145 research outputs found
Ultrahigh Purcell factors and Lamb shifts using slow-light metamaterial waveguides
Employing a medium-dependent quantum optics formalism and a Green function
solution of Maxwell's equations, we study the enhanced spontaneous emission
factors (Purcell factors) and Lamb shifts from a quantum dot or atom near the
surface of a %embedded in a slow-light metamaterial waveguide. Purcell factors
of approximately 250 and 100 are found at optical frequencies for polarized
and polarized dipoles respectively placed 28\thinspace nm (0.02\thinspace
) above the slab surface, including a realistic metamaterial loss
factor of . For smaller loss values, we
demonstrate that the slow-light regime of odd metamaterial waveguide
propagation modes can be observed and related to distinct resonances in the
Purcell factors. Correspondingly, we predict unusually large and rich Lamb
shifts of approximately -1 GHz to -6 GHz for a dipole moment of 50 Debye. We
also make a direct calculation of the far field emission spectrum, which
contains direct measurable access to these enhanced Purcell factors and Lamb
shifts
Lifestyle Factors in Hypertension Drug Research: Systematic Analysis of Articles in a Leading Cochrane Report
Established standards for first-line hypertension management include lifestyle modification and behavior change. The degree to which and how lifestyle modification is systematically integrated into studies of first-line drug management for hypertension is of methodological and clinical relevance. This study systematically reviewed the methodology of articles from a recent Cochrane review that had been designed to inform first-line medical treatment of hypertension and was representative of high quality established clinical trials in the field. Source articles (n=34) were systematically reviewed for lifestyle interventions including smoking cessation, diet, weight loss, physical activity and exercise, stress reduction, and moderate alcohol consumption. 54% of articles did not mention lifestyle modification; 46% contained nonspecific descriptions of interventions. We contend that hypertension management research trials (including drug studies) need to elucidate the benefits and risks of drug-lifestyle interaction, to support the priority of lifestyle modification, and that lifestyle modification, rather than drugs, is seen by patients and the public as a priority for health professionals. The inclusion of lifestyle modification strategies in research designs for hypertension drug trials could enhance current research, from trial efficacy to clinical outcome effectiveness, and align hypertension best practices of a range of health professionals with evidence-based knowledge translation
Spontaneous Emission Spectra and Quantum Light-Matter Interactions from a Strongly-Coupled Quantum Dot Metal-Nanoparticle System
We investigate the quantum optical properties of a single photon emitter
coupled to a finite-size metal nanoparticle using a photon Green function
technique that rigorously quantizes the electromagnetic fields. We first obtain
pronounced Purcell factors and photonic Lamb shifts for both a 7-nm and 20-nm
radius metal nanoparticle, without adopting a dipole approximation. We then
consider a quantum-dot photon emitter positioned sufficiently near to the metal
nanoparticle so that the strong coupling regime is possible. Accounting for
non-dipole interactions, quenching, and photon transport from the dot to the
detector, we demonstrate that the strong coupling regime should be observable
in the far-field spontaneous emission spectrum, even at room temperature. The
emission spectra show that the usual vacuum Rabi doublet becomes a rich
spectral triplet or quartet with two of the four peaks anticrossing, which
survives in spite of significant non-radiative decays. We discuss the emitted
light spectrum and the effects of quenching for two different dipole
polarizations.Comment: 5 figure
The stabilizing role of itinerant ferromagnetism in inter-granular cohesion in iron
We present a simple, general energy functional for ferromagnetic materials
based upon a local spin density extension to the Stoner theory of itinerant
ferromagnetism. The functional reproduces well available ab initio results and
experimental interfacial energies for grain boundaries in iron. The model shows
that inter-granular cohesion along symmetric tilt boundaries in iron is
dependent upon strong magnetic structure at the interface, illuminates the
mechanisms underlying this structure, and provides a simple explanation for
relaxation of the atomic structure at these boundaries.Comment: In review at Phys. Rev. Lett. Submitted 23 September 1997; revised 16
March 199
Transformation of Quartz to Tridymite in the Presence of Binary Silicate Liquids
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66429/1/j.1151-2916.1967.tb15146.x.pd
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