The last couple of weeks have been busy beyond belief, with administrative duties, research, teaching, some travel, and a relative visiting. One of my trips was to Lehigh University, to give a colloquium. Lehigh is the home of Intelligent Design nut job Michael Behe but, since I was visiting the Physics Department, I was able to avoid his nonsense altogether (although the physicists there - wonderful rational people that they are - seem rightly embarrassed to be at the same institution as him).

Yesterday afternoon I drove up to Montreal, to participate in a workshop on The Stabilization of Embedded Defects, at McGill University. This topic (I’ll take a shot at explaining it below) is one in which I have dabbled in the past, but which hasn’t been a part of my research program for some time. However, it is an interesting area and, since the program is being organized by my Ph.D. advisor, Robert Brandenberger (who very recently left Brown to head to McGill), and since good friends like Tanmay Vachaspati and Ana Achucarro (people I haven’t seen in ages) were going to be here, I thought it would make for a delightful trip. So far, I was right!

Embedded defects are an ingenious idea. I’ve discussed the idea of topological defects before, over at Orange Quark, so let me start by repeating that description.

Topological defects are extended solutions to field theories that can arise when the vacuum structure of the field theory is topologically nontrivial. As a somewhat simple example (and, I admit, a clumsy one, but its the best I can do right now), let us model a field theory by standing many pencils on their ends on a table top, and connecting the pencils to their nearest neighbor pencils by springs. What is the vacuum configuration of these pencils? Obviously, because of gravity, each individual pencil would like to lie down on the table, but doesn’t care which direction it is pointing as long as it is lying down. So the vacuum configuration of the theory is all the pencils lying down, facing in the same direction, because if any pencil faces in a direction different from that of its neighbor, then there will be energy bound up in the spring which is stretched between them, which can be reduced by the two pencils aligning. Obviously, there are an infinite number of equivalent vacua, corresponding to all the pencils aligning in any of the possible directions in the plane of the table.

Now suppose that the table is very big (maybe even infinite), and pencils that are very far apart from each other fall down into different vacuum states, because causality doesn’t permit information to travel between them so that they can align. You could imagine, in fact, that pencils that trace out a very large circle all fall down pointing outwards in different directions along that circle. All other pencils inside that circle will try to align with the pencil closest to them, in order to reduce the energy in the springs. However, if you think through this for a moment, you’ll see that there will always be one pencil, the one at the center, which is equally pulled in all directions and so will remain standing up - now stably. In fact, a few pencils on each side of this one will be partially standing up, because of the spring tension.

These few pencils, and particularly the one at the center, represent what is meant by a topological defect. It is a small region of space, in which the field configuration is out of the vacuum manifold, but which remains metastably in that configuration because the topological properties of the vacua chosen by the field at infinity are nontrivial. I won’t harp on about how these topological properties are defined, because it’s more technical than the sketch above and won’t buy us much clarity here.

In the model system above, the topological defect is point-like - it is just a single point in space. In three spatial dimensions one can have either point-like defects (monopoles), line-like defects (strings) or membrane-like defects (domain walls). Which, if any, of these exist depends on the particular particle physics model one considers.

So what are embedded defects? Well, suppose that one takes the above structure, and imposes a new, larger symmetry on the theory, so that the symmetry is large enough that the topological defect can now be smoothly relaxed to the vacuum of the theory. In this case, we have transformed the theory into one with no topological defects, and one might think that nothing of interest remains. However, one is still allowed to write down the original defect configuration, by setting to zero, by hand, the extra fields required to impose the new symmetry. The question is: what happens to this configuration?

It turns out that, for a range of values of the couplings of the theory, although the defect solution is no longer topologically stable, it is dynamically metastable - meaning that once the configuration is there, the field realignments that are required to settle the fields into the ultimate vacuum must go through configurations that are of higher energy than the defect configuration, and so the defect will not decay immediately, as one might have thought from topological considerations alone. Such metastable configurations are embedded defects.

A fascinating fact is that the standard model itself has the requisite vacuum structure for embedded defects - the so-called Z-strings. However, for physical values of the parameters, these configurations are unstable, and so will not form as the universe cools. The purpose of this workshop is to discuss physical mechanisms through which such defects may be again rendered metastable, and thus may contribute to cosmology.

