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Science

Physicists Created 'Slits In Time' and Discovered 'Unexpected Physics' (vice.com) 47

Posted by BeauHD from the temporal-analogue dept.
An anonymous reader quotes a report from Motherboard: Scientists have discovered "unexpected physics" by opening up "slits" in time, a new study reports, achieving a longstanding dream that can help to probe the behavior of light and pioneer advanced optical technologies. The mind-boggling approach is a time-based variation on the famous double-slit experiment, first performed by Thomas Young in 1801, which opened a window into the weird probabilistic world of quantum mechanics by revealing the dual nature of light as both a particle and a wave. The new temporal version of this test offered a glimpse of the mysterious physics that occur at ultrafast timescales, which may inform the development of quantum computing systems, among other next-generation applications.

In the original version of the double-slit experiment, light passes through two slits that are spatially separated on an opaque screen. A detector on the other side of the screen records the pattern of the light waves that emerges from the slits. These experiments show that the light waves change direction and interfere with each other after going through the slits, demonstrating that light behaves as both a wave and particle. This insight is one of the most important milestones in our ongoing journey into the quantum world, and it has since been repeated with other entities, such as electrons, exposing the trippy phenomena that occurs at the small scales of atoms.

Now, scientists led by Romain Tirole, a PhD student studying nanophotonics at Imperial College London, have created a "temporal analogue of Young's slit experiment" by firing a beam of light at a special metamaterial called Indium Tin Oxide, according to a study published on Monday in Nature Physics. Metamaterials are artificial creations endowed with superpowers that are not found in nature. For instance, the Indium Tin Oxide used in the new study can change its properties in mere femtoseconds, a unit equal to a millionth of a billionth of a second. This incredible variability allows light waves to interact with the metamaterial at key moments in ultrafast succession, called "time slits," which produces a time-based diffraction pattern that is analogous to the results returned in the spatial version of the experiment. [...] In other words, the super-speedy changeability of Indium Tin Oxide finally made a time slit experiment possible, after many years of eluding scientists. To bring this vision to reality, Tirole and his colleagues used lasers to switch the reflectance of the material on and off at high speeds.
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Physicists Created 'Slits In Time' and Discovered 'Unexpected Physics' More

Physicists Created 'Slits In Time' and Discovered 'Unexpected Physics'

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  • Remember when The Master discovered interstitial time, tried to enslave Kronos, and the Third Doctor stopped him?

  • A slit in time saves nine!

  • Pretty close now just have to figure out how to turn the i into a u and we’ll have something useful.

  • So you say there's a pussy in the box.

    I think you might be slightly mixed up on nomenclature, but we get the idea.

  • Why "slits" instead of "Tunnels"? (Score:3, Interesting)

    by Babel-17 ( 1087541 ) on Tuesday April 04, 2023 @02:57AM (#63424340)

    A lot of us old fogeys would be more likely to favor funding Time Tunnels, lol.

    The Time Tunnel EP 24 Chase Through Time (guest starring Robert Duvall!)

    https://youtu.be/2_YgrsYjrUc [youtu.be]

  • a better summary (Score:5, Informative)

    by vyvepe ( 809573 ) on Tuesday April 04, 2023 @03:03AM (#63424342)
    They were changing reflectance of a meta-material (indium tin oxide) using a laser very quickly (i.e. they were changing how well the meta-material reflects light). They observed a different beam of light after it reflected from the meta-material.
    They found that they can change the reflectance about 10 - 100 times quicker than expected from theory. The reflected beam was frequency modulated. They measured the spectrum of the reflected beam. Some colours were enhanced and some were cancelled out. The level of this was controlled by the frequency of changing the meta-material reflectivity.
    Non-paywalled paper on arxiv: https://arxiv.org/abs/2206.043... [arxiv.org]

    • That makes me wonder if it's just the equivalent of phase cancelation/enhancement that you can do with sound waves. Changing reflectivity implies a change in the surface. What if, as the change occurs, some of the light colors are penetrating just the surface, and some are going a nanometer or more into the material before being reflected back? So you start with all light aligned in waves, and end up with waves overlapping each other, canceling some colors and enhancing others.

      Anybody that's spent more than

      • Re: (Score:2)

        by vyvepe ( 809573 )

        I do not know whether it is similar. I did not look at the math. I was disappointed by the summary which hardly told anything useful. That is the reason I looked at it a bit more and posted.

