Thursday, December 07, 2006

Have a Stringy Christmas

What's new? Joe Polchinski's review 'All Strung Out?' of Peter Woit's and Lee Smolin's books over at CV (via Asymptotia). The choice of the title is quite ironic. I wonder if he knew this had almost been the title of Lee's book (without the question mark, I presume). The review is worth reading, whether you like or didn't like the books and/or authors.

Besides this new round in the discussion (I predict of order 200 comments over at CV), look what I found in my inbox: Stringy Christmas greetings from last December :-)

----- Original Message -----
From: "D****** M*******"
To: "KITP Lunch List"
Sent: Thursday, December 08, 2005 4:05 PM
Subject: [strings05] song lyrics

Here are the lyrics:

[...]

Song #2: The Maldacena, by Jeff Harvey (1998)

You start with the brane
and the brane is BPS.
Then you go near the brane
and the space is AdS.
Who knows what it means
I don't, I confess.
Ehhh! Maldacena!

Super Yang-Mills
with very large N.
Gravity on a sphere
flux without end.
Who says they're the same
holographic he contends.
Ehhh! Maldacena!

Black holes used to be
a great mystery.
Now we use D-brane
to compute D-entropy.
And when D-brane is hot
D-free energy.
Ehhh! Maldacena!

M-theory is finished
Juan has great repute.
The black hole we have mastered
QCD we can compute.
Too bad the glueball spectrum
is still in some dispute.
Ehhh! Maldacena!


#############################################################
This message is sent to you because you are subscribed to
the mailing list strings05@kitp.ucsb.edu.


----- End of Original Message -----

Tuesday, December 05, 2006

Nikolaus

December 6th is Nikolaus day in Germany, a tradition that comes very close to the North American Christmas. The evening before Nikolaus, children put a boot in front of the door. If they were good children in the past year, they will find the boot filled with goodies the next morning. Parents shamelessly use the occasion to demand that every single shoe in the household has to be cleaned.


Unlike cheerful Santa Claus however, Nikolaus comes with a dark companion, called Knecht Ruprecht. Knecht Ruprecht doesn't wear red and white, but black and brown, and he carries with him a rod and a sack. If you haven't been a good kid, or didn't convincingly clean your stupid boots, you'll get hit with the rod. If you really messed it up (say, by writing silly comments on other people's blogs), you'll get packed in the sack and carried away to his home in the black forest.

Well, yes, that's not politically correct, but that's how the story goes. Another thing that is probably politically incorrect is how my granny used to tell the story. In her version, the evil Knecht Ruprecht wasn't from the black forest, but was actually black and from Africa. If you want to see what Knecht Ruprecht allegedly looks like, check the Wikipedia entry Companions of Saint Nicholaus. Then have another look at your boots, and reconsider if you really think they are clean enough.

Though the origin of the European Knecht Ruprecht tradition is kind of unclear, Saint Nicholas goes back to a real person. Saint Nicholas lived in the 4th century, when he was bishop of Myra, which is today Demre in the Antalya province of Turkey. Saint Nicholaus had a reputation for secret gift-giving (though I wonder how secret it can have been if he had a reputation for it).

Saint Nicholaus is also the patron saint of sailors.

Have a wonderful Christmas season, and keep your boots clean!

TAGS:

Sunday, December 03, 2006

Book Cover Physics

Books which want to be sold need attractive covers besides cogent content - that's because potential readers who pick up new publications at bookstores by chance are still an important target group for publishers. Even the mechanisms of selling books on the internet are not so different yet.

For books on scientific topics, it has always been quite common to use artwork on the cover that is both aesthetic and appealing and related to current trends in science, thus, to use illustrations that are, in a sense, icons of the scientific development of their time. Bee's recent post about Bacon reminded me of a wonderful example of an (in my eyes) extremely attractive book illustration which demonstrates this point: It is the frontispiece of the Instauratio Magna, the major work of Francis Bacon containing the Novum Organum, where he explains his new method for scientific investigation.



It's not a cover illustration as we know it today, since back in 1620, when it was published, books were just bound in heavy leather, and there were no book jackets. But the ships that come in from the wide, open sea of unexplored knowledge, and bring with them funny plants and animals from remote and newly discovered parts of the world are a beautiful metaphor for Bacon's' ideas at a time when British mariners started to rule the waves.

Modern tools of exploration are not any more large ships, but instead test tubes, microscopes, telescopes, space probes, and particle accelerators. And indeed, spectacular photos by the Hubble Space Telescope feature on the covers of many books on astronomy, cosmology, or even string theory. However, with the huge amount of amazing Hubble pictures, the one icon picture is missing - a role maybe best taken over by the COBE, then WMAP maps of the cosmic microwave background, as far as astrophysics and cosmology are concerned.

