Warwick scientists think sound vibrations, not electricity, could be the key to linking a million qubits together

[Badger27]

Researchers from the University of Warwick and NRC Canada have introduced Quantum Phononic Links, a new concept using sound like vibrations to carry quantum information between qubits positioned far apart on the same chip, published in the journal APL Quantum. Today's leading quantum chips typically only let neighboring qubits communicate directly with each other, a real bottleneck given that engineers expect useful quantum computers will eventually need to coordinate millions of qubits spread across an entire semiconductor chip rather than just small clusters of adjacent ones

The concept relies on a specialized material called compressively strained germanium on silicon, pioneered at Warwick using advanced epitaxial growth techniques, in which qubits are especially sensitive to tiny vibrations, known as phonons, passing through a thin germanium crystal layer. By carefully engineering and controlling those vibrations, the researchers showed that in principle quantum information could transfer between qubits whether they sit side by side or are separated across an entire semiconductor wafer up to 300mm in diameter. Dr Maksym Myronov of Warwick's physics department described phonons acting as a quantum bus, letting distant qubits exchange information while remaining fully compatible with existing semiconductor technology

This differs from other proposed long range qubit connection methods that rely on microwaves or externally generated surface acoustic waves, both of which typically require complex additional hardware attached to the chip. Quantum Phononic Links are instead built directly into the same semiconductor material that hosts the qubits themselves, using manufacturing techniques already compatible with established chip fabrication processes. That compatibility is the real appeal, since it points toward a potentially more compact, cheaper and more scalable route to future commercial quantum processors than approaches requiring specialized bolt on hardware for every long distance connection

Quantum Chip Architecture Built Vibrationsphys.org