34 research outputs found

    Probing quantum phases of ultracold atoms in optical lattices by transmission spectra in cavity QED

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    Studies of ultracold atoms in optical lattices link various disciplines, providing a playground where fundamental quantum many-body concepts, formulated in condensed-matter physics, can be tested in much better controllable atomic systems, e.g., strongly correlated phases, quantum information processing. Standard methods to measure quantum properties of Bose-Einstein condensates (BECs) are based on matter-wave interference between atoms released from traps which destroys the system. Here we propose a nondestructive method based on optical measurements, and prove that atomic statistics can be mapped on transmission spectra of a high-Q cavity. This can be extremely useful for studying phase transitions between Mott insulator and superfluid states, since various phases show qualitatively distinct light scattering. Joining the paradigms of cavity quantum electrodynamics (QED) and ultracold gases will enable conceptually new investigations of both light and matter at ultimate quantum levels, which only recently became experimentally possible. Here we predict effects accessible in such novel setups.Comment: 6 pages, 3 figure

    A Rydberg Quantum Simulator

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    Following Feynman and as elaborated on by Lloyd, a universal quantum simulator (QS) is a controlled quantum device which reproduces the dynamics of any other many particle quantum system with short range interactions. This dynamics can refer to both coherent Hamiltonian and dissipative open system evolution. We investigate how laser excited Rydberg atoms in large spacing optical or magnetic lattices can provide an efficient implementation of a universal QS for spin models involving (high order) n-body interactions. This includes the simulation of Hamiltonians of exotic spin models involving n-particle constraints such as the Kitaev toric code, color code, and lattice gauge theories with spin liquid phases. In addition, it provides the ingredients for dissipative preparation of entangled states based on engineering n-particle reservoir couplings. The key basic building blocks of our architecture are efficient and high-fidelity n-qubit entangling gates via auxiliary Rydberg atoms, including a possible dissipative time step via optical pumping. This allows to mimic the time evolution of the system by a sequence of fast, parallel and high-fidelity n-particle coherent and dissipative Rydberg gates.Comment: 8 pages, 4 figure

    Guidelines for Accurate and Transparent Health Estimates Reporting: the GATHER statement

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    Measurements of health indicators are rarely available for every population and period of interest, and available data may not be comparable. The Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) define best reporting practices for studies that calculate health estimates for multiple populations (in time or space) using multiple information sources. Health estimates that fall within the scope of GATHER include all quantitative population-level estimates (including global, regional, national, or subnational estimates) of health indicators, including indicators of health status, incidence and prevalence of diseases, injuries, and disability and functioning; and indicators of health determinants, including health behaviours and health exposures. GATHER comprises a checklist of 18 items that are essential for best reporting practice. A more detailed explanation and elaboration document, describing the interpretation and rationale of each reporting item along with examples of good reporting, is available on the GATHER website

    In vivo Analysis of Choroid Plexus Morphogenesis in Zebrafish

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    BACKGROUND: The choroid plexus (ChP), a component of the blood-brain barrier (BBB), produces the cerebrospinal fluid (CSF) and as a result plays a role in (i) protecting and nurturing the brain as well as (ii) in coordinating neuronal migration during neurodevelopment. Until now ChP development was not analyzed in living vertebrates due to technical problems. METHODOLOGY/PRINCIPAL FINDINGS: We have analyzed the formation of the fourth ventricle ChP of zebrafish in the GFP-tagged enhancer trap transgenic line SqET33-E20 (Gateways) by a combination of in vivo imaging, histology and mutant analysis. This process includes the formation of the tela choroidea (TC), the recruitment of cells from rhombic lips and, finally, the coalescence of TC resulting in formation of ChP. In Notch-deficient mib mutants the first phase of this process is affected with premature GFP expression, deficient cell recruitment into TC and abnormal patterning of ChP. In Hedgehog-deficient smu mutants the second phase of the ChP morphogenesis lacks cell recruitment and TC cells undergo apoptosis. CONCLUSIONS/SIGNIFICANCE: This study is the first to demonstrate the formation of ChP in vivo revealing a role of Notch and Hedgehog signalling pathways during different developmental phases of this process
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