        But it is not surprising that they observed interesting effects when you realize that the reflectivity was being changed with frequency of about 500 THz (the range of red light) and the probing signal frequency was about 230 THz (short wave infrared).

        Maybe, the more interesting result is that the reflectivity was changi

    • Re: (Score:2)

      by chill ( 34294 )

      Thank you!

  • ...welcome our new Time Slit Overlords.

  • This is significant. (Score:4, Interesting)

    by jd ( 1658 ) <`imipak' `at' `yahoo.com'> on Tuesday April 04, 2023 @06:05AM (#63424492) Homepage Journal

    I do not see how you could get time diffraction if the universe is 3+1 dimensional or if there's no past/future only the present. In the first case, time would behave differently than space and in the second case there'd be no time at all, only "now".

    If this is correct, it's going to drive a lot of anti-Relativity fanatics on Quora into apoplexy, which would be a Good Thing*. There's simply no way of treating time as unique and totally different from space whilst also treating it as a spacial dimension with extra properties. Time has to be one of those two and time diffraction would seem to rule out the former.

    The question I'd ask, though, is whether the interference pattern is symmetric or asymmetric. Regardless of which, the past can presumably affect the future. Otherwise, what's doing the interfering? You have to have two photons minimum before there's interference. A photon cannot (legally) interfere with itself. You need waves in time, not just in space, to get interference. If it is symmetric, the future can presumably also affect the past. The shape of those waves will determine the shape of the interference pattern and therefore limit what can interfere with what.

    I could not fully understand the diagrams in the paper, so couldn't really follow what they actually observed, but I -think- they observed the latter, which would be very interesting. If I understand this correctly, it would imply quantum uncertainty applies to spacetime, not just space. But I could easily be wrong about that. Quantum Mechanics is hell for those outside the subject to fully understand. Mind you, it's not easy for those on the inside, either.

    But if this experiment proves spacetime applies to QM, then that's going to do some interesting things to QM as I don't think they've got QM to work with time yet, only space. But if time is just the same as space at that level, then that should make a quantum spacetime a relatively simple** addition.

    *See 1066 And All That

    **Simple as compared to, say, either M-theory or grand unified quantum field theory. Not "simple" as in anyone with an IQ under 6000 could understand it easily.

    • Re: (Score:3, Interesting)

      by Anonymous Coward

      But if this experiment proves spacetime applies to QM, then that's going to do some interesting things to QM as I don't think they've got QM to work with time yet, only space. But if time is just the same as space at that level, then that should make a quantum spacetime a relatively simple** addition.

      What I find more interesting is the particular way QM does work with time compared to how it doesn't.

      QM does have relationships that take time into account, but so far the problem is none of those relationships are considered predictive because they lack any relationships to differentiate a "direction"

      One of the more popular assumptions is times direction is a result of entropy, which QM has no relation between it and time.
      That would imply by QM that there is no difference in yet is implied by physics that

    • Not Significant (Score:5, Informative)

      by Roger W Moore ( 538166 ) on Tuesday April 04, 2023 @08:39AM (#63424788) Journal
      This sort of effect has been known for at least a decade or so since there was a paper at least that old describing temporal interference between two photons passing through an apparatus at closely time intervals exactly like this experiment.

      A photon cannot (legally) interfere with itself.

      A single photon going through two slits can and does interfere with itself because it is not localised to a point in space. I suppose it is possible that wherever you are there is a law against it doing that if but if the police are going to start arresting all photons then your local police state is going to be facing some dark times ahead.

      But if this experiment proves spacetime applies to QM, then that's going to do some interesting things to QM as I don't think they've got QM to work with time yet, only space.

      Yes we did, about 100 years ago - relativistic quantum mechanics started in 1932 with the Dirac equation. The Standard Model of particle physics is a fully relativistic quantum field theory, treating time and space together using Special Relativity, only GR cannot yet be fully reconciled with QM. You rarely hear about it from people who call themselves "Quantum Scientists" because they are dealing with low energy phenomena but in particle physics we work all the time with relativistic quantum mechanics.

      • Re: (Score:1)

        by BigIrv ( 695710 )

        A single photon going through two slits can and does interfere with itself

        Weird, but totally true.

  • Double-slit time diffraction at optical frequencies
    Archiv: https://arxiv.org/pdf/2206.043... [arxiv.org]
    Non-Academic article:
    https://physicsworld.com/a/phy... [physicsworld.com]

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