Christian Joachim (who shared the Foresight Nanotech Institute Feynman Prize in the Experimental category in 1997 and won in the Theoretical category in 2005) is heading a group of researchers working to bring about atomic-scale computing. ScienceDaily led us to this European Commission ICT Results feature “Computing in a molecule“, which describes their on-going efforts:
Over the last 60 years, ever-smaller generations of transistors have driven exponential growth in computing power. Could molecules, each turned into miniscule computer components, trigger even greater growth in computing over the next 60?
Atomic-scale computing, in which computer processes are carried out in a single molecule or using a surface atomic-scale circuit, holds vast promise for the microelectronics industry. It allows computers to continue to increase in processing power through the development of components in the nano- and pico scale. In theory, atomic-scale computing could put computers more powerful than today’s supercomputers in everyone’s pocket.
“Atomic-scale computing researchers today are in much the same position as transistor inventors were before 1947. No one knows where this will lead,” says Christian Joachim of the French National Scientific Research Centre’s (CNRS) Centre for Material Elaboration & Structural Studies (CEMES) in Toulouse, France.
Joachim, the head of the CEMES Nanoscience and Picotechnology Group (GNS), is currently coordinating a team of researchers from 15 academic and industrial research institutes in Europe whose groundbreaking work on developing a molecular replacement for transistors has brought the vision of atomic-scale computing a step closer to reality. Their efforts, a continuation of work that began in the 1990s, are today being funded by the European Union in the Pico-Inside project.…
Nanotechnology is about taking something and shrinking it to its smallest possible scale. It’s a top-down approach,” Joachim says. He and the Pico-Inside team are turning that upside down, starting from the atom, the molecule, and exploring if such a tiny bit of matter can be a logic gate, memory source, or more. “It is a bottom-up or, as we call it, ‘bottom-bottom’ approach because we do not want to reach the material scale,” he explains.
Joachim’s team has focused on taking one individual molecule and building up computer components, with the ultimate goal of hosting a logic gate in a single molecule.
How many atoms to build a computer?
“The question we have asked ourselves is how many atoms does it take to build a computer?” Joachim says. “That is something we cannot answer at present, but we are getting a better idea about it.”
The team has managed to design a simple logic gate with 30 atoms that perform the same task as 14 transistors, while also exploring the architecture, technology and chemistry needed to achieve computing inside a single molecule and to interconnect molecules.
They are focusing on two architectures: one that mimics the classical design of a logic gate but in atomic form, including nodes, loops, meshes etc., and another, more complex, process that relies on changes to the molecule’s conformation to carry out the logic gate inputs and quantum mechanics to perform the computation.
The logic gates are interconnected using scanning-tunnelling microscopes and atomic-force microscopes — devices that can measure and move individual atoms with resolutions down to 1/100 of a nanometre (that is one hundred millionth of a millimetre!). As a side project, partly for fun but partly to stimulate new lines of research, Joachim and his team have used the technique to build tiny nano-machines, such as wheels, gears, motors and nano-vehicles each consisting of a single molecule.
“Put logic gates on it and it could decide where to go,” Joachim notes, pointing to what would be one of the world’s first implementations of atomic-scale robotics.
The importance of the Pico-Inside team’s work has been widely recognised in the scientific community, though Joachim cautions that it is still very much fundamental research. It will be some time before commercial applications emerge from it. However, emerge they all but certainly will.
—Jim
One of the main reasons that we are confident in the overall predictions of molecular manufacturing is that there are many pathways to it from current technology and using currently understood science. It is thus something of a milestone that we have arrived at a fork in the road about which there is room for disagreement about which path to take. The point at issue is diamondoid mechanosynthesis (DMS).
Eric Drexler has posted an essay in which he points out that he favors a pathway that leverages the capabilities of biochemistry and solution chemistry. He notes that he has always considered diamondoid mechanosynthesis a hard problem and a capability for advanced nanotech, not an early pathway.
