Reposting (Delayed Choice Experiment)

[lmerriam]

Haste made waste (I managed to get it precisely backwards, sorry. Corrected below. And please, somebody, clue me in here
...

Hello,

I'm uncomfortable with the usual description of this experiment and wonder if this is justified. In a nutshell, when (in the usual double-slit setup) detectors are placed between the barrier and the final screen -- such that an electron, say, has already move past the two-slits -- NO interference pattern will form as though the detection had been made earlier, resulting in the observation of particles instead of waves. It is then suggested that the electron knows it was watched and adjusts its behavior in the past to conform accordingly.

Here's my problem with this ...

Electrons travel at the speed of light where time either does not exist at all, or perhaps simply stops (I recall reading it being the former .. is this correct, btw??). Regardless ... although from our perspective the electron most certainly crossed the barrier before it reached the detector beyond, from the electron's point of view no time elapsed at all; hence, there was no delay to speak of.

Am I missing something?

thanks!

 

[eljose79]

Thank you for bringing up your concerns about the common description of the double-slit experiment. It is understandable that you find the explanation of the electron adjusting its behavior in the past to be confusing. However, I would like to clarify that the electron does not actually "know" it is being watched and adjust its behavior accordingly. This is simply a way of explaining the unexpected results of the experiment.

In reality, the interference pattern disappears because the act of detection itself changes the state of the electron. When the electron passes through the barrier, it exists in a superposition of states, acting as both a particle and a wave. However, when it is detected, it collapses into a single state, either a particle or a wave, depending on the type of measurement being made. This collapse of the wave function is what causes the interference pattern to disappear.

As for your question about time and the speed of light, it is true that the closer an object gets to the speed of light, the slower time appears to pass for that object. However, this does not mean that time stops for the electron. It simply means that time appears to pass at a slower rate for it compared to an observer outside of its frame of reference.

I hope this helps to clarify any misunderstandings you may have had about the double-slit experiment. Keep questioning and seeking answers, as that is the essence of science.