Another goal of the workshop is to understand what kinds of symmetry breaking schemes give rise to such defects - a question that is of pressing importance given the upcoming start of the Large Hadron Collider (LHC) experiments, which may reveal new particle physics structures beyond the electroweak scale.

Today was fun, with some excellent talks and some discussion sessions, one of which - on new cosmological applications - I moderated. Tomorrow there will be more talks, including one by Ana Achucarro on numerical simulations that should cast light on one of the suggested stabilization mechanisms.

The meeting ends on Sunday, after which I’ll head back to Syracuse and hopefully get back to regular blogging.

There are a lot of good science bloggers out there, but overall we are way behind other areas of academia in the realm of scholarly blogging. Social scientists and law professors, in particular — that is, disciplines that regularly interact strongly with the larger social context — seem to have taken to blogging more readily, including at least one Nobel laureate (economist Gary Becker).

Here’s what looks like a major step: a new blog by the faculty of the University of Chicago Law School.

The University of Chicago School of Law has always been a place about ideas. We love talking about them, writing about them, and refining them through open, often lively conversation. This blog is just a natural extension of that tradition. Our hope is to use the blog as a forum in which to exchange nascent ideas with each other and also a wider audience, and to hear feedback about which ideas are compelling and which could use some re-tooling.

The entire faculty! Taking turns blogging, discussing recondite legal issues within an informal format that is readily accessible to interested nonexperts. Jack Balkin has a good take on the project; it will be interesting to see how it develops.

Perhaps, after cautiously observing the experience of their colleagues across campus, more scientists will come to appreciate the fact that they are paid not only to discover new things about the world, but to communicate to others what it is that they’ve discovered.

It’s the 60th anniversary of the Bulletin of the Atomic Scientists, which premiered in December, 1945, just a few months after atomic bombs were dropped on Hiroshima and Nagasaki. The goal of the magazine has always been simple, if somewhat ambitious: to save the world by working to minimize the threat of nuclear war. It came out of a time when physicists were central players in questions of international security.

The most famous product of the Bulletin is of course the Doomsday Clock, an iconic image that is far more famous than the magazine itself. The minute hand on the clock moves in response to the perceived danger of imminent global disaster. It’s fascinating to peek back at the timeline for the evolution of the clock, as it bounces back and forth in response to world events.

• 1947: Seven minutes to midnight. Chosen mostly for artistic reasons, apparently. The original conception didn’t include the idea that the clock would actually move to reflect developments in international security.
• 1949: Three minutes to midnight. The Soviet Union explodes its first atomic bomb.
• 1953: Two minutes to midnight. The US and USSR explode hydrogen bombs.
• 1960: Seven minutes to midnight. International cooperation to check the growth of nuclear weapons grows.
• 1963: Twelve minutes to midnight. The US and USSR sign the Partial Test Ban Treaty, the first international arms-control agreement. (For some reason, the Cuban Missile Crisis doesn’t seem to have really registered — possibly it came and went too quickly.)
• 1968: Seven minutes to midnight. France and China acquire nuclear weapons; arms stockpiles increase while development aid to developing nations languishes.
• 1969: Ten minutes to midnight. The US Senate ratifies the Nuclear Non-Proliferation Treaty.
• 1972: Twelve minutes to midnight. The US and USSR sign the first Strategic Arms Limitation Treaty (SALT I).
• 1974: Nine minutes to midnight. Arms control talks stall; India develops a nuclear weapon.
• 1980: Seven minutes to midnight. Small wars and terrorist activities grow, while arms-control talks remain stuck.
• 1981: Four minutes to midnight. Terrorism and repression of human rights grows, along with conflicts in multiple theaters around the world.
• 1984: Three minutes to midnight. Arms race picks up steam.
• 1988: Six minutes to midnight. The US and USSR sign a treaty limiting intermediate-range nuclear weapons.
• 1990: Ten minutes to midnight. Democracy flourishes in Eastern Europe; Cold War ends!
• 1991: Seventeen minutes to midnight. The clock leaps dramatically backward as the Cold War remains over, and the US and USSR announce signficant cuts in nuclear stockpiles.
• 1995: Fourteen minutes to midnight. Turns out that the peace dividend wasn’t quite what it might have been, as arms spending continues at Cold War levels. Fear grows of proliferation of nuclear weapons from poorly-controled facilities in the former Soviet Union.
• 1998: Nine minutes to midnight. India and Pakistan go public with nuclear weapons.
• 2002: Seven minutes to midnight. The U.S. rejects a series of arms control treaties and announces its withdrawal from the ABM treaty. Significant concerns about proliferation of nuclear weapons to terrorists.

