Decoherence-protected qubits

Superconducting qubits are microwave circuits in which the cooper-pair condensate effectively behaves as a one-dimensional quantized particle. By inserting Josephson junctions, the circuit can be made nonlinear, allowing us to isolate the qubit from higher-energy levels. Different circuit topologies with varying parameter regimes have created a zoo of different qubits, all of which suffer from different kinds of decoherence processes. We aim to construct circuits that have built-in protection against noise from the environment. 

A particularly promising approach is autonomous quantum error correction, in which we engineer the environment so that the qubit is continuously stabilized in the correct subspace, without learning anything about the qubit superposition state. 

Relevant literature:

Kapit et al., Hardware-Efficient and Fully Autonomous Quantum Error Correction in Superconducting Circuits. Phys. Rev. Lett. 116, 150501 (2016).