Robert Freitas and Ralph Merkle are championing the direct DMS route. To extend the roadmap analogy, one could say that the solution-chemistry path is the long, winding river road and the DMS approach is the shortcut through the treacherous mountain passes.
Which is right? My own opinion is that this is the wrong question. There are many paths to productive nanosystems, and trying all of them is none too big an investment in our future. In the meantime, the more of a debate that develops between alternatives, the more the technical issues will be discussed and the more hitherto un-thought-of alternative pathways will be explored.
The first stage of the public conversation about a new technology, the debate is over whether heavier-than-air machines can fly. In the second stage, it’s over things like biplanes vs monoplanes.
Welcome to the second stage.
(Hat-tip to Next Big Future)
Nanowerk News reports that an international nanotech collaboration of American and Korean scientists, funded by the Korean government, has developed multifunctional gold-coated nanowires that are designed to swim through the blood stream and attach to cancerous cells via antibodies against the cancer cells. Exposure to an electromagnetic field should heat the nanowires and destroy the cancerous cells while sparing nearby normal cells. Unfortunately, the University of Idaho press release on which the story is based is light on technical details:
The next big thing in cancer treatment may be hotter, covered in more gold, and even be a better swimmer than recent Olympic champion Michael Phelps.
Scientists at the University of Idaho are engineering multifunctional and dynamic nanowires coated in gold that swim through the bloodstream and attach to specific cancerous cells. Once there, an electromagnetic field heats the nanowires, which destroys the targeted cells. The research is supported by a new $425,000 grant, part of a multimillion dollar project funded by the Korean government as part of the International Global Collaboration Pioneer Program.
“Cancer is a dangerous enemy because radiation and chemical treatments cause a lot of side effects,” said Daniel Choi, associate professor of materials science and engineering at the University of Idaho and leader of the project. “We can’t avoid side effects 100 percent, but these nanowires will minimize the damage to healthy cells.”
The technology involves many steps requiring lots of continuing research, but each of the basic concepts already have been proven in laboratory tests.
Choi and his team have already created nanowires that can “swim” to their targets and heat up when exposed to low frequency electromagnetic fields, which are not harmful to human body. The next step is to make them biocompatible, meaning safe to introduce to the human body, and able to seek out specific cancer cells.
Choi believes the gold plating will take care of the biocompatibility. If not, he has several polymers in mind that he also believes would work.
As for seeking out specific cancer cells, Choi also is a member of and working with a University of Idaho group called BANTech — an interdisciplinary group that integrates nanomaterials research with cell biology and bioscience research. The group has identified several promising candidates for antibodies with which to coat the nanowires that would seek out and attach to specific cancer cells.
Once the technology has proven itself in the laboratory, it will be tested in live animals, and eventually human beings. Several Korean institutions, which are helping in every phase of research, will take the lead in that project. The institutions are Seoul National University, Korea University and the Korea Institute of Science and Technology.
—Jim
A new nanotech method of DNA sequencing is 30,000 times faster than current DNA sequencing methods. The method, developed by a team at Pacific BioSciences in Menlo Park, California, uses a nanostructured array of thousands of waveguides—tiny hollow metal cylinders, each holding about a zeptoliter (10-21 liter)—to isolate a single molecule of DNA and a single molecule of DNA polymerase. Each of the four nucleotide bases is labeled with a different colored fluorescent label, with the fluorescent dye attached to the portion of the nucleotide that is cleaved and removed after the nucleotide is added to the growing DNA chain. As each nucleotide base is incorporated into the growing DNA chain within one waveguide, a spot of light of the corresponding color first appears, and then disappears. The sequence of flashes in each well reveals the DNA sequence copied in that well in real time. The array allows the simultaneous observation of thousands of single molecule DNA sequencing reactions. Preliminary experiments published in Science (abstract) report 100% accuracy with test DNA templates 150 bases in length. For more, see the article in NewScientist Tech written by Jessica Griggs: “Molecular fireworks could produce ‘30-minute genomes’” (thanks to KurzweilAI.net for the link):
So far, the team has built a chip housing 3000 ZMWs [waveguides], which the company hopes will hit the market in 2010. By 2013, it aims to squeeze a million ZMWs [waveguides] onto a single chip and observe DNA being assembled in each simultaneously. Company founder Stephen Turner estimates that such a chip would be able to sequence an entire human genome in under half an hour to 99.999 per cent accuracy for under $1000.
