Quantum Corrections to Q-Balls

We extend calculational techniques for static solitons to the case of field configurations with simple time dependence in order to consider quantum effects on the stability of Q-balls. These nontopological solitons exist classically for any fixed value of an unbroken global charge Q. We show that one-loop quantum effects can destabilize very small Q-balls. We show how the properties of the soliton are reflected in the associated scattering problem, and find that a good approximation to the full one-loop quantum energy of a Q-ball is given by $\omega - E_0$, where $\omega$ is the frequency of the classical soliton's time dependence, and $E_0$ is the energy of the lowest bound state in the associated scattering problem.Comment: 6 pages, 2 figures, uses RevTex4; v2: replaced figure

Heavy Fermion Stabilization of Solitons in 1+1 Dimensions

We find static solitons stabilized by quantum corrections in a (1+1)-dimensional model with a scalar field chirally coupled to fermions. This model does not support classical solitons. We compute the renormalized energy functional including one-loop quantum corrections. We carry out a variational search for a configuration that minimizes the energy functional. We find a nontrivial configuration with fermion number whose energy is lower than the same number of free fermions quantized about the translationally invariant vacuum. In order to compute the quantum corrections for a given background field we use a phase-shift parameterization of the Casimir energy. We identify orders of the Born series for the phase shift with perturbative Feynman diagrams in order to renormalize the Casimir energy using perturbatively determined counterterms. Generalizing dimensional regularization, we demonstrate that this procedure yields a finite and unambiguous energy functional.Comment: 27 papes Latex, equation labels corrected, version to be published in Nucl. Phys.

A Heavy Fermion Can Create a Soliton: A 1+1 Dimensional Example

We show that quantum effects can stabilize a soliton in a model with no soliton at the classical level. The model has a scalar field chirally coupled to a fermion in 1+1 dimensions. We use a formalism that allows us to calculate the exact one loop fermion contribution to the effective energy for a spatially varying scalar background. This energy includes the contribution from counterterms fixed in the perturbative sector of the theory. The resulting energy is therefore finite and unambiguous. A variational search then yields a fermion number one configuration whose energy is below that of a single free fermion.Comment: 10 pages, RevTeX, 2 figures composed from 4 .eps files; v2: fixed minor errors, added reference; v3: corrected reference added in v

Electron Optics

Contains research objectives and summary of research on one research project.Joint Services Electronics Program (Contract DAAB07-75-C-1346

Nonlinear Fluid Dynamics Description of non-Newtonian Fluids

Nonlinear hydrodynamic equations for visco-elastic media are discussed. We start from the recently derived fully hydrodynamic nonlinear description of permanent elasticity that utilizes the (Eulerian) strain tensor. The reversible quadratic nonlinearities in the strain tensor dynamics are of the 'lower convected' type, unambiguously. Replacing the (often neglected) strain diffusion by a relaxation of the strain as a minimal ingredient, a generalized hydrodynamic description of viscoelasticity is obtained. This can be used to get a nonlinear dynamic equation for the stress tensor (sometimes called constitutive equation) in terms of a power series in the variables. The form of this equation and in particular the form of the nonlinear convective term is not universal but depends on various material parameters. A comparison with existing phenomenological models is given. In particular we discuss how these ad-hoc models fit into the hydrodynamic description and where the various non-Newtonian contributions are coming from.Comment: Acta Rheologic

Spin wave mediated non-reciprocal effects in antiferromagnets

By using an effective field theory for the electromagnetic interaction of spin waves, we show that, in certain antiferromagnets, the latter induce non-reciprocal effects in the microwave region, which should be observable in the second harmonic generation and produce gyrotropic birefringency. We calculate the various (non-linear) susceptibilities in terms of a few parameters the order of magnitude of which is under control.Comment: Latex file, 22p . Published versio

Electron Optics

Contains reports on two research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346

Numerical Simulation of an Electroweak Oscillon

Numerical simulations of the bosonic sector of the $SU(2)\times U(1)$ electroweak Standard Model in 3+1 dimensions have demonstrated the existence of an oscillon -- an extremely long-lived, localized, oscillatory solution to the equations of motion -- when the Higgs mass is equal to twice the $W^\pm$ boson mass. It contains total energy roughly 30 TeV localized in a region of radius 0.05 fm. A detailed description of these numerical results is presented.Comment: 12 pages, 8 figures, uses RevTeX4; v2: expanded results section, fixed typo

Emergencies within hospital wards: An observational study of the non-technical skills of medical emergency teams

Background Medical emergency teams are essential in responding to acute deterioration of patients in hospitals, requiring both clinical and non-technical skills. This study aims to assess the non-technical skills of medical emergency teams during hospital ward emergencies and explore team members perceptions and experiences of the use non-technical skills during medical emergencies. Methods A multi-methods study was conducted in two phases. During phase one observation and assessment of non-technical skills used in medical emergencies using the Team Emergency Assessment Measure (TEAM™) was conducted; and in the phase two in-depth interviews were undertaken with medical emergency team members. Results Based on 20 observations, mean TEAM™ ratings for non-technical skill domains were: ‘leadership’ 5.0 out of 8 (±2.0); ‘teamwork’ 21.6 out of 28 (±3.6); and ‘task management’ 6.5 out of 8 (±1.4). The mean ‘global’ score was 7.5 out of 10 (±1.5). The qualitative findings identified three areas, ‘individual’, ‘team’ and ‘other’ contributing factors, which impacted upon the non-technical skills of medical emergency teams. Conclusion Non-technical skills of hospital medical emergency teams differ, and the impact of the skill mix on resuscitation outcomes was recognised by team members. These findings emphasize the importance non-technical skills in resuscitation training and well-developed processes for medical emergency teams