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Quantum Camera On a Silicon Chip
stefanparvu14 writes "Physicists in Switzerland and California have developed a new type of camera capable of imaging quantum correlations between pairs of photons. The details are presented in the current issue of the open-access publication New Journal of Physics. Unlike a conventional camera with a CCD imager, this camera is composed of Single Photon Avalanche Diode (SPAD) pixels implemented on a high-performance CMOS chip. One of the authors has provided more background for the non-physicist. Apparently, it could be used to verify the existence of Bose-Einstein condensates that are now starting to be produced in new ways."
The abstract mentions "confirming the presence of true Bose-Einstein macroscopic coherence (BEC) of cavity exciton polaritons." Can somebody elucidate?
A single particle in a confinement, with all the thermal energy removed, is distributed like a wave. That is, you're more likely to find the particle in the middle than at the edges. There's a formula for it (square of a sin, IIRC).
Bosons can all exist in the same state in the same place.
Couple these two facts, and you have a BEC. Basically, put a bunch of bosons in a box, turn the temperature way (way way) down, and you get this neat fuzzy blob of stuff, each particle in (or near) the "ground" (lowest energy) state, denser in the middle than at the edges, that's neither gas nor liquid nor solid. (Nor plasma, for the pedantic.)