Ancient footprints and modern preprints

"Oh the streets of Rome are filled with rubble,
Ancient footprints are everywhere"

These are the opening lines of Bob Dylan's "When I Paint My Masterpiece and, despite having no masterpieces in progress (and no skill at painting), I was haunted by these words all of last week. The occasion was Strings 2009, the annual String Theory conference, held this year at the "Angelicum" whose very impressive full name is "Pontificia Università San Tommaso d'Aquino".

Saint Thomas Aquinas was a famous theologian of the Dominican order, and this university named after him teaches Canon Law, Sacred Theology and Philosophy, so many will consider it perfectly appropriate that a String Theory conference should be held there! The analogy becomes more amusing if one examines the five precepts of St Thomas, which in brief are:

1. God is simple, without composition of parts.
2. God is perfect, lacking nothing.
3. God is infinite.
4. God is immutable, incapable of change on the levels of essence and character.
5. God is one, without diversification.

If I can permit myself a heresy that will offend both devout Catholics and devout String Theorists: take the above list and replace "God" by "String Theory" everywhere, and you get a charming caricature of what string theorists say about their subject, or at least what other people think string theorists say about their subject.

The surroundings at the Angelicum are beautiful - and the slightly uncomfortable seats are clearly part of the divine plan of making us concentrate on the lectures. But there were more elements to this divine plan that unfolded as the conference progressed.

For those who don't know, a scientific conference in this day and age typically consists of a speaker talking to the backs of several hundred laptops behind which members of the audience check their email, write papers, and occasionally chat with each other via Google Talk. Alas, the wi-fi in the hall simply failed to work. The organisers assured us they had paid for the connection but the $%*#@# (Italian curses) phone company simply wasn't doing their job. On the second day things had not changed one bit. Moreover, this being Rome, most hotels did not offer internet or charged heavily for it (judging from the ads, 6 Euros an hour is considered a "cheap" rate, though it's what most Indians pay for an entire month's internet connection!). I was lucky with my hotel, which had free wi-fi though it was very basic in other ways.

By lunchtime on Tuesday the conference wi-fi finally started working. But unknown to anyone, a new element of the divine plan was unfolding. Just as the afternoon session was getting ready to commence at 2:30 PM, the lights went out. For the next half hour people sat obediently in their seats (the wi-fi of course went away along with the power). Around 3 PM the organisers announced that the power could not be restored that day, so the entire afternoon session was cancelled - or rather postponed to Wednesday, which in the original schedule was to have been a half-day.

I know what you, the reader, are thinking at this point. Clearly the Swiss Guard at the Vatican had started shutting off power selectively to different parts of Rome! I tried to convince my colleagues of this -- but sadly, most had not seen, or read, or even heard of, Angels and Demons. So they looked at me very very strangely.

Anyhow people streamed out of the Angelicum and many went to see the Colosseum which was a short walk away. There, one had the opportunity to stand in a long line (as we had already got used to doing for tea and lunch each day) before entering. Of course once you were inside it was magical, specially if you could succeed in visualising it minus the few thousand tourists. An interesting historical fact about the Colosseum is that half a million humans and a million animals perished within it. Another fact, which I promise I am not making up, is that "Pope Sixtus V (1585–1590) planned to turn the building into a wool factory to provide employment for Rome's prostitutes, though this proposal fell through with his premature death". And a good thing too. How would it have looked if we had all said: "Lectures are cancelled so let's go to the wool factory and look at ex-prostitutes"?

From what I've written so far you may not get the impression that much physics got done, but in fact there were many excellent lectures at Strings 2009. Some of the most impressive ones were about superconductors, QCD, particle scattering and neutron stars. These are important issues for many "earthly" physicists and string theory provides one of the most exciting ways to tackle outstanding problems in these areas. See for example this article. I particularly enjoyed the talks on these subjects by Sean Hartnoll, Ofer Aharony, Juan Maldacena, Nima Arkani-Hamed, Zvi Bern and and Erik Verlinde, the first three of whom had visited my institute in Bombay last year for the Monsoon Workshop on String Theory.

This turn of events is fascinating. Despite the most advertised (and often ridiculed) motivation of String Theory as being a unified theory of all fundamental interactions, the last couple of years have seen an upsurge in its applications to other fields of physics. What's impressive is that the string theorists who work on these applications have taken on a different area of physics and come to know it thoroughly and deeply. For example it's clear that Sean Hartnoll knows superconductivity, conventional and otherwise, extremely well and his presentation was impressive for his simultaneous mastery over that as well as string theory. The same can be said for many others who spoke and yet others who didn't come to Strings 2009.

I begin to feel that if String Theory is like any religion at all, it's not Christianity but Hinduism, which gradually incorporates and ultimately swallows up anything interesting that's going on around it.

I shouldn't fail to mention that there were also many lectures at Strings 2009 on particle phenomenology as related to (or interpreted in) string theory. Clearly the forthcoming experiments at the LHC are on people's minds. I particularly enjoyed Michelangelo Mangano's talk on LHC physics (not relating it to string theory but just updating us on what the likely scenarios are) and found it wonderfully clear, cogent, optimistic and yet balanced.

But back to Rome. As Dylan says, "You can almost think that you're seein' double, On a cold, dark night on the Spanish Stairs". There weren't any cold dark nights, but given that tourists frequently sit on the Spanish Stairs and sing Bob Dylan songs, I can well understand why he was seeing double!

And some people did indeed paint their masterpiece in Rome, many times over. On my last day I got to see the Galleria Borghese, thanks to my dear friend Franco who made the required reservations for both of us. There I discovered (as I've discovered on previous visits to Rome many years ago) what stunning masterpieces had been painted by Caravaggio and Titian, and even more stunning statues sculpted by Gian Lorenzo Bernini. The latter started sculpting as a teenager and had a bunch of masterpieces done before he was 25, which should make the rest of us feel pretty rotten indeed. By the time I came out, my voice was almost as whiny as Uncle Bob's! But I felt deeply elevated and fortunate to have witnessed this sublime level of art.

Now here's a funny thing. The last verse of Dylan's song goes:

"I left Rome and landed in Brussels,
On a plane ride so bumpy that I almost cried."

And the nice coincidence is that I, your humble (ha ha!) blogger, also left Rome and landed in Brussels. But the plane ride wasn't bumpy in the least. Only, my baggage didn't make it.