Search results for "Polar"
showing 10 items of 3817 documents
Review of Lattice QCD Studies of Hadronic Vacuum Polarization Contribution to Muon g-2
2019
Lattice QCD (LQCD) studies for the hadron vacuum polarization (HVP) and its contribution to the muon anomalous magnetic moment (muon g-2) are reviewed. There currently exists more than 3-sigma deviations in the muon g-2 between the BNL experiment with 0.5 ppm precision and the Standard Model (SM) predictions, where the latter relies on the QCD dispersion relation for the HVP. The LQCD provides an independent crosscheck of the dispersive approaches and important indications for assessing the SM prediction with measurements at ongoing/forthcoming experiments at Fermilab/J-PARC (0.14/0.1 ppm precision). The LQCD has made significant progress, in particular, in the long distance and finite volu…
Quantum emitter states dressed by the plasmon modes of a metal nanoparticle in the strong coupling regim
2017
The quantum control of emitters is a key issue for quantum information processing at the nanoscale. This generally necessitates the strong coupling of emitters to a high Q-cavity for efficient manipulation of the atoms and field dynamics (cavity quantum electrodynamics or cQED). Since almost a decade, strong efforts are put to transpose cQED concepts to plasmonics in order to profit of the strong mode confinement of surface plasmons polaritons. Despite the intrinsic presence of lossy channels leading to strong decoherence in plasmonics systems, it has been experimentally proven that it is possible to reach the strong coupling regim [1].
Coherent and incoherent phonon processes in artificial atoms
2003
Carrier-phonon interaction in semiconductor quantum dots leads to three classes of phenomena: coherent effects (spectrum reconstruction) due to the nearly-dispersionless LO phonons, incoherent effects (transitions) induced by acoustical phonons and dressing phenomena, related to non-adiabatic, sub-picosecond excitation. Polaron spectra, relaxation times and dressing-related decoherence rates are calculated, in accordance with experiment.
Field-free molecular orientation of1Σand2Πmolecules at high temperature
2012
We analyze the control of field-free molecular orientation at high temperature by use of a two-color laser bipulse strategy proposed in Zhang et al. [Phys. Rev. A 83, 043410 (2011)]. A general study shows that there exist two types of linear molecules for which a different mechanism has to be used. For molecules with a large hyperpolarizability, a monochromatic laser pre-pulse is applied before the two-color laser pulse at a time close to the rotational period ${T}_{r}$, while for molecules with a small hyperpolarizability, the optimal delay is found close to ${T}_{r}/4$ or $3{T}_{r}/4$. We extend this analysis to the case of a ${}^{2}\phantom{\rule{-0.16em}{0ex}}\ensuremath{\Pi}$ molecule …
Coupling of a dipolar emitter into one-dimensional surface plasmon.
2013
Quantum plasmonics relies on a new paradigm for light-matter interaction. It benefits from strong confinement of surface plasmon polaritons (SPP) that ensures efficient coupling at a deep subwavelength scale, instead of working with a long lifetime cavity polariton that increases the duration of interaction. The large bandwidth and the strong confinement of one dimensional SPP enable controlled manipulation of a nearby quantum emitter. This paves the way to ultrafast nanooptical devices. However, the large SPP bandwidth originates from strong losses so that a clear understanding of the coupling process is needed. In this report, we investigate in details the coupling between a single emitte…
Parity violation correlations in light muonic atoms
1989
The 2 S -1 S transition in light muonic atoms is very sensitive to parity violation correlations induced via neutral currents. Observables depending on these transitions such as the photon polarization and the angular correlation between the emitted radiation and the atom polarization are a clear signal of weak neutral currents in atoms. We find the relation between the lepton and quark couplings and these observables emphasizing the effect of the nuclear spin. The results expected in muonic, atoms μ- 4 He and μ- 3 He are given.
Hadron azimuthal distributions and transverse spin asymmetries in DIS of leptons off transversely polarized targets from SMC
1999
Abstract Azimuthal distributions of hadrons (mainly π + and π − ) produced in DIS off transversely polarized targets (proton and deuteron) are studied for the first time in SMC. From these azimuthal distributions, transverse single-spin asymmetries are derived. According to Collins (‘Collins effect’), the azimuthal distribution of the leading hadron might exhibit an symmetry which originates from the transverse polarization of the final quark.
The gluon spin in the chiral bag model
2000
We study the gluon polarization contribution at the quark model renormalization scale to the proton spin, $\Gamma$, in the chiral bag model. It is evaluated by taking the expectation value of the forward matrix element of a local gluon operator in the axial gauge $A^+=0$. It is shown that the confining boundary condition for the color electric field plays an important role. When a solution satisfying the boundary condition for the color electric field, which is not the conventionally used but which we favor, is used, the $\Gamma$ has a positive value for {\it all} bag radii and its magnitude is comparable to the quark spin polarization. This results in a significant reduction in the relativ…
Transverse spin asymmetries in p ↑ p → π± + X and lp ↑ → l′ + π± + X
2000
Abstract While transverse spin effects have been studied in hadronic interactions since a few decades, investigations with leptonic probes have started very recently. Azimuthal distributions of hadrons (mainly π + and π − ) produced in DIS off transversely polarized targets (proton and deuteron) are studied for the first time in SMC. According to Collins (‘Collins effect’), the azimuthal distribution of the leading hadron might exhibit an asymmetry which originates from the transverse polarization of the final quark.
Dispersion-to-spectrum mapping in nonlinear fibers based on optical wave-breaking
2013
In this work we recognize new strategies involving optical wave-breaking for controlling the output pulse spectrum in nonlinear fibers. To this end, first we obtain a constant of motion for nonlinear pulse propagation in waveguides derived from the generalized nonlinear Schrödinger equation. In a second phase, using the above conservation law we theoretically analyze how to transfer in a simple manner the group-velocity-dispersion curve of the waveguide to the output spectral profile of pulsed light. Finally, the computation of several output spectra corroborates our proposition.