Researchers Demonstrate Acoustic Purcell Effect with Diamond Colour-Centre Spin Qubit

Scientists have constructed a microwave-frequency nanomechanical resonator around a colour-centre spin qubit in diamond and observed the acoustic Purcell effect, @Nature reported. A co-localized optical mode strongly couples to the excited state of the colour centre. Using that mode, the team performed single-photon-level laser spectroscopy at millikelvin temperatures.

They recorded a 10-fold faster spin relaxation when the spin qubit was tuned into resonance with a 12 GHz acoustic mode. The colour centre served as an atomic-scale probe to measure the broadband phonon spectrum of the nanostructure up to 28 GHz. The coupled system is a SiV-OMC system.

The research paper is titled 'Purcell-enhanced spin–phonon coupling with a single colour centre'. The radiative properties of emitters are inherently linked to their surrounding environment. Placing an electromagnetic resonator around emitters can enhance spontaneous emission, as shown by Purcell in the 1940s.

This approach is now routinely used in quantum computing and communication to channel photons emitted by atoms into well-defined modes and control atom–photon interactions. For solid-state emitters such as colour centres, the host lattice introduces an acoustic environment allowing excited atoms to relax by emitting phonons.

Here the specially engineered nanomechanical resonator produced the acoustic analogue of the classic Purcell enhancement.

The work establishes a new regime of control for quantum defects in solids. It paves the way for interconnects between atomic-scale quantum memories and qubits encoded in acoustic and superconducting devices.