World's fastest man-made spinning object could help study quantum mechanics

July 20, 2018 by Kayla Zacharias, Purdue University
Tongcang Li and Jonghoon Ahn have levitated a nanoparticle in vacuum and driven it to rotate at high speed, which they hope will help them study the properties of vacuum and quantum mechanics. Credit: Purdue University/Vincent Walter

Researchers have created the fastest man-made rotor in the world, which they believe will help them study quantum mechanics.

At more than 60 billion revolutions per minute, this machine is more than 100,000 times faster than a high-speed dental drill.

"This study has many applications, including ," said Tongcang Li, an assistant professor of physics and astronomy, and electrical and computer engineering, at Purdue University. "We can study the extreme conditions different materials can survive in."

Li's team synthesized a tiny dumbbell from silica and levitated it in high using a laser. The laser can work in a straight line or in a circle—when it's linear, the dumbbell vibrates, and when it's circular, the dumbbell spins.

A spinning dumbbell functions as a rotor, and a vibrating dumbbell functions like an instrument for measuring tiny forces and torques, known as a torsion balance. These devices were used to discover things like the gravitational constant and density of Earth, but Li hopes that as they become more advanced, they'll be able to study things like and the properties of vacuum.

Researchers have created the fastest man-made rotor in the world by spinning a nanodumbbell with a circularly polarized laser. Credit: Purdue University/Janghoon Ahn

"People say that there is nothing in vacuum, but in physics, we know it's not really empty," Li said. "There are a lot of virtual particles which may stay for a short time and then disappear. We want to figure out what's really going on there, and that's why we want to make the most sensitive torsion balance."

By observing this tiny dumbbell spin faster than anything before it, Li's team may also be able to learn things about vacuum friction and gravity. Understanding these mechanisms is an essential goal for the modern generation of , Li said.

A nanodumbbell levitated by an optical tweezer in vacuum can vibrate or spin, depending on the polarization of the incoming laser. Credit: Purdue University photo/Tongcang Li

Explore further: Levitating nanoparticle improves 'torque sensing,' might bring new research into fundamentals of quantum theory

More information: Jonghoon Ahn et al. Optically Levitated Nanodumbbell Torsion Balance and GHz Nanomechanical Rotor, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.121.033603 , https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.033603

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24 comments

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mscir
1 / 5 (2) Jul 20, 2018
Why only 60 GHz?
bostontola
4.3 / 5 (6) Jul 20, 2018
You mean 1 GHz.
mscir
3.7 / 5 (3) Jul 20, 2018
"At more than 60 billion revolutions per minute"
1,000 = 1kHz
1,000,000 = 1MHz
1,000,000,000 = 1GHz
Whydening Gyre
5 / 5 (1) Jul 20, 2018
Regardless, that's one fast spin rate for matter...
checksinthemail
not rated yet Jul 21, 2018
How fast is that in speed of light? What's the maximum possible speed for two 200nm spheres?
Ralph
5 / 5 (2) Jul 21, 2018
How fast is that in speed of light? What's the maximum possible speed for two 200nm spheres?

I'm not sure exactly what you mean, but if you are referring a system with a radius of 200 nm and a velocity of c, I get 2.4 * 10^14 Hz as the rotation rate.
granville583762
5 / 5 (2) Jul 21, 2018
Mighty objects come in nano packages in the vacuum
1GHz - 170-nm-diameter nano-dumbbell to rotate beyond 1 GHz
A pretty nifty centrifugal acceleration at 510m/s is 3,060billion m/s*
All spinning in the vacuum relying on the electrons electric and magnetic field to hold the silica molecule from breaking apart
A spinning silica molecule with a infinitely larger acceleration than a super massive light radius star
antialias_physorg
5 / 5 (1) Jul 21, 2018
How fast is that in speed of light?

C'mon, you went to school, right? You should be able to figure this out.
bostontola
3.4 / 5 (5) Jul 21, 2018
GHz is cycles per second.
Surveillance_Egg_Unit
5 / 5 (2) Jul 21, 2018
One GHz represents 1 billion cycles per second
bostontola
5 / 5 (3) Jul 22, 2018
Right, cycles per second, not cycles per minute as in the write up.
Da Schneib
5 / 5 (1) Jul 22, 2018
Dividing by 60 is really tough. If you didn't graduate from junior high.
Da Schneib
not rated yet Jul 22, 2018
How fast is that in speed of light?

C'mon, you went to school, right? You should be able to figure this out.

To be fair they'd need the distance between the centers of mass of the particles.
Surveillance_Egg_Unit
5 / 5 (2) Jul 22, 2018
Right, cycles per second, not cycles per minute as in the write up.

says bostontola

From the article: "At more than 60 billion revolutions per minute, this machine is more than 100,000 times faster than a high-speed dental drill."
There are 60 seconds in a minute, therefore, at 1 billion cycles/revolutions/spin per second = 60 billion revolutions per minute.
humy
5 / 5 (3) Jul 22, 2018
I'm glad my balls aren't rotating like that.
mscir
4 / 5 (3) Jul 22, 2018
You mean 1 GHz.

Quite right, I missed that it was 60 M / minute, thanks.
Thorium Boy
5 / 5 (1) Jul 22, 2018
So at what speed does the thing just explode?
TopCat22
5 / 5 (1) Jul 22, 2018
So at what speed does the thing just explode?


I second this question.

Would be interesting to know at what speed the strong force is not longer strong enough to hold elementary particles together. Should be a known value. based on calculations
antialias_physorg
5 / 5 (1) Jul 22, 2018
To be fair they'd need the distance between the centers of mass of the particles.

That's given in the linked article and can also be seen in the video (diameter if the two-particle object is 170nm)
antialias_physorg
3.7 / 5 (3) Jul 22, 2018
So at what speed does the thing just explode?


Here's the link to values about Silica.
The ones you'll need to do the calc are tensile strength and density

From those you should be able to do this with a school math background
mscir
5 / 5 (1) Jul 22, 2018
...Here's the link to values about Silica....

Link pls.
Tessellatedtessellations
1 / 5 (1) Jul 22, 2018
I'm glad my balls aren't rotating like that.

Speak for yourself. In situations of public exposure, tis the light that drives me dizzy nuts, but tis their weeness that turns me face orange with inadequacy and fills me mouth with pathetic bragging and lying spin.
Da Schneib
2.3 / 5 (3) Jul 22, 2018
To be fair they'd need the distance between the centers of mass of the particles.

That's given in the linked article and can also be seen in the video (diameter if the two-particle object is 170nm)
So what's the center-to-center distance?
antialias_physorg
not rated yet Jul 23, 2018
So what's the center-to-center distance?

You can approximate it by assuming these are two touching spheres. But for the speed the center to center distance is irrelevant because the interesting points (the fastest traveling points) are at the outer extremes.

For those doing the calcs here's a hint: They are moving not nearly as fast as one might think.

Link pls.

Oops, sorry
https://www.azom....eID=1114

From the density and size you can get the mass (approximating the dumbell shape as two spheres). From the mass and the angular velocity (which you get from the size and the number of revolutions per second (warning: the article gives revolutions per *minute*)) you can get the force (centrifugal force)...and from and taking the touching area into account you can compare to the tensile strength.
That should give you a function which tells you how fast this stuff would need to rotate before flying apart.

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