Thu Jan 31, 2013, 11:38 AM
Fire Walk With Me (38,893 posts)
New Order Found in Quantum Electronic Material: May Lead to New Materials, Magnets, Superconductors
Jan. 30, 2013 — Two Rutgers physics professors have proposed an explanation for a new type of order, or symmetry, in an exotic material made with uranium -- a theory that may one day lead to enhanced computer displays and data storage systems and more powerful superconducting magnets for medical imaging and levitating high-speed trains.
Their discovery, published in this week's issue of the journal Nature, has piqued the interest of scientists worldwide. It is one of the rare theory-only papers that this selective publication accepts.
Collaborating with the Rutgers professors was a postdoctoral researcher at Massachusetts Institute of Technology (MIT) who earned her doctorate at Rutgers.
"Scientists have seen this behavior for 25 years, but it has eluded explanation." said Piers Coleman, professor in the Department of Physics and Astronomy in the School of Arts and Sciences. When cooled to 17.5 degrees above absolute zero or lower (a bone-chilling minus 428 degrees Fahrenheit), the flow of electricity through this material changes subtly.
(More at the link.)
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New Order Found in Quantum Electronic Material: May Lead to New Materials, Magnets, Superconductors (Original post)
|Fire Walk With Me||Jan 2013||OP|
Response to Fire Walk With Me (Original post)
Thu Jan 31, 2013, 12:12 PM
DreamGypsy (1,769 posts)
1. Hastatic order in the heavy-fermion compound URu2Si2
Here is the abstract from the January 31, 2013 issue of Nature:
The development of collective long-range order by means of phase transitions occurs by the spontaneous breaking of fundamental symmetries. Magnetism is a consequence of broken time-reversal symmetry, whereas superfluidity results from broken gauge invariance. The broken symmetry that develops below 17.5 kelvin in the heavy-fermion compound URu2Si2 has long eluded such identification. Here we show that the recent observation of Ising quasiparticles in URu2Si2 results from a spinor order parameter that breaks double time-reversal symmetry, mixing states of integer and half-integer spin. Such ‘hastatic’ order hybridizes uranium-atom conduction electrons with Ising 5f2 states to produce Ising quasiparticles; it accounts for the large entropy of condensation and the magnetic anomaly observed in torque magnetometry. Hastatic order predicts a tiny transverse moment in the conduction-electron ‘sea’, a colossal Ising anisotropy in the nonlinear susceptibility anomaly and a resonant, energy-dependent nematicity in the tunnelling density of states.
Evidently the term 'hastatic' was coined by the authors of the article to describe this new type of order.. from the Latin hasta, a spear. This usage does NOT coincide with the Urban Dictionary definition:
1. hastatic 7 up, 5 down