A team of physicists at Brookhaven National Laboratory has managed to find a new way to use a particle collider to see the shape and details inside atomic nuclei. The new method, which has been applied in the RHIC (Relativistic Heavy Ion Collider), is based on the photons (particles of light) that surround gold ions as they move through the collider and on a new type of quantum entanglement. never observed so far.
The RHIC collider, which belongs to the United States Department of Energy (DOE) and which is installed in the same Brookhaven laboratory, makes it possible to study the most internal basic components of nuclear matter: the quarks and gluons that form protons and neutrons. Something that is achieved by colliding nuclei of heavy atoms, such as gold, that travel in opposite directions around the collider at close to the speed of light. Their intensity can ‘melt’ the boundaries between individual protons and neutrons so that scientists can study quarks and gluons as they existed in the early universe, before protons and neutrons formed.
Through a series of quantum fluctuations, the photons interact with gluons, the tiny particles that, like glue, hold together the quarks within the protons and neutrons that make up the atomic nucleus. Those interactions produce an intermediate particle, which rapidly decays into two ‘pions’ with different charges.
By measuring the speed and angles at which these particles (one positively charged and one negatively charged) hit RHIC’s STAR detector, scientists can go back to gain crucial information about the photon and use it to map the arrangement of gluons. within the core with the highest precision ever achieved. An unprecedented ‘peek’ into the depths of the atomic nuclei.
“This technique,” explains physicist James Daniel Brandenburg, a member of the collider’s STAR collaboration, “is similar to the way doctors use positron emission tomography (PET) to see what’s going on inside the brain and other parts of the body. . But in this case, we’re talking about mapping features on the scale of femtometers, quadrillionths of a meter, the size of an individual proton.”
A new kind of intertwining
But even more surprising, the scientists explain in an article published in ‘Science Advances’, is the observation of a completely new type of quantum entanglement that, among other things, has made their measurements possible. In the words of Zhangbu Xu, another of the STAR members, “we measured two outgoing particles and clearly their charges were different, that is, they were different particles, but we saw interference patterns that indicate that both were entangled or synchronized with each other, although the two were distinguishable particles.”
The finding, according to the researchers, may have implications that go far beyond ‘seeing’ the basic building blocks of matter. For example, the new type of entanglement could be used to create significantly more powerful computers and communication tools than exist today.
Indeed, for a long time, physicists have been looking for ways to take advantage of entanglement, a kind of instantaneous communication between physically separated particles, to create applications and devices that are beneficial to society. But so far, the vast majority of quantum entanglement observations have been made between identical photons or electrons. “This is the first experimental observation of entanglement – says Brandenburg – between different particles.”