Elitzur–Vaidman bomb tester

https://youtu.be/RhIf3Q_m0FQ?t=334 https://en.wikipedia.org/wiki/Elitzur%E2%80%93Vaidman_bomb_teste Common sense tell us that we cannot know a bomb will definitely explode without exploding it. But there is an Experiment of quantum mechanicals called Elitzur–Vaidman bomb tester claimed it can. There are many video already explained the Experiment. But they all concluded the phenomenon is weird and couldn’t understand. This video explained details further and you will find it is so easy to understand and nothing is weird. To understand the experiment, please watch the video. I put the link below. In the video at 8:50 said: if the photon goes to detector B that can only happen if the bomb is life and didn't explode. In the video at 7:54 said: if the bomb is live but doesn't go boom you know the photon is in the upper path. Then … 25% goes to detector B. So the photon goes to detector B can only happen when the photon go through the upper path. Not "the bomb is life and didn't explode". And the photon goes through the upper path can happen when the lower path is blocked. Or the detector at lower pass (not bomb) shift the half photon wave's phase by 90 degree make the two part of photon constructively interference into detector B. Nothing is weird here. So the key misunderstanding here is why the photon go through the upper path can equal to the bomb is life and didn't explode . The bomb is a photon detector on the lower pass. The photon was split and took both upper and lower pass toward right-up sensor A and B. There are three possible scenarios: Scenario number one: The bomb detected a photon. What happened is that the photon was absorbed by the bomb detector. means the superposition or the wave-function collapsed on detector X. not just the lower pass wave. The photon waves on both upper and lower paths were absorbed. So both detector A and B will not detect photons. This means the bomb is live and exploded. Scenario number two: The bomb not-detected photon and the photon went to detect A. What happened is the photon wave function passed both upper and lower pass without interaction. This means the bomb is dud. Scenario number three: The bomb not-detected photon and the photon went to detect B. What happened is the photon wave function passed both upper and lower pass with interaction with the bomb tester. But instead of collapsing its wave function releasing its energy triggering the bomb, the half-wave's phase was shifted 90 degrees when it passed through the bomb detector. That’s why in the end two parts of wave constructive interference into detector B. So the bomb did something to the superposition wave without making it collapse. It just shifted its phase without absorbing its energy. This means the bomb tester found the bomb is live without it being exploded. the photon wave shifted its phase means the bomb is alive. the superposition wave didn't collapse means bomb is not exploded It is not weird, right? Can it test the bomb without exploding? Actually, NO. The reason we think it is impossible to tell if the bomb is good without explosion is because it is an un-repeat event. We can’t be sure it is going to happen until it happens, and after it happens it cannot happen again. But the bomb tester is only proving it interacted with the photon wave at last time and assumes it can repeat next time. But indeed it didn't trigger the explosion. How can it be sure the bomb is alive? What if the bomb only got trigger mechanism without ammunition. So don’t worry. Our common sense survived. But the point here for quantum mechanics is interacting the wave function doesn't necessarily collapse it. That is why the experiment is called interaction-free measurement Quantum mechanics do need to upgrade here: Interacting the wave function doesn't necessarily collapse it. Another thing I need to talk about is when I say wave-function was collapsed on the bomb detector or photon was absorbed by the bomb detector, what exactly happened? The photon wave on both passes was far away from each other, why suddenly all its energy went to the bomb detector?