90 research outputs found
Migraine relief in 20 minutes using eyedrops?
One randomized crossover trial demonstrated the effectiveness of this simple, affordable treatment for patients with acute migraine pain.Yufei Ge, MD; Gregory Castelli, PharmD, BCPS, BC-ADM (UPMC St. Margaret Family Medicine Residency Program, Pittsburgh, PA). Deputy Editor: Anne Mounsey, MD (Department of Family Medicine, University of North Carolina, Chapel Hill)Includes bibliographical reference
Demonstration of a quantum logic gate in a cryogenic surface-electrode ion trap
We demonstrate quantum control techniques for a single trapped ion in a
cryogenic, surface-electrode trap. A narrow optical transition of Sr+ along
with the ground and first excited motional states of the harmonic trapping
potential form a two-qubit system. The optical qubit transition is susceptible
to magnetic field fluctuations, which we stabilize with a simple and compact
method using superconducting rings. Decoherence of the motional qubit is
suppressed by the cryogenic environment. AC Stark shift correction is
accomplished by controlling the laser phase in the pulse sequencer, eliminating
the need for an additional laser. Quantum process tomography is implemented on
atomic and motional states using conditional pulse sequences. With these
techniques we demonstrate a Cirac-Zoller Controlled-NOT gate in a single ion
with a mean fidelity of 91(1)%.Comment: 11 pages, 5 figures, 4 table
Laser-induced charging of microfabricated ion traps
Electrical charging of metal surfaces due to photoelectric generation of
carriers is of concern in trapped ion quantum computation systems, due to the
high sensitivity of the ions' motional quantum states to deformation of the
trapping potential. The charging induced by typical laser frequencies involved
in doppler cooling and quantum control is studied here, with microfabricated
surface electrode traps made of aluminum, copper, and gold, operated at 6 K
with a single Sr ion trapped 100 m above the trap surface. The lasers
used are at 370, 405, 460, and 674 nm, and the typical photon flux at the trap
is 10 photons/cm/sec. Charging is detected by monitoring the ion's
micromotion signal, which is related to the number of charges created on the
trap. A wavelength and material dependence of the charging behavior is
observed: lasers at lower wavelengths cause more charging, and aluminum
exhibits more charging than copper or gold. We describe the charging dynamic
based on a rate equation approach.Comment: 8 pages, 8 figure
Response of the East Asian climate system to water and heat changes of global frozen soil using NCAR CAM model
El siguiente trabajo tiene como objetivo analizar un corpus de obras poéticas publicadas en Chile durante la primera década del siglo XXI, a partir de las distintas simbolizaciones que ellas plantean en torno a dos figuras culturales que resultan claves para entender el imaginario de la letra poética actual en nuestro paÃs. Nos referimos a la casa y el niño, ambas como metáforas de una habitabilidad fracasada e, incluso, imposible, que se produce como efecto de la economÃa neoliberal, consolidada en el campo cultural chileno tras el retorno a la democracia.The following article aims to analyze a corpus of poetic productions published in Chile during the first decade of the 21st century, starting from the different symbolizations they propose around two cultural figures, that are key to understand the imaginary of nowadays poetics. Those are, the home and the child, both as symbolizations of an unsuccessful habitability, even impossible, due to the effects that the neoliberal economy has created in the Chilean cultural space, after the return of democracy.El següent treball té com a objectiu analitzar un corpus d'obres poètiques publicades a Xile durant la primera dècada del segle XXI, a partir de les diferents simbolitzacions que aquestes plantegen entorn de dues figures culturals que resulten clau per entendre l'imaginari de la lletra poètica actual al nostre paÃs. Ens referim a la casa i el nen, ambdues com a metà fores d'una habitabilitat fracassada i, fins i tot, impossible, que es produeix com a efecte de l'economia neoliberal, consolidada en el camp cultural xilè després del retorn a la democrà cia
One-dimensional array of ion chains coupled to an optical cavity
We present a novel hybrid system where an optical cavity is integrated with a
microfabricated planar-electrode ion trap. The trap electrodes produce a
tunable periodic potential allowing the trapping of up to 50 separate ion
chains spaced by 160 m along the cavity axis. Each chain can contain up to
20 individually addressable Yb\textsuperscript{+} ions coupled to the cavity
mode. We demonstrate deterministic distribution of ions between the sites of
the electrostatic periodic potential and control of the ion-cavity coupling.
