine which reverses the field. Look! I press this switch and time will run backwards run will time and switch this press I. Field a is time.” Said he, “Equation the solved have I last at”. Laboratory his to in me called Professor the day one. “For heaven's sake, SWITCH IT BACK,” I shouted. Click! Shouted I, “BACK IT SWITCH, sake heaven's for.” One day the Professor called me in to his Laboratory...

Sunday, November 13, 2011

Nerdy Riddle

What am I?

In the mirror I see three,
ψ is always part of me,
I am always positive
And like the I with double f.

Thursday, November 10, 2011

Open positions at NORDITA

Yes, it's this time of the year again... the time of writing applications. NORDITA has some open positions, and it's a great place, so make sure to have it on your list:

We have about 5 postdoc positions in the areas of astrophysics and astrobiology, atomic physics, biological physics, condensed matter physics, gravitation and cosmology, high-energy physics, nuclear physics, and statistical physics. These are 2 year positions and successful applicants can do their own research, they will not be assigned to a supervisor. The job description is here, and the application form is here. The Deadline is November 15th, so it's time to upload your files now and hit submit.

We are this year also looking for an assistant professor in theoretical condensed matter physics. The job description is here, and the application form is here. The deadline is November 22nd.

If none of that is for you, NORDITA also has a visiting PhD student program. It says in the announcement that this program is primarily intended for PhD students from the Nordic and Baltic countries, but students from other countries will also be considered, so don't get discouraged if you don't know where the Baltic Sea is. Applications will be accepted between November 15 and December 15, the application form is here.

As you know, I am currently on parental leave, but if you have questions about NORDITA, I'll be happy to answer them. Write me at hossi[at]nordita.org

Wednesday, November 09, 2011

New constraints on cosmic strings from the South Pole Telescope

Cosmic strings are stable, one dimensional objects of high energy density that might populate our universe. Cosmic strings can arise in quantum field theories and would form networks that extend throughout the universe. They were discussed three decades ago as a possible origin of cosmological structures, but fell out of favor when that was not compatible with data.

Cosmic strings received renewed interest however since they might appear also in the early universe if superstring theory is taken into account. No longer thought to be necessary to explain present day observational cosmology, the question is now how tightly constrained a possible contribution of cosmic superstrings is and if they may become observable in the soon future, when looked for in the right place with the right means, thus providing a long sought for hint that string theorists are on the right track. For more details, see my earlier post.

A recent paper has now put forward new constraints on the density of such string networks
    Cosmic String constraints from WMAP and SPT
    By Cora Dvorkin, Mark Wyman and Wayne Hu

The brief summary is that the have taken into account new data from the South Pole Telescope and not found anything.

The somewhat longer summary is that cosmic string networks leave an imprint in the anisotropy of the Cosmic Microwave Background (CMB) by actively generating perturbations, even after recombination. Most importantly, they act as lenses for the CMB light, which makes a contribution to the spectrum at large multipole moments or small angular size respectively. See here for an explanation of the CMB anisotropies. The recent measurements from the South Pole Telescope have now much improved the previously available data at large multipole moments. The new data is however perfectly consistent with a string-free universe, which allowed the authors of the above paper to derive improved and tighter constraints on models with cosmic strings.

They are careful to point out however that their constraints directly apply only to the most straigh-forward model of cosmic string networks, and that there are more complicated models (in which cosmic strings are merely meta-stable or there are different types of strings) for which the constraints would look different. In any case, this is yet another negative result for the phenomenology of string theory.

Monday, November 07, 2011

What are natural units?

I noticed that I confused some readers by referring to temperatures in GeV and distances as the inverse of an energy. 15 years ago, when I first learned about natural units, it seemed really fishy to me. Now Stefan has to remind me on occasion that a second is not a distance, and an entropy is not dimensionless. Since I've experimented lately with some new software, I put together a few slides on the use of natural units and youtubed them.

At 3:20min it should be 5000K, not 500K, sorry about that. At 3:30min, Lara tried to eat the keyboard.

Wednesday, November 02, 2011

Grassroot funding for science: A good idea?

Yes, I do give money to homeless people in the street. And, yes, I do on occasion donate to charity. Yet I am divided about the benefits of recent crowdfunding services that promise to help researchers to directly raise public money. Some of these services that collect money are dedicated to specific research areas, others are broadly defined, and most are US-based. Here is a selection:

The Eureka Fund is a U.S. 501(c)3 non-profit organization that collects money for energy and environment research. Proposals are reviewed by a scientific advisory board. If you look at the list of projects and the donations received, the success is not exactly stellar, even though Eureka Fund was featured in the NYT in April this year.

