8,677 research outputs found

    Coexistence of the antiferromagnetic and superconducting order and its effect on spin dynamics in electron-doped high-TcT_{c} cuprates

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    In the framework of the slave-boson approach to the tttJt-t'-t''-J model, it is found that for electron-doped high-TcT_c cuprates, the staggered antiferromagnetic (AF) order coexists with superconducting (SC) order in a wide doping level ranged from underdoped to nearly optimal doping at the mean-field level. In the coexisting phase, it is revealed that the spin response is commensurate in a substantial frequency range below a crossover frequency ωc\omega_{c} for all dopings considered, and it switches to the incommensurate structure when the frequency is higher than ωc\omega_{c}. This result is in agreement with the experimental measurements. Comparison of the spin response between the coexisting phase and the pure SC phase with a dx2y2d_{x^{2}-y^{2}}-wave pairing plus a higher harmonics term (DP+HH) suggests that the inclusion of the two-band effect is important to consistently account for both the dispersion of the spin response and the non-monotonic gap behavior in the electron-doped cuprates.Comment: 6 pages, 5 figure

    Spontaneous Relaxation of a Charge Qubit under Electrical Measurement

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    In this work we first derive a generalized conditional master equation for quantum measurement by a mesoscopic detector, then study the readout characteristics of qubit measurement where a number of new features are found. The work would in particular highlight the qubit spontaneous relaxation effect induced by the measurement itself rather than an external thermal bath.Comment: 4 pages, 2 figures; an error in Eq.(8) is correcte

    Torsion cosmological dynamics

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    In this paper, the dynamical attractor and heteroclinic orbit have been employed to make the late-time behaviors of the model insensitive to the initial condition and thus alleviate the fine-tuning problem in the torsion cosmology. The late-time de Sitter attractor indicates that torsion cosmology is an elegant scheme and the scalar torsion mode is an interesting geometric quantity for physics. The numerical solutions obtained by Nester et al. are not periodic solutions, but are quasi-periodic solutions near the focus for the coupled nonlinear equations.Comment: 4 pages, 3 figure

    Computational fluid dynamic analysis of bioprinted self-supporting perfused tissue models

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    Natural tissues are incorporated with vasculature, which is further integrated with a cardiovascular system responsible for driving perfusion of nutrient‐rich oxygenated blood through the vasculature to support cell metabolism within most cell‐dense tissues. Since scaffold‐free biofabricated tissues being developed into clinical implants, research models, and pharmaceutical testing platforms should similarly exhibit perfused tissue‐like structures, we generated a generalizable biofabrication method resulting in self‐supporting perfused (SSuPer) tissue constructs incorporated with perfusible microchannels and integrated with the modular FABRICA perfusion bioreactor. As proof of concept, we perfused an MLO‐A5 osteoblast‐based SSuPer tissue in the FABRICA. Although our resulting SSuPer tissue replicated vascularization and perfusion observed in situ, supported its own weight, and stained positively for mineral using Von Kossa staining, our in vitro results indicated that computational fluid dynamics (CFD) should be used to drive future construct design and flow application before further tissue biofabrication and perfusion. We built a CFD model of the SSuPer tissue integrated in the FABRICA and analyzed flow characteristics (net force, pressure distribution, shear stress, and oxygen distribution) through five SSuPer tissue microchannel patterns in two flow directions and at increasing flow rates. Important flow parameters include flow direction, fully developed flow, and tissue microchannel diameters matched and aligned with bioreactor flow channels. We observed that the SSuPer tissue platform is capable of providing direct perfusion to tissue constructs and proper culture conditions (oxygenation, with controllable shear and flow rates), indicating that our approach can be used to biofabricate tissue representing primary tissues and that we can model the system in silico

    A simple derivation of level spacing of quasinormal frequencies for a black hole with a deficit solid angle and quintessence-like matter

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    In this paper, we investigate analytically the level space of the imaginary part of quasinormal frequencies for a black hole with a deficit solid angle and quintessence-like matter by the Padmanabhan's method \cite{Padmanabhan}. Padmanabhan presented a method to study analytically the imaginary part of quasinormal frequencies for a class of spherically symmetric spacetimes including Schwarzschild-de Sitter black holes which has an evenly spaced structure. The results show that the level space of scalar and gravitational quasinormal frequencies for this kind of black holes only depend on the surface gravity of black-hole horizon in the range of -1 < w < -1/3, respectively . We also extend the range of ww to w1w \leq -1, the results of which are similar to that in -1 < w < -1/3 case. Particularly, a black hole with a deficit solid angle in accelerating universe will be a Schwarzschild-de Sitter black hole, fixing w=1w = -1 and ϵ2=0\epsilon^2 = 0. And a black hole with a deficit solid angle in the accelerating universe will be a Schwarzschild black hole,when ρ0=0\rho_0 = 0 and ϵ2=0\epsilon^2 = 0. In this paper, ww is the parameter of state equation, ϵ2\epsilon^2 is a parameter relating to a deficit solid angle and ρ0\rho_0 is the density of static spherically symmetrical quintessence-like matter at r=1r = 1.Comment: 6 pages, Accepted for publication in Astrophysics & Space Scienc

    A novel quantum key distribution scheme with orthogonal product states

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    The general conditions for the orthogonal product states of the multi-state systems to be used in quantum key distribution (QKD) are proposed, and a novel QKD scheme with orthogonal product states in the 3x3 Hilbert space is presented. We show that this protocol has many distinct features such as great capacity, high efficiency. The generalization to nxn systems is also discussed and a fancy limitation for the eavesdropper's success probability is reached.Comment: 4 Pages, 3 Figure

    catena-Poly[[bis­[4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenol]cadmium(II)]-μ-fumarato]

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    In the polymeric title compound, [Cd(C4H2O4)(C19H12N4O)2]n, the CdII centre is eight-coordinated within an N4O4 donor set derived from two chelating 4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenol ligands and two asymmetrically chelating carboxyl­ate residues of bridging fumarate dianions. The linear chains are linked into a layer in the ac plane via O—H⋯Ocarboxyl­ate hydrogen bonds. Layers are connected into double layers via N—H⋯Ocarboxyl­ate hydrogen bonds and these stack along the b axis. C—H⋯π inter­actions are also present. Disorder in the ethyl­ene portion of the fumarate was modelled over two positions, the major component having a site-occupancy factor of 0.677 (15)
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