Déjà vu

Last week, on the workshop in Bonn, I was in for a nasty surprise. Sitting there, listening to one talk after the other about black holes, I saw pictures reappear that I had made. Four different pictures of mine, in four different talks. All without picture credits. When I told the speakers later that they've been using a picture that took me in some cases hours to make without even putting my name below it, they apologized. One shrugged shoulders and said "It came up in Google." I checked that, it did come up when doing a Google image source for "Black Hole Evaporation," the source being my home page. I'm not surprised by this, my homepage has always been well indexed by Google. Apparently I was expecting too much when thinking people could at least look at the front page and find my name.

I will admit that I am very dismayed by this. Yes, I too sometimes do use other people's figures and plots in my talks, but I usually add a source, if possible to find. It's more complicated with photos, who will typically appear in so many copies on some dozen websites that it's next to impossible to find out who originally took the photo. In any case, some of the pictures I saw reappearing in those talks I don't even hold the copyright on. They were published in one of my papers, and with that the copyright went to the publisher.

I don't mind at all if people use my pictures, otherwise I wouldn't upload them to my website. I receive the occasional email from somebody asking if they can use one or the other for a talk or a paper and I always say yes. (I once was asked for a picture to be reprinted in a popular science book, but when the publisher of my picture was asked for the reprint permission they said no for reasons I still don't understand.) But of course I do expect that people add at least my name below it. It has previously happened that I saw pictures of mine reappear, this one showing an evaporating black hole seems to be the favorite



but that workshop convinced me to add my name in a corner of all these pictures. Sure, one can cut it out, but it takes a deliberate effort.

This also reminds me that I once received a paper for peer review. It was written in dramatically bad English, then all of a sudden there were two paragraphs that weren't only readable but sounded eerily familiar. A quick check confirmed my suspicion that it was an introduction from one of my own papers. They had cited my paper somewhere, but it was by no means clear they had copied half a page from it. Again, my paper was published, the copyright was with the publisher. The paper I reviewed wasn't only badly written but also wrong, so it didn't get published. However, I later wrote to the authors making it very clear that this is not an appropriate way to cite. They either mark it as a quotation, or they rewrite it. They apologized and then rearranged a few words here and there. I know other people who have made exactly the same experience with one of their papers.

I find it very worrisome that more and more people make so unashamedly use of other's work without even thinking about it. My mother is a high school teacher and as a standard procedure she'll have to check every essay for whether it's been copied elsewhere. Evidently, there's still kids stupid enough to try nevertheless. I know these checks are being done in many other places too, there's even software for it so you don't have to Google every sentence manually. An extreme case that I know of was a PhD candidate who had copied together half of his thesis from other people's review articles, including equations, references and footnotes. He did cite the papers he used, but certainly didn't mark the "borrowed" pieces as quotations.

It is clear that when thousands of people write introductions to the same topic, then many of them will sound quite similar. I also understand that when you find a nice picture for your talk online it seems superfluous to spend time yourself on what Google gives it to you on a silver plate. Certainly you have better things to do than making a pictures for your talk, right? But what you're doing is simply using someone else's effort and selling them as your own. So next time, spend the three seconds and check whose homepage you've been downloading your pictures from.




And here's a recent copyright story that I found hilarious "Greek man sues Swedish firm over Turkish yoghurt pic"

"A Greek man has sued a dairy firm in southern Sweden after his picture ended up on a Turkish yoghurt product. The man whose picture adorns the Turkish yoghurt product, manufactured by Lindahls dairy in Jönköping, argues that the company does not have permission to use his image [...]

The man, who lives in Greece, was made aware of the use of his picture on the popular Swedish product when an acquaintance living in Stockholm recognized his bearded friend [...]

In his writ the man has underlined that he is not Turkish, he is Greek, and lives in Greece, and the use of his picture is thus misleading both for those who know him and for buyers of the product.

Lindahls dairy has expressed surprise at the writ and argues that the image was bought from a picture agency [...]"

The left-handed Piano

As a left-hander, I have an early hands-on experience with the concept of chirality, or handedness: It can be quite difficult to cut a piece of paper with the left hand using standard scissors; the blades usually do not close precisely, resulting in a frayed cut. And of course, scissors with modern, "ergonomically-formed" handles cannot be used with the left hand in the first place.

There is a small niche market for all kinds of chiral partners of standard right-handed everyday products and tools: left-handed scissors, left-handed can-openers, left-handed pencil sharpeners. However, I do not utilize any of them, and use standard instruments with the right hand instead.

Today, I heard on the radio about something really amazing on the market on left-handed products: There are left-handed pianos!

Invented by Geza Loso, musician, piano teacher, left-hander and father of three left-handed kids, they are exact mirror images of usual pianos, with the pitch rising from the right to the left. As Geza Loso explains on his website: For the first time left-handed people receive a real chance to learn how to play the piano on an adequate instrument. Left-handed people would basically use their right hand to accompany and the skilled hand to handle the main functions of a piano-play, to play the melody. This is very decisive for every artistic interpretation.

The left-handed piano will be distributed by the Leipzig piano-manufacturing company Blüthner. Chief executive Christian Blüthner doesn't expect a big commercial success, but thinks that the left-handed piano demonstrates his company's inventiveness. And I am wondering if my career with the piano may have have been longer than a couple of lessons if the instrument would have been left-handed.

