James McNeil

The Metal Detector and Faraday's Law

Electromagnetism has proven a notoriously difficult subject for beginning physics and engineering students. When simultaneously exercising their newly acquired calculus skills on abstract electromagnetism concepts, these students often lose the physics in the mathematical formalism. One way we have addressed this problem is by including engineering-style design and fabrication activities in the laboratory portion of the course. In addition to providing concrete examples of the electromagnetic concepts under study, the integration of mathematics and physics concepts in the design activities can significantly raise the level of student interest, increase the ownership of their learning, and ultimately improve learning and retention.

Impact performance of standard tabletop and constant equivalent fall height snow park jumps

The theory of snow park jump design that controls landing impact has been developed, but ski resorts have not exploited this advancement, in part, because of questions of practicality. In a first step to provide a proof-of-principle example, we designed and built a novel constant equivalent fall height (EFH) snow park jump at the Tognola Ski Resort in San Martino di Castrozza, Italy. The impact performance of this jump and that of an existing standard tabletop jump were measured using a jumper on a snowboard instrumented with accelerometers. Using only the accelerometer channel perpendicular to the snowboard plane, we were able to estimate the velocity changes at impact perpendicular to the landing surface, the corresponding EFH, and approximate values of the energy absorbed on impact. These were found to be in rough agreement with the theoretical expectations for EFH derived from the measured jump profiles, including trends for the tabletop jump EFH as a function of distance jumped that have been described in the literature. Language: en

Relativistic nuclear matter with self-consistent correlation energy

We study relativistic nuclear matter in the [sigma]-[omega] model including the ring-sum correlation energy. The model parameters are adjusted self-consistently to give the canonical saturation density and binding energy per nucleon with the ring energy included. Two models are considered, mean-field theory where we neglect vacuum effects, and the relativistic Hartree approximation where such effects are included but in an approximate way. In both cases we find self-consistent solutions and present equations of state. In the mean-field case the ring energy completely dominates the attractive part of the energy density and the elegant saturation mechanism of the standard approach is lost, namely, relativistic quenching of the scalar attraction. In the relativistic Hartree approach the vacuum effects are included in an approximate manner using vertex form factors with a cutoff of 1--2 GeV, the range expected from QCD. Due to the cutoff, the ring energy for this case is significantly smaller, and we obtain self-consistent solutions which preserve the basic saturation mechanism of the standard relativistic approach.

Renormalization group flow equations for the sigma model

We present a nonperturbative renormalization group solution of the Gell-Mann--Levy

Designing tomorrow’s snow park jump

\sigma

Dynamical analysis of winter terrain park jumps

-model which was originally proposed as a phenomenological description of the dynamics of nucleons and mesons. In our version of the model the fermions are interpreted as quarks which interact via the

From fundamental fields to nuclear phenomena

\sigma

A design rationale for safer terrain park jumps that limit equivalent fall height

and

Instability of infinite nuclear matter in the sigma - omega model.

\pi

The Inverting Effect of Curvature in Winter Terrain Park Jump Takeoffs

mesons. We derive and numerically solve renormalization group (RG) flow equations to leading order in a derivative expansion to study the behavior of the model as it evolves from high to low momentum scales. We develop an expansion in chiral-symmetry-breaking which enables us to track this symmetry breaking with the evolution of the scale. We use infrared observables to constrain the phenomenology allowing predictions of other quantities such as