The Elitzur-Vaidman Bomb Tester

University College London - Dept. of Physics and Astronomy
Concept video for PHAS0035

Credits:
GHICA Ana-Cristina - video editing, script
ZHU Baien - script
WAISMAN ANDRADE David - script
PARASCHIV Andrei-Alexandru - script

Links:

[charlesolarte]

Question: Wasn't the purpose of the experiment is to determine for certain, if a bomb is a dud or not without detonating it? But according to the explanations I saw, you explode the bomb almost 50% of the time, and only know for certain its not a bomb if its measured in Detector A (detection from B means its still either a dud or a live, repeatable if necessary).

Even if the bomb wont explode due to quantum superposition, activating Detector B still means you're unsure if its a dud or not. Repeating the experiment continously for the B bombs and keep activating Detector B still doesnt mean it's a dud, but rather that it can also still be a live one and just didnt get the A result yet. The experiment is only true for the bombs that have the A result at the get go. All the "B" bombs are still in superposition; theyre both live and duds, until you keep repeating the test and get the A. But then how many times do we need to repeat test the B bombs for us to be sure they're not really live ones that just got the B result? Even if we test a B bomb a million times and get B, we are still not 100% sure if its a live or dud. Still in superposition.

So what's the point of the experiment?