Light is everywhere. Even the darkest of rooms in our homes contain a handful of blinking LEDs. But what is light? Few of us ever stop to think about this question. Around a hundred years ago scientists discovered that light comes in granules, much like the sand on a beach, which we now call photons.

These are truly bizarre objects that obey the rules of the quantum world. The rules allow some pairs of photons to share a property called entanglement. After being entangled, two photons behave as one object. Changing one photon will affect the other at exactly the same time, no matter how far apart they are.

Far from being a strange but useless property, this is now being put to good use to build computer networks that cannot be hacked. Imagine the scenario where you’re buying a gift over the internet. You will need to input your credit card details, hoping nobody steals them. But what happens if there is a smart criminal tapping your line, listening in to all your communications? Well, there is nothing stopping that eavesdropper from making off with your credit card details and using them on their next shopping spree.

With a quantum link, this will never happen. You would send one photon from an entangled pair to the web shop, keeping the other one yourself and using it to send your credit card details to the shop. Try as they might, ‘eavesdroppers’ would never be able to listen in to this conversation. This is because whenever they try to read the information you are sending to the shop, they will corrupt this information. The ‘eavesdropper’ will only read gibberish, and your secrets will remain safe.

Sounds like science fiction? Einstein thought so too, believing that entanglement was simply the result of an incompleteness in our quantum model. He argued that these effects would never be observed. Luckily, physicists persisted and we now know entanglement is real.

So how far off are scientists from delivering these quantum networks? Some banks in Europe already use them to communicate between branches. Scientists are still working on making it practical to install quantum networks in our homes. In a few years’ time we will all be able to relax in the knowledge that you can shop freely without compromising your credit card details.

Did you know…

• Every second around 100 lightning bolts strike the earth.

• A pure element can take many forms. For example, diamond and graphite are both forms of pure carbon.

• The seawater in the Mediterranean is changed only once every 2,000 years.

• Only five per cent of mating encounters between praying mantis leads to the male being devoured while copulating. The myth arises from stressful lab conditions that sees up to 50 per cent rates of male death during mating.

For more trivia: www.um.edu.mt/think

Sound bites

•A debate was recently held by the British Medical Journal on whether homeopathy should be recommended by doctors. Europe spends €1 billion on homeopathy, questioning whether this money could be better used elsewhere considering that no well-performed scientific experiments had proven its usefulness. It concluded that “it seems unreasonable, even unethical, for healthcare professionals to recommend its use”.

www.eurekalert.org/pub_releases/2015-07/b-sdr071015.php

•The wonder material graphene, which is stronger than steel and harder than diamond while conducting electricity, was found by researchers in Harvard to behave like water. Its electrons flowed like a fluid instead of a metal, possibly helping to explain phenomena like black holes.

www.sciencedaily.com/releases/2016/02/160211185926.htm

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