1,130 research outputs found
Screening and finite size corrections to the octupole and Schiff moments
Parity (P) and time reversal (T) violating nuclear forces create P, T -odd
moments in expansion of the nuclear electrostatic potential. We derive
expression for the nuclear electric octupole field which includes the electron
screening correction (similar to the screening term in the Schiff moment). Then
we calculate the Z alpha corrections to the Schiff moment which appear due to
the finite nuclear size. Such corrections are important in heavy atoms with
nuclear charge Z > 50. The Schiff and octupole moments induce atomic electric
dipole moments (EDM) and P, T -odd interactions in molecules which are measured
in numerous experiments to test CP-violation theories
Extension of the Schiff theorem to ions and molecules
According to the Schiff theorem the nuclear electric dipole moment (EDM) is
screened in neutral atoms. In ions this screening is incomplete. We extend a
derivation of the Schiff theorem to ions and molecules. The finite nuclear size
effects are considered including Z^2 alpha^2 corrections to the nuclear Schiff
moment which are significant in all atoms and molecules of experimental
interest. We show that in majority of ionized atoms the nuclear EDM
contribution to the atomic EDM dominates while in molecules the contribution of
the Schiff moment dominates. We also consider the screening of electron EDM in
ions
Calculation of P,T-odd electric dipole moments for diamagnetic atoms Xe, Yb, Hg, Rn, and Ra
Electric dipole moments of diamagnetic atoms of experimental interest are
calculated using the relativistic Hartree-Fock and random-phase approximation
methods, the many-body perturbation theory and configuration interaction
technique. We consider P,T-odd interactions which give rise to atomic electric
dipole moment in the second order of the perturbation theory. These include
nuclear Schiff moment, P,T-odd electron-nucleon interaction and electron
electric dipole moment. Interpretation of a new experimental constraint of a
permanent electric dipole moment of Hg [W. C. Griffith {\it et al.},
Phys. Rev. Lett. {\bf 102}, 101601 (2009)] is discussed.Comment: 9 page
Scalar multi-wormholes
In 1921 Bach and Weyl derived the method of superposition to construct new
axially symmetric vacuum solutions of General Relativity. In this paper we
extend the Bach-Weyl approach to non-vacuum configurations with massless scalar
fields. Considering a phantom scalar field with the negative kinetic energy, we
construct a multi-wormhole solution describing an axially symmetric
superposition of wormholes. The solution found is static, everywhere
regular and has no event horizons. These features drastically tell the
multi-wormhole configuration from other axially symmetric vacuum solutions
which inevitably contain gravitationally inert singular structures, such as
`struts' and `membranes', that keep the two bodies apart making a stable
configuration. However, the multi-wormholes are static without any singular
struts. Instead, the stationarity of the multi-wormhole configuration is
provided by the phantom scalar field with the negative kinetic energy. Anther
unusual property is that the multi-wormhole spacetime has a complicated
topological structure. Namely, in the spacetime there exist
asymptotically flat regions connected by throats.Comment: 11 pages, 13 figure
Atomic electric dipole moments of He and Yb induced by nuclear Schiff moments
We have calculated the atomic electric dipole moments (EDMs) d of ^3He and
^{171}Yb induced by their respective nuclear Schiff moments S. Our results are
d(He)= 8.3x10^{-5} and d(Yb)= -1.9 in units 10^{-17}S/(e{fm}^3)e cm. By
considering the nuclear Schiff moments induced by the parity and time-reversal
violating nucleon-nucleon interaction we find d(^{171}Yb)~0.6d(^{199}Hg). For
^3He the nuclear EDM coupled with the hyperfine interaction gives a larger
atomic EDM than the Schiff moment. The result for ^3He is required for a
neutron EDM experiment that is under development, where ^3He is used as a
comagnetometer. We find that the EDM for He is orders of magnitude smaller than
the neutron EDM. The result for Yb is needed for the planning and
interpretation of experiments that have been proposed to measure the EDM of
this atom.Comment: 4 page
Nuclear Schiff moment in nuclei with soft octupole and quadrupole vibrations
Nuclear forces violating parity and time reversal invariance (-odd) produce -odd nuclear moments, for example, the
nuclear Schiff moment. In turn, this moment can induce the electric dipole
moment in the atom. The nuclear Schiff moment is predicted to be enhanced in
nuclei with static quadrupole and octupole deformation. The analogous
suggestion of the enhanced contribution to the Schiff moment from the soft
collective quadrupole and octupole vibrations in spherical nuclei is tested in
this article in the framework of the quasiparticle random phase approximation
with separable quadrupole and octupole forces applied to the odd Ra
and Rn isotopes. We confirm the existence of the enhancement effect
due to the soft modes. However, in the standard approximation the enhancement
is strongly reduced by a small weight of the corresponding "particle + phonon"
component in a complicated wave function of a soft nucleus. The perspectives of
a better description of the structure of heavy soft nuclei are discussed.Comment: 27 pages, 3 figures, minor corrections in references adde
A suggested search for 207Pb nuclear Schiff moment in PbTiO3 ferroelectric
We suggest two types of experiments, NMR and macroscopic magnetometry, with
solid PbTiO3 to search for the nuclear Schiff moment of 207Pb. Both kinds of
experiments promise substantial improvement over the presently achieved
sensitivities. Statistical considerations show that the improvement of the
current sensitivity can be up to 10 orders of magnitude for the magnetometry
experiment and up to 6 orders of magnitude for the NMR experiment. Such
significant enhancement is due to the strong internal electric field of the
ferroelectric, as well as due to the possibility to cool the nuclear-spin
subsystem in the compound down to nanokelvin temperatures.Comment: 4 pages; revised sensitivity estimate for NMR experimen
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