3 ms·
This one of the great (originally thought) experiments, but it comes with a serious fundamental caveat... ...although there is a 50% chance that the bomb will
by QAPereo 9y ago
This one of the great (originally thought) experiments, but it comes with a serious fundamental caveat...
...although there is a 50% chance that the bomb will explode in the effort.
Of course you could imagine using this device and a massive thermonuclear bomb on your lap to test notions of so-called Quantum Immortality. Please note that YMMV when attempting to play that game.
- Strilanc 9y agoYou can tweak the experiment to get arbitrarily close to 0% chance of exploding the bomb. Instead of using a 50/50 beam splitter and passing the photon through the system once, you pass the photon many times while gradually rotating it from the free path onto the bomb path. If the bomb isn't present, you end up with a photon on the empty bomb path. If the bomb is present, the zeno effect will keep the photon on the free path. Then you just check which path it ended up on in the end.
- saagarjha 9y agoYes, but doesn't the repeated application increase the probability again? How is this bringing it closer to 0%?
- Strilanc 9y agoFor a rotation angle of x° the probability of failure for each check+rotate when a bomb is present is sin(x°)^2. It takes 90°/x° repetitions of a rotation by x° to get a useful effect in the safe case. So the overall failure rate is 1-(1 - sin(x°)^2)^(90°/x°) or equivalently 1-cos(x°)^(180°/x°). Compute the limit as x goes to 0 and you'll find the limit equals 1. Making x smaller increases the chance of success arbitrarily close to unity.