Researchers have devised a new method that allows them to generate quantum entanglement, the inexplicable linking up of two quantum particles, on demand.

Creating Quantum Entanglements

A team of quantum physicists at QuTech at the Delft University of Technology in the Netherlands has successfully produced quantum entanglements faster than the entanglement gets lost.

The researchers have developed a new method that allows them to create these entanglements so reliably that their most successful feat generated nearly 40 quantum entanglements at a distance of over 2 meters in a single second.

In a paper published in the journal Nature, the team led by QuTech's scientific director Ronald Hanson describes how their new feat could potentially pave the way to a slew of advanced applications, including an Internet protected by quantum encryption that is impossible for hackers to breach.

What Is Quantum Entanglement?

When it comes to science that boggles the mind, quantum entanglement is at the top of the list. Albert Einstein himself famously dismissed it by calling it "spooky action at a distance," yet quantum physicists of this day and age have proven over and over again that quantum entanglement is real.

Entanglement happens when very, very small particles become so connected to each other that whatever happens to one of them seemingly affects the other, even when they are separated by huge expanses of time and space. When researchers measure the state of one particle, they would be able to determine the state of its partner, even without having observed it at all.

However, what makes quantum entanglement so ridiculously stupefying that Einstein could not accept it is that quantum particles are always in a constant state of undecidedness until they are observed.

Following this notion, any given particle could be spinning clockwise or counterclockwise at once, like Schrödinger's infamous cat, until the particle is measured and "decides" to spin clockwise or counterclockwise.

With quantum entanglement, when one particle "decides" to spin clockwise, it is immediately known that the other spins counterclockwise.

The Entangled State

Researchers of the 21st century have not only proven Einstein wrong, they have also arrived at major breakthroughs in the weird and wacky science of quantum entanglement. Most recently, the team at Delft have been able to create quantum entanglements on demand using a new method based on existing experiments.

In 2015, Hanson and his team were able to demonstrate that "spooky action" was real by creating quantum entanglement between two photons placed 1.3 kilometers apart.

Here is how the method worked. The researchers used diamond crystals with an electron in an undecided state, meaning the electrons were positioned both up and down. They then shone a laser beam on the electrons, causing them to emit a photon, or a light particle, which is then entangled with the electron.

When the researchers combined each of the photons, both electrons became entangled with each other. The photons came together in a single wave and quantum entanglement became a success.

Unfortunately, external noise caused the entanglement to degrade rapidly in a fraction of a second. By building on this method, Hanson's team were able to create a more robust method that allowed them to generate entanglements on demand.

Quantum Entanglement On Demand

The researchers used an assembly line equipped with smart checks and balances that allowed them to make sure it was ready for entanglement. The result, says co-author Peter Humphreys, is a system that is a thousand times faster than the old method.

"Just like in the current internet, we always want to be online, the system has to entangle on each request," says Hanson.

On the assembly line, they were able to try and create entanglement a thousand times until they came up with the photon that spelled success. Next, they protected the entangled state from decaying by shielding it with gentle microwave pulses until delivery time, which was every tenth of a second.

Using this method, the team was able to generate 39 quantum entanglements, with decay happening only five times per second. By combining this result with an older experiment where they were able to protect the entangled state while producing a new entanglement, the researchers believe they could build a quantum network of computers with more than two connections.

"In 2020, we want to connect four cities in the Netherlands via quantum entanglement," Hanson says. "This will be the very first quantum internet in the world."

Photo: Gabriel Andrés Trujillo Escobedo | Flickr

ⓒ 2021 All rights reserved. Do not reproduce without permission.