Here, following a severe personal bias, I want to talk a bit about two beautiful illustrations coming from particle physics - one quite old by now, but still often in use, the other more recent, and, I guess, with a huge potential for use in the near future ;-)







The first illustration shows a chaos of curved, fancy blue lines against an amber background. It comes with several degrees of changes applied to the original, and it was used recently on the covers of the Jonathan Cape edition of Not even wrong and The Scientist as Rebel by Freeman Dyson, New York Review Books (2006). The photo also features on The Particle Garden: Our Universe As Understood by Particle Physicists by Gordon Kane (Helix Books, Addison Wesley Publishing Company, Paperback, July 1996), Understanding the Universe: From Quarks to the Cosmos by Don Lincoln, (World Scientific Publishing Company, October 2004, Paperback), and the now out-of-print 1994 Canto edition of Quantum Physics: Illusion or Reality? by Alastair Rae - that's where I had seen it for the first time, as far as I remember.

There may be many more book covers where it has been used, perhaps someone knows of some other titles.

The origin of the illustration has been discussed before on Peters blog, and Peter refers to the interactions.org database.

But the original photo is from CERN, and can be found with more information and links at the CERN Document Server, cdsweb.cern.ch/record/39312. Included there is also a short list of some publications where it has been used.


cdsweb.cern.ch/record/39312


As for the content, the photo shows, according to the CERN record, an artistically enhanced picture of particle tracks in the BEBC, Big European Bubble Chamber. Bubble chambers were the devices of choice for the detection of the tracks of charged particles created in all kinds of nuclear and elementary particle collisions in the 1960s and 1970s. Filled with a liquid that can be brought in an overheated state, charges particles which cross the liquid serve as the seeds where boiling set in, and thus, tracks are marked by traces of small bubbles of boiling liquid.

More background on the CERN image can be found in the August 2004 issue of the CERN Courier, with the figure caption Picture postcard: Famous postcard view of a neutrino interaction in BEBC (the Big European Bubble Chamber) filled with a neon-hydrogen mixture. Indeed, the picture was sold as a postcard at CERN when I was there for the first time in 1999 - I had sent this postcard to several friends then!

Concerning the science behind the picture, it seems that the BEBC was used mainly for neutrino experiments - the December 1998 issue of CERN courier has more about that, www.nu.to.infn.it/exp/all/bebc links some papers related to BEBC experiments, and just citing from CERN Bulletin 20/2004, which shows this photo of the installation of the BEBC:



cdsweb.cern.ch/record/41546: The vessel of the Big European Bubble Chamber, BEBC, was installed at the beginning of the 1970s. The large stainless-steel vessel, measuring 3.7 meters in diameter and 4 metres in height, was filled with 35 cubic metres of liquid (hydrogen, deuterium or a neon-hydrogen mixture), whose sensitivity was regulated by means of a huge piston weighing 2 tonnes. During each expansion, the trajectories of the charged particles were marked by a trail of bubbles, where liquid reached boiling point as they passed through it. The first images were recorded in 1973 when BEBC, equipped with the largest superconducting magnet in service at the time, first received beam from the PS. In 1977, the bubble chamber was exposed to neutrino and hadron beams at higher energies of up to 450 GeV after the SPS came into operation. By the end of its active life in 1984, BEBC had delivered a total of 6.3 million photographs to 22 experiments devoted to neutrino or hadron physics. Around 600 scientists from some fifty laboratories throughout the world had taken part in analysing the 3000 km of film it had produced.

The BEBC is now on display on a lawn near the CERN cafeteria, where it looks like some alien spaceship ;-)...



cdsweb.cern.ch/record/41091: Group of belgian physics teachers in front of BEBC bubble chamber, in March 2000

Bubble chambers, like emulsion film techniques or similar methods to record tracks of particles, have one big disadvantage: events are fixed on film, and to do a physics analysis, thousands of photos have to be checked "by hand". This is a very tedious job, which often was done by women "scanners".



LBNL Image Database 96602983: Operator, Barbara Srulovitz, maps particle tracks with Alvarez Scanning and Measuring Projector.

In a sense, the huge BEBC was a kind of dinosaur, the end point and culmination of this type of detection device. For an automized analysis using electronic computers, it would have been nice to have complete information on all particle tracks available in some electronic form. That's what can be achieved with wire chambers, or, a widely used variety of these kinds of detectors, time projection chambers (TPCs).

A time projection chamber is a large chamber filled with gas. High-energy charged particles emerging from a collision event will ionize this gas along their paths, leaving behind tracks of electrically charged gas molecules. The whole TPC is subject to a homogenous electric field, which moves the pattern of tracks drawn in electrically charged gas molecules towards small-meshed grids of wires. There, the ionized gas molecules create electrical signals, and from the location of the wires which are triggered and the time delay between the collision and the detection at the wire (which is the time the ionized gas molecules need to drift from the position of the track to the detector wire), it is possible to reconstruct the complete three-dimensional pattern of all tracks of charged particles emerging from the original collision. TPCs are now in use since more than 25 years and are a central component of many particle physics experiments. I am not an experimentalist, so I have no inside view of all the complexities and difficulties which are part of this data gathering process. But I am amazed that it is possible to reconstruct particle tracks with a spatial resolution below one millimeter, using state-of-the art TPCs!

