Environment-Assisted Generation of Non-Gaussian Wave-Packet Quantum States

Generating non-Gaussian states and converting them into traveling wave packets is crucial yet challenging for scalable, fault-tolerant quantum computing. We present a hardware-efficient approach that simultaneously achieves both tasks by combining an engineered nonlinear dissipation with a linear transmission loss from a superconducting circuit to a waveguide. This combination of dissipative channels leverages low-order interactions to induce a high-order nonlinearity, enabling deterministic emission of a wide range of non-Gaussian, error-correctable states, such as Schrödinger cat states, Gottesman-Kitaev-Preskill states, and pair-cat states. We identify experimental superconducting-circuit platforms and realistic parameter regimes for our proposal.