Griggs quotes an independent authority as being skeptical of the 2013 extrapolation. Even for such an elegant technique, it is a long jump from 150 to 3 billion bases.
—Jim
The following is an edited and revised version of the talk I gave at the Global Catastrophic Risks conference that was held in conjunction with Convergence 08 (and which I reprised for Convergence). I’m posting it here because it seems to me that this is exactly the kind of thing Foresight was founded for: to examine the revolutionary impacts of readily forseeable applications of nanotechnology.
In its present form, the Weather Machine is a work of futurism, not engineering. I have done only back-of-the-envelope calculations, and my assertions about what could be built are based more on instinct and educated guesses than on any major, deep engineering analysis. Even so, as a futurist I am fairly sure that something like the weather machine will be possible within the next few decades.
The Weather Machine, Mark I
Here’s the basic idea for the machine: construct a small aerostat—a hydrogen balloon—at a guess an optimal size is somewhere between a millimeter and a centimeter in diameter. It has a very thin shell of diamond, maybe just a nanometer thick. It’s round, and it has inside it (and possibly extending outside, giving it the shape of the planet Saturn) an equatorial plane that is a mirror. If you squashed it flat, you would have a disc only a few nanometers thick. Although you could build such a balloon out of materials that we build balloons of now, it would not be economical for our purposes. Given that we can build these aerostats so that the total amount of material in one is actually very, very small, we can inflate them with hydrogen in such a way that they will float at an altitude of twenty miles or so—well into the stratosphere and above the weather and the jet streams.
Each aerostat contains a mirror, and also a control unit consisting of a radio receiver, computer, and GPS receiver. It has just barely enough power and fans or other actuators to tilt itself to a preferred orientation. That’s all it does—listens for commands on the radio, and tilts to an angle that is a function of its latitude and longitude. It’s not really a complicated machine.
Now make enough of them to cover the entire globe. For the centimeter size, you’d need about five quintillion of them. This is why nanotechnology makes a big difference. If you tried to cover the earth with something the total thickness of even a current-day party balloon, let’s say about 100 microns, you need on the order of 100 billion tonnes of material, but with the nano-engineered design, just a few nanometers thick, you only need about ten million tonnes. To compare that with the scope of current-day construction, ten million tonnes is roughly the amount of material that is used to make a hundred miles of freeway. This is an amount of material that current-day technology, much less nanotech, can handle straightforwardly.
That’s the weather machine. We have these aerostats which float twenty miles up. They have GPS and controllers and can turn themselves. That’s all there is to it. What could you do with a machine like this? The machine is essentially a programmable greenhouse gas. If you set the mirrors facing the sun, it reflects all the sunlight back. If you set them sideways, it allows the sunlight to come through, and similarly for the longwave radiation coming from the back side of the earth at night.
For comparison, the radiative forcing associated with CO2 as a greenhouse gas, as generally mentioned in the theory of global warming, is on the order of one watt per square meter. The weather machine would allow direct control of a substantial fraction of the total insolation, on the order of a kilowatt per square meter—1000 times as much. It would completely trump any natural or anthropogenic climatic forcing, and allow us to set Earth’s climate to whatever we wanted it to be.
For mere overall climate control, we’d only need to build a few tenths of a percent of a full weather machine, and the controls on the individual aerostats can be very simple. When set to let sunlight through, for example, the mirrors can be several degrees away from edge-on to the sun, and the effect would be a scattering of light (visible perhaps as a slight haziness) but no significant reduction in total insolation.
Kardashev Type I civilization
A Kardashev Type I civilization is one that controls all the energy available on a single planet. A Weather Machine would do that—our total current energy (strictly speaking, power) use, at 15 terawatts, is a completely negligible fraction of the over 100 petawatts the machine would control.
