Study unveils new half-light half-matter quantum particles | Hacker News Reader

Study unveils new half-light half-matter quantum particles

phys.org

32 pointslelf6 comments

As usual for wild-eyed headlines like this, it's not quite what it sounds like. This is condensed-matter physics: These aren't "particles" in the usual sense, and they don't exist by themselves in free space. They are more like "particle analogs", which exist as excitations of some underlying matter.

These are "particles" in the same way that we talk about "holes" in semiconductors like they're particles. I.e. "sort of, and for all practical purposes within the relevant domain, but not exactly."

What you say is true, but it should be noted that what we call particles aren't really particles either, and they also don't exist by themselves in free space. A single electron (for example) by itself in free space behaves like a wave, not a particle. What we call particles only behave like particles when they interact with a large system of other "particles" and decohere.

In the context of modern physics a particle, including as referenced in condensed matter physics, refers to all of the quantum wave phenomena that you just described. So to call it a particle in this context is perfectly accurate.

Yes, that's true, but it misses the point, which is that referring to "particle analogs" as "particles" is not at all misleading. In fact, if anything is misleading, it is distinguishing between the two in a way that implies that "particle analogs" are somehow "less real" than "real" particles. "Particle analogs" are "excitations in the state of some underlying matter", but the underlying matter is just excitations in the state of some underlying wave function. The only difference is that the states of particle analogs are more complicated than the states of "real particles" but that is a difference of degree, not of kind.

Just for future reference for everybody involved, these "particle analog" phenomena have a name: quasiparticles.

https://en.wikipedia.org/wiki/Quasiparticle

Here's a link to the abstract:

http://arxiv.org/abs/1406.4826

Here's a link to the paper:

http://arxiv.org/pdf/1406.4826v1.pdf

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