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from the (sigh)-still-no-Puerto-Ricoton dept.
amblivious writes:
"Researchers investigating the creation of biexcitons noticed an unexpected drop in energy when creating multiple biexcitons in gallium arsenide, leading to the discovery of a new state of matter; the dropleton. Excitons are quasi-particles created when a photon knocks an electron loose from a material, causing an electron hole. If the forces of other charges nearby keep the electron close enough to the hole a state known as an exciton forms where the combined electron and hole act together as though they are a single particle. Biexcitons consist of two of these quasi-particles and collectively behave like a molecule. In this discovery several excitons are behaving together in a 'quantum fog' and behave like a droplet, hence the name.
See the article in Nature for more information."
(Score: 1) by cosurgi on Tuesday March 04 2014, @08:34AM
Honestly I am not sure if it is rightful to call this a "new state of matter". Maybe, and the reasoning could be following: the equations that can be used to describe exciton are exactly the same that you use to describe a single hydrogen atom in vacuum. The physical difference is that it all happens not in vacuum but in a sea of 10^23 electrons, and the hole's mass (and to be precise, electron's mass also) is a so called "effective mass".
So this is what makes it special: hydrogen atom is the simplest possible system, which has well known solutions. And you can do similar experiments, measurements & predictions on exciton to what you can do with hydrogen atom.
If they somehow manage to create 10^22 dropletons inside a crystal, then I would agree that this is a new state of matter. Because their properties would be very interesting, and maybe bizarre. Especially because they would be allowed to occupy the same energy levels (bosons). It could be similar to something what a high-temperature Bose-Einstein condensate might be if it were allowed to exists in high temperatures. But would be different enough from Bose-Einstein condensate to call it a new state of matter because: 1) high temperature, 2) inside a crystal.
A word about "high temperature". For metals, and electrons flowing there a high temperature is 50000K, but for superconductors high temperature is 50K. For this dropleton state of matter I would expect high temperature to be rather on order of 10K, but that's just a guess.
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(Score: 1) by cosurgi on Tuesday March 04 2014, @03:20PM
actually the more I think about that the more I am inclined to suspect that "high temperature" for dropletons might be around 1000K. But this is the first time I heard about them, so you can see how wild is are my guesses. If it's indeed 1000K, then it could be really interesting to investigate and may yield some useful applications.
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