Search results for "polarization [photon]"
showing 10 items of 39 documents
System for control of polarization state of light and generation of light with continuously rotating linear polarization
2019
We present a technique for generating light in an arbitrary polarization state. The technique is based on interference of two orthogonally polarized light beams, whose amplitudes and phases are controlled with a Mach-Zehnder inteferometer with acousto-optic modulators (AOMs) placed in each arm. We demonstrate that via control over amplitudes, phases, and frequencies of acoustic waves driving the AOMs, any polarization state can be synthesized. In particular, we demonstrate generation of linearly polarized light, whose polarization plane continuously rotates at a rate from 1 kHz to 1 MHz. Such light finds applications in science (e.g., investigations of Bloch-Siegert effect) and technology (…
Polarization types of isogenous Prym-Tyurin varieties
2007
Let p:C-->Y be a covering of smooth, projective curves which is a composition of ��:C-->C' of degree 2 and g:C'-->Y of degree n. Let f:X-->Y be the covering of degree 2^n, where the curve X parametrizes the liftings in C^{(n)} of the fibers of g:C'-->Y. Let P(X,��) be the associated Prym-Tyurin variety, known to be isogenous to the Prym variety P(C,C'). Most of the results in the paper focus on calculating the polarization type of the restriction of the canonical polarization of JX on P(X,��). We obtain the polarization type when n=3. When Y=P^1 we conjecture that P(X,��) is isomorphic to the dual of the Prym variety P(C,C'). This was known when n=2, we prove it when n=3, and…
Modeling X-ray emission from stellar coronae
2008
By extrapolating from observationally derived surface magnetograms of low-mass stars we construct models of their coronal magnetic fields and compare the 3D field geometry with axial multipoles. AB Dor, which has a radiative core, has a very complex field, whereas V374 Peg, which is completely convective, has a simple dipolar field. We calculate global X-ray emission measures assuming that the plasma trapped along the coronal loops is in hydrostatic equilibrium and compare the differences between assuming isothermal coronae, or by considering a loop temperature profiles. Our preliminary results suggest that the non-isothermal model works well for the complex field of AB Dor, but not for the…
Electrodialysis with asymmetrically profiled membranes: Influence of profiles geometry on desalination performance and limiting current phenomena
2021
Abstract Electrodialysis (ED) has recently gained much attention in the wide field of desalination and water treatment. However, energy consumption and capital costs may impair the process competitiveness. In this regard, limiting current density (LCD) and current efficiency (η) are key performance parameters for optimized ED systems. In this work, an experimental campaign was carried out characterizing the performance of ED stacks when adopting asymmetrically profiled membranes. Current–voltage curves were recorded under different operating conditions mimicking the operation of brackish water or seawater desalination units. Results showed that there was a preferable direction of the electr…
Measurement of high energy resolution inelastic proton scattering at and close to zero degrees
2009
13 pages, 15 figures.-- Printed version published Jul 1, 2009.
Light baryons and their electromagnetic interactions in the covariant constituent quark model
2012
We extend the confined covariant constituent quark model that was previously developed by us for mesons to the baryon sector. In our numerical calculation we use the same values for the constituent quark masses and the infrared cutoff as have been previously used in the meson sector. In a first application we describe the static properties of the proton and neutron, and the $\Lambda$-hyperon (magnetic moments and charge radii) and the behavior of the nucleon form factors at low momentum transfers. We discuss in some detail the conservation of gauge invariance of the electromagnetic transition matrix elements in the presence of a nonlocal coupling of the baryons to the three constituent quar…
Polarization Observables in Deuteron Electrodisintegration
1992
The electrodisintegration of the deuteron with polarized beam and target is investigated. The additional polarization form factors (inclusive reaction) and structure functions (exclusive reaction) are discussed. The sensitivity of these form factors and structure functions to the potential model, to meson and isobar degrees of freedom, and to electromagnetic form factors is studied in different kinematical regions.
Double Polarization Observables in η Electroproduction
2009
Abstract A new measurement of beam-recoil double-polarization observables in η electroproduction at the A1 collaboration at MAMI is presented. The energy region of the S 11 ( 1525 ) resonance was covered at a four-momentum transfer of Q 2 = 0.1 GeV 2 / c 2 . It turned out, that the usual interpretation of the reaction mechanism via S 11 and D 13 resonance fails to explain the relative phase between the corresponding multipole amplitudes tested by this experiment, while the new data are still in good agreement with previous measurements.
T- and P-asymmetries in the (γ, π−) reaction on 13C and 15N
1995
Abstract A simultaneous theoretical analysis of the polarization observables for negative pion photoproduction off the 13 C and 15 N nuclei is performed. A sensitivity of the target and recoil asymmetries to different ingredients of the theory (the Fermi motion, the final state interaction and the nuclear model input) is investigated. The importance of the high (2 hω ) configurations in the nuclea ground states is shown.
Timing of accreting millisecond pulsars
2008
We review recent results from the X-ray timing of accreting millisecond pulsars in LMXBs. This is the first time a timing analysis is performed on accreting millisecond pulsars, and for the first time we can obtain information on the behavior of a very fast pulsar subject to accretion torques. We find both spin-up and spin-down behaviors, from which, using available models for the accretion torques, we derive information on the mass accretion rate and magnetic field of the neutron star in these systems. We also report here the first measure of the orbital period derivative for an accreting millisecond pulsar, derived for SAX J1808.4-3658 over a timespan of more 7 years.