6,697 research outputs found

    Pear-shaped lesion of the fossa of Rosenmüller

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    Retention cyst of the pharyngeal mucosal space is an accumulation of trapped mucous in the mucosa or adenoids of the pharynx. It is a benign lesion, often seen on routine imaging of the head and spine. It is typically a simple cyst originating from the pharyngeal mucosa, without invasion of the surrounding structures. It is important not to misinterpret a retention cyst as a malignant tumor. Patients are usually asymptomatic and do not need treatment

    Continuous-variable quantum non-demolishing interaction at a distance

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    A feasible setup of continuous-variable (CV) quantum non-demolishing (QND) interaction at a distance is proposed. If two distant experimentalists are able to locally perform identical QND interactions then the proposed realization requires only a single quantum channel and classical communication between them. A possible implementation of the proposed setup in recent quantum optical laboratories is discussed and an influence of Gaussian noise in the quantum channel on a quality of the implementation is analyzed. An efficient realization of the QND interaction at a distance can be a basic step to possible distributed quantum CV experiments between the distant laboratories.Comment: 5 pages, 2 figure

    Evolution of twin-beam in active optical media

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    We study the evolution of twin-beam propagating inside active media that may be used to establish a continuous variable entangled channel between two distant users. In particular, we analyze how entanglement is degraded during propagation, and determine a threshold value for the interaction time, above which the state become separable, and thus useless for entanglement based manipulations. We explicitly calculate the fidelity for coherent state teleportation and show that it is larger than one half for the whole range of parameters preserving entanglemenent.Comment: several misprints correcte

    Spin injection and spin accumulation in permalloy-copper mesoscopic spin valves

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    We study the electrical injection and detection of spin currents in a lateral spin valve device, using permalloy (Py) as ferromagnetic injecting and detecting electrodes and copper (Cu) as non-magnetic metal. Our multi-terminal geometry allows us to experimentally distinguish different magneto resistance signals, being 1) the spin valve effect, 2) the anomalous magneto resistance (AMR) effect and 3) Hall effects. We find that the AMR contribution of the Py contacts can be much bigger than the amplitude of the spin valve effect, making it impossible to observe the spin valve effect in a 'conventional' measurement geometry. However, these 'contact' magneto resistance signals can be used to monitor the magnetization reversal process, making it possible to determine the magnetic switching fields of the Py contacts of the spin valve device. In a 'non local' spin valve measurement we are able to completely isolate the spin valve signal and observe clear spin accumulation signals at T=4.2 K as well as at room temperature. We obtain spin diffusion lengths in copper of 1 micrometer and 350 nm at T=4.2 K and room temperature respectively.Comment: 8 pages (incl. figures), 7 figures, RevTex, conferenc
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