Q47: Superconducting Kerr Cats

Wed. March 6, 3:36 p.m. – 3:48 p.m. CST

200CD

Quantum bits (qubits) that are inherently protected against certain types of errors are promising candidates for scalable quantum computing. An outstanding challenge is to control such a qubit without breaking its protection. A recent qubit - the cat-qubit - is encoded in the manifold of metastable states of a quantum dynamical system, thereby acquiring continuous and autonomous protection against bit-flips. In this superconducting circuit experiment, we implement a cat-qubit with bit-flip times exceeding ten seconds. This is a four order of magnitude improvement over previous cat-qubit implementations. We prepare and image quantum superposition states, and measure phase-flip times above 490 nanoseconds. Most importantly, we control the phase of these quantum superpositions without breaking bit-flip protection. This work demonstrates quantum operations that preserve bit-flip times above ten seconds, a necessary step to scale these dynamical qubits into fully protected hardware-efficient architectures.

Preprint : arxiv:2307.06617