A Posteriori

Attempts to grapple with and elucidate empirical knowledge

All the room at the bottom December 8, 2009

Filed under: General Physics — Rāhul @ 18:42
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In December 1959, 50 years ago this month, Richard Feynman gave a talk to the American Physical Society at Caltech. Titled “There’s plenty of room at the bottom”, it laid out the promise of the as yet unborn field we call today nanotechnology, and challenged physicists to turn their attention to unlocking the consequences of the laws of physics at this small scale. The potential of nanotechnology is widely recognised today and significant efforts and funding are directed to it. On this occasion of the 50th anniversary, I would like to review briefly the orignal talk by Professor Feynman and to explore how it has shaped nanotechnology research.

Feynman starts the talk appreciating the unique journey of an experimentalist who makes the first inroads into a hitherto unreachable field like Kamerlingh Onnes in low temperature physics and proposes as a similar area, the “problem of manipulating and controlling things on a small scale”. He then goes on to lay out the interesting challenge of writing the entire 24 volumes of the Encyclopaedia Britannica on a pinhead by reducing all its writing linearly by a factor of 25000 and in the same vein, of having all the information in the great libraries in a small block that can be carried about. Then, he talks about using codes of a few atoms instead of letters and symbols as a way to compress information to even smaller dimensions, which he illustrates as showing the “plenty of room” that is at the bottom. The central advance in technology that Feynman anticipates would drive all this is a better electron microscope. In 1959, electron microscopes could resolve dimensions as low as 1 nm. He challenges physicists to reduce this to 10 pm, an improvement of 100 times, which will help us look at and manipulate individual atoms.

Throughout the lecture, Feynman only described possibilities that follow the laws of Physics as then understood, but were beyond the realm of technology. He focussed on the effects of miniaturisation on computers. In the 50s, Computers with relatively few circuits filled entire rooms. If all the devices and circuits were to be made at the atomic level, he suggested that we could have computers with far more complicated circuits in a smaller space, which is exactly what we have today. Then, he talked of how the problems of lubrication and heat dissipation would scale in a favourable way at small dimensions. He also talked about the possibility of nanorobots entering the blood stream to conduct surgery, an idea that has since received considerable play in Science Fiction. Adressing the problem of assembling at the nano level, he suggested using a cascade of master-slave connections, either mechanical or electrical, that would progressively assemble at smaller and smaller levels and identified the need to improve the precision of the apparatus at each stage. As the final frontier, he considered the problem of re-arranging atoms themselves so as to create from elements and compounds to minerals and virtually anything. He ended by talking about how the physical laws are very different at such a small scale and announcing prizes for a technology challenge in this direction.

Although his groundbreaking work in Quantum Electrodynamics was well behind him, Professor Feynman didn’t then enjoy the public reputation of the supremely brilliant and erudite yet witty and charming scientist that he does today.  So, it is interesting why so many papers in nanotechnology quote this lecture as the beginning of the field. There is no direct link between the talk and the various advances that came later. But in many ways, Feynman has been prophetic. The electron microscope can today resolve down to 50 pm, which is as good as a biologist needs. Computers have indeed packed more and more circuits, devices and memory into shorter areas and grown powerful and complicated. But his vision of nano-level assembly and surgery don’t seem any closer today than when he talked about them.  In a series of articles this month, Nature Nanotechnology points to how a nascent field looked to this lecture as a focal point which drove the enormous advances that we have seen in the last few decades. While Feynman got a lot right through his crystal ball, he also got some which aren’t right yet!

Through the whole talk, the reader (and the listener, I am sure!) can sense the scientific zeitgeist of the 50s,  which was a reductionist viewpoint where everything could finally be analysed by a set of physical laws. Chemistry, Biology and other studies, it was thought, could eventually be reduced to Physics and once we had all the fundamental physical laws, we could build everything else from them. Although this point of view still holds much water and an incessant romantic sway, it is undeniable that the major advances of the last few decades have been in Biology, Psychology and Neuroscience and even many Physicists are today taking an emergent, rather than reductionist, view of the science. It can be argued that this signifies a failure of the vision and intellectual firepower required to make fundamental advancements. Perhaps, we will again return, with a momentous discovery, to the reductionist viewpoint. But for now, Science continues to look where the light is for the needle lost in the dark and tries to push the frontiers of the lighted area ever so much outwards. Maybe it will be the ability to manipulate things on an atomic scale that will eventually lead us  to the next great leap forward!

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