Cats, computers and government surveillance

Last year I shared a stop-motion animation made using single trapped molecules by researchers at IBM.  I went on to briefly talk about the technique’s application in quantum computing, but in retrospect I don’t feel like I did the technology justice.  QC provides an enormous potential to scale down the size of computers, as I mentioned.  This, though, is only half the magic (because it is, basically, magic).  The reality-bending nature of quantum mechanics allows an object to be in more than one state at the same time (explanation of ‘state’ to come), which can cause some astounding things to be made possible.  A company called D-Wave who purport to be the world’s first and only quantum computing company (I say ‘purport’ as there’s a bit of controversy surrounding whether or not the computers they use are actually based on quantum mechanics) have produced their own video which explains the process quite well.  For my own explanation, I will invoke the (somewhat tired) analogy of Schrödinger’s Cat:

Schrödinger’s Cat is a thought experiment devised by the Austrian physicist after whom the experiment is named.  Our unfortunate feline finds itself trapped inside a sealed box, into which the outside observer has absolutely no way of observing.  Next to the cat is a single radioactive atom, a Geiger counter (which detects radiation) and a vial of poison.  Radioactivity is very much a statistical phenomenon – given a certain length of time, there is a certain probability the atom will ‘decay’ (and give out radiation) and a certain probability it won’t.  If the atom decays, the Geiger counter observes it, causing the vial to break.  The cat becomes, to use the wise words of John Cleese, an ex-cat.

Or does it? Quantum mechanics dictates to us that, whilst the box is closed and nobody can see inside, the cat is nether alive, nor dead, but a combination of both alive and dead – in what physicists call a ‘superposition state’.  It’s only when one opens the box and observes the cat that it is essentially forced into a state of either life or death.  Bizarre?  Well, if you’ve ever heard someone talking about the ‘strange nature’ of quantum mechanics, this thought experiment essentially underpins that strangeness.  When you get down to a quantum mechanical level, things just don’t behave the way you’d expect. For example, a single electron attached to the nucleus of an atom cannot be located to one single place, instead it has a ‘probability distribution’ – areas where it is likely to be, and areas where it isn’t likely to be.  It’s not until you actually try and observe this property (‘opening the box’) that it is forced to take a precise location.  The same goes for its speed – as it ‘orbits’ around the nucleus, it’s likely to be at a specific speed, though you can’t be sure, and the further away from that speed, the less likely it is. When you measure the speed, it takes a certain value.  This goes for just about every other parameter relating to the particle.

Now, I should state that in reality, were someone to be so ruthless as to actually do this to a cat (in the name of sciece!) then it would be plain old dead or alive, as we’d expect.  This non-intuitive behaviour only occurs at the quantum level, i.e. really, really, really small – so when an object is said to behave ‘quantum mechanically’, it’s generally something like a single particle.  In the (relatively enormous) biological system which constitutes a cat, the probabilistic nature (‘likely to do this, not likely to do that’) of a single (quantum-mechanical) particle is summed up over the vast number of particles, resulting in a life or death probability which is so enormously high that it’s vitually certain it’ll be either alive or dead.  By the same token, though, that means that quantum mechanically, virtually anything is possible (or, at the very least, it isn’t impossible).  To use an analogy by John Gribbin, if I’m looking at a granite statue, it’s not impossible that the atoms in its hand could suddenly rearrange themselves such that it appears to wave at me. Mind-boggling stuff.

