The quantum eraser delayed choice experiment is a fascinating quantum phenomenon that involves the manipulation of entangled particles to observe interference patterns or particle-like behavior. While it may seem counterintuitive, this experiment does not allow for the transmission of information faster than the speed of light.
In the quantum eraser experiment, the interference pattern or particle-like behavior depends on whether or not information about the path of a particle is accessible or has been erased. When the path information is available, the interference pattern disappears, and when the path information is erased, the interference pattern reappears.
However, it's important to note that this phenomenon does not enable faster-than-light communication or the transmission of information. The delayed choice aspect of the experiment refers to the decision to observe or erase the path information after the particles have already passed through the setup.
While the interference pattern on the screen may appear to change immediately when the detectors are turned on or off, it does not imply that information is being transmitted instantaneously. The apparent instant change is a consequence of the quantum nature of the experiment and the entanglement between the particles involved. The actual transmission of information still adheres to the speed of light limitation and cannot be used to communicate at superluminal speeds.
In summary, the quantum eraser delayed choice experiment does not violate the principle of causality or allow for faster-than-light communication, even though the observations of the interference pattern may appear to change instantaneously.