The scientists at the California Institute of Technology have demonstrated a new method for the quantum information storage that extends its lifetime by the factor of 30 compared to traditional superconducting systems. This achievement is considered a major step toward creation of the practical and scalable quantum computers able not only to perform fast calculations but also to reliably store the results.
Modern quantum computers are mainly built on superconducting qubits which demonstrate high speed and allow complex operations not available to classical systems. However, they have a serious limitation as they do not retain quantum states well. Information quickly “decays,” which prevents such computers from usage in practical applications. This is why researchers worldwide are looking for reliable options for “quantum memory.”
The team from the California Institute of Technology has offered an unusual solution to this problem: converting the electrical form of quantum information into an acoustic form, i.e., sound.
To implement this idea, the researchers created a miniature device – a mechanical oscillator resembling a tiny tuning fork. Its flexible plates vibrate at gigahertz frequencies and are able to receive electrical signals, converting them into acoustic phonons— sound quanta. In this form, quantum information is stored much longer. Measurements have shown that the oscillator retains the quantum state about 30 times more efficiently than the best superconducting qubits.
An advantage of this approach lies in the characteristics of the sound waves themselves. Unlike electromagnetic waves, they propagate more slowly and remain localized, which reduces energy leakage and avoids unwanted interactions with the neighboring devices. This means that an entire network of such “tuning forks” can be placed on a single crystal, creating a scalable quantum memory system.
Experiments have confirmed that acoustic oscillators are able to maintain quantum states, showing minimal interaction between the electromagnetic and the sound vibrations — a key condition for stability.
The researchers emphasize that the task is still far from complete: the efficiency of information exchange between qubits and oscillators needs improvement, and the technology needs integration into real quantum processors. Nevertheless, the very demonstration that sound is capable of holding quantum data for such a long time opens up new perspectives. In the future, such devices could form the basis for quantum computers able to not only perform calculations in superposition, but also to “remember” the results long enough to be useful.
