Space and Physics
Modeling the quantum world is far from easy. The physical peculiarities of quantum mechanics are far removed from the world we inhabit, and there are systems whose complexity is even beyond mathematical descriptions. The quantum properties of solid states are a notoriously thorny problem. Now, researchers have found a way to simulate them using sound waves and a metamaterial.
Metamaterials are materials that possess exotic properties, and the metamaterial assembled at the École Polytechnique Fédérale de Lausanne (EPFL) has intriguing acoustic capabilities. The team constructed this first test of the metamaterial – consisting of 16 small cubes, or "acoustic atoms" – with openings to place speakers or microphones.
A specific outcome in a quantum system is given by its quantum probability wave. These can be in superposition, a phenomenon made famous by the quantum cat experiment, where a cat in a box with a quantum-activated poison is both dead and alive according to quantum mechanics. It’s the measurement that makes the system collapse in a specific state, so studying the system as it is – well, it’s often impossible.
The quantum acoustic atom system that has been devised by these researchers wants to probe these probability waves without disrupting them. They do that using sound waves instead, thanks to the metamaterial, which has the right properties to mimic the quantum world. The work is fascinating, but we were curious if we could actually hear the differences ourselves, so we asked the researchers for a recording of the experiment.
"We basically sent sharp 'blips', single frequencies or white noise through the active metamaterial – I’ve actually never tried to 'hear' the results until you asked," lead author Mathieu Padlewski, a graduate researcher at EPFL, told IFLScience.
"The experimental setup is composed of 16 acoustic resonators with microphones placed in front of each one of them – I’ve arbitrarily set the left audio channel on 'atom' 4 and the right channel on atom 5 so you can hear what happens between two neighboring 'atoms' when excited with one of the three sources."
The system itself can be expanded beyond the current linear setup to understand solid materials and how their macroscopic properties emerge from the quantum world. They don’t have to deal with the limitations of quantum mechanics either; the team believes that the acoustic system might have applications well beyond solid-state physics.
“We’ve essentially built a playground inspired by quantum mechanics that can be adjusted to study various systems. Our metamaterial consists of highly tunable active elements, allowing us to synthesize phenomena that extend beyond the realm of nature,” Padlewski said in a statement. “Potential applications include manipulating waves and guiding energy for telecommunications, and the setup may one day provide clues for harvesting energy from waves for instance.”
The study is published in Physical Review B.
