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Science

Submission + - Stable Negative Temperature System Created (newscientist.com)

slew writes: Scientists at Ludwig Maximilian University of Munich in Germany have created an actual stable system which has an inverted Boltzmann Distribution (aka, Negative Temperature) by using an intermediate bosonic Mott insulator together with a Feshbach resonance in bosonic Potassium with laser cooling.

Although Negative Temperature systems are not uncommon (a pumped laser creates them all the time), they are not usually stable as they are not in thermodynamic equilibrium (in the case of a laser, the high energy state couples to a lower energy state returning the system to a positive temperature realm).

Practical uses are of course far away (they only achieved a billionth of a Kelvin below absolute zero), but studying stable negative temperature systems may help us understand the mechanisms behind dark energy theories.

Science

Submission + - Scientists capture shadow cast by 1 atom (griffith.edu.au)

slew writes: Scientist at Griffith University have shown the first absorption image of a single atom isolated in a vacuum. A single atomic ion was confined in an RF Paul trap and the absorption imaged at near wavelength resolution with a phase Fresnel lens.

They predict this absorbption imaging technique should prove useful in quantum information processing and using the minimum amount of illumination for bio-imaging of light-sensitive samples.

Here's a pointer to the paper...

Science

Submission + - electron's 3rd "quasi-particle (aka "orbiton") observed in insulator lattice (bbc.co.uk)

slew writes: Although electrons are usually thought of having 2 properties: spin and charge, bound electrons actually have a 3rd quantum property related to their so-called orbit's angular momentum. Spinon and holon quasi-particles have been observed before which represent the spin and charge quantum values of the electron. Now this experiment takes advantage of the fact that nominally bound electrons can delocalize in a lattice into energy bands and make it possible to measure the effect of the orbiton quasi-particles (which has the value of the electron's angular momentum where it was originally nominally bound, even though now delocalized). Hope that made some sense...

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