Reality: in quantum mechanics (General)

by David Turell , Tuesday, January 10, 2023, 02:57 (682 days ago) @ David Turell

A new look:

https://bigthink.com/starts-with-a-bang/quantum-reality/?utm_source=mailchimp&utm_m...

"Despite what we might have intuited beforehand, the Universe showed us that the rules it obeys are bizarre, but consistent. The rules are just profoundly and fundamentally different from anything we’d ever seen before.

"It wasn’t so surprising that the Universe was made of indivisible, fundamental units: quanta, like quarks, electrons, or photons. What was surprising is that these individual quanta didn’t behave like Newton’s particles: with well-defined positions, momenta, and angular momenta. Instead, these quanta behaved like waves — where you could compute probability distributions for their outcomes — but making a measurement would only ever give you one specific answer, and you can never predict which answer you’ll get for an individual measurement.

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"In other words, every individual electron has a finite probability of having its spin be either +½ or -½, and that making a measurement in one particular direction (x, y, or z) determines the electron’s angular momentum properties in that one dimension while simultaneously destroying any information about the other two directions.

"This might sound counterintuitive, but it’s not only a property inherent to the quantum Universe, it’s also a property shared by any physical theory that obeys a specific mathematical structure: non-commutativity. (I.e., a * b ≠ b * a.) The three directions of angular momentum don’t commute with one another. Energy and time don’t commute, leading to inherent uncertainties in the masses of short-lived particles. And position and momentum don’t commute either, meaning you cannot measure both where a particle is and how fast it’s moving simultaneously to arbitrary accuracy.

"But pinning down the behavior of nature under all sorts of circumstances is very different than assuming there even is some sort of objective reality that exists, deterministically, independent of any observer or key interaction.

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"The idea that there is a fundamental, objective, observer-independent reality is an assumption with no evidence behind it, just thousands upon thousands of years of our intuition telling us “It should be so.”

"But science does not exist to show that reality conforms to our biases and prejudices and opinions; it seeks to uncover the nature of reality irrespective of our biases. If we really want to understand quantum mechanics, the goal should be more about letting go of our biases and embracing, without additional assumptions, what the Universe tells us about itself.

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"In science, it is not up to us to declare what reality is and then contort our observations and measurements to conform to our assumptions. Instead, the theories and models that enable us to predict what we’ll observe and/or measure to the greatest accuracy, with the greatest predictive power, and zero unnecessary assumptions, are the ones that survive. It’s not a problem for physics that reality looks puzzling and bizarre; it’s only a problem if you demand that the Universe deliver something beyond what reality provides.

"There is a strange and wonderful reality out there, but until we devise an experiment that teaches us more than we presently know, it’s better to embrace reality as we can measure it than to impose an additional structure driven by our own biases. Until we do that, we’re superficially philosophizing about a matter where scientific intervention is required. Until we devise that key experiment, we’ll all remain in the dark."

Comment: throw out all preconceived thinking. It is counterintuitively wrong. Live with it.