Me and The Priests

In 1795 the British government decided to build a beautiful Catholic seminary in Ireland to train priests. If you know much about Irish history, you will realize how strange this sounds: the Brits hated the Catholics, and oppressed them for hundreds of years. Why on earth would they go out of the way to build a nice seminary for them?

Well, this is a classic (and rather brilliant) case of keeping your friends close and your enemies closer. Since there were no seminaries in Ireland, the Irish typically went to France for their religious education. Long about that time, the French were having this thing called a revolution where they were cutting off people’s heads – particularly those in the ruling class. The Brits were justifiably afraid of having folks come back to Ireland with ideas of revolution, so they decided to keep their enemies closer by building a nice seminary in Ireland to keep them at home. In this way St. Patrick’s College was established in Maynooth Ireland, just outside of Dublin, and it has been operating as a seminary, training priests, ever since.

After a few years they decided to expand the seminary to become a broader university and the location eventually became what is now the National University of Ireland at Maynooth. By the auspices of Science Foundation of Ireland, I am officially a visiting professor at NUIMaynooth for some number of weeks per years in 2009 and 2010 (This is a complex arrangement that we started negotiating back when I was still at Bell, and it is officially so confusing that I have no idea of any of the details by this time).

At any rate, for this particular visit to Maynooth, all of the low budget “regular” rooms have been booked, so I’ve been staying in the guest rooms of the seminary. I was told that there would be a conference of Bishops during my stay, and that I would have to be extra quiet so as not to disturb them. So every morning at 7 am, I make sure to crank the Led Zepplin at 9 on my stereo instead of 10.



Here is a good picture of the building where I’m staying. It has 20 foot high ceilings everywhere (that is close to 7 meters, for the international audience) and the hallways are close to the same width as height. You could march a team of clydesdales down the hall in parallel without them feeling at all cramped. I’m not sure why the monks in 1795 decided they needed to march horses down the hallway in parallel, but apparently they did. You might even be able to march an elephant down the hall if you tried.

As you can see in the photo, the windows are extremely tall – probably 15 feet high. The room I’m staying in is sparsely decorated. Just a large bed and a tiny table, and lots of extra (wooden) floor space – which I could use to play soccer, I suppose.

Standing at the position where the above photo was taken, if you turn around 180 degrees, you see the main building of the seminary in this picture --- which also houses such crucial things as the student cafeteria in the great Hall (which I would have once called Harry-potter-esque, although now I probably would just call it Oxford-esque).


I’m still entertained that there is a strict division in the cafeteria –-- one section is roped off and labeled “reserved for seminarians.” Perhaps they are afraid of the corrupting influence of evil people like me (I do have horns, you know).

Anyway, returning to the photos above, there is a legend that it is bad luck for undergraduates to walk down the path in the center of these pictures. The source of this legend is thought to be that faculty members would sit at the sides of this path and think deep thoughts when the weather was nice, and whenever undergraduates bothered them by walking down the path, the faculty got upset and made the exams just a bit more difficult.

Although the area around the university is pretty, most of it is not ancient like these two pictures. The campus is split into a north and south half divided by busy Kilcock road. There is a walking bridge over this road, with signs indicating that one should not cycle over the bridge. Every one of these signs has succumbed to graffiti by this time. My favorite one now says "No Cycling, Sasquatch". Must be the seminarians with the sense of humor.

My Delsey Suitcase

I bought my rolling Delsey suitcase almost a decade ago. It is one of those rolling small black bags that you see in airports all the time. When I bought it, it was the largest suitcase size that was still small enough to fit in the carry-on – which made it the ideal suitcase. However, sometime in the intervening years, the airlines slightly decreased the size of a bag that you are allowed to carry-on (even though the suitcase will certainly fit, they now tell me it is too large almost always), and now my Delsey bag is instead the smallest suitcase that you are not allowed to carry-on to an airplane. As a result my ideal suitcase is now a bit less than ideal. But I haven’t gotten around to replacing it yet.

Last week, I was in Ireland, attending this conference, and I am staying Ireland again this week, but since I had to be in Cambridge to sit on a thesis committee on Monday, I went home to Oxford for the weekend. Arriving at Dublin airport, and checking my Delsey suitcase at the British Midland International airline (BMI) counter, I happened to comment to my friend Gunnar Moller that his carry-on suitcase was the ideal size, whereas mine is now not ideal. I think “not-ideal” is a bit of an understatement. Somehow in the course of the one hour direct flight from Dublin to London, BMI managed to lose track of my suitcase. Two days later, it still has not turned up. While I’m not crushed to have lost the Delsey (which, admittedly, was no longer ideal), I’m quite annoyed to have lost the entire contents of the suitcase. The people at BMI tell me that if it doesn’t show up within 5 days, they file it as lost and I have to negotiate with their luggage compensation people. By then, the underwear situation may start to get a bit critical. Despite my resistance to such things, I may need to actually go shopping.

