The superradiant phase transition (SPT) has been widely studied in cavity quantum
electrodynamics (CQED). However, this SPT is still subject to ongoing debates due to the no …

Quadratic light-matter interactions are nonlinear couplings such that quantum emitters
interact with photonic or phononic modes exclusively via the exchange of excitation pairs …

We employ a polaron picture to investigate the properties of the two-photon quantum Rabi
model (QRM), which describes a two-level or spin-half system coupled with a single bosonic …

A spin-boson-like model with two interacting qubits is analysed. The model turns out to be
exactly solvable since it is characterized by the exchange symmetry between the two spins …

We prove that superradiant phase transitions (SPTs) of the Dicke model and its
generalizations in the thermodynamic and classical oscillator limit are indeed of the same …

We demonstrate the emergence of selective k-photon interactions in the strong and
ultrastrong coupling regimes of the quantum Rabi model with a Stark coupling term. In …

The quantum Rabi model (QRM) is a fundamental model for light-matter interactions. A
fascinating feature of the QRM is that it manifests a quantum phase transition which is …

The light–matter interaction not only is ubiquitous in nature but also can be simulated in
various artificial systems. Besides the tunability of artificial quantum systems, the …

Quantum Rabi model (QRM) is fascinating not only because of its broad relevance but also
due to its few-body quantum phase transition. In practice, both the bias and the nonlinear …

Universality is a common quality in different physical parameters that is rooted in the deep
nature of physical systems. Scaling relation is a typical universality for critical phenomena …