Quantized current steps due to the synchronization of microwaves with Bloch oscillations in small Josephson junctions.

Synchronization of Bloch oscillations in small Josephson junctions (JJs) under microwave radiation, which leads to current quantization, has been proposed as an effect that is dual to the appearance of Shapiro steps. This current quantization was recently demonstrated in superconducting nanowires in a compact high-impedance environment. Direct observation of current quantization in JJs would confirm the synchronization of Bloch oscillations with microwaves and help with the realisation of the metrological current standard.

Evolution of Propagating Coherent Pulses Driving a Single Superconducting Artificial Atom.

An electromagnetic wave propagating through a waveguide with a strongly coupled two-level superconducting artificial atom exhibits an evolving superposition with the atom. The Rabi oscillations in the atom result from a single excitation-relaxation, corresponding to photon absorption and stimulated emission from and to the field. In this study, we experimentally investigated the time-dependent behavior of the field transmitted through a waveguide with a strongly coupled transmon.

Quantized current steps due to the a.c. coherent quantum phase-slip effect.

The a.c. Josephson effect predicted in 1962 and observed experimentally in 1963 as quantized 'voltage steps' (the Shapiro steps) from photon-assisted tunnelling of Cooper pairs is among the most fundamental phenomena of quantum mechanics and is vital for metrological quantum voltage standards.

Photon Transport in a Bose-Hubbard Chain of Superconducting Artificial Atoms.

We demonstrate nonequilibrium steady-state photon transport through a chain of five coupled artificial atoms simulating the driven-dissipative Bose-Hubbard model. Using transmission spectroscopy, we show that the system retains many-particle coherence despite being coupled strongly to two open spaces. We find that cross-Kerr interaction between system states allows high-contrast spectroscopic visualization of the emergent energy bands.