Physics
Wavefunction Collapse
A matter wave spreads through space as a cloud of probability, until something measures it and it is found at one single point. Measure a packet, split it into two places at once, or fire particles one by one at a screen and watch the interference fringes build up dot by dot.
probability density |ψ|²phase arg ψ (hue)detection
Click empty space to measure · drag to orbit · scroll to zoom
Spread σ—
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Scene
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Show
Plane
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Values
time t—
width σ(t)—
⟨r⟩—
last found at—
measurements—
What to observe
- A free packet spreads as it moves. Measure it and the whole cloud collapses to one point, which then spreads again, faster the sharper the detector: a narrow σm fixes the position and leaves the momentum uncertain.
- In Two places at once a measurement finds the particle in one place only, each about half the time. Let the halves spread into each other first and fringes appear: both halves were really there.
- At the detector screen every particle lands as a single dot, wherever the wave was. One dot shows no pattern; hundreds of them draw theinterference fringes.
- With colour by phase on, the hue turns once every wavelength 2π/k, so the stripes on a moving packet are its momentum. Raise k and they crowd together.
Shortcuts:space run/pause · s step · r reset · f fullscreen