Observing quantum synchronization blockade in circuit quantum electrodynamics
Simon E. Nigg · Physical Review A · 2018
High-quality factors, strong nonlinearities, and extensive design flexibility make superconducting circuits an ideal platform to investigate synchronization phenomena deep in the quantum regime. Recently, it was predicted that energy quantization and conservation can block the synchronization of two identical, weakly coupled nonlinear self-oscillators [N. L\"orch et al., Phys. Rev. Lett. 118, 243602 (2017)]. Here, we propose a Josephson junction circuit realization of such a system along with a simple homodyne measurement scheme to observe this effect. We also show that at finite detuning, where phase synchronization takes place, the two oscillators are entangled in the steady state, as witnessed by the positivity of the logarithmic negativity.