Abstract:
In 1974 Hawking predicted that black holes were not black but had a quantum instability which caused them to radiate with a thermal spectrum. Unfortunately, for black holes known to exist, that temperature is far to low (tens of micro-Kelvin or lower) to be measured. However, an analogous process was found by me to also take place in fluids flowing so that they developed a sonic horizon (ie, the fluid flows faster than sound or whatever wave one is looking at). This opens the possibility of testing Hawking's prediction in the laboratory. I will report on one such experiment we carried out in Vancouver which showed (via stimulated emission) that surface waves in water in the presense of a surface-wave horizon, would emit with a thermal spectrum, and will also describe some experiments close to practicality where the direct observation of spontaneous emission of this quantum instability is near.
Brief Bio:
Prof. William George Unruh is a Canadian physicist at the University of British Columbia, Vancouver, who described the hypothetical Unruh effect in 1976. He obtained his B.Sc. from the University of Manitoba in 1967, followed by an M.A. (1969) and Ph.D. (1971) from Princeton University, New Jersey, under the direction of John Archibald Wheeler. Unruh has made seminal contributions to our understanding of gravity, black holes, cosmology, and quantum fields in curved spaces. He received Rutherford Memorial Medal (1982), Herzberg Medal (1983), Steacie Prize (1984), BC Science Council Gold Medal (1990), and Fellow of American Physical Society and Royal Society of London (2001).