Celtic Connections

Celtic Connections is Glasgow's annual, winter festival of "roots music", Scottish and Celtic certainly but also genres like Country and Western that have some kinship, and indigenous musics from across the globe. Most music that still retains some element of "authenticity", according to some criterion or other, can turn up there. I don't enjoy only "clattery, atonal music" so there are always many more appealing gigs than I have time or money for.

My wife and I looked through the 2017 programme together. It's always a pleasure to find musical common ground. Both of us laughed out loud, involuntarily when we saw Olivia Newton-John's name among the headliners. Ms Newton-John started in country music, she's had a huge, starry career in popular music, she'll sell out at Celtic Connections and her audience will be ecstatic. So why did we laugh? Perhaps even the organisers expected some people to laugh when they wrote: "It might seem a startlingly long way from Sandy in Grease to Celtic Connections." Or perhaps the alternative version, "Olivia Neutron-Bomb", hybrid of 1980s headlines, popped up unbidden in both our minds. Pesky neutrons, there's so much to say about them, even before thinking of Ronald Reagan and the French nuclear weapons programme.

Amusement passed and attention moved on. I blogged about the famous photo of the 1927 Solvay Conference. I did not expect Olivia to pop up again so soon but she did. My mind is still slightly blown by the discovery that she is the granddaughter of Max Born, one of the founders of quantum mechanics. Love song pop music bumps up randomly against the fundamental nature of reality.

Here's the Solvay Conference picture again. Born is second from right in the second row, with Niels Bohr on his left-hand side at the end of the row. The Scot CTR Wilson is just to his left in the front row.

Born recognised that matrix algebra lay at the heart of Heisenberg's weird new view of inside the atom. Born was the man who saw how to use the wave in Schrödinger's wave equation to calculate the probability of finding the particle. No more little billiard ball particles ever again, but an elusive cloud of possibility. His contributions were recognised in the 1954 Nobel Prize for Physics.

I've been scouring - well, glancing at - Olivia Newton-John's discography. Can we find traces of fundamental physics? I'm afraid I struggled. Those country songs about home towns and true love, Banks of the Ohio, Take Me Home Country Roads, If You Love Me Met Me Know, there's not much traction there. But here she is singing, Let Me Be There: an impossible request. When the listener carries out that experiment that reveals exactly where Olivia is, there is no way of telling where she will be found. There is a most likely position, and a region around that where she has, say, a 90% chance of being found but we can never say exactly where she will be. "Let me be there" is a plea that might be satisfied, by chance, but there is no agency that can see to it for her; no hidden variables that can be manipulated to her advantage.

"This is nonsense," you say. "If Olivia wants to be in Ohio, or Carradale, or in her lover's arms, of course she either will or won't be." In practical terms this is true. Quantum effects play no role in predicting positions on the scale of everyday life. But if Planck's constant were bigger, we would have to think about these possibilities and they are an essential part of understanding the subatomic world.

I doubt I'll be be there myself - sorry, too far from my musical comfort zone - and I don't expect any of this will trouble very many others in Olivia Newton-John's Celtic Connections audience. But really, if she sings Let me be there, feel free to ask her what her grandfather would think.

From Bern to Solvay

I spent last week at the International Space Science Institute (ISSI), Bern, Switzerland. I was there with a team of scientists aiming to understand better the role of energetic ions in solar flares.

Our team went really well, excellent discussions, progress on our key questions, but by Friday afternoon everybody else had left. I worked for a little bit on the team website before skiving off to become a tourist for a few hours. (Complete aside: let me mention how surprised I was by the etymology of skive. As one of those few thousand words we all had in common in school, and a very important one, I always assumed it was a Scots word; not according to the Oxford English Dictionary).

Albert Einstein lived in Bern for a few years at the very start of the 20th century, famously working as a patent clerk at the same time as puzzling over questions like, "how would the world look to somebody travelling with a beam of light?" A scientific paper he wrote in 1905 earned him the Nobel Prize in Physics and it probably isn't even the most important paper he published that year. The time he spent in Bern represents an extremely important episode in the history of science and it's no surprise that the apartment he lived in is now a tiny museum, the Einsteinhaus.

On Friday afternoon I visited the Einsteinhaus. There are nice displays on his family life, his career, his fame. Among them my eye was caught by a mounted print of the photo at left, showing attendees at the 1927 Solvay conference. It's a very famous photo, showing many of the biggest names in 20th century physics all together at the same meeting. Like most physicists I've seen it often, in various places, and noted for example CTR Wilson, our great Scottish genius of experimental physics, second from right at the front.

In the Einsteinhaus I took some minutes to look again at this picture. It's amusing to see the faces that go with those famous names. Who looks confident, bold, who shy and diffident? At the far left-hand side I was slightly surprised to spot two gentlemen almost side by side whose names are often met together in the textbooks, Messrs Peter Debye and Irving Langmuir. Langmuir is right at the left end of the front row, with a rather natty cane. The moustachioed Debye is peering over Langmuir's right shoulder.

In very hot gases, like those met in the outer layers of the Sun, collisions between atoms are sufficiently violent that they completely remove electrons; ionise the atoms. The constituents of the gas are electrically charged. We call the gas a plasma - a term first used by Langmuir, apparently. Plasma behaves in all sorts of new and interesting ways compared to the ordinary, neutral gas we're surrounded by here at sea level on Earth.

The Debye length is the greatest distance over which an electric field can persist in a plasma - because its constituents are electrically charged, if we try to impose an electric field the charges will just move to short it out. Langmuir waves are something like sound waves but with electric fields playing a central role. Their natural frequency, the plasma frequency, is one of the basic numbers that describe a plasma. The Debye length is another. In the first few pages of any book on plasma physics we meet the names of Langmuir and Debye so it tickled me to find the two of them side by side in the 1927 Solvay Conference picture.

Both were Nobel Prize winners, for Chemistry rather than Physics. Langmuir later became rather notorious for attempts at rain-making. The great German scientist Arnold Sommerfeld was once asked what was his greatest discovery. "Debye," he replied.