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Laser Creates Quantum Whirlpool

Posted by Soulskill on from the don't-fall-in dept.

Quantus347 writes: Physicists at The Australian National Univ. (ANU) have engineered a spiral laser beam and used it to create a whirlpool of hybrid light-matter particles called polaritons. Polaritons are hybrid particles that have properties of both matter and light. The ability to control polariton flows in this way could aid the development of completely novel technology to link conventional electronics with new laser- and fiber-based technologies. Polaritons form in semiconductors when laser light interacts with electrons and holes (positively charged vacancies) so strongly that it is no longer possible to distinguish light from matter.

7 of 59 comments (clear)

  1. What, no Lightsaber jokes? by Marxist+Hacker+42 · · Score: 3, Funny

    Did I get first post?

    Still, something tells me this is only a quantum effect, not macro

    --
    SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
  2. I thought the distinction was arbitrary already by i+kan+reed · · Score: 3, Interesting

    Polaritons form in semiconductors when laser light interacts with electrons and holes (positively charged vacancies) so strongly that it is no longer possible to distinguish light from matter.

    I thought the distinctions made already are already mostly ones of convenience and scale: matter is slow and heavy enough to mostly be possible to model as point masses, while light is fast, light, and numerous enough to be more convenient to treat as non-discrete energy than as individual photons.

    1. Re:I thought the distinction was arbitrary already by students · · Score: 5, Informative

      Matter has mass. Light has no mass. That's a pretty significant distinction. A polariton's mass can change continuously as a function of energy from zero to about twice the electron mass.

      The summary is a little odd. A hole is not a charged vacancy. A vacancy typically refers to a fixed (at low temperatures) location where an atom is missing in the lattice of a crystal. A hole is a mobile positive charge with mass similar to the electron mass.

      (Recently finished my PhD studying polaritons and vacancies.)

      --
      Simon's Rock College
    2. Re:I thought the distinction was arbitrary already by Lord+Crc · · Score: 4, Informative

      The one scientists use today: invariant mass aka rest mass.

      http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html

    3. Re:I thought the distinction was arbitrary already by Khashishi · · Score: 2

      Matter has mass, but not all that has mass is matter. There are several types of polaritons, and some of them are clearly not matter, even though they have mass. Phonon-electromagnetic wave quanta are clearly not matter. Moreover, you state that light has no mass, which normally I wouldn't disagree with, but in the context of polaritons, what about light propagating through nonlinear media? I think it's totally appropriate to say it is massive.

    4. Re:I thought the distinction was arbitrary already by students · · Score: 3, Informative

      The rest mass is the right mass to talk about in nearly all situations, rather than the relativistic mass.

      --
      Simon's Rock College
  3. Re: I thought the distinction was arbitrary alread by sexconker · · Score: 2

    It's i kan reed.
    Just skip over it.