Hello from Bonn

Stefan and I, we are currently in Bonn for a workshop on "Black Holes in a Violent Universe." Bonn is the former German capital and a quite charming city, though not what you'd expect from a capital. So probably a good thing Berlin has taken over the burden. Germany is collectively in a good mood these days since the Germans won Friday's soccer game, and everybody is looking forward to Sunday's game.

We're staying in a small hotel near the river Rhine. Needless to say, our room is on the 4th floor without elevator. On the other hand, we have a small roof patio. And here's what we found looking out of the window on the side opposite the patio: A small staircase leading to a platform (the top of the downstairs windows) with railing. That little walkway ends then, leaving you with the only option of a 4 floors' jump down on the paved street. I was thinking it might be the emergency exit, but the evacuation plan on our door points another direction. So not sure what this is. An invitation for suicide? A diving platform in case the river floods?




My talk about the black hole information loss problem went very well (slides here). I wish you all a great weekend.

Guestpost: Marcelo Gleiser

[A month ago, I was at a workshop at Perimeter Institute and I reported on a talk by Marcelo Gleiser. Marcelo's talk was very interesting and thought-stimulating. It touched upon very many different topics, from the process of knowledge discovery to the question of whether we should be searching for a fundamental theory of everything. In my post I expressed my opinion that of course believing in a theory of everything, if you take the name literally, is religion not science because if we had one we would never know if not one day we'd discover something that the theory would not explain. But the whole question of whether it exists is somewhat besides the point, the actual question (for me, the pragmatist) is what is a promising approach to take that will lead to progress.

Marcelo has now written a reply to some of the points that came up in my post and the comments, and to some other reactions that he got. This reply can also be found at his blog 13.7.]

To Unify Or Not To Unify: That Is (Not) The Question

My latest book, A Tear at the Edge of Creation, came out in the US early April. In it, I present a critique of some deeply ingrained ideas in physics. In particular, I examine the question of unification and the search for a theory of everything, arriving at conclusions that—judging from some of the reactions I’ve been getting in lectures and in various blogs around the world—are shocking to many people.

Of course, I welcome criticism and skepticism. We are used to this in scientific debates. What’s surprising to me, and perhaps alarming, is the speed with which superficial commentary in the blogosphere quickly escalates into complete misunderstanding of what it is that I am saying and why. So, I think the time is ripe for sketching a reply, even though the space here won’t do justice to the details of the argument. I do hope, however, that this will at least inspire critics and skeptics to actually read the book and judge for themselves and not through a few lines on a blog post.

Among other things, in the book I suggest that the notion of a final theory, that is, a theory that encompasses complete knowledge of how matter particles interact with one another, is impossible. First, note that “final theory” here deals only with fundamental particle physics. Any claim that physical theories could be complete in the sense of describing (and predicting) all natural phenomena, including why you’re reading this, shouldn’t be taken seriously.

First, we must consider if a complete theory of matter does exist. Second, assuming it does, if we can ever get to it. The first question is quite nebulous. We have no way of knowing if such a complete theory exists. We don’t even know what a “complete” theory is. You may believe it does and spend your life searching for it. That’s a personal choice. Or, like most physicists, you may believe this is nonsense, more metaphysics than physics. The second question, though, is tangible. Can humans achieve complete knowledge of the subatomic world?

To answer this question, we must look at how science actually works. In a post at her blog Back Reaction, physicist Sabine Hossenfelder expressed her surprise at my statement that it took me 15 years to figure out that the notion of a final theory is faulty. Sorry Sabine, I guess old habits are hard to break. At least, I did see the light in the end. Happily, she agreed with my basic argument, that since what we know of the world depends on our measurements of the world, we can never be sure that we arrived at a final explanation: as tools advance, there is always room for new discoveries. Knowledge is limited by discovery.

I go on to describe how the unifications that we have achieved so far, beautiful and enlightening as they are, are approximations and not “perfect” in any sense. The electroweak theory, a unification of the electromagnetic and the weak nuclear forces, is not a true unification but a mixing of the two interactions. Even electromagnetism, the paradigm of unification, only works flawlessly in the absence of sources. To be a truly perfect unification, objects called magnetic monopoles would have to exist. And even though they could still be found, their properties are clearly very different from the ubiquitous electric monopoles, e.g. point-like particles like electrons. We have partial unifications and we should keep on looking for more of them. This is the job of theoretical physicists. The mistake is made when symmetry, a very useful tool in physics, is taken as dogma.

I don’t agree with Sabine when she says that it doesn’t matter what you believe in as long as the search “helps you in your research.” I think beliefs are very important, and to a large extent drive what it is that we are searching and the cultural context in which research is undertaken. Wrong beliefs can have very negative consequences. And can keep us blind for a long time.

So, one of the points I make is that science is a construction that evolves in time to expand our body of knowledge through a combination of intuition and experimental consensus. There is no end point to it, no final truth to arrive at.

Now, here are some of the things that have been said about my arguments:

“Marcelo is disillusioned with unification; he has closed up his mind to string theory; he couldn’t find a Theory of Everything and now thinks no one can find one as well; he’s just frustrated; he doesn’t understand the role of symmetry in physics (!); he’s timing is bad because the LHC will be revealing new physics.” George Musser, at a Scientific American blog post wrote “My own reaction was that although it’s useful to caution against clinging to preconceived ideas about a final theory, Gleiser was too insistent on seeing the glass of physics as half-empty.” Musser goes on to say how much we do know about Nature and how much of that is due to the fact that simple laws govern natural phenomena.

