With an appearance similar to a tambourine or tambourine without rattles, the drum developed by researchers at the Colorado National Institute of Standards and Technology (NIST), in the United States, isa 100 nanometer thick round aluminum membranewhich actsboth as the vibrating skin of the drum and as the part of an electric condenser. The device, details of which are published in the magazineNature, holds the key to opening a new field in quantum physics.
The superconducting circuit of the drum exhibits unprecedented strong electromechanical coupling, a fundamental characteristic for observing and controlling durable quantum states in mechanical movements. This drum is light and flexible enough to vibrate freely even being larger and heavier than typical nanowires used in similar experiments.
“The drum achieves a perfect balance because, although it is kept at the microscale, it can be coupled strongly,” says John Teufel, lead author of the study. The experiments conducted by the scientists created stronginteractions between microwave light, which oscillates 7.5 billion times per second, and the “micro drum”, which vibrates at a radio frequency of 11 million times per second. Specifically, they passed the microwave energy at 56 megahertz (MHz or million cycles per second) per nanometer of the movement of the drum, 1,000 times more than what has been achieved so far. “We have increased the rate at which these two instruments communicate with each other,” explains Teufel. The drum motion will last hundreds of microseconds, according to the article, a relatively long time in the fast-paced quantum world.
When the drum vibrates, the capacitance changes and the mechanical movement modulates the properties of the electrical circuit. The same principle works on a microphone and FM radio, but here the natural movement of the drum, usually at one frequency, is transmitted to the listener in the laboratory.
The experiment is a step towards entanglement (a curious quantum state that correlates the properties of objects) between the photons of the microwaves and the motion of the drum, says Teufel, who adds that the device has the highest coupling force and the lower energy losses needed to generate entanglement. The drum is a key achievement in NIST’s efforts todevelop components for superconducting quantum computersand quantum simulations.
