2,062 research outputs found
On the structure and spectrum of classical two-dimensional clusters with a logarithmic interaction potential
We present a numerical study of the effect of the repulsive logarithmic
inter-particle interaction on the ground state configuration and the frequency
spectrum of a confined classical two-dimensional cluster containing a finite
number of particles. In the case of a hard wall confinement all particles form
one ring situated at the boundary of the potential. For a general r^n
confinement potential, also inner rings can form and we find that all
frequencies lie below the frequency of a particular mode, namely the
breathing-like mode. An interesting situation arises for the parabolic confined
system(i.e. n=2). In this case the frequency of the breathing mode is
independent of the number of particles leading to an upper bound for all
frequencies. All results can be understood from Earnshaw's theorem in two
dimensions. In order to check the sensitivity of these results, the spectrum of
vortices in a type II superconductor which, in the limit of large penetration
depths, interact through a logarithmic potential, is investigated.Comment: 11 pages, 6 figure
Objectification in Action: Self- and Other-Objectification in Mixed-Sex Interpersonal Interactions
Although the process of sexual objectification is theorized to occur within interpersonal interactions, we believe this is the first study to examine sexual objectification and self-objectification in actual (nonconfederate) interpersonal encounters. Men and women were brought into the laboratory and interacted in mixed-sex dyads. We used dyadic analysis to detect whether partners’ objectification of each other affected state self-objectification, and the resulting feelings of comfort and authenticity during the interaction. After the interaction, participants completed a cognitive performance task, a measure of career aspirations, and a measure of relationship agency. Results showed that for women only, being objectified by their male interaction partner was associated with an increase in state self-objectification, and state self-objectification led to perceptions that the interaction was less comfortable and less authentic. Furthermore, for women but not for men, having authentic interactions was found to relate positively to relationship agency, career aspirations, and cognitive performance. This research shows that self-objectification is not only a self-process but an interpersonal process heightened by the real-time sexual objectification of a male interaction partner. Online slides for instructors who want to use this article for teaching are available to PWQ subscribers on PWQ\u27s website at http://pwq.sagepub.com/supplementa
Open/Closed String Topology and Moduli Space Actions via Open/Closed Hochschild Actions
In this paper we extend our correlation functions to the open/closed case.
This gives rise to actions of an open/closed version of the Sullivan PROP as
well as an action of the relevant moduli space. There are several unexpected
structures and conditions that arise in this extension which are forced upon us
by considering the open sector. For string topology type operations, one cannot
just consider graphs, but has to take punctures into account and one has to
restrict the underlying Frobenius algebras. In the moduli space, one first has
to pass to a smaller moduli space which is closed under open/closed duality and
then consider covers in order to account for the punctures
The Fluctuations of the Quark Number and of the Chiral Condensate
The distributions of the quark number and chiral condensate over the gauge
fields are computed for QCD in Euclidean space at nonzero quark chemical
potential. As both operators are non-hermitian the distributions are in the
complex plane. Moreover, because of the sign problem, the distributions are not
real and positive. The computations are carried out within leading order chiral
perturbation theory and give a direct insight into the delicate cancellations
that take place in contributions to the total baryon number and the chiral
condensate.Comment: 19 pages, 2 figure
Anomalous temperature dependence of surface tension and capillary waves at liquid gallium
The temperature dependence of surface tension \gamma(T) at liquid gallium is
studied theoretically and experimentally using light scattering from capillary
waves. The theoretical model based on the Gibbs thermodynamics relates the
temperature derivative of \gamma to the surface excess entropy -\Delta S.
Although capillary waves contribute to the surface entropy with a positive sign
the effect of dipole layer on \Delta S is negative. Experimental data collected
at a free Ga surface in the temperature range from 30 to 160 C show that the
temperature derivative of the tension changes sign near 100 C.Comment: 11 pages, 1 Postscript figure, submitted to J. Phys.
Topology of six degrees of freedom magnetic bearing
A novel magnetic topology has been designed for a six degrees of freedom, magnetically levitated and driven mirror, to be used in a three dimensional (3D) measurement system based on laser interferometry. The translations of the mirror are to be kept small, whereas the rotations are to be controlled over a large range with a high bandwidth and high accuracy. Finite element modelling (FEM) is used to analyze the proposed topology. For computational load reduction, a 2D FEM model has been derived from the actual 3D topology, which incorporates most of the magnetic subsystems. Simulations show that cross-influence between the actuators is small, that the forces and torques are proportional to the applied currents and that the angle of the rotor is of little influence. This allows the multiple in multiple out system to be regarded as multiple linear single in single out systems. ©2000 American Institute of Physics
Membranes in the two-Higgs standard model
We present some non-topological static wall solutions in two-Higgs extensions
of the standard model. They are classically stable in a large region of
parameter space, compatible with perturbative unitarity and with present
phenomenological bounds.Comment: 7 pages, latex, 3 figures available upon reques
Scattering off an SO(10) cosmic string
The scattering of fermions from the abelian string arising during the phase
transition induced by the Higgs in the
126 representation is studied. Elastic cross-sections and baryon number
violating cross-sections due to the coupling to gauge fields in the core of the
string are computed by both a first quantised method and a perturbative second
quantised method. The elastic cross-sections are found to be Aharonov-Bohm
type. However, there is a marked asymmetry between the scattering
cross-sections for left and right handed fields. The catalysis cross-sections
are small, depending on the grand unified scale. If cosmic strings were
observed our results could help tie down the underlying gauge group.Comment: 20 page
Double-impulse magnetic focusing of launched cold atoms.
We have theoretically investigated three-dimensional focusing of a launched cloud of cold atoms using a pair of magnetic lens pulses (the alternate-gradient method). Individual lenses focus radially and defocus axially or vice versa. The performance of the two possible pulse sequences are compared and found to be ideal for loading both 'pancake' and 'sausage' shaped magnetic/optical microtraps. It is shown that focusing aberrations are considerably smaller for double-impulse magnetic lenses compared to single-impulse magnetic lenses. An analysis of clouds focused by the double-impulse technique is presented
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