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In this work, the previous studies investigating the potential of integrated devices using polariton waveguides that form codirectional couplers is extended. For suitable coupler parameters, a transfer of condensates between the arms of the coupler occurs leading to the observation of previously predicted Josephson‐like oscillations. The ability to tune the periodicity of these oscillations opens the way to the design of polaritonic circuits in which the directionality of the signal towards the output terminals can be controlled, for a fixed separation between the arms, varying the coupling length. The response of the devices to linearly polarized excitation is also investigated, delving into the dynamics of linear polarization at the output terminals of long couplers, providing valuable insights into their potential applications, including polariton switches and logic gates with efficient operation. The results are supported by numerical simulations based on the generalized Gross–Pitaevskii equation describing the dynamics of coherent polaritons in spatially non‐uniform systems, reproducing the polariton distribution on the output terminals and an oscillatory dependence of the corresponding emission as a function of the polarization azimuth. How the coupling and the controllable polarization degree of freedom in polariton couplers opens avenues for innovative optical architectures and functionalities is shown here. [ABSTRACT FROM AUTHOR]

Polariton condensates' propagation is strongly dependent on the particular energy landscape the particles are moving upon, in which the geometry of the pathway laid for their movement plays a crucial role. Bends in the circuit's trajectories affect the condensates' speed and oblique geometries introduce an additional discretization of the polaritons' momenta due to the mixing of short and long axis wavevectors on the propagating eigenvalues. In this work, the nature of the propagation of condensates along the arms of a polariton coupler is studied by a combination of time‐resolved micro‐tomography measurements and a theoretical model based on a mean field approximation where condensed polaritons are described by an equation for the slow varying amplitude of the polariton field coupled to an equation for the density of incoherent excitons. [ABSTRACT FROM AUTHOR]

This editorial provides a short overview of the focus issue on Bose condensation phenomena in atomic and solid state physics sponsored by the POLATOM ESF Research Networking Programme. [ABSTRACT FROM AUTHOR]

The broadenings of the E1 and E1+Δ1 interband critical points can be understood as lifetime effects due to the ultrafast relaxation of the photoexcited hot holes. The contributions to these broadenings arising from the electrons in the conduction band are small, as intervalley scattering times are rather long. We have measured such broadenings in Si, Ge, α-tin, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, and InSb with spectroscopic ellipsometry and compare them with calculations based on the deformation potential-type electron-phonon interaction in the rigid pseudo-ion approximation. [ABSTRACT FROM AUTHOR]

The thermal robustness of traveling polariton condensates is investigated. We create remote condensates that have never been in contact, and study their interference in momentum space, when they travel with the same velocity, by means of time‐resolved photoluminescence. We determine the condensed to thermal, uncondensed polariton fraction, which shows a gradual decay with increasing temperature, and obtain the critical temperature for the Bose‐Einstein‐like condensate (BEC) phase transition. We tentatively compare our experimental findings with theoretical models, developed for atomic condensates, to describe the condensates' coherence fading with temperature. [ABSTRACT FROM AUTHOR]

We report on the influence of disorder on an exciton-polariton condensate in a ZnO-based bulk planar microcavity and compare experimental results with a theoretical model for a nonequilibrium condensate. Experimentally, we detect intensity fluctuations within the far-field emission pattern even at high condensate densities, which indicates a significant impact of disorder. We show that these effects rely on the driven dissipative nature of the condensate and argue that they can be accounted for by spatial phase inhomogeneities induced by disorder, which occur even for increasing condensate densities realized in the regime of high excitation power. Thus, nonequilibrium effects strongly suppress the stabilization of the condensate against disorder, contrary to what is expected for equilibrium condensates in the high-density limit. Numerical simulations based on our theoretical model reproduce the experimental data. [ABSTRACT FROM AUTHOR]

In popular culture, positive emotions are often portrayed as performance enhancing (e.g., "happy students learn better"). However, the relationship between emotions and performance is not always straightforward. For instance, when positive emotions become too intense, they can harm cognitive performance. Do people's lay theories of emotions capture this complex relationship between emotions and performance? If so, how early in development do children grasp this nuanced relationship? In three preregistered experiments, we explored children's and adults' beliefs about the impact of different emotional states on attention in school. In Study 1a, we found that 5- to 7-year-old Canadian children ( N = 90) and North American adults ( N = 55) strongly predicted that happy characters would be better at paying attention in school compared to sad characters, but only adults predicted better attention for a mildly happy character compared to a very happy one. Study 1b ( N = 60) shows that adults' intuitions about intense positive emotions as suboptimal for attentional tasks apply equally to child and adult characters. In Study 2, we found that children ( N = 80) perceive that the effect of intensity depends on the emotion's valence-it compounds the adverse effects of sadness and amplifies the benefits of happiness. Conversely, adults ( N = 80) believe strong emotions, regardless of their valence, are not ideal for paying attention in school. Together, our findings show a developing appreciation of the impact of emotional intensity on cognitive performance-an important aspect of children's emotion understanding with likely implications for self-regulated learning. (PsycInfo Database Record (c) 2024 APA, all rights reserved).