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posted by janrinok on Sunday October 06 2019, @02:05PM   Printer-friendly
from the I-hope-he-has-enough-cats-for-future-experiments dept.

Submitted via IRC for SoyCow9088

2,000 "Schrodinger's Cats" break record for large-scale quantum superposition

The world of quantum mechanics, where particles can be in two places at once or entangled with each other across vast distances, sounds spooky to us living in the macroscopic world of classical physics. But where exactly the boundary between the two lies is still a mystery. Now physicists have blurred the line more than ever before, with a new experiment showing that massive molecules containing up to 2,000 atoms can exist in two places simultaneously.

The discovery was made using an advanced version of an experiment that's been conducted countless times over the last 200 years – the double slit experiment. It was through this experiment that scientists came to understand the duality of light as both particles and waves.

The experiment sounds fairly simple. Light is beamed towards a surface that has two slits cut into it, and another surface behind it that the light ends up projected onto. If light was made up of only conventional particles, then the pattern on the rear surface would just appear in the shape and size of the slits. But waves of light bounce off each other like ripples in water, creating a kind of tiger-stripe pattern on the surface.

But the strangest thing is that even when the experiment is done with individual photons (or particles of light), the same striped pattern appears. Somehow, these photons don't seem to be taking just one path as they might be expected to, but are traversing all of them at once and interfering with themselves.

This phenomenon is known as quantum superposition, and it's most famously illustrated by Schrödinger's Cat. In this thought experiment, a cat hidden in a box is neither alive nor dead, but exists as both at the same time. When the box is opened, this superposition collapses into one state or the other.

By the same token, it's been said that if detectors were set up at the slits, so they were measuring which path the light was taking, the striped patterns would disappear. The fuzziness of the outcome clears up as soon as it's measured.

But superposition only seems to apply in the quantum realm – as objects get bigger, it gets harder for this phenomenon to occur, and by the time you get up to the macroscopic scale it seems to disappear entirely. Even Schrödinger's Cat needs a quantum link – the story often goes that there's a radioactive atom in the box too, and the cat's survival hinges on whether the atom decays or not.

The research was published in the journal Nature Physics.


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  • (Score: 2) by Rupert Pupnick on Sunday October 06 2019, @05:10PM (5 children)

    by Rupert Pupnick (7277) on Sunday October 06 2019, @05:10PM (#903422) Journal

    Yes, there is the experiment using photo detectors that show photons as discrete packets of energy that arrive at discrete times.

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  • (Score: 0) by Anonymous Coward on Sunday October 06 2019, @07:56PM

    by Anonymous Coward on Sunday October 06 2019, @07:56PM (#903474)

    wooosh!

    summary is idiotic. the big deal with the double slit experiment is that it works the same with electrons as with light, not that it works with light.
    the "double slit experiment with light" was well known in the 1800s, and the "weird" light effect was the later photo-electric effect.

  • (Score: 4, Informative) by maxwell demon on Sunday October 06 2019, @09:26PM (3 children)

    by maxwell demon (1608) on Sunday October 06 2019, @09:26PM (#903496) Journal

    Actually the experiment that ultimately proved photons having particle properties was the Compton scattering experiment, which showed that photons bounce from electrons the way particles do.

    --
    The Tao of math: The numbers you can count are not the real numbers.
    • (Score: 0) by Anonymous Coward on Monday October 07 2019, @10:49AM (2 children)

      by Anonymous Coward on Monday October 07 2019, @10:49AM (#903655)

      you mean photo-electric effect, which showed that to push electrons off a chunk of material the frequency of light is important, not its intensity.

      • (Score: 0) by Anonymous Coward on Monday October 07 2019, @03:10PM

        by Anonymous Coward on Monday October 07 2019, @03:10PM (#903719)

        yeah, you gotta find the "right sized" bag of electrons when you want to ionize some atoms at home.
        beware the doddgy electrons they harvest "overseas" which come from over fertilized and not cared-for atoms; half of 'em don't pack the "UMPHf" required to cascade the electrons of at home so netxt time you go to homedepot or whatnot to buy your bag of electrons, be sure to get those sourced locally ...

      • (Score: 2) by maxwell demon on Monday October 07 2019, @04:26PM

        by maxwell demon (1608) on Monday October 07 2019, @04:26PM (#903749) Journal

        No, I mean the Compton effect. The photoelectric effect was what led Einstein to postulate the particle nature of light, but only the Compton effect did remove all doubts about it.

        --
        The Tao of math: The numbers you can count are not the real numbers.