By presenting the mass-independent potentials of the Kaluza-Klein (KK) modes in the corresponding Schrödinger equations, we investigate the localization and mass spectra of various bulk matter fields on an AdS thick brane. For a spin 0 scalar $Φ$ coupled with itself and the domain-wall-forming field $ϕ$ via a coupling potential
$V=(λϕ^{2}-u^{2})Φ^{2}+τΦ^{4}$, the localization and spectrum are decided by a critical coupling constant $λ_{0}$. When $λ>λ_0$, the potential of the scalar KK modes in the corresponding Schrödinger equation tends to infinite when far away from the brane, which results in that there exist infinite discrete scalar bound KK states, and the massless modes could be trapped on the AdS brane by fine-tuning of parameters. When $λ<λ_0$, the potential of the scalar KK modes tends to negative infinite when far away from the brane, hence there does not exist any scalar bound KK state. For a spin 1 vector, the situation is same like the scalar with a coupling constant $λ>λ_0$, but the zero mode can not be localized on the brane. For a spin 1/2 fermion, we introduce the usual Yukawa coupling $η\barΨϕΨ$, and find that the localization of the fermion is decided by a critical coupling constant $η_0$. For $η> η_0$, the four-dimensional massless left chiral fermion and massive Dirac fermions consisted of the pairs of coupled left-hand and right-hand KK modes could be localized on the AdS brane, and the massive Dirac fermions have a set of discrete mass spectrum. While for the case $0<η< η_{0}$, no four-dimensional Dirac fermion can be localized on the AdS brane.
Quantum cosmology, inflationary brane-world creation and dS/CFT correspondence
在经典和量子水平上讨论了粘在两个d5 de Sitter体上的4d de Sitter（暴胀）边界的产生（考虑了膜QFT通过相应的迹反常诱导的有效作用）.量子效应使经典的de Sitter膜半径减小或产生新的半径更小的de Sitter膜。重要的是，膜CFT可以被选择为与5d de Sitter体之一对偶，使得de Sitter膜世界与dS/CFT对应的显式关系。这样，引力在膜上的局部化就被显示出来了。移动（含时）deSitter膜在d5 SdS BH被认为是。在特殊的坐标系中，膜方程类似于量子修正的FRW方程，并与SAdS BH体中的类似膜方程进行了比较。
Hidden sector D7-branes with non-zero gauge flux are a generic feature of type IIB compactifications. A non-vanishing Fayet-Iliopoulos term induced by non-zero gauge flux leads to a T-brane configuration. Expanding the D7-brane action around this T-brane background in the presence of three-form supersymmetry breaking fluxes, we obtain a positive definite contribution to the moduli scalar potential which can be used as an uplifting source for de Sitter vacua. In this way we provide a higher-dimensional understanding of known 4D mechanisms of de Sitter uplifting based on hidden sector F-terms wh…
We consider explicit type II string constructions of backgrounds containing warped and squashed anti de Sitter spaces. These are obtained via T duality from brane intersections including dyonic black strings, plane waves and monopoles. We also study the supersymmetry of these solutions and discuss special values of the deformation parameters.
Thermodynamic properties of Schwarzschild-Anti de-Sitter (Sch-AdS) and Reissner-Nordström-Anti de-Sitter (RN-AdS) blackholes in 3+1 dimensional spacetime are studied critically with special reference to the warped braneworld black holes with non-vanishing cosmological constant on the brane. Explicit dependence of the thermodynamic variables on the parameters of the braneworld model such as the induced three brane cosmological constant as well as the bulk cosmological constant have been determined. Hawking-Page phase transition has been discussed for both Sch-AdS and RN-AdS black holes. At the …
Can We Live on the Brane in Schwarzschild-anti de Sitter Black Hole?
本文研究了以Schwarzschild-anti de Sitter黑洞（S-AdS BH）为精确解的d5高阶导数引力模型。在完备作用量中加入表面反项，当膜趋于无穷大时，表面反项由体AdS时空的有限性条件确定。因此，膜（可观测宇宙）是根据d5理论参数动态定义的（膜张力是固定的）。膜半径总是大于视界半径，4D宇宙本身可能是静态的或暴胀的。这个模型的自然一般化给出了AdS/CFT对应的次领先顺序的翘曲紧化（动态生成膜）。
Holographic Thermodynamic on the Brane in Topological Reissner-Nordström de Sitter Space
我们考虑拓扑Reissner-Nordström de Sitter黑洞的体背景中的膜宇宙。当膜穿过黑洞视界或宇宙学视界时，对偶CFT的热力学量（包括熵）具有通常的特殊形式，用哈勃参数及其时间导数表示.对于Friedmann方程中的任意曲率参数$k$，我们得到了带电荷和宇宙学常数的CFT的广义Cardy-Verlinde公式.
