Saturday, April 30, 2005

Teri Heads to Iraq

My good friend Teri Weaver is a reporter, based in Seoul, for the military newspaper, Stars and Stripes. I know Teri from her time as a reporter on the Post Standard, here in Syracuse. She is a smart and fun woman, whose sense of humor is dearly missed around here.

Beginning in the last week in May, until July 4th, Teri will be in Iraq. She has an interesting and well-written post about her upcoming time in a combat zone on her blog, stonesoup. The whole post is worth reading. Even though it is mostly written just for her friends, I think Teri has taken time (or is just a natural) to capture the nuances of her situation in her writing. For her friends who are wondering what she'll be doing in Iraq, she tells us that
"I'll be embedded with troops all the time, probably mostly around Baghdad, but if it seems plausible, I might request to spend some time with troops near Ramadi or other parts of the country. I'll be able to choose my assignments and my locations, so I'll have to use my own judgment."
Take care of yourself Teri, and exercise that judgment well. I'll see you when we meet up in China in August.

Friday, April 29, 2005

What Do I Think About Religion? What That Guy Said.

I've been planning to write a careful account of my views on religion and its role in American life. I think this is a crucial issue because now, more than at any time in recent history, our society faces an increasing threat from the forces of irrationality. As scientists, and therefore daily practitioners, we are in a unique position to stand up and defend reason and logic. We can either speak out about the current social and political climate, or we can hide our heads in the sand and hope that it goes away. However, if we do the latter, we should not pretend that we didn't have a choice when sky actually falls.

I'll probably still write my piece, but it turns out that Richard Dawkins has hired an expensive psychic to fish around in my head and then has regurgitated my thoughts, in a more eloquent style, as his answers for an interview with So you can pretty much just read that.

As an example of Dawkins at his clearest (and, surprisingly, his most optimistic and conciliatory), he says
"You won't find any opposition to the idea of evolution among sophisticated, educated theologians. It comes from an exceedingly retarded, primitive version of religion, which unfortunately is at present undergoing an epidemic in the United States. Not in Europe, not in Britain, but in the United States.

My American friends tell me that you are slipping towards a theocratic Dark Age. Which is very disagreeable for the very large number of educated, intelligent and right-thinking people in America. Unfortunately, at present, it's slightly outnumbered by the ignorant, uneducated people who voted Bush in.

But the broad direction of history is toward enlightenment, and so I think that what America is going through at the moment will prove to be a temporary reverse. I think there is great hope for the future. My advice would be, Don't despair, these things pass."
I know that a lot of people with views on religion that are similar to mine do not like Dawkins. I've never understood this attitude. Dawkins is a hero of mine because he just comes out and makes the arguments in a clear, concise and unvarnished manner, whereas some people may prefer it if one sugarcoats the message. While I understand the sentiment, I feel that this approach can often obscure the point. This feeling is reinforced by the refreshing sensation I get whenever I read Dawkins. I get a similar feeling from reading Pharyngula.

The Gravitational Lens

In the comments section of Orange Quark, and a number of other physics blogs, I frequently see questions about the latest interesting paper that has popped up on the physics archive. Virtual spaces where one can discuss such papers are not well developed, but some do exist; for example, the CosmoCoffee forum. It seems to me that, with the increasing number of papers appearing daily, there's a market for sites with their own selection criteria, which winnow the number to a manageable one. Of course, one also wants the option to skim all the abstracts from four archives daily, as I do now.

As of yesterday there is a new contribution in this field. The Gravitational Lens is a short newsletter highlighting recent work in gravitational physics (all gravitational physics, not just waves) that is of broad interest. It will be posted every two months, and you can be notified of new issues by subscribing to the email distribution list.

The Editor-in-Chief of The Gravitational Lens is the talented Michelle Larson, who is the Deputy Director of the Center for Gravitational Wave Physics at Penn. State University. As a member of the editorial board, my role in this is to inform Michelle about any recent preprints (say, from astro-ph or gr-qc) that are related to gravitational physics, and lend themselves to highlighting, in a manner accessible to students and researchers in all areas of physics.

If you're interested in gravitational physics, I encourage you to visit The Gravitational Lens every couple of months and take a gander at what's new. If you see new papers on the archive that fascinate you, feel free to drop me a comment or email - perhaps they'll end up being discussed there.

Thursday, April 28, 2005

Most Scary: Altostratus or Cumulonimbus?

I didn't see this in the U.S. press, only in the Guardian. Did I just miss it? In any case, there's something pretty funny about it. You can read it for yourself, but I'll give you a taste with the headline
"Incoming cloud forces Bush into safe bunker"

Wednesday, April 27, 2005

An Eventful Day

Today is going to be very busy, and I'm quite excited about it, but won't get much blogging time. This evening is the opening reception for Stage I of the Cosmic Connections exhibit at the Milton J. Rubenstein Museum of Science and Technology (MoST) in Syracuse, a topic I've mentioned before. I need to prepare a few remarks for the opening, and get down there early to reassure myself that everything is ready for prime-time.

Much more importantly though, my Mum and Dad are arriving from England this afternoon. I'll be picking them up at the airport in a few hours, but first need to do some serious shopping. Middle-aged English people will wither and die rather quickly when removed from their homeland, unless their hosts are careful to stock up on life-giving essentials; most importantly tea. It's a bit like the Jurassic Park dinosaurs, that couldn't leave the island because they were dependent on a certain drug being delivered regularly. There are a few other important items such as bread, butter, bacon, Boddingtons,..., but tea is the important one (Just joking Dad!).

I've been looking forward to my parents' visit for months now, so I'm delighted they're finally arriving. Although I love living in the U.S. (most of the time), it's difficult to be so far away from my parents and brother, and visits like this are essential for us all. Now, I'd better go and check on our tea supplies.

Tuesday, April 26, 2005

Some Negativity About Negative Tension

Well, I'm going to take a break from going on about science under attack and return to some interesting physics, for today at least.

Yesterday we had an interesting seminar by Paul Smyth, who is a graduate student at Imperial College, London, studying with Kelly Stelle. Paul’s talk was titled “The Stability of Harava-Witten Space-times”. He was concerned with the implications of the negative tension branes required by some extra-dimensional models, both those arising from string theory and those appearing in some more phenomenological models. In Paul’s seminar, he discussed a detailed analysis of the energy of such braneworld space-times in 5 dimensions, and demonstrated that they are stable, using a non-perturbative positive energy theorem.

This, and related questions have interested me for a while, and Don Marolf and I wrote a paper that I really liked about a related physical setup. I thought it might be fun to recount the general ideas here.

An interesting possibility, that has seen new life in the last seven years or so, is that our three familiar spatial dimensions may exist as a submanifold of a higher dimensional space-time. Common to most of the modern incarnations of this idea is the condition that all interactions other than gravity be confined to our submanifold, or brane. Since departures from 3+1 dimensional gravity are relatively difficult to constrain compared to those of other forces, this permits significant freedom to modify the gravitational interactions in the extra-dimensional space. It is in this modification of gravity, and of the extra dimensions themselves, that recent approaches differ from one another.

In many of the proposed models, the hierarchy problem of particle physics – how is the large difference between the weak scale (100 GeV) and the Planck scale (1019 GeV) protected from the destabilizing effect of quantum corrections - is recast by bringing the fundamental mass scale of physics down to the weak scale. The large Planck mass observed on our brane is then a derived quantity, the size of which arises from the relatively large volume of the extra-dimensional manifold.

One specific hurdle that extra-dimensional theories must clear is that the brane-bulk system should be a consistent, stable solution to Einstein gravity. For those constructions that include negative-tension branes, this can pose a particular problem, although perturbative dynamical objections can be overcome by placing the offending brane at a point of special symmetry in the extra-dimensional space, known to aficionados as an “orbifold fixed point”.

Nevertheless, Don and I were interested in the possibility that there might be nonperturbative instabilities of such a space-time. We though there might be because of a simple (and, it turns out, naïve) thermodynamical argument.

This comes from the generalized second law of thermodynamics, which states that the total entropy in matter and black holes does not decrease. The entropy of a black hole is proportional to the area of the event horizon. Therefore, any process that leaves the entropy in matter fixed and decreases the total area of black hole horizons, leads to a violation of the generalized second law.

It is important to know that the area of a black hole event horizon increases when positive energy crosses the horizon, and decreases when negative energy crosses the horizon. Don and I were intrigued by the question: what happens if a black hole, initially far away from a negative tension brane, falls towards the brane and captures some of the brane within its horizon? One might expect that the generalized second law could be violated in this way, since the part of the brane that is swallowed by the black hole carries negative energy across the horizon.

Because the central issue can be muddied by questions involving gravitational radiation (and, frankly, because to go further than this seemed much harder) we considered a lower-dimensional system - a negative tension 1-brane in a 2+1 dimensional space-time – because gravitational radiation does not arise in lower dimensions. What we discovered in analyzing this system was something more dramatic (at least on the face of it) than a violation of the generalized second law.

In 2+1 dimensions, the only black holes are the so-called BTZ black holes, named after their original discoverers Maximo Banados, Claudio Teitelboim and Jorge Zanelli. These black holes arise only in space-times with a negative cosmological constant, the so-called Anti de-Sitter (AdS) space-times. This turned out to be particularly appropriate, because the kinds of brane-world constructions that people have worked on typically require an AdS space-time, for other reasons.

In the main part of our work (this is the bit where the cartoon caption reads "and then a miracle happens"), we made use of a certain amount of cute mathematics, involving the fact that both a BTZ space-time and a negative tension brane space-time can be constructed as quotient spaces of AdS. I certainly won’t go into this here. Rather, I’m going to hope that it suffices to say that this enabled us to construct a general exact solution describing the collision of a black hole and a negative tension brane at one of these points of special symmetry

What we found was catastrophic. The endpoint of this evolution is not, in fact, an equilibrium configuration, but instead is a space-like singularity (similar to the `big crunch' of closed cosmological models with only ordinary matter content). What we discovered, therefore, was a non-linear dynamical instability of gravitating negative tension branes at orbifolds – in effect, the entire space-time outside the black hole collapses when the brane is located at an orbifold fixed plane. Because BTZ black holes can form dynamically from the collision of matter, we also expect non-linear instabilities with negative tension branes in the presence of matter fields, even if no black holes are initially present.

The obvious question to ask is whether the same sort of singularity that we found in 2+1 dimensions also occurs in higher dimensional cases (which are of real interest). For a number of reasons, examples such as this are not sufficient to argue convincingly for a dynamical instability in higher dimensions. That's for future work, and I think I may even have interested Paul in the idea, at least a little.

It's worth mentioning that the ways in which orientifold constructions in string theory obviate this proof is a very interesting story in its own right. If you have the fortitude for it you can read about that in a nice paper by Don Marolf and Simon Ross.

So what is the bottom line of our work? It’s that an orbifold boundary condition may not, by itself, be sufficient to render negative tension branes stable. As a result, if use is to be made of negative tension branes in various models, it is necessary to show that the particular branes being used are immune from these effects. Within string theory this is probably not a problem, but phenomenological models might not be immune.

Well, that was a little more technical than usual, but since I've been thinking back over these ideas recently, I thought I'd provide a short overview. Come to think of it, there's a bunch of less technical and very fun things I'm itching to tell you about extra-dimensional models. I'll get into them soon.

Monday, April 25, 2005

Unlimited Love (for Influencing Desperate Scientists)

At Syracuse we have an aggressive Office of Sponsored Programs, tasked with getting our grant applications in on time, making sure they conform to the standards of the funding organizations, and informing us of new funding opportunities. Generally, they do a great job.

Imagine my reaction therefore, when I received the following today.
Secondary School Faculty Invited to Enter Course
Competition on Unselfish Love

Deadline: July 15, 2005

The Institute for Research on Unlimited Love - Altruism,
Compassion, Service ( ),
which was established through a grant from the John
Templeton Foundation ( ), has
announced "Unto Others: Scientific and Religious Perspec-
tives on the Love of Neighbor," a course competition for
secondary school faculty.

The competition encourages academically rigorous secondary
school courses that focus on unselfish love of neighbor as
a spiritual and practical ideal. The winning courses must
combine the study of unselfish love as understood within
(a) spiritual traditions and (b) scientific frameworks,
such as physics, cosmology, evolution, biology, political
science, the social sciences, and health.

Faculty in religious studies and/or theology, the
humanities, and the sciences are encouraged to apply.
Courses co-taught by two faculty members representing
religion and science might be especially compelling in
some cases, but team teaching is by no means imperative.
In addition to new individual course development, it is
possible to apply on the basis of refocusing an already
existing course on the theme of unselfish love with
significant attention to religion and science. In some
cases, several faculty teaching in an integrative core
humanities course might work together to include the
topic as a major and sustained theme.

Ten awards of $5,000 will be made.

Applicants can review the full course competition
description at the Institute for Research on Unlimited
Love Web site.
Before my upcoming post on topics like this, it might help to read Sean's take on a related issue. Day by day, it just keeps getting worse and worse. What we desperately need is an absurdly rich philanthropist, who wants to fund a prize for, and research into, the relationships between (not the compatibility or incompatibility between) reason and dogmatic belief systems. Of course, the outcome is already clear and doesn't agree with the preconceived notions of the Templeton Foundation.

Science, Scientists and the American Way of Life

Science, to me, is a strong uniting force. I've discussed, and often collaborated on, projects with people from a long list of countries, and never once in these discussions have issues of politics, race, economics, history or religion intruded on us. Sure, we talk about all these things over a beer afterwards, but the camaraderie we feel because of our common scientific goals, and shared experience in working towards them, ensures that these conversations are, almost always, constructive and civil.

For reasons like this, I am not one of the people who need to see U.S. dominance in science. I don't like the combative implications of the word, and I think its use misses the point of science as a unifying endeavor.

However, there are a host of economic, medical, educational, social and security reasons that the nation desperately needs a large, well-educated and well-supported scientific base. That's why the current turn away from science and reason and towards superstition and dogma in this country terrifies me. I don't think it is an overstatement to say that, if it continues unabated, this trend will bring about such a fundamental change in the intellectual constitution of the nation as to threaten to break the backbone of American life. I say this because maintaining a high standard of living for Americans is deeply connected to our country's investment in the scientific and technological research that will dominate the economy of the future.

Obviously, I have many longer posts planned about this, but I was galvanized to mention it today after reading two sobering posts on other science blogs. Over at Dynamics of Cats, Steinn Sigurdsson has a well-written piece about the inverse brain drain. Meanwhile, Gordon Watts writes eloquently about the impact of new restrictions on foreign graduate students on his Quantum Diaries blog.

Although there are many subtleties involved in what's going wrong in the U.S., ranging from the impact of the extreme right in politics, to the absurd way in which appropriations need to be reconfirmed year after year, the bottom line for the U.S. can be expressed quite simply (if not maturely); you snooze - you lose!

Sunday, April 24, 2005

Baseball, Physics and Science Journalism

We're three weeks or so into the baseball season now, and although the Cleveland Indians are only third in the AL Central, with an unremarkable 8-11 record, I'm still enjoying the feeling of summer in the U.S. that baseball brings, and that I've blogged about before.

Much has been written about the physics of baseball, and I am certainly no expert on it myself. However, there is a fascinating article about pitching in the current issue of American Scientist, the science and technology magazine, published by Sigma Xi, The Scientific Research Society. One of the authors, David G. Baldwin, seems like an interesting guy; according to his bio, he
"...pitched for the Washington Senators, Milwaukee Brewers and Chicago White Sox during the 1960s and 1970s. Following a 16-year professional baseball career, he earned a Ph.D. in genetics and an M.S. in systems engineering from the University of Arizona."
This is exactly the opposite of the way I'm planning to do it, as soon as this rotator cuff problem eases up and my contract with the Physics Department softball team expires.

I'm a big fan of American Scientist. They do a disciplined and careful job of covering some of the most interesting issues in modern science. One reason for this is their wonderful editor, Rosalind Reid. Rosalind was the Journalist in Residence at the Kavli Institute for Theoretical Physics (KITP) at the University of California, Santa Barbara, when I was spending my sabbatical there in late 2003. She ran a number of fascinating seminars and workshops about various aspect of science writing, spent a lot of time talking to the scientists, and was generally a fun person to have around.

The Journalist in Residence program is a tremendous idea. Previously, I've gone on at length about the importance of serious science journalism, and I think that any way in which we can provide journalists access to scientists helps further this goal. The nice thing about the KITP program is that it also provides a forum in which scientists can learn a lot more about the process of science journalism, and science writing in general. In my experience, this helps scientists to be better writers themselves, and helps them to appreciate the processes that science journalists go through in deciding whether a story idea is interesting and topical.

Now, more than ever, with science under attack, we need opportunities, such as this, to train with our allies.

Saturday, April 23, 2005

"Pop her ... Pop her again"

South Carolina lawmakers have a controversial (in South Carolina, apparently) bill in front of them. It's called the "Protect Our Women in Every Relationship (POWER) Act", and is designed to strengthen laws against domestic violence. The lawmakers were taped at their committee meeting discussing this. According to
"Rep. John Graham Altman asked why the bill's title "Protect Our Women in Every Relationship (POWER)" just mentioned protecting women.

Judiciary Committee Chairman Jim Harrison suggested calling the bill the "Protecting Our People in Every Relationship Act," or "POPER," ...

A voice on the tape is heard pronouncing it "Pop her." Then another says "Pop her again," followed by laughter."
The progressive Mr. Altman was later interviewed on WIS-TV and commented
"I do not understand why women continue to go back around men who abuse them," ... "I mean, you women want it one way and not another,"
Indeed. Imagine wanting both to be treated as equal partners with equal opportunities and, at the same time, wanting not to be beaten to a pulp by their husbands! I can almost hear the soft swish of knuckles against carpet as the above quotes were uttered.

Hey, "you women" in South Carolina! Can't you get rid of this guy at the next possible election? As Rep. Gilda Cobb-Hunter, a Democrat who sponsored the bill, said,
"And they wonder why we rank in the bottom on women in office and we lead in women getting killed by men,"

Friday, April 22, 2005

The Role of Science in Policymaking

As part of our celebration of the World Year of Physics, we had an unusual, but very good, colloquium in the physics department yesterday. The speaker was Mitchel Wallerstein, who is the Dean of Our Maxwell School. Mitch is a very experienced guy and a talented speaker. In the past he has been the Deputy Executive Officer of the National Academy of Sciences, and was Deputy Assistant Secretary for Counterproliferation Policy in the Defense Department. His topic was Nuclear Proliferation and Nuclear Terrorism: Two Dangerous Scenarios of the Post-9/11 Era. The talk was fascinating for at least two reasons. Firstly, it was packed full of information about nuclear weapons programs over the last 60 years, detailing which countries had ever had such weapons, which had started active programs but abandoned them, and which countries had at least openly discussed the option of setting up a weapons program. There were some surprising (to me) entries on that list, such as Sweden and Switzerland. The second reason I enjoyed the talk is that it gave one some limited insight into how issues like nuclear weapons, which physicists discuss frequently and heatedly among themselves, are viewed by authorities in a different sphere - that of public policy.

Mitch teaches a course next semester titled International Security and Asymmetric uses of Force, which sounds fascinating (if scary). I'm even toying with asking him if I might audit it and, if I did so, I would certainly blog about it. The course description reads
The end of the Cold War and the emergence of the United States as the sole remaining superpower—the only one with truly global reach and overwhelming technological superiority—has forced state actors and non-state actors alike to fundamentally rethink basic conceptions of international security. Indeed, perhaps the principal lesson of the recent military actions in Iraq, Afghanistan and the Balkans is that, for the foreseeable future, there is no prospect for deterring, much less prevailing over, the United States through conventional alignments of military power. Most state actors have now recognized that such direct confrontations are an almost certain recipe for the defeat of the weaker party or parties.
This course will explore the theoretical, doctrinal and policy implications of this new reality, focusing in particular on the emergence of asymmetrical uses of force as a rational response by those unable to counter the U.S. through conventional means. After laying the conceptual groundwork through an examination of the contemporary (and likely future) international security environment, the course will explore in detail a variety of asymmetrical threats, including the use of weapons of mass destruction (nuclear, biological and chemical weapons), cyber-attacks, attacks on civil infrastructure (transportation, communications, electrical grids, etc.), attacks on agriculture, and others.
The course will be taught as a seminar, and enrollment will be limited to encourage class discussion. Students should expect an extensive reading list and will be evaluated, in part, on the basis of their class preparation and participation. Each member of the class will be expected to prepare a policy memorandum to the National Security Council inter-agency process concerning a selected asymmetric vulnerability and to participate in a group presentation. There also will be a second major writing assignment at the end of the semester that will take the form of either a scholarly paper or a take-home final exam.
Not the kind of language we physicists are used to!

