Harvard researchers use sound waves to triple a qubit's memory time

[UltraShane86]

Researchers at Harvard's John A. Paulson School of Engineering and Applied Sciences demonstrated a way to protect fragile quantum information using mechanical vibrations, microscopic sound waves called phonons, extending a diamond-based qubit's coherence time roughly threefold. The work, published in Nature Physics, specifically targets quantum networking approaches that use phonons to carry information between qubit nodes, since phonons have much shorter wavelengths than light at the same frequency, allowing considerably smaller, more tightly packed components on a chip

The challenge is that phonon-based systems have historically struggled to combine strong interaction between phonons and qubits with the long coherence times needed for genuinely useful quantum memory, since the conventional microwave pulses normally used to protect quantum memory from environmental noise don't work well inside the phononic cavities phonon-based systems depend on. The Harvard team solved this by continuously applying a mechanical driving field to a silicon-vacancy spin in diamond, transforming it into what they call a dressed qubit that effectively wears a continuous acoustic field, making it considerably less vulnerable to low-frequency environmental noise

Because the protection method itself uses the same phonons the system depends on for interaction and networking, it's compatible with the phononic cavities these systems already require, unlike microwave-based protection. Lead author Eliza Cornell said the work demonstrates a way to extend coherence time that's compatible with the silicon-vacancy center actually sitting inside a cavity. Curious what people think this specific approach unlocks practically, does solving the coherence versus interaction tradeoff for phonon-based qubits meaningfully advance compact, chip-scale quantum networking specifically, or is this one of several competing approaches still needing much more development before any of them clearly wins out

Tiny sound waves could help solve a major quantum computing problemwww.sciencedaily.com