Link: https://www.quantamagazine.org/where-does-the-quantum-world-end-and-ours-begin-20260917/

Jonathan Halliwell explains how quantum decoherence is key to understanding how we transition from a world with a wave-like nature of matter and energy to the classical macroscopic world that we’re used to.

Quanta magazine posts endless bullshit like this which never says anything.

The answer is "emergence". Or "somewhere around the size of a few atoms".

Spoiler: our world and the quantum world are the same place.

Exactly.

The "transition" (for lack of a better term) occurs as gamma increases.

IIRC gamma is the value (constant?) that describes the "curvature" of spacetime. Another way I've heard it described is it's the value that describes the relationship between space and time.

The reason we don't see relativistic effects at macroscopic scale is because gamma is effectively 1 at these velocities - it's like the curvature of space time has a trivial effect in the calcation.

I'm probably screwing this up all sorts of ways, it's been years since I've done deep reading, so any and all clarifications/corrections are requested.

We do see relativistic and quantum effects at macro scales. Not necessarily day to day, but many experiments have shown it's quite a blurry line between quantum states and 'normal' states.

From things like Bose-Einstein condensates having quantum properties across the entire mass, and experiments showing that electrons and even things as big as protons still can exhibit wave-like properties, amongst many other phenomenon, it's blatantly obvious there is no hard line.

even things as big as protons still can exhibit wave-like properties

I think there was some publication showing wave-like interference by performing the double-slit experiments with fullerenes, so molecules of about 60 carbon atoms.