Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I A two-fold quantum delayed-choice experiment

  1. Sep 24, 2016 #1
    Hello everyone, I am not a physicist but I have been studying this subject. I came across an article and I'm having trouble understanding. I would appreciate if you could help me.


    Last edited: Sep 24, 2016
  2. jcsd
  3. Sep 24, 2016 #2

    Zafa Pi

    User Avatar
    Gold Member

    If what you are interest in is the delayed choice experiment there are easier ones than your link (look around the web until one strikes your fancy).
    In the 2nd paragraph of the body he says that you will notice interference fringes if BS_2 is present. That is not my understanding (whatever it means), rather all clicks will happen at D_1.
  4. Sep 24, 2016 #3
    Thanks for the reply Zafa. I've seen a lot of delayed choice experiments, but this one adds something.
    Actually the experiment I was refering to is this one. My mistake in the first post, the one there is justa gedanken experiment, very similar.


    Here some intertesting things:

    *WPD = which-path detector

    "The quantum properties of the WPD allows erasure of the which- path information associated with the post-selected particle- like behavior, implementing a two-fold delayed-choice pro- cedure and illustrating the wave-particle complementarity in an unprecedented manner."

    "The two-fold delayed-choice procedure provides a clear demonstration that the behavior with or without interference is not a realistic property of the test system: It depends not only on the delayed choice of the WPD’s state, but also on how we later measure the WPD and correlate the outcomes with the data of the test system."
  5. Sep 25, 2016 #4


    User Avatar
    Science Advisor

    Quirk will happily simulate the circuit from that paper for you for various parameters:


    It can also do the circuits from the other paper.

    One thing you need to watch out for in these experiments is: when they say erasure, do they mean post-selection? Often they end up talking about the amazing powers of accidentally cherry-picking data instead of talking about quantum mechanics specifically.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted