Parametric Luminescence of Microcavity Polaritons

The spectral and dispersive emission properties are analytically determined for the two-dimensional system of exciton-polaritons in microcavities excited by a resonant and coherent optical pump. New collective excitations result from the anomalous coupling between one generic polariton state and its idler, created by the scattering of two pumped polaritons. The corresponding parametric correlation is stimulated by the emitter and idler populations and drives very efficiently the luminescence. The intrinsic properties of the collective excitations determine a peculiar emission pattern.Comment: 5 pages, 4 figures eps. Revised version following the Referee remarks. Submitted to PRB, Rapid Com

Statistics of the polariton condensate

The influence of polariton-polariton scattering on the statistics of the polariton condensate in a non-resonantly excited semiconductor quantum well embedded in a CdTe semiconductor microcavity is discussed. Taking advantage of the existence of a bottleneck in the polariton dispersion curve, the polariton states are separated into two domains: reservoir polaritons inside the bottleneck and active polaritons with wave vector q whose energy lies below the bottleneck. In the framework of the master equation formalism, the non-equilibrium stationary reduced density matrix is calculated and the statistics of polaritons in the condensate at q=0 is determined. The anomalous correlations between the polaritons in the condensate and those with wave vectors q, -q leads to an enhancement of the noise in the condensate. As a consequence, the second order correlation function of the condensate does not show the full coherence that is characteristic of laser emission.Comment: 35 pages, 5 figure

Higher order coherence of exciton-polariton condensates

The second and third order coherence functions $g^{(n)}(0) (n=2 {\rm and} 3)$ of an exciton-polariton condensate is measured and compared to the theory. Contrary to an ideal photon laser, deviation from unity in the second and third order coherence functions is observed, thus showing a bunching effect, but not the characteristics of a standard thermal state with $g^{(n)}(0)=n!$. The increase of bunching with the order of the coherence function, $g^{(3)}(0) > g^{(2)}(0)>1$, indicates that the polariton condensate is different from coherent state, number state and thermal state. The experimental results are in agreement with the theoretical model where polariton-polariton and polariton-phonon interactions are responsible for the loss of temporal coherence.Comment: 4 pages, 4 figure

Generation of Entangled N-Photon States in a Two-Mode Jaynes-Cummings Model

We describe a mathematical solution for the generation of entangled N-photon states in two field modes. A simple and compact solution is presented for a two-mode Jaynes-Cummings model by combining the two field modes in a way that only one of the two resulting quasi-modes enters in the interaction term. The formalism developed is then applied to calculate various generation probabilities analytically. We show that entanglement, starting from an initial field and an atom in one defined state may be obtained in a single step. We also show that entanglement may be built up in the case of an empty cavity and excited atoms whose final states are detected, as well as in the case when the final states of the initially excited atoms are not detected.Comment: v2: 5 pages, RevTeX4, minor text changes + 1 figure added, revised version to be published in PRA, May 200

THz intervalence band antipolaritons

THz polaritons and antipolaritons have strong potential for device applications and are a challenging field of fundamental studies. In this paper, we start from a numerically exact nonequilibrium many body solutions and adjust it to a simplified nonlinear dielectric constant approach to the optical susceptibility. The resulting expression is inserted in the wave equation to describe the coupling of TE-polarized THz radiation with an intervalence band transition in GaAs/Al0.3Ga0.7As multiple quantum wells embedded in microcavities. The energy dispersions relations leading to THz polaritons are investigated. Here we focus on the impact of dephasing and scattering processes for different structures and excitation conditions in an inverted medium leading to antipolaritons

“Trait EI in the relationship between needs fulfilment and symptoms and attitudes associated with EDs”

Eating disorders (EDs) are a set of pathologies, which have been increasing in prevalence in the recent years, suggesting the importance of studying symptoms and attitudes associated with EDs in depth. Several studies have showed that both psychological basic needs and trait emotion intelligence (trait EI) are relevant aspects of EDs, however these two aspects were never tested concurrently. Previous studies have shown that self-determined motivation could be a plausible antecedent that may account for individual variation in trait EI, and for this reason, it seems to be extremely relevant to integrate trait EI in a Self-Determination Theory (SDT) framework. The aim of this study is to test a mediation model of trait EI in the relationship between need fulfilment and eating disorders. In a sample of 159 females aged between 16 and 22 years old (M = 18.71; SD = 1.98) instruments were administered to measure the basic psychological needs, trait EI, and eating disorders. Results of this study showed that need fulfilment was negatively related to eating disorders and positively related to trait EI, whereas trait EI was negatively related to eating disorders. Furthermore, trait EI has shown a mediation role in the relation between basic psychological needs and eating disorders

“Trait EI in the relationship between needs fulfilment and symptoms and attitudes associated with EDs”

Eating disorders (EDs) are a set of pathologies, which have been increasing in prevalence in the recent years, suggesting the importance of studying symptoms and attitudes associated with EDs in depth. Several studies have showed that both psychological basic needs and trait emotion intelligence (trait EI) are relevant aspects of EDs, however these two aspects were never tested concurrently. Previous studies have shown that self-determined motivation could be a plausible antecedent that may account for individual variation in trait EI, and for this reason, it seems to be extremely relevant to integrate trait EI in a Self-Determination Theory (SDT) framework. The aim of this study is to test a mediation model of trait EI in the relationship between need fulfilment and eating disorders. In a sample of 159 females aged between 16 and 22 years old (M = 18.71; SD = 1.98) instruments were administered to measure the basic psychological needs, trait EI, and eating disorders. Results of this study showed that need fulfilment was negatively related to eating disorders and positively related to trait EI, whereas trait EI was negatively related to eating disorders. Furthermore, trait EI has shown a mediation role in the relation between basic psychological needs and eating disorders