Dynamically modulated light-matter interactions for ancilla-tolerant bosonic control

Abstract

Strong light-matter interactions are central to state-of-the-art quantum technologies, spanning platforms as diverse as Rydberg atoms, trapped ions, and superconducting circuits. In superconducting circuits, the strong dispersive coupling between microwave photons (light) and ancillary qubits (matter) has enabled universal bosonic control and quantum error correction. However, this always-on dispersive interaction propagates errors from the ancillary qubits to the bosonic systems both while idling and when performing operations, introducing a trade-off between control strength and fidelity. We break this trade-off by introducing a parametrically activated hybridization between the bosonic modes and ancilla qubits, keeping both elements decoupled when not active. When activated, this hybridization mediates a dynamic light-matter coupling with non-trivial engineered symmetries, permitting resilience to ancilla decay and dephasing. This dynamic coupling functions as a new control primitive that offers a route to bosonic processors whose performance is set by the oscillator, rather than the ancilla.