In collider experiments, such as at RHIC, TPCs are large cylindrical chambers, with the central axis of the cylinder coinciding with the beam axis and the collision point at the centre of the chamber. A TPC is the main detecting device of the STAR experiment, the Solenoidal Tracker at RHIC. This photo, which is part of a series of photos provided by the Lawrence Berkeley National Lab, shows the TPC of STAR.



It was with data from the TPC of STAR that this graphical representation of one of the first gold-gold collisions at RHIC was created in June 2000.



The graphics shows the projection of the tracks of electrically charged particles emerging from the gold-gold collision. There are in the order of 3000 charged particles emerging from central collisions, and the radial motion of these particles is displayed in the figure.

The analysis of the radial motion of all the particles produced in a heavy-ion collision provides such observables as the elliptic flow, which describes the deviation of the pattern of motion from perfect radial symmetry for non-central collisions, and which allows to estimate the viscosity of the hot and dense nuclear matter created in the collision.

But this is a second step of the analysis: First, the tracks, and momenta, of as many particles as possible have to be determined. These tracks make up the wonderful picture from STAR, with its striking resemblance to the iris of an human eye. It shows a central part of the science of heavy-ion physics in an eye-catching way, and features in many talks and articles about heavy-ion physics. This STAR picture has become kind of an icon of heavy-ion physics.








Which brings me back to my initial topic of the book covers: The RHIC "iris" of the STAR-TPC has made it, as far I could see, on the covers of The QCD Vacuum, Hadrons and Superdense Matter by Edward V. Shuryak, (World Scientific, 2nd edition, 2004), Alpha and Omega: The Search for the Beginning and End of the Universe by Charles Seife (Viking, 2003), and Quark Gluon Plasma 3 edited by Rudolph C. Hwa, and comment writer X. N. Wang (World Scientific, 2004)

But considering the dark and mysterious appeal of this photo, my guess is that we will see it more often on book covers of future, new releases.

TAGS: , , ,

Low Food Security

The lucky citizens in the land of plenty will never again have to endure hunger. The US Department of Agriculture has replaced the condition of 'hunger' with that of 'very low food security'. Though I'd agree with Mark Nord, the lead author of the report, that 'hunger' is not a scientifically accurate term, I find the chosen alternative not so much better. I'd have said the majority of people in the so-called western civilization lives in a state of constant very low food security: one is never quite sure what it is one actually eats. Shockingly, the report finds: "[...] that 12 percent of Americans — 35 million people — could not put food on the table at least part of last year. Eleven million of them reported going hungry at times."

See also:

Political Gateway: USDA eliminates 'hunger' from reports
Seattle Times: U.S. agency changes "hunger" to "very low food security"
SF Chronicle: My stomach is touching my back


TAGS:

Wednesday, November 29, 2006

This and That

Christmas is coming closer, daylight is getting less and less, but except for one day in October we still haven't seen snow here in Waterloo. For once it seems I'm on the better side of climate change. What's interesting today:
  • My ficus died. Please send condolence cards directly to the Composting Council of Canada.

  • Wired has an article about the LHC: Subatomic Inferno Under the Alps

  • The December Issue of Phyiscs Today has reviews of Peter Woit's and Lee Smolin's books. The reviews aren't exactly nice, but kind of interesting and different from other reviews I've read so far. The author, Kannan Jagannathan, roughly says all this talk about the so-called-crisis is on weak feet, and The End of Physics is nowhere near by. He ends with the sentence 'Smolin and Woit appear to think that it is time to cut the short-term benefit of the doubt for string theory, but many other physicists might be willing to let a little more time pass before rendering judgement.' I agree on most of the criticisms Jagannathan raises, but I think that he's shaking off the raised concerns in both books too easily.

  • If you still have doubts that Waterloo, Ontario is the place-to-be, let me mention that the construction area on King Street has eventually turned into the Waterloo Town Square. This doesn't only mean that PI has now a Starbucks withing 3 minutes walk (or a 10 minutes drive respectively, because you don't get out of the parking lot), but also the largest LCBO in Southwestern Ontario (that LCBO being the place where you're supposed to buy liquor).

    "TORONTO, Oct. 24 /CNW/ - With popping corks and toasts with Ontario sparkling wine, the LCBO today officially opened its new Waterloo Town Square store at 115 King Street North in Waterloo. The new 16,633 square foot store is the largest LCBO outlet in Southwestern Ontario [...]" >>read more

    For some photos, see here.

  • The German magazine 'Der Spiegel' has an article titled 'Weltall aus Musik' (Universe made of music). Which briefly mentions Lee Smolin's and Peter Woit's books, but mostly makes fun out of the string theory landscape. That fun being on an elementary school level of the form:

    "In a faraway Cosmos, there live intelligent Dampfnudeln [a bakery]. They can travel almost as fast as light. For this they use the recoil of improved pressure cookers. [...]"

