This quantum physics experiment is bizarre. And at the same time, this is the most exciting thing we’ve seen

“If you think you understand quantum physics, you don’t really understand quantum physics.” We don’t say that. So says Richard Feynman, Nobel Prize winner in physics for his contributions to quantum electrodynamics and one of the most respected scientists of the 20th century. Quantum mechanics studies the laws that govern world of the very small, particles and interactions to which atomic and subatomic structures are subjected. And most of these rules are radically different from the laws we are familiar with in the world in which we live. In the macroscopic world.

Many physicists have spent the last century trying to understand how known quantum phenomena work, as well as trying to determine unknown quantum rules. The problem is that working with very small particles is very difficult. However, this does not mean that they are not successful. Advances come little by little, and one of them, the most recent, came from MIT (Massachusetts Institute of Technology) and has the potential to open the door wide to the exploration of exotic states of matter and the production of new quantum materials.

The Massachusetts Institute of Technology has managed to bring atoms much closer than was previously possible.

The interactions between atoms are much stronger when they are very close. The problem is that putting them together as needed is not easy. Physicists often solve this problem by cooling them until they reach such a low temperature that they almost stop completely. Once in this state, they use a laser to bring them closer until they are within 500 nanometers, a limit that is set by the wavelength of the laser light. This fact can help us put this figure in context: the width of a red blood cell is about 1000 nm.

What’s surprising is that a group of researchers from the Massachusetts Institute of Technology managed to break the 500 nanometer barrier. And the technology they’ve developed allows them to bring atoms closer to just 50 nanometers, a distance so tiny that it encourages emergence of new quantum effects as a consequence of interactions between atoms. It is curious that these physicists used dysprosium atoms in their experiment, since this chemical element has the highest magnetic moment at low temperature only after holmium.

In practice, MIT scientists cooled dysprosium atoms to temperatures close to absolute zero and spread them onto two very thin sheets using a laser so that the distance between both layers was only 50 nm. The amazing thing is that at this very short distance the magnetic interaction between dysprosium atoms is 1000 times more intense than at a wavelength of 500 nm, which, as I said above, leads to the emergence of new quantum effects. In fact, these physicists were able to measure two new effects caused by the proximity of atoms.

The first of these is known as “thermalization” and involves the transfer of thermal energy from one layer of dysprosium atoms to another. The second quantum effect manifests itself as a synchronized vibration of both layers of atoms. Interestingly, when the layers are separated, these two effects are weakened. until it completely disappears. Wolfgang Ketterle, a physics professor at the Massachusetts Institute of Technology who led the experiment, says his method can be used with other types of atoms to study the emergence of other quantum phenomena.

Everything we’ve seen so far is very interesting, but we’re missing something very important: knowing whether the experiment these physicists performed has any practical application. Fortunately, they are. Ketterle and his colleagues plan to use the technique they developed for this experiment to shape atoms into specific configurations that will allow them to build the first magnetic quantum gates. If they achieve their goal, they will strengthen the foundations of a new type of quantum computer. Let’s cross our fingers.

Image | Courtesy of the researchers (MIT)

Additional information | The science

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