SciPost Physics Lecture Notes

SciPost Phys. Lect. Notes 72 (2023) · published 16 June 2023

Part of the 2019-07: Quantum Information Machines Collection in the Les Houches Summer School Lecture Notes Series.

• doi: 10.21468/SciPostPhysLectNotes.72
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Abstract

These are the lecture notes from the 2019 Les Houches Summer School on "Quantum Information Machines". After a brief introduction to quantum error correction and bosonic codes, we focus on the case of cat qubits stabilized by a nonlinear multi-photon driven dissipation process. We argue that such a system can be seen as a self-correcting qubit where bit-flip errors are robustly and exponentially suppressed. Next, we provide some experimental directions to engineer such a multi-photon driven dissipation process with superconducting circuits. Finally, we analyze various logical gates that can be implemented without re-introducing bit-flip errors. This set of bias-preserving gates pave the way towards a hardware-efficient and fault-tolerant quantum processor.

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