4,932 research outputs found
Sympathetic Cooling of Trapped Cd+ Isotopes
We sympathetically cool a trapped 112Cd+ ion by directly Doppler-cooling a
114Cd+ ion in the same trap. This is the first demonstration of optically
addressing a single trapped ion being sympathetically cooled by a different
species ion. Notably, the experiment uses a single laser source, and does not
require strong focusing. This paves the way toward reducing decoherence in an
ion trap quantum computer based on Cd+ isotopes.Comment: 4 figure
Ion-neutral sympathetic cooling in a hybrid linear rf Paul and magneto-optical trap
Long range polarization forces between ions and neutral atoms result in large
elastic scattering cross sections, e.g., 10^6 a.u. for Na+ on Na or Ca+ on Na
at cold and ultracold temperatures. This suggests that a hybrid ion-neutral
trap should offer a general means for significant sympathetic cooling of atomic
or molecular ions. We present SIMION 7.0 simulation results concerning the
advantages and limitations of sympathetic cooling within a hybrid trap
apparatus, consisting of a linear rf Paul trap concentric with a Na
magneto-optical trap (MOT). This paper explores the impact of various heating
mechanisms on the hybrid system and how parameters related to the MOT, Paul
trap, number of ions, and ion species affect the efficiency of the sympathetic
cooling
Molecular Dynamics Simulation of Sympathetic Crystallization of Molecular Ions
It is shown that the translational degrees of freedom of a large variety of
molecules, from light diatomic to heavy organic ones, can be cooled
sympathetically and brought to rest (crystallized) in a linear Paul trap. The
method relies on endowing the molecules with an appropriate positive charge,
storage in a linear radiofrequency trap, and sympathetic cooling. Two
well--known atomic coolant species, and
, are sufficient for cooling the molecular mass range
from 2 to 20,000 amu. The large molecular charge required for simultaneous
trapping of heavy molecules and of the coolant ions can easily be produced
using electrospray ionization. Crystallized molecular ions offer vast
opportunities for novel studies.Comment: Accepted for publication in Phys. Rev.
Sympathetic cooling of He ions in a radiofrequency trap
We have generated Coulomb crystals of ultracold He ions in a linear
radiofrequency trap, by sympathetic cooling via laser--cooled Be.
Stable crystals containing up to 150 localized He ions at 20 mK were
obtained. Ensembles or single ultracold He ions open up interesting
perspectives for performing precision tests of QED and measurements of nuclear
radii. The present work also indicates the feasibility of cooling and
crystallizing highly charged atomic ions using Be as coolant.Comment: 4 pages, 2 figure
Sympathetic Cooling Simulations with a Variable Time Step
In this paper we present a new variable time step criterion for the
velocity-Verlet algorithm allowing to correctly simulate the dynamics of
charged particles exchanging energy via Coulomb collisions while minimising
simulation time. We present physical arguments supporting the use of the
criterion along with numerical results proving its validity. We numerically
show that ions with 18 meV initial energy can be
captured and sympathetically cooled by a Coulomb crystal of
and in less than 10 ms, an important result for the GBAR
project.Comment: LEAP 2016 proceedin
Sympathetic Cooling of Mixed Species Two-Ion Crystals for Precision Spectroscopy
Sympathetic cooling of trapped ions has become an indispensable tool for
quantum information processing and precision spectroscopy. In the simplest
situation a single Doppler-cooled ion sympathetically cools another ion which
typically has a different mass. We analytically investigate the effect of the
mass ratio of such an ion crystal on the achievable temperature limit in the
presence of external heating. As an example, we show that cooling of a single
Al+ with Be+, Mg+ and Ca+ ions provides similar results for heating rates
typically observed in ion traps, whereas cooling ions with a larger mass
perform worse. Furthermore, we present numerical simulation results of the
rethermalisation dynamics after a background gas collision for the Al+/Ca+
crystal for different cooling laser configurations.Comment: Made Graphics black & white print compatible, clarified abstract and
summar
Sympathetic ground state cooling and coherent manipulation with two-ion-crystals
We have cooled a two-ion-crystal to the ground state of its collective modes
of motion. Laser cooling, more specific resolved sideband cooling is performed
sympathetically by illuminating only one of the two Ca ions in the
crystal. The heating rates of the motional modes of the crystal in our linear
trap have been measured, and we found them considerably smaller than those
previously reported by Q. Turchette {\em et. al.} Phys. Rev. A 61, 063418
(2000) in the case of trapped Be ions. After the ground state is
prepared, coherent quantum state manipulation of the atomic population can be
performed. Within the coherence time, up to 12 Rabi oscillations are observed,
showing that many coherent manipulations can be achieved. Coherent excitation
of each ion individually and ground state cooling are important tools for the
realization of quantum information processing in ion traps
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