It’s true that Musser (and Sabine) were basing their comments on a lecture I gave recently at the Perimeter Institute and not on my book (you can watch the video here). Even so, as I tried to make clear in my text, I would never put down the remarkable achievements of science and much less be foolish to say that there are no patterns and symmetries in Nature! After all, that is how science works, by searching for simplifying explanation of natural phenomena. Having the LHC turned on and able to probe physics at energies higher than ever before is a very exciting prospect.

The same general defensive zeitgeist was echoed by Neil Turok, the current director of the Perimeter Institute. We recently participated in a televised debate hosted by TV Ontario on Stephen Hawking’s ideas. We were a group of six physicists, hosted by Steve Paikin and had a great time. But at the end, when I made my arguments about final unification and the limits of knowledge, Turok accused me of pessimism!

If anything, my book is a celebration of the human mind and all that we have achieved in such a short time. The fact that I point out that science has limitations doesn’t detract from all of its achievements. Or from all that lies ahead.

I’m not disillusioned for not having found a TOE or for believing it doesn’t exist. I’m actually relieved!

The reactions that I have encountered only reinforce my point, that there is great confusion these days about the cultural role of science and scientists. Science is not a new form of religion, scientists are not holy men and women, and we don’t have or can have all the answers.

As I wrote in Tear at the Edge of Creation, “Human understanding of the world is forever a work in progress. That we have learned so much, speaks well of our creativity. That we want to know more, speaks well of our drive. That we think we can know all, speaks only of our folly.”

Hopefully, this acceptance of our perennial ignorance won’t be interpreted as an opening to religion and supernatural explanations. Let me make my position clear: behind our ignorance there is only the science we still don’t know.

Closer to Truth...

Recently, I coincidentally came across the website of a TV-show called "Closer to Truth," that I frankly had never heard of before. Amazingly enough the website features a large selection of interviews with well known scientists, nicely ordered into short videos taking on specific topics.

There is Lisa Randall (eg Are there extra dimensions?), Nima Arkani-Hamed (eg Why is Quantum Gravity so Significant?), Juan Maldacena (eg Why Black Holes are astonishing), Lee Smolin (eg What do Black Holes and Dark Matter reveal?), Roger Penrose (eg Is Mathematics Invented or Discovered?), Fotini Markopoulou (eg What is a Theory of Everything?), Paul Davies (eg Do Science and Religon conflict?), and many more... Enjoy!

Interna

The summer solstice is near and days here in Stockholm are getting longer and longer. The other day I woke up early and, looking out of the window, saw that it was dawning already. Or so I thought. The clock revealed that it wasn't the dawn I was seeing, but that the sun hadn't even set. My biorhythm seems to be a little confused these days.

Along with midsummer also the long awaited wedding of Sweden's Crown Princess Victoria is coming closer. Tomorrow Victoria will exchange I-do's in Stockholm Cathedral with her former personal trainer Daniel Westling. It's a giant marketing event: The Swedes have declared Stockholm's airport Arlanda the "Official Love Airport 2010" and the two weeks before the wedding we had to endure the "LOVE Stockholm 2010," a "two-week festival of love, right in the centre of Stockholm." You can buy postcards and posters of the happy couple in every supermarket here, together with loads of blue-yellow decorations. Busy cityworkers have planted yellow and blue flowers all over the place. Just the weather isn't really playing along, today it's rainy at 17° C.

My Swedish isn't good enough to actually understand the traffic report on the radio, but I understand as much as a long list of streets separated by stängt stängt stängt stängt (closed). I for certain will stay as far away as possible from the city center tomorrow. If your national TV station doesn't broadcast the event, you can follow the wedding ceremonies live tomorrow via SVT. I think it's great the two get married tomorrow because that way I was able to grab a slot for the laundry room on Saturday morning.

Next week, I'll be on a short trip to Bonn for a workshop on quantum black holes, where I'll give a talk about my paper with Lee on the black hole information loss. I wish you all a lovely weekend :-)

Science Metrics

Nature has a very interesting News Feature on metrics for scientific achievement, titled Metrics: Do metrics matter? The use of scientific metrics is a recurring theme on this blog. I wrote about it most recently in my post Against Measure.

The main point of my criticism on science metrics is that they deviate researchers' interests. It is what I refer to as a deviation from primary goals to secondary criteria. Here, the primary goal is good research. The secondary criteria are some measures that for whatever reason are thought to be relevant quantifiers for the primary goal. The problem is that, even if the secondary criteria have initially had some relevance, their implementation inevitably affects researcher's own assessment of what success means and leads them to strive for the secondary criteria rather than the primary goal. With that, the secondary criteria become less and less useful since they are being pursued as an end in itself. Typical example: number of publications. In principle not a completely useless criterion to assess a researcher's productivity. But it becomes increasingly less useful the more tricks scientists pull to increase the number of publications instead of focusing on the quality of their research.

Note that for a deviation of interests to happen it is not necessary that the measures are actually used! It is only relevant that researchers believe they are used. It's a sociological effect. You can cause such believes by simply doing much talk about science metrics. The better known a measure is, the more likely people are to believe it has some relevance. It is a well known fact about human psychology that people pay attention to what they hear repeatedly.

Now Nature did a little poll asking readers how much they believe science metrics are used at their institution for various purposes. 150 readers responded; the results are available here. They then contacted scientists in administrative positions at nearly 30 research institutions around the world and asked them what metrics are being used, and how heavily they are relied on. In a nutshell the administrators claim that metrics are being used much less than scientists believe they are.

"The results suggest that there may be a disconnect between the way researchers and administrators see the value of metrics."

