N=1\mathcal{N}=1 Liouville SCFT in Four Dimensions

We construct a four supercharges Liouville superconformal field theory in four dimensions. The Liouville superfield is chiral and its lowest component is a log-correlated complex scalar whose real part carries a background charge. The action consists of a supersymmetric Paneitz operator, a background supersymmetric $\mathcal{Q}$-curvature charge and an exponential potential. It localizes semiclassically on solutions that describe curved superspaces with a constant complex supersymmetric $\mathcal{Q}$-curvature. The theory is non-unitary with a continuous spectrum of scaling dimensions. We study the dynamics on the supersymmetric 4-sphere, show that the classical background charge is not corrected quantum mechanically and calculate the super-Weyl anomaly. We derive an integral form for the correlation functions of vertex operators.Comment: 24 pages; revise

Liouville Conformal Field Theories in Higher Dimensions

We consider a generalization of the two-dimensional Liouville conformal field theory to any number of even dimensions. The theories consist of a log-correlated scalar field with a background $\mathcal{Q}$-curvature charge and an exponential Liouville-type potential. The theories are non-unitary and conformally invariant. They localize semiclassically on solutions that describe manifolds with a constant negative $\mathcal{Q}$-curvature. We show that $C_T$ is independent of the $\mathcal{Q}$-curvature charge and is the same as that of a higher derivative scalar theory. We calculate the A-type Euler conformal anomaly of these theories. We study the correlation functions, derive an integral expression for them and calculate the three-point functions of light primary operators. The result is a higher-dimensional generalization of the two-dimensional DOZZ formula for the three-point function of such operators.Comment: 20 pages; Text modified, references added. Published versio

ELECTRICITY DEREGULATION: WHAT'S IN STORE FOR THE ENVIRONMENT?

We test the: degree to which electricity consumers will trade off price and environmental attributes, effectiveness of environmental certification, and effectiveness of voluntary versus mandatory environmental disclosure. The type and consistency of information, the degree of difference in environmental attributes and the individual's characteristics all impact the choice of electricity product.Environmental Economics and Policy,

Second-Harmonic Generation in Silicon Nitride Ring Resonators

The emerging field of silicon photonics seeks to unify the high bandwidth of optical communications with CMOS microelectronic circuits. Many components have been demonstrated for on-chip optical communications, including those that utilize the nonlinear optical properties of silicon[1, 2], silicon dioxide[3, 4] and silicon nitride[5, 6]. Processes such as second harmonic generation, which are enabled by the second-order susceptibility, have not been developed since the bulk $\chi^{(2)}$ vanishes in these centrosymmetric CMOS materials. Generating the lowest-order nonlinearity would open the window to a new array of CMOS-compatible optical devices capable of nonlinear functionalities not achievable with the?$\chi^{(3)}$ response such as electro-optic modulation, sum frequency up-conversion, and difference frequency generation. Here we demonstrate second harmonic (SH) generation in CMOS compatible integrated silicon nitride (Si3N4) waveguides. The $\chi^{(2)}$ response is induced in the centrosymmetric material by using the nanoscale structure to break the bulk symmetry. We use a high quality factor Q ring resonator cavity to enhance the efficiency of the nonlinear optical process and detect SH output with milliwatt input powers.Comment: 4 pages, 3 figure

Working Together: Integrating Computational Modeling Approaches to Investigate Complex Phenomena

Complex systems are made up of many entities, whose interactions emerge into distinct collective patterns. Computational modeling platforms can provide a powerful means to investigate emergent phenomena in complex systems. Some research has been carried out in recent years about promoting students' modeling practices, specifically using technologically advanced tools and approaches that allow students to create, manipulate, and test computational models. However, not much research had been carried out on the integration of several modeling approaches when investigating complex phenomena. In this paper, we describe the design principles used to develop a middle school unit about ants' collective behavior that integrates three modeling approaches: conceptual drawn models, agent-based models, and system dynamics models. We provide results from an initial implementation of an 8th grade curricular unit, indicating that students engaged with several aspects of the modeling practice. Students' conceptual knowledge about ant pheromone communication increased following learning the unit. We also found gains in students' metamodeling knowledge about models as tools for investigating phenomena. We discuss the affordances and challenges of engaging students with several modeling approaches in science classroom

Summer 1977

Solar Energy: Wave of the Future? (page 3) Turfgrass Nutrition: Current Thinking and Future Challenges (7) Make Wine--Not Waste--with Whey (12) Potted Florist Crops for Everyday Use (15) UMass Turfgrass Research Fund (19