Physicists demonstrate a time mirror for the first time, reversing electromagnetic waves in a laboratory led by Dr. Hussein Moussa.

This sort of time flip has been described as looking into a mirror and spotting your back instead of your face…By carefully adjusting electronic components on a strip of metal, they introduced a sudden jump that reversed the direction of incoming signals…The outcome was a time-reversed copy of the original wave, appearing just as predicted but never before seen with clarity…A wave that can jump to a new frequency and then rewind might open new possibilities for data transmission at different ranges of the spectrum. It could also reshape how certain sensors and imaging systems are designed.

    • itsathursday@lemmy.worldEnglish
      58·
      1 year ago

      And here are some answers:

      https://www.eurekalert.org/news-releases/982119

      (a) Conventional spatial reflections: A person sees their face when they look into a mirror, or when they speak the echo comes back in the same order. (b) Time reflections: The person sees their back when they look into a mirror, and they see themselves in different colors. They hear their echoes in a reversed order, similar to a rewound tape. © Illustration of the experimental platform used to realize time reflections. A control signal (in green) is used to uniformly activate a set of switches distributed along a metal stripline. Upon closing/opening the switches, the electromagnetic impedance of this tailored metamaterial is abruptly decreased/increased, causing a broadband forward-propagating signal (in blue) to be partially time-reflected, (in red) with all its frequencies converted. (Adapted from Nature Physics)

      So kinda like running a sound wave through a flip/reverse filter in audacity and having it switch along the “time” axis.

          • peoplebeproblems@midwest.socialEnglish
            8·
            1 year ago

            I think the neat part isn’t that - it’s neat because of the time component doing it.

            Yet another strange phenomenon of the quantum realm that seemed impossible but is infact real.

            If I remember thinking back to my class on QED, we specifically ignored this solution because there wasn’t a real world demonstration of it (which was ironic, as one of my professors was working on the problem in her doctorate).

            Makes me want to find that book.

            Edit: I might be wrong, I’m thinking of deriving something out of Hilbert Space to Dirac-von Neumann axioms

      • naeap@sopuli.xyzEnglish
        10·
        1 year ago

        An upvote wasn’t enough.
        Thank you!

        I have only skimmed the eureka alert article, but already on the surface it’s so much better than… whatever the fuck that originally-linked thing is.