PS: L’shana tova. (Happy new year in the Hebrew calendar, thus begins the year 5770)

Update Monday: Still no suitcase.
Update Tuesday: Still no suitcase.
Update Wednesday: Still no suitcase. BMI instructs me to contact the Luggage loss department. Ugh.
Update Thurdsay: Alas...

Shelob, Aragog, or Charlotte

According to the British Arachnid Society, there are no spiders in the UK that eat people. However, looking at the rather large spider who has taken over my backyard in Oxford, I have my doubts.

You can see her for yourself in the picture. For reference, the garbage can in the background is a full size 40 gallon container (150 liters). The spider is about 2.5 cm from fang to spinnerette –a bit over 5cm long if you include the legs. I’m not positive, but I think she is an Argiope Bruennichi, based on the size and the striped legs, but the body doesn’t look quite like the pictures I find online (Any spider experts out there want to comment on this one?).

I had known about the spiders of unusual size (S.O.U.S.) in this country even before I moved here: I had had a frightening close-encounter with a British SOUS on one of my visits to Oxford before moving here (a story for another day). Admittedly, The British spiders aren’t nearly as nasty as the beasts that live in Australia: for example, the Funnel-Web can deliver enough poison to kill a human within 40 minutes, and can bite through most canvas sneakers. This seems to me to be a good reason to avoid the whole continent.

Despite the favorable comparison to the bigger and badder Aussie variety, the somewhat less deadly British critters still give me the creeps. There is some evidence that being afraid of spiders is learned behavior, and children do not naturally have this fear. Nonetheless, the trope of the deadly spider is certainly a common one: Aragog, Shelob, Charlotte. Ok, maybe Charlotte was not supposed to be so threatening, but E. B. White conveniently left out the part of the story where Charlotte mates and then kills and devours her lover. (She lays eggs, so it probably happened). Probably White was censored by his editors since it is a children’s book and one wouldn’t want them reading about spider-sex.

The lifecycle of most of the large British spiders is such that they are born in the spring, they grow through the summer, and get extremely large in the fall just before they mate, lay eggs, and die. I’m traveling for the next three weeks with only one more two day stop back in Oxford, and I’m hoping that Shelob in the backyard will hurry up and get on with the mating, laying eggs, and with luck she will be stone-cold by the time I get back. As far as encouraging the mating part, I left a disco ball in the window and some incense in the backyard.

Condensates - the Borg of Physics

Many phases of matter consist of some highly organized arrangement of constituent particles. In many such cases of interest so-called “condensates” have the property that every particle contributes to the overall collective quantum properties of the whole. Not to make too dorky an analogy for an already geeky subject: you might think of it as the Borg from Star Trek – a communist collective of particles each contributing to an overall unison.

Once you have an organized ground state, it is a natural question to ask what the low energy “defects” of this ground state, (the quasiparticles) look like. Indeed, in most cases, it is these quasiparticles that determine the interesting physical properties of the phase of matter in the first place. All of the particles have fallen into line perfectly making a featureless background, and what you notice most in the experiments are the few regions where something different is going on. A next question to ask is what happens when you have a lot of these defects. Can the defects now start forming their own organized collective – their own Borg?

At the Quantum Hall workshop at NORDITA this month there has been a lot of discussion of what kind of condensates, or new phases of matter, can form from collections of quasiparticles in fractional quantum Hall states. This is an old question that dates back to the very earliest days of quantum Hall effect. As many people reading this might already know, very shortly after the discovery of the nu=1/3 fractional quantum Hall effect, Bob Laughlin gave a beautiful theoretical explanation of how electrons in high magnetic field can condense into a new quantum phase of matter (a Borg of electrons), thus explaining the experiment. However, very soon thereafter, additional quantum Hall effects were discovered (the 2/3 effect, the 2/5 effect, and so on). Laughlin’s theory did not fully explain these. It was Halperin and Haldane who realized that the defects (the quasiparticles) of the nu=1/3 effect can themselves organize, forming further new phases of matter. The resulting picture was a recursive construction of defects condensing then new defects forming within these new condensates.

So why revisit this issue now? Well, the new twist is an entirely new class of more complex and interesting quantum Hall states – the so-called “nonabelian” phases or “nontrivial topological” phases (drawing a distinction that all of the abelian phases are now considered “trivial”). In these cases, the quasiparticles, in addition to carrying charge (and fractional statistics), also carry interesting topological quantum numbers. It is not so obvious how such a thing can form a condensate at all, or whether it would want to do so.

There have been several approaches to addressing this problem. The first set of approaches attempt to condense the nonabelian anyon by forming a topologically trivial combination of quasiparticles and then condensing the combination in the same spirit as the old Halperin-Haldane hierarchy.

(1) An approach by Bonderson and Slingerland combines a pair of quasiparticles on top of each other in a topologically trivial combination then condenses these pairs. A more recent paper by same authors plus Moller and Feiguin shows some nice numerical data showing that these trial states are actually quite competitive for experimental systems – although from the data I saw, it was not completely convincing that there was any regime in which they clearly were better than more conventional trial states. Nonetheless, they seem to be now in the running as something that needs to be seriously considered.

(2) An approach by Levin and Halperin (neither of them happen to be at this conference) is to form a topologically trivial quantum superposition of states before condensing. (Not surprisingly, the resulting states lose all of their topologically interesting properties after the condensation ). There does not appear to be much experimental or numerical evidence of these states being realized, even for model systems.

(3) A third approach by Hermanns is a bit more confusing to describe. At first I thought that it was probably incorrect, but now I think the construction makes a fair amount sense although there are some pieces of the argument that still seem a bit mysterious to me. I’ve agreed to be on Maria Hermanns’ thesis committee, to be her “opponent” in the Swedish system, which I gather means it is my job to find holes in her arguments, so I’ll be studying this a lot more in the next few months.

(4)In the work of Schoutens and Grosberg a condensate naively looks a bit different. In this case, a condensate is made by forming a maximum density droplet of a particular quasiparticle with nontrivial topological quantum number . This case can be analyzed in great detail – determining not only the details of the condensate (which is a known phase) but also the behavior of the edge separating the mother and daughter states. (See below however, the work of (6) seems to be able to phrase this condensation again as a boson condensing).

And there are yet more approaches. In the above approaches, all of the quasiparticles form liquids. There is another possibility which is that all of the quasiparticles form a solid. Solidification would usually be considered uninteresting from a topological perspective, but here since the quasiparticles carry topological quantum numbers something more interesting can happen.

(5) In this picture discussed by Gils, Trebst, and friends Gils, Trebst and Friends, one might have the charge of the quasiparticles pinned in some sort of lattice, but the topological quantum number may still be able to hop around. Although the hopping my be very weak, at very low temperature and long time scale, in principle the topological quantum numbers will settle into a unique “condensed” ground state of their own hopping problem. This is somewhat like electrons forming a Wigner lattice and then looking at the spins on the wigner lattice, which at low temperature, align to form a ferromagnet (or antialign to form an antiferromagnet, which is more typical).
Finally, there is the world of more abstract nonsense:

(6) And a more abstract discussion of condensation was given by Slingerland and Bais. While perhaps a bit daunting at first, this paper is well worth the effort to read. These authors have constructed a generalized paradigm to describe condensation of one topological phase within another topological phase. The general rule is simply that you have to find a particle that is topologically a boson, then you can condense it. Anything that is not “local” with respect to the boson cannot live within the new phase, and you have to identify any two particles that differ from each other by the bosons. (There is a subtlety having to do with particle branching that I will not explain here). Pretty much all of the above cases can be described within this formalism in one way or another. Further, coset TQFTs can be described nicely within this formalism too (which I find very pretty). The down side, as in any abstract nonsense, is the generality is frequently a disadvantage as much as an advantage. Since you can describe pretty much anything, it does not give you hints as to what thing to expect.

At any rate, there are a whole bunch of ways to describe condensation of topological phases within topological phases. Seems like a popular thing to be studying right now. Resistance is futile….

Jumping out of Airplanes

Eddy Ardonne is an avid skydiver. He is currently an assistant professor at NORDITA in Stockholm where I am visiting this month, and he frequently offers to take people skydiving if they so happen to be interested. Smitha Vishveshwara*, who was once Eddy’s officemate, made a jump a few years back and loved it. My colleague from Ireland, Jiri Vala, was absolutely determined to try jumping this week and encouraged me to go too.

Now, to begin with, I’m a guy who doesn’t even like to drive in a convertible because I don’t like that much wind in my face. Why on earth would I want 120 MPH of wind in my face? I’m also rather afraid of heights (yes, I know, I’ve rock climbed in the past, but I never like being near a cliff unless I’m in my harness and anchored in). But perhaps because I was completely terrified of the idea, I was also curious about it, so I started doing some homework to find out, just how dangerous is it?

Being a statistics geek, the first thing I found was that many of the statistics that you find on the web are totally bogus comparisons.

The best verified figure I could find is that in skydiving there is roughly a 1 in 100,000 chance that you will die on any given jump. It might be a bit lower for certain types of jumps, or certain jumpers, and a bit higher for others. But very roughly, this seems always to be the right number**.

But back to bogus statistics: Here’s a statistic that gets thrown around an awful lot:

“Each year about 30 people die skydiving in the United States, and that's out of over 2 million parachute jumps. Given the odds, you're better off skydiving than let’s say driving a car. Every year, over 40,000 people die in traffic accidents”

Similarly many websites state that

“you are more likely to die driving to the dropzone than during your jump”

I’m calling a loud foul on both of these: The fatality rate for driving a car in the US (and most of the western world) is roughly one fatality per 100 million miles driven. So a single jump has the same fatality rate as driving a car one thousand miles. Spending an hour making a single jump is over 100 times more dangerous than driving a car for the same hour. Perhaps it is surprising (even impressive) that jumping out of airplanes is not more dangerous than this, but still the statements being made on the web are clearly inaccurate. I’m not particularly afraid of driving a car for a thousand miles, so there is not really much good reason to be afraid of making a single jump. However, if you make it a habit of jumping out of airplanes, you have to accept that it can start to become a significant added risk.

While I was searching for more statistics on the matter, I found quite a few interesting things about skydiving injuries. One of the strangest facts is that for solo student jumpers (not jumping in a tandem) apparently women have over twice the fatality probability than men. No one seems to know why this is, but it is an established fact. There are some other interesting statistics regarding how many times a fatality occurs from a real splat (no parachute deployment), versus from other means such as mid air collisions, improper landing with proper chute deployment etc. It turns out that the real splats account for less than 30% of the fatalities.

Another interesting stat (which is harder to pin down from data available) is that non-lifethreatening minor injuries are apparently pretty common - the “injury requiring medical attention” rate is roughly 1 out of 1000 jumps. Most of these are minor sprains, breaks, and so forth. But a few are more serious. If you compare this to say, a few years of participating in any other sport, you would probably have a similar rate of minor injuries. (One should be warned however that certain medical insurers do not cover skydiving injuries whether or not they are minor).

Anyway, Jiri and Eddy did go jumping yesterday and they both came back in one piece. I didn’t go. It really came down to a decision of whether I wanted to spend most of a day preparing for a 60 second drop (which I didn’t’ think I would enjoy all that much anyway). I think the main attraction to the idea was just that I was a bit afraid of it.

Maybe when I’m visiting Stockholm next year I’ll think about it again.

*Congratulations to Smitha on her marriage last month.

**It appears that this number does not include the possibility that the small plane you are in crashes before you jump out of it. It is hard to get numbers on the added risk from plane crashes, but my best estimate is that it is unlikely to more than double the risk.

Pripps Blå

Perhaps a better name for it should be BLAH.

Pripps Blå is one of the most popular beers (if not the most popular beer) in Sweden. Blå means “blue” and it is pronounced closer to Blow or Blough. On Wikipedia it is explained that Blå is brewed with 51% barley grain, which is the minimal fraction allowed by law if you want to call yourself a beer. (Not sure what the other 49% is – probably some cheaper grain like corn or rice). Despite the jeers of all of the people around me, I actually like the stuff. It reminds me of similarly terrible American beers like Bud Light and Miller Genuine Draft. It tastes roughly like water, and it comes in big aluminum cans.

So here’s the cool thing about Blå. You can get Blå that is 2.2% alcohol (which you could easily drink for breakfast or lunch and not even notice that it was alcoholic) or you can get the 2.8%, or the 3.5% or the 5.2% or the 7.2% (which is pretty strong). And as far as I can tell, they all taste exactly the same. Nice to have options.

Singing in Swedish

In Swedish, the most common word for “Hello” is “Hej” which is pronounced more or less “Hay”. There is an interesting history to this word posted here about why this greeting was not “the greeting of the masses” until the 1970s. Frequently people repeat it twice: “Hej Hej”. The same website seems to indicate that this implies excitement to see someone (Although the woman at the NORDITA cafeteria seems to use “Hej Hej” for every single customer, and she can’t possibly be excited about every single one).

After a day or two of figuring out that “Hej Hej” is actually a greeting, I started noticing that a lot of people seem to sing it more than say it. Of course not everyone does it the same way, but I’ve heard an awful lot of people who put the second “Hej” almost exactly a major third below the first “Hej”. The Swedish language does have a bit of a sing-song quality to it, but I don’t really detect any other consistent musical intervals in the Language except for when people say hello.

Geek interlude: a major third is a frequency ratio of 5/4=1.25 on a natural scale but is a frequency ratio of the cube root of 2 (1.2599..) on an equally tempered scale.

Speaking of Swedes and music: yes indeed, I have heard a lot of ABBA in Stockholm (Hey, come-on, admit it, you love them too). I was hoping to hear some Ace of Base and the Cardigans too (Yes, they are both Swedish.)