‘Spin’ is a fundamental quality of fundamental particles like the electron, which conjures up images of a small sphere spinning rapidly on its axis like a planet in a reduced solar system.
Only it is not. it cannot. On the one hand, electrons are not spheres of matter but points described by the mathematics of probability.
But California Institute of Technology physics philosopher Charles T. Sebens argues that such a particle-based approach to one of the most precise theories in physics could be fooling us.
By framing the basis of matter primarily in terms of fields, he says, certain quirks and paradoxes that arise from a particle-centric view are vanished.
“Philosophers tend to be attracted to problems that have not been solved for a long time.” He says Sebens.
“In quantum mechanics, we have ways of predicting the results of experiments that work very well for electrons and account for spin, but important fundamental questions remain unanswered: Why do these methods work and what happens inside an atom? ?”.
For the better part of a century, physicists have wrestled with the results of experiments that suggest that the smallest pieces of reality don’t look or behave like objects in our everyday lives.
Spin is one of these qualities. Like a spinning cue ball colliding with the inside wall of a pool table, it carries angular momentum and influences the direction of a moving particle. Unlike the cue ball, however, a particle’s spin can never speed up or slow down, but is always confined to a set value.
To make the basic nature of matter even more difficult to imagine, consider the fact that the size of an electron is so small that it effectively lacks volume. If it were big enough to have volume, the negative charge scattered throughout that space would push on itself, tearing the electron apart.
Significantly, even if we were to be charitable and grant the electron as a particle the largest radius that experiments allowed, its rotation would exceed the speed of light, something that may or may not be a deciding factor on this scale, but for many physicists it is enough to rule out talking about rotating electrons.
One way to make the tapestry of fundamental physics a bit easier to map is to describe points of matter as actions embedded in the fabric of a field, and then interpret these actions as particles.
Quantum field theory (QFT) does this successfully, weaving together aspects of Einstein’s special theory of relativity, classical field theory, and the particle propositions of quantum physics.
It’s not a controversial theory, but there’s still a debate about whether those fields are fundamental, existing even if the flashes through them were muted, or whether the particles are the main players representing vital information and the fields are just a convenient script. .
To us, it may seem like a trivial distinction. But for philosophers like Sebens, the consequences are worth exploring.
as explained in a 2019 article featured in Eon journal: “Sometimes progress in physics requires first going back to reexamine, reinterpret, and revise the theories we already have.”
That reexamination of quantum field theory emphasizes several significant advantages of making fields a priority in physics over a particle-first approach, including a model that reimagines electrons in ways that could give us a better understanding of their behavior.
“In an atom, the electron is often represented as a cloud that shows where the electron can be found, but I think the electron is actually physically spread out on top of that cloud,” Sebens He says.
By being physically distributed throughout a field rather than confined to a point, an electron could rotate in ways that are less of a mathematical construct and more of a physical description.
Although it still wouldn’t look anything like a small planet in a solar system, this spinning electron would at least be moving at a speed that doesn’t defy any laws.
How this diffuse scattering of negatively charged matter resists exploding is a question for which Sebens does not have an answer. But by focusing on aspects of the field of a scattered electron, he feels that any solution would make more sense than the problems that arise from particles of infinite confinement.
There is a quote that has become folklore in the halls of quantum theorists: “Shut up and calculate.“It has become a saying synonymous with the fantasic landscape from the quantum realm, where imagery and metaphor can’t compete with the uncanny precision of pure mathematics.
However, from time to time it is important to pause in our calculations and allow ourselves to challenge some old assumptions, and perhaps even turn around to gain a new perspective on the fundamentals of physics.
This article was published in Synthesis.
