Speaker: Frederik Nathan, Niels Bohr Institute, University of Copenhagen 
Title: Self-correcting qubits: harnessing dissipation for quantum error correction in driven-dissipative circuits

Abstract:
We propose a protocol for creating and dissipatively error-correcting a qubit encoded in the Fock space of a superconducting resonator mode. The device consists of a high-impedance LC resonator coupled to a Josephson junction and a resistor through a time-dependent switch. Controlling the switch via a particular family of stepwise protocols drives the system into a regime of complete dissipative error correction, where the resistor acts as a sink for noise-induced entropy, leading it to correct both dephasing and bit-flip errors. We confirm the emergence of dissipative error correction in simulations, and show that it leads to exponential enhancement of coherence time, reaching macroscopic (+10 ms) scales for near-feasible parameters, even in the presence of extrinsic noise. The qubit supports self-correcting Clifford gates, where control noise is dissipatively corrected, leading to exponentially-scaling gate fidelity. A self-correcting non-Clifford gate can be implemented by augmenting the circuit with ancilla Josephson junctions.