5,928 research outputs found
Motional sidebands and direct measurement of the cooling rate in the resonance fluorescence of a single trapped ion
Resonance fluorescence of a single trapped ion is spectrally analyzed using a
heterodyne technique. Motional sidebands due to the oscillation of the ion in
the harmonic trap potential are observed in the fluorescence spectrum. From the
width of the sidebands the cooling rate is obtained and found to be in
agreement with the theoretical prediction.Comment: 4 pages, 4 figures. Final version after minor changes, 1 figure
replaced; to be published in PRL, July 10, 200
Accurate quantification of selenoproteins in human plasma/serum by isotope dilution ICP-MS : focus on selenoprotein P
Acknowledgements The research leading to these results was funded by the EMRP Joint Research Project “Metrology for metalloproteins” (HLT-05 2012). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.Peer reviewedPostprin
Iterated Binomial Sums and their Associated Iterated Integrals
We consider finite iterated generalized harmonic sums weighted by the
binomial in numerators and denominators. A large class of these
functions emerges in the calculation of massive Feynman diagrams with local
operator insertions starting at 3-loop order in the coupling constant and
extends the classes of the nested harmonic, generalized harmonic and cyclotomic
sums. The binomially weighted sums are associated by the Mellin transform to
iterated integrals over square-root valued alphabets. The values of the sums
for and the iterated integrals at lead to new
constants, extending the set of special numbers given by the multiple zeta
values, the cyclotomic zeta values and special constants which emerge in the
limit of generalized harmonic sums. We develop
algorithms to obtain the Mellin representations of these sums in a systematic
way. They are of importance for the derivation of the asymptotic expansion of
these sums and their analytic continuation to . The
associated convolution relations are derived for real parameters and can
therefore be used in a wider context, as e.g. for multi-scale processes. We
also derive algorithms to transform iterated integrals over root-valued
alphabets into binomial sums. Using generating functions we study a few aspects
of infinite (inverse) binomial sums.Comment: 62 pages Latex, 1 style fil
Benefits of Artificially Generated Gravity Gradients for Interferometric Gravitational-Wave Detectors
We present an approach to experimentally evaluate gravity gradient noise, a
potentially limiting noise source in advanced interferometric gravitational
wave (GW) detectors. In addition, the method can be used to provide sub-percent
calibration in phase and amplitude of modern interferometric GW detectors.
Knowledge of calibration to such certainties shall enhance the scientific
output of the instruments in case of an eventual detection of GWs. The method
relies on a rotating symmetrical two-body mass, a Dynamic gravity Field
Generator (DFG). The placement of the DFG in the proximity of one of the
interferometer's suspended test masses generates a change in the local
gravitational field detectable with current interferometric GW detectors.Comment: 16 pages, 4 figure
Manipulation of Cold Atomic Collisions by Cavity QED Effects
We show how the dynamics of collisions between cold atoms can be manipulated
by a modification of spontaneous emission times. This is achieved by placing
the atomic sample in a resonant optical cavity. Spontaneous emission is
enhanced by a combination of multiparticle entanglement together with a higher
density of modes of the modified vacuum field, in a situation akin to
superradiance. A specific situation is considered and we show that this effect
can be experimentally observed as a large suppression in trap-loss rates.Comment: RevTex, 2 EPS figures; scheduled for Phys. Rev. Lett. 19 Feb 01, with
minor change
Atomic multipole relaxation rates near surfaces
The spontaneous relaxation rates for an atom in free space and close to an
absorbing surface are calculated to various orders of the electromagnetic
multipole expansion. The spontaneous decay rates for dipole, quadrupole and
octupole transitions are calculated in terms of their respective primitive
electric multipole moments and the magnetic relaxation rate is calculated for
the dipole and quadrupole transitions in terms of their respective primitive
magnetic multipole moments. The theory of electromagnetic field quantization in
magnetoelectric materials is used to derive general expressions for the decay
rates in terms of the dyadic Green function. We focus on the decay rates in
free space and near an infinite half space. For the decay of atoms near to an
absorbing dielectric surface we find a hierarchy of scaling laws depending on
the atom-surface distance z.Comment: Updated to journal version. 16 page
Guiding neutral atoms around curves with lithographically patterned current-carrying wires
Laser-cooled neutral atoms from a low-velocity atomic source are guided via a
magnetic field generated between two parallel wires on a glass substrate. The
atoms bend around three curves, each with a 15-cm radius of curvature, while
traveling along a 10-cm-long track. A maximum flux of 2*10^6 atoms/sec is
achieved with a current density of 3*10^4 A/cm^2 in the
100x100-micrometer-cross-section wires. The kinetic energy of the guided atoms
in one transverse dimension is measured to be 42 microKelvin.Comment: 9 page
Intergroup conflict management strategies from a nobel peace laureate: The case of Jose Ramos-Horta
We report on the case of Dr. José Ramos-Horta (JRH), a 1996 Nobel Peace Laureate, former President of East Timor, and current envoy of the United Nations to Guinea-Bissau. JRH agreed to an interview detailing the peace building strategies he has used to manage conflicts. The transcript of his Nobel Laureate acceptance speech was also analysed to strengthen the overall narrative. Our findings suggest two higher-order themes: (1) psycho-social skills, and (2) social networking. Specifically, JRH uses active listening, mindful breaks, and awareness of media trends to create personal and strategic networking contacts, which are critical elements in managing conflict
Probing orbital ordering in LaVO epitaxial films by Raman scattering
Single crystals of Mott-Hubbard insulator LaVO3 exhibit spin and orbital ordering along with a structural change below ≈140 K. The occurrence of orbital ordering in epitaxial LaVO3films has, however, been little investigated. By temperature-dependent Raman scatteringspectroscopy, we probed and evidenced the transition to orbital ordering in epitaxial LaVO3film samples fabricated by pulsed-laser deposition. This opens up the possibility to explore the influence of different epitaxial strain (compressive vs. tensile) and of epitaxy-induced distortions of oxygen octahedra on the orbital ordering, in epitaxial perovskite vanadate films
Geophysical studies with laser-beam detectors of gravitational waves
The existing high technology laser-beam detectors of gravitational waves may
find very useful applications in an unexpected area - geophysics. To make
possible the detection of weak gravitational waves in the region of high
frequencies of astrophysical interest, ~ 30 - 10^3 Hz, control systems of laser
interferometers must permanently monitor, record and compensate much larger
external interventions that take place in the region of low frequencies of
geophysical interest, ~ 10^{-5} - 3 X 10^{-3} Hz. Such phenomena as tidal
perturbations of land and gravity, normal mode oscillations of Earth,
oscillations of the inner core of Earth, etc. will inevitably affect the
performance of the interferometers and, therefore, the information about them
will be stored in the data of control systems. We specifically identify the
low-frequency information contained in distances between the interferometer
mirrors (deformation of Earth) and angles between the mirrors' suspensions
(deviations of local gravity vectors and plumb lines). We show that the access
to the angular information may require some modest amendments to the optical
scheme of the interferometers, and we suggest the ways of doing that. The
detailed evaluation of environmental and instrumental noises indicates that
they will not prevent, even if only marginally, the detection of interesting
geophysical phenomena. Gravitational-wave instruments seem to be capable of
reaching, as a by-product of their continuous operation, very ambitious
geophysical goals, such as observation of the Earth's inner core oscillations.Comment: 29 pages including 8 figures, modifications and clarifications in
response to referees' comments, to be published in Class. Quant. Gra
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