Rasmus Wallentin recently presented his master’s thesis at 202Q-lab in the Department of Microtechnology and Nanoscience at Chalmers University of Technology. Consequently he successfully defended his master thesis at Uppsala University from the research he had conducted in 202Q-lab.
The research explores superconducting bosonic processors and the stabilization of cat states, which, when combined with 1-D error-correction codes, offer a hardware-efficient alternative to surface codes with transmon qubits.
Kerr cat qubits are commonly controlled via three-wave mixing in flux-tunable devices (SNAILs). Building on Pietro’s demonstrations of four-wave-mixing control in SNAIL devices, Rasmus’s project proposes a circuit architecture tailored specifically for four-wave mixing.
Key technical specifications of the proposal:
- Architecture: A capacitively shunted Josephson junction array, designated as the Kerr Josephson junction array oscillator (KJJA-oscillator).
- Design characteristics: The device operates at a fixed frequency and is not flux-tunable, improving resilience to flux noise.
- Error mitigation: The architecture strongly suppresses higher-order nonlinearities, aiming to reduce error sources that impact coherence times.
The chip has been characterized, and the parity-measurement readout mechanism has been demonstrated in the lab. The physical stabilization of cat states is the next operational phase for this architecture.
You can read Rasmus’s masters thesis via the link in the first comment below.
On behalf of everyone at 202Q-lab, congratulations, Rasmus. Wishing you the very best in the chapters ahead!