In the pursuit of fault-tolerant quantum computing, the ability to store quantum information in qubits for extended durations is essential. Superconducting qubits have emerged as a leading technology due to their scalability and compatibility with existing fabrication techniques. However, improving the coherence times of these qubits remains a significant challenge, as they are typically susceptible to various sources of noise. Achieving longer coherence times is critical because it enables higher gate fidelities, which in turn reduces the hardware overhead required for fault-tolerant quantum computing.
To date, the most long-lived superconducting qubits are bosonic qubits encoded as single-photon states in three-dimensional microwave cavities. While these cavities have demonstrated impressive coherence times of up to 2 milliseconds, they face several limitations—notably, errors induced by the on-chip superconducting qubits used to control the bosonic qubit constrain their performance.
Q-CIRC aims to push the boundaries of superconducting bosonic qubit coherence by innovating across multiple fronts. First, we will design and produce advanced superconducting cavities that better protect quantum information from decoherence, leveraging novel materials, surface treatments, and configurations. Second, we will develop new methods based on active feedback control to mitigate errors in real time, enhancing the coherence of the encoded information. Third, we plan to implement quantum error detection and correction directly at the physical hardware level, thereby further reducing the impact of errors on qubit coherence.
By addressing these challenges, Q-CIRC seeks to set the stage for a new generation of high-coherence superconducting qubits with improved gate fidelities and enhanced quantum error correction performance.
