Exciting polaritons with quantum light

We discuss the excitation of polaritons---strongly-coupled states of light and matter---by quantum light, instead of the usual laser or thermal excitation. As one illustration of the new horizons thus opened, we introduce Mollow spectroscopy, a theoretical concept for a spectroscopic technique that consists in scanning the output of resonance fluorescence onto an optical target, from which weak nonlinearities can be read with high precision even in strongly dissipative environments.Comment: 5 pages, 3 figure

Local null controllability of the N-dimensional Navier-Stokes system with N-1 scalar controls in an arbitrary control domain

In this paper we deal with the local null controllability of the N-dimensional Navier-Stokes system with internal controls having one vanishing component. The novelty of this work is that no condition is imposed on the control domain

Adiabatically preparing quantum dot spin states in the Voigt geometry

We use mutually delayed and partially overlapping optical pulses, similar to those used in stimulated Raman adiabatic passage and its variations, for the coherent control of quantum dot spin states in the Voigt geometry. We consider the quantum dot system initially in an incoherent mixture of the two electron-spin states. We show that the application of regular delayed and partially overlapping pulses can lead to initialization. In addition, if initially delayed, partially overlapping, and simultaneously switched off pulses are applied, the initially incoherent mixture can be changed to a specifically designed coherent superposition state. We also find that due to the initial conditions of the studied quantum system, the proposed methods work for different pulse orderings

Structure of the harmonic oscillator in the space of n-particle Glauber correlators

We map the Hilbert space of the quantum harmonic oscillator to the space of Glauber’s nth-order intensity correlators, in effect showing “the correlations between the correlators” for a random sampling of the quantum states. In particular, we show how the popular g(2) function is correlated to the mean population and how a recurrent criterion to identify single-particle states or emitters, namely, g(2)<1/2g(2)<1/2, actually identifies states with at most two particles on average. Our charting of the Hilbert space allows us to capture its structure in a simpler and physically more intuitive way that can be used to classify quantum sources by surveying which territory they can access

Asymmetric coupling between two quantum emitters

We study a prototypical model of two coupled two-level systems, where the competition between coherent and dissipative coupling gives rise to a rich phenomenology. In particular, we analyze the case of asymmetric coupling, as well as the limiting case of chiral (or one-way) coupling. We investigate various quantum optical properties of the system, including its steady-state populations, power spectrum, and second-order correlation functions, and outline the characteristic features which emerge in each quantity as one sweeps through the nontrivial landscape of effective complex couplings. Most importantly, we reveal instances of population trapping, unexpected spectral features, and strong emission correlations

Resonance fluorescence spectrum of a \Lambda-type quantum emitter close to a metallic nanoparticle

We theoretically study the resonance fluorescence spectrum of a three-level quantum emitter coupled to a spherical metallic nanoparticle. We consider the case that the quantum emitter is driven by a single laser field along one of the optical transitions. We show that the development of the spectrum depends on the relative orientation of the dipole moments of the optical transitions in relation to the metal nanoparticle. In addition, we demonstrate that the location and width of the peaks in the spectrum are strongly modified by the exciton-plasmon coupling and the laser detuning, allowing to achieve controlled strongly subnatural spectral line. A strong antibunching of the fluorescent photons along the undriven transition is also obtained. Our results may be used for creating a tunable source of photons which could be used for a probabilistic entanglement scheme in the field of quantum information processing

Multivariate analysis of Vitis subgenus Vitis seed morphology

We studied 142 grapevine seed samples belonging to 5 Vitis species, 92 cultivars of Vitis vinifera, 12 feral/wild populations and 4 hybrid rootstock cultivars. Eleven different characters from the seed and one allometric index have been used. Seeds show a wide range of variation in body dimensions, and in other parameters. Two largely differentiated clusters were obtained. Coincidences with previous seed classifications are discussed. Wild extra-European species have smaller seeds. The index breadth/length (STUMMER’s index) doesn’t allow to separate wild grapevines and cultivars. It defines, however, the “wild syndrome” values above 0.8 corresponding to wild extra-European Vitis species, occasionally used as rootstocks. Ferals/wild individuals tend to display smaller berries and plumper pips than their cultivated relatives therefore “looking wild”. The multivariate analysis place together ferals/wild and related cultivars in their respective clusters and does not discriminate a cluster of wild European grapevine.