MB003 - Suppressing Logical Error with Multimode circuit QED

The essence of quantum error correction (QEC) is the ability to detect and correct errors without measuring the logical state itself. Traditional quantum error-correction approaches achieve this by redundantly encoding logical qubits across many two-level systems (qubits), at the expense of increased hardware and control overhead. In this project, we study multimode cQED devices for QEC. In multimode cQED, we engineer the physical cQED device to introduce additional degrees of freedom to the circuit, and consequently additional electromagnetic modes that can be exploited for hardware-efficient error-detection and error-correction techniques. Another application is engineering strong and ultrastrong coupling between the operational modes to realize ultrafast controlled gates for encoding logical qubits and exploring large quantum graph codes.