Cosmological Constant Problem / Vacuum Catastrophe

[cbd1]

By my understanding, the cosmological constant problem is that the computed vacuum energy by quantum field theory (in the form of virtual particle pairs) is far larger than the measured vacuum energy density.

Would it not seem to solve the problem with dropping the proposed mass of "virtual particles"? Say, we assume that the quantum fluctuations of empty space are just that, artifact fluctuations from the uncertainty principle, and not really particle pairs with mass?

 

[soothsayer]

virtual particles are what are responsible for the fundamental forces in the universe, if they did not have mass, there wouldn't be any transfer of momentum between objects via these virtual particles and forces would not exist.

 

[Vanadium 50]

Soothsayer's answer would imply electromagnetism doesn't work, as photons are massless. Nevertheless, he's right that 'dropping the proposed mass of "virtual particles"' doesn't make any difference in this calculation.

 

[lugita15]

Soothsayer's answer would imply electromagnetism doesn't work, as photons are massless. Nevertheless, he's right that 'dropping the proposed mass of "virtual particles"' doesn't make any difference in this calculation.

Even though the rest mass of a photon is zero, its relativistic mass is nonzero, so it can still transfer momentum.

 

[soothsayer]

Yeah, you have a point there, just because a photon has mass, doesn't mean it carries no momentum. I suppose the same could be said of any massless particle, but cbd1's proposition would also imply that the strong/weak nuclear force are a result of a transfer of massless particles, which must necessarily travel the speed of light, yes? Have any tests been done as to the speed of the nuclear forces? I imagine it would be hard to do, but I do believe the strong and weak nuclear force are suppose to travel slower than c...

 

[soothsayer]

Also, If the virtual particles responsible for nuclear interactions were massless, it would not explain their strength, one would have to conclude that the weak and strong nuclear forces would be as strong as the EMF.

 

[lightarrow]

Even though the rest mass of a photon is zero, its relativistic mass is nonzero, so it can still transfer momentum.

"Rest" mass is not a very appropriate term for a photon or for every particle traveling at c. Simply "mass" is ok.
Anyway, if you want to give it a different name, call it "invariant" mass.
"Relativistic mass" is an obsolete term, you can do without it.
Finally, consider that simply in classical electrodynamics you prove that light has momentum, so you don't need to invoke "relativistic mass" to explain momentum, in this context.

 

[cbd1]

I understand that real virtual particles (if that makes sense) are required for the forces. I see it that this is the only time they actually exist, when they're being used. When they are not used, and it is just empty spacetime, I feel you could find them non-real virtual particles, which no mass, as they do not exist, only when they are actually used are they manifested. I find there could be no proof that this is wrong.. that is, no proof that the virtual particles exist without actually invoking them to participate in doing something real, at which point I would have no argument against their actual, mass-having existence.

Does this jive better?

 

[cbd1]

Soothsayer's answer would imply electromagnetism doesn't work, as photons are massless. Nevertheless, he's right that 'dropping the proposed mass of "virtual particles"' doesn't make any difference in this calculation.

Does this meaning that my understanding of the cosmological constant problem/vacuum catastrophe is wrong? Or was my description generally correct about the problem?

 

[lightarrow]

I understand that real virtual particles (if that makes sense) are required for the forces. I see it that this is the only time they actually exist, when they're being used. When they are not used, and it is just empty spacetime, I feel you could find them non-real virtual particles, which no mass, as they do not exist, only when they are actually used are they manifested. I find there could be no proof that this is wrong.. that is, no proof that the virtual particles exist without actually invoking them to participate in doing something real, at which point I would have no argument against their actual, mass-having existence.

Does this jive better?

Independently of the question if virtual particles "exist" or not, you seem to insist relating their existence to their "mass". The two concepts are unrelated. Real photons, for example, certainly exist, *have energy* and don't have mass.

 

[ZapperZ]

Even though the rest mass of a photon is zero, its relativistic mass is nonzero, so it can still transfer momentum.

This is very vague and inaccurate. A photon cannot have a relativistic mass. Not only is the term no longer accurate (Einstein stopped using it later in the progress of Relativity[1]), but if one were to look at the relativistic mass equation, there's no one for something to have a non-zero relativistic mass with a zero rest mass to start with!

A photon has a momentum. It has no mass, be it relativistic, covariant, or rest. Period.

Zz.

[1] E. Hecht, Am. J. Phys. v.77, p.799 (2009).

 

[cbd1]

Independently of the question if virtual particles "exist" or not, you seem to insist relating their existence to their "mass". The two concepts are unrelated. Real photons, for example, certainly exist, *have energy* and don't have mass.

But it is not virtual photon pairs that are said to be popping into and out of existence. It is thought to be 'virtual particle' pairs, which would be expected to give a large mass equivalence to the vacuum energy. Is it not this mass equivalence value discrepancy where the cosmological constant problem stems?

(And photons do have mass, in the form of their radiation energy equivalent. They just don't have rest mass, but that is not the subject of this thread.)

 

[soothsayer]

So what you're proposing is that virtual particles only have mass if they are being used in creating a force? Seems a little inconsistent to me. If it were true, as to whether or not that decrease in energy would consolidate predicted and measured vacuum energy is beyond me, perhaps it would be an interesting calculation to make, it would certainly imply something very important if the values matched up.

 

[cbd1]

It is clear from the observed cosmological constant that all of the virtual particles in empty spacetime predicted by quantum mechanics simply cannot exist, or the universe would have swallowed itself from gravity from all of these 'virtual' particles. To me, it is simple, for the observations in this universe, the masses of these virtual particles is not real, and thus the virutal particles are not real (as the name "virtual" particles would infer). My answer to this has been that it is not actually particles down there, but only quantum fluctuations as predicted by the uncertainty principle.

 

[soothsayer]

Yes, that's just what virtual particles are, quantum fluctuations, but quantum fluctuations as predicted by the uncertainty principle necessarily have an energy, as allowed by the uncertainty principle, that can't be ignored in gravitational calculations.