A flock of birds can also be seen as a rupture of symmetry: instead of flying in random directions, they align like the rotation of a magnet. There is, however, an important difference: a ferromagnetic phase change is easily explained using statistical mechanics because it is a system of equilibrium.
But birds এবং and cells, bacteria, and traffic গাড়ি add new energy to the system. “Because they have internal energy sources, they behave differently,” Richard said. “And since they don’t save energy, as far as the system is concerned, it’s nowhere to be seen.”
Hanai and Littlewood began their investigation into the BEC phase transition, thinking of common, well-known phase transitions. Consider water: Although liquid water and steam look different, Littlewood said there is basically no symmetrical difference between them. Mathematically, at the point of transformation, the two states cannot be separated. In a system of equilibrium, that point is called a critical point.
Critical phenomena are seen everywhere – in cosmology, high-energy physics, and even in biological systems. But in all of these examples, researchers have not found a good model for condensates that are formed when quantum mechanical systems combine with the environment, through constant damping and pumping.
Hanai and Littlewood suspected that critical points and exceptional points need to share some important features, even if they are clearly derived from different processes. “Critical points are an interesting mathematical abstraction,” says Littlewood, “where you can’t tell the difference between these two stages. Exactly the same thing happens in this Polariton system.”
They also knew that under the mathematical hood, a laser প্রযুক্ত technically a state of matter এবং and a polariton এক্স exiton BEC একই had the same underlying equation. In a study published in 2019, researchers linked the dots, proposing a new and, importantly, universal approach by which the exceptional points give rise to phase transitions in quantum dynamic systems.
“We believe this was the first explanation for that transformation,” Hanai said.
Around the same time, Hanai said, they realized that although they were studying a quantum state of matter, their equations were not dependent on quantum mechanics. Does the phenomenon they were studying apply to larger and more common phenomena? “It simply came to our notice then [connecting a phase transition to an exceptional point] Can also be applied to classical systems. “
But to chase that idea, they will need help. They go to Vitali and Michelle Fruchart, postdoctoral researchers in Vitali’s lab, who study unusual symmetries in the classical realm. Their work extends into metamaterials, which are rich in interactions; They may, for example, react differently to pressure on one side or the other, and may even show exceptional points.
Vitelli and Fruchart were immediately intrigued. Were some universal policies effective in Polariton condensate, some basic rules about systems where energy is not stored?
Now in the fourteenth century, researchers are beginning to look for common principles based on the connection between dissociation and phase transition. For Vitelli, it means thinking with his hands. He has a habit of building physical and mechanical systems to depict difficult, abstract phenomena. In the past, for example, he has used lagos to create lettuce that has become a topological material that moves differently at the edges than at the interior.
“Even though what we’re talking about is theoretical, you can demonstrate it with toys,” he said.