|MadSci Network: Physics|
In physics, a critical point is the point where transitions take place. For instance, the temperature at which ice melts into water is a critical point, and the temperature that water boils into steam is another critical point. The event horizon around a black hole is another example of a critical point. A quantum critical point is a critical point on a quantum scale. They aren't driven by temperature (like ice to water to steam) or by gravity (like an event horizon), but quantum fluxuations. Some metals take on unexpected properties when quantum critical points are reached. I don't know the specific changes that take place - this really isn't my area of study. So let's turn to the expert. Qimiao Si, who is mentioned in the article you read, wrote a paper in October 2001 that explains in more detail what quantum critical points are and how metals behave when undergoing quantum changes, and how the experiments he and his team did could explain the latest theories in quantum mechanics. Access to the paper is unfortunately restricted unless one happens to be a subscriber to Nature, but a brief excerpt from it can be read here - fhttp://www.nature.com/cgi-taf/DynaPage.taf Thanks for the question, Layne Johnson
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