Engineering Sideband Interactions with the Very Small Logical Qubit (VSLQ) Device Part I*

Like most other architectures, superconducting quantum bits are extremely sensitive to unwanted interactions with the environment. Determining effective and hardware-efficient quantum error correction protocols is thus an urgent scientific priority. I will describe a simple circuit and protocol that autonomously implements the error correction process [1]. The circuit consists of two transmons connected to dissipative baths in the form of lossy cavities and driven by superconducting quantum interference device couplings. Autonomous error correction is achieved using resonances to coherently correct errored qubit states while leaving un-errored states unaffected. The design is highly hardware-efficient and eliminates the need for fast external measurement and feedback. Here, we discuss the theoretical model, highlighting features of experimental relevance. We present simulations results demonstrating coherence improvements of an order of magnitude against realistic noise models.

[1] E. Kapit. Phys. Rev. Lett.116, 150501 (2016)