Researchers at Caltech have succeeded in controlling both the motion of atoms and their internal energy – a first-of-its-kind achievement called “superentanglement,” which could accelerate the advancement of quantum technologies.
Prof. Manuel Andres, a physicist at Caltech, specializes in precisely controlling individual atoms using optical tweezers—laser beams that position and move atoms one by one. Using such arrays, Andres and his colleagues have been able to develop methods to erase errors in simple quantum machines, create extremely precise clocks, and control over 6,000 individual atoms—a world record.
In the new study, published in the journal Science, the team was able to exploit atomic motion – which is usually considered harmful noise – as a way to encode quantum information. “We show that atomic motion, which is usually considered unwanted noise, can be turned into an advantage,” explains Adam Shaw, co-author of the study along with Pascal Scholl and Ran Finkelstein.
Shaw was a student at Caltech and is now a postdoctoral researcher at Stanford. Scholl worked as a postdoctoral fellow at Caltech and now works at the French quantum company Pasqal. Finkelstein, who was a Troaches Fellow at Caltech, is now a professor at Tel Aviv University.
During the experiment, the researchers were able to encode quantum information in both the motion of the atoms and their electronic states – a condition called superentanglement. In normal entanglement, the states of two particles remain linked even when they are separated by a large distance. In superentanglement, two different properties of each pair of particles are linked – for example, both the motion and the internal energy.
The result: more quantum information in each individual atom – meaning higher efficiency. This is the first study to demonstrate superentanglement in particles with mass (and not just photons).
Another photo shows Adam Shaw, Ibeylo Madyarov, and Manuel Andres working on the optical system at Caltech laboratories.
The experiment involved cooling an array of neutral atoms from the base family inside optical tweezers. Using a unique method of "active detection and correction of thermal fluctuations," the researchers were able to cool the atoms to almost a complete standstill.
From there, they were made to oscillate quantumly – like a child swinging on a swing when both parents push them from both directions at the same time. The oscillators were put into a superposition state, where the atoms are in two states of motion at the same time.
Finally, entanglement between moving atoms led to superentanglement in which both the motion and the internal energy levels of the atoms were linked.
"The goal was to see how far we could push the ability to control atoms," says Anders. "Now we know how to control both the electrons and the external motion of the entire atom – as if you had an atomic toy that you completely controlled."
In conclusion, the researchers suggest that the motional states of atoms may in the future serve as an important resource in quantum technologies – from computing and simulations to precise measurements.
More of the topic in Hayadan:
