3,576 research outputs found

    Calculation of isotope shifts and relativistic shifts in CI, CII, CIII and CIV

    Full text link
    We present an accurate ab initio method of calculating isotope shifts and relativistic shifts in atomic spectra. We test the method on neutral carbon and three carbon ions. The relativistic shift of carbon lines may allow them to be included in analyses of quasar absorption spectra that seek to measure possible variations in the fine structure constant, alpha, over the lifetime of the Universe. Carbon isotope shifts can be used to measure isotope abundances in gas clouds: isotope abundances are potentially an important source of systematic error in the alpha-variation studies. These abundances are also needed to study nuclear reactions in stars and supernovae, and test models of chemical evolution of the Universe

    Fermi acceleration in time-dependent rectangular billiards due to multiple passages through resonances

    Full text link
    We consider a slowly rotating rectangular billiard with moving boundaries and use the canonical perturbation theory to describe the dynamics of a billiard particle. In the process of slow evolution certain resonance conditions can be satisfied. Correspondingly, phenomena of scattering on a resonance and capture into a resonance happen in the system. These phenomena lead to destruction of adiabatic invariance and to unlimited acceleration of the particle.Comment: 20 pages. Presented on School-Conference "Mathematics and Physics of Billiard-Like Systems" (Ubatuba, 2011). Accepted to Chao

    Enhancement of the electric dipole moment of the electron in PbO

    Full text link
    The a(1) state of PbO can be used to measure the electric dipole moment of the electron d_e. We discuss a semiempirical model for this state, which yields an estimate of the effective electric field on the valence electrons in PbO. Our final result is an upper limit on the measurable energy shift, which is significantly larger than was anticipated earlier: 2Wdde2.4×1025Hz[deecm] 2|W_d|d_e \ge 2.4\times 10^{25} \textrm{Hz} [ \frac{d_e}{e \textrm{cm}} ].Comment: 4 pages, revtex4, no figures, submitted to PR

    Using Molecules to Measure Nuclear Spin-Dependent Parity Violation

    Full text link
    Nuclear spin-dependent parity violation arises from weak interactions between electrons and nucleons, and from nuclear anapole moments. We outline a method to measure such effects, using a Stark-interference technique to determine the mixing between opposite-parity rotational/hyperfine levels of ground-state molecules. The technique is applicable to nuclei over a wide range of atomic number, in diatomic species that are theoretically tractable for interpretation. This should provide data on anapole moments of many nuclei, and on previously unmeasured neutral weak couplings

    Constants of Geodesic Motion in Higher-Dimensional Black-Hole Spacetimes

    Full text link
    In [arXiv:hep-th/0611083] we announced the complete integrability of geodesic motion in the general higher-dimensional rotating black-hole spacetimes. In the present paper we prove all the necessary steps leading to this conclusion. In particular, we demonstrate the independence of the constants of motion and the fact that they Poisson commute. The relation to a different set of constants of motion constructed in [arXiv:hep-th/0612029] is also briefly discussed.Comment: 8 pages, no figure

    Complete Integrability of Geodesic Motion in General Kerr-NUT-AdS Spacetimes

    Full text link
    We explicitly exhibit n-1 constants of motion for geodesics in the general D-dimensional Kerr-NUT-AdS rotating black hole spacetime, arising from contractions of even powers of the 2-form obtained by contracting the geodesic velocity with the dual of the contraction of the velocity with the (D-2)-dimensional Killing-Yano tensor. These constants of motion are functionally independent of each other and of the D-n+1 constants of motion that arise from the metric and the D-n = [(D+1)/2] Killing vectors, making a total of D independent constants of motion in all dimensions D. The Poisson brackets of all pairs of these D constants are zero, so geodesic motion in these spacetimes is completely integrable.Comment: 4 pages. We have now found that the geodesic motion is not just integrable, but completely integrabl

    Effect of long-term creep on microstructure of a 9% Cr heat resistant steel

    Get PDF
    The effect of long-term creep at 600°C under 137 MPa on the microstructure of a P92- type steel was investigated. The microstructure after tempering consisted of laths with an average thickness of 400 nm. Dispersion of secondary phases consists of M₂₃C₆ carbides with an average size of 85 nm located mainly on lath, block and prior austenite boundaries and MX carbonitrides with average size of 31 nm homogeniously distributed throughou

    Some forgotten features of the Bose Einstein Correlations

    Full text link
    Notwithstanding the visible maturity of the subject of Bose-Einstein Correlations (BEC), as witnessed nowadays, we would like to bring to ones attention two points, which apparently did not received attention they deserve: the problem of the choice of the form of C2(Q)C_2(Q) correlation function when effects of partial coherence of the hadronizing source are to be included and the feasibility to model effects of Bose-Einstein statistics, in particular the BEC, by direct numerical simulations.Comment: Talk delivered by G.Wilk at the International Workshop {\it Relativistic Nuclear Physics: from Nuclotron to LHC energies}, Kiev, June 18-22, 2007, Ukraine; misprints correcte

    Difference between radiative transition rates in atoms and antiatoms

    Full text link
    We demonstrate that CP violation results in a difference of the partial decay rates of atoms and antiatoms. The magnitude of this difference is estimated.Comment: 5 pages, 5 figure
    corecore