Yesterday morning I served on a Ph.D. thesis defense committee. The candidate was Belkis Cabrera, one of our best graduate students. Belkis worked for Don Marolf, studying various aspects of string theory and gravity, and has been out at Santa Barbara with him for the last year or so. She did a great job of the defense and we were delighted to pass her. However, I mention this here not because I want to talk about string theory, but because of what Belkis is going to do next.

For the next year she will be a Science Fellow at the Center for International Security and Cooperation at Stanford. This is a big step for Belkis. She is undoubtedly talented enough to continue on in a successful career in physics, but has decided that, for the meantime at least, she would like to get some experience in an entirely different realm. While I will miss Belkis for however long she is gone from the scientific research community, I am delighted to see such highly trained and scientifically knowledgeable people entering fields in which they may, ultimately, be able to have an impact on government policy. I'm even more convinced of the desparate need for such people after my disappointing experience listening to John Marburger speak, as I mentioned a few days ago. It is wonderful to educate people who go on to be professional physicists, doing fundamental research in our own, or other, fields, and pushing back the boundaries of human knowledge. As I've mentioned when discussing my own graduate students, this makes me very proud. However, I think we need to do everything we can to place people with a sound understanding of the scientific method in policymaking positions. Few people realize how much science pervades almost every aspect of our lives and, consequently, the potential for catastrophe when politics trumps good science.

I'm thinking of these issues particularly today, on Earth Day, while the New York Times is reporting that a Bush Administration's climate change study ignores many areas it is required to cover by law.

Wednesday, April 20, 2005

The Creationist Classroom

This via Aferensis. The Creationist Classroom is a short movie which, as far as I can tell, is promotional material for The End of Faith: Religion, Terror and the Future of Reason, by Sam Harris. It made me giggle, then cry.

Party Lines

When you're appointing someone to an important post, it's crucial to openly discuss the relevant issues, and not hold blindly to your dogmatic views. This rarely happens in practice of course. Nevertheless, yesterday, in the process to consider the nomination of John Bolton for U.S. Ambassador to the U.N., there was even some dissent from Republicans. For example, as the BBC reports,
"... in a fractious meeting on Tuesday, one Republican senator sided with Democrats demanding a fresh hearing to air allegations that Mr Bolton was a "serial bully" who intimidated junior members of staff."
"Senator George Voinovich, a Republican from Ohio and not one of those who had previously questioned the nomination, said he had "heard enough today that gives me some real concern about Mr Bolton".
It'd be nice if there were more opposition to out-of-date, contentious appointments, but you can't bank on it.

Tuesday, April 19, 2005

Comments on Orange Quark

I have just switched over to Haloscan for commenting, motivated partly by a request from Abbas Raza (of 3quarksdaily) for trackback capability. Unfortunately, as a result, blogger comments have disappeared from my blog. Thanks to all of you for your comments. I think your future ones will show up, so I hope you will continue to post your insights, advice and criticisms here.

Coming Soon to a Pharmacy Near You?

A pharmacist in California refuses to fill the prescriptions of AIDS sufferers, because that would be interfering with God's plans for gays. Another pharmacist, in Michigan, won't provide arthritis medication, because gnarled hands are God's way of stopping masturbation. A third pharmacist, in Florida, refuses to fill Viagra prescriptions, because, after their child-bearing years are over, God does not intend women to have to put up with the advances of their wrinkly old husbands.

(OK, these aren't real. I mean, they'd be ridiculous wouldn't they? I'm just blowing smoke up certain conduits. However, it's white smoke, not black, which means a punch line has been chosen.)

Now read this.

The Importance of Serious Science Journalism

On my last evening in Tampa, I sat up very late having a few drinks and discussing physics and related topics with Sean, Don Marolf, Wendy Freedman, Eanna Flanagan and a few other people. One was was K.C. Cole, who is one of the country’s best science journalists, and a wonderful writer in general - she was awarded the 1995 American Institute of Physics Award for Best Science Writing. You should check out her books, for example The Hole in the Universe: How Scientists Peered over the Edge of Emptiness and Found Everything. We were also joined by David Harris, who is a physicist turned science journalist, and who is Editor-in-Chief of the excellent Symmetry magazine, jointly produced by Fermilab and the Stanford Linear Accelerator Center (SLAC).

When I give public lectures, or speak to non-scientists at parties, or on airplanes, or at other social events, I find that people are, in general, fascinated by physics, particularly cosmology and particle physics. There seems to be a genuine hunger out there for direct contact with cutting edge research. A crucial role in feeding this hunger is played by well-written science reporting, of the kind that K.C. and a number of other writers provide. Their craft is not a simple one, and most certainly does not merely involve regurgitating what scientists write, but in a “dumbed-down” way. Rather, these people spend immense amounts of time agonizing over the physics, trying to understand the subtleties, avoiding the myriad pitfalls that can make a science article misleading, and interacting with scores of scientists to get the story right. I have a great deal of respect for what they do and think they provide a service that a civilized society deserves.

So you can understand why I find it so disturbing that K.C. feels that the number of dedicated science writers actively employed in the United States in dropping. To give just one significant example, Tom Siegfried has been let go as part of a large staff cut at the Dallas Morning News. Tom is an immensely talented science writer, who deftly tackles hard topics in his columns. As the American Journalism Review puts it, the paper
"... killed its weekly personal technology section and eliminated a weekly science section (firing three of six staffers) that had won numerous accolades and prizes. Those prizes include a National Association of Science Writers award that was being announced even as one of the winners, the esteemed writer and editor Tom Siegfried, was losing his job."
I think a reduction in the number of science journalists is a serious problem. It’s not just because I want people to read all about the cool things that are going on in my field (although I admit, that’s a small part of it). As our world becomes increasingly complex, crowded and interconnected, a basic understanding of science and technology is an essential requirement of an educated electorate. We are already facing a host of issues - stem cell research, genetic engineering, climate change, the energy crisis, weapons of mass destruction, missile defense - just to give a few examples, that cannot be understood without an appreciation of some basic scientific issues. At the same time, we are constantly bombarded with nonsense and pseudoscience that preys on the scientifically uneducated - astrology, alien abductions, homeopathy, magnetic therapies, perpetual motion machines and many, many more.

Already it is next to impossible to find a sensible discussion of science on network television, where many people get their “news”. If we lose responsible science writing from print journalism as well, I think that’s a huge blow. How are members of the general public supposed to make rational decisions about the policies of government if they don’t know the first thing about the technical facts that underlie many of them? It’s clearly impossible. Obviously all newspapers can’t employ a full time science journalist. However, if you are reading this and you live in a large city with a newspaper that you think doesn’t contain enough science and technology reporting, I encourage you to write letters to the editors. Tell them what you want and why it’s important. Other, like-minded readers may see your letters and join in the call for more quality science journalism.

