Scientists from the Federal Polytechnic School of Lausanne (EPFL) have created a prototype of an analog acoustic quantum computer, which they intend to develop into a full-fledged calculator based on completely different operating principles. Qubits in the proposed system will be able to literally talk to each other while in a stable acoustic superposition. In the quantum world, measurement destroys such states, but sound waves are insensitive to such influence.
Image source: EPFL
In their work, the researchers used the fact that pure sound waves, as a rule, do not exist. An acoustic signal almost always contains harmonics. This can be compared to a superposition state in the quantum world – a multitude of probabilities in one acoustic signal. This property can be used to create acoustic qubits and, accordingly, an analog acoustic quantum computer, which the scientists successfully implemented.
«“We have essentially created a quantum-mechanically inspired playground that can be tweaked to study different systems. Our metamaterial is made up of highly tunable active elements, allowing us to synthesize phenomena beyond nature,” the researchers say. “Potential applications include wave control and energy transfer for telecommunications, and one day this setup could help extract energy from waves.”
The setup proposed by the scientists consists of atomic “cubes”. Each “cube” is equipped with a speaker and a microphone. The microphones measure the strength (amplitude) of the signal and its frequency. In some ways, this is similar to the connection of atoms in a crystal lattice, where vibrations are transmitted from one atom to another.
The prototype of the acoustic quantum system is far from the real quantum level. Acoustic waves only approximately imitate quantum phenomena, but this imitation is accurate enough for experiments. In a sense, scientists have brought to life Schrödinger’s thought experiment about a living and simultaneously dead cat in a closed box. The cat also did not reflect the quantum level in any way, but it gave an idea of the absence of conventional logic in application to quantum phenomena.
In addition to the ability to reproduce a quantum system on a macro scale, the proposed setup can help solve a purely utilitarian problem. People often suffer from tinnitus, and the nature of this phenomenon often remains unknown. An acoustic quantum computer can become a simulator of such processes, which will help many patients with this disorder.