Stories
Slash Boxes
Comments

SoylentNews is people

posted by LaminatorX on Monday March 03 2014, @10:00AM   Printer-friendly
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."

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by NovelUserName on Monday March 03 2014, @09:10PM

    by NovelUserName (768) on Monday March 03 2014, @09:10PM (#10233)

    I think what the parent was asking is : "why is this a new class of matter, rather than an interesting subclass of existing matter" The reason for this question is that, to the layman, the exiton sounds like its a special subclass of matter with excited electrons- which aren't new forms of matter. Rather these are energized forms of existing matter. So the question is: why is an exiton special enough that we stop calling it an excitation state, and start calling it a new type of matter.

    I at least have trouble extracting the answer from your post. Is it simply that the exiton is stable compared to the normal means by which electrons change orbitals?

    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 1) by cosurgi on Tuesday March 04 2014, @12:34PM

    by cosurgi (272) on Tuesday March 04 2014, @12:34PM (#10573) Journal

    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.

    --
    #
    #\ @ ? [adom.de] Colonize Mars [kozicki.pl]
    #
    • (Score: 1) by cosurgi on Tuesday March 04 2014, @07:20PM

      by cosurgi (272) on Tuesday March 04 2014, @07:20PM (#10885) Journal

      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.

      --
      #
      #\ @ ? [adom.de] Colonize Mars [kozicki.pl]
      #