QBism: The simplest interpretation of quantum physics
Adam Frank
Adam Frank
Quote:[*]Quantum mechanics is a powerful yet enigmatic theory that provides exceptional control over atomic and subatomic phenomena, but its underlying mathematical principles lack a universally accepted interpretation.[*]
[*]The theory hinges on the Schrödinger equation and the concept of superposition, where particles exist in multiple states simultaneously until measured, challenging classical physics’ view of reality.
[*]Quantum Bayesianism (QBism) simplifies this by treating the wave function as a personal tool for predicting measurement outcomes rather than a description of objective reality, emphasizing the fundamental role of the Born rule in quantum mechanics.
Quote:So, how does QBism accomplish this so simply? It treats the wave function as encoding information about our interaction with the world, not the world itself as seen from some perfect God’s-eye view. As my colleague, the eminent quantum physicist Joe Eberly, put it, “It’s not the electron’s wave function, it’s yours.” Take this position and you don’t need infinite numbers of unobservable ghost worlds or other science-fiction entities. That certainly seems a lot simpler to me.
The thing about quantum mechanics, however, is every interpretation pays some price that takes you beyond the easy-to-picture-in-your-head perspective of classical physics. QBism’s price is to see quantum mechanics revealing fundamental aspects of us and the world together, not the world alone. The way it pursues this is a relentless focus on the Born rule. Why is there a Born rule? Where does it arise? How does it arise? What is it telling us about us as agents responding to the world as it pushes back against us when we do experiments?
Rather than trying to sidestep the Born rule and see it as a scar, QBism takes it as quantum mechanics’ central and very beautiful mystery. How it does this and what it may mean for science will be the next installment in my QBism series.
'Historically, we may regard materialism as a system of dogma set up to combat orthodox dogma...Accordingly we find that, as ancient orthodoxies disintegrate, materialism more and more gives way to scepticism.'
- Bertrand Russell
- Bertrand Russell