Royal Institution of Great Britain, London
Thursday 15 September 2011, 7.00pm to 8.30pm
Lecturers: Manjit Kumar, Marcus Chown
Introduction by Alok Jar
History of quantum physics
Manjit Kumar galloped through the history of quantum physics at a velocity close to C. But you’ve got to when you’re going to cover that amount of content. Still managing to keep it rich and coherent, the name dropping came thick and fast. Starting out with the favourite physics figurehead, Manjit showed us a picture of a less-than-dapper Albert Einstein stood in front of a blackboard. Hair disheveled, tatty jumper and trousers that looked like they were held up with string. “Look, he just doesn’t care”, Manjit declared, and went on to explain how this was after he and Mileva Marić, his first wife, had split so he had no-one at home to make sure he looks decent.
He went on to expound the contributions of Ernest Rutherford, Niels Bohr, John Stewart Bell, Erwin Schrödinger, Werner Heisenberg and Max Planck (to name a few). I was sad not to hear Paul Dirac mentioned, who shared the 1933 Nobel with Schrödinger, but at this rate, something has got to give.
He touched on the Copenhagen Interpretation of reality which says quantum mechanics describes a reality which only becomes fixed by the action of observation, rather than the classical view that it is already fixed and then we observe it.
The light bulb moment of quantum physics might well be attributed literally to the experiments in black-body radiation to attempt to build better light bulbs. This resulted in the discovery of the discrete quanta of energy described by the equation E=hv. However Planck arranged it, he couldn’t make the numbers work unless h was 6.626068 × 10 -34 now known as Plank’s constant.
Why it’s not scary
Despite having a bit less time due to Manjit’s overrun, Marcus Chown gave a very relaxed, well structured and entertaining talk. Explaining a bit more about the physics without getting heavy in the detail yet still managing to be clear and fun. He did a pretty good job of letting us know we shouldn’t believe the hype. It is possible to understand. In principle at least.
How particle-wave duality expresses itself in the manner you observe: look at your subject as if it was a wave and you will see wave-like results, treat it like a particle and you will see particle-like results. In the crazy world of quantum, they are both till you ask them.
The bombshell came when Marcus explained that although quantum theory explains the quantum world so utterly exquisitely, “we know it’s wrong”. Eh, what? Just when we were getting the hang of it.
Questions
During the questions section afterwards one of the audience asked if “spooky action over a distance” (quantum entanglement) could explain telepathy, both Marcus and Manjit honoured the question with fairly respectable answers, albeit slightly avoiding the nub of the question. Personally, I would have preferred a cox-ism such as “No. You cant explain it because it doesn’t exist” but they are both gentleman and don’t like to provoke the nobbers1.
After hours
Chatting with Marcus after the lecture he told us that Manjit had stolen the punchline of his talk – about how J. J. Thomson had been awarded the Nobel prize for physics in 1906 for showing the atom was a particle, and then his son George Paget Thomson won it in in 1937 for showing it was a wave. How we laughed!
Footnotes
1 Professor Brian Cox is well known for his intolerance of pseudoscience and superstition and has often referred to believers as ‘nobbers’.