    The article cites Wolfgang Lerche saying "A deep gap is dividing particle physics. String theory is forced onto the defensive.". Besides this, the article hardly contains any interesting information.

  • Last week, V. Mukhanov gave a very nice colloquium about inflation which is now online:

    Inflation after WMAP (Windows Media , Macromedia Flash , MP3 Audio , PDF)
    Speaker(s): V Mukhanov
    Date: 23/11/2006 - 11:00 am

    If you are looking for an easy to follow introduction, I can recommend the talk. It is also quite entertaining.

  • If you want to see a cosmologist getting upset about inflation, look at this video.

  • Yesterday I stumbled across this interesting paper:

    Quantitative Analysis of the Publishing Landscape in High-Energy Physics
    Authors: Salvatore Mele, David Dallman, Jens Vigen, Joanne Yeomans

    Abstract: World-wide collaboration in high-energy physics (HEP) is a tradition which dates back several decades, with scientific publications mostly coauthored by scientists from different countries. This coauthorship phenomenon makes it difficult to identify precisely the ``share'' of each country in HEP scientific production. One year's worth of HEP scientific articles published in peer-reviewed journals is analysed and their authors are uniquely assigned to countries. This method allows the first correct estimation on a ``pro rata'' basis of the share of HEP scientific publishing among several countries and institutions. The results provide an interesting insight into the geographical collaborative patterns of the HEP community. The HEP publishing landscape is further analysed to provide information on the journals favoured by the HEP community and on the geographical variation of their author bases. These results provide quantitative input to the ongoing debate on the possible transition of HEP publishing to an Open Access model.


  • And finally, if you enjoyed the Rube-Goldberg machine made out of Honda parts, you might also like this video. I think, I finally found a purpose for all my CD's that are catching dust since iPod.


Sunday, November 26, 2006

The Beauty of it All

I can't say I was drawn to theoretical physics because I found it utterly beautiful. Indeed, I found physics in middle school extremely confusing and ugly. We were essentially presented a set of equations, and asked to measure or compute things without any apparent reason. I definitely preferred mathematics, where things seemed to have a relation to each other, and were build up on well defined and reliable axioms.

I was lucky though that I had a very patient teacher who tried to explain me that all these equations actually can be derived from common principles, just that the maths necessary for this was missing in 8th grade. (E.g. the factor 1/2 in the equation s = 1/2 g t2 suddenly makes sense, when you learn what integration and differentiation is.) I realized only much later that in most of her explanations she was actually talking about differential equations, and the variational principle - what I would call one of the most beautiful concepts in physics.

Some weeks ago I read an article in the October issue of Scientific American Mind "The Neurology of Aesthetics", which investigated the neurological causes of what humans find beautiful. This post is a very free interpretation of the article, and a comparably free relation to beauty in physics, since I don't think it is necessary to have college level maths skills to see the beauty of it all.




Symmetry/Broken Symmetry


The SciAm article states that allegedly we are attracted to symmetry because it is a property of 'most biological objects' and 'it pays to have an early warning system to draw your attention to symmetry [...] This attraction explains symmetries allure [...]'. Which I can't really agree on, because symmetry apparently is a feature also of non living objects, whereas there exist 'biological' objects that are a) not symmetrical but worth paying attention (don't worry if you can't read the text, I'm still feeling slightly sick), or b) symmetrical but doubtful in their aesthetic value (don't click if you suffer from arachnophobia). But whatever the neurological reason, symmetry is mostly considered as beautiful, which is also the case in physics:

There are the obvious examples of crystal growth (see here for more snowflakes) which are based on lattices. Then there is the power of symmetries to classify a confusing amount of particles: the quark model, a brilliant example of how symmetries (in this case SU(3)) allow to explain the observed particle zoo by building them up of only some few constituents. (See here for more info about the Eightfold Way).


The pictures below show probability distributions of electrons in the hydrogen atom, as one can compute with elementary quantum mechanics (pictures drawn with this applet, if you want to play around).


The principle of symmetries finds its most powerful application in gauge symmetries, which are the foundation of the standard model of particle physics.

However, as my mother likes to say 'Symmetrie ist die Kunst der Blöden.' -- 'Symmetry is the art of the poor.' Which is true in the sense that perfect symmetry is just boring. From the photos at the beginning of this section, none has perfect symmetry. The breaking of symmetries is essential to the formation of life. It is what makes nature an interesting place.



Patterns and Structures


The left picture above shows a piece of the Cosmic Microwave Background, the results from the WMAP measurements. From the sizes and colors (temperature fluctuation) of this pattern one can extract information about the structures at the time of radiation-matter equality.

Another example for structures in physics is closely connected to the search for a theory of quantum gravity. It is generally expected that at smallest scales (close by the Planck length) the spacetime we sit in is not a smooth background but quite messy and quantum foamy, see e.g. here for a picture and a brief introduction.



