6,155 research outputs found

    New Bardeen-Cooper-Schrieffer-type theory at finite temperature with particle-number conservation

    Full text link
    We formulate a new Bardeen-Cooper-Schrieffer (BCS)-type theory at finite temperature, by deriving a set of variational equations of the free energy after the particle-number projection. With its broad applicability, this theory can be a useful tool for investigating the pairing phase transition in finite systems with the particle-number conservation. This theory provides effects of the symmetry-restoring fluctuation (SRF) for the pairing phenomena in finite fermionic systems, distinctively from those of additional quantum fluctuations. It is shown by numerical calculations that the phase transition is compatible with the conservation in this theory, and that the SRF shifts up the critical temperature (TcrT^\mathrm{cr}). This shift of TcrT^\mathrm{cr} occurs due to reduction of degrees-of-freedom in canonical ensembles, and decreases only slowly as the particle-number increases (or as the level spacing narrows), in contrast to the conventional BCS theory.Comment: 10 pages including 3 figures, to be published in Phys. Rev.

    Eternally accelerating spacelike braneworld cosmologies

    Get PDF
    We construct an eternally inflating spacelike brane world model. If the space dimension of the brane is three (SM2) or six (SM5) for M theory or four (SD3) for superstring theory, a time-dependent nn-form field would supply a constant energy density and cause exponentially expansion of the spacelike brane. In these cases, the hyperbolic space perpendicular to the brane would not vary in size. In the other cases, however, the extra space would vary in size.Comment: 8 pages, Mod. Phys. Lett. A Vol.21, No.40(2006) 2989-299

    Asymptotic flatness at null infinity in arbitrary dimensions

    Full text link
    We define the asymptotic flatness and discuss asymptotic symmetry at null infinity in arbitrary dimensions using the Bondi coordinates. To define the asymptotic flatness, we solve the Einstein equations and look at the asymptotic behavior of gravitational fields. Then we show the asymptotic symmetry and the Bondi mass loss law with the well-defined definition.Comment: 12 pages, published version in PR

    On the Navier-Stokes equations with rotating effect and prescribed outflow velocity

    Full text link
    We consider the equations of Navier-Stokes modeling viscous fluid flow past a moving or rotating obstacle in Rd\mathbb{R}^d subject to a prescribed velocity condition at infinity. In contrast to previously known results, where the prescribed velocity vector is assumed to be parallel to the axis of rotation, in this paper we are interested in a general outflow velocity. In order to use LpL^p-techniques we introduce a new coordinate system, in which we obtain a non-autonomous partial differential equation with an unbounded drift term. We prove that the linearized problem in Rd\mathbb{R}^d is solved by an evolution system on Lσp(Rd)L^p_{\sigma}(\mathbb{R}^d) for 1<p<1<p<\infty. For this we use results about time-dependent Ornstein-Uhlenbeck operators. Finally, we prove, for pdp\geq d and initial data u0Lσp(Rd)u_0\in L^p_{\sigma}(\mathbb{R}^d), the existence of a unique mild solution to the full Navier-Stokes system.Comment: 18 pages, to appear in J. Math. Fluid Mech. (published online first

    Ordering Process and Its Hole Concentration Dependence of the Stripe Order in La{2-x}Sr{x}NiO{4}

    Full text link
    Ordering process of stripe order in La{2-x}Sr{x}NiO{4} with x being around 1/3 was investigated by neutron diffraction experiments. When the stripe order is formed at high temperature, incommensurability \epsilon of the stripe order has a tendency to show the value close to 1/3 for the samples with x at both sides of 1/3. With decreasing temperature, however, \epsilon becomes close to the value determined by the linear relation of \epsilon = n_h, where n_h is a hole concentration. This variation of the \epsilon strongly affects the character of the stripe order through the change of the carrier densities in stripes and antiferromagnetic domains.Comment: 5 pages, 3 figures, REVTeX, to be published in Phys. Rev.

    Angular momentum at null infinity in higher dimensions

    Full text link
    We define the angular momentum at null infinity in higher dimensions. The asymptotic symmetry at null infinity becomes the Poincare group in higher dimensions. This fact implies that the angular momentum can be defined without any ambiguities such as supertranslation in four dimensions. Indeed we can show that the angular momentum in our definition is transformed covariantly with respect to the Poincare group.Comment: 13 page

    The cDNA and deduced amino acid sequence of the γ subunit of the L-type calcium channel from rabbit skeletal muscle

    Get PDF
    Complementary DNAs for the γ subunit of the calcium channel of rabbit skeletal muscle were isolated on the basis of peptide sequences derived from the purified protein. The deduced primary structure is without homology to other known protein sequences and is consistent with the γ subunit being an integral membrane protein

    Adsorption of heavy metals in mine wastewater by Mongolian natural zeolite

    Get PDF
    AbstractIn the first, Mongolian natural zeolites, whose base components were clinoptilolite, mordenite, and chabazite, were characterized in terms of element content, cation exchange capacity, and the like. Since the molar ratios of aluminum relative to silicon contained in Mongolian natural zeolites used in this study were lower than those of pure zeolites, the natural zeolite samples contained substantial amounts of impurities. The cation exchange capacity of the natural zeolite sample relatively increased with increasing aluminum content in the zeolite sample. Secondly, the batch equilibrium adsorptions of heavy metals, i.e., copper, zinc, and manganese, from model aqueous wastewater by Mongolian natural zeolites were carried. The natural zeolites could adsorb and remove the heavy metals in the aqueous solutions. The precipitation of metal hydroxide affected the results of adsorption in some cases. The saturated adsorbed amounts of the heavy metals estimated by Langmuir equation were almost same with one another, increased with solution pH and with cation exchange capacity of the natural zeolite

    Exponentially growing solutions in homogeneous Rayleigh-Benard convection

    Get PDF
    It is shown that homogeneous Rayleigh-Benard flow, i.e., Rayleigh-Benard turbulence with periodic boundary conditions in all directions and a volume forcing of the temperature field by a mean gradient, has a family of exact, exponentially growing, separable solutions of the full non-linear system of equations. These solutions are clearly manifest in numerical simulations above a computable critical value of the Rayleigh number. In our numerical simulations they are subject to secondary numerical noise and resolution dependent instabilities that limit their growth to produce statistically steady turbulent transport.Comment: 4 pages, 3 figures, to be published in Phys. Rev. E - rapid communication
    corecore