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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, @09:56PM (3 children)

    by Rupert Pupnick (7277) on Sunday October 06 2019, @09:56PM (#903502) Journal

    I’m not volunteering to be a test subject or anything, but given that I weigh about 180 lbs, I bet you maxwells demon could give you all the necessary parameters like slit spacing and size to run the test to find out.

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  • (Score: 2) by c0lo on Monday October 07 2019, @01:24AM (2 children)

    by c0lo (156) Subscriber Badge on Monday October 07 2019, @01:24AM (#903537) Journal

    I bet you maxwells demon could give you all the necessary parameters like slit spacing and size to run the test to find out.

    Yeah, well, it's a bet. Some, especially scientists, try as hard as possible to avoid betting...

    I’m not volunteering to be a test subject or anything, but given that I weigh about 180 lbs, ...

    ... so don't hold against them if they organize experiments using Rupert Pupnicks to validate what that maxwells daemon could give.

    But... mmmm... you may be safe, unless you diet yourself down to a weight of 21.76470 μg (the Plank mass) [wikipedia.org]. But again, you never know what those scientists may try:

    Whether objects heavier than the Planck mass (about the weight of a large bacterium) have a de Broglie wavelength is theoretically unclear and experimentally unreachable; above the Planck mass a particle's Compton wavelength would be smaller than the Planck length and its own Schwarzschild radius, a scale at which current theories of physics may break down or need to be replaced by more general ones

    --
    https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
    • (Score: 2) by Rupert Pupnick on Monday October 07 2019, @01:04PM (1 child)

      by Rupert Pupnick (7277) on Monday October 07 2019, @01:04PM (#903678) Journal

      Planck Mass! Why didn't you (or someone else, like an author of a referenced article) say so sooner? It's very helpful in putting things in perspective, thanks.

      According to the Nature Journal article, the test molecules have a mass of over 25000 Da which I calculate to be about 4 x 10^-26 g. That's more than 20 orders of magnitude smaller than the Planck Mass of about 2 x 10^-5. Seems like they've got a ways to go before they can expect that limitation to affect the experiment.

      As to scientists and bets, well it seems to me scientists make bets all the time, but usually with other people's money in the form of grants. The question is how good are the bets in terms of expected value of return versus the money going in.

      • (Score: 2) by c0lo on Monday October 07 2019, @01:49PM

        by c0lo (156) Subscriber Badge on Monday October 07 2019, @01:49PM (#903690) Journal

        Seems like they've got a ways to go before they can expect that limitation to affect the experiment.

        Hey, ho! Don't be that dismissive. The current experimental conditions still deal with wavelengths of femtometers - that's 5 orders lower than the typical size of atoms, in the magnitude range of proton sizes.

        --
        https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford