Time-modulated systems

Quantum emitter arrays, in which the emitter resonance frequencies are not fixed but are dynamically modulated, provide exciting new avenues for controlling both the direction and the quantum correlations of emitted photons.

One of our recent collaborative projects with experimentalists at the Institute of Science and Technology in Austria has demonstrated on-demand tunable directional scattering (Nat. Commun, 2023). This was achieved using two periodically modulated transmon qubits coupled to a transmission line at a fixed distance. By adjusting the relative phase between the modulation tones, we managed to accomplish unidirectional forward or backward photon scattering. This in-situ switchable mirror technology serves as a versatile tool for intra- and inter-chip microwave photonic processors. Looking ahead, we anticipate that a lattice of qubits could be utilized to create topological circuits that display strong non-reciprocity or chirality.

Additionally, we have recently developed a theoretical framework to dynamically engineer quantum correlations and entanglement in the frequency-comb emission from an array of superconducting qubits in a waveguide (Phys. Rev. Lett., 2023). When the resonance frequencies of the two qubits are periodically modulated with a π-phase shift, our theory predicts simultaneous bunching and antibunching in cross-correlations as well as Bell states of the scattered photons from different sidebands.

Selected publications


In collaboration with experimentalists