Birds have a wide field of vision. However, when they fly in a flock, they only orient themselves in relation to the birds that are in front of them or to their sides.
When we run, for example, our feet push off the ground and it pushes us back with equal but opposite force. Birds, schools, bacteria, crowds of people and cells, on the other hand, do not obey the Newton’s third lawbecause the components of these systems respond to only part of their environment.
This makes the interaction one-way, meaning that “action equals reaction” ceases to apply.
In a new one, published this Friday in Nature Physicsresearchers described the dynamic system of a flock of birds using established methods, as if it were a reciprocal system, even though it was not.
The solution is to artificially place a fictitious bird in front of each real bird, aligned in the opposite direction.
“The team developed and validated a theory that makes much of what we teach our students applicable to non-reciprocal systems as well. These systems, in which Newton’s third law does not apply, can now finally be accurately described and accurately simulated,” explained the study’s lead author, Marin Bukov.
According to , the trick behind the new theory consists of creating a partner for each component of the system — a fictitious partner that does not exist in nature.
The introduction of auxiliary degrees of freedom is nothing new in physics. What is new is the fact that these facilitate the study of systems with non-reciprocal interactions.
On the one hand, this allows researchers to draw on the already established theoretical framework of many-body physics. On the other hand, it allows non-reciprocal systems to be simulated with greater precision.
Finally, these discoveries deepen the understanding of these processes, with this knowledge being the basis for future investigations.
