Search results for "DIPOLE"
showing 10 items of 982 documents
Experimental Constraint on Axionlike Particles over Seven Orders of Magnitude in Mass
2021
We use our recent electric dipole moment (EDM) measurement data to constrain the possibility that the HfF+ EDM oscillates in time due to interactions with candidate dark matter axionlike particles (ALPs). We employ a Bayesian analysis method which accounts for both the look-elsewhere effect and the uncertainties associated with stochastic density fluctuations in the ALP field. We find no evidence of an oscillating EDM over a range spanning from 27 nHz to 400 mHz, and we use this result to constrain the ALP-gluon coupling over the mass range 10-22-10-15 eV. This is the first laboratory constraint on the ALP-gluon coupling in the 10-17-10-15 eV range, and the first laboratory constraint to pr…
Magnetic moment of the Roper resonance
2012
The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.
Magnetic micro-droplet in rotating field: numerical simulation and comparison with experiment
2017
Magnetic droplets obtained by induced phase separation in a magnetic colloid show a large variety of shapes when exposed to an external field. However, the description of shapes is often limited. Here we formulate an algorithm based on three dimensional boundary-integral equations for strongly magnetic droplets in a high-frequency rotating magnetic field, allowing us to find their figures of equilibrium in three dimensions. The algorithm is justified by a series of comparisons with known analytical results. We compare the calculated equilibrium shapes with experimental observations and find a good agreement. The main features of these observations are the oblate-prolate transition, the flat…
Dynamics of a flexible ferromagnetic filament in a rotating magnetic field.
2017
Flexible magnetic filaments have garnered considerable attention as prospective materials for the creation of different microdevices. We describe a theoretical model of a ferromagnetic filament and derive its equations of motion by variational techniques. The numerical algorithm used to solve the filament dynamics in magnetic fields of different configurations is described. It is found that in a rotating field the filament transitions between synchronous and asynchronous regimes with respect to the rotating field, similarly to a rigid magnetic dipole. The mean angular velocity of the filament is well described by a relation valid for a rigid magnetic dipole with quantitative differences att…
Three-dimensional dynamics of a particle with a finite energy of magnetic anisotropy in a rotating magnetic field.
2013
A model of a single ferromagnetic particle with a finite coupling energy of the magnetic moment with the body of the particle is formulated, and regimes of its motion in a rotating magnetic field are investigated. Regimes are possible that are synchronous and asynchronous with the field. In a synchronous regime the easy axis of the particle is in the plane of the rotating magnetic field at low frequencies (a planar regime) and on the cone at high frequencies (a precession regime). The stability of these regimes is investigated, and it is shown that the precession regime is stable for field strengths below the critical value. In a particular range of field strength value, irreversible jumps …
Near Field of Strongly Coupled Plasmons: Uncovering Dark Modes
2012
Strongly coupled plasmons in a system of individual gold nanoparticles placed at subnanometer distance to a gold film (nanoparticle-on-plane, NPOP) are investigated using two complementary single particle spectroscopy techniques. Optical scattering spectroscopy exclusively detects plasmon modes that couple to the far field via their dipole moment (bright modes). By using photoemission electron microscopy (PEEM), we detect in the identical NPOPs near-field modes that do not couple to the scattered far field (dark modes) and are characterized by a strongly enhanced nonlinear electron emission process. To our knowledge, this is the first time that both far- and near-field spectroscopy are carr…
Double modulation sideband spectroscopy: μ0, μ24, and μ44 of 28SiH4
1992
Abstract The linear Stark effect within the ν 2 ν 4 dyad of the main isotopomer of silane, 28 SiH 4 , has been investigated by applying the saturation technique as well as IR-IR double resonance. From 35 transitions, two vibration-induced dipole moment parameters and the centrifugal distortion moment have been determined as μ 0 = 1.357(12) × 10 −5 D, μ 24 = 2.391(31) × 10 −2 D, and μ 44 = −1.261(17) × 10 −2 D employing the Stark coefficients calculated by the procedure of Loete.
29SiH4 and 30SiH4: Dipole moment parameters of the dyad from Stark effect observations with laser sidebands
1990
Abstract The linear Stark effect within the ν 2 ν 4 dyad of 29SiH4 and 30SiH4 has been investigated by applying the infrared sideband technique at microwave modulation frequencies. Two vibration-induced dipole moment parameters have been measured for each isotopomer on natural abundance samples.
Numerical study of the primitive equations in the small viscosity regime
2018
In this paper we study the flow dynamics governed by the primitive equations in the small viscosity regime. We consider an initial setup consisting on two dipolar structures interacting with a no slip boundary at the bottom of the domain. The generated boundary layer is analyzed in terms of the complex singularities of the horizontal pressure gradient and of the vorticity generated at the boundary. The presence of complex singularities is correlated with the appearance of secondary recirculation regions. Two viscosity regimes, with different qualitative properties, can be distinguished in the flow dynamics.
First Assignment and Line Strengths of the 4ν4 Band of 12CH4 near 1.9 μm
2001
Abstract The investigation of the methane spectrum in the region 1.6–2 μm has provided the first assignment and analysis of the 4ν 4 band near 1.9 μm. Hamiltonian and dipole moment operators written in tetrahedral formalism and adapted to the extrapolation method have been used to fit the spectra recorded at the Kitt Peak National Observatory/National Solar Observatory. Nearly 190 line positions and 160 measured intensities have been modeled with standard deviations of 0.107 cm −1 and 18.5%, respectively.