355 research outputs found
Large 2D Coulomb crystals in a radio frequency surface ion trap
We designed and operated a surface ion trap, with an ion-substrate distance
of 500\mum, realized with standard printed-circuit-board techniques. The trap
has been loaded with up to a few thousand Sr+ ions in the Coulomb-crystal
regime. An analytical model of the pseudo-potential allowed us to determine the
parameters that drive the trap into anisotropic regimes in which we obtain
large (N>150) purely 2D ion Coulomb crystals. These crystals may open a simple
and reliable way to experiments on quantum simulations of large 2D systems.Comment: 4 pages, 4 figure
Certified quantum non-demolition measurement of material systems
An extensive debate on quantum non-demolition (QND) measurement, reviewed in
Grangier et al. [Nature, {\bf 396}, 537 (1998)], finds that true QND
measurements must have both non-classical state-preparation capability and
non-classical information-damage tradeoff. Existing figures of merit for these
non-classicality criteria require direct measurement of the signal variable and
are thus difficult to apply to optically-probed material systems. Here we
describe a method to demonstrate both criteria without need for to direct
signal measurements. Using a covariance matrix formalism and a general noise
model, we compute meter observables for QND measurement triples, which suffice
to compute all QND figures of merit. The result will allow certified QND
measurement of atomic spin ensembles using existing techniques.Comment: 11 pages, zero figure
Electric Pulse Induced Resistive Switching, Electronic Phase Separation, and Possible Superconductivity in a Mott insulator
Metal-insulator transitions (MIT) belong to a class of fascinating physical
phenomena, which includes superconductivity, and colossal magnetoresistance
(CMR), that are associated with drastic modifications of electrical resistance.
In transition metal compounds, MIT are often related to the presence of strong
electronic correlations that drive the system into a Mott insulator state. In
these systems the MIT is usually tuned by electron doping or by applying an
external pressure. However, it was noted recently that a Mott insulator should
also be sensitive to other external perturbations such as an electric field. We
report here the first experimental evidence of a non-volatile
electric-pulse-induced insulator-to-metal transition and possible
superconductivity in the Mott insulator GaTa4Se8. Our Scanning Tunneling
Microscopy experiments show that this unconventional response of the system to
short electric pulses arises from a nanometer scale Electronic Phase Separation
(EPS) generated in the bulk material.Comment: Highlight in Advanced Functional Materials 18, 1-4 (2008) doi :
10.1002/adfm.20080055
Apple, condom, and cocaine - Body stuffing in prison: A case report
© 2018 The Author(s). Background: Drug dealers and drug users resort to body stuffing to hastily conceal illicit drugs by ingesting their drug packets. This practice represents a medical challenge because rupture of the often insecure packaging can be toxic and even lethal. In an emergency setting, official guidelines are needed to help the medical team decide on the proper treatment. A preliminary observation period is generally accepted but its duration varies from hours to eventual packet expulsion. Case presentation: This case involves a 20-year-old white man in detention who claimed to have ingested one cocaine packet wrapped in plastic food-wrap and a condom in anticipation of an impending cell search. He reached out to medical professionals on day 4 after having unsuccessfully tried several methods to expel the drug packet, including swallowing olive oil, natural laxatives, liters of water, and 12 carved apple chunks. An initial computed tomography scan confirmed multiple packet-sized images throughout his stomach and bowel. After 24 hours of observation and normal bowel movements without expelling any packets, a subsequent scan found only one air-lined packet afloat in the gastric content. Due to the prolonged retention of the package there was an increased risk of rupture. The packet was eventually removed by laparoscopic gastrotomy. Conclusions: This case report illustrates that observation time needs to be adapted to each individual case of body stuffing. Proof of complete drug package evacuation ensures secure patient discharge. Body stuffers should be routinely asked for a detailed history, including how the drug is wrapped, and whether or not they ingested other substances to help expel the packets. The history enables the accurate interpretation of imaging. Repeated imaging can help follow the progress of packets if not all have been expelled during the observation period. Drug packets should be surgically removed in case of prolonged retention. To ensure the best possible outcomes, patients should have access to high-quality, private, and confidential medical care, which is equal to that offered to the general population. This is paramount to earning trust and collaboration from people in detention who resort to body stuffing
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