While this is an interesting suggestion, it is not much more than a suggestion. It is entirely unclear whether the sample of people who replied to the poll had a good overlap with the sample of administrators being asked. By such a small sample size the distribution of people in both groups over countries matters significantly. It remained unclear to me from the article whether in their contacting of institutes they have made sure that the representation of countries is the same as that of the poll's participants, and also if the distribution of research fields is the same. If not, the mismatch between the administration and the researchers might simply show national differences or differences between fields of research. Also, it is conceivable that people who filled out the questionnaire had some concerns about the topic to begin with, while this would not have been the case for people contacted. It did not become clear to me how the poll was publicized.

In any case, given what I said earlier, we should of course appreciate the suggestion of these results. Please do not believe that science metrics matter for your career!

Why do people get tattooed?

Last night, I had a weird dream. A white haired man with a long beard insisted on tattooing my shoulder. I couldn't get him to drop his plans, so he started punching. I asked him what the image will be. “I'm doing a circle,” he said. He continued his circle but when he finished it didn't close. “Now I have to walk around with a stupid non-closing circle!” I complained and he poured his ink over me. Then I woke up.

You're welcome to analyze this dream, but not allowed to use the words “string” and “loop.”

If you read science blogs frequently you'll probably have come across one or the other posting of a science related tattoo. (See eg here for a nice compilation.) It always leaves me wondering what drives people to do that. It's one of these emerging social and cultural trends that are so complex even the people doing it don't know why they're doing it. It is, from an evolutionary perspective, very interesting what weird behaviors intelligent creatures can develop in large groups. My attempt to understand humans recently brought me across the paper “Modifying the body: Motivations for getting tattooed and pierced” (Wohlrab, Stahl and Kappeler, Body Image 4 (1007) 87). They start with an interesting historical summary (please see paper for references):

“[Tattooing and body piercing] have a long history and are well known from various cultures in Asia, Africa, America, and Oceania. There is also evidence for the prevalence of tattoos in Europe, dating back over 5000 years. Although the appearance of tattoos and body piercings varied geographically, they always possessed a very specific meaning for the particular culture. Piercings were often used in initiation rites, assigning their bearer to a certain social or age group, whereas tattoos were utilized to signal religious affiliations, strength or social status. In Europe, the practice of tattooing was predominant among sailors and other working class members from the beginning of the 20th century onwards. Later on, tattoos assigned affiliations to certain groups, such as bikers or inmates. In the 1980s the punk and the gay movement picked up invasive body modification, mainly as a protest against the conservative middle class norms of society.

Until the 1990s, body modifications remained a provocative part of various subcultures. In the last decade tattoos and piercings have increased tremendously in popularity, rising not only in numbers but also involving a broader range of social classes.”

Thus, historically tattoos seem to predominantly have been used to signal affiliation to or sympathy with a group. The paper is basically a literature survey, and the authors then identify ten motivations for getting tattooed that have been studied. These are: 1) Beauty, art and fashion 2) Individuality 3) Personal narrative 4) Physical endurance 5) Group affiliation and commitment 6) Resistance 7) Spirituality and cultural tradition 8) Addiction (to obtaining the tattoo) 9) Sexual motivation (in the case of tattoos: expressing affectation or emphasizing the own sexuality) 10) No specific reason (eg under the influence of drugs).

For what science tattoos are concerned, I think we can forget about the last category. It seems quite unlikely to me the average guy on the street will get drunk and wake up the next morning with the Wheeler-DeWitt equation on his shoulder. For what point 4) is concerned, I think we can leave this aside as well. I don't think the physical endurance is higher for scientific motives. Unless maybe there's a mistake in the equation.

For what sexual motivations are concerned, it is in this context interesting to draw upon a recent survey, conducted in Germany (sample size approximately 2500, as reported in “Machen Tattoos sexy?” forschung SPEZIAL. Das Magazin der Deutschen Forschungsgemeinschaft, 2/07, 22-25). More than 10% of men and more than 8% of women were tattooed. The age range that currently dominates the wedding market (18-36 years) has the largest fraction of tattooed people. Men are more likely to be tattooed on arms and legs, whereas women prefer places that can easily be covered by cloths: back, belly, bottom. Not so surprisingly, men prefer designs with skulls, weapons and such, whereas women prefer flowers and animals. Maybe the most interesting fact though is that while only 8% of women had a tattoo, 56% of the participants with a tattoo had a partner who was also tattooed. So there's clearly some matching going on there. Another study in which participants were shown images of tattooed people revealed that both women and men judged people with tattoos to be more “aggressive” and “dominant.” Maybe for some, that is a desired effect?

Needless to say, all that reading didn't really explain why people want to have an equation on their arm. I can relate to the beauty/fashion motivation to some extend, but I suspect that if your fashion statement are Maxwell's equations you'll get more confused than admiring looks. I suppose the most likely motives are thus personal narrative and showing group affiliation and commitment. Or maybe we're seeing an attempt of resistance to anti-intellectualism? Not to mention that you can upload the photo to your blog and collect cheers. As for myself, I've fleetingly considered getting tattooed once or twice, but my tastes are at the best metastable and whatever the design, I'd probably get fed up with it after a few months, so tattoos are not for me.

Anyway, it is sometimes very refreshing to read an article in a journal I had never heard of before like Body Image. The most amusing part was this sentence from the abstract, right out of the ivory tower:

“[A] profound understanding of the underlying motivations behind obtaining tattoos and body piercings nowadays is required.”

