You’re familiar with the states of matter we encounter every day – such as solid, liquid and gas – but in more exotic and extreme conditions, new states can appear, and scientists in the US and China earlier this year A state has been achieved.
They’re calling it the chiral Bose-fluid state, and with every new arrangement of particles we discover, it can tell us more about the structure and mechanics of the universe around us – and in particular, super- On the small quantum scale.
States of matter describe how particles can interact with each other, creating different patterns of structures and behavior. Lock the atoms into place, and you have a solid. Let them flow, any liquid or gas you have. By separating the forced interactions, you have a plasma.
The quantum landscape offers even more strange ways for particles to interact, allowing unique behavior best described in terms of probability and energy.
Researchers discover new state through a frustrated quantum system. In simple terms, it is a system with built-in constraints that prevent particles from interacting normally (hence frustration).
These obstacles – and the resulting frustrations – can lead to exciting results for scientists. Here, the researchers focused on electrons and used the analogy of a party game to explain what was happening.
“It’s like a game of musical chairs, designed to decouple electrons,” said Tigran Sedrakyan, a theoretical condensed matter physicist at the University of Massachusetts Amherst.
“Instead of each electron having a chair to go to, they now have to scramble and have multiple possibilities as to where they sit.”
The system the researchers created was a semiconductor device with two layers: an upper layer that was rich in electrons and a lower layer that had many available holes for the electrons to naturally enter. twist? There are not enough holes for all the electrons.
Illustration of a trench band, the type of frustrated system created by scientists. (Tigran Sedrakyan)
Although such a system is difficult to observe, the team used an ultra-strong magnetic field to measure the motion of the electrons, revealing the first evidence of the new chiral Bose-liquid state.
“At the edge of a semiconductor bilayer, electrons and holes move with the same velocity,” said Lingji Du, a physicist at Nanjing University in China.
“This leads to helical-like transport, which can be further modified by external magnetic fields as the electron and hole channels gradually dissociate under high fields.”
This new state revealed some interesting properties. For example, electrons will settle into a predictable pattern and a fixed spin direction at absolute zero and cannot be interfered with by other particles or magnetic fields. That stability may have applications in quantum-level digital storage systems.
Furthermore, an external particle impacting one electron can impact all electrons in the system due to relatively long-range quantum entanglement. It’s like tossing a cue ball into a pack of billiard balls and in response all those balls travel in the same direction – another discovery that could be useful.
Although all this involves very high-level physics, each such discovery – these quirks and edge cases that lie outside the bounds of normal particle interactions – moves us closer to a full understanding of our world.
“You find quantum states of matter out at these edges, and they’re much wilder than the three classical states we encounter in our everyday lives,” Sedrakyan said.
Research has been published in Nature,
A version of this article was first published in June 2023.