7,202 research outputs found
Self-Interacting Electromagnetic Fields and a Classical Discussion on the Stability of the Electric Charge
The present work proposes a discussion on the self-energy of charged
particles in the framework of nonlinear electrodynamics. We seek magnet- ically
stable solutions generated by purely electric charges whose electric and
magnetic fields are computed as solutions to the Born-Infeld equa- tions. The
approach yields rich internal structures that can be described in terms of the
physical fields with explicit analytic solutions. This suggests that the
anomalous field probably originates from a magnetic excitation in the vacuum
due to the presence of the very intense electric field. In addition, the
magnetic contribution has been found to exert a negative pressure on the
charge. This, in turn, balances the electric repulsion, in such a way that the
self-interaction of the field appears as a simple and natural classical
mechanism that is able to account for the stability of the electron charge.Comment: 8 pages, 1 figur
Vacuum field correlations and three-body Casimir-Polder potential with one excited atom
The three-body Casimir-Polder potential between one excited and two
ground-state atoms is evaluated. A physical model based on the dressed field
correlations of vacuum fluctuations is used, generalizing a model previously
introduced for three ground-state atoms. Although the three-body potential with
one excited atom is already known in the literature, our model gives new
insights on the nature of non-additive Casimir-Polder forces with one or more
excited atoms.Comment: 9 page
Male Sexual Orientation Among Religious Men: A Discriminant Function Analysis
The ecological changes of human society especially in Western civilization via scientific, industrial, and technological revolutions have altered the foundations of what masculinity means in the l.990\u27s. This study was designed to discriminate and predict three masculine sexual orientation groups based upon father-son relations, gender, religious spirituality, psychological maltreatment/abuse, and shame. Data were obtained from 92 male volunteer participants (gay=32, heterosexual=32, x-gay=28) who identify as Christians or who affiliate with a Christian organization. Instruments used were the Boyhood Gender conformity Scale (BGCS), the Father Forgiveness Perception Scale (FFPS), the Home Environment Questionnaire (HEQ) (i.e., Child Abuse Trauma Scale), Internalized Shame Scale (ISS), the Klein Sexual Orientation Grid (KSOG), the Parental Acceptance-Rejection Questionnaire (PARQ), the Personal Information Questionnaire (PIQ), the Religious Identification and Commitment Scale (RICS), and the Sexual Trauma Scale (STS). The KSOG, PIQ, and group affiliation provided three criterion variables. Total scores on the BGCS, HEQ, ISS, PARQ, and RICS provided five predictor variables. The PIQ provided demographic information for descriptive analysis, group profiles, and group homogeneity. The PIQ and two experimental scales (FFPS & STS) added alternative predictors. Two discriminant functions were generated. The first function, Wilks\u27 Lambda = .39, Chi Square (10) 67.43, R \u3c .001, accounted for 61% of the variance of group membership. The second function, Wilks\u27 Lambda .68, Chi Square (4) = 28.01, R \u3c .001 accounted for 39% of the variance of group membership. The BGCS, ISS, and HEQ were related to the first function. The RICS and PARQ were related to the second function. The BGCS exerted the strongest influence of the first discriminant function, ;n:=.87. The RICS exerted the strongest influence on the second discriminant function, n=.so. The first function discriminated between heterosexual subjects and the other two groups. The second function discriminated between the gay and x-gay subjects. Overall the two discriminant functions correctly classified the participants 77% of the time versus about 35% chance classification. Sixty-nine percent (n=22) of the gay participants, 84% (n=27) of the heterosexual participants, and 79% (n=22) of the gay participants were correctly classified. The findings indicate that boyhood masculine gender nonconformity is a strong indicator of adult homosexuality (gay & x-gay) and that high Christian religious commitment and identity is a strong indicator of the x-gay homosexual population
Evaluation of Born and local effective charges in unoriented materials from vibrational spectra
We present an application of the Lorentz model in which fits to vibrational
spectra or a Kramers Kronig analysis are employed along with several useful
formalisms to quantify microscopic charge in unoriented (powdered) materials.
The conditions under which these techniques can be employed are discussed, and
we analyze the vibrational response of a layered transition metal
dichalcogenide and its nanoscale analog to illustrate the utility of this
approach.Comment: 9 pages, 1 figur
Biexcitons in two-dimensional systems with spatially separated electrons and holes
The binding energy and wavefunctions of two-dimensional indirect biexcitons
are studied analytically and numerically. It is proven that stable biexcitons
exist only when the distance between electron and hole layers is smaller than a
certain critical threshold. Numerical results for the biexciton binding
energies are obtained using the stochastic variational method and compared with
the analytical asymptotics. The threshold interlayer separation and its
uncertainty are estimated. The results are compared with those obtained by
other techniques, in particular, the diffusion Monte-Carlo method and the
Born-Oppenheimer approximation.Comment: 11 pages, 7 figure
On the physical origins of the negative index of refraction
The physical origins of negative refractive index are derived from a dilute
microscopic model, producing a result that is generalized to the dense
condensed phase limit. In particular, scattering from a thin sheet of electric
and magnetic dipoles driven above resonance is used to form a fundamental
description for negative refraction. Of practical significance, loss and
dispersion are implicit in the microscopic model. While naturally occurring
negative index materials are unavailable, ferromagnetic and ferroelectric
materials provide device design opportunities.Comment: 4 pages, 1 figur
Pressure dependence of the melting mechanism at the limit of overheating in Lennard-Jones crystals
We study the pressure dependence of the melting mechanism of a surface free
Lennard-Jones crystal by constant pressure Monte Carlo simulation. The
difference between the overheating temperature() and the
thermodynamical melting point() increase for increasing pressure. When
particles move into the repulsive part of the potential the properties at
change. There is a crossover pressure where the volume jump becomes
pressure-independent. The overheating limit is pre-announced by thermal
excitation of big clusters of defects. The temperature zone where the system is
dominated by these big clusters of defects increases with increasing pressure.
Beyond the crossover pressure we find that excitation of defects and clusters
of them start at the same temperature scale related with .Comment: 6 pages, 5 figures. Accepted for publication in Physical Review
Duality Between Spatial and Angular Shift in Optical Reflection
We report a unified representation of the spatial and angular Goos-Hanchen
and Imbert-Fedorov shifts that occur when a light beam reflects from a plane
interface. We thus reveal the dual nature of spatial and angular shifts in
optical beam reflection. In the Goos-Hanchen case we show theoretically and
experimentally that this unification naturally arises in the context of
reflection from a lossy surface (e.g., a metal).Comment: 4 pages, 3 figure
Efficient fluorescence collection from trapped ions with an integrated spherical mirror
Efficient collection of fluorescence from trapped ions is crucial for quantum
optics and quantum computing applications, specifically, for qubit state
detection and in generating single photons for ion-photon and remote ion
entanglement. In a typical setup, only a few per cent of ion fluorescence is
intercepted by the aperture of the imaging optics. We employ a simple metallic
spherical mirror integrated with a linear Paul ion trap to achieve photon
collection efficiency of at least 10% from a single Ba ion. An aspheric
corrector is used to reduce the aberrations caused by the mirror and achieve
high image quality.Comment: 5 pages and 4 figure
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