Theoretical physicist Michael Duff is trying to change the shape of the universe or at least the shape of the stuff it is made of.
If theories proposed over the past year by Duff and his colleagues in Texas A&M University’s Center for Theoretical Physics hold up, particles that are the building blocks of the universe may change from infinitely tiny points to bubbles and sheets and tubes.
And the mathematical equations that physicists use to describe them could become part of an allencompassing “theory of everything.”
“Such a theory would mean that at the fundamental level, we would know, in principle, all there is to know,” says Duff, a distinguished professor in Texas A&M’s Department of Physics. “Of course, that doesn’t mean we would understand biology or sociology or whatever. But at the most fundamental level there would be essentially nothing new to say.”
The work done by Duff and his colleagues, Texas A&M Ph.D. physics students Joachim Rahmfeld and Ruben Minasian, won’t actually change the shape of these fundamental particles, of course. But it could transform the way physicists understand and describe them mathematically.
Conventional physics theory says that at its most basic, the universe consists of infinitely tiny particles. Physicists describe them mathematically as “dimensionless pointlike objects.”
This idea has recently come under attack. Duff says one of the most important advances in the theory of fundamental particles came in the mid1980s, when theoretical physicists (including several at Texas A&M) began to explore the idea that fundamental particles might be described more accurately as “onedimensional” objects strings.
Together with supersymmetry an idea physicists use to look at what appear to be different kinds of particles as if they are different “views” of the same particle strings opened the way for the advances proposed by Duff and his fellow theoreticians.
Duff and a growing group of likeminded scientists, however, say, when put together with the ideas of strings and supersymmetry, new calculations suggest the shapes of these particles may be more accurately described as membranes bubbles and sheets and tubes.
In fact, calculations by Duff and his colleagues at Texas A&M also suggest the particles exist in 11 dimensions rather than the conventional four (length, width, height and time) in which we usually visualize the world. The additional dimensions are “compactified” so only the four dimensions we are familiar with are visible.
These new shapes and additional dimensions are the latest steps in a decadeslong quest for a “theory of everything” a single mathematical equation or set of related equations that describe the structure and operation of the universe.
The difference between invisible dimensionless pointlike objects and equally invisible 11dimensional bubbles and sheets and tubes may seem rather pointless to nonphysicists. To the researchers who study them, however, the difference is crucial because it changes the way the particles can behave.
“If you can regard what are apparently different particles, and apparently different forces, as really being different aspects of one kind of force or one kind of particle, then that’s progress as far as we’re concerned,” Duff says.
The growing acceptance by physicists of the 11dimensional particle world proposed by Duff and his colleagues marks a substantial shift in thinking among leading theoreticians. “One Nobel Prize winner once said, ‘Eleven dimensions ugh!’ and covered his ears when the idea came up during a theoretical symposium,” Duff says. “He was sold on 10 dimensions, by the way.”
That attitude seems to be changing. Duff and Minasian have recently collaborated with renowned theoretical physicist Edward Witten of Princeton University to write an article that vindicates many of Duff’s ideas. Witten used to be critical of the 11dimension theory but is now its leading advocate.
Physicists say the idea of 11dimensional membranes is probably the most exciting theoretical development since researchers began in the mid-1980s to investigate the idea that fundamental particles might be something other than pointlike objects.
The work by Duff and his colleagues has been described in articles in the journals “Physics Letters” and “Nuclear Physics”.
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