What governs the movement of groups of bacteria or fish in the medium in which they live? Physicist Sriram Ramaswamy, winner of the Infosys Prize 2011 is working to understand such organised structures.
Anyone who has seen the popular animation classicThe Lion Kingwould remember the sequence in which the old lion is crushed to death by a horde of rushing wildebeest. What has this got to do with this year's Infosys Prize for the physical sciences?
Sriram Ramaswamy — professor of Physics, Centre for Condensed Matter Theory, Indian Institute of Science (IISc.), Bangalore, and winner of the Infosys Prize 2011 for the physical sciences — who works in an area that is at the crossroads of physics, biology and chemistry, uses this famous simulation to explain the significance of his own work. “Look at a giant fish school,” he says. “A fish in the middle does not know what the fish that is much farther away is doing. It only knows what its neighbour is doing. It is not very different from the physics of stampedes.”
Prof. Ramaswamy (54) is at present working on what governs the movement of small organisms like bacteria or large schools of fish in the medium in which they live. At first glance, a collection of bacteria seen under a microscope appears to move in the same direction. “It looks as if somebody is directing their movement. Actually, what is happening is that each one of them is trying to find food or trying to swim around,” explains Prof. Ramaswamy. “They end up forming organised structures because they are bumping into one another. What are the rules governing the formation of such structures? What do they do when they get disturbed?”
Prof. Ramaswamy's research has been on studying the mechanics of a combined system of particles in a fluid in which the particles are swimming around. An important early influence on his work was the theory of flocking due to a group at IBM and at the University of Oregon. He has also collaborated fruitfully with experimenters at IISc., and at the University of Massachusetts Amherst creating non-living analogues to self-propulsion. “Our group in Bangalore, including colleagues at the Raman Research Institute and the National Centre for Biological Sciences, developed new insights into the problem by combining ideas from the physics of liquid crystals with known ideas in the physics of swimming organisms.” “Interestingly,” he says, “precisely the same equations were developed independently but later by a Paris-Dresden group in a cell biology context.”
Despite his interest in understanding how biological forms behave in the medium in which they exist, Prof. Ramaswamy does not consider himself a biophysicist in the sense in which the term is currently used. “My interest is in the collective properties of matter,” he says. Apart from self-propelled matter, his work with students and colleagues covers dense fluids and how they change to glass; driven colloidal suspensions; powders and grains; how quantum-mechanical systems settle down to equilibrium; and phase transitions in ecology. The number of researchers in India working in the area of the physics-biology interface would be in the tens, according to him. A physicist by training, he says, “This has not been the central enterprise of physics.”
All this is actually quite a simple matter, Prof. Ramaswamy says. “If you had a chunk of living matter, in what way does it differ from something that has the same number of particles in the same pattern, but dead? The dumber the organism, the better our models work. Thinking organisms, which are capable of accumulating information, require more dynamic and complicated models.”
Born in 1957, Prof. Ramaswamy published his first paper in 1978 jointly with a senior graduate student, a year after graduating from the University of Maryland. He says the IISc., which he joined in 1986, has been able to “attract bright talent because it gives you freedom and great students and colleagues”. “This institution is the place, par excellence, where you can do your research. From the day I got here, I have felt this.”
On education system
A passionate advocate of ‘broad-based school education', Prof. Ramaswamy says the Nehruvian era, despite its many great achievements, failed to develop a teacher-cadre system that would have expanded the reach and quality of education (like the administrative services, for instance). “It is great to have high-quality research but I cannot help feeling that we have wasted enormous human resources by not allowing our children a proper school education.” In his opinion, the Kendriya Vidyalaya type of schools ought to be the “minimum acceptable” quality. “Even these are actually for the privileged, mainly Central Government employees,” he notes. Referring to the possibilities offered by e-learning, he says, “It is a pipedream to think that online learning will be able to replace teachers.”
Asked what he proposes to do with the prize money of Rs. 50 lakh, Prof. Ramaswamy says, “Honestly, I never ever thought what I would do if I had so much money.” After a pause, he says, “It certainly feels nice. One of the things I know is that I must not fritter it away.” At the announcement of the prize on Tuesday, a journalist asked him what “applications” would result from his work. Prof. Ramaswamy said, “I have never worked in a mode where application (of my research) was the primary interest, but this entire area attracts researchers because there is the hope that some interesting application will result.”