Smart design carries sound one way

July 17, 2017, Leiden Institute of Physics
Credit: Leiden Institute of Physics

A new computer simulation shows the promising possibilities of the booming field of topology. Smartly designed mechanical structures carry sound exclusively one way and are immune to fabrication errors. The study has been published in Nature Physics.

Imagine unboxing a freshly purchased headset only to find out that one earphone is slightly damaged. You have every right to send it back – after all, it will never as good as new. However, with the help of some fundamental , in the future it might be possible to create products that would carry sound perfectly even despite any manufacturing defects. The research group of Leiden physicist Vincenzo Vitelli simulates materials that carry sound only on their surface and in one direction while being immune to damage.

Active fluid

Postdoctoral researcher Anton Souslov shows a visual from his simulation (figure), depicting a structure of rings containing a so-called active fluid—a liquid consisting of self-propelled particles like bacteria or rolling colloids. The system was designed to contain twice as many rings in which the active fluid circles clockwise (red) instead of counterclockwise (blue). This endows the inside with a net clockwise motion, which turns out to have a special effect on how the material carries sound.

Unaffected sound

If you place a boom box next to one of the sides, sound won't propagate through the entire . Instead, it will move only along the edges and only in the clockwise direction. The beauty is that any damage, like the dent on the right, does not affect the sound at all. 'This concept could be useful for designing ultrasound equipment that is immune to fabrication errors,' says Souslov. 'Or devices for non-invasive surgery, where you target tumors with high-intensity ultrasound. Other applications could be soundproof walls or even optical fiber, because the principle works just as well for light waves.'

Topology

Physics enthusiasts might recognize the analogy with topological insulators, which insulate on the inside but conduct electric current on the surface. The Leiden design does the same for sound, and also finds its roots at the interface between physics and topology—a booming field that was the subject of the 2016 Physics Nobel Prize. Topological structures remain unaffected by stretching or bending. Only extreme deformations like tearing or gluing change their properties.

Explore further: Spinning electrons open the door to future hybrid electronics

More information: Anton Souslov, Benjamin C. van Zuiden, Denis Bartolo and Vincenzo Vitelli, 'Topological sound in active-liquid metamaterials', Nature Physics.

Related Stories

Metamaterial built from gears

November 22, 2016

A specifically designed collection of gears is soft on one end and rigid on the other. These robust properties hold even in the event of manufacturing imperfections. This emerging research may lead to new ways of designing ...

Soundproofing with quantum physics

July 2, 2015

Sebastian Huber and his colleagues show that the road from abstract theory to practical applications needn't always be very long. Their mechanical implementation of a quantum mechanical phenomenon could soon be used for soundproofing ...

Optical generation of ultrasound via photoacoustic effect

February 28, 2017

Limitations of the piezoelectric array technologies conventionally used for ultrasonics inspired a group of University College London researchers to explore an alternative mechanism for generating ultrasound via light, also ...

Recommended for you

Walking crystals may lead to new field of crystal robotics

February 23, 2018

Researchers have demonstrated that tiny micrometer-sized crystals—just barely visible to the human eye—can "walk" inchworm-style across the slide of a microscope. Other crystals are capable of different modes of locomotion ...

Researchers turn light upside down

February 23, 2018

Researchers from CIC nanoGUNE (San Sebastian, Spain) and collaborators have reported in Science the development of a so-called hyperbolic metasurface on which light propagates with completely reshaped wafefronts. This scientific ...

Recurrences in an isolated quantum many-body system

February 23, 2018

It is one of the most astonishing results of physics—when a complex system is left alone, it will return to its initial state with almost perfect precision. Gas particles, for example, chaotically swirling around in a container, ...

Seeing nanoscale details in mammalian cells

February 23, 2018

In 2014, W. E. Moerner, the Harry S. Mosher Professor of Chemistry at Stanford University, won the Nobel Prize in chemistry for co-developing a way of imaging shapes inside cells at very high resolution, called super-resolution ...

Hauling antiprotons around in a van

February 22, 2018

A team of researchers working on the antiProton Unstable Matter Annihilation (PUMA) project near CERN's particle laboratory, according to a report in Nature, plans to capture a billion antiprotons, put them in a shipping ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.