The sound of a single atom has been recorded for the first time by researchers from the Chalmers University of Technology in Sweden.
Sound has been used for the first time to interact with an artificial atom. Researchers may be able to use sound waves to cause reactions in atoms that could, until now, only be carried out using electromagnetic radiation.
Sound waves travel much slower than light, providing the opportunity for researchers to control the quantum behavior of atoms with greater precision than ever before.
Light interacting with atoms has been studied in great detail by physicists, but sound effects have remained largely unexplored. Researchers were able to successfully couple acoustic waves to the artificial atom.
"We have opened a new door into the quantum world by talking and listening to atoms," Per Delsing, research group leader, said.
By harnessing quantum physics, the group hopes to see the emergence of technological feats, such as extremely fast computers. This is done by creating electrical circuits that obey quantum laws and can be controlled and studied.
Normal atoms can absorb energy, causing electrons to rise from one energy level to a higher one. Such a state is unstable, and the electron falls back to its lower energy level. Doing so releases energy, usually in the form of a photon of light. The artificial atom acts as a quantum electrical circuit, absorbing and emitting sound in the place of electromagnetic energy. Like electrons, the artificial atom absorbs and emits sound in discrete packets, or quanta, each representing the smallest amount of sound that can be traced.
"Due to the slow speed of sound, we will have time to control the quantum particles while they travel. This is difficult to achieve with light, which moves 100,000 times more quickly," Martin Gustafsson, first author of an article detailing research into the artificial atom, stated in a press release.
Atoms that interact with light need to be much smaller than the wavelength of energy for energy to interact with the particle of matter. The artificial atom was 0.0004 inches in diameter, and constructed from a superconducting material. Sound utilized in the study resonated at 4.8 GHz, 20 octaves above the highest note possible on a full-sized piano. Such frequencies allow the transmission of the sound over a microchip.
The experiments were carried out at temperatures near absolute zero, to minimize vibrations which could drown out acoustic signals. This study could be used in the development of quantum computers, thousands of times faster than today's best technology.
Investigation of the role sound waves can play in controlling quantum phenomena will be profiled in an upcoming issue of the journal Science.