7,406 research outputs found
Selective writing and read-out of a register of static qubits
We propose a setup comprising an arbitrarily large array of static qubits
(SQs), which interact with a flying qubit (FQ). The SQs work as a quantum
register, which can be written or read-out by means of the FQ through quantum
state transfer (QST). The entire system, including the FQ's motional degrees of
freedom, behaves quantum mechanically. We demonstrate a strategy allowing for
selective QST between the FQ and a single SQ chosen from the register. This is
achieved through a perfect mirror located beyond the SQs and suitable
modulation of the inter-SQ distances.Comment: 14 pages, 4 figure
High-energy antiprotons from old supernova remnants
A recently proposed model (arXiv:0903.2794) explains the rise in energy of
the positron fraction measured by the PAMELA satellite in terms of hadronic
production of positrons in aged supernova remnants, and acceleration therein.
Here we present a preliminary calculation of the anti-proton flux produced by
the same mechanism. While the model is consistent with present data, a rise of
the antiproton to proton ratio is predicted at high energy, which strikingly
distinguishes this scenario from other astrophysical explanations of the
positron fraction (like pulsars). We briefly discuss important implications for
Dark Matter searches via antimatter.Comment: 4 pages, 1 figure; minor revision, matches published versio
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Hypertensive phase and early complications after Ahmed glaucoma valve implantation with intraoperative subtenon triamcinolone acetonide
Objective: To evaluate intraoperative subtenon triamcinolone acetonide (TA) as an adjunct to Ahmed glaucoma valve (AGV) implantation. Design: Retrospective comparative case series. Participants: Forty-two consecutive cases of uncontrolled glaucoma undergoing AGV implantation: 19 eyes receiving intraoperative subtenon TA and 23 eyes that did not receive TA. Methods: A retrospective chart review was performed on consecutive pseudophakic adult patients with uncontrolled glaucoma undergoing AGV with and without intraoperative subtenon TA injection by a single surgeon. Clinical data were collected from 42 eyes and analyzed for the first 6 months after surgery. Main outcome measures Primary outcomes included intraocular pressure (IOP) and number of glaucoma medications prior to and after AGV implantation. The hypertensive phase (HP) was defined as an IOP measurement of greater than 21 mmHg (with or without medications) during the 6-month postoperative period that was not a result of tube obstruction, retraction, or malfunction. Postoperative complications and visual acuity were analyzed as secondary outcome measures. Results: Five out of 19 (26%) TA cases and 12 out of 23 (52%) non-TA cases developed the HP (P=0.027). Mean IOP (14.2±4.6 in TA cases versus [vs] 14.7±5.0 mmHg in non-TA cases; P=0.78), and number of glaucoma medications needed (1.8±1.3 in TA cases vs 1.6±1.1 in the comparison group; P=0.65) were similar between both groups at 6 months. Although rates of serious complications did not differ between the groups (13% in the TA group vs 16% in the non-TA group), early tube erosion (n=1) and bacterial endophthalmitis (n=1) were noted with TA but not in the non-TA group. Conclusions: Subtenon TA injection during AGV implantation may decrease the occurrence of the HP but does not alter the ultimate IOP outcome and may pose increased risk of serious complications within the first 6 months of surgery
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