Splitting phonons: Building a platform for linear mechanical quantum computing
Hong Qiao, Étienne Dumur, Gustav Andersson, Haoxiong Yan, Ming-Han Chou, Joel Grebel, Christopher R. Conner, Yash J. Joshi, Jacob M. Miller, Rhys G. Povey, Xuntao Wu, A. N. Cleland
Abstract
Linear optical quantum computing provides a desirable approach to quantum computing, with only a short list of required computational elements. The similarity between photons and phonons points to the interesting potential for linear mechanical quantum computing using phonons in place of photons. Although single-phonon sources and detectors have been demonstrated, a phononic beam splitter element remains an outstanding requirement. Here we demonstrate such an element, using two superconducting qubits to fully characterize a beam splitter with single phonons. We further use the beam splitter to demonstrate two-phonon interference, a requirement for two-qubit gates in linear computing. This advances a new solid-state system for implementing linear quantum computing, further providing straightforward conversion between itinerant phonons and superconducting qubits.