Seth Aubin, associate professor of physics at William & Mary, has been selected as a Fulbright Scholar for the 2014-15 academic year by Fulbright Canada.
As a Fulbright Scholar, Aubin will work at TRIUMF, Canada’s national laboratory for particle and nuclear physics in Vancouver, British Columbia. He will be working with the francium parity non-conservation (FrPNC) experimental collaboration, which is setting up an experiment to observe the violation of parity symmetry in a sample of laser-cooled francium atoms.
Aubin explained that parity symmetry—also known as handedness symmetry—refers to the expectation that a system remains unchanged even if you reverse its spatial properties. Imagine an apple that has been somehow “flipped” into a mirror image of itself. Parity symmetry dictates that if the mirror image of Isaac Newton's apple fell from the tree, it would still be subject to the same gravitational acceleration as the original apple.
In the instance of the mirror-image apple, parity symmetry is completely intuitive, but parity symmetry also applies in more complex circumstances beyond everyday experiences. If you could somehow produce the mirror image of both the apple and the Earth, gravity would still pull the apple toward the center of the Earth, and pull it with the same strength. Parity symmetry is an integral component of gravity, but parity symmetry stops short of being completely universal, Aubin said. An exception rises at the subatomic level.
“Three of the four fundamental forces in the universe obey this intuitive symmetry: the electromagnetic force, gravity and the strong nuclear force,” he said. “Remarkably, the weak nuclear force, which is responsible for radioactive decay, does not obey this symmetry and we don’t understand why.”
Parity violation, the weak force’s exception to the symmetry rules, is a very small effect, Aubin explained. The effect is tiny even when compared to other interactions of particles at the subatomic level. The small effect has big implications for physicists seeking to understand the Standard Model, the inventory of particles and interactions from which the universe is constructed.
Aubin’s group at TRIUMF will work to bring an unprecedented level of accuracy to measuring the effect. The TRIUMF apparatus will use laser cooling to bring francium atoms down to micro-Kelvin temperatures.
“To put it crudely, we basically park a laser cooling apparatus on the end of a particle accelerator,” he explained.
Aubin will bring a wealth of experience to TRIUMF, as his William & Mary research uses laser cooling to chill rubidium and potassium atoms to micro-Kelvin temperatures and even colder, many times colder than the temperature of outer space, to study Bose-Einstein condensates and ultracold quantum gases.
He received a B.S. in physics from Yale University in 1995 and a License de Physique for coursework at the Ecole Normale Superieure in Paris. He obtained his Ph.D. in physics in 2003 from SUNY Stony Brook for research on laser cooling of francium. During 2003-2006, he worked as a post-doctoral fellow at the University of Toronto, conducting research on Bose-Einstein condensates and degenerate Fermi gases. Between his undergraduate and graduate studies, he spent two years in the U.S. Peace Corps as a math and physics teacher in Dalaba, Guinea, West Africa.
Fulbright Canada is a joint, bi-national, treaty-based organization created to encourage mutual understanding between Canada and the United States of America through academic and cultural exchange. Fulbright Canada is supported by the Canadian government through Foreign Affairs, Trade and Development, by the United States Government through the Department of State, and by a diverse group of corporate sponsors, charitable trusts and university partners. It is governed by an independent board of directors and operates out of Ottawa.