Current Winner
2009 NSERC Doctoral Prize

James Day

Physics

University of Alberta

James Day

The colder you make a substance, the more solid it becomes, right? Not always, as it turns out. If the substance is helium that has been cooled to a fraction above absolute zero (-273.15°C) it does not just become a block of frozen helium, but displays unexpected quantum phenomena that scientists believe are evidence of a state of matter they have labeled "supersolid."

News of the initial discovery in 2004 fascinated physicist James Day enough to make it the focus of his doctoral research. His results included important breakthroughs in the highly specialized field of quantum fluids and solids, and earned him a 2009 NSERC Doctoral Prize.

Dr. Day set out to test the supersolid hypothesis, which is based in part on observations that molecules in solid helium also display "superfluid" properties (being able to flow without resistance) at cold enough temperatures. His results helped lend weight to the supersolid interpretation of helium's behaviour. Among other discoveries, he found another unexpected property, namely that the helium suddenly became significantly stiffer at the lowest temperatures.