Less is More



Simplification is one of the primary goals in theoretical physics. Basically the whole search for a theory of everything can be thought of as a search for simplification. Some of the most compelling examples for a successful simplification are maybe the unification of (classical) electric and magnetic phenomena in Maxwell's equations, and the quantum field theory of electro-weak interactions.

But simplification is not only a goal. It is also an useful tool. Think about describing the properties of vapor. You don't compute the motions of every single atom, instead you describe the whole system by some few properties like temperature, pressure and volume.

Another well known example is considering the cow to be a sphere. This might be quite a crude approximation of you think about said cow as your next dinner. But If you want to describe, say, how a cow drops out of a plane and hit some innocent fisherman, it's completely appropriate to describe it as a sphere.

Simplification is also behind the cosmological principle, according to which the universe is roughly the same everywhere, and looks the same in every direction. This sounds pretty silly if you look at the screen in front of you, but makes sense if you think of galaxies as particles in a cosmic fluid. The CMB structures shown above are departures from this over-simplified description.

Besides being beautiful, simplification is an extremely powerful concept that can save a lot of brain time.


Amplification




The SciAm article refers to this as 'hypernormal stimuli': an amplified reaction to unusual modifications of a certain property, like high contrast colors, exaggerated shapes etc. They write 'We do not know why this effect occurs but it probably results from the way in which visual neurons encode sensory information' (Which imho is equivalent to saying they don't know anything.)

To come to theoretical physics, it seems that humans are just fascinated by strange thought experiments like: What would happen if you could travel at, or even faster than the speed of light? If you fell into a black hole? If the electron mass was only a bit larger? If space-time was made of braids? What if you'd try to microwave a marshmallow? Describe everything as tiny vibrating strings? What if you could fly? Travel back in time?

There's no doubt physicists like extremes.


Problem Solving

I was kind of surprised to see the SciAm article listing problem solving as a factor for beauty, the reason being 'When the correct fragments click into place, we feel a gratifying 'aha'.' This doesn't only make us like the picture whose 'problem we solved', but it is essentially what physics is all about: explaining the underlying concepts of things that look puzzling at first sight.


Another nice example for the fascination caused by problems are maybe also Esher's impossible pictures.


An additional point that doesn't relate to beauty in theoretical physics is that of a visual metaphor which draws its relevance from the historical and sociological context.


And if you want to get a perspective of how our concept of beauty is affected through the media, look at this video.



    Don’t the hours grow shorter as the days go by
    We never get to stop and open our eyes
    One minute you’re waiting for the sky to fall
    The next you’re dazzled by the beauty of it all



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Saturday, November 25, 2006

Isn't it nice...

... when things just work?

Look at this totally amazing Rube-Goldberg machine in a Honda ad:



"This Advertisement for the new Honda Accord was shot in real time with no CGI involved in the sequence. It required 606 takes and cost $6 million to shoot and took 3 months to complete.

The equipment was so precisely set up that the crew literally had to tip toe around the set for fear of disturbing things, which led to some unexpected problems. "As the day went on, the studio would get hotter," says Steiner. "It meant that the wood would expand and the cog or exhaust that spins around would move slightly faster." These tiny changes made big differences to the precision set-up of the equipment......

.....The sequence where the tires roll up a slope looks particularly impressive but is very simple. Steiner says that there is a weight in each tire and when the tire is knocked, the weight is displaced and in an attempt to rebalance itself, the tire rolls up the slope."
source: steelcitysfinest.com

Thursday, November 23, 2006

More on AdS/CFT and RHIC

Last week, Pavel Kovtun gave a seminar here on PI about the AdS/CFT correspondence and its applications for RHIC physics. For a brief introduction, see e.g. our earlier post Does String Theory explain Heavy Ion Physics?. It was the same seminar that I heard at the KITP in spring, and on which I reported in the Banana-post. If you are interested in the topic, you can now download audio, video and slides from the PI streaming seminars:

On Tuesday, I missed another seminar on the subject, but as the seminar schedule tells me, on Thursday there will be even another seminar by Andrei Starinets.

It's not that I am so tremendously interested in the topic, I just find it remarkable how much fuss there is around it. Despite the fact that Pavel started his talk with a very nice motivation about RHIC experiments, I could not avoid noticing the sharp contrast between his predictions, and the predictions I am used to from nuclear physics talks. The latter of which usually include some plots of calculated observables, how well they fit the actual data points (and error bars to both if necessary). Based on this, a conclusion on the quality of the model should be given, and how they compare to other approaches. It seems to me that the AdS/CFT calculations haven't yet quite reached this state.

I have wondered for some while how the importance of the results is seen from the nuclear physicist's community, which has gathered last week in Shanghai on the Quark Matter 2006. The Quark Matter is the largest annual meeting of the community, which I am very sorry to have missed this year. But interestingly, yesterday a friend (who kindly agreed that I post his email) reported the following on the closing talk:

----- Original Message -----
From: "******* *******"
To: [...] sabine[@]perimeterinstitute.ca
Sent: Tuesday, November 21, 2006 9:00 PM
Subject: Tearing string theory a new a*hole


This is pretty weird/interesting.
We just concluded quark matter. At the theory summary, in what was supposed to be the closing session, the guy speaking (Larry McLerran, a pretty famous person) went on a 20 minute rant on string theory in general, attempts to use it to describe RHIC in particular, and Brian Greene in personal.