Sure, I mean, unstable financial systems are ruining the lives of millions of people, climate change is about to erode the basis of many economies posing a threat for global political and social stability, each year about 5 million people still die because they don't have enough to eat, but what's really required is a profound understanding of why people punch needles through their nipples. If you replace “motivations behind” with “structure of” and “obtaining tattoos and body piercings” with your favourite physics term, I'm sure you'll find the same sentence in a significant fraction of arxiv papers...

Book review: From Eternity to Here by Sean Carroll

From Eternity to Here: The Quest for the Ultimate Theory of Time
By Sean Carroll
Dutton Adult (January 7, 2010)

Most of you will know Sean Carroll, who blogs at Cosmic Variance. Sean is a Senior Research Associate at CalTech and his research focuses on cosmology, general relativity and the standard model, as well as extensions thereof. He has written a textbook on General Relativity, and the lecture notes that gave rise to the book are available online. I've met Sean a few times, he's an interesting person and gives great talks. Sean has a special interest in the arrow of time, and that is also the topic of book “From Eternity to Here.” The arrow of time is, in a nutshell, the question why the past is different from the present.

I bought the book for three reasons. One is that for many years I've been using the PDF version of his lecture notes as a handy quick reference when on travel and had a bad consciousness for never buying the book. The second one is that from reading Sean's blog I know he writes well. The third reason is that adding a second book to the order rendered delivery free.

“From Eternity to Here” is a very well written book that communicates a lot of science, both textbook science and contemporary science, while at the same time being amazingly accurate. The biggest part of the book - all but the last chapter - is dedicated to accurately framing the question. Why is it interesting to ask why the past was what it was? What exactly is it that we don't understand? How do we get a grip on the problem? For this, Sean covers first of all the second law of thermodynamics, then special relativity, general relativity, cosmology, quantum mechanics, black hole physics, and finally inflation and the multiverse. In the last chapter, he then discusses possible solutions to the question he has posed and puts forward his own solution as the most plausible one. Along the way he scratches on topics like the vacuum energy, structure formation, the AdS/CFT duality and magnetic monopoles.

Sean is very careful with distinguishing between established science and unconfirmed speculations. The only glitch is the section on the holographic principle where he fails to point out that there is no experimental evidence for such a feature of Nature to be true in all generality. I am somewhat sick of being misinterpreted on this point so let me be very clear here. All I am saying is that, absent experimental evidence, scientists should be very careful with what they put forward as a true description of Nature. Theoretical evidence can very easily be biased simply because a topic that attracts attention may mount one-sided “evidence.” This can never replace actual tests of a hypothesis. The holographic principle certainly does not rest on the same basis as ΛCDM or the Schrödinger equation and I wish its status had been framed more clearly. Anyway, Sean needs the holographic counting of degrees of freedom for the rest of his argument.

I was very pleased that Sean's explanations of physical concepts are not as superficial and vague as one frequently finds in popular science books. He does not shy away from the phase space, using logarithms, and discusses the amplitude of the wave function. The chapter on quantum mechanics however somewhat suffers from the overuse of cats and dogs. The book has plenty of footnotes with additional explanations, and offers many references so that the interested reader will easily be able to find the relevant keywords and dig deeper, should they wish so. On several occasions I took a note that Sean had forgotten to point out a specific assumption that entered his argument or left out some exceptions. In every single case, these points were later addressed, so I am left with nothing to complain about.

I personally don't have a large interest in the topic and don't care very much about the whole discussion. I think the question is ill-posed and when we have a better understanding of quantum gravity we'll see why. Sean's book didn't succeed in increasing my interest. Nevertheless, it was a pleasure to read. Sean has a good sense of humor, but doesn't overdo it. The story he tells is also well embedded into its scientific history and I learned a thing or two here that I hadn't known before. Both the historical and the philosophical aspects however play a secondary role and don't take over the scientific discussion. All together, the book is very well balanced and a recommendable read. It has something to offer for anybody who has an interest in modern cosmology and/or the arrow of time. I'd give this book 5 out of 5 stars.

---

From January through April, Sean offered a book club at his blog, each weak discussing another chapter. You might find this a useful addition to the book itself.

Perimeter Institute is looking for a Scientific IT specialist

Two years ago, I organized a conference on Science in the 21st Century, focusing on topics at the intersection on science, society and information technology. (I wrote about the conference here, a summary is here and a brief write-up of my own talk is here.) There are three aspects to the changes that the use of information technologies are bringing to science. One is the improving communication with the public - this blog is an example for such a change. The second one is that advances in hard- and software allow us to better understand the process of knowledge discovery and the dynamics of the scientific communities itself - the Maps of Science are an example for this. The third aspect, and probably the one most interesting for the scientist at work, is the development of new tools that support research and researchers in their every day work.

As I learned the other day, Perimeter Institute is now looking for a person who works at exactly this intersection. The job description reads as follows:

The Perimeter Institute for Theoretical Physics (PI) is looking for a Scientific IT specialist -- a creative individual with experience in both scientific research and information technology (IT). This is a new, hybrid, research/IT position within the Institute, dedicated to helping PI’s scientific staff make effective use of IT resources. It has two clear missions. First, to directly assist researchers in using known, available IT tools to do their research. Second, to uncover or develop cutting-edge IT resources, introduce and test them with PI researchers, and then share the things we create and discover with the worldwide scientific community.

