Natural Order and Science

[Harris]

@Harris

I don't agree with everything Shoshany writes in that quora thread. I think the distinction he makes between virtual and real / actual particles is naive and not as clear - cut as he makes it out to be. The construction and concept of what he calls "actual particles" is no less artificial and no more real that virtual particles imho. He claims that virtual particles are not a thing in nonperturbative calculations. Well, are "actual " particles? If we want theories to be explanations rather than black boxes, we at some point have to take the objects in our calculations and map them to phenomena in nature. Which ones are suitable for that is a subtle question and there may not be a unique correct answer. But to say that actual particles really are real because they appear in this place in the theory, and virtual particles are not because they only appear in this piece of the calculation strikes me as philosophically naive.

He should have said that to what extent objects in theories and calculations "really exist" in nature is a question of philosophy, not physics, and leave it at that. In my explanation I was trying to put a piece of maths into ordinary language. Whether which pieces of maths represent an underlying reality - and what that would even mean - is not something that can just be settled in a quick paragraph.

Concerning your questions: the contradictions you claim do not exist. Demonstrate more clearly why you think they exist.

Quantum fluctuations is not a very precise term referring to statistical uncertainty in quantities that would be sharp in classical physics.

QFT is based on fields as the fundamental objects. Now roughly speaking when you have excitations of those fields, "actual particles" are an idealized object corresponding to a field excitation which satisfies E=mc^2 and lasts forever. Virtual particles correspond to field excitations which do not satisfy these properties. The distinction between the two is kind of fluent.

The connection - Virtual particles are generally subject to quantum uncertainty in their properties, is probably the safest way to say it.

We should not overlook a simple fact:

When particles collide nearly at the speed of light in Large Hadron Collider they burst into clouds full of exotic subatomic particles. All those subatomic particles have physical properties which made them detectable.


However, virtual particles are not detectable by any mean and for that reason in the world of physics they are called “virtual.” They are mathematical objects which scientists have invented for the purpose of calculations of interactions between real particles and it is absolutely inappropriate to treat them as a different category of real physical particles which are detectable.


Furthermore, what you think how much time scientists need to reach some event horizon to study undetectable virtual particles.