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The fastest spinning object on Earth – a pair of nanoparticles – can complete over five billion revolutions per second in the laboratory, according to a paper published in Nature Nanotechnology on Monday.
Here's how the team at Purdue University in the US pulled it off: they formed a dumbbell-shaped object roughly 300nm across in a vacuum chamber from two silica particles. Next, the eggheads zapped the dumbbell with a laser to trap it in place, a process dubbed optical levitation.
A second, slightly less powerful laser beam is focused on the particle to make it spin. The laser light used to trap the nano-dumbbell is passed through a lens and projected onto a series of photodetectors. As the teeny object spins, it alters the polarization of the beam, and that change is used to determine the nanoparticle's record-breaking rotation rate. Thus, the dumbbell also acts as torque detector, we're told.
The goal isn’t to keep breaking records for the sake of it, however. [Tongcang Li, an assistant professor of physics and astronomy, and of electrical and computer engineering at Purdue, who led the study] hopes these strange nanoparticles will help scientists understand so-called “vacuum friction,” a quantum effect in which a particle is slowed down by frictional forces in empty space. Physicists reckon virtual photons pop in and out of existence in a vacuum, such as space, to exert a tiny amount of drag on real particles.
The nanoparticles could be used to measure that drag because, as the university was keen to remind us, the dumbbell forms "the world's most sensitive torque detector, which researchers hope will be used to measure the friction created by quantum effects."
Journal Reference:
Ahn, J., Xu, Z., Bang, J. et al. Ultrasensitive torque detection with an optically levitated nanorotor, Nature Nanotechnology (DOI: doi:10.1038/s41565-019-0605-9)
Abstract:
Torque sensors such as the torsion balance enabled the first determination of the gravitational constant by Henri Cavendish and the discovery of Coulomb's law. Torque sensors are also widely used in studying small-scale magnetism, the Casimir effect and other applications. Great effort has been made to improve the torque detection sensitivity by nanofabrication and cryogenic cooling. Until now, the most sensitive torque sensor has achieved a remarkable sensitivity of 2.9 × 10−24 N m Hz−1/2 at millikelvin temperatures in a dilution refrigerator. Here, we show a torque sensor reaching sensitivity of (4.2 ± 1.2) × 10−27 N m Hz−1/2 at room temperature. It is created by an optically levitated nanoparticle in vacuum. Our system does not require complex nanofabrication. Moreover, we drive a nanoparticle to rotate at a record high speed beyond 5 GHz (300 billion r.p.m.). Our calculations show that this system will be able to detect the long sought after vacuum friction near a surface under realistic conditions. The optically levitated nanorotor will also have applications in studying nanoscale magnetism, and the quantum geometric phase.
(Score: 4, Informative) by Mojibake Tengu on Wednesday January 22 2020, @07:57PM (8 children)
You can read this article for free too.
https://arxiv.org/abs/1908.03453 [arxiv.org]
Why Soylent always prefers linking scientific articles on commercial non-free outlets, when free edition is available?
Respect Authorities. Know your social status. Woke responsibly.
(Score: 2) by Freeman on Wednesday January 22 2020, @08:28PM
I'm going with volunteers seeing a story and the story not having the link easily accessible, entirely missing, or they just didn't pay that much attention.
Joshua 1:9 "Be strong and of a good courage; be not afraid, neither be thou dismayed: for the Lord thy God is with thee"
(Score: 0) by Anonymous Coward on Wednesday January 22 2020, @08:53PM (1 child)
also when the source is The Register, with their annoying britslang and flouncy wording
(Score: 2) by progo on Thursday January 23 2020, @05:12AM
"annoying britslang and flouncy wording"
I'll bet no one in UK talks like that except The Register itself. NYC media has annoying habit of calling public transit riders "straphangers"; literally no one else uses that word, and there are no straps.
(Score: 2) by Mykl on Wednesday January 22 2020, @09:17PM
Probably because the article provides a better introduction and context for less technical minds. Sometimes the articles will include interview quotes from the authors too, which can be interesting additions to the content of the paper.
(Score: 2) by krishnoid on Wednesday January 22 2020, @10:11PM
You can also view the abstract on Pubmed [nih.gov] if you want to bookmark it later. Clicking on it, hey, there's a banner showing that they have a new website layout [nih.gov], let's try it out ... noooooooo! Another whitespace victim!!!
(Score: 2, Touché) by Anonymous Coward on Wednesday January 22 2020, @10:44PM (1 child)
Blame the Arthur T Knackerbracket parents.
Just abstain from blaming editors until you don't start making submission yourself - the last I know, S/N is short on editorial effort capavity.
(Score: 2) by Bot on Friday January 24 2020, @03:20PM
Indeed.
Editors needed to run the site: 3, plus
Editors needed to reject Aristarchus "submissions", 7.
10 editors is a lot of staff nowadays.
Account abandoned.
(Score: 2, Interesting) by RandomFactor on Thursday January 23 2020, @02:50AM
Pretty sure i remember the submission guidelines recommending using free links where possible somewhere.
I have often wished SN had a way to comment (invisibly) against submissions. E.g. point out typos, alternate links, things like that which might be useful for editors.
В «Правде» нет известий, в «Известиях» нет правды