Double-Slit
The Experiment
Fire particles at a barrier with two slits. Watch where they land.
Each dot is one particle hitting the detector. The pattern emerges statistically.
Try this
Watch particles arrive one at a time.
Turn the Observer ON, what changes?
Turn it OFF again, the pattern returns.
What this reveals
Each particle lands randomly. The pattern only emerges after many hits. There's no wave on the screen, only accumulated probability.
Knowing which slit the particle went through forces it to behave classically. The information itself matters.
The particle's wavefunction passes through both slits and interferes with itself. The screen shows where it's likely to land.
Photons, electrons, atoms, even molecules. Quantum behavior isn't about size. It's about isolation from measurement.
Expectation vs reality
Toggle to compare.
This is the same phenomenon
The wavefunction passes through both slits. The particle exists in multiple states until measured.
Observation forces one outcome. Reading a qubit destroys its quantum state for the same reason.
Probability amplitudes add and cancel. Quantum algorithms exploit this to amplify correct answers.
A qubit is a system designed to stay in this strange state long enough to compute.