Reality: in quantum mechanics, fields are real (General)

by David Turell , Saturday, February 18, 2023, 18:49 (425 days ago) @ David Turell

So-called particles exist in real energy carrying fields:

https://bigthink.com/starts-with-a-bang/quantum-fields-energy/?utm_campaign=swab&ut...

"One of the biggest questions that appears right at the intersection of physics and philosophy is as simple as it is puzzling: what is real? Is reality simply described by the particles that exist, atop a background of spacetime described by General Relativity? Is it fundamentally wrong to describe these entities as particles, and must we consider them as some sort of hybrid wave/particle/probability function: a more complete description of each “quantum” in our reality? Or are there fields, fundamentally, that underpin all of existence, where the “quanta” that we typically interact with are simply examples of excitations of those fields?

"When quantum mechanics arrived on the scene, it brought with it the realization that quantities that were previously thought to be well-defined, like:

"...the position and momentum of a particle, its energy and location in time,and its angular momentum in each of the three spatial dimensions that we have, could no longer be assigned values, only a probability distribution for what values they could take on. Although this weirdness, on its own, brought about many arguments over the nature of reality, things would soon get even weirder with the introduction of quantum fields. For generations, physicists argued whether those quantum fields were actually real, or whether they were simply calculational tools.

"Nearly a full century later, we’re certain that they’re real for one unambiguous reason: they carry energy. Here’s how we found out.

***

"Classically, you’d describe the fields (like electric and magnetic fields) that each particle generates, and then each quantum would interact with those fields. But what do you do when each field-generating particle has inherently uncertain properties to it, like position and momentum? You can’t simply treat the electric field generated by this wave-like, spread-out electron as coming from a single point, and obeying the classical laws of Maxwell’s equations.

"This was what compelled us to advance from simple quantum mechanics to quantum field theory, which didn’t just promote certain physical properties to being quantum operators, but promoted the fields themselves to being quantum operators.

***

"Of course, one could argue that quantum fields needed to be real from the very start: since the first observation of the Lamb shift back in 1947. Electrons in the 2s orbital of hydrogen occupy a very slightly different energy level than electrons in the 2p orbital, which did not arise even in relativistic quantum mechanics; the Lamb-Retherford experiment revealed it even before the first modern quantum field theory — quantum electrodynamics — was developed by Schwinger, Feynman, Tomonaga and others.

"Still, there’s something quite special about predicting an effect before it’s observed, rather than explaining an already-observed effect after the fact, which is why the other three phenomena stand apart from the initial impetus for formulating a quantum field theory.

"One possible connection to the larger Universe is the fact that the observed effect of dark energy, which causes the accelerated expansion of the Universe, behaves identically to what we would expect if there were a small but positive, non-zero value to the zero-point energy of empty space. As of 2023, this is still speculation, as calculating the zero-point energy of space is beyond the present capability of physicists. Nevertheless, quantum fields must be considered real, as they carry energy and have both calculable and measurable effects on the light and matter within the Universe. Perhaps, if nature is kind, we might be on the cusp of discovering an even deeper connection."

Comment: quantum reality is more 'real'. Particles are still smudges in their fields. but the fields really exist and can be dealt with mathematically.