If you read the IPCC numbers on how much global warming is going to cost, the actual estimate is that over the course of the century it is going to be about 3% of the global GDP—a huge sum of money. A Weather Machine could not only prevent that, but probably double the GDP simply by regional climate control. If you could actually control the climate and tailor it, you could make land in lots of places on the earth, such as Northern Canada and Russia, as valuable as California. The economic benefit would be enormous. There is a huge amount of value to being able to control the weather. This is something that people have always wanted to do and therefore, once it becomes possible, they probably will.
The better control we have over our aerostats, the more we can do. Controlling insolation on the scale of tens or hundreds of miles would probably give us the ability to affect daily weather patterns as well as climatic averages. Given really precise control, you could enhance solar power, for example. Build an array of photovoltaics in the desert and and then program about a thousand square kilometers of aerostats above it to focus the sunlight down onto your array. Instead of needing a thousand square kilometers of solar collectors, you need only one. The main reason solar power is expensive is that it’s diffuse, so the capital costs for collecting it are high. But with 1000x concentration it should be quite economical. The concentration is more or less free because you have already built the machine to control the weather. What’s more, you have not changed the energy balance any, because you are shading all the areas that are otherwise under the thousand square kilometers. That gives your concentrated collector, in broad daylight, an energy flux that is approximately the same as a thousand nuclear reactors of a typical size. Of course, you have to cool the collectors fairly vigorously because they are not 100% efficient.
In 2029 the asteroid Apophis is going to come within the orbit of the moon, passing the earth, in what will be something of a butterfly effect incident where it is fairly difficult to predict exactly what is going to happen to it after that close encounter. Apophis will return in 2036 and we can’t say for sure whether it will strike the Earth or not. In 2029, if a highly controllable Weather Machine had been built by then, as the asteroid comes tumbling past we could focus a few petawatts of sunlight on it and give it a kick. This is probably a lot more appropriate in the case of Apophis than many other asteroids because it is going to be so close. A small kick in 2029 will have a huge result in 2036, almost certainly enough to prevent a strike if that should actually be the trajectory it’s on.
The Weather Machine, Mark II
The Mark I Weather Machine is something like nanomechanical rod logic—an gedanken experiment existence proof that a given level of technology will have a given capability. We can go a bit farther and talk about what the capability might be like given closer control of light and matter, bearing in mind this is somewhat more speculative.
Take the same aerostat, but inside put an aerogel composed of electronically switchable optical-frequency antennas—these are beginning to be looked at in the labs now under the name of nantennas. We can now tune the aerostat to be an absorber or transmitter of radiation in any desired frequency, in any desired direction (and if we’re really good, with any desired phase). It’s all solid state, with no need to control the aerostat’s physical attitude. Once we have that, the Weather Machine essentially becomes an enormous directional video screen, or with phase control, hologram.
Astronomers hated Weather Machine Mark I, but they love Mark II because it turns the entire earth into a telescope with an aperture of 8,000 miles. Mark I could zap Apophis as it flew by inside the Moon’s orbit; Mark II could zap asteroids at much greater distances, or power laser-propulsion spacecraft.
Mark II, with the ability to shift frequencies and directions independently, is powered at night. Mark I could cool the Earth by shading the sunlight on the dayside, or warm it by reflecting back the infrared that pours into the night sky. The total power going in and out is roughly the same (although more goes out from the dayside for a variety of reasons). Thus there’s plenty of power available for the nightside to do street-lighting, or show ads in the sky, or whatever you’d like. Remember that because it’s a hologram, it can have a completely different effect for each spot on the surface: my night sky can be a giant telescope, and my neighbor’s can be a giant video game.
Coming soon to a planet near you
I’m fairly certain that a Weather machine will be built sometime this century. It seems straightforwardly within the capabilities of molecular manufacturing, particularly the Mark I form. There are plenty of people worried about things like climate change or asteroid impact that it could prevent or ameliorate. It could have an enormous economic value. All of these indicate that it should be built, but the most pressing and cogent reason that it will be is likely military.
