We investigate the spontaneous emission (SE) spectrum of a qubit in a lossy resonant cavity. We use neither the rotating-wave approximation nor the Markov approximation. For the weak-coupling case, the SE spectrum of the qubit is a single peak, with its location depending on the spectral density of the qubit environment. Then, the asymmetry (of the location and heights of the two peaks) of the ...

Ultrastrong coupling (USC) between phonons and vacuum photons can result in fascinating quantum phenomena, though it is difficult to achieve due the small dipole moments of solids. Here, we investigate Rabi splitting by perovskite CH3NH3PbI3 films with split ring resonators. As gap size resonator decreases, strength η increases enhanced field gap, reaching USC regime (η∼0.24) at a 100 nm. Our r...

The interaction of a J-aggregate and surface plasmon polariton modes of a subwavelength hole array have been studied in detail. By measuring the effects of hole array period, angular dispersion and concentration of the J-aggregate on the transmission of the array, the existence of a strong coupling regime is demonstrated with a Rabi splitting of 250 meV. This large splitting is explained not on...

Recent experimental advances in Positronium (Ps) physics have made it possible to produce dense Ps ensembles which Ps-Ps interactions may occur, leading the production of Ps$_2$ molecules and paving way realization a Bose-Einstein Condensate (BEC). In order achieve this latter goal would be advantageous develop new methods measure densities real-time. Here we describe approach do using polarito...