By "tools", we mean almost anything. Coding techniques are an obvious example. Collaboration and communication technologies are another: tools for peer-to-peer interactions (such as skype), virtual whiteboards, video conferencing tools, platforms for running virtual conferences (that can do justice to talks in the mathematical sciences), and novel ways of presenting research results such as archives for recorded seminars, blogs, and wikis. Further examples include tools for helping researchers organize information (e.g., specialized search engines and filtering schemes), and end-user software that facilitates bread-and-butter scientific activities like writing papers collaboratively, preparing presentations, and organizing references.

We are seeking a person who brings an independent and ambitious vision that will help define this vision. The job is as yet quite malleable in its scope and duties! We're looking for someone who is inspired by the possibility that new IT tools can improve or perhaps even revolutionize the way that physics research is done, and someone who can take full advantage of a mandate to create and implement that vision.

Some Duties and Responsibilities:

- Act as a knowledge broker among Researchers. That is, find and test new programs and practices, advertise them, and be prepared to train others in their use.

- Participate in the creation of a high quality “standard" Researcher IT environment (desktop hardware, software set-up), built from a mix of open source software and popular commercial packages.

- Help with High Performance Computing demands.

- Maintain expert level knowledge in the use of the main packages used by Researchers, including Mathematica, Maple, LaTex, etc.

For the official job ad, go here.

[Via Rob Spekkens]. The deadline for applications is Friday, July 2, 2010. The Albert Einstein Institute in Potsdam meanwhile offers an almost identically sounding position. I've been told PI was first, but their posting is not dated.

I very much like this development. My requirements on IT staff these days are however very modest. I am happy when the printer spits out my paper without chewing up some pages or leaving them blank. My biggest wish would be not a virtual whiteboard but an actual whiteboard with a plugin to my computer so I could use the board for equations and figures during a skype call. The equations are usually cumbersome but still doable, in the worst case by typing them in LaTex into the chat interface. But diagrams are a disaster. Drawing with a mouse yields no sensible results and the drawing pads that I've tried weren't too convincing either, even neglecting the problem on how to incorporate them into the call. On occasion I've thus drawn on a paper and held it into the camera. This however only works for figures with few details and necessitates plenty of additional explanations.

What is the software or hardware you dream of for your research life?

Diamonds in Earth Science

To clarify the situation, experiments would need to push above 120 Gigapascal and 2500 Kelvin. I [...] started laboratory experiments using diamond-anvil cell, in which samples of mantle-like materials are squeezed to high pressure between a couple of gem-quality natural diamonds (about two tenths of a carat in size) and then heated with a laser. Above 80 Gigapascal, even diamond—the hardest known material—starts to deform dramatically. To push pressure even higher, one needs to optimize the shape of the diamond anvils's tip so that the diamond will not break. My colleagues and I suffered numerous diamond failures, which cost not only research funds but sometimes our enthusiasm as well.
(From The Earth's Missing Ingredient)

But in the end, Kei Hirose and his group succeeded in subjecting a small sample of magnesium silicate to the pressure and temperature that prevails in the lower Earth's mantle, about 2700 kilometer below our feet.

Planet Earth has an onion-like structure, as has been revealed by the analysis of seismological data: There is a central core consisting mostly of iron, solid in the inner part, molten and liquid in the upper part. On top of this follows the mantle, which is made up of silicates, compounds of silicon oxides with magnesium and other metals. The solid crust on which we live is just a thin outer skin.

The lower part of the mantle down to the iron core was long thought to consist of MgSiO₃ in a crystal structure called perovskite. However, seismological data also revealed that the part of the mantle just above the CMB (in earth science, that's the core-mantle boundary, not the cosmic microwave background... ) somehow is different from the rest of the mantle. This lower-mantle layer was dubbed D″ (D-double-prime, shown in the light shade in the figure), and it was unclear if the difference was by chemical composition or by crystal structure.

As Kei Hirose describes in the June 2010 issue of the Scientific American, his group started a series of experiments to study the properties of magnesium silicate at a pressure up to 130 Gigapascal (water pressure at an ocean depth of 1 kilometer is 0.01 GPa) and a temperature exceeding 2500 Kelvin ‒ the conditions expected for the D″ layer of the lower mantle.

To achieve such extreme conditions, one squeezes a tiny piece of magnesium silicate between the tips of two diamonds, and heats up the probe by a laser. The press used in such experiments is called "laser-heated diamond anvil cell".

(From "Laser-heated diamond anvil cell technique: double sided heating with multimode Nd:YAG laser" by G. Shen, H.K. Mao, and R.J. Hemley.)

The figure shows the core of a diamond anvil cell: The sample to be probed is fixed by a gasket between the tips of two diamonds. The diameter of the tips is about 0.1 millimeter, so applying a moderate force results in huge pressure.

Diamonds are used because of their hardness, but they have the additional bonus of being transparent. Hence, the probe can be observed, or irradiated by a laser for heating, or x-rayed for structure determination.

The diamonds are fixed in cylindrical steel mounts, but creating huge pressure does not require huge equipment: The whole device fits on a hand! (Photo from a SPring-8 press release about Kei Hirose's research.)


Actually, the force on the diamond tips is applied in such a device by tightening screws by hand.

In the experiment, the cell was mounted in a brilliant, thin beam of x-rays created by the SPring-8 synchrotron facility in Japan. This allows to monitor the crystal structure of the probe by observing the pattern of diffraction rings.

