COMMENTARY
SPECIALS
INTERVIEWS
CAPITAL BUZZ
REDIFF POLL
DEAR REDIFF
THE STATES
YEH HAI INDIA!
ELECTIONS
ARCHIVES

'It is not all my work... it's a joint collaboration'

For several decades, physicists have struggled to unify two of the most complex and independently successful theories that explain the physical universe-general relativity and quantum mechanics.

Einstein's theory of general relativity is "possibly the most beautiful, most elegant theory ever invented," Dr Ashtekar says, "and the most accurate."

The theory explains things on a cosmic scale -- the sky, cosmic waves, big bang, gravity waves -- very well.

The second theory of quantum mechanics deals with atomic and sub-atomic particles and is "also spectacularly successful," he continues. As esoteric as the theory sounds, we reap its benefits all the time. For instance, the working of solid state devices inside the telephone, computer chips, lasers and nuclear energy are governed by quantum mechanics.

The two theories are conceptually very different. The world of gravitational relativity is precise and geometric, while quantum mechanics is full of chance and uncertainty. This is simply because it is not possible to accurately measure all the qualities of sub-atomic particles.

While there is also uncertainty about the large-scale world defined by gravitational theory, the inaccuracy is so small relative to the size of the object that it becomes irrelevant.

The mathematics used to describe these theories is also very different. "The reason we can maintain this schizophrenic theory of the world is because one refers to the large-scale world while the other refers to small scale," Dr Ashtekar says.

Because the two theories describe the same universe, however, theoretical physicists have long been on a quest to find a grander theory of which both these theories are sub-cases. In specific domains where the two theories meet, gravity is very strong so general relativity is important but there are also phenomena for which quantum mechanics is important. For instance, the universe began with the big bang.

Space, explains Dr Ashtekar, is very curved in the big bang so we cannot use the concept that space is flat. There are also very energetic events in the creation of particles where quantum mechanics become very important. "If you want an answer for what was before the big bang or after the collapse of a star, where it all began and how it all ended, to answer these questions, we need a theory that unifies both theories," he says.

Dr Ashtekar has worked in this field for 25 years and is almost single-handedly credited with one of the most popular unifying theories. Although he initiated the work and is considered the leader, he insists that "it is not all my work. They're all very good people and it's a joint collaboration." In the 1980s, Dr Ashtekar reformulated Einstein's theory of relativity to resemble a modified quantum theory which predicts that at very small scales (10-33 cm or trillionth of a trillionth of a billionth of a centimeter), space is "quantized."

Space looks like a smooth continuum, but since it is a physical entity, it must have physical constituents. Dr Ashtekar and his colleagues are attempting to define what these constituents are, and at which points the continuum picture arises and breaks down. He likens space to a fabric. "Shirts or saris are two-dimensional but at a fundamental level, they are made up of woven one-dimensional threads," he explains. Space, he adds, is similarly made up of one-dimensional quantum "threads."

'He brings a humanness to (science) that's very refreshing' The Ashtekar profile continues.

Tell us what you think of this profile