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posted by janrinok on Tuesday January 16 2018, @02:47AM   Printer-friendly
from the lots-of-suck dept.

Physicists Say They've Created a Device That Generates 'Negative Mass'

Physicists have created what they say is the first device that's capable of generating particles that behave as if they have negative mass. The device generates a strange particle that's half-light/half-matter, and as if that isn't cool enough, it could also be the foundation for a new kind of laser that could operate on far less energy than current technologies.

This builds on recent theoretical work on the behaviour of something called a polariton, which appears to behave as if it has negative mass – a mind-blowing property that sees objects move towards the force pushing it, instead of being pushed away.

Now physicists from the University of Rochester have created a device that allows them to actually create these polaritons at room temperature. They do this by manipulating captured photons and combine them with a kind of quasi-particle called an exciton to make something half-light/half-matter that some scientists affectionately refer to as 'magic dust'.

This alone is "interesting and exciting from a physics perspective," says quantum physicist Nick Vamivakas from Rochester's Institute of Optics. "But it also turns out the device we've created presents a way to generate laser light with an incrementally small amount of power."

Anomalous dispersion of microcavity trion-polaritons (open, DOI: 10.1038/nphys4303) (DX)

Previously: Physicists Create 'Negative Mass'


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  • (Score: 2) by JoeMerchant on Tuesday January 16 2018, @09:05PM (5 children)

    by JoeMerchant (3937) on Tuesday January 16 2018, @09:05PM (#623289)

    Fine, so you can build a nucleus out of negative mass particles, then what? These negative mass nuclei are going to scatter.

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  • (Score: 2) by TheRaven on Wednesday January 17 2018, @10:33AM (4 children)

    by TheRaven (270) on Wednesday January 17 2018, @10:33AM (#623519) Journal
    No, they're going to be attracted to electrons by the electromagnetic force. Those electrons are going to bind them to other atoms with ionic or covalent bonds, which use the electromagnetic force. As I said in my previous post, the electromagnetic force is vastly stronger than the gravitational force.
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    • (Score: 2) by JoeMerchant on Wednesday January 17 2018, @01:15PM (3 children)

      by JoeMerchant (3937) on Wednesday January 17 2018, @01:15PM (#623567)

      O.K. now you've made atoms, maybe molecules (wasn't clear to me that the negative mass particles were charged, but... let's say they are)

      toss a chunk out in free space, over time it will disintegrate, just like how over time planets form - from the force of gravity.

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      • (Score: 2) by TheRaven on Wednesday January 17 2018, @01:29PM (2 children)

        by TheRaven (270) on Wednesday January 17 2018, @01:29PM (#623572) Journal

        No it won't. Really. Molecules are held together in large objects by electromagnetic attraction between the nuclei and the free electrons. Do the magnet experiment that I proposed in my original post and you'll see that the electromagnetic attraction from the arrangement of electrons in a few grams of iron is far greater than the gravitational attraction from the entire mass of the Earth. If this were not the case, then any solid object would fall apart as soon as it became close to a planet.

        For objects of only a few tons, the gravitational force holding them together is so small in comparison to the EM force that it's going to be smaller than any rounding errors in your calculations or experimental measurement. If you change the sign on that force, you will not observe any difference.

        If you still don't believe me, put two small plastic objects on your desk in front of you. They are held in place by electromagnetic force between their surface and the surface of the desk (that's what causes friction), they are attracted to each other by their respective gravitational pulls. Get back to me when they move together.

        How did you manage not to learn all of this at school?

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        • (Score: 2) by JoeMerchant on Wednesday January 17 2018, @02:19PM

          by JoeMerchant (3937) on Wednesday January 17 2018, @02:19PM (#623586)

          I know the forces, I know they have differing magnitudes and rates of decay at distance, I know they differ in magnitude by many orders...

          I also know that: there aren't any negative mass asteroids or planets hanging out around our solar system - at least none that we have observed. There aren't any significant (aka observable) quantities of negative mass particles (or quasi-particles) mixed in with any of the objects we have studied.

          In a planet where quantities of uranium sufficient to create a 100kW sustained fission reaction have naturally occurred and left evidence (https://gizmodo.com/there-s-a-naturally-occurring-nuclear-fission-reactor-i-1475445638), I would expect that something like negative mass quasi-particles, if they were inclined to hang together, would have already.

          So, perhaps with great care and energy, like that used to magnetically bottle anti-matter or fusion reactions, you might assemble a large object composed with a significant quantity of negative mass quasi-particles. I'd still call that "hard to handle."

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        • (Score: 2) by Immerman on Wednesday January 17 2018, @02:27PM

          by Immerman (3985) on Wednesday January 17 2018, @02:27PM (#623587)

          However, unless the entire planet has a phenomenal net charge there will be neutral particles present - at which point the attraction of gravity will push them away (unless they had an imaginary gravitational mass, making it a repulsive force)

          Of course... it's actually quite likely that such a planet *would* have a ridiculous charge, negative mass protons would clump together, while -m electrons would be repelled. In fact, since you don't need the nuclear force to hold the protons together, you'd end up with essentially a neutron-star density material. And the electrons... they'd probably form an intensely charged black hole... or an "anti-black hole" if their gravitational mass was also negative... I'm not even sure what that would mean.