Phys.org  June 24, 2022 Researchers in the Netherlands used a cavity–waveguide architecture, where the cavity is used as a source and detector for the mechanical excitations while the waveguide has a free-standing end to reflect the phonons. This enabled them to observe multiple round trips of phonons between the source and the reflector. The long mechanical lifetime of almost 100 μs demonstrated the possibility of nearly lossless transmission of single phonons over tens of centimetres. Their experiment demonstrated full on-chip control over travelling single phonons strongly confined in the direction transverse to the propagation axis, potentially enabling a time-encoded multimode quantum […]