Why people believe this
The double-slit experiment shows interference (wave behavior) but photon detectors click discretely (particle behavior). It sounds natural to say light switches between the two depending on the situation.
The correction
Quantum objects are neither waves nor particles in the classical sense — they are quantum objects that have no classical analog. The wave-particle language is a historical accident from trying to describe quantum phenomena using classical concepts. The wavefunction is not a physical wave of anything — it is a probability amplitude. When we say light behaves like a wave, we mean its probability amplitudes interfere. When we say it behaves like a particle, we mean measurements give discrete outcomes. It does not switch — it is always quantum.
Try it in the simulator
What to do
Load the Interference preset. H-Z-H = X shows quantum interference of probability amplitudes — the |0> amplitude and |1> amplitude cancel completely. This is not a wave phenomenon in the classical sense — it is interference of complex numbers in Hilbert space. Run it and see 100% probability of |1>.
Research notes
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