It was found that under the conditions of the D″ layer of the lower mantle, magnesium silicate forms a crystal structure unknown before for silicates, which was called "Post-Perovskite". The formation of post-perovskite in the lower mantle is a structural phase transition of the magnesium silicate, and this transition can explain the existence of a separate the D″ layer, and many of its peculiar features. It also facilitates heat exchange between core and mantle, which seems to have quite important implications for earth science.

And here is the heart of the experiment (from the "High pressure and high temperature experiments" site of the Maruyama & Hirose Laboratory at the Department of Earth and Planetary Sciences, Tokyo Institute of Technology) ‒ a diamond used in a diamond anvil pressure cell:


High-quality diamonds of this size cost about US $500 each.

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• Motohiko Murakami, Kei Hirose, Katsuyuki Kawamura, Nagayoshi Sata, and Yasuo Ohishi: Post-Perovskite Phase Transition in MgSiO₃, Science 304 (2004) 855-858. (PDF)
• Kei Hirose, Post-perovskite Phase Transition in MgSiO₃ (PDF, from SPring-8 Research Frontiers 2004.

Impressions from the PI workshop on the Laws of Nature

As you know, 2 weeks ago I was at Perimeter Institute for the workshop on the Laws of Nature: Their Nature and Knowability. It was a very interesting event, bringing together physicists with philosophers, a mix that isn't always easy to deal with.

People (them)

On the list of participants, you'll find some well known names. Besides the usual suspects Julian Barbour and Lee Smolin, Paul Davies was there (though only for the first day), Anthony Aquirre (the event was sponsored by FQXi) and of course several people from PI and the University of Waterloo. In my previous post, I already wrote about Marcelo Gleiser's talk. Marcelo is from Brazil, and he is apparently well known there for his popular science books (which was confirmed by Christine in an earlier post.) I had frankly never heard of him before. I talked to him later over dinner, and he told me he writes for a group blog called 13.7 together with, among others, Stuart Kauffman who is also well known for his popular science books. (13.7 is the estimated age of the universe in billion years. What will they do if that number gets updated?)

Another interesting name on the list of participants is Roberto Unger, who is a well-known Brazilian politician and besides that a professor for law at Harvard Law School, and author of multiple books on social and political theory. He apparently has an interest not only in the laws of societies, but also in the laws of Nature*. And finally let me mention George Musser was also at the workshop. George writes for Scientific American and is author of The Complete Idiot’s Guide to String Theory. He turned out to be a very nice guy with the journalist's theme "I want to know more about that."

Talks (their)

Now let me say a word about the talks. First, and most important, all the talks were recorded and are available on PIRSA here. The talks on the first day were heavily philosophical. I will admit that I often have problems making sense of that. Not because I don't have an interest in philosophy, but because one frequently ends up arguing about the meaning of words which is, at the bottom of things, a consequence of lacking definitions and thus a waste of time. Yes, my apologies, I'm, duh, a theoretical physicist with some semesters maths on my CV. If I don't see a definition and an equation, I get lost easily. In some cases it seems the philosophers imply some specific meaning that they just never bother to explain. But in other cases they'll start arguing about it themselves, and that's when I usually zoom out wondering what's the point in arguing if they don't know what they're arguing about anyway.

The most interesting event on the first day was arguably Lee Smolin's and Roberto Unger's shared talk "Laws and Time in Cosmology". Let me add that I've heard Smolin talking about the "reality of time" several times and I still can't make sense of it. The problem I have is simply that I don't know what he's talking about. This recent talk didn't change anything about my confusion, but if you haven't heard it before, you might find it inspiring. Unger's talk is very impressive on the rhetorical side. Unfortunately, it made even less sense to me than Lee's talk. For all I can see, there's no tension neither between a block-universe and a notion of simultaneity nor between a block-universe and causality, as I think I heard Unger saying (thus my question in the end). Point is, I don't understand the problem they're attempting to address to begin with. I see no problem. As Barbara Streisand already told us "Life is a moment in space" and "In love there is no measure of time." Consequently, a universe where time is real must be loveless. I don't like that idea.

On that note, let me recommend Julian Barbour's talk "A case for geometry". Julian is a charming British guy and he has his own theory of a lovely, timeless universe. I don't buy a word of what he says, but his talk is very accessible and fun to listen to. It makes your head spin what he's saying, just try it out, it's very intriguing. I am curious to see how these ideas will develop, it seems to me they might be on the brink of actually making predictions. (A somewhat more detailed explanation of his ideas is here, audio becomes audible at 3:30 min.)

On the second day, we had several talks discussing concrete proposals for how one could think of the laws of Nature off the trodden path. You probably won't be surprised to hear that one of the suggestions is that of "Law without Law: Entropic Dynamics" by Ariel Caticha. It is not directly related to Erik Verlinde's entropic gravity, but certainly plays in the same corner of the room: exploiting the possibility that fundamentally all our dynamics is simply a consequence of the increase of entropy. Ariel's talk however isn't really recommendable, it sits on a funny edge between too many and too few details.

Another approach is Kevin Knuth's who put forward in his talk "The Role of Order in Natural Law" the idea that on the basis of all, there's order - in a well-defined mathematical sense. I can't avoid the impression though that even if this worked out to reproduce the standard model, it would merely be a reformulation. Kevin's talk was basically a summary of this recent paper. And Philip Goyal gave a very nice talk on "The common symmetries underlying quantum theory, probability theory, and number systems." I have a lot of sympathy for the attempt to reconstruct quantum theory, it's just that I don't understand why literally all the quantum foundations guys hang themselves up on the measurement process in quantum mechanics. For what I'm concerned, quantum field theory is the thing, and I'm still waiting for somebody to reconstruct the non-commutativity of annihilation and creation operators.