Rremember the solar power plant. What if instead of a power plant beneath this thousand square kilometers of concentrated sunlight, there were an army, fleet, or indeed a city? Another way of specifying the amount of energy that would get pumped into the area is that it would be the equivalent of exploding a one-kiloton bomb every second for as long as you wanted. A Weather Machine would be a very potent weapon, even the Mark I version. Mark II could shoot down the moons of Mars.
Even without direct attacks, whoever can control the weather on Earth is pretty much in charge here. Anyone who objects and starts rattling their sabers gets twenty years of no summer and no growing season. For that reason alone, given the technological capability of doing it, it will be done. I cannot see the US government understanding that this is possible and not doing it. In fact, there are several other governments I cannot see understanding it can be done and not doing it.
If you are a smaller government without enough conventional forces to defend yourself well while your Weather Machine is being built, I would guess that approximately 5% of one is all you would need to have a setting that was a dead man switch: if someone came and blew you up and you quit sending out the control signals, all of the aerostats would default into snowball earth mode. It would be a doomsday device. This is troubling.
Once somebody gets 5% of one built, you’re stuck listening to them. You had better start building your own first, or at least simultaneously. In fact, it seems reasonable to imagine that by later in the century there are going to be several competing clouds of these things around. Hopefully they won’t end up physically competing with each other, but that the people in charge of them will come to some negotiation. That’s going to be all the more reason for someone wanting to be in the game. You have three quintillion balloons up, and I have one quintillion, and this guy over there has two quintillion, which means we get that many votes in the weather control world government.
The ultimate implications of a Weather Machine are mind-boggling. I can’t even come close to seeing all of the implications that it will have, but I’m fairly sure that it’s possible and that it will happen. It’s worth thinking about.
Random clumps and tangles of carbon nanotubes are of limited use, but a method of depositing dense arrays of highly aligned carbon nanotubes on either rigid or flexible substrates promises transparent nanotech transistors for a variety of electronic applications. From the University of Southern California, via AAAS EurekAlert “USC researchers print dense lattice of transparent nanotube transistors on flexible base“:
It’s a clear, colorless disk about 5 inches in diameter that bends and twists like a playing card, with a lattice of more than 20,000 nanotube transistors capable of high-performance electronics printed upon it using a potentially inexpensive low-temperature process.
Its University of Southern California creators believe the prototype points the way to such long sought after applications as affordable “head-up” car windshield displays. The lattices could also be used to create cheap, ultra thin, low-power “e-paper” displays.
They might even be incorporated into fabric that would change color or pattern as desired for clothing or even wall covering, into nametags, signage and other applications.
A team at the USC Viterbi School of Engineering created the new device, described and illustrated in a just-published paper on “Transparent Electronics Based on Printed Aligned Nanotubes on Rigid and Flexible Structures” in the journal ACS Nano [abstract].
Graduate students Fumiaki Ishikawa and Hsiaoh-Kang Chang worked under Professor Chongwu Zhou of the School’s Ming Hsieh Department of Electrical Engineering on the project, solving the problems of attaching dense matrices of carbon nanotubes not just to heat-resistant glass but also to flexible but highly heat-vulnerable transparent plastic substrates.
The researchers not only created printed circuit lattices of nanotube-based transistors to the transparent plastic but also additionally connected them to commercial gallium nitrate (GaN) light-emitting diodes, which change their luminosity by a factor of 1,000 as they are energized.
“Our results suggest that aligned nanotubes have great potential to work as building blocks for future transparent electronics,” say the researchers.
—Jim
A recent paper from Feynman Prize winner James Tour’s group at Rice
relates an interesting new form of memory based on a bistable 2-terminal
graphitic switch. Once developed, the switch could form the basis
of a high-density non-volatile storage which might replace flash devices
(which are already beginning to replace magnetic disks).
