Although scientists have described much of the physical universe, they have not agreed on one central theory to explain it all. Associate Professor of Physics Ronen Plesser, a proponent of string theory--the idea that the universe is composed of tiny, vibrating strings operating across 10 dimensions--has been working on this theorized, unified field theory.
The two fundamental theories of modern physics--Einstein's general theory of relativity and quantum mechanics--contain "a theoretical screw-up" and conflict with one another, Plesser explained. "But one expects a physical theory to have universal validity," he said. The purpose of string theory is to unite relativity and quantum mechanics into a single, universal model.
String theory centers around the idea that all matter is composed of strings. These strings are up to a billion, billion, billion times smaller than an atom and vibrate in an unseen, 10-dimensional universe. By wiggling in different ways, the strings become different particles in the three-dimensional universe.
By considering this theoretical model, "It turns out you find an incredibly rich and complex structure," Plesser said. He explained that while humans exist in a 10-dimensional world, they observe only four dimensions--three spatial dimensions plus time--because the other six are "curled up and not noticeable."
Plesser compared the way humans view only four of the 10 dimensions to a large ant crawling along a garden hose. While a smaller ant sees two dimensions as on a plane, the larger ant sees only one dimension along the length of the hose.
Recent research in string theory suggests that the three-dimensional world humans see is really a projection of these higher dimensions, a sort of holographic image, Plesser explained.
Since string theory is entirely theoretical--supported only by its internal consistency and explanatory power--the research at the University is heavily based on abstract mathematics, requiring a collaboration between the math and physics departments. For example, research done by Plesser suggests that radically different shapes in the higher six dimensions give rise to indistinguishable physical shapes in the lower three dimensions, a result that has contributed to long-standing problems in mathematics.
Robert Behringer, chair of the Department of Physics, said that the string theory group is evolving and that the research is one of the physics department's strongest interdisciplinary efforts.
Plesser stressed that rather than concentrating on uses for string theory in technology, it will help humans "understand both math and physics at a higher level," which will inevitably lead to practical applications. He noted that string theory has already aided in the understanding of condensed matter physics.
Although he concedes there is little hope for experimental confirmation of string theory in the near future, Plesser is content with speculation.
"Right now, I'm enjoying looking at the world on a fundamental level," Plesser said.
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