So we’re right back where we started. If you don’t agree with the positioning of the clock as decided upon by the Bulletin’s board, you can always consult the Rapture Index for an alternative take on the imminence of Armageddon.

I don’t know about my co-bloggers, but reality has intruded and there hasn’t been much time for blogging this week. Instead, here is a photo of Angelina Jolie, Condoleezza Rice, and Hillary Clinton.

“It’s hard being a beautiful celebrity,” Clinton said. “I wouldn’t know, but I’ve got to imagine it has to be very difficult.”

Or if they do, they don’t admit it in public. I can’t recall a single instance of a physicist discussing their golf game.

But we are mad about baseball! In what seems to be anomously high numbers. (At least those of us raised in the US.) I’ve often speculated on the connection since baseball is a game of statistics and strategy. We’re not just mildly interested in the sport, we’re hard-core fanatics. One retired theorist in my group camped out overnight to get play-off tickets for the Oakland A’s, just in case they’d play in the post-season. He does this every year. Another guy will only score a game in pencil (once admonishing me for using ink). Another guy has a Red Sox watch and continously sports a Red Sox t-shirt. Another guy watches every Mets game on his laptop, even if he’s in Poland and it’s 3 AM. The more moderate fans simply keep track of the Giants daily box scores.

Me? I’ve been known to base travel plans on the schedule of my beloved St. Louis Cardinals. One of my favorite things is when a trip to Fermilab coincides with a Cardinals series at Wrigley Field. Today, I’ve dug out my lucky hat. I will start wearing it next Tues or Wed, depending on whether Philly or Houston wins the wildcard berth (I am hoping for Philly). I realize my mistake last year - I wore the wrong lucky hat. No wonder they froze! This year, I’ve got the real deal - the hat I wore during the ‘82 World Series. I’ve also pulled out my ‘82 World Champions t-shirt. So, you see, there is no way the Redbirds can possibly lose… Let the fun begin!

Update: As Janet pointed out in the comments - the secret is out: I can’t spell or type! We can all look forward to more “anomously” spelled words in my future posts.

Q: What does Bush think of Roe vs Wade?

A: He doesn’t care how people get out of New Orleans.

Well, I received a FedEx overnight package this morning, and as I had to write a lecture and then teach it, I did not open it immediately, and almost forgot about it until now. I was curious and a bit suspicious, since I’m not important enough to get things sent by FedEx out of the blue like that. Well, I opened it up to a pleasant surprise: Seed. The newly relaunched version. And it looks great!

What is Seed? It is a magazine put out by the Seed Media Group, and their motto is:

Science is Culture

Yes!

The whole world view expressed by the magazine (and the group, as far as I can tell) seems to be so in line with my fantasy of the way society should be in terms of being science-savvy, which I’ve talked about so many times in other posts on this blog. (See here, here, here, here, and comments of mine in the accompanying discussion threads too.)

Basically, its a glossy, hip, very designer magazine…. about science! There are interviews, articles of various sorts, and even a sort of photo showcase where there’s huge glossy photos, each with a chalkboard equation with a sentence associated to it. (Examples: The quantum mechanical spectrum of a particle in a 1D box; the running coupling constant of QCD -last year’s nobel prize by the way, etc…) There’s an “agenda” section, listing a number of upcoming science events, such as plays and exhibitions, around the country. And there are just lots of lovely huge glossy photos of beautiful things from art and science!

Many of the advertisements are science-ified too! The book reviews are about science books, and the tv shows and movies that are advertised or discussed have strong science themes. This is exactly the sort of thing I want to see more of. I really hope that I’ll see an office worker coming home from downtown reading a copy, instead of or alongside their copy of Los Angeles magazine, or the New Yorker, or (dare I say it) Los Angeleno, or anything….Then I’ll be even more excited. (As it is, I’m almost in tears with joy at this already…..and I have not even read a word of it yet; I hope I don’t have to take back some of those precious exclamation marks I’m using up….)

