Hello!
Sorry for my absence, I have been on my lovely holidays. Thanks to the Slovak-UK connection in the ALICE group, and the experiences of my supervisor and his family, my boyfriend and I decided to take ourselves to the eastern part of Europe for a while, starting in Kosice. We did so much with our time, seeing things that would otherwise be tricky, with great thanks to one of my colleagues, Slavo, who organised visits, bought tickets, taxied us around Slovakia in his car…many thanks indeed!
As a result I have a few very cool experiences to share. The first was a tour of the university and academy of physical sciences in Kosice, renowned for its low temperature physics, so please pardon my pun. Throughout its history, the Low Temperature Physics group has broken boundaries, and in June 2005 they achieved the lowest temperature in central Europe, 50 mK. The lab had an area of wall unpainted and preserved behind glass indicating its first low-temperature achievements, to 1.7 K and so on (the years I cannot recall) and they seemed to find it inspiring to see how far they had come. And it has been a long way – their equipment is very advanced. The lab is unique to Slovakia, something they are proud of but also saddened by – other labs have lost funding, or the heads of group have taken their research elsewhere. They are, like most low temperature physicists, looking at superconductivity, a phenomenon very useful to particle physicists because it means zero resistance, which makes for very easy to maintain powerful magnets, provided you can keep them cold enough! They are exploring many different compounds, investigating their properties and trying to achieve superconductivity at warmer temperatures, which would make our lives even easier! However, the group are also doing some very interesting studies at extremely low (microKelvin) temperatures. There is a lot to learn from superfluid Helium (He4 as a Bose Einstein Condensate, He3 as a fermionic condensate). In this state, the superfluid has zero viscosity, and some very strange behaviour! The properties, (magnetic, electrical, thermal etc) are really quite percquliar, not to mention tricky to measure. Tiny wires on handmade equipment are immersed in the strange substances as probes. This is the kind of science I love!
We also met with the group working on a phenomenon called sonoluminescence, discovered in the 30’s and still poorly understood. This involves creating a bubble in a fluid (apparently it works best with water and air) and applying a standing sound wave causing the bubble to expand and contract in the centre of the beaker. With high enough intensity, the bubble collapses so fast, it produces phenomenal temperatures (albeit very briefly) of the order of tens of thousands of Kelvin, releasing a shock wave of around 10 million photons before expanding again. You can watch the beaker glow a like a tiny blue pixel. If this sounds familiar, it was the phenomenon that was linked to “cold”, or “tabletop” fusion by some scientists in 2002, the idea being that much higher temperatures might be reached, and was claimed to have produced cold fusion in 2006 by the Rensselaer Polytechnic Institute, but is yet to be reproduced (I am saying nothing on that one!). However, it is being used by Pistol shrimp under the sea, who click their claws and create a pressure wave, releasing a bubble from the water that collapses at speed due to the pressure (I think that’s how it works) and knocks the life out of its prey! I have to say, I hadn’t expected my holiday to leave me postulating so much about phase transitions and bubbles and extreme temperatures – it felt like a normal day at work (in a good way)!
There are many more adventures I want to share with you, but I am saving them for another time, so I can get back to work. After all, now that I am back from holidays I find myself with far too many things to do, what with shifts for cosmic ray events starting soon, and LHC collisions due before the year is out!
