4,300 research outputs found

    State Carving in a Chirally-Coupled Atom-Nanophotonic Cavity

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    Coherent quantum control of multiqubit systems represents one of the challenging tasks in quantum science and quantum technology. Here we theoretically investigate the reflectivity spectrum in an atom-nanophotonic cavity with collective nonreciprocal couplings. In the strong-coupling regime with a high cooperativity, we theoretically predict distinct on-resonance spectral dips owing to destructive interferences of chiral couplings. Due to the well-separated multiple dips in the spectrum, a contrasted reflectivity suggests a new control knob over the desired entangled state preparation. We propose to utilize such atom-nanophotonic cavity to quantum engineer the atomic internal states via photon-mediated dipole-dipole interactions and the chirality of decay channels, where the atomic Bell state and W states for arbitrary number of atoms can be tailored and heralded by state carving in the single-photon reflection spectrum. Our results pave the way toward quantum engineering of multiqubit states and offer new opportunities for coherent and scalable multipartite entanglement transport in atoms coupled to nanophotonic devices.Comment: 5 figure

    Generating scalable graph states in an atom-nanophotonic interface

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    Scalable graph states are essential for measurement-based quantum computation and many entanglement-assisted applications in quantum technologies. Generation of these multipartite entangled states requires a controllable and efficient quantum device with delicate design of generation protocol. Here we propose to prepare high-fidelity and scalable graph states in one and two dimensions, which can be tailored in an atom-nanophotonic cavity via state carving technique. We propose a systematic protocol to carve out unwanted state components, which facilitates scalable graph states generations via adiabatic transport of a definite number of atoms in optical tweezers. An analysis of state fidelity is also presented, and the state preparation probability can be optimized via multiqubit state carvings and sequential single-photon probes. Our results showcase the capability of an atom-nanophotonic interface for creating graph states and pave the way toward novel problem-specific applications using scalable high-dimensional graph states with stationary qubits.Comment: 5 figures with supplemental materia

    Rational Approximate Symmetries of KdV Equation

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    We construct one-parameter deformation of the Dorfman Hamiltonian operator for the Riemann hierarchy using the quasi-Miura transformation from topological field theory. In this way, one can get the approximately rational symmetries of KdV equation and then investigate its bi-Hamiltonian structure.Comment: 14 pages, no figure

    Gravity Waves from Quantum Stress Tensor Fluctuations in Inflation

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    We consider the effects of the quantum stress tensor fluctuations of a conformal field in generating gravity waves in inflationary models. We find a non-scale invariant, non-Gaussian contribution which depends upon the total expansion factor between an initial time and the end of inflation. This spectrum of gravity wave perturbations is an illustration of a negative power spectrum, which is possible in quantum field theory. We discuss possible choices for the initial conditions. If the initial time is taken to be sufficiently early, the fluctuating gravity waves are potentially observable both in the CMB radiation and in gravity wave detectors, and could offer a probe of transplanckian physics. The fact that they have not yet been observed might be used to constrain the duration and energy scale of inflation.Comment: 17 -pages, no figure

    PHOTOCHEMICAL RING-OPENING IN meso-CHLORINATED CHLOROPHYLLS

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    Irradiation of 20-chloro-chlorophylls of the a-type with visible light produces long-wavelength shifted photoproducts, which transform in the dark to linear tetrapyrroles (bile pigments). The possible significance for chlorophyll degradation is discussed

    A BGG-type resolution for tensor modules over general linear superalgebra

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    We construct a Bernstein-Gelfand-Gelfand type resolution in terms of direct sums of Kac modules for the finite-dimensional irreducible tensor representations of the general linear superalgebra. As a consequence it follows that the unique maximal submodule of a corresponding reducible Kac module is generated by its proper singular vector.Comment: 11pages, LaTeX forma

    Presentation and Outcomes After Medical and Surgical Treatment Versus Medical Treatment Alone of Spontaneous Infectious Spondylodiscitis: A Systematic Literature Review and Meta-Analysis.

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    Study Design: Systematic literature review. Objectives: The aims of this study were to (1) describe the clinical features, disabilities, and incidence of neurologic deficits of pyogenic spondylodiscitis prior to treatment and (2) compare the functional outcomes between patients who underwent medical treatment alone or in combination with surgery for pyogenic spondylodiscitis. Methods: A systematic literature review was performed using PubMed according to PRISMA guidelines. No year restriction was put in place. Statistical analysis of pooled data, when documented in the original report (ie, number of patients with desired variable and number of patients evaluated), was conducted to determine the most common presenting symptoms, incidence of pre- and postoperative neurologic deficits, associated comorbidities, infectious pathogens, approach for surgery when performed, and duration of hospitalization. Outcomes data, including return to work status, resolution of back pain, and functional recovery were also pooled among all studies and surgery-specific studies alone. Meta-analysis of studies with subgroup analysis of pain-free outcome in surgical and medical patients was performed. Results: Fifty of 1286 studies were included, comprising 4173 patients undergoing either medical treatment alone or in combination with surgery. Back pain was the most common presenting symptom, reported in 91% of patients. Neurologic deficit was noted in 31% of patients. Conclusion: Medical management remains first-line treatment of infectious pyogenic spondylodiscitis. Surgery may be indicated for progressive pain, persistent infection on imaging, deformity or neurologic deficits. If surgery is required, reported literature shows potential for significant pain reduction, improved neurologic function and a high number of patients returning to a normal functional/work status
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