Finally, let me mention Kevin Kelley's talk "How does simplicity help science find true laws?" Kelley is a philosopher from Carnegie Mellon, and in his talk he explored whether it is possible to put Ockham's Razor on a rational basis. Unfortunately, while the theme could in principle have been very interesting, his talk is not particularly accessible. He assumed way too much knowledge from the audience. At least I get very easily frustrated when technical terms are dropped and procedures are mentioned without being explained, since it's not a field I work in. In any case, I'll spare you the time watching the full thing and just mention an interesting remark that came up in the discussion. Apparently there have been efforts to create a computer software that could simulate a "scientist," in this case for the example of trying to extract a theory from data of the motion of the planets. At least so far, such attempts failed (if anybody knows a reference, it would be highly appreciated.) So it seems, for the time being, scientists will not be replaced by computers.

At the end of the last day we had a discussion session, moderated by Steven Weinstein, wrapping up some of the topics that came up the previous days and some others. One of them is the question about the power of mathematics and if there are limits to what humans can grasp (a theme we have previously discussed here). For a fun anecdote making the point well, watch Steven at 1:13:50 min ("I remember distinctively being in a graduate quantum mechanics class by Bob Wald...") Of course Tegmark's mathematical universe made an appearance as well, another topic we have previously discussed on this blog. For what I am concerned, declaring that all is mathematics may be some sort of unification of the laws of Nature, alright, but it's eventually a completely useless unification. And that brings me to...

Thoughts (mine)

On several occasions at the workshop, I felt like the stereotypical physicist among philosophers, and it took me a while to figure out what I found lacking at this workshop. You could say I'm a very pragmatic person. There's even an ism that belongs to that! If you talk about reality and truth, I don't know what you mean, and I actually don't care. This is just words. I'll start caring if you tell me what it's good for. If you want to reformulate the laws of physics, fine, go ahead. But if you want me to spend time on it, you'll have to tell me what the advantage is. If there's two theories and they make the same predictions, that doesn't cause me headaches. For what I'm concerned, if they make the same predictions, they're the same theory.

What matters in the end about a law or a theory or a model is not whether it's philosophically appealing and not even if there's a rational process by which it's been selected (and btw, what means "rational" anyway), but simply whether it's useful. And usefulness is eventually a notion deeply connected to human societies and values. For that reason I think to understand the scientific method and its success one inevitably needs to take into account the dynamics of the communities and the embedding of scientific knowledge into our societies. (It should be clear that with usefulness I don't necessarily mean technical applications as I have recently expressed in this post.)

Leaving aside that I found this aspect entirely missing to the discussions about the process of science itself and its possible limitations, the workshop has given me a lot to think about. Having said that the pragmatist in me searches for the use in all that enters my ears, I nevertheless have enough fantasy to imagine that some of the themes discussed at the workshop will become central to shaping our thinking about the laws of Nature in the future and thus eventually prove their usefulness. It was a very stimulating meeting and the approaches that were presented are all as bold as courageous. It will be interesting to follow the progress of these thoughts.

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*I once made an attempt to read one of Unger's books, What should the left propose? I had to look up every second word in a dictionary, and even that didn't always help. When I had, after an hour or so, roughly deciphered the meaning of a page it seemed to me one could have said the same in one simple sentence, avoiding 3 or more syllable words. I gave up on page 20. Sorry for being so incredibly unintellectual, but to me language is first and foremost a means of communication. If you want to be heard, you better use a code that the receiver can decipher. Friedrich Engels, for example, was an excellent writer...

Update on the ESQG 2010

As previously mentioned, I am presently organizing a workshop on Experimental Search for Quantum Gravity (ESQG 2010) that will take place here at NORDITA in beautifully, endlessly sunny Stockholm, July 12-16. The workshop website is here. We meanwhile have almost all abstracts and, together with my co-organizers Greg Landsberg and Lee Smolin, I managed to assemble a preliminary program.

The phenomenology of quantum gravity is a very interdisciplinary field of research that combines many different areas of physics, from particle physics (high energy and high precision) over astrophysics to cosmology, both the theoretical and the experimental side. This diversity is reflected in our participants in the talks we will have. We'll further have several discussions at the meeting to stimulate the exchange and also to identify the key questions that are on people's minds. The topics of the discussion sessions will be:

• What to sacrifice?
  Moderated by Claus Lämmerzahl, this discussion is meant to explore the question which principles of our today's theories may be violated by quantum gravity, what reasons there are to expect this, and how we can go about to test it. Claus has been participating also in the first installation of ESQG, which took place at Perimeter Institute in 2007. He is well known for his work on the phenomenology of quantum gravity, most notably Lorentz invariance violation and modified dispersion relations.


• The Future of Particle Physics.
  Moderated by Greg Landsberg, the title is self-descriptive. Greg Landsberg is very well known in the hep community for his work on physics beyond the standard model, in particular the possibility of observing black holes at the LHC.


• Experiments and Thought Experiments
  Moderated by Amit Hagar (who I got to know through one of his papers on which I commented here, and who is currently working on a book on the history and philosophy of the minimal length), this discussion is meant to explore the value and limits of thought experiments. (We have had a related discussion here.)
  

Related: I learned the other day that there will be a workshop in Paris, starting tomorrow, on Fundamental Physics Laws: Gravity, Lorentz Symmetry and Quantum Gravity. The Paris workshop touches on some of the topics that will also be discussed at our workshop.