Black hole thermalization rate from brane anti-brane model
Lifschytz, G
2004-01-01
We develop the quasi-particle picture for Schwarzchild and far from extremal black holes. We show that the thermalization equations of the black hole is recovered from the model of branes and anti-branes. This can also be viewed as a field theory explanation of the relationship between area and entropy for these black holes. As a by product the annihilation rate of branes and anti-branes is computed.
Black hole thermalization rate from brane anti-brane model
Energy Technology Data Exchange (ETDEWEB)
Lifschytz, Gilad E-mail: giladl@research.haifa.ac.il
2004-08-01
We develop the quasi-particle picture for Schwarzchild and far from extremal black holes. We show that the thermalization equations of the black hole is recovered from the model of branes and anti-branes. This can also be viewed as a field theory explanation of the relationship between area and entropy for these black holes. As a by product the annihilation rate of branes and anti-branes is computed. (author)
Soliton models for thick branes
Peyravi, Marzieh; Riazi, Nematollah; Lobo, Francisco S. N.
2016-05-01
In this work, we present new soliton solutions for thick branes in 4+1 dimensions. In particular, we consider brane models based on the sine-Gordon (SG), φ 4 and φ 6 scalar fields, which have broken Z2 symmetry in some cases and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacua. These vacua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighborhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the w^2 term in the expansion of the potential for the resulting Schrödinger-like equation, where w is the five-dimensional coordinate. It turns out that the φ ^4 brane is stable, while there are unstable modes for certain ranges of the model parameters in the SG and φ ^6 branes.
Soliton models for thick branes
Energy Technology Data Exchange (ETDEWEB)
Peyravi, Marzieh [Ferdowsi University of Mashhad, Department of Physics, School of Sciences, Mashhad (Iran, Islamic Republic of); Riazi, Nematollah [Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Lobo, Francisco S.N. [Faculdade de Ciencias da Universidade de Lisboa, Instituto de Astrofisica e Ciencias do Espaco, Lisbon (Portugal)
2016-05-15
In this work, we present new soliton solutions for thick branes in 4+1 dimensions. In particular, we consider brane models based on the sine-Gordon (SG), φ{sup 4} and φ{sup 6} scalar fields, which have broken Z{sub 2} symmetry in some cases and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacua. These vacua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighborhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the w{sup 2} term in the expansion of the potential for the resulting Schroedinger-like equation, where w is the five-dimensional coordinate. It turns out that the φ{sup 4} brane is stable, while there are unstable modes for certain ranges of the model parameters in the SG and φ{sup 6} branes. (orig.)
NS-branes in 5d brane world models
Park, Eun Kyung
2010-01-01
We study codimension-1 brane solutions of the 5d brane world models compactified on $S_1 / \\mathbb{Z}_2$. In string theoretical setup they suggest that the background branes located at orbifold fixed points should be NS-branes (in the five dimensional sense), rather than D-branes. Indeed, the existence of the background NS-branes is indispensable to obtain flat geometry $M_4 \\times S_1 / \\mathbb{Z}_2$ where $M_4$ represents the 4d Minkowski spacetime, and without these branes the 5d metric becomes singular everywhere. This result is very reminiscent of the $(p+3)$d effective string theory \\cite{1} where the NS-NS type $p$-brane is indispensable to obtain a flat geometry $R_2$ or $R_2 /\\mathbb{Z}_n$ on the transverse dimensions. Without this NS-NS type $p$-brane the 2d transverse space becomes a pin-shaped singular space. The correspondence between these two theories leads us to a conjecture that the whole flat backgrounds of the string theory inherently invovle the NS-branes implicitly in their ansatz, and he...
Soliton models for thick branes
Peyravi, Marzieh; Lobo, Francisco S N
2015-01-01
In this work, we present new soliton solutions for thick branes in $4+1$ dimensions. In particular, we consider brane models based on the sine-Gordon ($SG$), $\\varphi^{4}$ and $\\varphi^{6}$ scalar fields, which have broken $Z_{2}$ symmetry in some cases, and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacuua. These vacuua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighbourhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the $w^2$ term in the expansion of the potential for the resulting Schrodinger-like equation, where $w$ is the 5-dimensional coordinate. It turns out that the $\\phi^4$ brane is stable, while there are unstable modes for certain ranges of the model param...
Branes and integrable lattice models
Yagi, Junya
2016-01-01
This is a brief review of my work on the correspondence between four-dimensional $\\mathcal{N} = 1$ supersymmetric field theories realized by brane tilings and two-dimensional integrable lattice models. I explain how to construct integrable lattice models from extended operators in partially topological quantum field theories, and elucidate the correspondence as an application of this construction.
6-dimensional brane world model
Energy Technology Data Exchange (ETDEWEB)
Kanti, Panagiota; Madden, Richard; Olive, Keith A.
2001-08-15
We consider a 6-dimensional spacetime which is periodic in one of the extra dimensions and compact in the other. The periodic direction is defined by two 4-brane boundaries. Both static and nonstatic exact solutions, in which the internal spacetime has a constant radius of curvature, are derived. In the case of static solutions, the brane tensions must be tuned as in the 5-dimensional Randall-Sundrum model; however, no additional fine-tuning is necessary between the brane tensions and the bulk cosmological constant. By further relaxing the sole fine-tuning of the model, we derive nonstatic solutions, describing de Sitter or anti--de Sitter 4-dimensional spacetimes, that allow for the fixing of the interbrane distance and the accommodation of pairs of positive--negative and positive--positive tension branes. Finally, we consider the stability of the radion field in these configurations by employing small, time-dependent perturbations around the background solutions. In analogy with results drawn in five dimensions, the solutions describing a de Sitter 4-dimensional spacetime turn out to be unstable while those describing an anti--de Sitter geometry are shown to be stable.
Indian Academy of Sciences (India)
David Bailin
2003-02-01
I brieﬂy outline previous work on getting the (supersymmetric) standard model from string theory, and then describe two ecent attempts using D-branes. The ﬁrst uses D3- and D7- branes and gives a supersymmetric standard model with extra vector-like matter and an intermediate uniﬁcation scale. The second uses intersecting D4-branes and yields a non-supersymmetric spectrum with TeV-scale uniﬁcation.
Nishi, Masato
2016-07-01
We discuss the large mass hierarchy problem in a braneworld model which represents our acceleratively expanding universe. The Randall-Sundrum (RS) model with one extra warped dimension added to a flat four-dimensional space-time cannot describe our expanding universe. Here, we study instead the de Sitter thin brane model. This is described by the same action as that for the RS model, but the four-dimensional space-time on the branes is dS_4. We study the model for both the cases of positive five-dimensional cosmological constant Λ_5 and a negative one. In the positive Λ_5 case, the four-dimensional large hierarchy necessitates a five-dimensional large hierarchy, and we cannot get a natural explanation. On the other hand, in the negative Λ_5 case, the large hierarchy is naturally realized in the five-dimensional theory in the same manner as in the RS model. Moreover, another large hierarchy between the Hubble parameter and the Planck scale is realized by the O(10^2) hierarchy of the five-dimensional quantities. Finally, we find that the lightest mass of the massive Kaluza-Klein modes and the intervals of the mass spectrum are of order 10^2 GeV, which are the same as in the RS case and do not depend on the value of the Hubble parameter.
Configurational entropy in brane-world models
Energy Technology Data Exchange (ETDEWEB)
Correa, R.A.C. [CCNH, Universidade Federal do ABC, Santo Andre, SP (Brazil); Rocha, Roldao da [CMCC, Universidade Federal do ABC, Santo Andre, SP (Brazil); International School for Advanced Studies (SISSA), Trieste (Italy)
2015-11-15
In this work we investigate the entropic information on thick brane-world scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model and hence the brane-world entropic information measure is shown to be an accurate way for providing the most suitable range for the bulk AdS curvature, in particular from the informational content of physical solutions. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the configuration of the system, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy. (orig.)
Configurational entropy in brane-world models
Energy Technology Data Exchange (ETDEWEB)
Correa, R. A. C., E-mail: fis04132@gmail.com [CCNH, Universidade Federal do ABC, 09210-580, Santo André, SP (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [CMCC, Universidade Federal do ABC, 09210-580, Santo André, SP (Brazil); International School for Advanced Studies (SISSA), Via Bonomea 265, 34136, Trieste (Italy)
2015-11-02
In this work we investigate the entropic information on thick brane-world scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model and hence the brane-world entropic information measure is shown to be an accurate way for providing the most suitable range for the bulk AdS curvature, in particular from the informational content of physical solutions. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the configuration of the system, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy.
Configurational entropy in brane-world models
Correa, R. A. C.; da Rocha, Roldão
2015-11-01
In this work we investigate the entropic information on thick brane-world scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model and hence the brane-world entropic information measure is shown to be an accurate way for providing the most suitable range for the bulk AdS curvature, in particular from the informational content of physical solutions. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the configuration of the system, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy.
Brane Geometry and Dimer Models
He, Yang-Hui; Rodriguez-Gomez, Diego
2012-01-01
The field content and interactions of almost all known gauge theories in AdS_5/CFT_4 can be expressed in terms of dimer models or bipartite graphs drawn on a torus. Associated with the fundamental cell is a complex structure parameter tau_R. Based on the brane realization of these theories, we can specify a special Lagrangian (SLag) torus fibration that is the natural candidate to be identified as the torus on which the dimer lives. Using the metrics known in the literature, we compute the complex structure tau_G of this torus. For the theories on C^3 and the conifold and for orbifolds thereof tau_R = tau_G. However, for more complicated examples, we show that the two complex structures cannot be equal and yet, remarkably, differ only by a few percent. We leave the explanation for this extraordinary proximity as an open challenge.
Stellar models in Brane Worlds
Linares, Francisco X; Ureña-Lopez, L Arturo
2015-01-01
We consider here a full study of stellar dynamics from the brane-world point of view in the case of constant density and of a polytropic fluid. We start our study cataloguing the minimal requirements to obtain a compact object with a Schwarszchild exterior, highlighting the low and high energy limit, the boundary conditions, and the appropriate behavior of Weyl contributions inside and outside of the star. Under the previous requirements we show an extensive study of stellar behavior, starting with stars of constant density and its extended cases with the presence of nonlocal contributions. Finally, we focus our attention to more realistic stars with a polytropic equation of state, specially in the case of white dwarfs, and study their static configurations numerically. One of the main results is that the inclusion of the Weyl functions from braneworld models allow the existence of more compact configurations than within General Relativity.
Quantum billiards in multidimensional models with branes
Ivashchuk, V. D.; Melnikov, V. N.
2013-01-01
A gravitational D -dimensional model with l scalar fields and several forms is considered. When a cosmological-type diagonal metric is chosen, an electromagnetic composite brane ansatz is adopted and certain restrictions on the branes are imposed; the conformally covariant Wheeler–DeWitt (WDW) equation for the model is studied. Under certain restrictions asymptotic solutions to WDW equation are found in the limit of the formation of the billiard walls which reduce the problem to the so-called...
Brane Brick Models in the Mirror
Franco, Sebastian; Seong, Rak-Kyeong; Vafa, Cumrun
2016-01-01
Brane brick models are Type IIA brane configurations that encode the $2d$ $\\mathcal{N}=(0,2)$ gauge theories on the worldvolume of D1-branes probing toric Calabi-Yau 4-folds. We use mirror symmetry to improve our understanding of this correspondence and to provide a systematic approach for constructing brane brick models starting from geometry. The mirror configuration consists of D5-branes wrapping 4-spheres and the gauge theory is determined by how they intersect. We also explain how $2d$ $(0,2)$ triality is realized in terms of geometric transitions in the mirror geometry. Mirror symmetry leads to a geometric unification of dualities in different dimensions, where the order of duality is $n-1$ for a Calabi-Yau $n$-fold. This makes us conjecture the existence of a quadrality symmetry in $0d$. Finally, we comment on how the M-theory lift of brane brick models connects to the classification of $2d$ $(0,2)$ theories in terms of 4-manifolds.
Null fluid collapse in brane world models
Harko, Tiberiu
2013-01-01
The brane world description of our universe entails a large extra dimension and a fundamental scale of gravity that may be lower than the Planck scale by several orders of magnitude. An interesting consequence of this scenario occurs in the nature of spherically-symmetric vacuum solutions to the brane gravitational field equations, which often have properties quite distinct from the standard black hole solutions of general relativity. In this paper, the spherically-symmetric collapse on the brane world of four types of null fluid, governed by the barotropic, polytropic, strange quark "bag" model and Hagedorn equations of state, is investigated. In each case, we solve the approximate gravitational field equations, obtained in the high density limit, determine the equation which governs the formation of apparent horizons and investigate the conditions for the formation of naked singularities. Though, naively, one would expect the increased effective energy density on the brane to favor the formation of black ho...
Null fluid collapse in brane world models
Harko, Tiberiu; Lake, Matthew J.
2014-03-01
The brane world description of our Universe entails a large extra dimension and a fundamental scale of gravity that may be lower than the Planck scale by several orders of magnitude. An interesting consequence of this scenario occurs in the nature of spherically symmetric vacuum solutions to the brane gravitational field equations, which often have properties quite distinct from the standard black hole solutions of general relativity. In this paper, the spherically symmetric collapse on the brane world of four types of null fluid, governed by the barotropic, polytropic, strange quark "bag" model and Hagedorn equations of state, is investigated. In each case, we solve the approximate gravitational field equations, obtained in the high-density limit, determine the equation which governs the formation of apparent horizons and investigate the conditions for the formation of naked singularities. Though, naively, one would expect the increased effective energy density on the brane to favor the formation of black holes over naked singularities, we find that, for the types of fluid considered, this is not the case. However, the black hole solutions differ substantially from their general-relativistic counterparts and brane world corrections often play a role analogous to charge in general relativity. As an astrophysical application of this work, the possibility that energy emission from a Hagedorn fluid collapsing to form a naked singularity may be a source of GRBs in the brane world is also considered.
Isotropic singularity in inhomogeneous brane cosmological models
International Nuclear Information System (INIS)
We discuss the asymptotic dynamical evolution of spatially inhomogeneous brane-world cosmological models close to the initial singularity. By introducing suitable scale-invariant dependent variables and a suitable gauge, we write the evolution equations of the spatially inhomogeneous G2 brane cosmological models with one spatial degree of freedom as a system of autonomous first-order partial differential equations. We study the system numerically, and we find that there always exists an initial singularity, which is characterized by the fact that spatial derivatives are dynamically negligible. More importantly, from the numerical analysis we conclude that there is an initial isotropic singularity in all these spatially inhomogeneous brane cosmologies for a range of parameter values which include the physically important cases of radiation and a scalar field source. The numerical results are supported by a qualitative dynamical analysis and a calculation of the past asymptotic decay rates. Although the analysis is local in nature, the numerics indicate that the singularity is isotropic for all relevant initial conditions. Therefore this analysis, and a preliminary investigation of general inhomogeneous (G0) models, indicates that it is plausible that the initial singularity is isotropic in spatially inhomogeneous brane-world cosmological models and consequently that brane cosmology naturally gives rise to a set of initial data that provide the conditions for inflation to subsequently take place
More on divergences in brane world models
Smolyakov, Mikhail N
2013-01-01
In this note a model in a space-time with compact extra dimension, describing five-dimensional fermion fields interacting with electromagnetic field localized on a brane, is presented. This model can be considered as a toy model for examining possible consequences of localization of gauge fields on a brane. It is shown that in the limit of infinite extra dimension the lowest order amplitudes of some processes in the resulting four-dimensional effective theory are divergent. Such a "localization catastrophe" can be inherent to more realistic bane world models with infinite extra dimension.
Motion in Brane World Models The Bazanski Approach
Kahil, M E
2007-01-01
Recently, path equations have been obtained for charged, spinning objects in brane world models, using a modified Bazanski Lagrangian. In this study, path deviation equations of extended objects are derived. The significance of moving extended objects in brane world models is examined. Motion in non- symmetric brane world models is also considered.
Solar system tests of brane world models
Boehmer, Christian G; Lobo, Francisco S N
2008-01-01
The classical tests of general relativity (perihelion precession, deflection of light, and the radar echo delay) are considered for the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) solution of the spherically symmetric static vacuum field equations in brane world models. For this solution the metric in the vacuum exterior to a brane world star is similar to the Reissner-Nordstrom form of classical general relativity, with the role of the charge played by the tidal effects arising from projections of the fifth dimension. The existing observational solar system data on the perihelion shift of Mercury, on the light bending around the Sun (obtained using long-baseline radio interferometry), and ranging to Mars using the Viking lander, constrain the numerical values of the bulk tidal parameter and of the brane tension.
Kirpichnikov, D V
2013-01-01
We discuss the one loop effects of massless fermion fields on the low energy vector brane-to-brane propagators in the framework of two QED brane-world scenarios. We show that one loop photon brane-to-brane propagator has a power law pathologic IR divergences in the 5D QED brane-world model with gap between the vector zero mode and continuous states. We also find that bulk fermions do not give rise to IR divergences in a photon brane-to-brane Green's function at least at the one loop level in the framework of 6D QED brane model with gapless mass spectrum between vector zero mode and higher states.
Thick brane world model from perfect fluid
Ivashchuk, V D
2001-01-01
A (1 + d)-dimensional thick "brane world" model with varying Lambda-term is considered. The model is generalized to the case of a chain of Ricci-flat internal spaces when the matter source is an anisotropic perfect fluid. The "horizontal" part of potential is obtained in the Newtonian approximation. In the multitemporal case (with a Lambda-term) a set of equations for potentials is presented.
The landscape of intersecting brane models
Energy Technology Data Exchange (ETDEWEB)
Douglas, Michael R. [NHETC and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08855-0849 (United States); Taylor, Washington [Center for Theoretical Physics, MIT, Cambridge, MA 02139 (United States)
2007-01-15
We develop tools for analyzing the space of intersecting brane models. We apply these tools to a particular T{sup 6}/Z{sup 2}{sub 2} orientifold which has been used for model building. We prove that there are a finite number of intersecting brane models on this orientifold which satisfy the Diophantine equations coming from supersymmetry. We give estimates for numbers of models with specific gauge groups, which we confirm numerically. We analyze the distributions and correlations of intersection numbers which characterize the numbers of generations of chiral fermions, and show that intersection numbers are roughly independent, with a characteristic distribution which is peaked around 0 and in which integers with fewer divisors are mildly suppressed. As an application, the number of models containing a gauge group SU(3) x SU(2) x U(1) or SU(4) x SU(2) x SU(2) and 3 generations of appropriate types of chiral matter is estimated to be order O(10), in accord with previous explicit constructions. As another application of the methods developed in the paper, we construct a new pair of 3-generation SU(4) x SU(2) x SU(2) Pati-Salam models using intersecting branes. We conclude with a description of how this analysis can be generalized to a broader class of Calabi-Yau orientifolds, and a discussion of how the numbers of IBM's are related to numbers of stabilized vacua.
The landscape of intersecting brane models
Douglas, Michael R.; Taylor, Washington
2007-01-01
We develop tools for analyzing the space of intersecting brane models. We apply these tools to a particular T6/Bbb Z22 orientifold which has been used for model building. We prove that there are a finite number of intersecting brane models on this orientifold which satisfy the Diophantine equations coming from supersymmetry. We give estimates for numbers of models with specific gauge groups, which we confirm numerically. We analyze the distributions and correlations of intersection numbers which characterize the numbers of generations of chiral fermions, and show that intersection numbers are roughly independent, with a characteristic distribution which is peaked around 0 and in which integers with fewer divisors are mildly suppressed. As an application, the number of models containing a gauge group SU(3) × SU(2) × U(1) or SU(4) × SU(2) × SU(2) and 3 generations of appropriate types of chiral matter is estimated to be order Script O(10), in accord with previous explicit constructions. As another application of the methods developed in the paper, we construct a new pair of 3-generation SU(4) × SU(2) × SU(2) Pati-Salam models using intersecting branes. We conclude with a description of how this analysis can be generalized to a broader class of Calabi-Yau orientifolds, and a discussion of how the numbers of IBM's are related to numbers of stabilized vacua.
Galactic rotation curves and brane world models
Rahaman, F; De Benedictis, A; Usmani, A A; Ray, Saibal
2008-01-01
In the present investigation flat rotational curves of the galaxies are considered under the framework of brane-world models where the 4d effective Einstein equation has extra terms which arise from the embedding of the 3-brane in the $5d$ bulk. It has been shown here that these long range bulk gravitational degrees of freedom can act as a mechanism to yield the observed galactic rotation curves without the need for dark matter. The present model has the advantage that the observed rotation curves result solely from well-established non-local effects of gravitation, such as dark radiation and dark pressure under a direct use of the condition of flat rotation curves and does not invoke any exotic matter field.
Gravity in the brane-world for two-branes model with stabilized modulus
Energy Technology Data Exchange (ETDEWEB)
Tanaka, Takahiro; Montes, Xavier
2000-08-28
We present a complete scheme to discuss linear perturbations in the two-branes model of the Randall and Sundrum scenario with the stabilization mechanism proposed by Goldberger and Wise. We confirm that under the approximation of zero-mode truncation the induced metric on the branes reproduces that of the usual 4-dimensional Einstein gravity. We also present formulas to evaluate the mass spectrum and the contribution to the metric perturbations from all the Kaluza-Klein modes. We also conjecture that the model has tachyonic modes unless the background configuration for the bulk scalar field introduced to stabilize the distance between the two branes is monotonic in the fifth dimension.
Bouncing Model in Brane World Theory
Maier, Rodrigo; Soares, Ivano Damião
2013-01-01
We examine the nonlinear dynamics of a closed Friedmann-Robertson-Walker universe in the framework of Brane World formalism with a timelike extra dimension. In this scenario, the Friedmann equations contain additional terms arising from the bulk-brane interaction which provide a concrete model for nonsingular bounces in the early phase of the Universe. We construct a nonsingular cosmological scenario sourced with dust, radiation and a cosmological constant. The structure of the phase space shows a nonsingular orbit with two accelerated phases, separated by a smooth transition corresponding to a decelerated expansion. Given observational parameters we connect such phases to a primordial accelerated phase, a soft transition to Friedmann (where the classical regime is valid), and a graceful exit to a de Sitter accelerated phase.
Moduli stabilization in higher dimensional brane models
Energy Technology Data Exchange (ETDEWEB)
Flachi, Antonino; Pujolas, Oriol [IFAE, Campus UAB, 08193 Bellaterra, Barcelona (Spain)]. E-mail: pujolas@ifae.es; Garriga, Jaume [IFAE, Campus UAB, 08193 Bellaterra, Barcelona (Spain); Departament de Fisica Fonamental and C.E.R. en Astrofisica, Fisica de Particules i Cosmologia Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Tanaka, Takahiro [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford MA 02155 (United States); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
2003-08-01
We consider a class of warped higher dimensional brane models with topology M x {sigma} x S{sup 1}/Z{sub 2}, where {sigma} is a D2 dimensional manifold. Two branes of co-dimension one are embedded in such a bulk space-time and sit at the orbifold fixed points. We concentrate on the case where an exponential warp factor (depending on the distance along the orbifold) accompanies the Minkowski M and the internal space {sigma} line elements. We evaluate the moduli effective potential induced by bulk scalar fields in these models, and we show that generically this can stabilize the size of the extra dimensions. As an application, we consider a scenario where supersymmetry is broken not far below the cutoff scale, and the hierarchy between the electroweak and the effective Planck scales is generated by a combination of redshift and large volume effects. The latter is efficient due to the shrinking of {sigma} at the negative tension brane, where matter is placed. In this case, we find that the effective potential can stabilize the size of the extra dimensions (and the hierarchy) without fine tuning, provided that the internal space {sigma} is flat. (author)
Modular symmetry in magnetized/intersecting D-brane models
Kobayashi, Tatsuo; Uemura, Shohei
2016-01-01
We study the modular symmetry in four-dimensional low-energy effective field theory, which is derived from type IIB magnetized D-brane models and type IIA intersecting D-brane models. We analyze modular symmetric behaviors of perturbative terms and non-perturbative terms induced by D-brane instanton effects. Anomalies are also investigated and such an analysis on anomalies suggests corrections in effective field theory.
Randall-Sundrum model with {lambda}<0 and bulk brane viscosity
Energy Technology Data Exchange (ETDEWEB)
Lepe, Samuel [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4950, Valparaiso (Chile); Pena, Francisco [Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Universidad de la Frontera, Avda. Francisco Salazar 01145, Casilla 54-D, Temuco (Chile); Saavedra, Joel [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4950, Valparaiso (Chile)], E-mail: joel.saavedra@ucv.cl
2008-04-17
We study the effect of the inclusion of bulk brane viscosity on brane world (BW) cosmology in the framework of the Eckart's theory, we focus in the Randall-Sundrum model with negative tension on the brane.
Galactic rotation curves in brane world models
Gergely, L Á; Dwornik, M; Kupi, G; Keresztes, Z
2011-01-01
In the braneworld scenario the four dimensional effective Einstein equation has extra source terms, which arise from the embedding of the 3-brane in the bulk. These non-local effects, generated by the free gravitational field of the bulk, may provide an explanation for the dynamics of the neutral hydrogen clouds at large distances from the galactic center, which is usually explained by postulating the existence of the dark matter. In the present paper we consider the asymptotic behavior of the galactic rotation curves in the brane world models, and we compare the theoretical results with observations of both High Surface Brightness and Low Surface Brightness galaxies. For the chosen sample of galaxies we determine first the baryonic parameters by fitting the photometric data to the adopted galaxy model; then we test the hypothesis of the Weyl fluid acting as dark matter on the chosen sample of spiral galaxies by fitting the tangential velocity equation of the combined baryonic-Weyl model to the rotation curve...
Split supersymmetry in brane models
Indian Academy of Sciences (India)
Ignatios Antoniadis
2006-11-01
Type-I string theory in the presence of internal magnetic fields provides a concrete realization of split supersymmetry. To lowest order, gauginos are massless while squarks and sleptons are superheavy. For weak magnetic fields, the correct Standard Model spectrum guarantees gauge coupling unification with sin2 W = 3/8 at the com-pactification scale of GUT ≃ 2 × 1016 GeV. I discuss mechanisms for generating gaugino and higgsino masses at the TeV scale, as well as generalizations to models with split extended supersymmetry in the gauge sector.
Clustering of galaxies in brane world models
Hameeda, Mir; Faizal, Mir; Ali, Ahmed Farag
2016-04-01
In this paper, we analyze the clustering of galaxies using a modified Newtonian potential. This modification of the Newtonian potential occurs due to the existence of extra dimensions in brane world models. We will analyze a system of galaxies interacting with each other through this modified Newtonian potential. The partition function for this system of galaxies will be calculated, and this partition function will be used to calculate the free energy of this system of galaxies. The entropy and the chemical potential for this system will also be calculated. We will derive explicit expression for the clustering parameter for this system. This parameter will determine the behavior of this system, and we will be able to express various thermodynamic quantities using this clustering parameter. Thus, we will be able to explicitly analyze the effect that modifying the Newtonian potential can have on the clustering of galaxies. We also analyse the effect of extra dimensions on the two-point functions between galaxies.
Clustering of Galaxies in Brane World Models
Hameeda, Mir; Ali, Ahmed Farag
2015-01-01
In this paper, we analyze the clustering of galaxies using a modified Newtonian potential. This modification of the Newtonian potential occurs due to the existence of extra dimensions in brane world models. We will analyze a system of galaxies interacting with each other through this modified Newtonian potential. The partition function for this system of galaxies will be calculated, and this partition function will be used to calculate the free energy of this system of galaxies. The entropy and the chemical potential for this system will also be calculated. We will derive an explicit expression for the clustering parameter for this system. This parameter will determine the behavior of this system, and we will be able to express various thermodynamic quantities using this clustering parameter. Thus, we will be able to explicitly analyze the effect that modifying the Newtonian potential can have on the clustering of galaxies.
Statistics in the landscape of intersecting brane models
Energy Technology Data Exchange (ETDEWEB)
Gmeiner, Florian [NIKHEF, Amsterdam (Netherlands)
2008-08-15
An approach towards a statistical survey of four-dimensional supersymmetric vacua in the string theory landscape is described and illustrated with three examples of ensembles of intersecting D-brane models. The question whether it is conceivable to make predictions based on statistical distributions is discussed. Especially interesting in this context are possible correlations between low energy observables. As an example we look at correlations between properties of the gauge sector of intersecting D-brane models and Gepner model constructions. (orig.)
Discrete flavor symmetries in D-brane models
Marchesano, Fernando; Vázquez-Mercado, Liliana
2013-01-01
We study the presence of discrete flavor symmetries in D-brane models of particle physics. By analyzing the compact extra dimensions of these models one can determine when such symmetries exist both in the context of intersecting and magnetized D-brane constructions. Our approach allows to distinguish between approximate and exact discrete symmetries, and it can be applied to compactification manifolds with continuous isometries or to manifolds that only contain discrete isometries, like Calabi-Yau three-folds. We analyze in detail the class of rigid D-branes models based on a Z_2 x Z'_2 toroidal orientifold, for which the flavor symmetry group is either the dihedral group D_4 or tensor products of it. We construct explicit Pati-Salam examples in which families transform in non-Abelian representations of the flavor symmetry group, constraining Yukawa couplings beyond the effect of massive U(1) D-brane symmetries.
Universe acceleration in brane world models
Chiou-Lahanas, C.; Diamandis, G. A.; Georgalas, B. C.
2014-05-01
We examine the cosmology induced on a brane moving in the background of a five-dimensional black hole, solution of the string effective action. The evolution, determined by the Israel junction conditions is found to be compatible with an accelerating universe with the present day acceleration coming after a decelerating phase. The possible species of the energy-momentum tensor, localized on the brane, for these solutions to be valid are discussed.
Universe Acceleration in Brane World Models
Chiou-Lahanas, C; Georgalas, B C
2013-01-01
We examine the cosmology induced on a brane moving in the background of a five-dimensional black hole, solution of the string effective action. The evolution determined by the Israel junction conditions is found to be compatible with an accelerating universe with the present day acceleration coming after a decelerating phase. The conditions imposed on the energy-momentum tensor, localized on the brane, for these solutions to be valid are discussed.
Flavor structure in D-brane models: Majorana neutrino masses
Hamada, Yuta; Kobayashi, Tatsuo; Uemura, Shohei
2014-05-01
We study the flavor structure in intersecting D-brane models. We study anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino masses, which can be generated by D-brane instanton effects. It is found that a certain pattern of mass matrix is obtained and the cyclic permutation symmetry remains unbroken. As a result, trimaximal mixing matrix can be realized if Dirac neutrino mass and charged lepton mass matrices are diagonal.
Flavor structure in D-brane models: Majorana neutrino masses
Hamada, Yuta; Uemura, Shohei
2014-01-01
We study the flavor structure in intersecting D-brane models. We study anomalies of the discrete flavor symmetries. We analyze the Majorana neutrino masses, which can be generated by D-brane instanton effects. It is found that a certain pattern of mass matrix is obtained and the cyclic permutation symmetry remains unbroken. As a result, trimaximal mixing matrix can be realized if Dirac neutrino mass and charged lepton mass matrices are diagonal.
Sarrazin, M; Sarrazin, Michael; Petit, Fabrice
2004-01-01
In recent few years, there has been a number of papers devoted to the brane world theories which appear to be of potential interest for explaining several puzzling physical phenomena. Inspired from those models, we propose in this paper to consider relevant extensions of the Dirac and Pauli equations for a two brane universe. This model assumes that the branes are embedded in a 5D bulk where the fifth dimension is restricted to only two points. In previous attempts to describe quantum effects involving branes, graviton oscillations have been suggested as well as the possibility for highly energetic particles to escape into the 5D bulk. In this paper, we predict that usual matter particles can oscillate between the two branes as well. It is suggested that this phenomenon, which is a low energy one, might be enhanced using electromagnetic fields and could perhaps be demonstrated at a laboratory scale.
Warm inflation in the DGP brane-world model
Energy Technology Data Exchange (ETDEWEB)
Campo, Sergio dek [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile)], E-mail: sdelcamp@ucv.cl; Herrera, Ramon [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile)], E-mail: ramon.herrera@ucv.cl
2007-09-20
Warm inflationary universe models on a warped Dvali-Gabadadze-Porrati brane are studied. General conditions required for these models to be realizable are derived and discussed. By using an effective exponential potential we develop models for constant and variable dissipation coefficient ratio r=({gamma})/(3H) . We use recent astronomical observations for constraining the parameters appearing in our models.
D3-Brane Model Building and the Supertrace Rule.
Bena, Iosif; Graña, Mariana; Kuperstein, Stanislav; Ntokos, Praxitelis; Petrini, Michela
2016-04-01
A common way to obtain standard-model-like Lagrangians in string theory is to place D3-branes inside flux compactifications. The bosonic and fermionic masses and couplings of the resulting gauge theory are determined by the ten-dimensional metric and the fluxes, respectively, and the breaking of supersymmetry is soft. However, not any soft-supersymmetry-breaking Lagrangian can be obtained this way since the string theory equations of motion impose certain relations between the soft couplings. We show that for D3-branes in background fluxes, these relations imply that the sums of the squares of the boson and of the fermion masses are equal and that, furthermore, one- and two-loop quantum corrections do not spoil this equality. This makes the use of D3-branes for constructing computationally controllable models for physics beyond the standard model problematic. PMID:27104696
D3-Brane Model Building and the Supertrace Rule.
Bena, Iosif; Graña, Mariana; Kuperstein, Stanislav; Ntokos, Praxitelis; Petrini, Michela
2016-04-01
A common way to obtain standard-model-like Lagrangians in string theory is to place D3-branes inside flux compactifications. The bosonic and fermionic masses and couplings of the resulting gauge theory are determined by the ten-dimensional metric and the fluxes, respectively, and the breaking of supersymmetry is soft. However, not any soft-supersymmetry-breaking Lagrangian can be obtained this way since the string theory equations of motion impose certain relations between the soft couplings. We show that for D3-branes in background fluxes, these relations imply that the sums of the squares of the boson and of the fermion masses are equal and that, furthermore, one- and two-loop quantum corrections do not spoil this equality. This makes the use of D3-branes for constructing computationally controllable models for physics beyond the standard model problematic.
Decompactifications and massless D-branes in hybrid models
Aspinwall, Paul S.; Ronen Plesser, M.
2010-07-01
A method of determining the mass spectrum of BPS D-branes in any phase limit of a gauged linear sigma model is introduced. A ring associated to monodromy is defined and one considers K-theory to be a module over this ring. A simple but interesting class of hybrid models with Landau-Ginzburg fibres over {mathbb{P}^n} are analyzed using special Kähler geometry and D-brane probes. In some cases the hybrid limit is an infinite distance in moduli space and corresponds to a decompactification. In other cases the hybrid limit isat a finite distance and acquires massless D-branes. An example studied appears to correspond to a novel theory of supergravity with an SU(2) gauge symmetry where the gauge and gravitational couplings are necessarily tied to each other.
Classical tests of general relativity in brane world models
Boehmer, Christian G; Harko, Tiberiu; Lobo, Francisco S N
2009-01-01
The classical tests of general relativity (perihelion precession, deflection of light, and the radar echo delay) are considered for several spherically symmetric static vacuum solutions in brane world models. Generally, the spherically symmetric vacuum solutions of the brane gravitational field equations have properties quite distinct as compared to the standard black hole solutions of general relativity. As a first step a general formalism that facilitates the analysis of general relativistic Solar System tests for any given spherically symmetric metric is developed. It is shown that the existing observational Solar System data on the perihelion shift of Mercury, on the light bending around the Sun (obtained using long-baseline radio interferometry), and ranging to Mars using the Viking lander, constrain the numerical values of the parameters of the specific models. Hence Solar System tests represent very convenient and efficient tools to test the viability of the different black hole solutions in brane worl...
Phenomenological Lagrangians, gauge models and branes
Zheltukhin, A A
2016-01-01
Phenomenological Lagrangians for physical systems with spontaneously broken symmetries are reformulated in terms of gauge field theory. Description of the Dirac $p$-branes in terms of the Yang-Mills-Cartan gauge multiplets interacting with gravity, is proved to be equivalent to their description as a closed dynamical system with the symmetry $ISO(1,D-1)$ spontaneously broken to $ISO(1,p)\\times SO(D-p-1)$.
Simple brane-world inflationary models — An update
Okada, Nobuchika; Okada, Satomi
2016-05-01
In the light of the Planck 2015 results, we update simple inflationary models based on the quadratic, quartic, Higgs and Coleman-Weinberg potentials in the context of the Randall-Sundrum brane-world cosmology. Brane-world cosmological effect alters the inflationary predictions of the spectral index (ns) and the tensor-to-scalar ratio (r) from those obtained in the standard cosmology. In particular, the tensor-to-scalar ratio is enhanced in the presence of the 5th dimension. In order to maintain the consistency with the Planck 2015 results for the inflationary predictions in the standard cosmology, we find a lower bound on the five-dimensional Planck mass (M5). On the other hand, the inflationary predictions laying outside of the Planck allowed region can be pushed into the allowed region by the brane-world cosmological effect with a suitable choice of M5.
Simple brane-world inflationary models: an update
Okada, Nobuchika
2015-01-01
In the light of the Planck 2015 results, we update simple inflationary models based on the quadratic, quartic, Higgs and Coleman-Weinberg potentials in the context of the Randall-Sundrum brane-world cosmology. Brane-world cosmological effect alters the inflationary predictions of the spectral index ($n_s$) and the tensor-to-scalar ratio ($r$) from those obtained in the standard cosmology. In particular, the tensor-to-scalar ratio is enhanced in the presence of the 5th dimension. In order to maintain the consistency with the Planck 2015 results for the inflationary predictions in the standard cosmology, we find a lower bound on the five-dimensional Planck mass. On the other hand, the inflationary predictions laying outside of the Planck allowed region can be pushed into the allowed region by the brane-world cosmological effect.
Comments on SUSY Inflation Models on the Brane
Lee, Lu-Yun; Cheung, Kingman; Lin, Chia-Min
In this paper we consider a class of inflation models on the brane where the dominant part of the inflaton scalar potential does not depend on the inflaton field value during inflation. In particular, we consider supernatural inflation, its hilltop version, A-term inflation, and supersymmetric (SUSY) D- and F-term hybrid inflation on the brane. We show that the parameter space can be broadened, the inflation scale generally can be lowered, and still possible to have the spectral index ns = 0.96.
Comments on SUSY inflation models on the brane
Lee, Lu-Yun; Lin, Chia-Min
2009-01-01
In this paper we consider a class of inflation models on the brane where the dominant part of the inflaton scalar potential does not depend on the inflaton field value during inflation. In particular, we consider supernatural inflation, its hilltop version, A-term inflation, and supersymmetric (SUSY) D- and F-term hybrid inflation on the brane. We show that the parameter space can be broadened, the inflation scale generally can be lowered, and still possible to have the spectral index $n_s=0.96$.
Cosmological evolution in a two-brane warped geometry model
Kumar, Sumit; SenGupta, Soumitra
2014-01-01
We study an effective 4-dimensional scalar-tensor field theory, originated from an underlying brane-bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton potential naturally emerges from the radion energy-momentum tensor which in turn results into an inflationary model of the Universe on the visible brane that is consistent with the recent results from the Planck's experiment. The dynamics of modulus stabilization from the inflaton rolling condition is demonstrated. The implications of our results in the context of recent BICEP2 results are also discussed.
Angular momentum of a brane-world model
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In this paper we discuss the properties of the general covariant angular momentum of a fivedimensional brane-world model. Through calculating the total angular momentum of this model, we are able to analyze the properties of the total angular momentum in the inflationary RS model. We show that the space-like components of the total angular momentum of the inflationary RS model are all zero while the others are non-zero, which agrees with the results from ordinary RS model.
Angular Momentum of a Brane-world Model
Jia, Bei; Zhang, Peng-Ming
2008-01-01
In this paper we discuss the properties of the general covariant angular momentum of a five-dimensional brane-world model. Through calculating the total angular momentum of this model, we are able to analyze the properties of the total angular momentum in the inflationary RS model. We show that the space-like components of the total angular momentum of are all zero while the others are non-zero, which agrees with the results from ordinary RS model.
Some phenomenology of intersecting D-brane models
Energy Technology Data Exchange (ETDEWEB)
Kane, Gordon L.; Kumar, Piyush; /Michigan U., MCTP; Lykken, Joseph D.; /Fermilab; Wang, Ting T.; /Michigan U., MCTP
2004-11-01
We present some phenomenology of a new class of intersecting D-brane models. Soft SUSY breaking terms for these models are calculated in the complex structure (u)-moduli dominant SUSY breaking approach (in type IIA). In this case, the dependence of the soft terms on the Yukawas and Wilson lines drops out. These soft terms have a different pattern compared to the usual heterotic string models. Phenomenological implications for dark matter are discussed.
The Standard Model from stable intersecting brane world orbifolds
Energy Technology Data Exchange (ETDEWEB)
Blumenhagen, Ralph E-mail: blumenha@physik.hu-berlin.de; Koers, Boris E-mail: koers@physik.hu-berlin.de; Luest, Dieter E-mail: luest@physik.hu-berlin.de; Ott, Tassilo E-mail: ott@physik.hu-berlin.de
2001-11-19
We analyze the perturbative stability of non-supersymmetric intersecting brane world models on tori. Besides the dilaton tadpole, a dynamical instability in the complex structure moduli space occurs at string disc level, which drives the background geometry to a degenerate limit. We show that in certain orbifold models this latter instability is absent as the relevant moduli are frozen. We construct explicit examples of such orbifold intersecting brane world models and discuss the phenomenological implications of a three generation Standard Model which descends naturally from an SU(5) GUT theory. It turns out that various phenomenological issues require the string scale to be at least of the order of the GUT scale. As a major difference compared to the Standard Model, some of the Yukawa couplings are excluded so that the standard electroweak Higgs mechanism with a fundamental Higgs scalar is not realized in this set-up.
Higher Curvature Brane Corrections to the DGP Model
Cadoni, Mariano
2008-01-01
We investigate the Dvali-Gabadadze-Porrati (DGP) model corrected by higher curvature brane terms. We show that these corrections have a dramatic impact on the spectrum of the model at the linearized level. Owing to the presence of higher derivatives in the field equations very massive ghost excitations with mass of order of Planck mass are generated in the ordinary branch of the model. These excitations describe an instability of Minkowski vacuum with time-scale of order of the Hubble time. At large distances these tachyonic excitations are expected to decouple from brane-localized matter. Our modified DGP model represents therefore a very promising framework for solving of the cosmological constant problem, in which Planck-scale physics is responsible for the elementary excitations driving the accelerated expansion of the universe, but the time-scale of the instability is settled by gravitational physics at large scales.
Higgs-radion mixing in stabilized brane world models
Boos, Edward E.; Bunichev, Viacheslav E.; Perfilov, Maxim A.; Smolyakov, Mikhail N.; Volobuev, Igor P.
2015-11-01
We consider a quartic interaction of the Higgs and Goldberger-Wise fields, which connects the mechanism of the extra dimension size stabilization with spontaneous symmetry breaking on our brane and gives rise to a coupling of the Higgs field to the radion and its KK tower. We estimate a possible influence of this coupling on the Higgs-radion mixing and study restrictions on model parameters from the LHC data.
Warped Higgsless Models with IR-Brane Kinetic Terms
Davoudiasl, H; Lillie, Benjamin Huntington; Rizzo, T G
2004-01-01
We examine a warped Higgsless $SU(2)_L\\times SU(2)_R\\times U(1)_{B-L}$ model in 5--$d$ with IR(TeV)--brane kinetic terms. It is shown that adding a brane term for the $U(1)_{B-L}$ gauge field does not affect the scale ($\\sim 2-3$ TeV) where perturbative unitarity in $W_L^+ W_L^- \\to W_L^+ W_L^-$ is violated. This term could, however, enhance the agreement of the model with the precision electroweak data. In contrast, the inclusion of a kinetic term corresponding to the $SU(2)_D$ custodial symmetry of the theory delays the unitarity violation in $W_L^\\pm$ scattering to energy scales of $\\sim 6-7$ TeV for a significant fraction of the parameter space. This is about a factor of 4 improvement compared to the corresponding scale of unitarity violation in the Standard Model without a Higgs. We also show that null searches for extra gauge bosons at the Tevatron and for contact interactions at LEP II place non-trivial bounds on the size of the IR-brane terms.
String and Brane Models with Spontaneously/Dynamically Induced Tension
Guendelman, E I; Nissimov, Emil R; Pacheva, S; Guendelman, Eduardo; Kaganovich, Alexander; Nissimov, Emil; Pacheva, Svetlana
2002-01-01
We study in some detail the properties of a previously proposed new class of string and brane models whose world-sheet (world-volume) actions are built with a modified reparametrization-invariant measure of integration and which do not contain any ad hoc dimensionfull parameters. The ratio of the new and the standard Riemannian integration measure densities plays the role of a dynamically generated string/brane tension. The latter is identified as (the magnitude of) an effective (non-Abelian) electric field-strength on the world-sheet/world-volume obeying the standard Gauss-law constraint. As a result a simple classical mechanism for confinement via strings is proposed.
Equation-of-state formalism for dark energy models on the brane and the future of brane universes
Energy Technology Data Exchange (ETDEWEB)
Astashenok, Artyom V.; Yurov, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, Kaliningrad (Russian Federation); Elizalde, Emilio [Facultat de Ciencies, Consejo Superior de Investigaciones Cientificas, ICE/CSIC and IEEC Campus UAB, Bellaterra, Barcelona (Spain); Odintsov, Sergei D. [Facultat de Ciencies, Consejo Superior de Investigaciones Cientificas, ICE/CSIC and IEEC Campus UAB, Bellaterra, Barcelona (Spain); Institucio Catalana de Recerca i Estudis Avancats (ICREA), Barcelona (Spain)
2012-12-15
Brane dark energy cosmologies, leading to various possible evolutions of our universe, are investigated. The discussion shows that while all these models can be made arbitrarily close to the standard {Lambda}CDM cosmology at present, their future evolutions can be very different, even diverge with time in a number of ways. This includes asymptotic de-Sitter evolution, Little Rip with dissolution of bound structures, and various possible singularities, as the Big Rip, a sudden future singularity (Type II), and Type III and Type IV cases. Specifically, some interesting effects coming from the brane tension are investigated. It is shown, in particular, that the Little Rip occurs faster on the brane model than in usual FRW cosmology. In the asymptotic de-Sitter regime the influence of the brane tension leads to a deviation of the value of the effective cosmological constant from that corresponding to ordinary dark energy. As a consequence, the value of the inertial force from the accelerating expansion can greatly exceed the corresponding inertial force in ordinary cosmological models. (orig.)
Configurational entropy in $f(R,T)$ brane models
Correa, R A C
2015-01-01
In this work we investigate generalized theories of gravity in the so-called configurational entropy (CE) context. We show, by means of this information-theoretical measure, that a stricter bound on the parameter of $f(R,T)$ brane models arises from the CE. We find that these bounds are characterized by a valley region in the CE profile, where the entropy is minimal. We argue that the CE measure can open a new role and an important additional approach to select parameters in modified theories of gravitation.
Cosmological evolution in a two-brane warped geometry model
Directory of Open Access Journals (Sweden)
Sumit Kumar
2015-07-01
Full Text Available We study an effective 4-dimensional scalar–tensor field theory, originated from an underlying brane–bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton potential naturally emerges from the radion energy–momentum tensor which in turn results in an inflationary model of the Universe on the visible brane that is consistent with the recent results from the Planck's experiment. The dynamics of modulus stabilization from the inflaton rolling condition is demonstrated. The implications of our results in the context of recent BICEP2 results are also discussed.
Cosmological evolution in a two-brane warped geometry model
Energy Technology Data Exchange (ETDEWEB)
Kumar, Sumit, E-mail: sumit@ctp-jamia.res.in [Center For Theoretical Physics, Jamia Millia Islamia, New Delhi 110025 (India); Sen, Anjan A., E-mail: aasen@jmi.ac.in [Center For Theoretical Physics, Jamia Millia Islamia, New Delhi 110025 (India); SenGupta, Soumitra, E-mail: tpssg@iacs.res.in [Department of Theoretical Physics, Indian Association for the Cultivation of Science, Kolkata 700032 (India)
2015-07-30
We study an effective 4-dimensional scalar–tensor field theory, originated from an underlying brane–bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton potential naturally emerges from the radion energy–momentum tensor which in turn results in an inflationary model of the Universe on the visible brane that is consistent with the recent results from the Planck's experiment. The dynamics of modulus stabilization from the inflaton rolling condition is demonstrated. The implications of our results in the context of recent BICEP2 results are also discussed.
Configurational entropy in f(R,T) brane models
Energy Technology Data Exchange (ETDEWEB)
Correa, R.A.C. [Universidade Federal do ABC, CCNH, Santo Andre, Sao Paulo (Brazil); Moraes, P.H.R.S. [ITA, Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, Sao Paulo (Brazil)
2016-02-15
In this work we investigate generalized theories of gravity in the so-called configurational entropy (CE) context. We show, by means of this information-theoretical measure, that a stricter bound on the parameter of f(R, T) brane models arises from the CE. We find that these bounds are characterized by a valley region in the CE profile, where the entropy is minimal. We argue that the CE measure can play a new role and might be an important additional approach to selecting parameters in modified theories of gravitation. (orig.)
Brane World Models Need Low String Scale
Antoniadis, Ignatios; Calmet, Xavier
2011-01-01
Models with large extra dimensions offer the possibility of the Planck scale being of order the electroweak scale, thus alleviating the gauge hierarchy problem. We show that these models suffer from a breakdown of unitarity at around three quarters of the low effective Planck scale. An obvious candidate to fix the unitarity problem is string theory. We therefore argue that it is necessary for the string scale to appear below the effective Planck scale and that the first signature of such models would be string resonances. We further translate experimental bounds on the string scale into bounds on the effective Planck scale.
Sigma-model Solutions and Intersecting p-Branes Related to Lie Algebras
Grebeniuk, M. A.; Ivashchuk, V. D.
1998-01-01
A family of Majumdar-Papapetrou type solutions in sigma-model of p-brane origin is obtained for all direct sums of finite-dimensional simple Lie algebras. Several examples of p-brane dyonic configurations in D=10 (IIA) and D=11 supergravities corresponding to the Lie algebra sl(3,C) are considered.
Doubling of background solution in 5D stabilized brane world model
Smolyakov, Mikhail N
2009-01-01
We discuss a model providing two different stationary background solutions with flat and $dS_{4}$ metric on the branes under the same values of the fundamental parameters. It is shown that only an additional fine-tuning of the brane scalar field potentials can provide a separation between two background solutions.
Gravity in a stabilized brane world model in five-dimensional Brans-Dicke theory
Mikhailov, A S; Smolyakov, M N; Volobuev, I P
2008-01-01
Linearized equations of motion for gravitational and scalar fields are found and solved in a stabilized brane world model in five-dimensional Brans-Dicke theory. The physical degrees of freedom are isolated, the mass spectrum of Kaluza-Klein excitations is found and the coupling constants of these excitations to matter on the negative tension brane are calculated.
Brane-inspired Four-neutrino Models
Ioannisian, A N
1999-01-01
We propose a four-neutrino model which can reconcile the existing data coming from underground experiments in terms of neutrino oscillations, together with the hint from the LSND experiment and a possible neutrino contribution to the hot dark matter of the Universe. It applies the idea that extra compact dimensions, probed only by gravity and possibly gauge-singlet fields, can lower the fundamental scales such as the Planck, string or unification scales. Our fourth light neutrino $\
On Closed Timelike Curves and Warped Brane World Models
Directory of Open Access Journals (Sweden)
Slagter Reinoud Jan
2013-09-01
Full Text Available At first glance, it seems possible to construct in general relativity theory causality violating solutions. The most striking one is the Gott spacetime. Two cosmic strings, approaching each other with high velocity, could produce closed timelike curves. It was quickly recognized that this solution violates physical boundary conditions. The effective one particle generator becomes hyperbolic, so the center of mass is tachyonic. On a 5-dimensional warped spacetime, it seems possible to get an elliptic generator, so no obstruction is encountered and the velocity of the center of mass of the effective particle has an overlap with the Gott region. So a CTC could, in principle, be constructed. However, from the effective 4D field equations on the brane, which are influenced by the projection of the bulk Weyl tensor on the brane, it follows that no asymptotic conical space time is found, so no angle deficit as in the 4D counterpart model. This could also explain why we do not observe cosmic strings.
D-Brane Probes in the Matrix Model
Ferrari, Frank
2013-01-01
Recently, a new approach to large N gauge theories, based on a generalization of the concept of D-brane probes to any gauge field theory, was proposed. In the present note, we compute the probe action in the one matrix model with a quartic potential. This allows to illustrate several non-trivial aspects of the construction in an exactly solvable set-up. One of our main goal is to test the bare bubble approximation. The approximate free energy found in this approximation, which can be derived from a back-of-an-envelope calculation, matches the exact result for all values of the 't Hooft coupling with a surprising accuracy. Another goal is to illustrate the remarkable properties of the equivariant partial gauge-fixing procedure, which is at the heart of the formalism. For this we use a general xi-gauge to compute the brane action. The action depends on xi in a very non-trivial way, yet we show explicitly that its critical value does not and coincide with twice the free energy, as required by general consistency...
D-brane probes in the matrix model
International Nuclear Information System (INIS)
Recently, a new approach to large N gauge theories, based on a generalization of the concept of D-brane probes to any gauge field theory, was proposed. In the present note, we compute the probe action in the one matrix model with a quartic potential. This allows to illustrate several non-trivial aspects of the construction in an exactly solvable set-up. One of our main goal is to test the bare bubble approximation. The approximate free energy found in this approximation, which can be derived from a back-of-an-envelope calculation, matches the exact result for all values of the 't Hooft coupling with a surprising accuracy. Another goal is to illustrate the remarkable properties of the equivariant partial gauge-fixing procedure, which is at the heart of the formalism. For this we use a general ξ-gauge to compute the brane action. The action depends on ξ in a very non-trivial way, yet we show explicitly that its critical value does not and coincides with twice the free energy, as required by general consistency. This is made possible by a phenomenon of ghost condensation and the spontaneous breaking of the equivariant BRST symmetry
D-brane probes in the matrix model
Ferrari, Frank
2014-03-01
Recently, a new approach to large N gauge theories, based on a generalization of the concept of D-brane probes to any gauge field theory, was proposed. In the present note, we compute the probe action in the one matrix model with a quartic potential. This allows to illustrate several non-trivial aspects of the construction in an exactly solvable set-up. One of our main goal is to test the bare bubble approximation. The approximate free energy found in this approximation, which can be derived from a back-of-an-envelope calculation, matches the exact result for all values of the 't Hooft coupling with a surprising accuracy. Another goal is to illustrate the remarkable properties of the equivariant partial gauge-fixing procedure, which is at the heart of the formalism. For this we use a general ξ-gauge to compute the brane action. The action depends on ξ in a very non-trivial way, yet we show explicitly that its critical value does not and coincides with twice the free energy, as required by general consistency. This is made possible by a phenomenon of ghost condensation and the spontaneous breaking of the equivariant BRST symmetry.
On Closed Timelike Curves and Warped Brane World Models
Slagter, Reinoud Jan
2012-01-01
At first glance, it seems possible to construct in general relativity theory causality violating solutions. The most striking one is the Gott spacetime. Two cosmic strings, approaching each other with high velocity, could produce closed timelike curves. It was quickly recognized that this solution violates physical boundary conditions. The effective one particle generator becomes hyperbolic, so the center of mass is tachyonic. On a 5-dimensional warped spacetime, it seems possible to get an elliptic generator, so no obstruction is encountered and the velocity of the center of mass of the effective particle has an overlap with the Gott region. So a CTC could, in principle, be constructed. However, from the effective 4D field equations on the brane, which are influenced by the projection of the bulk Weyl tensor on the brane, it follows that no asymptotic conical space time is found, so no angle deficit as in the 4D counterpart model. This could also explain why we do not observe cosmic strings.
Supersymmetric Composite Models on Intersecting D-branes
Kitazawa, N
2004-01-01
We construct supersymmetric composite models of quarks and leptons from type IIA T^6/(Z_2 x Z_2) orientifolds with intersecting D6-branes. In case of T^6 = T^2 x T^2 x T^2 with no tilted T^2, a composite model of the supersymmetric SU(5) grand unified theory with three generations is constructed. In case of that one T^2 is tilted, a composite model with SU(3)_c x SU(2)_L x U(1)_Y gauge symmetry with three generations is constructed. These models are not realistic, but contain fewer additional exotic particles and U(1) gauge symmetries due to the introduction of the compositeness of quarks and leptons. The mu-term of Higgs fields can be naturally generated through the exponentially suppressed Yukawa interaction among "preons".
Branes in the GL(1 vertical stroke 1) WZNW-Model
Energy Technology Data Exchange (ETDEWEB)
Creutzig, T.; Schomerus, V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Quella, T. [Amsterdam Univ. (Netherlands). KdV Inst. for Mathematics
2007-08-15
We initiate a systematic study of boundary conditions in conformal field theories with target space supersymmetry. The WZNW model on GL(1 vertical stroke 1) is used as a prototypical example for which we find the complete set of maximally symmetric branes. This includes a unique brane of maximal super-dimension 2 vertical stroke 2, a 2-parameter family of branes with super-dimension 0 vertical stroke 2 and an infinite set of fully localized branes possessing a single modulus. Members of the latter family can only exist along certain lines on the bosonic base, much like fractional branes at orbifold singularities. Our results establish that all essential algebraic features of Cardy-type boundary theories carry over to the non-rational logarithmic WZNW model on GL(1 vertical stroke 1). (orig.)
Jacobi stability of the vacuum in the static spherically symmetric brane world models
Harko, T
2008-01-01
We analyze the stability of the structure equations of the vacuum in the brane world models, by using both the linear (Lyapunov) stability analysis, and the Jacobi stability analysis, the Kosambi-Cartan-Chern (KCC) theory. In the brane world models the four dimensional effective Einstein equations acquire extra terms, called dark radiation and dark pressure, respectively, which arise from the embedding of the 3-brane in the bulk. Generally, the spherically symmetric vacuum solutions of the brane gravitational field equations, have properties quite distinct as compared to the standard black hole solutions of general relativity. We close the structure equations by assuming a simple linear equation of state for the dark pressure. In this case the vacuum is Jacobi stable only for a small range of values of the proportionality constant relating the dark pressure and the dark radiation. The unstable trajectories on the brane behave chaotically, in the sense that after a finite radial distance it would be impossible...
Configurational Entropy in Brane-world Models: A New Approach to Stability
Correa, R A C
2015-01-01
In this work we investigate the entropic information on thick brane-worlds scenarios and its consequences. The brane-world entropic information is studied for the sine-Gordon model is and hence the brane-world entropic information measure is shown an accurate way for providing the most suitable values for the bulk AdS curvature. Besides, the brane-world configurational entropy is employed to demonstrate a high organisational degree in the structure of the system configuration, for large values of a parameter of the sine-Gordon model but the one related to the AdS curvature. The Gleiser and Stamatopoulos procedure is finally applied in order to achieve a precise correlation between the energy of the system and the brane-world configurational entropy.
Chiral symmetry breaking in lattice QED model with fermion brane
Shintani, E
2012-01-01
We propose a novel approach of spontaneous chiral symmetry breaking at near zero temperature in 4 dimensional QED model with 3+1 dimensional fermion brane using Hybrid Monte Carlo simulation. We consider an anisotropic QED coupling in non-compact QED action with the manifest gauge invariant interaction and fermi-velocity which is less than speed of light. This model allows for the scaling study at low temperature and strong coupling region with reduced computational cost. We compute the chiral condensate and its susceptibility with different coupling constant, velocity parameter and flavor number, and therefore obtain a compatible behavior with gap equation in broken phase. We also discuss about the comparison of Graphene model.
D-brane Solitons in Supersymmetric Sigma-Models
Gauntlett, J P; Tong, D; Townsend, P K; Gauntlett, Jerome P.; Portugues, Rubén; Tong, David; Townsend, Paul K.
2001-01-01
Massive D=4 N=2 supersymmetric sigma models typically admit domain wall (Q-kink) solutions and string (Q-lump) solutions, both preserving 1/2 supersymmetry. We exhibit a new static 1/4 supersymmetric `kink-lump' solution in which a string ends on a wall, and show that it has an effective realization as a BIon of the D=4 super DBI-action. It is also shown to have a time-dependent Q-kink-lump generalization which reduces to the Q-lump in a limit corresponding to infinite BI magnetic field. All these 1/4 supersymmetric sigma-model solitons are shown to be realized in M-theory as calibrated, or `Q-calibrated', M5-branes in an M-monopole background.
Super Lie n-algebra extensions, higher WZW models, and super p-branes with tensor multiplet fields
Fiorenza, Domenico; Schreiber, Urs
2013-01-01
We formalize higher dimensional and higher gauge WZW-type sigma-model local prequantum field theory, and discuss its rationalized/perturbative description in (super-)Lie n-algebra homotopy theory (the true home of the "FDA"-language used in the supergravity literature). We show generally how the intersection laws for such higher WZW-type sigma-model branes (open brane ending on background brane) are encoded precisely in (super-) L-infinity-extension theory and how the resulting "extended (super-)spacetimes" formalize spacetimes containing sigma model brane condensates. As an application we prove in Lie n-algebra homotopy theory that the complete super p-brane spectrum of superstring/M-theory is realized this way, including the pure sigma-model branes (the "old brane scan") but also the branes with tensor multiplet worldvolume fields, notably the D-branes and the M5-brane. For instance the degree-0 piece of the higher symmetry algebra of 11-dimensional spacetime with an M2-brane condensate turns out to be the ...
Indian Academy of Sciences (India)
Dileep P Jatkar
2003-02-01
We review proposals of brane world models which attempt to combine gauge theories with gravity at TeV scale by conﬁning the gauge theory to a three-brane embedded in higher dimensional bulk. Gravity, however, propagates in the directions transverse to the brane as well.
The structure of f(R)-brane model
Energy Technology Data Exchange (ETDEWEB)
Xu, Zeng-Guang; Yu, Hao [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China); Zhong, Yuan [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China); Universitat Autonoma de Barcelona, IFAE, Barcelona (Spain); Liu, Yu-Xiao [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China); Lanzhou University, Key Laboratory for Magnetism and Magnetic Materials of the MoE, Lanzhou (China)
2015-08-15
Recently, a family of interesting analytical brane solutions were found in f(R) gravity with f(R) = R + αR{sup 2} in Bazeia et al. (Phys Lett B 729:127 2014). In these solutions, the inner brane structure can be turned on by tuning the value of the parameter α. In this paper, we investigate how the parameter α affects the localization and the quasilocalization of the tensorial gravitons around these solutions. It is found that, in a range of α, despite the brane having an inner structure, there is no graviton resonance. However, in some other regions of the parameter space, although the brane has no internal structure, the effective potential for the graviton Kaluza-Klein (KK) modes has a singular structure, and there exist a series of graviton resonant modes. The contribution of the massive graviton KK modes to Newton's law of gravity is discussed briefly. (orig.)
The virial theorem and the dynamics of clusters of galaxies in the brane world models
Harko, T.; Cheng, K. S.
2007-01-01
A version of the virial theorem, which takes into account the effects of the non-compact extra-dimensions, is derived in the framework of the brane world models. In the braneworld scenario, the four dimensional effective Einstein equation has some extra terms, called dark radiation and dark pressure, respectively, which arise from the embedding of the 3-brane in the bulk. To derive the generalized virial theorem we use a method based on the collisionless Boltzmann equation. The dark radiation...
Fermions in five-dimensional brane world models
Smolyakov, Mikhail N.
2016-06-01
In the present paper the fermion fields, living in the background of five-dimensional warped brane world models with compact extra dimension, are thoroughly examined. The Kaluza-Klein decomposition and isolation of the physical degrees of freedom is performed for those five-dimensional fermion field Lagrangians, which admit such a decomposition to be performed in a mathematically consistent way and provide a physically reasonable four-dimensional effective theory. It is also shown that for the majority of five-dimensional fermion field Lagrangians there are no (at least rather obvious) ways to perform the Kaluza-Klein decomposition consistently. Moreover, in these cases one may expect the appearance of various pathologies in the four-dimensional effective theory. Among the cases, for which the Kaluza-Klein decomposition can be performed in a mathematically consistent way, the case, which reproduces the Standard Model by the zero Kaluza-Klein modes most closely regardless of the size of the extra dimension, is examined in detail in the background of the Randall-Sundrum model.
N=(4,4) Gauged Linear Sigma Models for Defect Five-branes
Kimura, Tetsuji
2015-01-01
We study two-dimensional ${\\cal N}=(4,4)$ gauged linear sigma model (GLSM). Its low energy effective theory is a nonlinear sigma model whose target space gives rise to a configuration of five-branes in string theory. In this article we focus on sigma models for NS5-branes, KK5-branes and an exotic $5^2_2$-brane. In particular, we carefully analyze the GLSM for an exotic $5^2_2$-brane whose background configuration is multi-valued. The exotic $5^2_2$-brane is a concrete example of nongeometric configuration in string theory. We find that the exotic feature originates from the string winding coordinate in a very clear way. In order to complete this analysis, we propose a duality transformation formula which converts an ${\\cal N}=(2,2)$ chiral superfield in F-term to a twisted chiral superfield coupled to an unconstrained complex superfield. This article is a short review based on arXiv:1304.4061 in collaboration with Shin Sasaki.
Holographic dark energy in braneworld models with moving branes and the w = −1 crossing
International Nuclear Information System (INIS)
We apply the bulk holographic dark energy in general 5D two-brane models. We extract the Friedmann equation on the physical brane and we show that in the general moving-brane case the effective 4D holographic dark energy behaves as a quintom for a large parameter-space area of a simple solution subclass. We find that wΛ was larger than −1 in the past while its present value is wΛ0≈−1.05, and the phantom bound wΛ = −1 was crossed at zp≈0.41, a result in agreement with observations. Such a behavior arises naturally, without the inclusion of special fields or potential terms, but a fine-tuning between the 4D Planck mass and the brane tension has to be imposed
Metric factorizability and equivalence of brane world models with Brans-Dicke theory
Chakraborty, Sumanta
2015-01-01
In the standard brane world models, the bulk metric ansatz is usually assumed to be factorizable in brane and bulk coordinates. However it is not self evident that it is always possible to factorize the bulk metric. Using gradient expansion scheme, which involves, expansion of bulk quantities in terms of the brane to bulk curvature ratio, as perturbative parameter, we have explicitly shown that upto second order in perturbative expansion, metric factorizability is a valid assumption. We have also argued from our result that the same should be true for all orders in the perturbation scheme. We further establish that the non-local terms present in the bulk gravitational field equation can be replaced by radion field and the effective action on the brane obtained thereof resembles Brans-Dicke theory of gravity.
Fermions in five-dimensional brane world models
Smolyakov, Mikhail N
2016-01-01
In the present paper the fermion fields, living in the background of five-dimensional warped brane world models with compact extra dimension, are thoroughly examined. The Kaluza-Klein decomposition and isolation of the physical degrees of freedom is performed for those five-dimensional fermion field Lagrangians, which admit such a decomposition to be performed in a mathematically consistent way and provide a physically reasonable four-dimensional effective theory. It is also shown that for the majority of five-dimensional fermion field Lagrangians there are no (at least rather obvious) ways to perform the Kaluza-Klein decomposition consistently. Moreover, in these cases one may expect the appearance of various pathologies in the four-dimensional effective theory. Among the cases, for which the Kaluza-Klein decomposition can be performed in a mathematically consistent way, the case, which reproduces the Standard Model by the zero Kaluza-Klein modes most closely regardless of the size of the extra dimension, is...
Simple inflationary models in Gauss-Bonnet brane-world cosmology
Okada, Nobuchika; Okada, Satomi
2016-06-01
In light of the recent Planck 2015 results for the measurement of the cosmic microwave background (CMB) anisotropy, we study simple inflationary models in the context of the Gauss-Bonnet (GB) brane-world cosmology. The brane-world cosmological effect modifies the power spectra of scalar and tensor perturbations generated by inflation and causes a dramatic change for the inflationary predictions of the spectral index (n s) and the tensor-to-scalar ratio (r) from those obtained in the standard cosmology. In particular, the predicted r values in the inflationary models favored by the Planck 2015 results are suppressed due to the GB brane-world cosmological effect, which is in sharp contrast with inflationary scenario in the Randall-Sundrum brane-world cosmology, where the r values are enhanced. Hence, these two brane-world cosmological scenarios are distinguishable. With the dramatic change of the inflationary predictions, the inflationary scenario in the GB brane-world cosmology can be tested by more precise measurements of n s and future observations of the CMB B-mode polarization.
Energy Technology Data Exchange (ETDEWEB)
Bouhmadi-Lopez, Mariam [Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Ferrera, Antonio, E-mail: mariam.bouhmadi@fisica.ist.utl.pt, E-mail: a.ferrera.pardo@gmail.com [Centro de Fisica ' Miguel A Catalan' , Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)
2008-10-15
We construct a new brane-world model composed of a bulk with a dilatonic field, plus a brane with brane tension coupled to the dilaton, cold dark matter and an induced gravity term. It is possible to show that, depending on the nature of the coupling between the brane tension and the dilaton, this model can describe the late time acceleration of the brane expansion (for the normal branch) as it moves within the bulk. The acceleration is produced together with a mimicry of the crossing of the cosmological constant line (w = -1) on the brane, although this crossing of the phantom divide is obtained without invoking any phantom matter either on the brane or in the bulk. The role of dark energy is played by the brane tension, which reaches a maximum positive value along the cosmological expansion of the brane. It is precisely at that maximum that the crossing of the phantom divide takes place. We also show that these results remain valid when the induced gravity term on the brane is switched off.
Bouhmadi-Lopez, Mariam
2008-01-01
We construct a new brane-world model composed of a bulk -with a dilatonic field-, plus a brane -with brane tension coupled to the dilaton-, cold dark matter and an induced gravity term. It is possible to show that depending on the nature of the coupling between the brane tension and the dilaton this model can describe the late-time acceleration of the brane expansion (for the normal branch) as it moves within the bulk. The acceleration is produced together with a mimicry of the crossing of the cosmological constant line (w=-1) on the brane, although this crossing of the phantom divide is obtained without invoking any phantom matter neither on the brane nor in the bulk. The role of dark energy is played by the brane tension, which reaches a maximum positive value along the cosmological expansion of the brane. It is precisely at that maximum that the crossing of the phantom divide takes place. We also show that these results remain valid when the induced gravity term on the brane is switched off.
Bulk metric of brane world models and submanifolds in 6D pseudo-Euclidian space-time
Smolyakov, Mikhail N
2010-01-01
In this short note, five-dimensional brane world models with dS_{4} metric on the branes are discussed. The explicit coordinate transformations, which show the equivalence between the bulk metric of these brane world models and the metric induced on an appropriate submanifolds in the flat six-dimensional pseudo-Euclidean space-time, are presented. The cases of the zero and non-zero cosmological constant in the bulk are discussed in detail.
On cross-section computation in the brane-world models
Dmitry, Kirpichnikov
2014-06-01
We present Mathematica7 numerical simulation of the process pp → jet + E/Tin the framework of modified Randall-Sundrum brane-world model with one infinite and n compact extra dimension. We compare the energy missing signature with the standard model background pp → jet + vbar v, which was simulated at CompHep. We show that the models with numbers of compact extra dimensions greater than 4 can be probed at the protons center-of-mass energy equal 14 TeV. We also find that testing the brane-world models at 7 TeV on the LHC appears to hopeless.
Cosmological constraints on parameters of one-brane models with extra dimension
Iofa, Mikhail Z
2009-01-01
We study some aspects of cosmologies in 5D models with one infinite extra dimension. Matter is confined to the brane, gravity extends to the bulk. Models with positive and negative tension of the brane are considered. Cosmological evolution of the 4D world is described by warped solutions of the generalized Friedmann equation. Cosmological solutions on the brane are obtained with the input of the present-time observational cosmological parameters. We estimate the age of the Universe and abundance of ${}^4 He$ produced in primordial nucleosynthesis in different models. Using these estimates we find constraints on dimensionless combinations of the 5D gravitational scale, scale of the warp factor and coupling at the 4D curvature term in the action.
Large Scale Structure Formation of normal branch in DGP brane world model
Song, Yong-Seon
2007-01-01
In this paper, we study the large scale structure formation of the normal branch in DGP model (Dvail, Gabadadze and Porrati brane world model) by applying the scaling method developed by Sawicki, Song and Hu for solving the coupled perturbed equations of motion of on-brane and off-brane. There is detectable departure of perturbed gravitational potential from LCDM even at the minimal deviation of the effective equation of state w_eff below -1. The modified perturbed gravitational potential weakens the integrated Sachs-Wolfe effect which is strengthened in the self-accelerating branch DGP model. Additionally, we discuss the validity of the scaling solution in the de Sitter limit at late times.
Regarding the Radion in Randall-Sundrum Models with Brane Curvature
Dillon, Barry M; McDonald, Kristian L
2016-01-01
In Randall-Sundrum models, one typically expects the radion to be the lightest new "gravity" state, as it is dual to a composite pseudo-Goldstone boson associated with conformal symmetry breaking in the IR. Here, we investigate the effects of localized brane curvature on the properties of the radion in Goldberger-Wise stabilized Randall-Sundrum models. We point out that both the radion mass and coupling to brane matter are sensitive to the brane curvature. Radion/Higgs kinetic mixing, via an IR-localized non-minimal coupling to the Higgs, is also investigated, in relation to the ghost-like radion that can occur for $\\mathcal{O}(10)$ values of the IR curvature (as required to significantly suppress the first Kaluza-Klein graviton mass). We also discuss a class of speculative IR localized terms involving the radion. Basic comments regarding the dual 4D theory are offered.
Regarding the radion in Randall-Sundrum models with brane curvature
Dillon, Barry M.; George, Damien P.; McDonald, Kristian L.
2016-09-01
In Randall-Sundrum models, one typically expects the radion to be the lightest new "gravity" state, as it is dual to a composite pseudo-Goldstone boson associated with conformal symmetry breaking in the IR. Here, we investigate the effects of localized brane curvature on the properties of the radion in Goldberger-Wise stabilized Randall-Sundrum models. We point out that both the radion mass and coupling to brane matter are sensitive to the brane curvature. Radion/Higgs kinetic mixing, via an IR-localized nonminimal coupling to the Higgs, is also investigated, in relation to the ghostlike radion that can occur for O (10 ) values of the IR curvature (as required to significantly suppress the first Kaluza-Klein graviton mass). We also discuss a class of IR-localized terms involving the radion. Basic comments regarding the dual four-dimensional theory are offered.
Higgs-radion mixing in stabilized brane world models
Boos, Edward E; Perfilov, Maxim A; Smolyakov, Mikhail N; Volobuev, Igor P
2015-01-01
We consider a quartic interaction of the Higgs and Goldberger-Wise fields, which connects the mechanism of the extra dimension size stabilization with spontaneous symmetry breaking on our brane and gives rise to a coupling of the Higgs field to the radion and its KK tower. We estimate a possible influence of this coupling on the Higgs-radion mixing and study its experimental consequences.
Simple inflationary models in Gauss-Bonnet brane-world cosmology
Okada, Nobuchika
2014-01-01
In light of the recent measurements of the CMB anisotropy by the WMAP and Planck satellite experiments and the observation of CMB $B$-mode polarization announced by the BICEP2 collaboration, we study simple inflationary models in the context of the Gauss-Bonnet brane-world cosmology. The brane-world cosmological effect modifies the power spectra of scalar and tensor perturbations generated by inflation and causes a dramatic change for the inflationary predictions of the spectral index ($n_s$) and the tensor-to-scalar ratio ($r$) from those obtained in the standard cosmology. In particular, the power spectrum of tensor perturbation is suppressed due to the Gauss-Bonnet brane-world cosmological effect, which is in sharp contrast with inflationary scenario in the Randall-Sundrum brane-world cosmology where the power spectrum is enhanced. Hence, these two brane-world cosmological scenarios are distinguishable. With the dramatic change of the inflationary predictions, the inflationary scenario in the Gauss-Bonnet ...
On cross-section computation in the brane-world models
Kirpichnikov, D V
2013-01-01
We present Mathematica7 numerical simulation of the process $pp\\rightarrow\\mbox{jet}+E_{T}^{miss}$ in the framework of modified Randall-Sundrum brane-world model with one infinite and $n$ compact extra dimension. We compare the energy missing signature with the standard model background $pp\\rightarrow \\mbox{jet}+\
"Mass Inflation" With Lightlike Branes
Guendelman, Eduardo; Nissimov, Emil; Pacheva, Svetlana
2007-01-01
We discuss properties of a new class of p-brane models, describing intrinsically lightlike branes for any world-volume dimension, in various gravitational backgrounds of interest in the context of black hole physics. One of the characteristic features of these lightlike p-branes is that the brane tension appears as an additional nontrivial dynamical world-volume degree of freedom. Codimension one lightlike brane dynamics requires that the bulk space possesses an event horizon which is automatically occupied by the lightlike brane while its tension evolves exponentially with time. The latter phenomenon is an analog of the well known "mass inflation" effect in black holes.
A Matrix Model for the Null-Brane
Robbins, Daniel; Sethi, Savdeep
2005-01-01
The null-brane background is a simple smooth 1/2 BPS solution of string theory. By tuning a parameter, this background develops a big crunch/big bang type singularity. We construct the DLCQ description of this space-time in terms of a Yang-Mills theory on a time-dependent space-time. Our dual Matrix description provides a non-perturbative framework in which the fate of both (null) time, and the string S-matrix can be studied.
Coincidence of the Universe Description Stemming from D-branes Theory and ENU Model
Sima, Jozef; Sukenik, Miroslav
2001-01-01
The contribution provides a comparison of consequences stemming from D-brane theories and Expansive Nondecelerative Universe model, and calls attention to coincidence of the results arising from the mentioned approaches to a description of the Universe. It follows from the comparison that the effects of quantum gravitation should appear at the energy near to 2 TeV.
Discussing string extensions of the Standard Model in D brane world
Di Vecchia, P
2009-01-01
In this talk we will describe the problems that one encounters when one tries to connect string theory with particle phenomenology. Then, in order to have chiral matter describing quarks and leptons, we introduce the magnetized D branes. Finally, as an explicit example of a string extension of the Standard Model, we will describe the one constructed by Ibanez, Marchesano and Rabadan.
Submanifolds in space-time with unphysical extra dimensions, cosmology and warped brane world models
Smolyakov, Mikhail N
2008-01-01
The explicit coordinate transformations which show the equivalence between a four-dimensional spatially flat cosmology and an appropriate submanifold in the flat five-dimensional Minkowski space-time are presented. Analogous procedure is made for the case of five-dimensional warped brane world models. Several examples are presented.
Discussing string extensions of the Standard Model in D brane world
Energy Technology Data Exchange (ETDEWEB)
Di Vecchia, Paolo [Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark); NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)
2009-01-15
In this talk we will describe the problems that one encounters when one tries to connect string theory with particle phenomenology. Then, in order to have chiral matter describing quarks and leptons, we introduce the magnetized D branes. Finally, as an explicit example of a string extension of the Standard Model, we will describe the one constructed by Ibanez, Marchesano and Rabadan.
Energy Technology Data Exchange (ETDEWEB)
Bergshoeff, Eric A., E-mail: E.A.Bergshoeff@rug.nl [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Marrani, Alessio, E-mail: Alessio.Marrani@cern.ch [Physics Department, Theory Unit, CERN, CH-1211, Geneva 23 (Switzerland); Riccioni, Fabio, E-mail: Fabio.Riccioni@roma1.infn.it [INFN Sezione di Roma, Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185 Roma (Italy)
2012-08-01
We complete the classification of half-supersymmetric branes in toroidally compactified IIA/IIB string theory in terms of representations of the T-duality group. As a by-product we derive a last wrapping rule for the space-filling branes. We find examples of T-duality representations of branes in lower dimensions, suggested by supergravity, of which none of the component branes follow from the reduction of any brane in ten-dimensional IIA/IIB string theory. We discuss the constraints on the charges of half-supersymmetric branes, determining the corresponding T-duality and U-duality orbits.
Phantom-like behaviour in a brane-world model with curvature effects
Bouhmadi-Lopez, Mariam
2008-01-01
Recent observational evidence seems to allow the possibility that our universe may currently be under a dark energy effect of a phantom nature. A suitable effective phantom fluid behaviour can emerge in brane cosmology; In particular, within the normal non self-accelerating DGP branch, without any exotic matter and due to curvature effects from induced gravity. The phantom-like behaviour is based in defining an effective energy density that grows as the brane expands. This effective description breaks down at some point in the past when the effective energy density becomes negative and the effective equation of state parameter blows up. In this paper we investigate if the phantom-like regime can be enlarged by the inclusion of a Gauss-Bonnet (GB) term into the bulk. The motivation is that such a GB component would model additional curvature effects on the brane setting. More precisely, our aim is to determine if the GB term, dominating and modifying the early behaviour of the brane universe, may eventually ex...
Gravitational resonances on f(R)-brane
Energy Technology Data Exchange (ETDEWEB)
Yu, Hao; Gu, Bao-Min [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China); Zhong, Yuan [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China); Universitat Autonoma de Barcelona, IFAE, Bellaterra, Barcelona (Spain); Liu, Yu-Xiao [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China); Lanzhou University, Key Laboratory for Magnetism and Magnetic Materials of the MoE, Lanzhou (China)
2016-04-15
In this paper, we investigate various f(R)-brane models and compare their gravitational resonance structures with the corresponding general relativity (GR)-branes. Starting from some known GR-brane solutions, we derive thick f(R)-brane solutions such that the metric, scalar field, and scalar potential coincide with those of the corresponding GR-branes.We find that for the branes generated by a single or several canonical scalar fields, there is no obvious distinction between the GR-branes and the corresponding f(R)-branes in terms of gravitational resonance structure. Then we discuss the branes generated by a K-field. In this case, there could exist huge differences between GR-branes and f(R)-branes. (orig.)
A non-minimally coupled quintom dark energy model on the warped DGP brane
Energy Technology Data Exchange (ETDEWEB)
Nozari, K; Azizi, T [Department of Physics, Faculty of Basic Sciences, University of Mazandaran, PO Box 47416-95447, Babolsar (Iran, Islamic Republic of); Setare, M R [Department of Science, University of Kurdistan, Pasdaran Ave, Sanandaj (Iran, Islamic Republic of); Behrouz, N [Department of Physics, Payam-e Nour University, PO Box 919, Mashad (Iran, Islamic Republic of)], E-mail: knozari@umz.ac.ir, E-mail: rezakord@ipm.ir, E-mail: t.azizi@umz.ac.ir
2009-08-15
We construct a quintom dark energy model with two non-minimally coupled scalar fields, one quintessence and the other phantom field, confined to the warped Dvali-Gabadadze-Porrati (DGP) brane. We show that this model accounts for crossing of the phantom divide line in appropriate subspaces of the model parameter space. This crossing occurs for both normal and self-accelerating branches of this DGP-inspired setup.
Randall-Sundrum limit of f(R) brane-world models
Balcerzak, Adam
2011-01-01
By setting some special boundary conditions in the variational principle we obtain junction conditions for the five-dimensional $f(R)$ gravity which in the Einstein limit $f(R)\\rightarrow R$ transform into the standard Randall-Sundrum junction conditions. We apply these junction conditions to a particular model of a Friedmann universe on the brane and show explicitly that the limit gives the standard Randall-Sundrum model Friedmann equation.
Geodesics and Newton's Law in Brane Backgrounds
Mück, W; Volovich, I V
2000-01-01
In brane world models our universe is considered as a brane imbedded into ahigher dimensional space. We discuss the behaviour of geodesics in theRandall-Sundrum background and point out that free massive particles cannotmove along the brane only. The brane is repulsive, and matter will be expelledfrom the brane into the extra dimension. This is rather undesirable, and hencewe study an alternative model with a non-compact extra dimension, but with anattractive brane embedded into the higher dimensional space. We study thelinearized gravity equations and show that Newton's gravitational law is validon the brane also in the alternative background.
Higgs-gluon coupling in warped extra dimensional models with brane kinetic terms
Dey, Ujjal Kumar; Ray, Tirtha Sankar
2016-01-01
Warped models with the Higgs confined to the weak brane and the gauge and matter fields accessing the AdS5 bulk provide a viable setting to address the gauge hierarchy problem. Brane kinetic terms for the bulk fields are known to ease some of the tensions of these models with precision electroweak observables and flavor constraints. We study the loop-driven Higgs coupling to the gluons that are relevant to the Higgs program at the LHC, in this scenario. We demonstrate a partial cancellation in the contribution of the fermionic Kaluza-Klein (KK) towers within such framework relatively independent of the 5D parameters. The entire dependence of this coupling on the new physics arises from the mixing between the Standard Model states and the KK excitations. We find that the present precision in measurement of these couplings can lead to a constraint on the KK scale up to 1.2 TeV at 95% confidence level.
Simple brane-world inflationary models in light of BICEP2
Okada, Nobuchika
2014-01-01
Motivated by the recent CMB $B$-mode observation announced by the BICEP2 collaboration, we study simple inflationary models in the Randall-Sundrum brane-world cosmology. Brane-world cosmological effects alter the inflationary predictions of the spectral index ($n_s$) and the tensor-to-scalar ratio ($r$) from those obtained in the standard cosmology. In particular, the tensor-to-scalar ratio is enhanced in the presence of the 5th dimension, and simple inflationary models which predict small $r$ values in the standard cosmology can yield $r$ values being compatible with the BICEP2 result, $r=0.2^{+0.07}_{-0.05}$. Confirmation of the BICEP2 result and more precise measurements of $n_s$ and $r$ in the near future allow us to constrain the 5-dimensional Planck mass ($M_5$) of the brane-world scenario. We also discuss the post inflationary scenario, namely, reheating of the universe through inflaton decay to the Standard Model particles. When we require the renormalizability of the inflationary models, the inflaton...
Global D-brane models with stabilised moduli and light axions
Cicoli, Michele
2012-01-01
We review recent attempts to try to combine global issues of string compactifications, like moduli stabilisation, with local issues, like semi-realistic D-brane constructions. We list the main problems encountered, and outline a possible solution which allows globally consistent embeddings of chiral models. We also argue that this stabilisation mechanism leads to an axiverse. We finally illustrate our general claims in a concrete example where the Calabi-Yau manifold is explicitly described by toric geometry.
Shortcuts for graviton propagation in a six-dimensional brane world model
Energy Technology Data Exchange (ETDEWEB)
Abdalla, Elcio; Casali, Adenauer; Cuadros-Melgar, Bertha E-mail: bertha@fma.if.usp.br
2002-11-11
We consider a six-dimensional brane world model with asymmetric warp factors for time and both extra spatial coordinates, y and z. We derive the set of differential equations governing the shortest graviton path and numerically solve it for AdS-Schwarzschild and AdS-Reissner-Nordstroem bulks. In both cases we derive a set of conditions for the existence of shortcuts in bulks with shielded singularities and show some examples of shortcuts obtained under these conditions. Consequences are discussed.
Hierarchy problem and the cosmological constant in a five-dimensional Brans-Dicke brane world model
Smolyakov, Mikhail N
2010-01-01
We discuss a new solution, admitting the existence of dS_{4} branes, in five-dimensional Brans-Dicke theory. It is shown that, due to a special form of a bulk scalar field potential, for certain values of the model parameters the effective cosmological constant can be made small on the brane, where the hierarchy problem of gravitational interaction is solved. We also discuss new stabilization mechanism which is based on the use of auxiliary fields.
Smolyakov, Mikhail N
2015-01-01
In the present paper we discuss some problems which arise, when the matter, gauge and Higgs fields are allowed to propagate in the bulk of five-dimensional brane world models with compact extra dimension and their zero Kaluza-Klein modes are supposed to exactly reproduce the Standard Model fields and their interactions.
Micro-orbits in a many-branes model and deviations from $1/r^2$ Newton's law
Donini, A
2016-01-01
We consider a 5-dimensional model with geometry ${\\cal M} = {\\cal M}_4 \\times {\\cal S}_1$, with compactification radius $R$. The Standard Model particles are localized onto a brane located at y=0, with identical branes localized at different points in the extra dimension. Objects located on our brane can orbit around objects located on a brane at a distance $d=y/R$, with an orbit and a period significantly different from the standard Newtonian ones. We study the kinematical properties of the orbits, finding that it is possible to distinguish one motion from the other in a large region of the initial conditions parameter space. This is a warm-up to study if a SM-like mass distribution on a distant brane may represent a possible dark matter candidate. After using the same technique to the study of orbits of objects lying on the same brane ($d=0$), we apply this method to detect generic deviations from the inverse-square Newton's law. We propose a possible experimental setup to look for departures from Newtonian...
Sahni, Varun
2016-07-01
The Phantom brane is based on the normal branch of the DGP braneworld. It possesses a phantom-like equation of state at late times, but no big-rip future singularity. In this braneworld, the cosmological constant is dynamically screened at late times. Consequently it provides a good fit to SDSS DR11 measurements of H(z) at high redshifts. We obtain a closed system of equations for scalar perturbations on the brane. Perturbations of radiation, matter and the Weyl fluid are self-consistently evolved until the present epoch. We find that the late time growth of density perturbations on the brane proceeds at a faster rate than in ΛCDM. Additionally, the gravitational potentials φ, Ψ evolve differently on the brane than in ΛCDM, for which φ = Ψ. On the Brane, by contrast, the ratio φ/Ψ exceeds unity during the late matter dominated epoch (z ≤ 50). These features emerge as smoking gun tests of phantom brane cosmology and allow predictions of this scenario to be tested against observations of galaxy clustering and large scale structure. The phantom brane also displays a pole in its equation of state, which provides a key test of this dark energy model.
Dynamical Generation of Yukawa Couplings in Intersecting D-brane Models
Kitazawa, N
2004-01-01
We propose a scenario to obtain non-trivial Yukawa coupling matrices for the quark-lepton mass generation in supersymmetric intersecting D-brane models in type IIA T^6/Z_2 x Z_2 orientifold. As an example, an explicit model is constructed in which all the four generations of quarks and leptons and two pairs of massless Higgs fields are composite. In this model non-trivial Yukawa interactions are obtained by the interplay between the string-level higher dimensional interactions among "preons" and the dynamics of the confinement of "preons".
Bazeia, D
2004-01-01
We investigate a system described by two real scalar fields coupled with gravity in (4, 1) dimensions in warped spacetime involving one extra dimension. The results show that the parameter which controls the way the two scalar fields interact induces the appearence of thick brane which engenders internal structure, driving the energy density to localize inside the brane in a very specific way.
Bergshoeff, E. A.; Lozano, Y.; Ortín, Tomas
1997-01-01
Published in: Nucl. Phys. B 518 (1998) 363-423 citations recorded in [Science Citation Index] Abstract: We investigate the effective worldvolume theories of branes in a background given by (the bosonic sector of) 10-dimensional massive IIA supergravity (``massive branes'') and their M-theoretic orig
Viña, Andrés
2015-01-01
Given a Calabi-Yau manifold $X$ acted by a group $G$ and considering the $B$-branes on $X$ as objects in the derived category of coherent sheaves, we give a definition of equivariant branes, which generalizes the concept of equivariant sheaves. We also propose a definition of equivariant charge of an equivariant brane. The spaces of strings joining the branes ${\\mathcal F}$ and ${\\mathcal G}$, are the groups $Ext^i({\\mathcal F},\\,{\\mathcal G})$. We prove that the spaces of strings between two $G$-equivariant branes support representations of $G$. Thus, these spaces can be decomposed in direct sum of invariant spaces for the $G$-action. We show some particular decompositions, when $X$ is a toric variety and when $X$ is a flag manifold of a semisimple Lie group.
Brane collisions in anti-de Sitter space
Neronov, Andrey
2001-01-01
From the requirement of continuous matching of bulk metric around the point of brane collision we derive a conservation law for collisions of p-branes in (p+2)-dimensional space-time. This conservation law relates energy densities on the branes before and after the collision. Using this conservation law we are able to calculate the amount of matter produced in the collision of orbifold-fixed brane with a bulk brane in the ``ekpyrotic/pyrotechnic type'' models of brane cosmologies.
Gmeiner, Florian
2009-01-01
We perform a complete analysis of one-loop threshold corrections to the gauge couplings of fractional D6-branes. This includes besides SU(N) also symplectic, orthogonal and massless Abelian gauge factors and the full computation of contributions from discrete and continuous Wilson lines and brane displacements. Two classes of globally consistent supersymmetric compactifications with Standard Model spectra on T6/Z6 and T6/Z6' are presented in detail with the latter exhibiting the potential of supersymmetry breaking via a hidden sector gaugino condensate. The T6/Z6' Standard Models are completely classified, and it turns out that out of 768 distinct D6-brane configurations only 16 different sets of massless spectra and ten distinct values of gauge couplings at one-loop arise. The gauge threshold corrections enhance the diversity to 196 nonequivalent models.
Information content in $F(R)$ brane models with non-constant curvature
Correa, R A C; Dutra, A de Souza; da Rocha, Roldao; Menezes, R
2015-01-01
In this work we investigate the entropic information-measure in the context of braneworlds with non-constant curvature. The braneworld entropic information is studied for gravity modified by the squared of the Ricci scalar, besides the usual Einstein-Hilbert term. We showed that the minimum value of the brane configurational entropy provides a stricter bound on the parameter that is responsible for the $F(R)$ model to differ from the Einstein-Hilbert standard one. Our results are moreover consistent to a negative bulk cosmological constant.
D-branes and matrix factorisations in supersymmetric coset models
Behr, Nicolas
2010-01-01
Matrix factorisations describe B-type boundary conditions in N=2 supersymmetric Landau-Ginzburg models. At the infrared fixed point, they correspond to superconformal boundary states. We investigate the relation between boundary states and matrix factorisations in the Grassmannian Kazama-Suzuki coset models. For the first non-minimal series, i.e. for the models of type SU(3)_k/U(2), we identify matrix factorisations for a subset of the maximally symmetric boundary states. This set provides a basis for the RR charge lattice, and can be used to generate (presumably all) other boundary states by tachyon condensation.
D7-brane dynamics and thermalization in the Kuperstein-Sonnenschein model
Kaviani, Dariush
2016-01-01
We study the temperature of rotating probe D7-branes, dual to the temperature of flavored quarks, in the Kuperstein--Sonnenschein holographic model including the effects of spontaneous breakdown of the conformal and chiral flavor symmetry. The model embeds probe D7-branes into the Klebanov-Witten gravity dual of conformal gauge theory, with the embedding parameter, given by the minimal radial extension of the probe, setting the IR scale of conformal and chiral flavor symmetry breakdown. We show that when the minimal extension is positive definite and additional spin is turned on, the induced world volume metrics on the probe admit thermal horizons and Hawking temperatures despite the absence of black holes in the bulk. We find the scale and behavior of the temperature in flavored quarks are determined notably by the IR scale of symmetry breaking, and by the strength and sort of external fields. We also derive the energy--stress tensor of the rotating probe and study its backreaction and energy dissipation. We...
TeV-scale supersymmetric standard model and brane world
Energy Technology Data Exchange (ETDEWEB)
Kakushadze, Zurab E-mail: zurab@string.harvard.edu
1999-07-12
Recently we proposed a TeV-scale Supersymmetric Standard Model in which the gauge coupling unification is as precise (at one loop) as in the MSSM, and occurs in the TeV range. One of the key ingredients of this model is the presence of new states neutral under SU(3){sub c}xSU(2){sub w} but charged under U(1){sub Y} whose mass scale is around that of the electroweak Higgs doublets. In this paper we show that the introduction of these states allows us to gauge novel anomaly free discrete (as well as continuous) symmetries (similar to 'lepton' and 'baryon' numbers) which suppress dangerous higher dimensional operators and stabilize the proton. Furthermore, the mass hierarchy between the up and down quarks (e.g. t versus b) can be explained without appealing to large tan {beta}, and the {mu}-term for the electroweak Higgs doublets (as well as for the new states) can be generated. We also discuss various phenomenological implications of our model which lead to predictions testable in the present or near future collider experiments. In particular, we point out that signatures of scenarios with high versus low unification (string) scale might be rather different. This suggests the possibility that the collider experiments may distinguish between these scenarios even without a direct production of heavy Kaluza-Klein or string states.
D-Branes at Singularities A Bottom-Up Approach to the String Embedding of the Standard Model
Aldazabal, G; Quevedo, Fernando; Uranga, Angel M
2000-01-01
We propose a bottom-up approach to the building of particle physics models from string theory. Our building blocks are Type II D-branes which we combine appropriately to reproduce desirable features of a particle theory model: 1) Chirality ; 2) Standard Model group ; 3) N=1 or N=0 supersymmetry ; 4) Three quark-lepton generations. We start such a program by studying configurations of D=10, Type IIB D3-branes located at singularities. We study in detail the case of Z_N, N=1,0 supersymmetric orbifold singularities leading to the SM group or some left-right symmetricextension. In general, tadpole cancellation conditions require the presence of additional branes, e.g. D7-branes. For the N=1 supersymmetric case the unique twist leading to three quark-lepton generations is Z_3, predicting $\\sin^2\\theta_W=3/14=0.21$. The models obtained are the simplest semirealistic string models ever built. In the non-supersymmetric case there is a three-generation model for each Z_N, N>4, but the Weinberg angle is in general too ...
Randall-Sundrum brane model with 7D anti-de Sitter space
Ruoyu, Bao; 10.1103/PhysRevLett.95.261601
2005-01-01
In the same sense that 5D anti-de Sitter space (AdS/sub 5/) warped geometries arise naturally from type IIB string theory with stacks of D3 branes, AdS/sub 7/ warped geometries arise naturally from M theory with stacks of M5 branes. We compactify two spatial dimensions of AdS /sub 7/ to get AdS/sub 5/?igma/sup 2factor as appears in the AdS/sub 5/. We analyze the 5D spectrum in detail for the case of a bulk scalar or a graviton in AdS/sub 5/?/sup 2/, in a setup which mimics the first Randall-Sundrum model. The results display novel features which might be observed in experiments at the CERN Large Hadron Collider. For example, we obtain TeV scale string winding states without lowering the string scale. This is due to the double warping which is a generic feature of winding states along compactified AdS directions. Experimental verification of these signatures of AdS/sub 7/ could be interpreted as direct evidence for M theory.
A Note on Dimer Models and D-brane Gauge Theories
Agarwal, Prarit; Sarkar, Tapobrata
2008-01-01
The connection between quiver gauge theories and dimer models has been well studied. It is known that the matter fields of the quiver gauge theories can be represented using the perfect matchings of the dimer model. We conjecture that the perfect matchings give information about the charge matrix of the quiver gauge theory. Further, we perform explicit computations on some aspects of partial resolutions of toric singularities using dimer models. We analyse these with graph theory techniques, using the perfect matchings of orbifolds of the form $\\BC^3/\\Gamma$, where the orbifolding group $\\Gamma$ may be noncyclic. Using these, we study the construction of the superpotential of gauge theories living on D-branes which probe these singularities, including the case where one or more adjoint fields are present upon partial resolution. Applying a combination of open and closed string techniques to dimer models, we also study some aspects of their symmetries.
750 GeV diphoton excesses in a realistic D-brane model
Li, Tianjun; Maxin, James A.; Mayes, Van E.; Nanopoulos, Dimitri V.
2016-07-01
We study the diphoton excesses near 750 GeV recently reported by the ATLAS and CMS collaborations within the context of a phenomenologically interesting intersecting/magnetized D-brane model on a toroidal orientifold. It is shown that the model contains a Standard Model singlet scalar as well as vector-like quarks and leptons. In addition, it is shown that the singlet scalar has Yukawa couplings with vector-like quarks and leptons such that it may be produced in proton-proton collisions via gluon fusion as well as decay to diphotons through loops involving the vector-like quarks. Moreover, the required vector-like quarks and leptons may appear in complete S U (5 ) multiplets so that gauge coupling unification may be maintained. Finally, it is shown that the diphoton signal may be accommodated within the model.
Vacuum solutions of the gravitational field equations in the brane world model
Mak, MK; Harko, TC
2004-01-01
We consider some classes of solutions of the static, spherically symmetric gravitational field equations in the vacuum in the brane world scenario, in which our Universe is a three-brane embedded in a higher dimensional space-time. The vacuum field equations on the brane are reduced to a system of two ordinary differential equations, which describe all the geometric properties of the vacuum as functions of the dark pressure and dark radiation terms (the projections of the Weyl curvature of th...
The $750$ GeV Diphoton Excesses in a Realistic D-brane Model
Li, Tianjun; Mayes, Van E; Nanopoulos, Dimitri V
2016-01-01
We study the diphoton excesses near $750$ GeV recently reported by the ATLAS and CMS collaborations within the context of a phenomenologically interesting intersecting/magnetized D-brane model on a toroidal orientifold. It is shown that the model contains a SM singlet scalar as well as vector-like quarks and leptons. In addition, it is shown that the singlet scalar has Yukawa couplings with vector-like quarks and leptons such that it may be produced in proton-proton collisions via gluon fusion as well as decay to diphotons through loops involving the vector-like quarks. Moreover, the required vector-like quarks and leptons may appear in complete $SU(5)$ multiplets so that gauge coupling unification may be maintained. Finally, it is shown that the diphoton signal may be explained within the model.
Madjumdar-Papapetrou Type Solutions in Sigma-model and Intersecting p-branes
Ivashchuk, V D
1999-01-01
The block-orthogonal generalization of the Madjumdar-Papapetrou type solutions for the sigma-model studied earlier in \\cite{IM4}-\\cite{IMC} are obtained and corresponding solutions with p-branes are considered. The existence of solutions and the number of independent harmonic functions is defined by the matrix of scalar products of vectors $U^s$, governing the sigma-model target space metric. (For orthogonal $U^s$, when target space is symmetric homogeneous space, the solutions coincide with those from finite dimensional Lie algebras and hyperbolic (Kac-Moody) algebras are singled out and investigated. The affine Cartan matrices do not arise in the scheme under consideration. Some examples of solutions and intersection rules for D=11 supergravity, related D=12 theory and extending them $B_D$-models are considered. For special multicenter solutions the indicators of horizon and curvature singularity are introduced.
Realistic D-Brane Models on Warped Throats: Fluxes, Hierarchies and Moduli Stabilization
Cascales, J F G; Quevedo, Fernando; Uranga, Angel M
2004-01-01
We describe the construction of string theory models with semirealistic spectrum in a sector of (anti) D3-branes located at an orbifold singularity at the bottom of a highly warped throat geometry, which is a generalisation of the Klebanov-Strassler deformed conifold. These models realise the Randall-Sundrum proposal to naturally generate the Planck/electroweak hierarchy in a concrete string theory embedding, and yielding interesting chiral open string spectra. We describe examples with Standard Model gauge group (or left-right symmetric extensions) and three families of SM fermions, with correct quantum numbers including hypercharge. The dilaton and complex structure moduli of the geometry are stabilised by the 3-form fluxes required to build the throat. We describe diverse issues concerning the stabilisation of geometric Kahler moduli, like blow-up modes of the orbifold singularities, via D term potentials and gauge theory non-perturbative effects, like gaugino condensation. This local geometry, once embedd...
Feng, Sheng-Fei; Huang, Yong-Chang; Liu, Xin; Zhao, Ying-Jie
2015-01-01
A generalization from the usual $5$-dimensional two-brane Randall-Sundrum (RS) model to a $6$-dimensional multi-brane RS model is presented. The extra dimensions are extended from one to two; correspondingly the single-variable warp function is generalized to be a double-variable function, to represent the two extra dimensions. In the analysis of the Einstein equation we have two remarkable discoveries. One is that, when branes are absent, the cosmological parameter distributed in the two extra dimensions acts as a function describing a family of circles. These circles are not artificially added ones but stem from the equations of motion, while their radii are inversely proportional to the square root of the cosmological parameter. The other discovery is that, on any circle, there symmetrically distribute four branes. Their tensions, $V_1 \\sim V_4$, satisfy a particular relationship $V_1=V_3=-V_2=-V_4=3M^4$, where $M$ is the $6$-dimensional fundamental scale of the RS model.
Dynamical Generation of mu-terms and Yukawa Couplings in Intersecting D-brane Models
Kitazawa, N
2004-01-01
We construct a supersymmetric composite model from type IIA T^6/(Z_2 x Z_2) orientifolds with intersecting D6-branes. All the three generations of quarks and leptons are naturally emerged as composite fields at low energies. Two pairs of light electroweak Higgs doublets can be obtained with realistic values of mu-terms. The hierarchical Yukawa couplings for the quark-lepton mass can be generated by the interplay between the string-level higher dimensional interactions among "preons" and the dynamics of the confinement of "preons". The model is not perfectly realistic in some points: some exotic particles, one additional U(1) gauge symmetry, no explicit mechanism for supersymmetry breaking, and so on.
On Symmetries of Target Space for $\\sigma$-model of p-brane Origin
Ivashchuk, V D
1998-01-01
The target space M for the sigma-model appearing in theories with p-branes is considered. It is proved that M is a homogeneous space G/H. It is symmetric if and only if the U-vectors governing the sigma-model metric are either coinciding or mutually orthogonal. For nonzero noncoinciding U-vectors the Killing equations are solved. Using a block-orthogonal decomposition of the set of the U-vectors it is shown that under rather general assumptions the algebra of Killing vectors is a direct sum of several copies of sl(2,R) algebras (corresponding to 1-vector blocks), several solvable Lie algebras (corresponding to multivector blocks) and the Killing algebra of a flat space. The target space manifold is decomposed in a product of R^m, several 2-dimensional spaces of constant curvature (e.g. Lobachevsky space, part of de Sitter space) and several solvable Lie group manifolds.
Cosmology from quantum potential in a system of oscillating branes
Sepehri, Alireza
2015-01-01
Recently, some authors proposed a new mechanism which gets rid of the big-bang singularity and shows that the age of the universe is infinite. In this paper, we will confirm their results and predict that the universe may expand and contract many times in a system of oscillating branes. In this model, first, N fundamental strings transit to N M0-anti-M0-branes. Then, M0-branes join to each other and build an M8-anti-M8 system. This system is unstable, broken and two anti-M4-branes, a compactified M4-brane, an M3-brane in additional to one M0-brane are produced. The M3-brane wraps around the compactified M4-brane and both of them oscillate between two anti-M4-branes. Our universe is located on the M3-brane and interacts with other branes by exchanging the M0-brane and some scalars in transverse directions. By wrapping of M3-brane, universe contracts and generalized uncertainty principle or GUP emerges. By oscillating the compactified M4-M3-brane and approaching to one of anti-M4-branes, one end of M3-brane glu...
Rigour and Rigidity: Systematics on particle physics D6-brane models on Z(2)xZ(6)
Ecker, Jill; Staessens, Wieland
2014-01-01
We launch a systematic search for phenomenologically appealing string vacua with intersecting D-branes on the promising T6/Z(2)xZ(6)xOR orientifold with discrete torsion. The number of independent background lattices is reduced from six to two by new symmetries. The occurrence of USp(2N) and SO(2N) versus U(N) gauge groups is classified as well as D-branes without matter in the adjoint and/or symmetric representation. Supersymmetric fractional D6-branes allowing for RR tadpole cancellation are fully classified in terms of all possible values of the one complex structure modulus inherited from the underlying six-torus. We then systematically investigate the conditions for three particle generations at pairwise intersections of two D6-branes. Global SU(5) GUT models on T6/Z(2)xZ(6)xOR are excluded by demanding three generations and no exotic matter in the 15 representation. Two prototypes of global Pati-Salam models with a mild amount of vector-like exotic matter are found.
A Study of Structure Formation and Reheating in the D3/D7 Brane Inflation Model
Brandenberger, Robert H; Davis, Anne-Christine
2008-01-01
We study the spectrum of cosmological fluctuations in the D3/D7 brane inflationary universe with particular attention to the parametric excitation of entropy modes during the reheating stage. The same tachyonic instability which renders reheating in this model very rapid leads to an exponential growth of entropy fluctuations during the preheating stage which in turn induces a large contribution to the large-scale curvature fluctuations. We take into account the effects of long wavelength quantum fluctuations in the matter fields. As part of this work, we perform an analytical analysis of the reheating process. We find that the initial stage of preheating proceeds by the tachyonic instability channel. An upper bound on the time it takes for the energy initially stored in the inflaton field to convert into fluctuations is obtained by neglecting the local fluctuations produced during the period of tachyonic decay and analyzing the decay of the residual homogeneous field oscillations, which proceeds by parametric...
Directory of Open Access Journals (Sweden)
Maartens Roy
2004-01-01
Full Text Available The observable universe could be a 1+3-surface (the "brane" embedded in a 1+3+$d$-dimensional spacetime (the "bulk", with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk. At least one of the $d$ extra spatial dimensions could be very large relative to the Planck scale, which lowers the fundamental gravity scale, possibly even down to the electroweak ($sim$TeV level. This revolutionary picture arises in the framework of recent developments in M theory. The 1+10-dimensional M theory encompasses the known 1+9-dimensional superstring theories, and is widely considered to be a promising potential route to quantum gravity. General relativity cannot describe gravity at high enough energies and must be replaced by a quantum gravity theory, picking up significant corrections as the fundamental energy scale is approached. At low energies, gravity is localized at the brane and general relativity is recovered, but at high energies gravity "leaks" into the bulk, behaving in a truly higher-dimensional way. This introduces significant changes to gravitational dynamics and perturbations, with interesting and potentially testable implications for high-energy astrophysics, black holes and cosmology. Brane-world models offer a phenomenological way to test some of the novel predictions and corrections to general relativity that are implied by M theory. This review discusses the geometry, dynamics and perturbations of simple brane-world models for cosmology and astrophysics, mainly focusing on warped 5-dimensional brane-worlds based on the Randall-Sundrum models.
Budhwani, Karim Ismail
The tremendous quality of life impact notwithstanding, cardiovascular diseases and Cancer add up to over US$ 700bn each year in financial costs alone. Aging and population growth are expected to further expand the problem space while drug research and development remain expensive. However, preclinical costs can be substantially mitigated by substituting animal models with in vitro devices that accurately model human cardiovascular transport. Here we present a novel physiologically relevant lab-on-a-brane that simulates in vivo pressure, flow, strain, and shear waveforms associated with normal and pathological conditions in large and small blood vessels for studying molecular transport across the endothelial monolayer. The device builds upon previously demonstrated integrated microfluidic loop design by: (a) introducing nanoscale pores in the substrate membrane to enable transmembrane molecular transport, (b) transforming the substrate membrane into a nanofibrous matrix for 3D smooth muscle cell (SMC) tissue culture, (c) integrating electrospinning fabrication methods, (d) engineering an invertible sandwich cell culture device architecture, and (e) devising a healthy co-culture mechanism for human arterial endothelial cell (HAEC) monolayer and multiple layers of human smooth muscle cells (HSMC) to accurately mimic arterial anatomy. Structural and mechanical characterization was conducted using confocal microscopy, SEM, stress/strain analysis, and infrared spectroscopy. Transport was characterized using FITC-Dextran hydraulic permeability protocol. Structure and transport characterization successfully demonstrate device viability as a physiologically relevant arterial mimic for testing transendothelial transport. Thus, our lab-on-a-brane provides a highly effective and efficient, yet considerably inexpensive, physiologically relevant alternative for pharmacokinetic evaluation; possibly reducing animals used in pre-clinical testing, clinical trials cost from false
Gravity localization on hybrid branes
Veras, D. F. S.; Cruz, W. T.; Maluf, R. V.; Almeida, C. A. S.
2016-03-01
This work deals with gravity localization on codimension-1 brane worlds engendered by compacton-like kinks, the so-called hybrid branes. In such scenarios, the thin brane behavior is manifested when the extra dimension is outside the compact domain, where the energy density is non-trivial, instead of asymptotically as in the usual thick brane models. The zero mode is trapped in the brane, as required. The massive modes, although not localized in the brane, have important phenomenological implications such as corrections to the Newton's law. We study such corrections in the usual thick domain wall and in the hybrid brane scenarios. By means of suitable numerical methods, we attain the mass spectrum for the graviton and the corresponding wavefunctions. The spectra possess the usual linearly increasing behavior from the Kaluza-Klein theories. Further, we show that the 4D gravitational force is slightly increased at short distances. The first eigenstate contributes highly for the correction to the Newton's law. The subsequent normalized solutions have diminishing contributions. Moreover, we find out that the phenomenology of the hybrid brane is not different from the usual thick domain wall. The use of numerical techniques for solving the equations of the massive modes is useful for matching possible phenomenological measurements in the gravitational law as a probe to warped extra dimensions.
Bergshoeff, E A; Townsend, P K; Bergshoeff, Eric A.; Gibbons, Gary W.; Townsend, Paul K.
2006-01-01
We show how, in heterotic M-theory, an M5-brane in the 11-dimensional bulk may end on an ``M9-brane'' boundary, the M5-brane boundary being a Yang monopole 4-brane. This possibility suggests various novel 5-brane configurations of heterotic M-theory, in particular a static M5-brane suspended between the two M9-brane boundaries, for which we find the asymptotic heterotic supergravity solution.
Electromagnetic Force on a Brane
Li, Li-Xin
2016-01-01
A fundamental assumption in the theory of brane world is that all matter and radiation are confined on the four-dimensional brane and only gravitons can propagate in the five-dimensional bulk spacetime. The brane world theory did not provide an explanation for the existence of electromagnetic fields and the origin of the electromagnetic field equation. In this paper, we propose a model for explaining the existence of electromagnetic fields on a brane and deriving the electromagnetic field equation. Similar to the case in Kaluza-Klein theory, we find that electromagnetic fields and the electromagnetic field equation can be derived from the five-dimensional Einstein field equation. However, the derived electromagnetic field equation differs from the Maxwell equation by containing a term with the electromagnetic potential vector coupled to the spacetime curvature tensor. So it can be considered as generalization of the Maxwell equation in a curved spacetime. The gravitational field equation on the brane is also ...
Smolyakov, Mikhail N.; Volobuev, Igor P.
2016-01-01
In this paper we examine, from the purely theoretical point of view and in a model-independent way, the case, when matter, gauge and Higgs fields are allowed to propagate in the bulk of five-dimensional brane world models with compact extra dimension, and the Standard Model fields and their interactions are supposed to be reproduced by the corresponding zero Kaluza-Klein modes. An unexpected result is that in order to avoid possible pathological behavior in the fermion sector, it is necessary to impose constraints on the fermion field Lagrangian. In the case when the fermion zero modes are supposed to be localized at one of the branes, these constraints imply an additional relation between the vacuum profile of the Higgs field and the form of the background metric. Moreover, this relation between the vacuum profile of the Higgs field and the form of the background metric results in the exact reproduction of the gauge boson and fermion sectors of the Standard Model by the corresponding zero mode four-dimensional effective theory in all the physically relevant cases, allowed by the absence of pathologies. Meanwhile, deviations from these conditions can lead either back to pathological behavior in the fermion sector or to a variance between the resulting zero mode four-dimensional effective theory and the Standard Model, which, depending on the model at hand, may, in principle, result in constraints putting the theory out of the reach of the present day experiments.
Observational constrains on the DGP brane-world model with a Gauss-Bonnet term in the bulk
Energy Technology Data Exchange (ETDEWEB)
He Jianhua [Department of Physics, Fudan University, 200433 Shanghai (China); Wang Bin [Department of Physics, Fudan University, 200433 Shanghai (China)], E-mail: wangb@fudan.edu.cn; Papantonopoulos, Eleftherios [Department of Physics, National Technical University of Athens, GR 157 73, Athens (Greece)], E-mail: lpapa@central.ntua.gr
2007-10-18
Using the data coming from the new 182 Gold type Ia supernova samples, the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey and the H(z) data, we have performed a statistical joint analysis of the DGP brane-world model with a high curvature Gauss-Bonnet term in the bulk. Consistent parameters estimations show that the Gauss-Bonnet-induced gravity model is a viable candidate to explain the observed acceleration of our universe.
DBI Action from Closed Strings and D-brane second Quantization
Kogan, I I; Kogan, Ian I.; Polyakov, Dimitri
2003-01-01
Brane-like vertex operators play an important role in a worldsheet formulation of D-branes and M-theory. In this paper we derive the DBI D-brane action from NSR closed string sigma-model with brane-like states. We also show that these operators carry RR charges and define D-brane wavefunctions in a second quantized formalism.
D-brane scattering and annihilation
D'Amico, Guido; Kleban, Matthew; Schillo, Marjorie
2014-01-01
We study the dynamics of parallel brane-brane and brane-antibrane scattering in string theory in flat spacetime, focusing on the pair production of open strings that stretch between the branes. We are particularly interested in the case of scattering at small impact parameter $b < l_s$, where there is a tachyon in the spectrum when a brane and an antibrane approach within a string length. Our conclusion is that despite the tachyon, branes and antibranes can pass through each other with only a very small probability of annihilating, so long as $g_s$ is small and the relative velocity $v$ is neither too small nor too close to 1. Our analysis is relevant also to the case of charged open string production in world-volume electric fields, and we make use of this T-dual scenario in our analysis. We briefly discuss the application of our results to a stringy model of inflation involving moving branes.
Way-out to the Gravitino problem in intersecting D-brane Pati-Salam models
Addazi, Andrea
2016-01-01
We discuss the gravitino problem in contest of the Exotic see-saw mechanism for neutrinos and Leptogenesis, UV completed by intersecting D-branes Pati-Salam models. In the Exotic see-saw model, supersymmetry is broken at high scales $M_{SUSY}>10^{9}\\, \\rm GeV$ and this seems in contradiction with gravitino bounds from inflation and baryogenesis. However, if gravitino is the Lightest Stable Supersymmetric Particle, it will not decay into other SUSY particles, avoiding the gravitino problem and providing a good Cold Dark Matter. Gravitini are Super Heavy Dark Particles and they can be produced by non-adiabatic expansion during inflation. Intriguingly, from bounds on the correct abundance of dark matter, we also constrain the neutrino sector. We set a limit on the exotic instantonic coupling of $<10^{-2}\\div 10^{-3}$. This also sets important constrains on the Calabi-Yau compactifications and on the string scale. This model strongly motivates very high energy DM indirect detection of neutrini and photons of $...
Inflation at the maxima of the potential inspired by brane models
Germán, G
2003-01-01
We construct a two-stage inflationary model which can accommodate early inflation at a scale $\\Lambda_1$ as well as a second stage of inflation (quintessence) at $\\Lambda_2$ with a single scalar field $\\phi$. We use a symmetric potential, valid in a frictionless world, in which the two inflationary periods have exactly the same scale, i.e. $\\Lambda_1=\\Lambda_2$. However, we see today $\\Lambda_1 \\gg \\Lambda_2$ due to the friction terms (expansion of the universe and interaction with matter). These type of models can be motivated from brane or supergravity models. Inflation occurs close to the maxima of the potential. As a consequence both inflations are necessarily finite. This opens the interesting possibility that the second inflation has already or is about to end. A first inflation is produced when fluctuations displace the inflaton field from its higher maximum rolling down the potential as in new inflation. Instead of rolling towards a global minimum the inflaton approaches a lower maximum where a second...
Gravity localization on hybrid branes
Veras, D F S; Maluf, R V; Almeida, C A S
2015-01-01
This work deals with gravity localization on codimension-1 brane worlds engendered by compacton-like kinks, the so-called hybrid branes. In such scenarios, the thin brane behaviour is manifested when the extra dimension is outside the compact domain, where the energy density is non-trivial, instead of asymptotically as in the usual thick brane models. The zero mode is trapped in the brane, as required. The massive modes, although are not localized in the brane, have important phenomenological implications such as corrections to the Newton's law. We study such corrections in the usual thick domain wall and in the hybrid brane scenarios. By means of suitable numerical methods, we attain the mass spectrum for the graviton and the corresponding wavefunctions. The spectra possess the usual linearly increasing behaviour from the Kaluza-Klein theories. Further, we show that the 4D gravitational force is slightly increased at short distances. The first eigenstate contributes highly for the correction to the Newton's ...
International Nuclear Information System (INIS)
D-branes, topological defects in string theory on which string endpoints can live, may give new insight into the understanding of the cosmological evolution of the Universe at early epochs. We analyze the dynamics of D-branes in curved backgrounds and discuss the parameter space of M-theory as a function of the coupling constant and of the curvature of the Universe. We show that D-branes may be efficiently produced by gravitational effects. Furthermore, in curved space-times the transverse fluctuations of the D-branes develop a tachyonic mode and when the fluctuations grow larger than the horizon the branes become tensionless and break up. This signals a transition to a new regime. We discuss the implications of our findings for the singularity problem present in string cosmology, suggesting the existence of a limiting value for the curvature which is in agreement with the value suggested by the cosmological version of the holography principle. We also comment on possible implications for the so-called brane world scenario, where the Standard Model gauge and matter fields live inside some branes while gravitons live in the bulk
Renormalizability of the open string sigma model and emergence of D-branes
International Nuclear Information System (INIS)
Rederiving the one-loop divergences for the most general coupling of the open string sigma model by the heat kernel technique, we distinguish the classical background field from the mean field of the effective action. The latter is arbitrary, i.e. does not fulfil the boundary conditions. As a consequence a new divergent counter term strongly suggests the introduction of another external one-form field (beside the usual gauge field), coupled to the normal derivative at the boundary. Actually such a field has been proposed in the literature for different reasons, but its full impact never seems to have thoroughly investigated before. The β function for the resulting renormalizable model is calculated and the consequences are discussed, including the ones for the Born-Infeld action. The most exciting property of the new coupling is that it enters the coefficient in front of the normal derivative in Neumann boundary conditions. For certain values of the background fields this coefficient vanishes, leading to Dirichlet boundary conditions. This provides a natural mechanism for the emergence of D-branes. (author)
LHC Phenomenology and Cosmology of String-Inspired Intersecting D-Brane Models
Anchordoqui, Luis A; Goldberg, Haim; Huang, Xing; Lust, Dieter; Taylor, Tomasz R; Vlcek, Brian
2012-01-01
We discuss the phenomenology and cosmology of a Standard-like Model inspired by string theory, in which the gauge fields are localized on D-branes wrapping certain compact cycles on an underlying geometry, whose intersection can give rise to chiral fermions. The energy scale associated with string physics is assumed to be near the Planck mass. To develop our program in the simplest way, we work within the construct of a minimal model with gauge-extended sector U (3)_B \\times Sp (1)_L \\times U (1)_{I_R} \\times U (1)_L. The resulting U (1) content gauges the baryon number B, the lepton number L, and a third additional abelian charge I_R which acts as the third isospin component of an SU(2)_R. All mixing angles and gauge couplings are fixed by rotation of the U(1) gauge fields to a basis diagonal in hypercharge Y and in an anomaly free linear combination of I_R and B-L. The anomalous $Z'$ gauge boson obtains a string scale St\\"uckelberg mass via a 4D version of the Green-Schwarz mechanism. To keep the realizatio...
Koivisto, Tomi; Wills, Danielle; Zavala, Ivonne
2014-01-01
Disformally coupled cosmologies arise from Dirac-Born-Infeld actions in Type II string theories, when matter resides on a moving hidden sector D-brane. Since such matter interacts only very weakly with the standard model particles, this scenario can provide a natural origin for the dark sector of the universe with a clear geometrical interpretation: dark energy is identified with the scalar field associated to the D-brane's position as it moves in the internal space, acting as quintessence, w...
