1,539 research outputs found

    Teleportation on a quantum dot array

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    We present a model of quantum teleportation protocol based on a double quantum dot array. The unknown qubit is encoded using a pair of quantum dots, coupled by tunneling, with one excess electron. It is shown how to create maximally entangled states with this kind of qubits using an adiabatically increasing Coulomb repulsion between different pairs. This entangled states are exploited to perform teleportation again using an adiabatic coupling between them and the incoming unknown state. Finally, a sudden separation of Bob's qubit enables a time evolution of Alice's state providing a modified version of standard Bell measurement. Substituting the four quantum dots entangled state with a chain of coupled DQD's, a quantum channel with high fidelity arises from this scheme allowing the transmission over long distances.Comment: 4 pages, 2 figure

    Entanglement properties of spin models in triangular lattices

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    The different quantum phases appearing in strongly correlated systems as well as their transitions are closely related to the entanglement shared between their constituents. In 1D systems, it is well established that the entanglement spectrum is linked to the symmetries that protect the different quantum phases. This relation extends even further at the phase transitions where a direct link associates the entanglement spectrum to the conformal field theory describing the former. For 2D systems much less is known. The lattice geometry becomes a crucial aspect to consider when studying entanglement and phase transitions. Here, we analyze the entanglement properties of triangular spin lattice models by considering also concepts borrowed from quantum information theory such as geometric entanglement.Comment: 19 pages, 8 figure

    Muscle metastases from gallbladder cancer

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    Gallbladder cancer is a highly fatal disease with poor prognosis; indeed, a high proportion of tumours are diagnosed at an advanced stage. Metastases are commonly detected in regional lymph nodes, liver and peritoneum, but unusual sites of spread such as thyroid and breast have also been described in the literature.We report a case of unsuspected muscle metastases, associated to pulmonary metastases, detected by FDG-PET/CT in a patient with previously removed gallbladder cancer and persistent episodes of haemoptysis

    A case study of spin-11 Heisenberg model in a triangular lattice

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    We study the spin-11 model in a triangular lattice in presence of a uniaxial anisotropy field using a Cluster Mean-Field approach (CMF). The interplay between antiferromagnetic exchange, lattice geometry and anisotropy forces Gutzwiller mean-field approaches to fail in a certain region of the phase diagram. There, the CMF yields two supersolid (SS) phases compatible with those present in the spin-1/21/2 XXZ model onto which the spin-11 system maps. Between these two SS phases, the three-sublattice order is broken and the results of the CMF depend heavily on the geometry and size of the cluster. We discuss the possible presence of a spin liquid in this region.Comment: 7 pages, 4 figures, RevTeX 4. The abstract and conclusions have been modified and the manuscript has been extende

    A Resource-based Rule Engine for energy savings recommendations in Educational Buildings

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    Raising awareness among young people on the relevance of behaviour change for achieving energy savings is widely considered as a key approach towards long-term and cost-effective energy efficiency policies. The GAIA Project aims to deliver a comprehensive solution for both increasing awareness on energy efficiency and achieving energy savings in school buildings. In this framework, we present a novel rule engine that, leveraging a resource-based graph model encoding relevant application domain knowledge, accesses IoT data for producing energy savings recommendations. The engine supports configurability, extensibility and ease-of-use requirements, to be easily applied and customized to different buildings. The paper introduces the main design and implementation details and presents a set of preliminary performance results

    Charge transfer and coherence dynamics of tunnelling system coupled to a harmonic oscillator

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    We study the transition probability and coherence of a two-site system, interacting with an oscillator. Both properties depend on the initial preparation. The oscillator is prepared in a thermal state and, even though it cannot be considered as an extended bath, it produces decoherence because of the large number of states involved in the dynamics. In the case in which the oscillator is intially displaced a coherent dynamics of change entangled with oscillator modes takes place. Coherency is however degraded as far as the oscillator mass increases producing a increasingly large recoherence time. Calculations are carried on by exact diagonalization and compared with two semiclassical approximations. The role of the quantum effects are highlighted in the long-time dynamics, where semiclassical approaches give rise to a dissipative behaviour. Moreover, we find that the oscillator dynamics has to be taken into account, even in a semiclassical approximation, in order to reproduce a thermally activated enhancement of the transition probability

    A parathyroid carcinoma within a cold thyroid nodule

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    We report the case of a 71-year-old woman who was referred to our institute with a solid nodule in the right thyroid lobe and hypercalcemia. Ultrasound revealed a well-vascularized right thyroid nodule that was identified as a cold area by 99mTc-sodium pertechnetate scan. Fine-needle aspiration showed a follicular lesion and blood tests revealed hypercalcemia and hyperparathyroidism. A 99mTc-methoxyisobutylisonitrile (99mTc-Sestamibi) scan was subsequently performed revealing a focal area of increased uptake in the right thyroid lobe, within the cold area detected by the thyroid scan. A right emithyroidectomy and right superior and inferior parathyroidectomy was performed and histopathological examination showed a parathyroid carcinoma (immunohistochemistry positive for PTH and chromogranin A, Ki-67 10%) associated with follicular hyperplasia

    Routing quantum information in spin chains

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    Two different models for performing efficiently routing of a quantum state are presented. Both cases involve an XX spin chain working as data bus and additional spins that play the role of sender and receivers, one of which is selected to be the target of the quantum state transmission protocol via a coherent quantum coupling mechanism making use of local/global magnetic fields. Quantum routing is achieved, in the first of the models considered, by weakly coupling the sender and the receiver to the data bus. In the second model, strong magnetic fields acting on additional spins located between the sender/receiver and the data bus allow us to perform high fidelity routing.Comment: added references in v

    [18F] FDG uptake: pay attention to candies

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    [18F]Fluorodeoxyglucose ([18F]FDG) is a positron emission radiotracer whose biodistribution is similar to glucose. The similar biodistribution of [18F]FDG and glucose in the human body requires a fasting condition for at least six hours prior to performing a [18F]FDG positron emission tomography ([18F]FDG PET) study
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