The World's Smallest Engine Runs on a Single Atom

[n2doc]

Like the one in your car, Johannes Roßnagel's engine is a four-stroke. In four steps it compresses and heats, then expands and cools. And as with any other engine, this cycle is repeated over and over again—transforming the changing temperature into mechanical energy.

But Roßnagel's engine is no V-8. And it doesn't use internal combustion. Roßnagel, an experimental physicist at the University of Mainz in Germany, has conceived of and is in the process of building the world's tiniest engine, less than a micrometer in length. It is a machine so small it runs on a single atom. And in a recent paper in the journal Physical Review Letters, its inventors argue that, because of an interesting anomaly of quantum physics, this is also far and away the most efficient engine.

The nano engine works like this: First, using tiny electrodes, the physicists trap a single atom in a cone of electromagnetic energy. "We're using a calcium-40 ion," Roßnagel says, "but in principle the engine could be built with just about any ion at all." This electromagnetic cone is essentially the engine's housing, and squeezes tightly over the atom. The physicists then focus two lasers on each end of the cone: one at the pointy end, which heats the atom, and another at the base of the cone, which uses a process called Doppler cooling to cool the atom back down.

Because this heating and cooling slightly changes the size of the atom (more exactly, it alters the fuzzy smear of probability of where the atom exists), and the cone fits the atom so snuggly, the temperature change forces the atom to race back and forth along the length of the cone as the atom expands and contracts. For maximum efficiency, the physicists set the lasers to heat and cool at the same resonance at which the atom naturally vibrates from side to side.

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[Scuba]

1. And what does one power with the world's smallest engine? A teabaggers brain?

[notemason]

2. Congress

[marble falls]

11. <snicker>

[NRaleighLiberal]

3. calling Heisenberg! "alters the fuzzy smear of probability of where the atom exists"

[Richardo]

4. I guess the question is: can it generate more energy than it takes the lasers to power it?

Pretty cool in any case.

[wercal]

6. The answer to that would be a definite no....law of conservation of energy

But this miniature engine could do some amazing things. I'm thinking use in surgery where a very tiny hole is drilled in the body, and a nano engine like this, powered by a beam of laser light shining down the hole, can do surgical tasks.

[Richardo]

7. Good point - what I meant to get to was possible applications...

...which you've also addressed.

[dipsydoodle]

5. But if it was fitted in a car

would the car have cup holders ?

[Sentath]

9. I say Yes! And, better yet

You wouldn't have to worry about drinking and driving or open container laws.

Cause there's no way one of these.



is going to fit into a cup holder sized for just one of these

[marble falls]

12. Yes. Atomic ones. Like my Chevy.

[packman]

8. The ATOM says

.................. I LIKE IT

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But, I am confused, if the lasers set the atom in motion, does it continue in motion without the aid of continued laser bombardment? If not isn't this a form of perpetual motion and violates a law of physics? From my understanding of basic thermodynamics, seems inherently impossible without a continued outside energy support.

[Sentath]

10. Yeah, the title is a little confusing.

The calcium atom is more like a piston. The light is fuel.

[tclambert]

13. It's very efficient, but it takes forever to go from 0 to 60 mph.

[OxQQme]

14. OMG! What if the throttle stuck? n/t