Solid, Liquid, Gas... Superglass? Supercomputer helps discover a new phase of quantum matter - a glass that flows faster than water
WATERLOO, ON, June 4 /CNW/ - Does glass flow, creepingly, over the centuries? Despite the uneven, wavy surfaces of mediaeval cathedral windows, the answer is no - glass is a rigid, disordered, solid. But researchers from the University of Waterloo, using large-scale computing at SHARCNET, have found a new way of arranging matter - into a 'glass' that flows with perfect fluidity, and no resistance or viscosity. The individual particles that make up the glass can be part of the solid but also zip around within it with the sort of perfect efficiency only allowed by quantum mechanics.
The team used a combination of supercomputer simulations and pen-and-paper mathematics to examine a system of quantum particles. Expecting to study the interplay between quantum fluctuations and disorder, they were surprised to instead discover that the material they were studying could become freely-flowing "superglass" - and once it entered that phase, there it would remain. No such phase had ever been shown to be stable.
Similar phenomena had been glimpsed earlier by groups studying solid Helium; but in those experiments, superglassiness was a fleeting effect. The Waterloo team has shown that superglass can also be a stable phase of matter, realized if only a few common ingredients, such as disorder and quantum fluctuations, are combined in just the correct proportions.
The breakthrough that allowed the work to proceed was the availability of massive computing resources. "This work would not have been possible even 5 years ago," said Roger Melko, who oversaw an enormous set of simulations over the course of several months that mapped out the superglass phase. "Classical glass simulations are some of the most CPU intensive calculations on the planet. Add in the additional ingredient of quantum fluctuations, and you are asking a lot from a computer. SHARCNET's large cluster of 3000 processors was instrumental in obtaining these results."
The discovery could lead to new insights in the formation of quantum solids. "It is exciting to be at the forefront of research in this field," says Melko. "The condensed-matter physics community is truly probing new elemental phases of matter, something that hasn't been done in decades. A new science is emerging: we can now do computational experiments to discover new quantum effects. Conferences like HPCS, acting both as a way to communicate research results and as a venue to share computational techniques, are important in keeping Canada on the forefront of this scientific revolution."
More information at http://hpcs.ca/press/superglass.
SHARCNET was established in 2001. It is one of seven world-leading Compute Canada (http://www.computecanada.org) supercomputing consortia. SHARCNET currently serves 14 universities, 2 colleges, and one research institute across western Ontario. For more information, please visit http://www.sharcnet.ca.
The High Performance Computing Symposium is Canada's foremost research supercomputing conference. The 24th HPCS takes place at the University of Toronto on June 5-9. More information is available at http://www.hpcs.ca.For further information: http://hpcs.ca/press/superglass