Fundamental explanation of quantum mechanics aside, what’s so magic (I hope you now agree with me about the magic sentiment) about quantum computers?  Think, if you will, about the ‘bits’ (ones and zeroes) in your computer, each stored within a single capacitor.  Millions of these combined form data.  As I’ve previously mentioned, the QC uses the ‘qubit’ – similar to the bit, but far more useful.  This is because not only can the qubit store a zero or one (often, but not exclusively, via its spin-state), but also a superposition state between the two (as in the dead/alive quantum cat).  So now, where a classical computer is contrained to searching for individual combinations of zeroes and ones, its quantum equivalent can search through multiple combinations simultaneously.  Again, the video by D-Wave explains this quite well but you could maybe think of it in terms of coins.  If I have 10,000 coins in a row and am looking for a unique combination of heads and tails, as a classical computer I’d have to move all 10,000 coins into one composition; if that’s not the right one I’d have to move all 10,000 into another composition, and continue this process until I find the right setup.  As a shiny quantum computer though, I’d be able to look at multiple combinations at once – so I’d have multiple rows of 10,000 which I could move simultaneously.  The possible reductions in computation time are astronomical.

The scaled-down size and enormous speed allowed by this technology have huge potential implications.  It names quite a few in the video, though I particularly like the example given where a natural disaster has recently struck and the most efficient distribution of rescue resources has to be computed.  Such a huge number of alternative scenarios demands an enormous computing power, which only a QC could provide in a reasonable timeframe.  Huge numbers of lives could be saved.  One thing which did make me slightly uneasy, though, was the mention of the potential to sift through huge datasets ‘to catch bad guys’.  After everything we’ve heard about the misdeeds of various governments over the last couple of years I’m not sure I want GCHQ or the NSA to have that kind of snooping ability at their fingertips.  Perhaps if they were catching cat-killers my mind would be more at ease?


Don’t take it out on the tuna

I was recently confronted with this image on a social networking site:


Part of its tagline read “The medias [sic] latest distraction is working nicely. Meanwhile, our entire planet is flooding with extremely high levels of radiation and it keeps getting worse by the day. Something must be done.”

I have no problems agreeing with the sentiment of the statement about Miley Cyrus’s antics and their ability to captivate audiences.  Frivolous nonsense aside though, this is a deeply misleading image.  The dramatic colours permeating the Pacific supposedly represent  the extent of radioactive material leakage from the Fukushima nuclear power facility in Japan.

You may be inclined to think, that’s a lot of radioactive stuff, and it’s gone very far.  For half a moment I did.  Then I remembered not to blindly believe the message being portrayed, and looked more deeply into it…  Hang about, that scale is in centimetres – a unit of length, not radioactivity.

That’s because this map has nothing to do with radioactive leakage – it doesn’t even have any direct relation to Fukushima.  It’s the projection onto a 2D map of this image from the US National Oceanic and Atmospheric Administration, showing the 2011 tsunami’s maximum wave height.

I’m curious as to whether or not the person who produced this drivel knew the mistake they were making.  If I had to guess, it would be no – I can easily imagine someone involuntarily spitting their organic antioxidant-rich superfood cereal bar over their laptop after having googled ‘Fukushima’ and seen this, then feeling duty-bound to share it with the world.  Dishonest intentions or not, when faced with an image like this it’s easy to come to one’s own conclusions a little quicker than one should.

Unfortunately, discussion about Fukushima is littered with this kind of fear-mongering.  Take for instance the headline-grabbing reports about radioactive fish near Fukushima waters.  Many west-coast Americans are now afraid to eat tuna caught in the Pacific for fear they’ll grow another limb if they do.  The situation is explained perfectly here; what none of these reports tell you is that elevated levels of radioisotopes by no means necessarily constitute hazardous levels of radioisotopes.

You may also have read about the ‘300 tonnes of radioactive water’ leaking into the Pacific every day since the crisis.  Judging by the vastly-conflicting media reports I personally think that number is a little dubious.  Nonetheless, it does sound like a lot – to use the classic unit favoured by journalists the world over, that’s a 2-metre deep Olympic pool every 8 days.  It’s important to get a perspective on the scale of dilution going on here though.  1OP emptying into the Pacific Ocean, which has a volume of 6.6×10^17 m^3 (cheers Wolfram), every 8 days, for 2.5 years, represents 0.0000000004% of the ocean’s content originating from the site.  Ok, this is very much a ballpark figure, and that water is nowhere near evenly-distributed throughout the ocean, but hopefully it gives you an idea of how long it would actually take for the ocean to have any meaningful content of radioactive material.

