What could the NSA do with a quantum computer?

After many false starts it’s a research field that is just now coming of age - when harnessed, particles can perform staggeringly powerful computation.

The news that the US National Security Agency has been spying on public emails, phone calls and internet chat logs provokes an obvious question: just how much data can the NSA cope with? That depends on whether it has a working quantum computer.

A report leaked to the Guardian suggests that the NSA can get three billion pieces of information a month from computer records alone. Much has been made of how it would take ridiculous amounts of computer time to analyse it all. But that is exactly why the NSA, GCHQ and almost every other security agency in the world have spent the past two decades with one eye on a select group of physicists who could soon make the supercomputers of today look like children’s toys.

A standard “classical” computer stores information as a series of zeroes and ones on the microchips of its circuitry. A 0 is represented by the absence of electrical charge on a component called a capacitor. The presence of charges gives a 1. By moving the charges around between components in welldefined ways, you can represent any number you want and perform any computation.

The quantum computer uses a single atom or electron, rather than a bulky electrical charge, as the 0 or 1. In fact, the particle can be 0 and 1 at the same time. In certain conditions, atoms and subatomic particles can be in two places at once, or spin clockwise and anticlockwise at the same time. That means you can use a single atom to represent two binary digits.

Then there’s entanglement, another phenomenon of the subatomic world. This allows you to link many of the doubleheaded particles to create a string of binary digits that can simultaneously represent a huge array of numbers. A string of just 250 particles is enough to encode, simultaneously, more numbers than there are atoms in the known universe. Put those particles together in the form of a computer, and they can perform a staggeringly powerful computation on all these possible numbers at once.

So far, researchers have identified two applications for quantum computing. The first is a kind of reverse multiplication known as factorisation. This allows you to discover which numbers multiply each other to create any given number. It sounds trivial, but if the bigger number is big enough, no normal computer can do this in a reasonable time. The difficulty of factorisation is the mainstay of all data security, from military intelligence to financial transactions. So, a quantum computer is a game-changer.

The second application seems even more esoteric at first glance. It is a reverse telephonebook search: given a number, it can do the equivalent of finding a name, and much more quickly than any machine we have now. It is a way of sifting through unsorted data efficiently – just what the NSA needs.

And after many false starts it’s a research field that is just now coming of age. The first working, commercial quantum computer was created by DWave Systems, a firm based in Vancouver, Canada. Its first sale, in May 2011, was to the defence company Lockheed Martin, which has links with the NSA.

A major investor in D-Wave is In-Q-Tel, the business arm of the CIA, which “delivers innovative technology solutions in support of the missions of the US intelligence community”. IQT believes its customers can benefit from the promise of quantum computing because the intelligence world faces “many complex problems that tax classical computing”, according to Robert Ames, an IQT vice-president. He made that statement in September last year. Now we know just what he meant.

A new NSA data centre in Bluffdale, Utah. Photograph: Getty Images

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 24 June 2013 issue of the New Statesman, Mr Scotland

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“A cursed project”: a short history of the Facebook “like” button

Mark Zuckerberg didn't like it, it used to be called the “awesome button”, and FriendFeed got there first. 

The "like" button is perhaps the simplest of the website's features, but it's also come to define it. Companies vie for your thumbs up. Articles online contain little blue portals which send your likes back to Facebook. The action of "liking" something is seen to have such power that in 2010, a class action lawsuit was filed against Facebook claiming teenagers should not be able to "like" ads without parental consent. 

And today, Facebook begins trials of six new emoji reaction buttons which join the like button at the bottom of posts, multiplying its potential meanings by seven: 

All this makes it a little surprising that Facebook CEO Mark Zuckerberg spent a good portion of the noughties giving the like button a thumbs down. According to Andrew Bosworth, Vice President of Advertising and Pages at Facebook (and known simply as "Boz") it took nearly two years to get the concept of an approval button for posts off the ground.

In a fascinating Quora thread, Boz explains that the idea of a star, plus sign or thumbs up for posts first came up in July 2007, three years after "TheFacebook" launched in 2004. Throughout these initial discussions, the proposed bursts of positivity was referred to as an "awesome button". A few months later someone floated the word "like" as a replacement, but, according to Boz, it received a "lukewarm" reception. 

The team who ran the site's News Feed feature were keen, as it would help rank posts based on popularity. The ad team, meanwhile, thought "likes" could improve clickthrough rates on advertisements. But in November 2007, the engineering team presented the new feature to Mark Zuckerberg, and, according to Boz, the final review "[didn't] go well". The CEO was concerned about overshadowing the Facebook "share" and comment features - perhaps people would just "awesome" something, rather than re-posting the content or writing a message. He also wanted more clarification on whether others would see your feedback or not. After this meeting, Boz writes, "Feature development as originally envisioned basically stops". 

The teams who wanted the button forged ahead with slightly different features. If you were an early user, you might remember that News Feed items and ads collected positive or negative feedback from you, but this wasn't then displayed to other users. This feature was "ineffective", Boz writes, and was eventually shut down. 

So when Jonathan Piles, Jaren Morgenstern and designer Soleio took on the like button again in December 2008, many were skeptical: this was a "cursed project", and would never make it past a sceptical Zuckerberg. Their secret weapon, however was data scientist Itamar Rosenn, who provided data to show that a like button wouldn't reduce the number of comments on a post. - that, in fact, it increased the number of comments, as likes would boost a popular post up through the News Feed. Zuckerberg's fears that a lower-impact feedback style would discourage higher value interactions like reposting or commenting were shown to be unfounded. 

A bigger problem was that FriendFeed, a social aggregator site which shut down in April 2015, launched a "like" feature in October 2007, a fact which yielded some uncomfortable media coverage when Facebook's "like" finally launched. Yet Boz claims that no one at Facebook clocked onto FriendFeed's new feature: "As far as I can tell from my email archives, nobody at FB noticed. =/". 

Finally, on 9 February 2009, "like" launched with a blogpost, "I like this", from project manager Leah Pearlman who was there for the first "awesome button" discussions back in 2007. Her description of the button's purpose is a little curious, because it frames the feature as a kind of review: 

This is similar to how you might rate a restaurant on a reviews site. If you go to the restaurant and have a great time, you may want to rate it 5 stars. But if you had a particularly delicious dish there and want to rave about it, you can write a review detailing what you liked about the restaurant. We think of the new "Like" feature to be the stars, and the comments to be the review.

Yet as we all know, there's no room for negative reviews on Facebook - there is no dislike button, and there likely never will be. Even in the preliminary announcements about the new emoji reactions feature, Zuckerberg has repeatedly made clear that "dislike" is not a Facebook-worthy emotion: "We didn’t want to just build a Dislike button because we don’t want to turn Facebook into a forum where people are voting up or down on people’s posts. That doesn’t seem like the kind of community we want to create."

Thanks to the new buttons, you can be angry, excited, or in love with other people's content, but the one thing you can't do is disapprove of its existence. Championing positivity is all well and good, but Zuckerberg's love of the "like" has more to do with his users' psychology than it does a desire to make the world a happier place. Negative feedback drives users away, and thumbs-down discourages posting. A "dislike" button could slow the never-ending stream of News Feed content down to a trickle - and that, after all, is Facebook's worst nightmare. 

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.