See
Larry McLerran's talk (PPT), slides 19 onwards for what I am talking about (the slides do not convey his tone, e.g. giving Brian Greene a "Pinocchio award").

[...]

In any case, an amusing closing talk to conclude a somewhat politicized (no surprise) but fun (as always) conference.


[...]


------End of Original Message ---------


The powerpoint file is pretty large (11MB), so here are the last some slides as jpgs (click to enlarge), starting with the Pinocchio award for Brian Greene:











Please don't ask me details about the talk, as I mentioned, I didn't hear it. This is just to convey some skepticism from 'the other side'.

Update: See also Clifford's post Nuclear Guy goes Nuclear at Asymptotia, and Lubos' post Heavy Ion Physics and AdS/QCD.

Update: A written version of the summary talk is now available on the arxiv

Theory Summary: Quark Matter 2006
Authors: Larry McLerran
hep-ph/0702004

Wednesday, November 22, 2006

A Higher Dimensional Poem

These days, when I look out of my window and see the hazy shades of winter, I miss Santa Barbara! Especially so, because they used to distribute so pretty poems on their email list. Here is one I like best:

----- Original Message -----
From: "J****** T******"
To: "KITP Lunch List"
Sent: Wednesday, March 08, 2006 9:03 PM
Subject: [highdgr06] a poem

Welcome to the Gravity Party!

Once before
We thought there were 4
now instead
there may be 10

So drop the dread,
while 4 is NICE,
8 is TWICE,
And while 10 is good,
let it be understood,
Should we go by the letter,
or is 11 Better?

Then Why stop there?
should you care,
Let's add to the mix,
D= 666!

#############################################################
This message is sent to you because you are subscribed to
the mailing list highdgr06@kitp.ucsb.edu.

----- End of Original Message -----

Saturday, November 18, 2006

Did you know... (II)


... that the Baconian method is suitable also for vegetarians?


Sir Francis Bacon, born 1561 in London, began his professional life as a lawyer, but became best known for his early investigations about the method of science, called the Baconian method. In case you had never heard from that guy before, here is what you definitely know:

It was Bacon was is who concluded


Scientia potentia est.
(Knowledge is Power.)


~Francis Bacon, Meditationes Sacrae, 1597

The Baconian method essentially suggests you clear up your mind from all prejudices before you try to do science (Idols of The Mind: Tribe, Cave, Marketplace, Theater), and then approach the issue constructively (pars construens) in three steps:

  1. The table of presence ("tabula praesentiae") lists all the cases wherein the phenomenon exists whose formal cause is sought [...]
  2. The table of absence ("tabula absentiae") lists all the cases in which the phenomenon under analysis does not appear to be present [...]
  3. The table of degrees ("tabula graduum") lists the increase and decrease of the given phenomenon in one object or in different objects.

This third table [...], should bring us to know the formal cause (law) of the phenomenon itself. It is not always easy to arrive at a formulation of the law [...]. In such a case we must be content with a temporary or working hypothesis, and await new instances, new experiments."


The recent results from high redshift supernovae, and the implications for our knowledge about the nature of dark energy (constraints on the equation of state), are a nice example for 'new instances' that can be included in the 'tables'. Hopefully, the new data will eventually allow us to extend our current 'working hypothesis'. So far, dark energy still is essentially a parametrization for some mysterious component of our universe whose origin we don't understand - but a parametrization which works annoyingly well! For more info about the new supernovae data, see Sean's post at CV or Clifford's post at Asymptotia.

But back to Sir Francis: early in the year 1626, he applied his method of scientific research to investigate the possibility of using snow to preserve meat. While stuffing the chicken with snow, he contracted a fatal case of pneumonia, and died on April, 9th 1626.


See also: Wikipedia on the Baconian method



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Hazy Shade of Winter

Yes, it's this time of the year again. Deadlines are approaching. And I'm enormously happy that this January I will not be sorting through letters saying 'Thank you for your interest in our theory group... We regret to inform you...'


If you are out on the market for position hunting, this post is especially for you: Good luck, don't give up!



    "Time, time, time,
    See whats become of me
    While I looked around
    For my possibilities
    I was so hard to please

    But look around,
    leaves are brown
    And the sky
    Is a hazy shade of winter

    [...]

    Hang on to your hopes, my friend
    That's an easy thing to say,
    But if your hopes should pass away
    Simply pretend
    That you can build them again"





    TAGS: ,

    Wednesday, November 15, 2006

    Did you know...

    ... where the name Google comes from?

    Google is a play on the word googol. A googol is the number

    10100 ,

    which is a one followed by 100 zeros. It looks like this:

    10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
    000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

    The name 'googol' was invented by nine-year-old Milton Sirotta, the nephew of the American mathematician Edward Kasner, back in 1920.

