Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=200303
Story Retrieval Date: 4/17/2015 11:37:26 AM CST
David Nelson and Joanna Carver/MEDILL
A team of physicists, technicians and interns work to get Fermilab's Holometer operational. The stakes are high - the Holometer may prove or disprove that our universe is really two dimensions.
Grand illusion: Are we living in a 2D world?
Imagine that the universe is a hologram, that everything is 2D, not 3D, and that your own vision is a part of a grand illusion. Now imagine a dinky trailer on the prairie and a band of physicists pondering the universe inside, puzzling out a way to prove or disprove whether the world is flat.
“You get a Ph.D. and you work in a trailer,” said Tona Kunz, senior editor of the communications office at Fermilab, “But he loves it.”
“He” is Chris Stoughton, astrophysicist and one of the leaders of quite possibly the quirkiest experiment at Fermilab. Stoughton and a crew of physicists and college students are in the midst of constructing the Holometer, essentially a laser beam that can measure data of gravitational waves at the smallest possible scale. The goal is to determine whether the universe is a hologram.
It’s a test of Fermilab astrophysicist Craig Hogan’s theory, which sprang up when he spoke with a fellow scientist who detected "noise" in gravitational waves that he couldn’t explain. The Fermilab project is mining the same field as string theory, a murky and complex field of physics theorizing how gravity and particles may interact. Stoughton described it as reconciling the very big theory of the universe -general relativity, which relates to gravity - with the very small quantum mechanics.
In what can be called a seminal test of string theory, the Holometer will measure gravitational waves at a scale smaller than any technology of its kind has yet been capable of doing. When looking at waves at such a small scale, quantum mechanics and general relativity no longer apply, making it possible to see whether the universe is flat and everyone’s eyes are playing tricks on them.
"They need to work on it a little more,” Stoughton said, “It’s very complicated. It’s gone through many evolutions. And one of the mysteries for me is how people can stay interested in something for so long that doesn’t necessarily correspond with reality. But thank goodness they do, because they come out at the end with a model that you can do tests on.”
“If it doesn’t work then it doesn’t work,” said intern and recent University of Chicago graduate Ben Brubaker. “And now we know something, and if it does work, don’t take my word for it, but if it does work it’ll change the direction that a lot of theoretical physics is headed.”
There’s a lot that’s odd about the Holometer. For a piece of equipment that will soon be the most sensitive of its kind in the world, it's not exactly receiving the red carpet treatment. Not that Stoughton or anyone else seems to mind. The project is proceeding on a $2 million budget (miniscule by most lab standards) and the laser itself is being built to run in a tunnel abandoned from previous research.
In simplest terms, the Holometer is a laser beam with a set of end mirrors and a beam splitter in this big tunnel, along with something called a photodiode, which converts light into voltage. The project has been in the planning stages for three years, but now the Holometer is at last taking shape and could start operating as soon as this week.
“This model has now predicted something,” Stoughton said. “So the one thing we know for sure that we’re doing here is that Craig Hogan has a theory about what we should see when we set up this apparatus and we’ll either see it or we won’t.”
The answer will be in the gravitational waves that the Holometer should allow them to track.
Stoughton assembled one of the $20,000 end mirrors in a clean room at Fermilab and then installed it on the Holometer dressed in a white body suit and gloves to keep microscopic particles from falling on the mirror and contaminating it.
“The stress level is a little high, but you just gotta do it,” he said.
Whenever he touched anything, he spritzed his hands with alcohol to be sure that even the tiniest particles didn’t fall on it and ruin the experiment.
“When you’ve got a mirror with this kind of sensitivity, just single molecules of stuff laying there or sort of popping off the walls will distort the shape of your mirror,” Brubaker said.
Stoughton said the Holometer could start showing results anywhere from two weeks to two years after it’s up and running.
“I don’t understand the theory behind it,” Brubaker said. “Really only Craig Hogan understands it fully."