991 research outputs found
Precision polarimetry with real-time mitigation of optical-window birefringence
Optical-window birefringence is frequently a major obstacle in experiments
measuring changes in the polarization state of light traversing a sample under
investigation. It can contribute a signal indistinguishable from that due to
the sample and complicate the analysis. Here, we explore a method to measure
and compensate for the birefringence of an optical window using the reflection
from the last optical surface before the sample. We demonstrate that this
arrangement can cancel out false signals due to the optical-window
birefringence-induced ellipticity drift to about 1%, for the values of total
ellipticity less than 0.25 rad
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
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
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
On the sensitivity of condensed-matter P- and T-violation experiments
Experiments searching for parity- and time-reversal-invariance-violating
effects that rely on measuring magnetization of a condensed-matter sample
induced by application of an electric field are considered. A limit on
statistical sensitivity arises due to random fluctuations of the spins in the
sample. The scaling of this limit with the number of spins and their relaxation
time is derived. Application to an experiment searching for nuclear Schiff
moment in a ferroelectric is discussed.Comment: 6 pages, no 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
AC Hopping Magnetotransport Across the Spin Flop Transition in Lightly Doped La_2CuO_4
The weak ferromagnetism present in insulating La_{2}CuO_4 at low doping leads
to a spin flop transition, and to transverse (interplane) hopping of holes in a
strong external magnetic field. This results in a dimensional crossover 2D
3D for the in-plane transport, which in turn leads to an increase of the
hole's localization length and increased conduction. We demonstrate
theoretically that as a consequence of this mechanism, a frequency-dependent
jump of the in-plane ac hopping conductivity occurs at the spin flop
transition. We predict the value and the frequency dependence of the jump.
Experimental studies of this effect would provide important confirmation of the
emerging understanding of lightly doped insulating La_{2-x}Sr_xCuO_4.Comment: 4 pages, 1 figur
- …