There’s a little article on science blogs, by the way (this was bookmarked with a post-it note: thanks, whoever, for sending it!). We’re mentioned, along with Pharyngula, Not Even Wrong, String Coffee Table and Quantum Diaries [Update: They mention LuboÅ¡ Motl’s Reference Frame too!]. Contributor Joshua Roebke talked about the aspects of the role of science blogs, quoting Peter Woit, LuboÅ¡ Motl, and our very own Sean Carroll (who is apparently one of the “main contributors” to CosmicVariance, although I note that the discussion they quote from is in fact a post of JoAnne’s …..ahem!).

And it gets better. Not only do they walk the walk, they talk the talk too. Here is an extract from the editorial welcome, which gets it right on the nose, as far as I’m concerned:

We believe that science matters, and will edit this magazine through that lens. We believe that a modern democracy requires a more science-savvy citizenry, and we will strive to be a tool in that transformation.

Yes! Yes! My daily mantra that I whisper reverently at my bedside every morning! To quote Sean and Risa: Someone’s been reading CosmicVariance! (I’m not serious of course, there surely must be others out there with my dream, right?)

More:

We will help you better understand the big topics in science today and how they are affecting our lives. We will showcase the vivid intersection of art and science, and let the images speak for themselves. We will be truly international, mirroring the borderlessness of science, and we will introduce you to the revolutionary minds driving these times.

Welcome to the new Seed.

Oh, Joy.

-cvj

As PZ and Chris Mooney point out, we finally see an article about evolution and creationism that gets it right — by making it clear from the outset that evolutionary theory is well-established science and supported by mountains of evidence.

When scientists announced last month they had determined the exact order of all 3 billion bits of genetic code that go into making a chimpanzee, it was no surprise that the sequence was more than 96 percent identical to the human genome. Charles Darwin had deduced more than a century ago that chimps were among humans’ closest cousins.

But decoding chimpanzees’ DNA allowed scientists to do more than just refine their estimates of how similar humans and chimps are. It let them put the very theory of evolution to some tough new tests.

If Darwin was right, for example, then scientists should be able to perform a neat trick. Using a mathematical formula that emerges from evolutionary theory, they should be able to predict the number of harmful mutations in chimpanzee DNA by knowing the number of mutations in a different species’ DNA and the two animals’ population sizes.

“That’s a very specific prediction,” said Eric Lander, a geneticist at the Broad Institute of MIT and Harvard in Cambridge, Mass., and a leader in the chimp project.

Sure enough, when Lander and his colleagues tallied the harmful mutations in the chimp genome, the number fit perfectly into the range that evolutionary theory had predicted.

Their analysis was just the latest of many in such disparate fields as genetics, biochemistry, geology and paleontology that in recent years have added new credence to the central tenet of evolutionary theory: That a smidgeon of cells 3.5 billion years ago could — through mechanisms no more extraordinary than random mutation and natural selection — give rise to the astonishing tapestry of biological diversity that today thrives on Earth.

Evolution’s repeated power to predict the unexpected goes a long way toward explaining why so many scientists and others are practically apoplectic over the recent decision by a Pennsylvania school board to treat evolution as an unproven hypothesis, on par with “alternative” explanations such as Intelligent Design (ID), the proposition that life as we know it could not have arisen without the helping hand of some mysterious intelligent force.

Kudos to Rick Weiss and David Brown of the Washington Post. And to everyone else: see, it’s not that hard!

Bitch Ph.D. is temporarily away, but loyal spouse Mr. B. has taken control and turned the site into — a science blog! Today he’s talking about the interesting issue of contaminating other planets with organisms from Earth.

Nowadays, when we send out space probes, we sterilize them. What little I know of this seems to indicate that our sterilization processes may be far from perfect. Regardless, the rationale for sterilization is sound — whether or not life exists or has existed at the probe’s destination, sending some of Earth’s life to the destination would potentially muck things up beyond repair. When we fear a spacecraft might not be sterile, we purposefully destroy it while it still has fuel enough to perform a fatal maneuver, as we did with the Galileo probe to protect the potential life on Jupiter’s moon Europa from earthy microbes possibly riding on the probe. These are real concerns that govern our use of current robotic space probes.