    The word was slightly scrambled, and used to name Google, to indicate the incredible high amount of information available on the web.

    If you want to get an impression of how large a googol is, see what Schroeder had to say about that:

    But somewhere out there in the vast possibilities of the landscape, there are even universes in which Lucy got lucky...




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    NASA announces Discovery of Dark Energy...



    NASA Schedules Dark Energy Discovery Media Teleconference

    NASA will host a media teleconference with Hubble Space Telescope astronomers at 1 p.m. EST Thursday, Nov. 16, to announce the discovery that dark energy has been an ever-present constituent of space for most of the universe's history.

    Reporters must call Ray Villard at the Space Telescope Science Institute Press Office, Baltimore, at: 410-338-4514 (villard@stsci.edu) or Cheryl Gundy at 410-338-4707 (gundy@stsci.edu) for participation information. Images and graphics about the research will be posted shortly before the start of the briefing at:

    Briefing participants:
    -- Adam Riess, astrophysicist, Space Telescope Science Institute and Johns Hopkins University, Baltimore
    -- Mario Livio, senior astrophysicist, Space Telescope Science Institute
    -- Louis-Gregory Strolger, astronomer, Western Kentucky University, Bowling Green, Ky.
    -- Sean Carroll, senior research associate, California Institute of Technology, Pasadena, Calif.

    Audio of the event will be available on the Internet at:


    For NASA TV streaming video, schedule and downlink information, visit:

    Tuesday, November 14, 2006

    PS on Dark Matter

    Two weeks ago, I reported on Stefan Hofmann's work about the influence of dark matter on the small scale structure of our universe. Last week, his collaborator Anne Green from the University of Nottingham gave a very good follow-up seminar on their work, and thanks to the new PI-websites, I can actually give you a link:

      Dark matter: from the early Universe to the Milky Way
      Speaker: Anne Green
      Date: 11/07/2006, 2:00 PM CST
      Length: 1 Hours, 5 Minutes, 46 Seconds
      Abstract: The initial conditions for structure formation, and hence the dark matter distribution on sub-galactic scales, depend on the microphysics of the dark matter in the early Universe. I will focus on WIMPs and explain how collisional damping and free-streaming erase perturbations on comoving scales k> ~1/pc. Consequently the first structures to form in the Universe are mini-halos with mass of order the Earth. I will then describe the status of calculations of the subsequent dynamical evolution of these mini-halos. Finally, if time permits, I'll briefly overview the microphysics of axions.


    If you have the time and an interest in dark matter, you should invest the hour to look at it! During her talk, I noticed that in my earlier post I forgot to point out the important thing to notice in the figure below: the absence of even smaller structures in the magnification.


    (picture from astro-ph/0501589)



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    Monday, November 13, 2006

    Smoke came out of our theories...

    Today I stumbled across the Honeywell Nobel Interactive Studio:

    "[...] The Honeywell - Nobel Laureate Lecture Series [is] the centerpiece of a global education initiative designed to connect students across the globe with Nobel Prize winners in Chemistry and Physics. [...] A multi-year effort, the Honeywell – Nobel Initiative combines on-campus events, interactive webcontent and broadcast programming to link one generation of leading scientists with the development of the next."

    Since I found out via NEW that these websites were only fairly recently launched, I want to encourage you to have a look at it. They have some very nice videos there. E.g. here is Leon Lederman, Nobel-Laureate in 1988, about the search for the Higgs:




    (click on the picture or here, I'm having some problems embedding the flash)


    "[...] and so far, no one has come up with a good alternative. But I suspect, there are some kids in junior high school [...] who will have within their minds the seeds of discovery... "




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    Saturday, November 11, 2006

    Hypocritical



      hypocritical - professing feelings or virtues one does not have



    Having been taught by Bert Schroer about the importance of irony and sarcasm in particle physics, I'd like to try an application of my newly won insights: Here is a rare case of an opportunity to learn from a world leader: George W. Bush and The Power of Words:


    What I learn from this is that we should be wise and stop talking about whether or not we are looking for a 'Theory of Everything' by scanning over a whole landscape. Instead, we should bridge the increasing gaps in our community and rename our combined efforts into:

    Theory of Everything Related Program Activities

    God bless America.

    PS: Nov 11th, at 11:11 am is the official begin of the Carnival Season in Germany.



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    Thursday, November 09, 2006

    Lisa Randall on Discover

    Today at 2pm the live-chat at discover.com with Prof. Lisa Randall from Harvard took place. It was a very balanced text interview in which Randall answered questions from the audience that were picked by the moderator (Amos Kenigsberg). He did a good job, it was interesting, and a lot of stuff was covered. As always, Lisa Randall was good in communicating her work.

    Here are some of the more interesting questions (I wasn't able to copy and paste from the Java applet, so you'll have to endure screenshots). The person with name 'famous' is the moderator.

