The quantum eraser experiment does not actually rewrite the past. It is a thought experiment and a real experiment in quantum physics that demonstrates the counterintuitive behavior of particles at the quantum level.
In the quantum eraser experiment, the behavior of particles, such as photons or electrons, is observed through a double-slit setup. When a particle passes through the double slits, it behaves as both a particle and a wave, creating an interference pattern on a screen behind the slits. This interference pattern indicates the wave-like behavior of the particle.
However, if we introduce a measurement device that determines which slit the particle goes through, the interference pattern disappears, and the particle behaves strictly as a particle, creating two distinct bands on the screen. The act of measurement collapses the wave function, and the particle's behavior becomes deterministic.
In the quantum eraser version of the experiment, a delayed choice is introduced. After the particles have passed through the double slits but before their final detection, the measurement device is removed or the information about which slit the particle went through is erased. Surprisingly, this erasure of information results in the reemergence of the interference pattern on the screen.
While this experiment might seem paradoxical and counterintuitive, it does not actually rewrite the past. The interference pattern observed on the screen after the erasure of information is still a result of the particle's behavior before the information was erased. It demonstrates that the behavior of particles can be retroactively influenced by the measurement choices made in the present, but it does not imply a rewriting of the past.
The quantum eraser experiment highlights the peculiar nature of quantum mechanics, where the act of observation or measurement can affect the behavior of particles and their associated probabilities. However, it does not have any implications for rewriting or altering events that have already occurred in the past.