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Q & A: bosons

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Most recent answer: 10/22/2007
Q:
Can the strength of gravity occur in a range, like the E.M. spectrum? Also, can Bosons interact (or be forced to), even though they can exist in the same quantum state?
- Kevin (age 17)
Jackson I.N.
A:
The gravitational equations (General Relativity) allow waves of all frequencies, just like the E.M. equations. However, gravitational waves have not yet been directly detected. There is evidence from slowing rotations of some dense stars that they do indeed exist just as they ought to according to the theory.

Bosons certainly can and do interact. By an odd coincidence, I was just lecturing on that today. The low temperature properties of He4 (good boson atoms) crudely resemble predictions for non-interacting particles, but show very interesting distinct features that can only come from interactions. There are countless other examples, but I couldn't resist recycling today's lecture.

Mike W.

Actually, all interactions we know about are mediated by bosons. Photons are bosons (they have spin 1) and are exchanged in electromagnetic interactions. The strong nuclear force works by exchanging gluons, which also have spin 1. Protons and neutrons are held together also by the strong force but it is more convenient to think of the particle they exchange as pions, which are collections of quarks, antiquarks, and gluons. Pions have spin zero, and are therefore also bosons. The weak force is exchanged by W and Z particles which are also bosons. Bosons interact with fermions by these interactions. Bosons can also interact with each other. The rate at which photons interact with each other is very very small for low-energy photons. Gluons on the other hand interact with each other quite strongly, as do pions.

Tom

(published on 10/22/2007)

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