Physicists have observed a new state of matter at work within an elusive thread of quantum gas.
The gossamer gas jets that giants can bind sound like items worthy of a search in Grimms’ fairy tales. But versions of these materials are theoretically possible in physics – unfortunately in practice they inevitably collapse when forming.
Researchers at Stanford University in the US have now discovered that they can create such a material that is stable enough to withstand collapse in a cloud, even under considerable force. Plus, they’ve discovered a new state of matter at work that’s been seen only once before – and never before in quantum gas.
Importantly, the quantum properties of this gas can give it a place in future generations of information technology.
The matter at work category even has a legendary title; a super Tonks-Girardeau gas. It consists of atoms that have cooled to such an extent that they begin to lose their sense of individual identity, forced to form a conga line held in check by their collective forces.
Under ideal circumstances, the attraction between the particles in this drawn-out wire of quantum gas could even hold it in line under duress. That’s why physicists describe it as ‘super’.
But in imperfect laboratory equipment, even the most delicately tuned super Tonks-Girardeau gases do not remain stable for very long and contract into a ball in no time.
Physicist Benjamin Lev wondered if the element dysprosium would be a more robust candidate. With one of the highest magnetic strengths on the periodic table, it can last a little longer with a little support.
“The magnetic interactions that we were able to add were very weak compared to the attractive interactions already present in the gas. So our expectation was that not much would change,” says Lev.
“Wow, were we wrong.”
It turns out that a tuned super Tonks-Girardeau gas based on dysprosium is exactly what the hero ordered. Whatever the team did with it, it stayed in shape.
Even when put into higher energy states, the quantum system failed to push the wire into a messy haze of quantum smeared particles.
When the team examined the mechanics of the process, the team quickly noticed the features of a rather elusive phenomenon called quantum scars on many bodies.
This strange state lies somewhere between quantum chaos and the predictability of old-fashioned classical physics, and describes a world that at first glance seems counterintuitive.
A quarter of a century ago it was discovered that in the buzz of a quantum system – where particles are everywhere and nowhere at once and individual atoms lose their sense of self – it is possible for predictable states to arise.
These scars resemble trails worn across a soccer field. While players freely chase the ball all over the field, some directions seem to be preferable to others.
The amazing thing about quantum scars is how they fit with thermodynamics. Raise the temperature of a group of particles and they will just bounce around more and redistribute the heat energy until all bodies have roughly equal proportions.
Quantum scars on many bodies violate this equilibrium rule and favor some states no matter how much excitement grows around them.
The phenomenon has been seen before in a row of rubidium atoms, but never in a quantum gas. So finding signs of the state in a cooled series of dysprosium atoms can reveal a lot about how bodies in a quantum system share energy.
Since we are destined for a future full of quantum technologies, we will need to know as much as possible about how to remove heat from the computers of tomorrow.
But quantum scars on their own can be potentially useful for the storage of quantum information, or serve as a sort of simulator in the laboratory for studying quantum systems.
Aside from speculation about practical applications, Lev sees the work as fundamental to understanding the quantum landscape. Applications may come later.
“If you compare quantum science to where we were when we figured out what we needed to know to build chemical plants, for example, it’s like we’re doing the late 19th century work now,” says Lev.
A gas thread covered by quantum scars is just the beginning of a search for some truly amazing destinations.
This research is published in Science.