592 research outputs found
Gyroscopes based on nitrogen-vacancy centers in diamond
We propose solid-state gyroscopes based on ensembles of negatively charged
nitrogen-vacancy () centers in diamond. In one scheme, rotation of
the nitrogen-vacancy symmetry axis will induce Berry phase shifts in the electronic ground-state coherences proportional to the solid angle
subtended by the symmetry axis. We estimate sensitivity in the range of
in a 1 sensor volume using
a simple Ramsey sequence. Incorporating dynamical decoupling to suppress
dipolar relaxation may yield sensitivity at the level of . With a modified Ramsey scheme, Berry phase shifts in the
hyperfine sublevels would be employed. The projected sensitivity
is in the range of , however the smaller
gyromagnetic ratio reduces sensitivity to magnetic-field noise by several
orders of magnitude. Reaching would represent
an order of magnitude improvement over other compact, solid-state gyroscope
technologies.Comment: 3 figures, 5 page
Nonlinear magneto-optical rotation of frequency-modulated light resonant with a low-J transition
A low-light-power theory of nonlinear magneto-optical rotation of
frequency-modulated light resonant with a J=1->J'=0 transition is presented.
The theory is developed for a Doppler-free transition, and then modified to
account for Doppler broadening and velocity mixing due to collisions. The
results of the theory are shown to be in qualitative agreement with
experimental data obtained for the rubidium D1 line.Comment: 11 pages, 5 figures, v.2 edited for clarit
How do you know if you ran through a wall?
Stable topological defects of light (pseudo)scalar fields can contribute to
the Universe's dark energy and dark matter. Currently the combination of
gravitational and cosmological constraints provides the best limits on such a
possibility. We take an example of domain walls generated by an axion-like
field with a coupling to the spins of standard-model particles, and show that
if the galactic environment contains a network of such walls, terrestrial
experiments aimed at detection of wall-crossing events are realistic. In
particular, a geographically separated but time-synchronized network of
sensitive atomic magnetometers can detect a wall crossing and probe a range of
model parameters currently unconstrained by astrophysical observations and
gravitational experiments.Comment: 5 pages, 2 figure; to appear in the PR
Hyperfine-interaction- and magnetic-field-induced Bose-Einstein-statistics suppressed two-photon transitions
Two-photon transitions between atomic states of total electronic angular
momentum and are forbidden when the photons are of the same
energy. This selection rule is analogous to the Landau-Yang theorem in particle
physics that forbids decays of vector particle into two photons. It arises
because it is impossible to construct a total angular momentum
quantum-mechanical state of two photons that is permutation symmetric, as
required by Bose-Einstein statistics. In atoms with non-zero nuclear spin, the
selection rule can be violated due to hyperfine interactions. Two distinct
mechanisms responsible for the hyperfine-induced two-photon transitions are
identified, and the hyperfine structure of the induced transitions is
evaluated. The selection rule is also relaxed, even for zero-nuclear-spin
atoms, by application of an external magnetic field. Once again, there are two
similar mechanisms at play: Zeeman splitting of the intermediate-state
sublevels, and off-diagonal mixing of states with different total electronic
angular momentum in the final state. The present theoretical treatment is
relevant to the ongoing experimental search for a possible
Bose-Einstein-statistics violation using two-photon transitions in barium,
where the hyperfine-induced transitions have been recently observed, and the
magnetic-field-induced transitions are being considered both as a possible
systematic effect, and as a way to calibrate the measurement
Quantum computing with magnetic atoms in optical lattices of reduced periodicity
We investigate the feasibility of combining Raman optical lattices with a
quantum computing architecture based on lattice-confined magnetically
interacting neutral atoms. A particular advantage of the standing Raman field
lattices comes from reduced interatomic separations leading to increased
interatomic interactions and improved multi-qubit gate performance.
Specifically, we analyze a Zeeman system placed in Raman fields which exhibit periodicity. We find
that the resulting CNOT gate operations times are in the order of millisecond.
We also investigate motional and magnetic-field induced decoherences specific
to the proposed architecture
Magneto-optical rotation of spectrally impure fields and its nonlinear dependence on optical density
We calculate magneto-optical rptation of spectrally impure fileds in an
optically thick cold atmic medium. We show that the spectral impurity leads to
non-linear dependence of the rotation angle on optical density. Using our
calculations, we provide a quanttative analysis of the recent experimental
results of G. Labeyrie et al. [Phys. Rev. A 64, 033402 (2001)] using cold
Rb atoms.Comment: 6 pages, 5 Figures, ReVTeX4, Submitted to PR
Coherent population oscillations with nitrogen-vacancy color centers in diamond
We present results of our research on two-field (two-frequency) microwave
spectroscopy in nitrogen-vacancy (NV-) color centers in a diamond. Both fields
are tuned to transitions between the spin sublevels of the NV- ensemble in the
3A2 ground state (one field has a fixed frequency while the second one is
scanned). Particular attention is focused on the case where two microwaves
fields drive the same transition between two NV- ground state sublevels (ms=0
-> ms=+1). In this case, the observed spectra exhibit a complex narrow
structure composed of three Lorentzian resonances positioned at the pump-field
frequency. The resonance widths and amplitudes depend on the lifetimes of the
levels involved in the transition. We attribute the spectra to coherent
population oscillations induced by the two nearly degenerate microwave fields,
which we have also observed in real time. The observations agree well with a
theoretical model and can be useful for investigation of the NV relaxation
mechanisms.Comment: 17 page
Detection of a single cobalt microparticle with a microfabricated atomic magnetometer
We present magnetic detection of a single, 2 {\mu}m diameter cobalt
microparticle using an atomic magnetometer based on a microfabricated vapor
cell. These results represent an improvement by a factor of 105 in terms of the
detected magnetic moment over previous work using atomic magnetometers to
detect magnetic microparticles. The improved sensitivity is due largely to the
use of small vapor cells. In an optimized setup, we predict detection limits of
0.17 {\mu}m^3.Comment: 3 pages, 3 figure
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