1,116 research outputs found

    Quantum Kerr tunneling vacua on a (DDˉ)4(D{\bar D})_4-brane: An emergent Kerr black hole in five dimensions

    Get PDF
    We revisit a non-perturbative space-time curvature theory, underlying a two form U(1) gauge dynamics, on a D4-brane. In particular, two different gauge choices for a two form are explored underlying the dynamics of a geometric torsion in a second order formalism. We obtain two non-extremal quantum Kerr geometries in five dimensions on a pair of (DDˉ)4(D{\bar D})_4-brane in a type IIA superstring theory. The quantum vacua are described by a vanishing torsion in a gauge choice, underlying a geometric realization, on a non-BPS brane. It is argued that the quantum Kerr vacua undergo tunneling and lead to a five dimensional Kerr black hole in Einstein vacuum. A low energy limit in the quantum Kerr vacua further re-assures an emergent Kerr black hole.Comment: 21 pages, 8 figure

    Emergent gravity/Non-linear U(1) gauge theory correspondence

    Full text link
    Kaluza-Klein gravity is revisted, with renewed interest, in a type IIB string theory on S1×K3S^1\times K3. The irreducible curvature tensors are worked out in the, T-dual, emergent gravity in 4D to yield a non-linear U(1) gauge theory. Interestingly, the T-duality may be seen to describe an open/closed string duality at a self-dual string coupling. The obtained deformation in AdS5AdS_5 black hole is analyzed to introduce the notion of temperature in the emergent gravity underlying the recent idea of entropic force.Comment: 6 page

    Quintessence and effective AdS brane geometries

    Full text link
    A geometric torsion dynamics leading to an effective curvature in a second order formalism on a D4-brane is revisited with a renewed interest. We obtain two effective AdS4AdS_4 brane geometries on a vacuum created pair of (DDˉ)3(D{\bar D})_3-brane. One of them is shown to describe an AdS Schwarzschild spinning black hole and the other is shown to describe a spinning black hole bound state. It is argued that a D-instanton in a vacuum created anti D3-brane within a pair may describe a quintessence. It may seen to incorporate a varying vacuum energy density in a brane universe. We consider the effective curvature scalar on S1×S1S^1\times S^1 to analyze torsion-less geometries on a vacuum created pair of (DDˉ)2(D{\bar D})_2-brane. The emergent AdS3AdS_3 brane is shown to describe a Schwarzschild and a Reissner-Nordstrom (RN) geometries in presence of extra dimension(s).Comment: 20 pages, expanded discussion and added referenc

    Emergent Schwarzschild and Reissner-Nordstrom black holes in 4D: An effective curvature sourced by a B2-field on a D4-brane

    Full text link
    We obtain a Schwarzschild and a Reissner-Nordstrom emergent black holes, by exploring the torsion dynamics in a generalized curvature formulation, underlying an effective D4-brane on S1. It is shown that a constant effective metric, sourced by a background fluctuation in B2-potential, on a D3-brane receives a dynamical quantum correction in presence of an electric charge.Comment: 7-pages, minor corrections, references added, to appear in Physical Review

    Quintessence and effective RN de Sitter brane geometries

    Full text link
    We revisit an effective space-time torsion curvature in a second order formalism, underlying the non-linear U(1)U(1) gauge dynamics, of a two form on a D4D_4-brane in type IIA superstring theory. The formalism incorporates the significance of a global NS two form into the theory via its perturbative coupling to a dynamical two form. In particular, we explore the non-linear gauge dynamics on a D4D_4-brane in presence of a non-trivial background metric. The fact that the global modes of a NS two form in an open string theory sources the background metric on a D4D_4-brane may hint at the existence of an anti D4D_4-brane in the formalism. An effective de Sitter universe is shown to emerge on a vacuum created pair of (DDˉ)3(D{\bar D})_3-brane by a local two form at the past horizon with a Big Bang. We obtain a number of 4D de Sitter quantum black holes, including a Reissner-Nordstrom vacuum, with and without a propagating torsion. The quantum black holes are shown to be free from curvature singularity at r0r\rightarrow 0. In a low energy limit, the nonperturbative correction sourced by a torison may seen to be insignificant. The quantum black hole undergoes an expansion in the limit and presumably identifies with the Einstein vacuum. Interestingly our analysis reveals a plausible quintessence (axion) on an anti D3D_3-brane which may source the dark energy in a D3D_3-brane universe. Arguably a brane universe moves away from its anti-brane due to the conjectured repulsive gravity underlying the quintessence. It leads to a growth in extra fifth dimension between a brane and an anti-brane which may provide a clue behind an accelerating universe observed in cosmology.Comment: 29 page

    Fascioliasis Control: In Vivo and In Vitro Phytotherapy of Vector Snail to Kill Fasciola Larva

    Get PDF
    Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva of Fasciola in infected snail Lymnaea acuminata were tested. Mortality of larvae were observed at 2 h, 4 h, 6 h, and 8 h, of treatment. In in vivo treatment, azadirachtin caused highest mortality in redia and cercaria larva (8 h, LC50 0.11, and 0.05 mg/L) whereas in in vitro condition allicin was highly toxic against redia and cercaria (8 h, LC50 0.01, and 0.009 mg/L). Toxicity of citral was lowest against redia and cercaria larva

    GARBHINI CHARDI (EMESIS GRAVIDARUM), ITS MANAGEMENT IN AYURVEDA

    Get PDF
    Acharya charaka has given specific importance to pregnant women and has compared them with oil filled vessel, which can be split by little displacement and to provide proper attention during pregnancy. Ayurvedic classics have mentioned Garbhini Chardi as one among the Vyakta garbha lakshanas, which can be correlated with emesis gravidarum. Emesis Gravidarum is a worldwide common obstetrical problem seen in the first trimester of pregnancy in about 50% of pregnant women.Nausea and vomiting tend to be worse in the morning termed Morning sickness, they frequently continue throughout the day. Vomiting in the early weeks of pregnancy is very common. If we do not correct the simple vomiting it leads to severe. So one should take care to treat this condition in initial stage and prevent complications. Different formulations and recipes have been mentioned in Ayurvedic classics which can easily be incorporated in day today life by a pregnant woman for Chardi. These are easy to prepare & easily available. Hence in this study an effort is made to list out simple & effective management of Garbhini Chardi with the help of various herbal preparations

    New Materials for Biosensor Construction

    Get PDF
    corecore