Fund Science is another US based micro-funding organization. According to the brochure, they have applied for 501(c)3 status. They are dedicated to help funding young researchers and pilot projects who have difficulties obtaining funding in other ways. In the first round however, they invite proposals only for "doctoral students pursuing hypotheses related to the pathogenesis or modeling of diseases including Crohns and Familial Mediterranean Fever."

A broadly imagined attempt is Sciflies.org, but the website is mostly filled by placeholders instead of content and nothing seems to be happening there. This is funny since Joanna Scott from Nature Network reported last year that the initiative was on its way. Maybe something went wrong there. The Facebook site and Twitter feed are equally deserted.

Then there is the SciFund Callenge, funded by two biologists in California. This fundraising agency runs through RocketHub, a crowdfunding organization based in New York. Maybe because they didn't attempt to reinvent the wheel of crowdfunding, their project list looks decent.

One last example: OpenGenius, which has been celebrated in the press, has an optimistic vision in which scientists and funding agencies propose projects for public funding and the projects are peer reviewed by a "global and highly motivated community." This project is noteworthy because it seems to be not US-based. The website suffers from a certain lack of actual information, but amounts of money are named in EUR and the partners are all Italian.

Needless to say, I think it is a terrific idea to make use of a simple interface that enables researchers to raise some additional money, may that be to replace the ancient lab fridge or to organize a conference. Much like giving some Euros to the homeless guy in the street, money serves to make life a little easier and the day a little brighter.

But beyond little extras, funding research by appealing to the public is not a good trend. It doesn't solve any systemic problem, much like dropping some Euros into a hat doesn't get homeless people off the street. The primary problem with scientific funding today is a lack of risk-taking and commitment: The ideal research project doesn't take more than 3 years to complete and you know the outcome before you've even started. If one would listen to the general public what projects are worth funding it would just reinforce the problems: Most people want to see immediate and tangible outcomes of their investments. That this doesn't work for basic research is exactly why so much of it is tax funded.

It adds to this that the crowdfunding approach puts at advantage research that can be easily decorated with pictures and produced in a video. If your project is about finding the best milk substitute for orphaned kittens it will score better than, say, the kappa-deformation of the Poincare Hopf algebra on discrete non-metric spaces in arbitrary dimensions. That might seem like an extreme example, but it isn't hard to predict that most of mammalian biology and medicine would produce better videos and more catchy pitches than mathematics or theoretical physics. And alien biology of course... Click to read whole comic.

Via Bad Astronomy. I didn't find it particularly funny. It's more in the category sad but true.

Giving to charity is much more common in North America than it is in Europe. An oversimplified summary is that Europeans pay more taxes and believe in representative democracy while Americans like the idea to distribute the money themselves and mistrust their electees. So it isn't much of a surprise most of the examples above are US based.

There is no generally right or wrong way to invest in non-profit organizations; it depends on the aim. Yes, donors chose. But the big question is how well they chose to invest their money and if not channeling of investment through expert committees puts money to use better. There are some cases where crowds are wise and chose wisely. And while the right circumstances for crowds to make wise decisions are still a subject of research, it seems to be clear that one needs a well-posed and concrete question to begin with. In addition, one person's decision shouldn't be affected by the choices others have made. Otherwise the rich will just get richer. These are conditions not fulfilled when it comes to judging on the promise of a research project.

Without knowing the status of a research field one has no way of telling if an investment is good, and this is not a knowledge one obtains by browsing a video collection. Or look at medicine with its many "orphan diseases" - not diseases of orphans, but all those illnesses you have never heard of because no Hollywood star fell victim to it. Where you invest best should depend on how promising a research proposal is, and that potentially in the course of some centuries. Not on what's currently on TV.

I am not saying the general public is dumb. I am talking about a lack of knowledge here, and a lack of time to obtain that knowledge. Pop sci gets you only so far.

Via Moshe. I did find that one hilarious indeed.

Then there is the problem that slopes may be slippery. I can just see us ending up in a position where scientists are expected to use crowdfunding for their research. And that will not only be an ineffective distribution of money because said crowd is prone to like projects for the wrong reasons, but also because it takes up more of the researchers' precious time for producing a fancy proposal that will appeal to the public. And then somebody still has to do the reviewing.

Summary: Crowdfunding science is a good idea to add additional support to underfunded missions or to enable small projects. It is not a good idea to draw upon the public opinion to fund research projects from scratch. It might appear as if public money is put to good use, but that use is likely to be very inefficient and misdirected and doesn't actually solve any systemic problem. If you must, go occupy Wall Street, vote, and make sure your taxes are put to good use.