A new state of matter in a one-dimensional quantum gas

As the story goes, the Greek mathematician Archimedes discovered an invention while traveling through ancient Egypt which later bore his name. It was a machine consisting of a screw inside a hollow tube that trapped and pulled water as it rotated. Now, researchers led by Stanford University physicist Benjamin Lev have developed a quantum version of the Archimedes screw that, instead of water, converts fragile groups of gas atoms to higher and higher energy states without collapsing. Their discovery is detailed in a paper published January 14 Science.

“I was expecting the stability of the gas to change a bit,” said Lev, an associate professor of applied physics and physics at Stanford University’s School of Humanities and Sciences. “I did not expect to see a complete, dramatic stabilization of it. It was beyond my wild imaginations.”

Along the way, the researchers also observed the development of stigmata – extremely rare pathways for particles in chaos Quantum system The particles retrace their steps as frequently as interfering with paths in a forest. Scar states are of particular interest because they may provide a sheltered haven for information encoded in a quantum system. The existence of scar cases within a quantum system with many interacting particles – known as the quantum multi-body system – was only recently confirmed. The Stanford experiment is the first example of a scar condition in many of the body Quantum gas And the second true vision of the phenomenon at all.

Super and stable

Leif specializes in experiments that expand our understanding of how different parts of a multi-body quantum system are stable at the same temperature or thermal equilibrium. This is an exciting field to investigate because resistance to so-called “thermal transfer” is key to creating stable quantum systems that can power new technologies, such as quantum computers.

In this experiment, the team discovered what would happen if they modified an experimental system unusual for many objects, called the Tonks-Girardeau super gas. These are highly excited, one-dimensional quantum gases – atoms in a gaseous state confined to a single line of motion – tuned in such a way that their atoms develop extremely strong attractive forces to each other. What’s cool about them is that, even under extreme forces, they should theoretically not collapse into a ball-like mass (like normal attractive gases). However, in practice, it collapses due to experimental defects. Lev, who is prone to the powerful magnetic element dysprosium, wondered what would happen if he and his students created a super-Tonks-Girardeau gas with dysprosium atoms and “completely” changed their magnetic orientations. Perhaps they will withstand collapse a little better than non-magnetic gases?

“The magnetic interactions that we were able to add were very weak compared to the attractive reactions already in the gas. So, our expectations were that it would not change much. We thought it would continue to collapse, but not quite easily.” Said Lev, who is also a member of Stanford Ginzton Lab and Q -FARM. “Wow, we were wrong.”

Their dysprosium contrast ended up producing the super-Tonix-Girardeau gas that remained stable regardless of the cause. The researchers flipped the atomic gas between attractive and disgusting conditions, raising or “tugging” the system to higher and higher energy states, but the atoms had not yet collapsed.

Build from the ground up

Although there are no immediate practical applications for their discovery, Leif’s lab and their colleagues are developing the science needed to power the quantum technology revolution many expect to come. For now, Lev said, the out-of-equilibrium physics of multi-body quantum systems remains constantly surprising.

He said, “There is no textbook yet on the shelf that you can pull off telling you how to build your own quantum plant.” “If you compare quantum science to what we were when we figured out what we need to know to build chemical plants, for example, it looks like we’re doing the work of the late nineteenth century right now.”

These researchers just started by examining the many questions they had about Archimedes’ quantum screw, including how to mathematically describe scar states and whether the system is heating up – and ultimately it should – how it is done. Immediately, they plan to measure the momentum of the atoms in scar states to begin developing a solid theory about why their system behaves the way it does.

The results of this experiment were so unpredictable that Lev says he cannot strongly predict the new knowledge that will come from a deeper examination of Archimedes’ quantum screw. But he suggests this is probably experimental at its best.

“This is one of the few times in my life where I actually worked on an experiment that was really experimental and not a presentation of the current theory. I didn’t know what the answer was beforehand,” said Lev. “Then we found something really new and unexpected that makes me say, ‘Yay Experiments! ”