Search results for "MAGNETIC DIPOLE"
showing 10 items of 217 documents
WMAPing the Universe: Supersymmetry, Dark Matter, Dark Energy, Proton Decay and Collider Physics
2003
In this review we discuss constraints on minimal supersymmetric models of particle physics implied by the recent astrophysical observations of WMAP. Although the prospects of detecting supersymmetry increase and 90 percent of the available MSSM parameter space can safely be reached by the sensitivity of future colliders, nevertheless we pay particular emphasis on discussing regions of the appropriate phase diagrams, which -if realized - would imply that detection of supersymmetry, at least in the context of minimal models, could be out of colliders reach. We also discuss the importance of a precise determination of the radiative corrections to the muon anomalous magnetic moment, both theore…
Theoretical evaluation of lanthanide binding tags as biomolecular handles for the organization of single ion magnets and spin qubits
2015
Lanthanoid complexes are amongst the most promising compounds both in single ion magnetism and as molecular spin qubits, but their organization remains an open problem. We propose to combine Lanthanide Binding Tags (LBTs) with recombinant proteins as a path for an extremely specific and spatially-resolved organisation of lanthanoid ions as spin qubits. We develop a new computational subroutine for the freely available code SIMPRE that allows an inexpensive estimate of quantum decoherence times and qubit–qubit interaction strengths. We use this subroutine to evaluate our proposal theoretically for 63 different systems. We evaluate their behavior as single ion magnets and estimate both decohe…
Dipole and quadrupole moments of Cu73–78 as a test of the robustness of the Z=28 shell closure near Ni78
2017
Nuclear spins and precise values of the magnetic dipole and electric quadrupole moments of the ground-states of neutron-rich $^{76-78}$Cu isotopes were measured using the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN. The nuclear moments of the less exotic $^{73,75}$Cu isotopes were re-measured with similar precision, yielding values that are consistent with earlier measurements. The moments of the odd-odd isotopes, and $^{78}_{29}$Cu ($N=49$) in particular, are used to investigate excitations of the assumed doubly-magic $^{78}$Ni core through comparisons with large-scale shell-model calculations. Despite the narrowing of the $Z=28$ shell gap between $N\sim45…
Hyperfine structure study of Tc97,98,99 in a new laser ion source for high-resolution laser spectroscopy
2020
Using a novel concept for efficient laser spectroscopy, we investigated the hyperfine splittings of three different atomic transitions in the long-lived isotopes $^{97\ensuremath{-}99}\mathrm{Tc}$. Despite the refractory character of the element technetium, sample sizes as low as ${10}^{11}$ atoms were sufficient to achieve excellent signal-to-noise ratios at a spectroscopic linewidth of less than 100 MHz. The obtained spectra were analyzed in detail, which results in a very good consistency for the extracted hyperfine parameters from the different transitions. The presented measurements provide the first hyperfine structure data for the isotopes $^{97,98}\mathrm{Tc}$ from which, in combina…
Correlation in the transition-metal-based Heusler compoundsCo2MnSiandCo2FeSi
2006
Half-metallic ferromagnets, such as the Heusler compounds with formula ${X}_{2}YZ$, are expected to show an integer value for the spin magnetic moment. In contrast to experiments, calculations give noninteger values in certain cases where the compounds are based on $X=\mathrm{Co}$. In order to explain deviations of the magnetic moment calculated for such compounds, the dependence of the electronic structure on the lattice parameter was studied theoretically. In the local density approximation (LDA), the minimum total energy of ${\mathrm{Co}}_{2}\mathrm{FeSi}$ is found for the experimental lattice parameter, but the calculated magnetic moment is approximately 12% too low. In addition, half-m…
Dynamics of topological spin structures
2015
Topological spin structures that emerge from the Dzyaloshinskii-Moriya interaction (DMI), such as chiral domain walls and skyrmions have become the focus of intense investigations due to exciting physics and possible applications [1].
Large shape staggering in neutron-deficient Bi isotopes
2021
The changes in the mean-square charge radius (relative to 209Bi), magnetic dipole, and electric quadrupole moments of 187,188,189,191Bi were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in 187,188,189Big, manifested by a sharp radius increase for the ground state of 188Bi relative to the neighboring 187,189Big. A large isomer shift was also observed for 188Bim. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were…
High-resolution laser spectroscopy of Al27–32
2021
Hyperfine spectra of $^\text{27-32}$Al ($Z=13$) have been measured at the ISOLDE-CERN facility via collinear laser spectroscopy using the $3s^23p\ ^2\text{P}^\text{o} _{3/2}\rightarrow 3s^24s\ ^2\text{S}_{1/2}$ atomic transition. For the first time, mean-square charge radii of radioactive aluminum isotopes have been determined alongside the previously unknown magnetic dipole moment of $^{29}$Al and electric quadrupole moments of $^{29,30}$Al. A potentially reduced charge radius at $N=19$ may suggest an effect of the $N=20$ shell closure, which is visible in the Al chain, contrary to other isotopic chains in the $sd$ shell. The experimental results are compared to theoretical calculations in…
The g-factor of the Electron Bound in Hydrogen-like Ions
1999
The experimental determination of the magnetic moment (g-factor) of the electron bound in hydrogen-like ions represents a clean test of Quantum Electrodynamics, because it is not very sensitive to nuclear structure effects. Experimental data on the g-factor of the bound electron are available only for the hydrogen atom and the 4He+-ion. In this paper we present the first result for the g-factor of hydrogen-like carbon (12C5+). The experimental accuracy is high enough to verify the relativistic contribution to the g-factor on the 10-3 level.
Highly charged ions, quantum-electrodynamics, and the electron mass
2006
Abstract High precision experiments on the magnetic moment of hydrogen-like ions confined in a Penning trap have provided the most stringent test of bound-state quantum-electrodynamic calculations. Experiments have been performed on single C 5+ and O 7+ ions. These experiments are briefly reviewed and prospects for future improvements and extension to other systems are discussed.