No, the quantum eraser does not rewrite the past. The concept of the quantum eraser is a thought experiment used to illustrate certain principles in quantum mechanics, specifically related to the wave-particle duality and the nature of quantum measurement.
In the quantum eraser experiment, a particle, such as a photon, is sent through a double-slit apparatus, which creates an interference pattern on a screen behind it. The particle behaves as a wave and exhibits interference, showing wave-like characteristics.
However, if a detector is placed to determine which slit the particle passes through, the interference pattern disappears, and the particle behaves more like a classical particle, showing particle-like characteristics. The act of measurement or observation collapses the wavefunction, causing the particle to behave differently.
In the quantum eraser setup, an additional element is introduced: entangled particles or "quantum-eraser" particles. These particles are entangled with the particle going through the double-slit, such that information about the path taken by the particle can be deduced from the entangled particles.
The key idea is that, by manipulating the entangled particles after the particle has passed through the double-slit but before the measurement is made, it is possible to "erase" or eliminate the information about the path taken. As a result, the interference pattern on the screen is restored, indicating the wave-like behavior of the particle.
However, it is important to note that the quantum eraser does not actually rewrite the past. The particle's behavior in the past is determined by the interactions it undergoes and the measurements made on it. The quantum eraser experiment does not change the actual events that occurred; rather, it demonstrates the role of measurement and the wave-particle duality in influencing the observed outcomes.
The quantum eraser experiment highlights the counterintuitive nature of quantum mechanics and the complex relationship between measurements, wavefunctions, and entanglement. It does not imply that events in the past can be altered or rewritten.