Development and Evaluation of Bluetooth Low-Energy Device for Electronic Encounter Metrics.

The coronavirus disease 2019 (COVID-19) pandemic led to the need for tracking of physical contacts and potential exposure to disease. Traditional contact tracing can be augmented by electronic tools called "electronic contact tracing" or "exposure notification.".

Many-Body Physics in Small Systems: Observing the Onset and Saturation of Correlation in Linear Atomic Chains.

The exact study of small systems can guide us toward relevant measures for extracting information about many-body physics as we move to larger and more complex systems capable of quantum information processing or quantum analog simulation. We use exact diagonalization to study many electrons in short 1-D atom chains represented by long-range extended Hubbard-like models. We introduce a novel measure, the Single-Particle Excitation Content (SPEC) of an eigenstate and show that the dependence of SPEC on eigenstate number reveals the nature of the ground state (ordered phases), and the onset and saturation of correlation between the electrons as Coulomb interaction strength increases.

Plasmonic properties of metallic nanoparticles: the effects of size quantization.

We examine the size quantization of plasmons in metallic nanoparticles using time-dependent density functional theory. For small particles in the quantum limit, we identify "quantum core plasmons" and "classical surface plasmons", both of which are collective oscillations comprised of multiple single-particle transitions. As particle size increases, the response of the classical surface plasmons becomes much larger than that of the quantum core plasmons.

Body weight/height relationship: Exponential solution.

Regression of weight (W) on height (H) in all higher primates is of exponential form W = a · exp(H · b) and is uniform for both nongrowing adults and growing children. Parameter a values are always close to 2.0 and b to 0.