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Three Quantum Moves
Lean a switch and watch it snap, shrink the wrong answers, then wire two switches together. The same pictures as the videos, in your hands.
Move 1 of 3 · Superposition
A switch that leans
A normal switch is up or down. A qubit is a switch stuck in between, and it leans. The lean decides which way it is more likely to go. Check it, and it snaps fully to one side.
Try this
- Check the leaning switch. Watch it snap.
- Check it again without touching it. Does it move?
- Lean it most of the way up, then check 100.
Real names: the lean, before anything checks it = superposition. The snap = collapse. The switch is not secretly up or down while it leans. It has not picked yet.
Move 2 of 3 · Interference
Shrink the wrong answers
A quantum computer does not check every answer at once. Every answer carries a wave, and waves add or cancel, like noise-cancelling headphones. Each round tags the right answer. Interference shrinks the rest and grows it.
Try this
- Look 100 before any round. How often is it right?
- Run a round. Watch the tag, then the shrink.
- Run a second round, then look 100.
Real names: each answer's wave = its amplitude. Waves adding or cancelling = interference. This recipe is Grover's search. Every look here is a fresh run. More rounds are not always better: past the best number, the right answer shrinks again.
Move 3 of 3 · Entanglement
Two switches, wired together
Picture two switches sent to opposite sides of the planet. Neither is up or down, not yet. Check one and it settles. The other settles the opposite way. Every time.
Try this
- Separate switches: check 100 pairs. How often are they opposite?
- Wire them together and check one pair.
- Still wired: check 100 pairs. Any that are not opposite?
Nothing travels between them. No signal, no message. Switch A on its own is a plain coin flip, so this cannot send anything faster than light.
Real names: wired together = entangled. Einstein called it "spooky action at a distance". Two switches set opposite in advance could fake this game. Ruling that out takes a harder experiment called a Bell test, and real entangled pairs pass it.
Quick check · 3 questions · under a minute
Did it land?
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Thanks. That is exactly the number we are after.
Watch the one-minute versions
Behind the sim
What I simplified
Every result is drawn at random in your browser from the standard rules for one and two qubits, so your tallies wobble around the odds, as real measurements do. The switch is a picture, not the physics. Move 2 runs Grover's search on 8 answers: the chance of the right one is 1 in 8 before any round, about 78% after one round and about 94.5% after two, and a third round would lower it. Two switches set opposite in advance could fake the result in Move 3. Ruling that out takes a Bell test, which entangled pairs pass.
Sources (4)
- Basics of quantum information (course)quantum.cloud.ibm.com
- L. K. Grover, "A fast quantum mechanical algorithm for database search" (1996)arxiv.org
- Press release: The Nobel Prize in Physics 2022nobelprize.org
- Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometresnature.com
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