Physicist Seeks Universe’s Dimension

By David Wahlberg, The Wisconsin State Journal

Dec. 23–The white walls of Gary Shiu ‘s office are broken up by little but a blackboard and a calendar. But inside the plain space, the soft-spoken UW-Madison physicist is creating dramatic images of phenomena people can ‘t see.

He ‘s trying to figure out the shape of the universe ‘s alternate dimensions.

Shiu specializes in string theory, a yet to be proven concept that scientists hope will reconcile Einstein ‘s theory of relativity with the incompatible law of quantum mechanics.

He is mining two forms of data that could help prove the theory: cosmic energy from the Big Bang and high-energy particle collisions.

String theory, proposed in the 1970s and formalized in 1984, says matter is composed not of tiny particles, as scientists had long assumed, but of tiny, vibrating strings.

Shiu

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According to the theory, certain vibrations of the strings explain large-scale forces such as gravity, now governed by relativity. Other vibrations explain atoms and other small particles, now covered by quantum mechanics.

If proven, string theory could become the “theory of everything ” that eluded Einstein and has since kept legions of scientists up late at night.

The mathematics of string theory requires the existence of 10 dimensions — six more than the four humans observe (the three dimensions of space and one of time). The extra dimensions are thought to be curled into tiny geometric shapes at each point in the universe.

Shiu is trying to define their shapes.

In a paper published in February in Physical Review Letters, he studied cosmic energy released by the birth of the universe 13 billion years ago. The energy, which persists today, has been captured by satellites. Temperature fluctuations in the energy can be traced back to different shapes of dimensions in the early universe, Shiu and his colleagues showed.

“It ‘s like anthropologists looking at fossils and trying to learn something about what went on in the past, ” he said.

In an upcoming paper, Shiu and his colleagues outline how scientists also can use high-energy collisions to “hear ” resonances from particles called gravitons to figure out the shapes of the other dimensions.

“It ‘s like trying to reconstruct the shape of a drum by hearing the musical notes it generates, ” he said.

Such collisions will be carried out in a capacity never seen before at the Large Hadron Collider, to open next year in Switzerland.

UW-Madison ‘s Wesley Smith is one of thousands of physicists who will work at the massive collider. For one of the main experiments, he ‘s in charge of selecting which tiny fraction of the billions and billions of bits of data should be kept and analyzed.

“It ‘s a significant responsibility, ” Smith said. “But from the theoretical work Gary and others have done, we believe we know the signs to look for. “

Shiu, a native of Hong Kong, was in graduate school at Cornell University in the mid-1990s when scientists showed that several versions of string theory were alike.

The finding generated significant excitement, and Shiu plunged into the pursuit. In 2002, he joined the UW-Madison faculty as part of a “cluster hire ” that included two other string theorists: Albrecht Klemm and Akikazu Hashimoto.

Shiu ‘s inspiration to study physics came in high school when he read Einstein ‘s “The Meaning of Relativity. ” He was struck by the childlike but profound questions Einstein posed while testing his theories.

While Shiu ‘s string theory research may seem removed from everyday life, he finds that many people are interested in what he does.

Some cab drivers in Madison, after learning of the focus of his research, have pulled over to discuss string theory with him. “This is a surprisingly educated town, ” he said.

The awareness may stem in part from Brian Greene, a best-selling author and frequent guest on TV science shows who has popularized string theory. Greene gave a well-attended lecture at UW-Madison two years ago. Shiu has collaborated with Greene on some projects.

When Shiu isn ‘t studying or teaching string theory, he can often be found reading mysteries, including those by Dan Brown.

“I like stories that don ‘t unfold until the end, ” he said. “It ‘s just like science. You don ‘t know what you ‘ve got until the end. “

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