Curator's Take
AI Commentary
This article demonstrates that a simple dc‑voltage‑biased SQUID can generate clean multi‑photon loss channels without the unwanted nonlinearities that plague traditional parametric pumps, opening a more hardware‑efficient path to reservoir engineering for bosonic qubits. By converting one, two or four photons from a high‑Q mode into a single photon of a lossy mode and verifying the two‑photon process with Wigner tomography, the work provides a practical toolkit for stabilizing cat‑states—an essential step toward fault‑tolerant quantum processors. The approach sidesteps pump‑induced heating and frequency crowding, but scaling to larger processor architectures will still require careful integration of bias lines and loss engineering.
— Mark Eatherly
Summary
Multi-photon dissipation -- a key resource for bosonic qubits -- is usually realized by parametrically pumping a Josephson coupler at the cost of spurious nonlinear terms. Here we instead engineer it using a dc-voltage-biased SQUID, such that these parasitic terms average out. We activate the conversion of one, two, or four photons of a high-Q mode into a single photon of a lossy mode. We characterize the two-photon dissipation by Wigner tomography, establishing dc-biased junctions as a resource for reservoir engineering and a viable route to cat-qubit stabilization.