Solitonic dispersive hydrodynamics: theory and observation

Ubiquitous nonlinear waves in dispersive media include localized solitons and extended hydrodynamic states such as dispersive shock waves. Despite their physical prominence and the development of thorough theoretical and experimental investigations of each separately, experiments and a unified theory of solitons and dispersive hydrodynamics are lacking. Here, a general soliton-mean field theory is introduced and used to describe the propagation of solitons in macroscopic hydrodynamic flows. Two universal adiabatic invariants of motion are identified that predict trapping or transmission of solitons by hydrodynamic states. The result of solitons incident upon smooth expansion waves or compressive, rapidly oscillating dispersive shock waves is the same, an effect termed hydrodynamic reciprocity. Experiments on viscous fluid conduits quantitatively confirm the soliton-mean field theory with broader implications for nonlinear optics, superfluids, geophysical fluids, and other dispersive hydrodynamic media.Comment: 8 pages, 5 figure

Coherent population trapping in quantized light field

A full quantum treatment of coherent population trapping (CPT) is given for a system of resonantly coupled atoms and electromagnetic field. We develop a regular analytical method of the construction of generalized dark states (GDS). It turns out that GDS do exist for all optical transitions $F_g\to F_e$, including bright transitions $F\to F+1$ and $F''\to F''$ with $F''$ a half-integer, for which the CPT effect is absent in a classical field. We propose an idea to use an optically thick medium with a transition $F''\to F''$ with $F'' \ge 3/2$ a half-integer as a ''quantum filter'', which transmits only a quantum light.Comment: revtex4, twocolumn, 6 pages, including 1 figur

The relationship between dietary intake and the six dimensions of wellness in older adults

The purpose of this review was to provide older adults with a clear idea of how dietary patterns can improve wellness, and how wellness can improve dietary patterns. A large portion of the US population is advancing in age and there is potential for an associated plateau or decline in wellness with age. Therefore, strategies to improve personal wellness and dietary patterns should be considered. This review examined the associations between dietary intake and each of the six dimensions of wellness, as defined by the National Wellness Institute, in adults 50 years old or older. A cause-and-effect relationship of specific dietary patterns on intellectual, occupational, emotional, and physical wellness was explored. In addition, studies regarding the cause-and-effect relationship of spiritual and social wellness on dietary choice were evaluated. Essentially, dietary intake and wellness were closely related. The research suggests that intellectual, occupational, emotional, and physical wellness may improve with dietary changes. Nutrition status may improve with enrichment in social and spiritual wellness. Overall, older adults can enhance wellness by following a few simple guidelines: increase the intake of plant-based foods, avoid processed foods, engage in a spiritual community that encourages healthy lifestyles, and seek dining companions in order to increase caloric intake.

Single-shot optical conductivity measurement of dense aluminum plasmas

The optical conductivity of a dense femtosecond laser-heated aluminum plasma heated to 0.1-1.5 eV was measured using frequency-domain interferometry with chirped pulses, permitting simultaneous observation of optical probe reflectivity and probe pulse phase shift. Coupled with published models of bound-electron contributions to the conductivity, these two independent experimental data yielded a direct measurement of both real and imaginary components of the plasma conductivity.DOE National Nuclear Security Administration DE-FC52-03NA00156Physic

Atomic Squeezing under Collective Emission

Atomic squeezing is studied for the case of large systems of radiating atoms, when collective effects are well developed. All temporal stages are analyzed, starting with the quantum stage of spontaneous emission, passing through the coherent stage of superradiant emission, and going to the relaxation stage ending with stationary solutions. A method of governing the temporal behaviour of the squeezing factor is suggested. The influence of a squeezed effective vacuum on the characteristics of collective emission is also investigated.Comment: Latex file, 21 page, 9 figure

Developing the virtuous self in an online MBA: Reflections on instruments and processes

The relationship between virtue ethics and leadership is profound and has been the subject of sustained examination (see, for example, Fontrodona, et al. 2012). The core of these debates has centred on the way in which a life of the good, conceived as a process of self- awareness built through experience and reflection, has the capacity to comprise the people who inhabit, lead, and constitute organizations. Prima facie management education ought to entail the explicit development of the virtuous self, rather than this education being of a residual type. This requires a more reflective approach to management practice. We are challenged in this endeavour by our status as providers of online education. Our central concern in this paper is to provide an account of a Leadership Development ePortfolio, particularly its development to a program of online leadership skill development. This includes, among other skills, the development of reflective practice skills, development of self-awareness, self-mastery (Senge, 1990), and a consideration of how to apply those skills to others (e.g.: mentoring) and with others (e.g.: team learning, service learning). We argue that introducing these elements to a program fosters the development of ethically virtuous management graduates

Two-component model of the interaction of an interstellar cloud with surrounding hot plasma

We present a two-component gasdynamic model of an interstellar cloud embedded in a hot plasma. It is assumed that the cloud consists of atomic hydrogen gas, interstellar plasma is quasineutral. Hydrogen atoms and plasma protons interact through a charge exchange process. Magnetic felds and radiative processes are ignored in the model. The influence of heat conduction within plasma on the interaction between a cloud and plasma is studied. We consider the extreme case and assume that hot plasma electrons instantly heat the plasma in the interaction region and that plasma flow can be described as isothermal. Using the two-component model of the interaction of cold neutral cloud and hot plasma, we estimate the lifetime of interstellar clouds. We focus on the clouds typical for the cluster of local interstellar clouds embedded in the hot Local Bubble and give an estimate of the lifetime of the Local interstellar cloud where the Sun currently travels. The charge transfer between highly charged plasma ions and neutral atoms generates X-ray emission. We assume typical abundance of heavy ions for the Local Bubble plasma and estimate the X-ray emissivity due to charge exchange from the interface between cold neutral cloud and hot plasma. Our results show that charge exchange X-ray emission from the neutral-plasma interfaces can be a non-negligible fraction of the observed X-ray emission.Comment: 9 pages, 7 figure

Superlattice Magnetophonon Resonances in Strongly Coupled InAs/GaSb Superlattices

We report an experimental study of miniband magnetoconduction in semiconducting InAs/GaSb superlattices. For samples with miniband widths below the longitudinal optical phonon energy we identify a new superlattice magnetophonon resonance (SLMPR) caused by resonant scattering of electrons across the mini-Brillouin zone. This new resonant feature arises directly from the drift velocity characteristics of the superlattice dispersion and total magnetic quantisation of the superlattice Landau level minibands.Comment: 9 pages, 8 figures, submitted to Phys. Rev.