Non-Hermitian extension of gauge theories and implications for neutrino physics

An extension of QED is considered in which the Dirac fermion has both Hermitian and anti-Hermitian mass terms, as well as both vector and axial-vector couplings to the gauge field. Gauge invariance is restored when the Hermitian and anti-Hermitian masses are of equal magnitude, and the theory reduces to that of a single massless Weyl fermion. An analogous non-Hermitian Yukawa theory is considered, and it is shown that this model can explain the smallness of the light-neutrino masses and provide an additional source of leptonic CP violation.Comment: 23 pages, 1 figure, JHEP style; corrections to match published versio

A simple explanation for 66.7% limiting values in tetrad analysis

Simple explanation for 66.7% limiting values in tetrad analysi

Research for alternative material and its effect on seed germination in seed tapes products

‘Seed tapes’ are a length of biodegradable tissue paper, acting as a carrier, containing seeds. The seed tape is unrolled into a shallow trench and covered with soil, ensuring that all seeds are planted at even intervals. Manufacturers in the seed tape industry aim to produce products with crop sizes that are as good as, or better than, loose seeds. However, little is known about the principal component that affects the crop size produced by seed tapes, the carrier material, and its influential properties.The focus of this report is to describe a multi-phased experiment, used to test the suitability of alternative seed tape materials. The experiment analysed the performance of the seed tape products on a number of matrices; germination count, germination rate, penetration count and penetration rate; all are factors that influence the growth performance of the seed tapes. The fundamental performance indicator for consumers is crop size, which is measured by the penetration of seedlings through the seed tape material

Visualising quantum effective action calculations in zero dimensions

© 2019 IOP Publishing Ltd. We present an explicit treatment of the two-particle-irreducible (2PI) effective action for a zero-dimensional quantum field theory. The advantage of this simple playground is that we are required to deal only with functions rather than functionals, making complete analytic approximations accessible and full numerical evaluation of the exact result possible. Moreover, it permits us to plot intuitive graphical representations of the behaviour of the effective action, as well as the objects out of which it is built. We illustrate the subtleties of the behaviour of the sources and their convex-conjugate variables, and their relation to the various saddle points of the path integral. With this understood, we describe the convexity of the 2PI effective action and provide a comprehensive explanation of how the Maxwell construction arises in the case of multiple, classically stable saddle points, finding results that are consistent with previous studies of the one-particle-irreducible (1PI) effective action

Boltzmann equations for preheating

We derive quantum Boltzmann equations for preheating by means of the density matrix formalism, which account for both the non-adiabatic particle production and the leading collisional processes between the produced particles. In so doing, we illustrate the pivotal role played by pair correlations in mediating the particle production. In addition, by numerically solving the relevant system of Boltzmann equations, we demonstrate that collisional processes lead to a suppression of the growth of the number density even at the very early stages of preheating

Alternative flow equation for the functional renormalization group

We derive an alternative to the Wetterich-Morris-Ellwanger equation by means of the two-particle irreducible (2PI) effective action, exploiting the method of external sources due to Garbrecht and Millington. The latter allows the two-point source of the 2PI effective action to be associated consistently with the regulator of the renormalization group flow. We show that this procedure leads to a flow equation that differs from that obtained in the standard approach based on the average one-particle irreducible effective action

A microfluidics tool for high-throughput, real-time multimodal imaging of nanoparticle-cell interactions

The increasing use of nanomaterials for biomedical applications has raised the need for efficient, robust and low-cost high-throughput assessment of nanotoxicity and cell-nanoparticle interactions. Microfluidics provides the tools for high-throughput single-cell functional monitoring, while gold nanorods have unique potential for intracellular tracking and can simultaneously be used as drug carriers. Presented here is a miniaturised platform that integrates these features with a multimodal approach to cell imaging. A microfluidic device allows for trapping of an array of singlecells, followed by the controlled delivery of nanoparticles into the cell array and subsequent real-time multimodal imaging of cellular interactions with functionalised nanoparticles. This system has been successfully used to assess cellnanoparticle interactions at the single-cell level