The measured strength of this coupling should allow access to the strong
collective coupling regime with 10 ions. The optical cavity could
serve as a quantum information bus between ions or be used to generate a strong
wavelength-scale periodic optical potential.Comment: 15 pages, 6 figures, submitted to New Journal of Physic
Superconducting microfabricated ion traps
We fabricate superconducting ion traps with niobium and niobium nitride and
trap single 88Sr ions at cryogenic temperatures. The superconducting transition
is verified and characterized by measuring the resistance and critical current
using a 4-wire measurement on the trap structure, and observing change in the
rf reflection. The lowest observed heating rate is 2.1(3) quanta/sec at 800 kHz
at 6 K and shows no significant change across the superconducting transition,
suggesting that anomalous heating is primarily caused by noise sources on the
surface. This demonstration of superconducting ion traps opens up possibilities
for integrating trapped ions and molecular ions with superconducting devices.Comment: 3 pages, 2 figure
LRRU: Long-short Range Recurrent Updating Networks for Depth Completion
Existing deep learning-based depth completion methods generally employ
massive stacked layers to predict the dense depth map from sparse input data.
Although such approaches greatly advance this task, their accompanied huge
computational complexity hinders their practical applications. To accomplish
depth completion more efficiently, we propose a novel lightweight deep network
framework, the Long-short Range Recurrent Updating (LRRU) network. Without
learning complex feature representations, LRRU first roughly fills the sparse
input to obtain an initial dense depth map, and then iteratively updates it
through learned spatially-variant kernels. Our iterative update process is
content-adaptive and highly flexible, where the kernel weights are learned by
jointly considering the guidance RGB images and the depth map to be updated,
and large-to-small kernel scopes are dynamically adjusted to capture
long-to-short range dependencies. Our initial depth map has coarse but complete
scene depth information, which helps relieve the burden of directly regressing
the dense depth from sparse ones, while our proposed method can effectively
refine it to an accurate depth map with less learnable parameters and inference
time. Experimental results demonstrate that our proposed LRRU variants achieve
state-of-the-art performance across different parameter regimes. In particular,
the LRRU-Base model outperforms competing approaches on the NYUv2 dataset, and
ranks 1st on the KITTI depth completion benchmark at the time of submission.
Project page: https://npucvr.github.io/LRRU/.Comment: Published in ICCV 202
Individual addressing of ions using magnetic field gradients in a surface-electrode ion trap
Dense array of ions in microfabricated traps represent one possible way to
scale up ion trap quantum computing. The ability to address individual ions is
an important component of such a scheme. We demonstrate individual addressing
of trapped ions in a microfabricated surface-electrode trap using a magnetic
field gradient generated on-chip. A frequency splitting of 310(2) kHz for two
ions separated by 5 um is achieved. Selective single qubit operations are
performed on one of two trapped ions with an average of 2.2+/-1.0% crosstalk.
Coherence time as measured by the spin-echo technique is unaffected by the
field gradient.Comment: 3 pages, 3 figures; submitted to AP
Suppression of Heating Rates in Cryogenic Surface-Electrode Ion Traps
Dense arrays of trapped ions provide one way of scaling up ion trap quantum
information processing. However, miniaturization of ion traps is currently
limited by sharply increasing motional state decoherence at sub-100 um
ion-electrode distances. We characterize heating rates in cryogenically cooled
surface-electrode traps, with characteristic sizes in 75 um to 150 um range.
Upon cooling to 6 K, the measured rates are suppressed by 7 orders of
magnitude, two orders of magnitude below previously published data of similarly
sized traps operated at room temperature. The observed noise depends strongly
on fabrication process, which suggests further improvements are possible.Comment: 4 pages, 4 figure
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