We propose an effective model for an exponentially expanding universe in the brane-world scenario. The setup consists of a 5D black hole and a brane close to the black hole horizon. In case the brane acquires a specific configuration, which we deduce from stability arguments, the induced metric outside the black hole horizon on the brane becomes de Sitter in static coordinates. Studying the Einstein equations perturbatively we find the effective gravity on the brane at this level and derive the 4D gravitational constant. Considering a homogeneous and isotropic fluid in the corresponding FLRW c…
A dS brane on the boundary between two five-dimensional spacetimes is determined. We consider asymmetric scenarios with AdS${}_5$ vacua at each side of the dS brane; and as a result, a resonant mode inside of the spectrum of the gravitational fluctuations is found. We analyze the deviations to the Newton potential generated by the gravitational excitations, finding that, for scenarios with large values of the cosmological constants, the contribution of the resonant mode is exponentially suppressed. However, when one of the vacua is null, the resonant mode belongs to the light states set of the…
We investigate the four dimensional gravitational theories which admit homogeneous but anisotropic black brane solutions in asymptotically AdS space-time. The gravitational theories we consider are 1) Einstein-Maxwell-dilaton theory, and 2) Einstein-Maxwell-dilaton-axion theory with SL(2,R) symmetry. We obtain the solutions both analytically and numerically. Analytical solutions are obtained by perturbation from the isotropic solutions. Our solutions approach singular behavior at the horizon in the extremal limit but in non-extremal case, they are smooth everywhere. We also discuss how the thi…
Brane intersections, anti-de Sitter spacetimes and dual superconformal theories
我们构造了一类视界几何为adS_k x S^l x S^m x E^n的相交膜解.我们描述了所有这些解决方案是如何通过增加波和/或单极连接。所有的解在视界附近都表现出超对称性增强。此外，我们认为，这些空间上的弦论是对偶的特定超共形场论在二维的对称代数在所有情况下包含大N=4代数A_{gamma}。规范超重力的影响进行了讨论。
Dilatonic Brane-World Black Holes, Gravity Localization and Newton Constant
本文给出了d+1维双音引力的膜世界解族。它包括具有小宇宙学常数的平坦膜和（反）de Sitter膜，双光子膜世界黑洞（Schwarzschild-（反）de Sitter，Kerr等）。发现了这种膜周围的引力和电子微扰，表明在电子膜世界黑洞附近，引力可以定域为标准形式。估计了对牛顿定律的膜修正。提出了考虑耦合膜物质量子效应的建议。相应的有效作用改变了4d de Sitter墙的结构。简要讨论了红外和紫外波段四维牛顿常数RG流。
We obtain a four-dimensional supergravity with spontaneously broken supersymmetry allowing for de Sitter vacua by coupling a superspace action of minimal N=1, D=4 supergravity to a locally supersymmetric generalization of the Volkov-Akulov goldstino action describing the dynamics of a space-filling non-BPS 3-brane in N=1, D=4 superspace. To the quadratic order in the goldstino field the obtained action coincides with earlier constructions of supergravities with nilpotent superfields, while matching the higher-order contributions will require a non-linear redefinition of fields. In the unitary …
Spin 1/2 fields localization on an asymmetric dS${}_4$ scenario, where the brane interpolates between two spacetimes dS${}_5$ and AdS${}_5$, is determined. The bulk spinor is coupled to scalar field of the brane by a nonminimal Yukawa term compatible with the scenario's geometry. We show that, independently of wall's thickness, only one massless chiral mode is localized on the wall. The massive chiral modes follow a Schrödinger equation, whose potential has a mass gap determined by Yukawa constant, which is a generic property of this system. The fermions spectrum is defined bellow the gap, by …
Matrix Model For Polyakov Loops, String Field Theory In The Temporal Gauge, Winding String Condensation In Anti-de Sitter Space And Field Theory Of D-branes
We comment on approaches to the Cosmological Constant Problem in 4+1 dimensions, with the Standard Model fields confined to a 3-brane. We show that requiring maximal 4D symmetry only on this 3-brane (and not on all other 3-branes that foliate the 4+1-dimensional space) leads to a wide class of de Sitter solutions on the brane, with the Hubble constant sourced by the brane tension and a bulk scalar potential. For Poincaré symmetry on the brane, fine-tuning is always necessary. The de Sitter solutions are generated at a special dynamical point. Small deviations from this point are shown to grow …
We generalise the standard, flat p-brane solutions sourced by a dilaton and a form field, by taking the worldvolume to be a curved Einstein space, such as (anti-)de Sitter space. Our method is based on reducing the p-branes to domain walls and then allowing these domain walls to be curved. For de Sitter worldvolumes this extends some recently constructed warped de Sitter non-compactifications. We restrict our analysis to solutions that possess scaling behavior and demonstrate that these scaling solutions are near-horizon limits of a more general solution. Finally, our framework can equally be …
Within the framework of braneworlds, several interesting physical effects can be described in a wide range of energy scales, starting from high-energy physics to cosmology and low-energy physics. An usual way to generate a thick braneworld model relies in coupling a bulk scalar field to higher dimensional warped gravity. Quite recently, a novel braneworld was generated with the aid of a tachyonic bulk scalar field, having several remarkable properties. It comprises a regular and stable solution that contains a relevant 3--brane with de Sitter induced metric, arising as an exact solution to the…
Braneworld models may yield interesting effects ranging from high-energy physics to cosmology, or even some low-energy physics. Their mode structure modifies standard results in these physical realms that can be tested and used to set bounds on the models parameters. Now, to define braneworld deviations from standard 4D physics, a notion of matter and gravity localization on the brane is crucial. In this work we investigate the localization of universal massive scalar fields in a de Sitter thick tachyonic braneworld generated by gravity coupled to a tachyonic bulk scalar field. This braneworld…
We explore thick branes in $f(R,ϕ,X)$ gravity. We obtain the linear tensor perturbation equation of $f(R,ϕ,X)$ branes and show that the branes are stable against the tensor perturbations under the condition of $\frac{\partial f(R,ϕ,X)}{\partial R}>0$. In order to obtain thick brane solutions of the fourth-order field equations in this theory, we employ the reconstruction technique. We get exact solutions of the specific $f(R,ϕ,X)$ thick brane generated by a non-canonical scalar field. It is shown that the zero mode of the graviton for the thick brane is localized under certain conditions. This…