    The first question was from someone called 'Xman':



    In the answer I think Lisa Randall was referring to this paper on which I have commented in my post Why do we live in 3+1 dimensions.

    As one would expect, there was a question about the LHC, and also one about the so-called string theory backlash:



    She was also asked by 'qd_survivor' to comment on science blogging:



    Anybody an idea what that guy was surviving? Here is my question, which I think she misunderstood:



    (I don't know where these brackets come from, seems to be a software bug).
    The question was whether string/loops/spin networks/other funny things out there can eventually turn out to be part of the same fundamental theory. And if mathematical consistency alone makes the fundamental theory unique. I agree on her answer, but it wasn't the answer to my question.

    Besides this, I learned that the German version of her book 'Warped Passages' was just published. It seems to be one of the rare cases in which the German title 'Verborgene Universen' (hidden universes) makes sense, and imo is actually better than the English one.

    A funny side remark: some time ago I piped a German research proposal through babelfish, which attempted as well to translate my reference list from German to English. The name Randall got 'translated' into Edge of the Universe. (Which is correct: the German word Rand means edge, and All is an expression for Universe.)

    Update: Thanks to Georg, I found out that 'qd_survivor' has a post 'Two answers from Lisa Randall' on the blog A Quantum Diaries Survivor, where you also find a complete transcript of the chat.


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    Wednesday, November 08, 2006

    This and That

    • The 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2006) will be held in Shanghai, China on November 14-20, 2006. For more information, see their website.
    • Christine Dantas has deleted most of her blog 'Background Independence'. It makes me very sad to see her go. For explanations, see 'Dantas is missing' at PF, or the comment section at Not Even Wrong. Update: Christine has put up a partial backup of her posts.
    • Lee Smolin has a feature article in the November issue of Physics Today, titled 'Quantum Gravity faces Reality'. If you are registered, you can follow this link. It briefly explains attempts to measure effects of, and approaches to quantum gravity (String Theory, LQG, CDT, Spin Networks).
    • The Perimeter Institute has finally launched the new websites!! They look great, they work better, and it's even possible to find the seminar you're looking for. Great job :-)
    • Tomorrow, Thursday, Nov 9th at 2:00pm EST, there will be an online chat with theoretical physicist Lisa Randall at discover.com . Update: In case you have also wondered how this will work, see the email below.
    • Lee Smolin has written a letter to friends and colleagues, regarding the ongoing discussion about his book. You find the letter on the website The Trouble with Physics.



      ----- Original Message -----
      From: "Amos Kenigsberg" akenigsberg[@]discover.com
      To: "Sabine Hossenfelder" sabine[@]perimeterinstitute.ca
      Sent: Wednesday, November 08, 2006 7:02 PM
      Subject: RE: One last thing

      Dear Dr. Hossenfelder,

      I'm the editor of Discover.com, and I'll be moderating the chat on Thursday. The event is going to be a real-time, online, text-based chat, with Lisa Randall as the guest and people interested in physics -- scientists and non-scientists -- as the audience. The chat will be on theoretical physics, centered around Lisa Randall's take on the field, and it will last for an hour.

      At the beginning of the chat, I'm going to ask a few questions of Prof. Randall, and then we'll take questions from audience members. (I'll select the questions to make sure there's nothing offensive, way off-topic, or really dumb.) Anyone is welcome to comment and ask questions, but we want to keep things civil and generally accessible for lay people interested in science. Arguments with Randall's positions are perfectly welcome.

      As for the technical side, chat readers and participants will need to have Java-enabled browsers. A regular household broadband connection would be great, and I'm not sure, but a dial-up connection might work fine, too. To enter the room, visitors will need to click on the button on this page:

      http://www.discover.com/web-exclusives/lisa-randall-online-chat

      As far as I know, running the JavaScript behind that button is the only way to get into the chat room. [The link will only activate when the chat room opens at around 1:50pm.]


      Please let me know if you need to know anything else, and I hope to see you and your readers at the chat.


      Sincerely,
      Amos Kenigsberg.


      * * * * * * * * * * * * *
      Amos Kenigsberg
      Web Editor
      Discover Magazine

    Tuesday, November 07, 2006

    From a Distance...

    ... the world doesn't always look blue and green... flying over the earth today, I found quite amazing sand formations in Takla-Makan (Desert of Death), China, (click to enlarge).




    If you have Google Earth, you can download my placemark from the first location here, or look it up at Google-maps here. Also interesting: try this placemark, which seems to show some wheel traces in the desert that you can follow for endless miles.

    Special thanks to Andi for the hint.




      From a distance the world looks blue and green,
      and the snow-capped mountains white.
      From a distance the ocean meets the stream,
      and the eagle takes to flight.

      From a distance, there is harmony,
      and it echoes through the land.
      It's the voice of hope, it's the voice of peace,
      it's the voice of every man [...]

      From a distance you look like my friend,
      even though we are at war.
      From a distance I just cannot comprehend
      what all this fighting is for.


      ~ Bette Midler, From A Distance




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