Undergrad Delayed Choice Double Slit: Sending Info to the Past?

[chad hale]

This is a proposed idea. Using the "Delayed choice" version of the double slit experiment, can you devise a way to send Information (in this case the winning lotto numbers) Into the past?
I imagine that one could convert the winning numbers into binary, assigning a 1 for wave experiments, and 0 for particle experiments. Conduct all the trials in the assigned order.
Days before, a priori, you observe the data...ERM, something like that...

 

[Nugatory]

The short answer to your question is "no". No matter what the setup is, when the problem is analyzed properly it will turn out that there is no way to send a message into the past.

However, you probably want to know why it's "no", and for that you'll have to tell us more. Exactly what are we measuring, exactly how do we interpret the result as a one or a zero, and exactly what action does the guy in the future take to send us that one or zero?

 

[DrChinese]

This is a proposed idea. Using the "Delayed choice" version of the double slit experiment, can you devise a way to send Information (in this case the winning lotto numbers) Into the past?
I imagine that one could convert the winning numbers into binary, assigning a 1 for wave experiments, and 0 for particle experiments. Conduct all the trials in the assigned order.
Days before, a priori, you observe the data...ERM, something like that...

I am making an educated guess here as to your intent.

Yes, you can perform delayed choice experiments. But the "choice" itself contains/creates a random factor - this point is usually not mentioned. The person making the choice can see that random factor. But it resides in the future. Without knowing the random factor itself - which is not available to the persons in the past - the choice (message) cannot be interpreted.

Please be aware that most of the delayed choice experiments are quite complex. So it is very difficult to explain the issue in a meaningful manner. But here is a greatly simplified example. You can entangle particles after the fact (ie in the future). Entangled particles will exhibit so-called perfect correlations, and those can be observed in the present. So it should be easy to detect that and send a signal from the future to the past, right? The problem is that there are 2 types of such entanglement: + and -. The person in the future cannot select which type to create - that is purely random. That person can see which is created, but has no way to send that extra bit of information to the past - which is needed to make sense of the results the person in the past sees.

 

[Strilanc]

PBS SpaceTime did the "Why can't you win the lottery with delayed choice?" as one of their viewer challenges.

You can see the video containing the solution here (jump to the 4 minute mark):



And you can see the challenge video here:



The basic reason it doesn't work is that you don't ever see an interference pattern. You use the "erasure" measurement results to group the original measurements, which were just an indistinct blur, into two groups. The two groups will have interference patterns, and they sum to the lack-of-interferece that you saw, but you need the later measurement results to do the grouping.