In the in-flight magazine on my flight back home, there was a lengthy article in a section called Informed Sources, purporting to explain how acupuncture “works”. Much of the article is devoted to explaining the function of the Qi, or life force, that flows through all people. Check out this quote

"Writer James Swan had badly injured his shoulder while halibut fishing near Homer, Alaska. He wrote a column about treating his injury through acupuncture. `In traditional Chinese medicine,' he says, `an injury is seen as the result of multiple causality and a symptom of overall imbalance in Qi, caused by excessive or weak flows of Qi from or to internal organs.… From this perspective, when I was injured I was fighting seasickness, so my stomach meridian was weak. It was cold, and the choppy seas were somewhat frightening, causing weakness in the kidney meridian, as the kidneys are associated with fear. When you are frightened, your breathing shallows, producing less Qi, so the lung meridian would also be weaker. Accordingly, these external conditions made the shoulder weaker and injury more likely to occur.' "
Real science writers please help us - we need you now more than ever!

Monday, April 18, 2005

Favorite Quote of the Day

Via Chris C Mooney, from the description of the DVD, Arguments Creationists Should NOT Use, on the Answers Bookstore creationist website
"Bottom line: hold “facts” loosely and focus intensely on God’s written Word as the absolute guide to evidence interpretations!"
Well, at least they just come right out with it.

The Cosmology Report from Tampa

I’m on my way back from Tampa, blogging from the airport again. I have found this to be a very productive trip. A conference like this one, with a large number of attendees, has many talks and events. It is easy to spend the entire time rushing around from talk to talk, trying to see as many interesting topics as possible. However, I don’t get the most out of conferences that way. These days I pick and choose the talks I really need to see, plus a few at which I’d like to show support for colleagues or students. The rest of the time I spend meeting and discussing with colleagues. Sometimes these are preexisting collaborators and other times they aren't, but the conversations lead to new collaborations.

On this trip I attended a number of interesting talks; Rocky Kolb on Einstein’s Cosmic Legacy; Don Marolf on Quantum Gravity; Konstantin Matchev and Richard Schnee on Dark Matter; Rachel Bean on dark energy perturbations, to name just a few. Plus, as I mentioned in yesterday’s post, I also went to the Scientific Integrity in Government session.

I had a lot of fun in the Cosmological Constraints on Theories of Gravity and Fundamental Physics session, in which I delivered my invited talk on Theories of Cosmic Acceleration. What I enjoyed most about this session were the excellent talks by the other two invited speakers. Arthur Kosowsky (currently of Rutgers University, but soon to move to the University of Pittsburgh) gave a wonderful talk on the possibility that modifications of gravity might play a role in explaining the puzzles that one usually explains with dark matter. This idea usually goes under the name MOdified Newtonian Dynamics (MOND). First proposed by Milgrom, it invokes a change to the gravitational force law at a specific scale, altering the dynamics of galaxies and providing a stunning fit to galaxy rotation curves. This is by no means a popular idea, but it is fascinating that the fit to rotation curves is so successful. One reason that people initially did not spend much time on MOND is that, in its original incarnation, it is merely a phenomenological modification of Newtonian gravity and, as such, wouldn’t explain other observations that are explained by dark matter, such as gravitational lensing of galactic clusters. However, in the last year Jacob Bekenstein has formulated a covariant version of MOND. While his model is not exactly pretty, it has a honest-to-goodness covariant Lagrangian, and so one can, in principle, calculate all the implications of the theory, not just the rotation curves.

Hiranya Peiris from the University of Chicago then gave a tremendous talk on the Cosmic Microwave Background (CMB) radiation, describing how precision measurements of the fluctuations provide constraints on models of the early universe. Hiranya is the right person to do this, since she was the first author on the paper deriving these constraints from the WMAP data. .

Lots of fun physics packed into three busy days. Now back to Syracuse, where tomorrow it will be 77 degrees and beautifully sunny.

Sunday, April 17, 2005

Science and Government

In general I'm enjoying my time in Tampa and will post a longer description of the conference and its highlights when I return to Syracuse. This is just a short posting to get something out of my system.

I just got out of the session on Scientific Integrity in Government, in which the panelists were Kurt Gottfried, John Marburger and my friend and collaborator, Lawrence Krauss. I missed Gottfried's talk, but got there in time to catch most of Marburger's and Krauss'. Krauss discussed the appalling record of the current administration with regard to suppressing, twisting and misusing scientific data and opinion. Marburger is the White House Science Advisor and he faced a number of questions about this in the Q&A part after the talks. While he was gracious and polite, I really felt that his answers were dismissive of the well-documented and heartfelt concerns of many serious scientists. The questions from the audience were fine enough, but I don't think they got to the heart of the problem. I wanted (but time didn't permit) to ask Marburger a more wide-ranging question.

Lawrence had raised the point that 45% of Americans don't think that evolution is correct, and had pointed to well-known cases of government officials, both inside and outside the administration, who echoed that sentiment. I wanted to ask Marburger about the extent to which highly-placed people like himself, who believe themselves to be advocates for science, were consulted about issues such as this, and if so, how, if at all, they responded. This is something that is, quite honestly, a mystery to me. How does a scientist work in an administration headed by a president who thinks the jury is still out on evolution? I'm curious to know what he thinks about this and am sitting here somewhat frustrated by the whole session. Still, I feel somewhat better for having written this down.

Friday, April 15, 2005

Propagation of the Species

I’m blogging from the USAir club in Philadelphia airport (although it may only get published later), where, due to a delay, I have a lengthy layover on my way to Tampa. Despite the flight delay, I should arrive in Tampa by 6pm and intend to find a good, quiet restaurant in which to eat dinner while working on my talk for tomorrow.

Yesterday turned out to be a very good day indeed. I currently have three graduate students and one postdoctoral researcher working with me. It is true, I think, that individual physicists, be they students, postdocs, or faculty members, play the major role in determining the quality of the work they do, and therefore their career trajectories. However, there are, of course, many other contributing factors, and graduate or postdoctoral mentoring is one of them. This year, my postdoc, Damien Easson, and my senior graduate student, Antonio De Felice, have both applied for postdoctoral positions. While I have fully expected all along that they would be offered good jobs, I have still been a little anxious on their behalves (OK, fair enough, and for myself, because of my role in their careers) during the application season. As of yesterday though, I can relax, because they’ve both accepted excellent positions. In the fall, Damien will be a postdoc at the Institute for Particle Physics Phenomenology at the University of Durham in England, and Antonio will take up a postdoc at Sussex University, also in England. These are both great places to do particle cosmology and I am delighted.

Mentoring graduate students and postdocs is something that one is not formally trained to do in graduate school. This means that, often, one’s primary influence is one’s own advisor and this can either be a very good or a very bad thing. I consider myself to have been extremely fortunate, in that my Ph.D. advisor, Robert Brandenberger, is a wonderful role model, who treats all his students well and works hard to make their careers succeed. I know of many other people with the opposite experience.

I don’t really know where I sit on the spectrum of advisors, but I do know that I worry a lot about this part of my job. I find Ph.D. mentoring quite difficult. With my own projects I just have ideas and plough ahead into them. Sometimes they work out. Mostly they don’t. This is fine, of course, because it only involves me. However, with students, I continually worry that the projects I set them will turn out to be either trivial, or too difficult, or just silly. Indeed, on occasion, each of these results has happened.