Rice press release
The way the device works is straightforward: put one volt across the
switch, and if it’s on, it will conduct several microamps; if it’s
off, it conducts a few picoamps, an easily-measurable factor of a
million (or more) difference. Put 6 volts across it, and it turns
off, as if you were blowing a fuse. But put 4 volts across it and
it turns back on again! The paper proposes that there is a physical
configuration change, and the device acts as an electrostatic relay.
The group did extensive testing on the devices and showed that they
are remarkably robust, operating for thousands of cycles at a wide
range of temperatures and even after having been zapped with x-rays.
The devices themselves are essentially just nanocables made by depositing
a layer of graphene on a SiO2 nanowire by CVD. The interesting point
is the switching behavior appears to occur at defects in the graphene;
if the wire is too perfect, it doesn’t work. Since the defect size
is comparable to the cable width, the entire active part of the switch
fits in a 100 nanometer cube or so.
How soon are we going to have these in our computers? It’s important
to understand the amount of development that has to be done between
any laboratory advance and commercialization. So note that the following
remarks apply to virtually every such promising development you hear
about:
- The devices are essentially made, or at least processed, by hand one
at a time - the lab work involved picking 35 working devices out
of 48. Commercialization would require some way of reliably making
billions of devices with properties similar enough that the same driving
voltages, sense amps, and other supporting circuitry could be used
for all of them.
- The physics are not completely understood. (For example,
a paper out of Bockrath’s group at Caltech
proposes a somewhat different mechanism for a similar switching behavior
in a non-nanocable graphene device.) This isn’t actually as important
as you might think, given that the useful behavior is robust and well-characterized.
But it would help with the ultimate reduction of the devices to the
lower limits of scale.
- Given a cheaply-manufacturable array of a billion perfectly-working
devices, you’d still have to develop the read-write circuits, interfaces,
packaging, standards, and so forth.
All of this takes time, not to mention the investment of substantial
development resources. A general rule of thumb is that from a lab
demonstration, even one as extensively tested and well-characterized
as this, expect a decade or so before you have it on your desk.
The long-term promise of this kind of discovery is that there are
structures accessible to current-day fabrication techniques such as
CVD which exhibit this switching/memory behavior at what is apparently
quite close to atomic scale. This can only improve (particularly in
density — probably approaching the 10-atom dimensions of the graphene layer)
as fabrication technology approaches and ultimately attains
atomic precision.
The Allen Institute for Brain Science is using nanotech methods to map in which cells in the brain which genes are expressed, which should lead to new insights into the relationships among genes, brain regions, behavior, and disease. Such knowledge might also advance the development of ‘cognitive computing‘—the effort to build computers that mimic brains. From Nano World News, “A high-throughput platform for nanoparticle-based multiplex in-situ hybridization in brain“, written by Z. Riley and A. Jeromin:
Zackery Riley, BSc, MBA, is a senior research associate in the Methods Development group at the Allen Institute for Brain Science. Andreas Jeromin, PhD, is currently the manager of the Methods Development group at the Allen Institute for Brain Science. Their interest is focused on the development of novel and improved gene expression platforms and their integration with other high-throughput technologies.
The Allen Brain Atlas, developed by the Allen Institute for Brain Science, is the first large-scale atlas of gene expression in the mouse brain, using chromogenic in situ hybridization (cISH) to detect the location of over 20,000 genes.
To overcome the limitations of a single label chromogenic cISH platform, Zack Riley, Emi Byrnes, Sheana Parry, Nick Dee and Andreas Jeromin developed a high-throughput multispectral quantum dot (Qdot) ISH platform (Fig 1). This new ISH tool provides a mechanism to systematically examine spatial gene expression patterns, aided by multispectral imaging, in the mouse and human brain.
The intrinsic photostability, brightness and tunability of Qdots is critical in providing superior signal-to-noise of the ISH signal and long-term stability, while minimizing photobleaching and allowing re-scanning of images. The photostability and tunability of the quantum dot nanocrystals is an ideal technology for examining localized and scattered gene expression in situ.
—Jim
