Search results for "angular momentum"
showing 10 items of 305 documents
Evaluation of multiple-scattering contribution in extended X-ray absorption fine structure for MO4 and MO6 clusters
1994
Abstract We present a theoretical ab initio evaluation of the multiple-scattering contribution in the extended X-ray absorption fine structure for MO4 and MO6 clusters with M = Mg, Ca, Mn, Zn, Se, Sr, Mo, Ag, Te, Ba, Nd, Tb, W, Au or Bi. The dependence of the multiple-scattering signal on the absorber type, the photoelectron angular momentum and the local distortion is discussed. It is shown that the multiple-scattering contribution is significant in the photoelectron wave-vector range up to 6–7 A−1 and strongly depends on both the path geometry and the atomic species involved in the scattering process.
Current-induced domain wall motion in nanoscale ferromagnetic elements
2011
The manipulation of a magnetic domain wall (DW) by a spin polarized current in ferromagnetic nanowires has attracted tremendous interest during the last years due to fundamental questions in the fields of spin dependent transport phenomena and magnetization dynamics but also due to promising applications, such as DW based magnetic memory concepts and logic devices. We comprehensively review recent developments in the field of geometrically confined domain walls and in particular current induced DW dynamics. We focus on the influence of the magnetic and electronic transport properties of the materials on the spin transfer effect in DWs. After considering the different DW structures in ferrom…
Efficient polarization of high-angular-momentum systems
2016
We propose methods of optical pumping that are applicable to open, high-angular-momentum transitions in atoms and molecules, for which conventional optical pumping would lead to significant population loss. Instead of applying circularly polarized cw light, as in conventional optical pumping, we propose to use techniques for coherent population transfer (e.g., adiabatic fast passage) to arrange the atoms so as to increase the entropy removed from the system with each spontaneous decay from the upper state. This minimizes the number of spontaneous-emission events required to produce a stretched state, thus reducing the population loss due to decay to other states. To produce a stretched stat…
Heat Capacity of Mesoscopic Superconducting Disks
1999
We study the heat capacity of isolated giant vortex states, which are good angular momentum ($L$) states, in a mesoscopic superconducting disk using the Ginzburg-Landau (GL) theory. At small magnetic fields the $L$=0 state qualitatively behaves like the bulk sample characterized by a discontinuity in heat capacity at $T_c$. As the field is increased the discontinuity slowly turns into a continuous change which is a finite size effect. The higher $L$ states show a continuous change in heat capacity at $T_c$ at all fields. We also show that for these higher $L$ states, the behavior of the peak position with change in field is related to the paramagnetic Meissner effect (irreversible) and can …
Unified description of 2+_1 states within the deformed quasiparticle random-phase approximation
2013
We describe low-lying collective states in deformed even-even nuclei within a deformed quasiparticle random-phase approximation (dQRPA) by using a single-particle basis with good angular momentum. The statistical factors, accounting for the level occupancy, appear in the dQRPA in a natural way as rotation coefficients that take the intrinsic system to the laboratory system. We have used our model by performing a systematic analysis of E2 transitions from the first ${2}^{+}$ state to the ground state for all superfluid nuclei in the range $50lZ\ensuremath{\le}100$ by using a common charge polarization parameter $\ensuremath{\chi}=0.2$. In spite of its similarity to the QRPA, this method is a…
The Nuclear Mean Field and Many-Nucleon Configurations
2007
After the two preceding chapters, throughout impregnated with messy-looking, though necessary mathematics, we are finally entering the realm of basic concepts of nuclear structure physics. While the preceding chapters may have been a shock to the reader not familiar with the fine details of angular momentum coupling, the present chapter should offer a soothing soft landing to the basic philosophy behind the nuclear shell model, namely the nuclear mean field.
Relation between quasirigidity andL-rigidity in space-times of constant curvature and weak fields
1997
The relation between quasirigidity andL-rigidity in space-times of constant nonzero curvature and in space-times with small curvature (weak fields) is studied. The covariant expansion of bitensors about a point is considered. We obtain an increase in the order of magnitude, underL-rigidity conditions, of the rate of change with respect to a comoving orthonormal frame of the linear momentum, angular momentum, and reduced multipole moments of the energy-momentum tensor. Thus,L-rigidity leads to quasirigidity in such space-times.
A comparative account of quantum dynamics of the H+ + H2 reaction at low temperature on two different potential energy surfaces
2014
Rotationally resolved reaction probabilities, integral cross sections, and rate constant for the H+ + H2 (v = 0, j = 0 or 1) → H2 (v′ = 0, j′) + H + reaction are calculated using a time-independent quantum mechanical method and the potential energy surface of Kamisaka et al. [J. Chem. Phys.116, 654 (2002)] (say KBNN PES). All partial wave contributions of the total angular momentum, J, are included to obtain converged cross sections at low collision energies and rate constants at low temperatures. In order to test the accuracy of the KBNN PES, the results obtained here are compared with those obtained in our earlier work [P. Honvault et al. , Phys. Rev. Lett.107, 023201 (2011)] using the ac…
Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network
2019
Gravitational wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event was detected in this sear…
Orientation-Dependent Handedness of Chiral Plasmons on Nanosphere Dimers: How to Turn a Right Hand into a Left Hand
2016
Optical activity, which is used as a discriminator of chiral enantiomers, is demonstrated to be orientation dependent on individual, and nominally achiral, plasmonic nanosphere dimers. Through measurements of their giant Raman optical activity, we demonstrate that L/R-handed enantiomers can be continuously turned into their R/L-handed mirror images without passing through an achiral state. The primitive uniaxial multipolar response, with demonstrable broken parity and time reversal symmetry, reproduces the observations as resonant Raman scattering on plasmons that carry angular momentum. The analysis underscores that chirality does not have a quantitative continuous measure and recognizes t…