Atoms star in world's smallest movie from IBM | Hacker News Reader

Atoms star in world's smallest movie from IBM

bbc.co.uk

92 pointsT-zex23 comments

The thing I find most fascinating about tunnelling electron microscopes is those "ripples" you can see around the atoms. Because of the tunnelling effect that those microscopes rely on, they're actual manifestations of the electrons' quantum mechanical wavefunctions; the complex waves of pure probability that are - when you get right down to it - the best answer to the question "what is an electron made of?" Ripples in probability and a few associated numbers like mass, charge and spin; that's it. Nothing more. And you can actually see it in the video.

Very, very cool.

Yeah, I was going to ask what those were.

If that's the case, it was interesting to me that the waves appeared to manifest a bit like a standing wave, with regularly repeating, equally distanced, higher and lower probability/amplitude propagating away from the atomic groups.

If that's correct, and electron probability wave functions mimic a standing wave, do different atoms have different standing wave frequencies? Does the resonance between different elements create any physical properties or predict anything...like what elements are likely to form a compound or the physical property of a compound?

Yes, great insight! One of the reasons quantum mechanics is "quantized" (which means limited to certain discrete values instead of being continuous) is that standing waves are reinforced as particles move around. For example, the rotational frequency/energy of an electron is limited to integer multiples of the circumference of the orbit. The "particle-in-a-box" model is the name of this quantum model. https://en.wikipedia.org/wiki/Particle_in_a_box

ah, so is what we're seeing in some sense the energy state of the electron? Or is it some probability function of what state the electron might be in?

I'm mentally trying to connect this image to modes of a vibrating string [1]

1 - http://hyperphysics.phy-astr.gsu.edu/hbase/waves/imgwav/strh...

"The device works by passing an electrically charged, phenomenally sharp metal needle across the surface of a sample. As the tip nears features on the surface, the charge can "jump the gap" in a quantum physics effect called tunnelling." So the image is a map of the probability that an electron will jump from the scanner to the surface! Check out the "quantum corral" at the bottom of this page http://education.mrsec.wisc.edu/Edetc/background/STM/

wild, thanks so much for the explanation and great links!

With regard to what actually is there: You may find Edward Fredkin's[1] work on digital physics[2],[3] interesting.

[1]: http://en.wikipedia.org/wiki/Edward_Fredkin

[2]: http://www.digitalphilosophy.org.

[3]: http://busyboxes.org/

Once you can manipulate atoms directly, I wonder why you couldn't create any of the following:

- Tiny self-replicating machines which produce other things to atomic precision? i.e. Nanobots... which could in turn create:

- "Surfaces" with "unimaginably high" surface area (due to the fractal arrangement of atomic height on the surface)

- "Solids" made out of dense things like 'iron' or 'carbon' and which have a volume but hardly any mass because there are so many holes (e.g. a 3D sierpinksi triangle)

... just 'data storage' seems the least exciting application (but then probably I'm misunderstanding some limitation...)

I'm inspired by this video: http://vimeo.com/63469979

It's pretty much moving atoms in two-dimensions only (essentially pushing them on a surface with a tiny needle). And it's painstaking--you certainly couldn't make anything on the macroscopic scale. I doubt even nanobots are feasible (how would they work?).

Also, in the case of e.g. the 3D Sierpinksi triangle there'd be structural issues (the voids would be fill with something), and you'd be up against entropy (there would be defects, so I'm not sure if it wouldn't just collapse) so it's really not much more than a thought experiment at this time. And, ultimately, what would be the point? Unless you can get novel electronic or mechanical effects etc. I'm not sure it'd be worth it.

We basically have nanobot's. The problem is unlike science fiction working at the atomic scale things don't react the same way. For example you can build a motor, but ATP or something close it it's going to be the fuel as heat engines don't really work. Which is why we end up using Bactria/viruses/plants/animals and simply overwrite their DNA. Granted we can get a lot better but don't expect anything to be both small and intelligent even the simplest chip is huge we compared to a virus.

Insanely-high surface area materials exist, the best example I can think of is activated charcoal https://en.wikipedia.org/wiki/Activated_charcoal#Properties but batteries are using it too http://spectrum.ieee.org/nanoclast/semiconductors/nanotechno... "Solids" like you mention are aerogels https://en.wikipedia.org/wiki/Aerogel#Alumina and this new aerographite http://www.extremetech.com/extreme/133056-aerographite-six-t...

> Tiny self-replicating machines which produce other things to atomic precision

Don't expect it to happen soon - we can't even make big self-replicating machines yet.

We don't even know what machines would look like at such a small scale. Structures behave very differently than they do at human scale; fundamental components like ropes, gears and pulleys might not be possible.

And then there's the problem of programming these machines; you can't exactly put an AVR inside them.

I don't think there's any particular reason to believe that building a large self-replicating machine wouldn't be feasible with modern technology. It's just not useful or cheap, so nobody's done it. NASA studied the idea and I don't think they came up with anything too impossible about it:

http://en.wikipedia.org/wiki/Clanking_replicator

From-scratch nanoscale replicators are a whole other beast. However, I think we can say that we know what they would look like, as we have a ton of examples from the natural world. Building ones that do our bidding is a bit tougher, obviously.

A machine that could build faithful copies of itself using only materials from the natural environment (i.e. not this http://en.wikipedia.org/wiki/File:MolecubesInMotion.jpg) would be absolutely revolutionary and would essentially be a completely alien and artificial life (mutation not being especially difficult to include, and probably difficult to prevent). It would change the world, because once you have replication you can piggy back just about any other ability on top of it and do it on a massive scale, no matter how inefficient at the individual level.

I will gladly pay you $100 billion for a self-replicating machine.

Avogadro's number matters. At 100 atoms/sec, how long will it take to make something larger than a cubic millimeter?

That's where the nanobot idea would come in - divide and conquer <=> replicate and multiply? Somehow a single DNA strand turns into a 3 kg baby in 9 months... so maybe it's possible to make a tiny machine that makes some bigger tiny machines etc. etc.

That was awesome, thank you for this video. The demoscene is inspiring.

You might find this page interesting too - goes into some detail on how it works: http://inst.eecs.berkeley.edu/~cs184/sp12/assignments/Archiv...

I'm itching to go try writing one now...

The machine they used to do this weighs about two tons. I don't think there's any indication that being able to do this implies being able to build atomic-scale machines that can do the same thing.

I like this quote: "This isn't really about a particular scientific breakthrough. The movie is really a conversation-starter to get kids and other people talking about - and excited about - math, science and technology." Technology gets the momentum once it is demonstrated to be used in some fun or even crazy ways.

More atoms starring in movies by IBM (1977):

http://www.youtube.com/watch?v=0fKBhvDjuy0

It is incredible to think how we can control atoms so precisely! This shows how nascent this science is and we have to go a long way. Once precise nano-control becomes more widespread we will see a new wave of engineering delivering goods that we thought were possible only in movies. At very high storage densities everyone of us could carry the same amount of data that powers Google's search engines.

When everything starts to fall apart for your business model of milking your customers for all they're worth and outsourcing all you can to cheap countries, have Carrie Underwood sing and make geeky movies about boys playing with atoms.

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