The problem the nuclear industry has where public opinion is concerned is that so many people hold irrational opinions about the risk of radiation.  It’s important to remember that we come into contact with it every day.  Walls, food, even people have a small level of radioactivity.  The xkcd comic-writers have wonderfully illustrated this with a radiation dose chart which worth bearing a look at. Aside from the Olympic Pool, one of my favourite units is the Banana Equivalent Dose.  The average banana has an activity of roughly 15 Becquerels (15Bq), i.e. every second around 15 potassium-40 nuclei in your lunchbox decay, producing radiation (this isn’t quite the same as a BED, which takes into account the source and way in which the radiation is absorbed by the body).

Some figures released by Tepco in August show that there are 50,000-80,000 Bq (roughly 3000-5000 bananas) per cubic centimetre in the highly contaminated water collecting in the basements of the facility.  This is collected and treated, though it’s thought a lot leaks into the ground. Post-treatment, the water has levels of activity which are orders of magnitude lower. That which makes it into the groundwater contributes to the aforementioned ‘300 tons per day’, though again my dilution point applies: Put a litre (or 300 tons, you choose) of highly-radioactive water into an ocean of clean water, and you’ll get… an ocean of clean water (or, a negligibly differing amount of radioactivity, if you understand the concept of negligible).

Also, what none of the fact-scarce media reports have pointed out is that nearly 100% of the radiation detected at on-site storage leaks is beta radiation.  If you’ll cast your mind back to GCSE Physics, beta radiation is the emission of a single electron, and is absorbed by say, a sheet of paper, or two metres of air.  It is nearly impossible for a beta-emitter to cause a lethal dose in a human, no matter how strong, unless it is ingested.

Some of the more absurd claims about How Much Danger You’re In tend to come from websites such as ‘’ and ‘’, with the former enlightening us all with ‘11 facts about the ongoing Fukushima nuclear holocaust that are almost too horrifying to believe’.  Amongst this reputable list you’ll find truths such as ‘Something is causing fish along the west coast of Canada to bleed from their gills, bellies and eyeballs.  Could Fukushima be responsible?’ (no), or ‘150 former sailors and Marines say that they now have radiation sickness as a result of serving on U.S. Navy ships near Fukushima and they are suing for damages.’

To conclude, the point of my post is this: You are not in danger because of Fukushima.  Do not let anyone tell you otherwise, and treat misinformed media reports (even mainstream ones), with a healthy dose of scepticism.

A Boy And His Quantum Computer

I just wanted to take a minute from dissertation-writing to share this:

If you aren’t astounded, you should watch it again. Those are single carbon monoxide molecules – if you laid a thousand frames of the film side-by-side, you’d have something about as wide as a human hair. You might not find this stuff as exciting as I do, but I assure you that this kind of thing is going to be big in the coming decades (single trapped atoms that is, not stop-motion animation).

Trapped particles (like the atoms in the video) can potentially form the foundation of the quantum computer. The ‘building block’ of a modern computer is a transistor – a piece of semiconducting material around 50 nanometres across; roughly 500 times bigger than an atom. Transistors store the ‘bits’ in the computer with which you are currently reading this – they can either store 0, or 1. About 8000 of these transistors store one kilobyte’s worth of information, so say about 20 to 30 million will store one MP3 track.

Research centres like IBM and scores of academic institutions are working on taking the role of the transistor and implementing it into single atoms, or qubits – using their ‘quantum states’ to store the 0 or 1. As you might imagine, it isn’t easy (a ‘bit’ of an understatement – weeeeey), but if they can achieve it it’ll provide the means to scale the size of computer chips down by at least 100x. I’ll leave it to you to think of the potential applications.