Quantum entanglement discovery could enable novel comms tech The Register

In his cult classic “Ender’s Game”, Orson Scott Card imagined a world in which Earth’s brightest, and tragically youngest, tacticians could command armies across vast distances instantaneously using a device called the ansible.

While the jury is still out on whether such a device will ever be possible, scientists at the US Department of Energy’s (DoE) Brookhaven National Laboratory this week detailed a “never-before-seen” type of quantum entanglement they say could one day enable powerful new communications tools and computers.

Scientists have been trying to harness quantum-entangled particles ever since the phenomenon was theorized in the early 20th century and the topic has been a source of heated debate among physicists for decades. However, late last year, three scientists — Alain Aspect, John Clauser, and Anton Zeilinger — were awarded the Nobel Prize in Physics for their work on quantum entanglement.

A ‘new’ kind of quantum entanglement

Brookhaven’s latest discovery was made while exploring a novel means of probing the inner workings of atomic nuclei. The experiments, described in the journal Science Advances, used Brookhaven’s Relativistic Heavy Ion Collider to accelerate particles at nearly the speed of light.

Usually, the collider would smash the gold particles together. This would melt the boundaries between protons and neutrons and allow scientists to study the quarks and gluons — two of the elementary particles that form the nucleus of atoms — in an environment similar to that of the earliest moments of the galaxy.

But instead of smashing them together, the gold particles were surrounded by a cloud of photons and allowed to pass by each other.

According to Brookhaven, as they passed each other, a series of quantum fluctuations caused by the interaction between photons and gluons produced a new particle that quickly decayed into a pair of charged pions. When measured, these pions allowed scientists to map the distributions of gluons within the atom’s nucleus.

In a blog post, Daniel Brandenburg, a member of the STAR collaboration who worked on the project, said the technique works a bit like a scan at a doctor’s office, but instead of seeing inside a patient’s brain, scientists are peering into the inner workings of protons.

It was while taking these measurements that scientists say they observed a curious phenomenon — a new kind of quantum interference.

“We measure two outgoing particles and clearly their charges are different — they are different particles — but we see interference patterns that indicate these particles are entangled or in sync with one another, even though they are distinguishable particles,” Zhangbu Xu, a physicist at Brookhaven National Labs said in the blog post.

According to Brookhaven, most other observations of entanglement have been between photons or identical electrons. “This is the first-ever experimental observation of entanglement between dissimilar particles,” Brandenburg claims.

What are the Russians looking for?

Brookhaven was one of three DoE national labs targeted by Russian hackers over the summer.

According to Reuters, between August and September, a group of cybercriminals known as Cold River used phishing emails and fabricated log-in pages to harvest employee credentials from Brookhaven, Argonne, and Lawrence Livermore National Laboratories.

The facilities are home to a variety of nuclear research programs including several related to the maintenance and development of the US strategic stockpile.

While Reuters was able to confirm Cold River’s involvement with the help of five cybersecurity experts using digital fingerprints associated with the group, it was unable to determine whether the hackers were able to breach the DoE’s defenses.

Cold River has had previous success compromising high-profile targets. One of the group’s more recent targets was Richard Dearlove, the former head of Britain’s foreign intelligence service MI6, whose emails were leaked in May.

A prelude to the quantum internet

The DoE’s various national labs have been digging into quantum mechanics including practical applications of quantum entanglement for years now and has invested millions of dollars into the development of the quantum internet.

While no ansible, quantum networks take advantage of properties of particles to encode data more efficiently than is possible using the binary ones and zeros used in traditional computing. At least that’s the idea, anyway.

While efforts to build quantum networks are still in their infancy, several experiments have shown promise. In 2019, Brookhaven demonstrated the transfer of entangled photons over a fiber network stretching approximately 11 miles. At the time, it was the longest-distance quantum entanglement experiment to take place in the US.

More recently, researchers in the Netherlands showed the transmission of quantum information using an intermediary node, a feature they say is essential to enabling the quantum internet. ®