A superlens is something that focuses audio into much smaller regions than their soundwaves normally allow. Essentially, "the cans act as resonators, directing the volume of the sound to peak in a space just a few centimetres wide, and this heightened precision could improve acoustic-actuator systems." And wouldn't you know it, but soda cans are perfect for the job.
The system works by getting 49 cans together in a seven-by-seven square, which allows the researchers to get the cans to resonate collectively. Of course, it's more complicated than just playing music near them. Instead, they played a single tone from eight different speakers arranged precisely around the cans.
What's the upshot? Well, in theory this could help them use sound waves to move physical objects. I want a sound gun that can move furniture, please. Willing to drink as many cans of beer as it takes.