In any case, this year I'm celebrating because everything has worked out well. Let’s see how things go in future years.

Thursday, April 14, 2005

Theories of Cosmic Acceleration

I fly out to Tampa early in the morning to give an invited talk on Theories of Cosmic Acceleration in the Cosmological Constraints on Theories of Gravity and Fundamental Physics session at the April meeting of the American Physical Society. Sean (of Preposterous Universe note) is convening this session, and it'll be nice to see him and possibly even make some progress on our ongoing projects.

I'll be discussing a variety of ideas about what could be driving the recently observed acceleration of the universe. There are three broad classes of approaches. The first is that cosmic acceleration may be due to a pure cosmological constant. The second assumes that the true vacuum energy of the universe vanishes, and that the dynamics of some exotic matter component, such as a scalar field, might be driving acceleration. This approach is like having a version of cosmic inflation happen in the late universe, and goes by the name quintessence. The final approach is again to set the vacuum energy to zero, and then to have a long-range modification of General Relativity be responsible for cosmic acceleration.

At various times I've worked on aspects of each of these approaches, but most recently the modified gravity one. Sean Carroll, Michael Turner, Vikram Duvvuri and I had our own idea of how to modify gravity to make cosmic acceleration happen (we later elaborated on it with my student Antonio De Felice and my postdoc Damien Easson). We considered adding inverse curvature terms to the Einstein-Hilbert action so that when all matter dilutes away, the universe cannot approach flat space-time. Our initial model was constructed to affect the universe on large scales (the Hubble size). However, gravity is a tricky topic and it turns out that there is also an unavoidable effect at smaller, solar-system scales, which leads to critical constraints on our model. One such constraint arises from precise measurements of the timing of communications signals from the Cassini mission (man those robotic missions do some good science!). There have been some suggestions that modifications of our models (using more complicated versions of what we did, while trying to retain the main idea) can evade the constraints. However, I actually don't see how these can be correct and, at present, I don't know how to overcome the obstacles. My collaborators and I are fine with that though - this is how science is meant to work.

There are some other suggestions of how to modify gravity to obtain late-time cosmic acceleration. One belongs to the fiendishly inventive Gia Dvali and collaborators, who have an extra-dimensional brane-world model, known as DGP gravity, in which gravity becomes five dimensional at very large distances. This model can also exhibit shorter-range effects in addition to the large scale ones that provide cosmic acceleration. However, my understanding is that these models evade current bounds, but may be testable with precision tests of gravity in the near future. This has been worked on by, among others, my good friends Glenn Starkman and Arthur Lue.

I'll be discussing all these ideas, and more, in my APS talk, assuming that I finish writing it in time for the Saturday afternoon session. It's going to be a busy flight tomorrow.

Wednesday, April 13, 2005

Cosmic Connections

This afternoon I'm heading down to the Milton J. Rubenstein Museum of Science and Technology (MoST) in downtown Syracuse, to walk through an upcoming exhibit. I am a co-PI on a $600, 000 National Science Foundation grant to create an entire cosmology exhibit, called Cosmic Connections, which will be a permanent part of the museum.

Stage one of this project is now almost complete, with the grand unveiling in two weeks' time. For the past couple of months a lot of construction has been going on in the space and, since I am really involved more with the conceptual side, I haven't had a good look at it. If the exhibit looks anything like the elaborate models we had, then I'll be very excited. To ensure a professional and coherent design, we collaborated with two classes of students in the design program at Syracuse. Getting physicists and designers to work well together was a challenge, but I think it worked out pretty well and we learned a lot from each other.

The opening reception, at which I'm giving a short cosmology talk, is on the evening of April 27th, and I intend to post some photographs of the exhibit soon afterwards, with a more detailed explanation of what we've accomplished so far. What I really want to show you are the fantastic glass sculpture of the galaxy that we have, and the hologram of large-scale structure in the universe (although this one will be challenging). The latter provides a three-dimensional-looking representation of an actual N-body simulation of the distribution of dark matter. I think they both look fantastic, and I'll give you all a chance to judge them for yourselves very soon.

Tuesday, April 12, 2005

The Abridged Bérubé

You've got to see this to believe it! After a pants-round-the-ankles paddling by Michael Bérubé in an email "debate", that odious whackjob David Horowitz, champion of the "Academic Bill of Rights" Trojan horse, posted an edited version of the exchange, which, let's say, doesn't accurately convey the rosy glow left on Horowitz's cheeks.

Fortunately Michael kept the entire text of the debate and has posted it on his blog. Horowitz now claims this was a mix-up and says he'll post the entire version soon (with another rejoinder from Horowitz. Does Bérubé get to reply to this additional statement?) I don't believe his explanation.

Monday, April 11, 2005

In British Politics, Be Careful What You Wish For

A few posts back I discussed how torn I am about the upcoming British general elections. My central issue is the judgment that Tony Blair deliberately misled the public about the evidence on which the war in Iraq was based. Max Hastings, a "wet Tory" by his own description, has a comment in today's Guardian in which he argues that it may not even be in Labour's best interests to win reelection in May.

His argument is based on a mix of historical analogy and current political analysis, but boils down to the idea that people eventually get sick of being governed by one party, that the party in power uses up all its good ideas, and that winning a third term can result in a deep dislike for a party rather than a two-term itch. As Hastings sums up
"Our system of parliamentary democracy cannot make provision for limiting party terms. But, just as the Tories today lament that they did not lose the 1992 election before the public grew lastingly sick of them, so some younger Labour MPs may find themselves boring colleagues in the 2010s with their regrets about failing to drop the 2005 one."
I can't say I completely buy the argument. I don't think it's inevitable that a governing party will run out of ways to keep a country moving forward. However, this feeling does rely on the electorate being capable of making a reasoned distinction between the differing ideas of opposing parties and not giving in to political ennui. OK, when I put it that way it's easier to see what he means.

Saturday Morning Physics

In late 2002 I began a new public lecture series in Syracuse, called Saturday Morning Physics, which is designed to share the ideas and excitement of cutting edge modern physics with people with no previous science education. I was motivated to do this after a visit to the University of Michigan, during which I attended one of their lectures of this type and was stunned with how popular it was.

The Syracuse incarnation is now a regular event, with a growing audience drawn from local high schools and the public in general. I spent Saturday morning running the tenth lecture in our series. The previous nine
  • Searching for Ripples in Space-time: Fulfilling Einstein's Vision
  • Modern Cosmology and the Building Blocks of the Universe
  • The Case of the Missing Antimatter
  • Black Holes: the One Hour Tour
  • `Catch a Falling Photon, Put it in Your Pocket.': The Science of Solar Energy
  • Chaos: Snowfall, Dirty Dishes, and the Paths of Planets
  • Astrochemistry and Astrobiology: Exploring the Chemical Factories of Interstellar Space
  • Soft Matter: Geometry and Materials
  • Physics and Society: from individual Enabling Technologies to Global Crisis Communications
have been quite successful, drawing audiences of between 80 and 150.