Suppose we didn’t worry about such things. Suppose there is life, an ecosystem, where we send a space probe. Suppose further, that some hardy bacteria or fungus stowed away on the space probe and is thereby introduced into the alien ecosystem. Chances are it will die out. However, there’s a slim chance that such stowaways could find habitat, potentially altering or even destroying an existing alien ecosystem.

I suspect it’s pretty unlikely that we will ever find anything worth of the name “life” on Mars or elsewhere in the Solar System, but I’m certainly no expert. If we did find anything, of course, it would be incredibly important, so I am happy to keep an open mind. (On the other hand, given the small chances, I agree with a colleague who says “It’s more important to look for supersymmetry than for life on Mars.”)

Still, one of the absolutely fascinating recent advances in the study of life’s origin has been the possible role of extraterrestrial chemistry. The classic Miller-Urey experiment demonstrated the possibility of creating amino acids by shooting sparks into a chamber designed to mimic the atmosphere of the young Earth. But apparently there’s good reason to believe that the Earth’s atmosphere wasn’t really like that in the experiment; in particular, it had more oxygen and less reducing compounds, and nobody has been able to make amino acids by zapping an atmosphere of that type.

On the other hand, conditions for synthesis of amino acids may exist in space! Interstellar clouds appear to be good places to create prebiotic organic compounds, or even proto-cells. It’s perfectly plausible that these could have been brought to Earth early on by crashing comets and meteorites. If so, it’s clear that the other planets would have received similar interplanetary donations of organic materials; no reason to believe that they necessarily evolved into life, but a fascinating possibility nevertheless.

I’ve just returned from vacation and am returning to the blogging stint with a pun. Being relaxed and jovial and all.

Physicists hardly ever take real vacations. You know the kind, where you travel to a place just for the fun of it. Usually we just sneak a day or two extra on a work-related jaunt. (Note that visiting relatives over holidays does not count as a vacation.) However, I’ve had an epiphany in my old (post-tenure) age: real vacations are actually good for you. This year a good friend helped the cause by having a wedding in a place called Sonning-upon-Thames. Who could pass up such an idyllic locale? It was great fun - a few days in the English countryside, the wedding, and then some time in London.

So what does a physicist do while roaming about London? Take a boat cruise down the Thames to Greenwich and visit the Royal Observatory and see the Prime Meridian, naturally. What else?

Turns out the Royal Observatory is a hot tourist spot. It was packed! No wonder, since it is billed as “one of the most important historic scientific sites in the world.” Everybody wants to see the Prime Meridian (Get the pun yet?), which is billed as ” the centre of world time and space.” Their website claims:

It was founded by Charles II in 1675 and is, by international decree, the official starting point for each new day, year and millennium.

Not much of a track record for starting new millenniums, I’d say, but, hey, if it brings in the crowds….

There is lots of cool historical equipment on display, including (i) a piece of Herschel’s telescope (a humongous piece of equipment he built in his backyard - apparently his wife was worried it would fall on the children and kill them). Herschel’s discoveries include Uranus and the solar wind, and (ii) roundish measuring devices (I haven’t a clue what they were used for) that Robert Hooke (a curator at the Royal Observatory) built for Emond Halley, the 2nd Astronomer Royal, of the comet fame. You can also view the Royal telescope which was used for scientific purposes until the 1940’s when the London sky brightness became too bright (wasn’t clear if this was during or after the Luftwaffe).

And, of course, there is the Prime Meridian. The definition of the Prime Meridian was actually an important scientific advancement in its day. It enabled accurate astronomical observations and ship navigation. It paved the way for the discovery of the abberration of light , where the earth’s wobble in its orbit gives an apparent motion to stars. It was previously thought that the stars wobbled from their true position.

So, the pun. You know how when children don’t understand something that is spoken, they assign words that they know to mimic the sound? Well, it seems that adults, when conversing on noisy London streets do the same thing. When I suggested that we visit Greenwich to see the Prime Meridian, my travel companion looked at me funny and replied that we had Indian food the night before. Seems that Prime Meridian sounds awfully like Primary Indian when spoken on a busy, noisy street. Ok, it’s a bad pun, but the checkout lady in the Royal Observatory giftshop doubled up in laughter, and I will never think of the Prime Meridian the same way again.