Strange behavior of sound through solids

Two sound waves (1 and 2) are produced, which propagate into two more sound waves (3 and 4), which are then detected. The probability of this process is described with a scattering amplitude of 4 points. Credit: Angelo Esposito

Not everything has to be seen to be believed; Some things are easily heard, such as a train approaching its station. In a recent research paper published in physical review messagesPutting their ears on the rods, the researchers discovered a new property of amplitude scattering based on their study of sound waves through a solid.

Whether it’s light or sound, physicists think of the probability of particle interactions (yes, sound can behave like a particle) in terms of probability curves or scattering amplitudes. It is a common belief that when the momentum or energy of one of the scattered particles goes to zero, the amplitudes of the scattering must always expand with the correct momentum forces (that is, p1s2s3, etc.). However, what the research team found is that Capacity It can be proportional to a fractional power (for example, p1/2s1/3s1/4etc.).

Why is this important? While quantum field theories, such as the Standard Model, allow researchers to make predictions about particle interactions with pinpoint accuracy, existing foundations of fundamental physics can still be improved. When a new behavior is introduced – such as the partial dynamometer – scientists are given an opportunity to reconsider or revise existing theories.

This work, conducted by Angelo Esposito (Institute for Advanced Study), Thomas Brauner (University of Stavanger), and Ricardo Pinco (Carnegie Mellon University), specifically takes into account the interactions of sound waves in solids. To visualize this concept, imagine a block of wood with speakers placed on either end. Once the speakers are turned on, two sound waves – phonons – meet each other and scatter, similar to collisions in a particle accelerator. When a single amplifier is set to a certain limit, so that the phonon momentum is zero, the resulting amplitude can be proportional to a fractional power. The team shows that this gradient behavior is likely not restricted to phonons in solids, and recognizing it may help study scattering amplitudes in many different contexts, from particle physics to cosmology.

“The detailed properties of the amplitude of the scattering have recently been studied very aggressively,” Esposito stated. “The goal of this broad program is to categorize potential patterns of scattering amplitude behavior, to make some of our calculations more efficient, and more ambitious, to build new foundations for quantum field theory.”

Feynman diagrams have always been an indispensable tool for particle physicists, but they come with some limitations. For example, high-precision calculations can require entering tens of thousands of Feynman diagrams into a computer, to describe particle interactions. By gaining a better understanding of the extent of scattering, researchers may be able to more easily determine the behavior of particles rather than relying on a top-down approach to Feynman diagrams, thus enhancing the efficiency of the computations.

“The present work reveals a twist in the story, as it shows that condensed matter physics exhibits much richer phenomena of scattering amplitude than previously seen in fundamental relativistic physics,” Esposito added. “The discovery of the fractal power meter calls for further work on scattering the amplitudes of the mass oscillations of matter, and putting solids in focus.”


Forging new paths in particle physics


more information:
Tomáš Brauner et al, Soft fractions of the amplitude of the scattering, physical review messages (2022). DOI: 10.1103/ PhysRevLett.128.231601

the quote: Strange Behavior of Sound through Solids (2022, September 12) Retrieved September 12, 2022 from

This document is subject to copyright. Notwithstanding any fair dealing for the purpose of private study or research, no part may be reproduced without written permission. The content is provided for informational purposes only.