Saturday's talk was something a little different, as it was also part of our World Year of Physics celebration. My colleague Peter Saulson, who is the spokesperson of the LIGO Scientific Collaboration and is a wonderful speaker, gave a masterful lecture titled "A Celebration of Einstein's `Miracle Year'". Peter described Einstein's 1905 papers on Brownian motion, on the photoelectric effect and on special relativity, explaining the essential physics, the revolutionary nature of the papers and the lasting impact that these insights have had on physics and technology. If you would like to read an eloquent description of the science and its implications, take a look at Brian Greene's editorial, One Hundred Years of Uncertainty, in Friday's New York Times.

Peter ended the lecture in a novel way by reporting to the audience about how individual Syracuse Physics professors felt that the three 1905 papers influence their research today. He had surveyed most of the faculty and the responses were quite interesting, pointing out the connections to cosmology, condensed matter physics, particle physics and solar energy research.

I was delighted that one of my colleagues chose to comment on Einstein as a model for the public and political roles that she felt scientists should play. Some of the battles to be fought today are the same as those that faced Einstein's generation, but there are some new ones for which we need to organize. An important example in the U.S. right now is the need for scientists to speak out when faith and belief are replacing skepticism and reason as the basis for government policy. Pharyngula has posted the text of Donald Kennedy's wonderful editorial about these issues in the most recent issue of Science. It's quite well written and, although the need for such an editorial deeply depresses me, it is a relief to see an increasing number of high profile scientists, educators and journalists taking on this cause.

Sunday, April 10, 2005

Huxley on the Scientific Method

Yesterday's 3quarksdaily directs readers to a survey, reported in The Guardian, in which 250 scientists were asked, "What is the one thing everyone should learn about science?" The story is a fun read, with some scientists making quite moving and profound statements. Faced with the current assault on science and reason by our administration and its extremist backers, I found reading sensible response after sensible response from my fellow scientists wonderful therapy.

The response from Michael Baum, Emeritus professor of surgery at University College London, refers to one of my favorite quotes from Thomas Henry Huxley ("Darwin's Bulldog"):
"... the great tragedy of Science–the slaying of a beautiful hypothesis by an ugly fact"
What an exquisite turn of phrase.

Friday, April 08, 2005

I'm a Firefighter's Plaything

This morning I was talking to my wife, Sara Errington, after she arrived home from work, and it occurred to me that I've never mentioned her in this space. So I'm going to come right out with it here - I'm a firefighter's plaything!

Sara and I met when we were both graduate students at Brown University; me in physics (obviously) and Sara in history. Sara knew from early on that she didn't want to be an academic (or, as she puts it - "I can't stand most students") and so, after completing her Ph.D. in early American history, she became a journalist and worked for the Lorain Morning Journal while we lived in Cleveland. After we moved to Syracuse, she landed a nice job with the Post Standard, where she worked for four years. Her analytic, research and writing skills were well suited to journalism and she enjoyed this line of work. However, this isn't the end of her story.

During the first few months at the Post Standard, she was covering an accident scene at which there were volunteer firefighters attending. She commented about what a good time they seemed to be having and they had an application in her hands within a couple of days. She has been a volunteer in DeWitt ever since, rather rapidly becoming a Lieutenant there.

Sara realized relatively quickly that she loved the fire service so much that she wanted to do it full time. After acing the written test two and a half years ago and waiting out a two-year hiring freeze, she was accepted into the Syracuse Fire Academy in August 2004 and graduated in mid-November of that year. She is now one of only three female firefighters in the City of Syracuse (out of 390), and is based at Station 18 in the Valley area.

Needless to say, Sara's path from historian to journalist to firefighter is pretty unusual, even more so because she is a woman and the fire service is still a predominantly male environment. However, her colleagues treat her very well (for the most part) and it is hard to describe how happy she is with her career. I can also report that life's a blast as a firefighter's guy.

Thursday, April 07, 2005

Cochlear Implants

The Physics colloquium here at Syracuse this week was by Ian Shipsey from Purdue University. Ian is a high energy experimentalist who used to be a postdoc at Syracuse well before I came here. His colloquium was an extremely unusual one, titled “Bringing Hearing to the Deaf - Cochlear Implants: A Technical and Personal Account".

In 1989, Ian lost his hearing as a result of intensive antibiotic treatment to protect his immune system after chemotherapy to cure him of Leukemia. He recently received a cochlear implant, which is a remarkable piece of science and technology that can restore neural function to the ear and allowed him to hear for the first time in fifteen years. Between becoming deaf and receiving the cochlear implant Ian and his wife (Daniela Bortoletto, another physicist and a former Syracuse graduate student) had a daughter and, until two years ago, Ian had never heard her voice. Now all that has changed.

Ian discussed in great detail the physics behind the working of the ear and it was truly fascinating. The combination of the passive way in which sound is transferred between the various components of the ear and the active way in which it is amplified through tiny electrochemical motors is a bioengineering marvel. I knew very little of all this and came away significantly educated about the physics and in awe of the tremendous amount of work that has been performed to elucidate the details he discussed.

The second half of Ian's colloquium was about how cochlear implants function. He described their history, the electrical engineering and psychophysics involved, and the clinical evaluation of their performance. He also discussed his personal experience in getting and using his own cochlear implant, as well as making some comments regarding the social implications of implantation.

Ian gave a similar talk at Fermilab lat year, and you can download the slides or watch the video of that talk. I encourage you to do so if you have time; it is a fascinating description of the physics of the human body.

Wednesday, April 06, 2005

People Love Cosmology

I finished my Frontiers of Science talk a couple of hours ago. Apart from a few AV hassles at the beginning, things went very well and I had another very positive experience talking to the general public about science. My audience consisted of university students, local people interested in physics and a set of high school students brought to the lecture by their teacher. There were 45 minutes of questions at the end, ranging from general ones about the nature of dark matter and dark energy to one very specific question about Calabi-Yau manifolds. In general, people seemed to get the point about the connections between cosmology and particle physics. I decided not the give them this bad news.

In part of my talk I discussed the contributions that the soon-to-be-euthanized Hubble Space Telescope has made to modern cosmology. Interestingly enough, at the end two women came up to talk to me. They were the mother and grandmother of one of our students and, it turns out, the wife and mother of the launch director of the Hubble mission. They said it was great to finally understand why what he did was useful. Never mind, we appreciate him!

