Quantum physicists just smashed the entanglement record, paving the way for faster quantum computers

Emma Sims April 17, 2018

Scientists in Germany and Austria have just made an enormous breakthrough in the field of quantum computing.

Quantum physicists just smashed the entanglement record, paving the way for faster quantum computers

Using a record system of 20 quantum bits, physicists have achieved a new entanglement record: the largest entangled quantum register of individually controllable systems in history.

For those left scratching their heads, you’re certainly not alone. Quantum computing’s main divergence from traditional computing is the way information is stored: one ‘unit’ can hold far more information than its classical counterpart. Quantum computers are also faster and more secure than the computers you and I are acquainted with, and entanglement is central to the development of such computers.

READ NEXT: What is quantum computing?

What is quantum entanglement?

In quantum physics, “entangled” particles are connected to each other meaning that any action performed on one particle affects the behaviour of the other, even if they’re separated by vast distances. If, for example, you measure the “up” spin of a photon in an entangled pair, the spin of the other will measure as “down”.

Albert Einstein called entanglement “spooky action at a distance” and he had trouble reconciling the theory as it suggests information between the two particles can travel faster than the time it takes for light to pass from one particle to another.

Being able to pass information between entangled photons quickly and efficiently is the key to developing faster quantum computers; the more entangled particles being added to the mix, the more information can be processed.

Quantum entanglement breakthrough

The team, led by Ben Lanyon and Rainer Blatt at the Institute of Quantum Optics and Quantum Information (IQOQI) at the Austrian Academy of Sciences, enlisted the help of theoretical physicists from the University of Ulm and the Institute of Quantum Optics.

As a collective, the researchers achieved a “controlled multi-particle engagement” in a record system of 20 quantum bits. Neighbouring groups of three, four and five quantum bits were found to be entangled in a way that had not been seen at such levels before.

In particular, scientists used laser light to entangle 20 calcium atoms, a controlled undertaking which took place in an ion trap experiment.

“The particles are first entangled in pairs,” explains Lanyon. “With the methods developed by our colleagues in Vienna and Ulm, we can then prove the further spread of the entanglement to all neighbouring particle triplets, most quadruplets and a few quintuplets.”

This is not a wholly new phenomenon. For years, physicists have been toying with entangled systems (the word “toying” here used very loosely). In fact, seven years ago, Blatt’s research group at the Institute of Experimental Physics at the University of Innsbruck successfully entangled 14 individual quantum bits for the first time, achieving the largest genuinely entangled quantum register.

While this all sounds cool, it truly comes into its own when given a practical application. The Innsbruck experiment, as it has become known, “was able to address and read out every single quantum bit individually”, explains study author Nicolai Friss. This makes it a viable option for things like quantum information processing, or quantum simulations. It could help to revolutionise the quantum computing industry, making computers immeasurably faster and more energy efficient than the ones we know today.

Rather than bask in their recent successes, the team is looking ahead to bigger, brighter and brainier things. “Our medium-term goal is 50 particles,” comes the response from Blatt. “This could help us solve problems that the best supercomputers today still fail to accomplish.” Child’s play, really.

Header image: IQOQI Innsbruck