What's a quantum mechanics misconception you believed for years before finally correcting it

[NatureBoy86]

Believed for years that entanglement let information travel faster than light, took an actual course to learn that measurement correlations don't transmit any usable signal at all, no causality violation involved

[IronQuarry]

Thought observation meant a conscious mind had to look at something for collapse to happen, actual physics just means any interaction with the environment counts, consciousness has nothing to do with it

[Cole_25]

Believed quantum effects only mattered at the atomic scale and had zero macroscopic relevance, learned later that superconductivity, lasers and MRI machines all depend directly on quantum mechanics at scales you can touch

[LivMorgan]

Thought Schrodinger's cat was a real experiment someone actually ran, took embarrassingly long to learn it was purely a thought experiment meant to illustrate a problem with the interpretation, not a demonstration of anything

[Harper84]

Assumed uncertainty was about measurement limitations from clumsy instruments, the actual principle says the values themselves don't simultaneously exist to any precision, better instruments can't fix it

[Jordan_68]

Believed particles were tiny solid balls that just happened to behave weirdly, took longer than I'd like to admit to actually internalize that the wave description isn't a metaphor, it's the more accurate picture

[SingularityNodeWrench]

Assumed entanglement was rare and fragile in a way that made it purely theoretical, learned it's routinely created and used in real labs constantly, the fragility is about maintaining it against noise, not creating it in the first place

[Elk31]

Thought quantum computers work by trying every answer simultaneously and picking the right one, the actual mechanism is interference between amplitudes cancelling wrong answers and reinforcing right ones, a different process