Tuesday, April 05, 2005

Frontiers of Science

I hardly have any time for blogging today. Tomorrow evening I'm giving the Frontiers of Science lecture here at Syracuse. This is a popular-level lecture and my title is "Modern Cosmology and the Building Blocks of the Universe". The talk will be some kind of amalgam of an existing public lecture that summarizes much of 20th century cosmology, a second that I gave in May 2004 as the public lecture at the Dark Side of the Universe workshop at the Michigan Center for Theoretical Physics, and some material that I'm still putting together. As you can tell, this is not exactly finished yet (hence the lack of blogging time). On the plus side, I do have an abstract though:

"No two ways about it - the universe is really, really big! If we want to understand it, we need to know about nature on very large scales. On the other hand, I think we'd all agree that atoms and their constituents are extremely small! To understand them requires us to know about nature on very small scales. The challenge of modern cosmology is to use these seemingly different aspects of physics to explain how a young, hot, small universe became the old, cold, huge universe we see today: to understand the physics of the Big Bang. In the first part of this talk, we will tour the major ideas of 20th century cosmology. We will see that a series of remarkable experiments completed over the last decade provide convincing evidence that the universe is roughly 4% ordinary matter (the stuff of the periodic table), 26% dark matter (the nature of which is mostly unknown), and 70% dark energy (the nature of which is almost completely unknown). In the second part, I will try to give a picture of how cosmologists are trying to address these questions, requiring the physics of the large and the physics of the small to work together."

Monday, April 04, 2005

The Ditch Blair Project

The Guardian is reporting that tomorrow morning Tony Blair will formally ask the Queen to call a general election on May 5. This comes after a Guardian/ICM poll showed Blair's government holding only a slim three-point lead over the Conservatives. This puts me in an incredible bind.

In the U.S., I would have deeply opposed George W. Bush even if he hadn't led us into Iraq, because his social and economic policies are, in my opinion, designed to make the lives of working people in America worse and worse. If I could vote in the U.S., I would be a Democrat, for all their faults.

In Britain, however, I vote Labour, because that party has traditionally been the one whose economic and social policies have been the best for the working class, from which I proudly hail. (You can't imagine the party I'll hold when Margaret Thatcher finally croaks.)

Despite all this, the prospect of re-electing Blair is a difficult one. I cannot understand his stance on Iraq and feel deeply betrayed by his government. It is disproportionately the children of the poor who end up fighting wars and, although they are sometimes necessary, for a Labour government to send our soldiers off to fight on such flimsy evidence is hard to forgive.

I can't imagine ever voting Conservative (unless their primary policies become those of the Labour party), but it is hard to imagine rewarding Blair for his dreadful lack of judgment (and I'm being kind here). I really don't know what I'll do. I might consider voting for a third party, but I don't want to look back and be the British equivalent of a repentant Nader voter.

Doubtless I'll mull this over further in this space as the date nears.

Sunday, April 03, 2005

Opening Day

I have found it quite hard to get into American sports, but when I lived in Cleveland I became hooked on baseball. We lived less than a mile away from Jacobs Field and I went to a lot of games. Two were particularly memorable.

The first was when my friend Dan Akerib (a dark matter experimentalist) and I were lucky enough to watch Cleveland come back from eight runs down, sitting just eight rows behind home plate. Wonderful!

The second was during an 80th birthday fest for Les Foldy, a famous particle physicist and great guy, who has since sadly passed away. Attending the fest were Gerard 't Hooft (Nobel Prize 1999), Frank Wilczek (Nobel Prize 2004), James (BJ) Bjorken and Mark Wise (no slouches either). The owner of the Indians gave his suite to twenty-two of us from Case Western, including these guys, for a whole evening. It's a lot different up there. In particular, I don't ever recall being able to get the attention of the dessert and liqueur cart from the nosebleed section.

Today is opening day, and the Indians aren't playing. However, since the Yankees are (and against my second team, the Red Sox), I can still enjoy rooting against them. The most important thing about all this, from my perspective, is that it's starting to feel like summer in the North East.

Saturday, April 02, 2005

Cosmic Acceleration from Topological Defects

A few days ago I posted a preliminary description of topological defects, as a prelude to a brief discussion of how they can lead to cosmic acceleration. In that post I focused on an analogy between field-theoretic systems and a simple mechanical system consisting of pencils, stood on their ends on a table, and connected to their nearest neighbor pencils by springs. In a field theory, it is (usually) a scalar field that picks out a specific direction in field space, spontaneously breaking the overall symmetry of the theory. In the pencil example, any direction in the plane is a vacuum, but when a pencil picks out just one, it breaks that symmetry (in this case rotational invariance in the plane).

Just as with the pencils, if the space of vacuum states, from which the field chooses, is topologically nontrivial, then the field can pick different vacua in different regions of field space. This can then result in a small region of space in which the field is not in the vacuum and, in fact, takes the value it did before the symmetry broke. We say that this region, the core of the defect, is in the unbroken symmetry phase.

Because the core is not in the vacuum, it is a region of approximately constant energy density, which is rendered metastable by topology. In broad terms, for a lone defect, this means that the core is like a small region of cosmological constant and the rest of space is in the vacuum. For example, for an infinite straight string, the energy-momentum distribution is like having a cosmological constant in the direction along the string.

If defects form during phase transitions as the universe cools, which is what we expect if the relevant field theory has the appropriate topological features, then networks of defects will form. Under certain circumstances, the defect network will frustrate; that is to say that it will form a frozen network, which you can imagine as a mesh-like configuration pervading space. Since the physical orientations of defects are random as one traverses the network, one can average over them to obtain a homogeneous, isotropic distribution of energy density on large scales.

How does this energy density evolve? You might expect that because each defect behaves, in part, like a cosmological constant, this might lead to an overall cosmic acceleration. The actual answer depends on the dimensionality of the defect. In a gauge theory one obtains the following; a system of magnetic monopoles evolves like regular matter; a network of cosmic strings evolves like a fluid with equation of state parameter w=-1/3, which is precisely on the border between decelerating and accelerating cosmologies; and a network of domain walls yields w=-2/3, which would indeed cause cosmic acceleration.

Current measurements of the equation of state of dark energy disfavor an equation of state parameter so far from w=-1. However, it is still possible that a frustrated defect network is part of the cosmic energy budget, and it is fascinating (to me at least) that nonperturbative solutions to particle physics theories can have such a profound effect of the evolution of the universe.

Friday, April 01, 2005

My Grandad

My Dad just directed me to a web site titled Prisoners of War, which is "a tribute to those men who were imprisoned in Stalag 18A, Wolfsberg, Austria from 1941 to 1945". One of these men was my paternal Grandfather, Peter Trodden. My Dad has posted an account of what happened to my Grandad, which I found incredibly moving and sobering. We all know that war is terrible, but when you're reading about someone you knew and loved, it's worse. My Dad's account begins
"Peter Trodden worked as a butcher and had also boxed as a professional. He lived in Altrincham, Cheshire, although he was born in Bury, Lancashire in 1916. He volunteered at the outbreak of war and became a gunner in the Royal Artillery.

On 15th November 1940 his battalion left Paignton for the ill-fated battle of Crete.

They travelled by way of Liverpool, Freetown, Durban, the Suez Canal and Beni Usef, Cairo where they had three weeks intensive training. Then via Port Said and on to Crete, where they arrived on 30th January 1941. As is well documented, things did not go well and on 15th July 1941 he and many others sailed for Salonika on the Yalova as POWs. ..."
There's a lot more if you follow the link above. This might not be that interesting to anyone outside my family, but who knows.