You are familiar with the states of matter we encounter every day – such as solid, liquid and gas – but new states can arise in more exotic and extreme conditions, and scientists from the US and China have just found one.
They call it the chiral Bose fluid state, and as with any new arrangement of particles we discover, it can tell us more about the structure and mechanisms of the universe around us – and in particular about the supersmall quantum state. dish.
States of matter describe how particles can interact with each other, creating structures and different ways of behaving. Lock atoms in place and you have a solid. Let them flow, you have a liquid or gas. Force charged partnerships apart, you have a plasma.
The quantum landscape offers even weirder ways for particles to interact, enabling unique behaviors best described in terms of capabilities and energy.
Researchers discovered the new state through a frustrated quantum system. In simple terms, it’s a system with built-in constraints that prevent particles from interacting like normal (hence the frustration).
These limitations — and the resulting frustration — could yield exciting results for scientists. Here, the researchers focused on electrons and used the parlor game analogy to explain what happens.
“It’s like a game of musical chairs, designed to frustrate the electrons,” say theoretical condensed matter physicist Tigran Sedrakyan of the University of Massachusetts Amherst.
“Instead of each electron having one seat to go to, they now have to scramble and have a lot of possibilities where they sit.”
The system that researchers put together was a semiconductor device with two layers: an upper layer rich in electrons and a lower layer with many available holes for the electrons to move naturally. The twist? There are not enough holes for all the electrons.
While these types of systems remain difficult to observe, the team used an ultra-strong magnetic field to measure how the electrons moved, revealing the first evidence of the new chiral bose fluid state.
“At the edge of the semiconductor bilayer, electrons and holes move at the same speeds,” say physicist Lingjie Du of Nanjing University in China.
“This leads to helical transport, which can be further modulated by external magnetic fields as the electron and hole channels gradually separate under higher fields.”
This new state revealed some rather interesting features. For example, electrons will freeze to a predictable pattern and direction of rotation at absolute zero and cannot be disturbed by other particles or magnetic fields. That stability could have applications in quantum-level digital storage systems.
In addition, external particles that affect one electron can affect all electrons in the system, thanks to quantum entanglement over a relatively wide range. It’s like hitting a cue ball against a pack of billiard balls and all those balls moving in the same direction in response – another finding that could be useful.
While this is all about very high-level physics, every discovery like this — these quirks and edge cases that take place beyond the confines of ordinary particle interactions — brings us closer to a full understanding of our world.
“You find quantum states of matter far out at these edges, and they’re much wilder than the three classical states we encounter in our daily lives,” say Sedrakyan.
The research has been published in Nature.