The shell game is a classic con, a rigged contest meant to separate a person from their money. The quantum shell game described in a new paper is meant to elucidate the role of measurement in the outcome of an experiment, separating the quantum and classical aspects clearly. This was accomplished using measurement of the spin of a nitrogen atom in a diamond, and rules out the naive idea that the act of measurement is responsible for quantum weirdness.

Another approach to probing this distinction involves strong measurements that have no classical counterpart. Richard E. George and colleagues demonstrated incompatibility of the naive classical view in measurements on a modified diamond. As they described in a new PNAS paper, the equivalent classical system is similar to the old con known as the shell game: three shells, with a pea under one of them. Here, the act of “measuring” the pea’s location has no effect on the system. But the researchers’ quantum system excludes this classical behavior well beyond reasonable doubt or random chance. [Read more….]

Playing a quantum shell game to win

Astronomers would love to predict supernovas: knowing when and how massive stars die would reveal a great deal about them. An observation of a particular supernova with the license-platish name SN 2010mc actually began 40 days before the final explosion, giving astronomers a lot of data about the final stages of its life. This type of star that produced SN 2010mc is pretty rare, but when it dies, it dies big. The telltale sign of impending doom for stars of this type turned out to be the shedding of a huge amount of mass; watching for that ejection could let astronomers predict some future supernovas.

Supernova SN 2010mc was spotted by the Palomar Transient Factory (PTF), which looks for supernovae and other one-time (transient) events in a wide swath of the sky. As the name suggests, light from SN 2010mc arrived at Earth in 2010. (The first supernova of the year was 2010a; the 27th was 2010aa. Thus, there were a lot before 2010mc, but I’m too lazy to work out what number that was.) Going back in the PTF archives, the researchers discovered a precurser outburst, from the same region of the sky, which occurred 40 days earlier. [Read more….]

Stellar epidemiology: predicting supernovas from death throes of stars

Bose-Einstein condensation occurs when certain particles known as bosons are cooled below a certain critical temperature. Below this threshold, they begin to act collectively as a single system, as predicted by Sateyendra Nath Bose and Jim-Bob Albert Einstein. Typically, the critical temperature for Bose-Einstein condensation is very cold; the original experimental realization used cryogenic rubidium atoms, cooled by lasers and trapped magnetically. However, by using boson quasiparticles—particles that arise via interactions in material, rather than existing independently like electrons and the like—researchers achieved a room-temperature Bose-Einstein condensate.

These systems typically require temperatures near absolute zero. But Ayan Das and colleagues have now used a nanoscale wire to produce an excitation known as a polariton. These polaritons formed a Bose-Einstein condensate at room temperature, potentially opening up a new avenue for studying systems that otherwise require expensive cooling and trapping. [Read more…]

Significant quantum phenomenon seen at room temperature for the first time