Quantum-mechanical effects at the macroscopic level were first explored in Josephson-
junction-based superconducting circuits in the 1980s. In recent decades, the emergence of …

The study of light–matter interaction has led to important advances in quantum optics and
enabled numerous technologies. Over recent decades, progress has been made in …

Creating a train of single photons and monitoring its propagation and interaction is
challenging in most physical systems, as photons generally interact very weakly with other …

Nonequilibrium phase transitions exist in damped-driven open quantum systems when the
continuous tuning of an external parameter leads to a transition between two robust steady …

Microwave photonics lends the advantages of fiber optics to electronic sensing and
communication systems. In contrast to nonlinear optics, electro-optic devices so far require …

Continuous variable entanglement between two modes of a radiation field is usually studied
at optical frequencies. Here we demonstrate experiments that show the entanglement …

Here, we report the experimental observation of a dynamical quantum phase transition in a
strongly interacting open photonic system. The system studied, comprising a Jaynes …

We show that a spontaneous release of virtual photon pairs can occur in a quantum optical
system in the ultrastrong coupling regime. In this regime, which is attracting interest both in …

We propose to use the intrinsic two-level system (TLS) defect states found naturally in
integrated optomechanical devices for exploring cavity QED-like phenomena with localized …

Recent progress in the development of superconducting circuits has enabled the realization
of interesting sources of nonclassical radiation at microwave frequencies. Here, we discuss …