This experience is known as the delayed-choice quantum eraser. At first, the experiemnt might seems like if a measurment made in the present can alters one made in the past, but in fact, considering the photon in a superposition of state makes it work. This experiment was first realise in 1998 (mettre une référence) and was done a second time in Brazil in 2008 [ref...] in a slitly diffrent setup, more similar to the one will are doing.One one of the path, we have a double slit. Without entangled photon, we would get interference. This experiment shows that when we have entengled photon, the detctor D1 will never get alone interference, even if photon passed through the double slit. That curve is the one in purple in the following animation. But, when we look at the coincidence between D1 and D2, we get different results depending on the angle of all polarizers. That pattern is drawn is pink.
This experience is known as the delayed-choice quantum eraser. At first, the experiemnt might seems like if a measurment made in the present can alters one made in the past, but in fact, considering the photon in a superposition of state makes it work. This experiment was first realise in 1998 (mettre une référence) and was done a second time in Brazil in 2008 [ref...] in a slitly diffrent setup, more similar to the one will are doing.One one of the path, we have a double slit. Without entangled photon, we would get interference. This experiment shows that when we have entengled photon, the detctor D1 will never get alone interference, even if photon passed through the double slit. That curve is the one in purple in the following animation. But, when we look at the coincidence between D1 and D2, we get different results depending on the angle of all polarizers. That pattern is drawn is pink.
