Vanishing act: the Italian physicist Ettore Majorana, who disappeared in 1938. Photo: Kanijoman/Flickr
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The vanishing particle physicist and the puzzle he left behind

Ettore Majorana was an Italian physicist, the best of his generation, who disappeared in mysterious circumstances in 1938.

You probably haven’t heard of Majorana fermions. You probably haven’t heard of fermions, for that matter – nor of Ettore Majorana. Prepare yourself: it’s a story of mystery and frustration.

Let’s deal with the man first. Majorana was an Italian physicist, the best of his generation, who disappeared in mysterious circumstances in 1938. He emptied his bank account, bought a ticket for a boat ride from Palermo to Naples and left a note for his colleagues apologising for the inconvenience he was about to cause. He may have committed suicide but his body was never found. There are rumours of subsequent sightings in Buenos Aires. Some think that he abandoned physics and disappeared to live out his days in a secluded monastery.

Majorana’s specialism was quantum theory and it is tempting to think that he engineered his disappearance to reflect the subject’s strange ambiguities. A quantum particle such as an electron can be in two places at once, or simultaneously moving in two different directions; Majorana seemed to want his friends to wonder whether he could, too.

And so to his fermions. Just before his vanishing trick, Majorana predicted the existence of a particle with highly unusual properties. Although we have never seen one directly, there is every reason to think that it does exist and scientists on the 77-year-long hunt are tantalisingly close to pinning it down. This month, a group of Princeton University researchers added to the accumulating pile of evidence that the Majorana fermion is a real and fundamental building block of nature.

A fermion is one of the two types of particle that make up all matter. You have probably heard of the other one, the boson, because of all the Higgs fuss. Fermions are just as interesting. The building blocks of the atom – protons, neutrons and electrons – are all fermions. Majorana fermions have an added twist. Unlike protons, neutrons and electrons, they are their own antiparticle.

That is very odd. Matter and antimatter annihilate each other when they come into contact. Bang an electron and its antiparticle, the positron, together and they will disappear in a flash of energy. So how can a Majorana fermion be its own antiparticle?

To find out, we have to get one we can observe, hence the hunt. And in a peculiar case of life (or death) imitating art (or science), Majorana fermions are offering glimpses of their properties in materials crammed with ghostly particles that don’t actually exist.

When a solid conducts electricity, it does so because it contains negatively charged electrons that can move through the material. As they leave their usual position, the electrons leave behind a network of “holes”. Viewed from one perspective, these behave like real particles that have a charge opposite to the electron. The details get complicated but, in some materials, this can create a situation in which the moving charges and holes amount to something that behaves exactly like a Majorana fermion. That’s what the Princeton researchers have seen.

It has been very difficult to get this far. The material containing the Majorana fermion was just one atom wide and three atoms thick and had to be cooled to -272°C, one degree above the coldest temperature allowed by the laws of physics. The fermion was so small that it required a scanning-tunnelling microscope two storeys high to see it.

That said, although the observed particle is a good facsimile, it is frustratingly still more like a Majorana fermion’s shadow puppet than the real thing. Majorana’s legacy still eludes us. That note was not apologetic enough. 

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 22 October 2014 issue of the New Statesman, Why Britain and Germany aren't natural enemies

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The one where she turns into a USB stick: the worst uses of tech in films

The new film Worst Tinder Date Ever will join a long tradition of poorly-thought-through tech storylines.

News just in from Hollywood: someone is making a film about Tinder. What will they call it? Swipe Right, perhaps? I Super Like You? Some subtle allusion to the app’s small role in the plotline? Nope – according to Hollywood Reporterthe film has been christened Worst Tinder Date Ever.

With the exception of its heavily branded title (You’ve Got Gmail, anyone?), Worst Tinder Date Ever follows neatly in the tradition of writers manhandling tech into storylines. Because really, why does it matter if it was a Tinder date? This “rom com with action elements” reportedly focuses on the couple’s exploits after they meet on the app, so the dogged focus on it is presumably just a ploy to get millennial bums on cinema seats.  

Like the films on this list, it sounds like the tech in Worst Tinder Date Ever is just a byword for “modern and cool” – even as it demonstrates that the script is anything but.

Warning: spoilers ahead.

Lucy (2014)

Scarlett Johansson plays Lucy, a young woman who accidentally ingests large quantities of a new drug which promises to evolve your brain beyond normal human limits.

She evolves and evolves, gaining superhuman powers, until she hits peak human, and turns into first a supercomputer, and then a very long USB stick. USB-Lucy then texts Morgan Freeman's character on his fliphone to prove that: “I am everywhere.”

Beyond the obvious holes in this plotline (this wouldn’t happen if someone’s brain evolved; texting a phone is not a sign of omnipotence), USB sticks aren’t even that good – as Business Insider points out: “Flash drives are losing relevance because they can’t compete in speed and flexibility with cloud computing services . . . Flashdrives also can’t carry that much information.”

Star Wars: The Force Awakens (2015)

If you stare at it hard enough, the plotline in the latest Star Wars film boils down to the following: a gaggle of people travels across space in order to find a map showing Luke Skywalker’s location, held on a memory stick in a drawer in a spherical robot. Yep, those pesky flash drives again.

It later turns out that the map is incomplete, and the rest of it is in the hands of another robot, R2-D2, who won’t wake up for most of the film in order to spit out the missing fragment. Between them, creator George Lucas and writer and director JJ Abrams have dreamed up a dark vision of the future in which robots can talk and make decisions, but can’t email you a map.

Willy Wonka and the Chocolate Factory (1971)

In which a scientist uses a computer to find the “precise location of the three remaining golden tickets sent out into the world by Willy Wonka. When he asks it to spill the beans, it announces: “I won’t tell, that would be cheating.


Image: Paramount Pictures. 

The film inhabits a world where artificial intelligence has been achieved, but no one has thought to pull Charlie's poor grandparents out of extreme poverty, or design a computer with more than three buttons.

Independence Day (1996)

When an alien invasion threatens Earth, David Levinson (Jeff Goldblum) manages to stop it by hacking the alien spaceship and installing a virus. Using his Mac. Amazing, really, that aliens from across the universe would somehow use computing systems so similar to our own. 

Skyfall (2012)

In the Daniel Craig reboot of the series, MI6’s “Q” character (played by Ben Whishaw) becomes a computer expert, rather than just a gadget wizard. Unfortunately, this heralded some truly cringeworthy moments of “hacking” and “coding” in both Skyfall and Spectre (2014).

In the former, Bond and Q puzzle over a screen filled with a large, complex, web shape. They eventually realise it’s a map of subterranean London, but then the words security breach flash up, along with a skull. File under “films which make up their own operating systems because a command prompt box on a Windows desktop looks too boring”.

An honourable mention: Nelly and Kelly Rowland’s “Dilemma” (2009)

Not a movie, but how could we leave out a music video in which Kelly Rowland texts Nelly on a Microsoft Excel spreadsheet on a weird Nokia palm pilot?


Image: Vevo.

You’ll be waiting a long time for that response, Kelly. Try Tinder instead.

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