Honeywell-Nobel Foundation initiative has been doing the wonderful job of taking Nobel laureates to educational institutions and making them address students to inspire them to great great heights in their lives. As a part of that initiative, Dr. Eric Cornell, 2001 Physics Nobel Laureate visited TCE on 23,24 September 2009 and I was privileged to attend his talk on Bose-Einstein condensation which fetched him the Nobel Prize. It was during this session that I was inspired by English and hence the previous post.
Dr. Cornell’s talk wasn’t in Greek and Latin as I had feared it would be, it was far more understandable though I would have been unable to appreciate fully what he explained, only due to my lack of much knowledge in that domain. He was very down-to-earth, very friendly and very funny too. I enjoyed his sense of humour very much. Even for the n00bs who knew very little about the subject, he explained simply and clearly without confusing or overwhelming the listeners. Such a wonderful skill that is.
He then started talking about the Bose-Einstein condensation and the interesting story behind it – http://en.wikipedia.org/wiki/Satyendra_Nath_Bose. It was so inspirational and I felt so proud that an Indian in 1920s had done so much of path-breaking work that even Einstein acknowledged and contributed to! Hats off!
Though Bose-Einstein condensation existed as a theoretical principle, no practical proof/samples were possible to create in about 60-70 odd years. In the 1980s there were some efforts to obtain the Bose-Einstein condensate which continued into the 1990s when Dr. Cornell and his colleague Dr. Karl Wiemann started working in the same direction. They were trying to cool down the atoms to a very low low temperature (in the order of nano kelvin) that the atomic motion will cease and they would form a condensate where each atom becomes indistinguishable and the group of atoms behave as one and exist as a single wave.
They used laser cooling (A technique that won its creators the Nobel prize) to bombard the Rubidium atoms from 6 directions so that they would slow down and stop at some point, where they will just fall down under gravity. As the motion of the atoms cease, the temperature will drop drastically. But if the falling atoms get to touch the container which is at room temperature, they will be boiled to a very high temperature and start moving again which will counteract the cooling. So they applied a concave magnetic field inside which the atoms fall into and stay put. Rubidium was chosen as it has one valence electron and it simplified a lot of things. This laser cooling cooled the gas atoms to a very low temperature but that was still too high for the Bose-Einstein condensation to happen. So they used one more cooling technique called ‘Evaporation cooling’ technique-the oldest known cooling technique known to man.
What they did was to compress and expand the magnetic field periodically so that the atoms with energy started moving and bounced out of the concave field, thereby lowering the temperature of the remaining atoms as atoms with temperature higher than the average temperature bounced out. Simple to hear but difficult to understand and implement.:-). The great man talked about how his colleagues and his students helped him with the experiment and narrated the difficult times they had in the beginning when there were no takers/funds for their work and also the wake-up call they received from competing efforts which propelled them to achieve the goal even faster.
When they achieved the goal of creating a sample of Bose-Einstein condensate, they had a peculiar problem of being unable to capture images with any available equipment. So they used some techniques and somehow were able to film the shadow of the Bose-Einstein condensate. But there was a problem with this setup too that whenever they took snaps, the temperature raise caused from the camera destroyed the condensate and they had to create it again for further work. Wow! Physics was getting biiiiiiiig at the smallest level! I was awestruck and gaped for breath at what I was seeing/listening to. So much of tireless work for a Nobel prize and even more for the advancement of science. Hats off to such people.
For more in-depth and better description and details here are some authoritative links – http://www.physics.otago.ac.nz/research/jackdodd/resources/exp_aspects.html and http://www.colorado.edu/physics/2000/bec/index.html (Colorado University is where this exciting discovery happened and there are explanations from the laureates themselves). Going through these resources is by far better than reading my description of what I thought I had heard and understood. There are a lot of images/diagrams to give a better understanding of the concept and the work that was done.
Then Dr. Cornell talked about superfluidity which is a continuation of his pioneering work about atoms and the vortices, I couldn’t grasp/understand much of it though it sounded interesting despite my ignorance.
The whole talk was videocast over the internet and in the other auditorium where students and staff from other colleges were listening to. He enthusiastically and patiently answered the questions from the audience that were present there and the audience on the internet.
The thing that made this man even more special is that he had his left arm amputated to avoid the spread of flesh-eating bacteria which had affected him. After the amputation and rest, he is back to work as usual and is doing great work and guiding a lot of pioneering work done by his students. The next day he spoke a few words to all the college students who had assembled in the Open-air auditorium to see him. Then he climbed down the stage and wanted to be amidst us, the students and took all their greetings. We all gave him a standing ovation for all his work and his contribution to humanity and Science. I broke down emotionally as I was overwhelmed by such a situation and it’s a great great privilege to have Dr. Cornell at our college and listen to him.
I am so privileged, lucky to have got such a wonderful once-in-a-lifetime opportunity to listen to Nobel Laureate. My grateful thanks to all those who gave me this chance – my college, Honeywell and the great man himself for consenting to visit and give a lecture. Hats off again!
Update: The video of the lecture is now available at http://honeywellscience.com.