(Feb 6, 2024 07:34 PM)Magical Realist Wrote: https://www.scientificamerican.com/artic...icles-rea/
"Are virtual particles really constantly popping in and out of existence? Or are they merely a mathematical bookkeeping device for quantum mechanics?"
Gordon Kane, director of the Michigan Center for Theoretical Physics at the University of Michigan at Ann Arbor, provides this answer.
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"Virtual particles are indeed real particles. Quantum theory predicts that every particle spends some time as a combination of other particles in all possible ways. These predictions are very well understood and tested.
[...] Another very good test some readers may want to look up, which we do not have space to describe here, is the Casimir effect, where forces between metal plates in empty space are modified by the presence of virtual particles.
Thus virtual particles are indeed real and have observable effects that physicists have devised ways of measuring. Their properties and consequences are well established and well understood consequences of quantum mechanics."
The "effects" may be there, but [supposedly] the majority who work with the quantitative and diagram representations "on paper" don't treat the latter as a material fact or the cause.
There's a similar thing going on with other abstract description in QM undertakings. For example, you have anti-realists who do not reify the wavefunction ("shut and calculate" crowd), and conceptual realists who do treat it as concrete or efficacious in one sense or another. (Footnote[1] at bottom for the history.)
Akin to politics, each philosophical side tries to argue and assert its own views as either the authority or a potent challenge to the entrenched perception.
(1) By definition, the adjective "virtual" entails that the putative "particle" is not real. (Whatever the latter itself means, in the contexts of the varying standards of assorted practices and schools of thought).
virtual: "
Being such in essence or effect though not formally recognized or admitted."
(2) All or most parties agree that virtual particles are
at least mathematical artifacts. (
anti-realist: "Anything beyond that is futile speculation and pathetic misapprehension of their purely utile role in perturbation theory." .....
realist: "We have justifications for feeling otherwise.")
(3) All or most parties agree that virtual particles cannot be observed/detected.
(4) Disagreements are philosophy of science issues between rival factions. For the anti-realists, the opposition is misguided and partaking in erroneous myth circulation. Whereas the realists deem themselves as rebelling (or whatever) for enlightened reasons.
Virtual particles do not exist
https://medium.com/einsteins-cup-of-tea/...82de3c1627
EXCERPTS: We often hear the word ‘virtual particle’ in physics and pop-sci explanations of quantum field theory. But, in reality, there are no such things as virtual particles. Today we will explore why (and how) virtual particles are needed, and also why they don’t exist.
[...] Keep in mind that the different oscillations which approximate reality, are just creations of us fiddling around to make our simpler equations fit the problem. These oscillation do not really exist. These are just dummy oscillations, or if you prefer, a mathematical sleight of hand.
Now, we have caught on an habit of calling them virtual particles. We think these particles “come in and out of existence” for “very miniscule periods of time”, or that they are “not real”.
Yes, oscillating fields correspond to particles, but these oscillations (and thus the corresponding particles) don’t exist. They are an invention to simplify a rather complex (and real) oscillation. They do not “exist” at all, even for very short intervals of time.
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Do virtual particles really exist?
https://bigthink.com/starts-with-a-bang/...lly-exist/
EXCERPTS: This doesn’t mean that empty space itself is full of particles, but rather that you have quantum mechanical operators, including the “particle creation” and “particle annihilation” operators, acting on the vacuum state continuously. This is often visualized as “particle-antiparticle pairs popping in and out of existence,” but that part is just a calculational tool for visualizing what’s happening on a quantum level within empty space.
[...] Finally, in 1997 — when Casimir himself was 88 years old — physicist Steve Lamoreaux made the first experimental measurement of the Casimir effect, determining that two closely spaced parallel plates did, in fact, attract due to the differences in the quantum vacuum inside and outside the plates. In multiple different ways, theory and experiment agree.
So the quantum vacuum really does have observational effects, and those effects have been observed experimentally on ~micron scales and astrophysically over stellar scales. That doesn’t mean that virtual particles are physically real, however.
It means that using the calculational tool of virtual particles in the vacuum allows us to make quantitative predictions about how matter and energy behave as they pass through empty space, and how empty space comes to possess different properties when external fields or boundary conditions are applied. The particles, however, are not real, in the sense that we cannot collide or interact with them.
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[1] The following being only a corresponding analogy, between those who choose to reify a useful tool "on paper" and those who don't.
For those who channeled his original lectures and literature, Niels Bohr philosophically dictated either an anti-realist attitude or a Kantian skepticism about the symbol-mediated territory of QM in general (while possibly sparing the observed entities themselves from such critical wrath). Obviously the physics community was not united in paying heed to that over the ensuing decades. So if there is any dissension about ignoring establishment attitude about virtual particles (the resulting muddled confusion), that likewise is hardly surprising.
Niels Bohr: Bohr has often been quoted saying that there is "no quantum world" but only an "abstract quantum physical description". This was not said by Bohr, but rather by Aage Petersen attempting to summarize Bohr's philosophy in a reminiscence after his death.
[...] According to Faye "Bohr thought of the atom as real. Atoms are neither heuristic nor logical constructions." However, according to Faye, he did not believe "that the quantum mechanical formalism was true in the sense that it gave us a literal ('pictorial') rather than a symbolic representation of the quantum world."
[...] Faye notes that Bohr's interpretation makes no reference to a "collapse of the wave function during measurements" (and indeed, he never mentioned this idea). Instead, Bohr "accepted the Born statistical interpretation because he believed that the ψ-function has only a symbolic meaning and does not represent anything real." Since for Bohr, the ψ-function is not a literal pictorial representation of reality, there can be no real collapse of the wavefunction.
Who invented the “Copenhagen Interpretation”? A study in mythology
https://www.jstor.org/stable/10.1086/425941
What is commonly known as the Copenhagen interpretation of quantum mechanics, regarded as representing a unitary Copenhagen point of view, differs significantly from Bohr’s complementarity interpretation, which does not employ wave packet collapse in its account of measurement and does not accord the subjective observer any privileged role in measurement.
It is argued that the Copenhagen interpretation is an invention of the mid‐1950s, for which Heisenberg is chiefly responsible, various other physicists and philosophers, including Bohm, Feyerabend, Hanson, and Popper, having further promoted the invention in the service of their own philosophical agendas.