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Q & A: mass from quantum effects

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Most recent answer: 12/15/2011
Q:
If everything acts as a wave and a particle, and waves have energy, then doesn't wave/particle duality grant everything mass when it operates with mass/energy equivalence?
- Richard Ong (age 14)
Winston-Salem, NC, USA
A:
I think what you're getting at is that things must have "mass" beyond their rest mass. This is certainly true if by mass you mean the (scalar) source of gravitational effects, or the quantity by which velocity must be multiplied to obtain the momentum. Mass in this sense obeys E=mc2, where E is the total energy, including kinetic energy. Since confining any wave to a more-or-less local region requires that it be made up of finite wavelengths, every wave has some non-zero momenta and hence some kinetic energy. So yes, wave effects do contribute something to the mass of even "massless" (no rest-mass) particles. A bag of photons has a bit of weight, though not much.

Mike W.

(published on 12/13/2011)

Follow-Up #1: mass and the Higgs

Q:
If everything is a wave and a particle, then everything has energy (because a wave has energy), and therefore everything has mass. Does this disprove the existence of the Higgs Boson?
- Richard Ong (age 14)
Winston-Salem, NC, USA
A:
No, not at all. Most particles (electrons, protons, ...) have some rest mass, meaning that no matter how smoothly spread out their waves get there's an irreducible floor to their mass. The theorists who understand these things say that in the simplest versions of their standard model for these particles, that rest mass would be zero. They need some sort of background field for the particles to interact with to give them this rest mass. The Higgs field was invented to meet that requirement. It looks likely, based on the latest data from CERN, that the Higgs particle itself will be found with mass in just the range that fits nicely with other sorts of data in which the Higgs is suspected of being involved. If this works out, it will be quite a triumph for the general program of constructing a theoretical framework to describe the particles.

Even if the so-called Standard Model works perfectly in its Higgs prediction, however, things won't be too boring. We know that some 80% of the stuff that clusters in galaxies is "dark matter", which is not described by the Standard Model. Then there's always quantum gravity, which requires some major change in the whole framework. Whether that will help account for the cosmological constant (also outside the Standard Model) via some sort of dark energy remains to be seen.

So stay tuned.

Mike W.


(published on 12/15/2011)

Follow-up on this answer.