Physicists demonstrate how sound can be transmitted through vacuum

https://phys.org/news/2023-08-physicists-transmitted-vacuum.html

"sound produces electricity which tunnels fully across vacuum gap between 2 piezoelectric solids... works with audio, ultrasound and hypersound frequencies, as long as gap size smaller than wavelength... In most cases the effect is small, but we also found situations where the full energy of the wave jumps across the vacuum with 100% efficiency, without any reflections. As such, the phenomenon could find applications in microelectromechanical components (MEMS, smartphone technology) and in the control of heat"