Kamali, Vahid
2015-01-01
Tachyon inflationary universe model on the brane in the context of warm inflation is studied. In slow-roll approximation and in longitudinal gauge, we find the primoradial perturbation spectrums for this scenario. We also present the general expressions of the tensor-scalar ratio, scalar spectral index and its running. We develop our model by using exponential potential, the characteristics of this model are calculated in great details. We also study our model in the context of intermediate (where scale factor expands as: $a=a_0\\exp(At^f)$) and logamediate (where the scale factor expands as: $a=a_0\\exp(A[\\ln t]^{\
Nucleation of {sup (4)}R brane universes
Energy Technology Data Exchange (ETDEWEB)
Cordero, Ruben [Departamento de FIsica, Escuela Superior de FIsica y Matematicas del IPN, Unidad Adolfo Lopez Mateos, Edificio 9, 07738 Mexico, DF (Mexico); Rojas, EfraIn [Facultad de FIsica e Inteligencia Artificial, Universidad Veracruzana, Sebastian Camacho 5, Xalapa, Veracruz, 91000 (Mexico)
2004-09-07
The creation of brane universes induced by a totally antisymmetric tensor living in a fixed background spacetime is presented, where a term involving the intrinsic curvature of the brane is considered. A canonical quantum mechanical approach employing the Wheeler-DeWitt equation is used. The probability nucleation for the brane is calculated by means of the corresponding instanton and the WKB approximation. Some cosmological implications from the model are presented.
Electromagnetic force on a brane
Li, Li-Xin
2016-11-01
A fundamental assumption in the theory of brane world is that all matter and radiation are confined on the four-dimensional brane and only gravitons can propagate in the five-dimensional bulk spacetime. The brane world theory did not provide an explanation for the existence of electromagnetic fields and the origin of the electromagnetic field equation. In this paper, we propose a model for explaining the existence of electromagnetic fields on a brane and deriving the electromagnetic field equation. Similar to the case in Kaluza–Klein theory, we find that electromagnetic fields and the electromagnetic field equation can be derived from the five-dimensional Einstein field equation. However, the derived electromagnetic field equation differs from the Maxwell equation by containing a term with the electromagnetic potential vector coupled to the spacetime curvature tensor. So it can be considered as generalization of the Maxwell equation in a curved spacetime. The gravitational field equation on the brane is also derived with the stress–energy tensor for electromagnetic fields explicitly included and the Weyl tensor term explicitly expressed with matter fields and their derivatives in the direction of the extra-dimension. The model proposed in the paper can be regarded as unification of electromagnetic and gravitational interactions in the framework of brane world theory.
Ellwood, I
2005-01-01
We construct a general map between a Dp-brane with magnetic flux and a matrix configuration of D0-branes, by showing how one can rewrite the boundary state of the Dp-brane in terms of its D0-brane constituents. This map gives a simple prescription for constructing the matrices of fuzzy spaces corresponding to branes of arbitrary shape and topology. Since we explicitly identify the D0-brane degrees of freedom on the brane, we also derive the D0-brane charge of the brane in a very direct way including the A-genus term. As a check on our formalism, we use our map to derive the abelian-Born-Infeld equations of motion from the action of the D0-brane matrices.
Energy Technology Data Exchange (ETDEWEB)
Creutzig, Thomas
2009-06-15
In this thesis we initiate a systematic study of branes in Wess-Zumino-Novikov-Witten models with Lie supergroup target space. We start by showing that a branes' worldvolume is a twisted superconjugacy class and construct the action of the boundary WZNW model. Then we consider symplectic fermions and give a complete description of boundary states including twisted sectors. Further we show that the GL(1 vertical stroke 1) WZNW model is equivalent to symplectic fermions plus two scalars. We then consider the GL(1 vertical stroke 1) boundary theory. Twisted and untwisted Cardy boundary states are constructed explicitly and their amplitudes are computed. In the twisted case we find a perturbative formulation of the model. For this purpose the introduction of an additional fermionic boundary degree of freedom is necessary. We compute all bulk one-point functions, bulk-boundary two-point functions and boundary three-point functions. Logarithmic singularities appear in bulk-boundary as well as pure boundary correlation functions. Finally we turn to world-sheet and target space supersymmetric models. There is N=2 superconformal symmetry in many supercosets and also in certain supergroups. In the supergroup case we find some branes that preserve the topological A-twist and some that preserve the B-twist. (orig.)
International Nuclear Information System (INIS)
In this thesis we initiate a systematic study of branes in Wess-Zumino-Novikov-Witten models with Lie supergroup target space. We start by showing that a branes' worldvolume is a twisted superconjugacy class and construct the action of the boundary WZNW model. Then we consider symplectic fermions and give a complete description of boundary states including twisted sectors. Further we show that the GL(1 vertical stroke 1) WZNW model is equivalent to symplectic fermions plus two scalars. We then consider the GL(1 vertical stroke 1) boundary theory. Twisted and untwisted Cardy boundary states are constructed explicitly and their amplitudes are computed. In the twisted case we find a perturbative formulation of the model. For this purpose the introduction of an additional fermionic boundary degree of freedom is necessary. We compute all bulk one-point functions, bulk-boundary two-point functions and boundary three-point functions. Logarithmic singularities appear in bulk-boundary as well as pure boundary correlation functions. Finally we turn to world-sheet and target space supersymmetric models. There is N=2 superconformal symmetry in many supercosets and also in certain supergroups. In the supergroup case we find some branes that preserve the topological A-twist and some that preserve the B-twist. (orig.)
与额外维相关的膜宇宙模型%A Brane Universe Model with Extra Dimension
Institute of Scientific and Technical Information of China (English)
李希国; 贾贝
2011-01-01
We summarized both the general covariant energy-momentum and angular momentum conservation law in the gravitational system and analyzed the general covariant energy-momentum tensor of the gravitational system in general five-dimensional cosmological in brane-universe models.After calculating this energy-momentum for the cosmological generalization of the Randall-Sundrum（RS） model which includes the original RS model as the static limit,we are able to show that the weakness of the gravitation on the ＂visible＂ brane is a general feature of this model.This is the origin of the gauge hierarchy from a gravitational point of view.Our results are also consistent with the fact that a gravitational system has vanishing total energy.We also discussed the properties of the general covariant angular momentum in five-dimensional brane-universe model.With calculation of the total angular momentum of this model,we analyzed the properties of the total angular momentum in the inflationary RS model.We pointed that the space-like components of the total angular momentum are zero while the others are non-zero,which agrees with the results from ordinary RS model.We also investigated the bulk cosmological constant and brane vacuum energies in RS model.We show that the five-dimensional bulk cosmological constant and the vacuum energies of the two branes could take their natural values.Finally we argued how we can generate a small four-dimensional effective cosmological constant on the branes by modifying the original RS model.%对引力场的能量-动量和角动量守恒定律研究进展进行了总结。依此探讨了一般五维时空膜宇宙模型中的能量-动量张量、角动量张量以及它们的守恒定律。通过计算一个膜宇宙模型中的能动张量,论证了该模型中＂可见膜＂上的引力非常弱,这可认为是从引力的角度反映了规范层次问题。结果与一般的结论,即引力系统总能量为零是一致的。同时,分析
A varying-e brane world cosmology
International Nuclear Information System (INIS)
We study a varying electric charge brane world cosmology in the RS2 model obtained from a varying-speed-of-light brane world cosmology by redefining the system of units. We elaborate conditions under which the flatness problem and the cosmological constant problem can be resolved by such cosmological model (author)
Consistency Conditions for Brane Worlds in Arbitrary Dimensions
Leblond, F; Winters, D J; Leblond, Frederic; Myers, Robert C.; Winters, David J.
2001-01-01
We consider ``brane world sum rules'' for compactifications involving an arbitrary number of spacetime dimensions. One of the most striking results derived from such consistency conditions is the necessity for negative tension branes to appear in five--dimensional scenarios. We show how this result is easily evaded for brane world models with more than five dimensions. As an example, we consider a novel realization of the Randall--Sundrum scenario in six dimensions involving only positive tension branes.
Sakatani, Yuho
2016-01-01
We propose a novel approach to the brane worldvolume theory based on the geometry of extended field theories; double field theory and exceptional field theory. We demonstrate the effectiveness of this approach by showing that one can reproduce the conventional bosonic string/membrane actions, and the M5-brane action in the weak field approximation. At a glance, the proposed 5-brane action without approximation looks different from the known M5-brane actions, but it is consistent with the known non-linear self-duality relation, and it may provide a new formulation of a single M5-brane action. Actions for exotic branes are also discussed.
Directory of Open Access Journals (Sweden)
V. Kamali
2016-01-01
Full Text Available Tachyon inflationary universe model on the brane in the context of warm inflation is studied. In slow-roll approximation and in longitudinal gauge, we find the primordial perturbation spectrums for this scenario. We also present the general expressions of the tensor-scalar ratio, scalar spectral index, and its running. We develop our model by using exponential potential; the characteristics of this model are calculated in great detail. We also study our model in the context of intermediate (where scale factor expands as a=a0expAtf and logamediate (where the scale factor expands as a=a0expAlntν models of inflation. In these two sectors, dissipative parameter is considered as a constant parameter and a function of tachyon field. Our model is compatible with observational data. The parameters of the model are restricted by Planck data.
Heun equation in a 5D sine-Gordon brane-world model with dilaton
Energy Technology Data Exchange (ETDEWEB)
Cunha, M.S.; Christiansen, H. [Universidade Estadual do Ceara (GFT/UECE), CE (Brazil). Grupo de Fisica Teorica
2011-07-01
Full text: In a brane-world scenario we find the propagation modes of the gauge field in a five-dimensional space-time. We adopt warping factors of the Randall-Sundrum type which are appropriate to regularize the hierarchy problem without imposing finite compactified extra dimensions. The existence and localization of gauge particles in the ordinary four-dimensional world is studied in detail on a thick brane derived out from the equations of motion of an action with a sine-Gordon potential contribution. Maxwell zero modes together with torsion effective fields are then obtained in a gravity-dilaton background inspired in close string theories. The dilaton plays a crucial role in order that the gauge field gets localized in a conformally invariant context. Kaluza-Klein massive states are also computed and, depending on certain parameters like dilaton coupling constant and asymptotic curvature, we are able to do it fully analytically. In a general approach we find that the solutions are of the Heun type. In some specific cases we can show that the Heun general solutions can be transformed into hypergeometric functions. In others, confluent Heun solutions can be transformed into simpler functions like Mathieu functions. Exact mass spectra are found in several cases. In others, we performed numerical calculations that show a well behaved phenomenology as well. In all the cases, Kaluza-Klein modes are strongly suppressed on the brane in the effective four-dimensional theory. (author)
M5-branes on S^2 x M_4: Nahm's Equations and 4d Topological Sigma-models
Assel, Benjamin; Wong, Jin-Mann
2016-01-01
We study the 6d N=(0,2) superconformal field theory, which describes multiple M5-branes, on the product space S^2 x M_4, and suggest a correspondence between a 2d N=(0,2) half-twisted gauge theory on S^2 and a topological sigma-model on the four-manifold M_4. To set up this correspondence, we determine in this paper the dimensional reduction of the 6d N=(0,2) theory on a two-sphere and derive that the four-dimensional theory is a sigma-model into the moduli space of solutions to Nahm's equations, or equivalently the moduli space of k-centered SU(2) monopoles, where k is the number of M5-branes. We proceed in three steps: we reduce the 6d abelian theory to a 5d Super-Yang-Mills theory on I x M_4, with I an interval, then non-abelianize the 5d theory and finally reduce this to 4d. In the special case, when M_4 is a Hyper-Kahler manifold, we show that the dimensional reduction gives rise to a topological sigma-model based on tri-holomorphic maps. Deriving the theory on a general M_4 requires knowledge of the met...
Gravitomagnetism in Brane-Worlds
Nayeri, A; Nayeri, Ali; Reynolds, Adam
2001-01-01
In this paper we discuss a physical observable which is drastically different in a brane-world scenario. To date, the Randall-Sundrum model seems to be consistent with all experimental tests of general relativity. Specifically, we examine the so-called gravitomagnetic effect in the context of the Randall-Sundrum (RS) model. This treatment, of course, assumes the recovery of the Kerr metric in brane-worlds which we have found to the first order in the ratio of the brane separation to the radius of the AdS$_5$, $(\\ell/r)$. We first show that the second Randall-Sundrum model of one brane leaves the gravitomagnetic effect unchanged. Then, we consider the two-brane scenario of the original Randall-Sundrum proposal and show that the magnitude of the gravitomagnetic effect depends heavily on the ratio of $(\\ell/r)$. Such dependence is a result of the geometrodynamic spacetime and does not appear in static scenarios. We hope that we will be able to test this proposal experimentally with data from NASA's Gravity Probe...
Thick brane solitons breaking $Z_2$ symmetry
Peyravi, Marzieh; Lobo, Francisco S N
2015-01-01
New soliton solutions for thick branes in 4 + 1 dimensions are considered in this article. In particular, brane models based on the sine-Gordon (SG), $\\varphi^{4}$ and $\\varphi^{6}$ scalar fields are investigated; in some cases $Z_{2}$ symmetry is broken. Besides, these soliton solutions are responsible for supporting and stabilizing the thick branes. In these models, the origin of the symmetry breaking resides in the fact that the modified scalar field potential may have non-degenerate vacuua and these non-degenerate vacuua determine the cosmological constant on both sides of the brane. At last, in order to explore the particle motion in the neighborhood of the brane, the geodesic equations along the fifth dimension are studied.
Cremonesi, Stefano; Seong, Rak-Kyeong
2013-01-01
We classify the first few brane tilings on a genus 2 Riemann surface and identify their toric Calabi-Yau moduli spaces. These brane tilings are extensions of tilings on the 2-torus, which represent one of the largest known classes of 4d N=1 superconformal field theories for D3-branes. The classification consists of 16 distinct genus 2 brane tilings with up to 8 quiver fields and 4 superpotential terms. The Higgs mechanism is used to relate the different theories.
The Dynamics of Test Particles and Pointlike Gyroscopes in the Brane World and Other 5D Models
Seahra, S S
2002-01-01
We study the dynamics of test particles and pointlike gyroscopes in 5D manifolds like those used in the Randall-Sundrum brane world and non-compact Kaluza-Klein models. Our analysis is based on a covariant foliation of the manifold using 3+1 dimensional spacetime slices orthogonal to the extra dimension, and is hence similar to the ADM 3+1 split in ordinary general relativity. We derive gauge invariant equations of motion for freely-falling test particles in the 5D and 4D affine parameterizations and contrast these results with previous work concerning the so-called ``fifth force''. Motivated by the conjectured localization of matter fields on a 3-brane, we derive the form of the classical non-gravitational force required to confine particles to a 4D hypersurface and show that the resulting trajectories are geometrically identical to the spacetime geodesics of Einstein's theory. We then discuss the issue of determining the 5D dynamics of a torque-free spinning body in the point-dipole approximation, and then ...
Brane Stabilization and Regionality of Extra Dimensions
Jacobs, David M; Tolley, Andrew J
2012-01-01
Extra dimensions are a common feature of beyond the Standard Model physics. In a braneworld scenario, local physics on the brane can depend strongly on the brane's location within the bulk. Generically, the relevant properties of the bulk manifold for the physics on/of the brane are neither local nor global, but depend on the structure of finite regions of the bulk, even for locally homogeneous and isotropic bulk geometries. In a recent work, various mechanisms (in a braneworld context) were considered to stabilize the location of a brane within bulk spaces of non-trivial topology. In this work we elaborate on and generalize that work by considering additional bulk and brane dimensionalities as well as different boundary conditions on the bulk scalar field that provides a Casimir force on the brane, providing further insight on this effect. In D=2+1 (D=5+1) we consider both local and global contributions to the effective potential of a 1-brane (4-brane) wrapped around both the 2-dimensional hyperbolic horn an...
Wavefunctions on magnetized branes in the conifold
Abe, Hiroyuki; Oikawa, Akane; Otsuka, Hajime
2016-07-01
We study wavefunctions on D7-branes with magnetic fluxes in the conifold. Since some supersymmetric embeddings of D-branes on the AdS 5 × T 1,1 geometry are known, we consider one of the embeddings, especially the spacetime filling D7-branes in which (a part of) the standard model is expected to be realized. The explicit form of induced metric on the D7-branes allows us to solve the Laplace and Dirac equations to evaluate matter wavefunctions in extra dimensions analytically. We find that the zeromode wavefunctions can be localized depending on the configuration of magnetic fluxes on D7-branes, and show some phenomenological aspects.
Enveloping branes and brane-world singularities
Energy Technology Data Exchange (ETDEWEB)
Antoniadis, Ignatios; Cotsakis, Spiros [CERN-Theory Division, Department of Physics, Geneva 23 (Switzerland); Klaoudatou, Ifigeneia [University of the Aegean, Research Group of Geometry, Dynamical Systems and Cosmology, Department of Information and Communication Systems Engineering, Samos (Greece)
2014-12-01
The existence of envelopes is studied for systems of differential equations in connection with the method of asymptotic splittings which allows one to determine the singularity structure of the solutions. The result is applied to brane-worlds consisting of a 3-brane in a five-dimensional bulk, in the presence of an analog of a bulk perfect fluid parameterizing a generic class of bulk matter. We find that all flat brane solutions suffer from a finite-distance singularity contrary to previous claims. We then study the possibility of avoiding finite-distance singularities by cutting the bulk and gluing regular solutions at the position of the brane. Further imposing physical conditions such as finite Planck mass on the brane and positive energy conditions on the bulk fluid, excludes, however, this possibility as well. (orig.)
Brane content of branes' states
Mkrtchyan, Ruben
2003-04-01
The problem of decomposition of unitary irreps of (super)tensorial (i.e., extended with tensorial charges) Poincaré algebra w.r.t. its different subalgebras is considered. This requires calculation of little groups for different configurations of tensor charges. Particularly, for preon states (i.e., states with maximal supersymmetry) in different dimensions the particle content is calculated, i.e., the spectrum of usual Poincaré representations in the preon representation of tensorial Poincaré. At d=4 results coincide with (and may provide another point of view on) the Vasiliev's results in field theories in generalized space-time. The translational subgroup of little groups of massless particles and branes is shown to be (and coincide with, at d=4) a subgroup of little groups of “pure branes” algebras, i.e., tensorial Poincaré algebras without vector generators. At 11d it is shown that, contrary to lower dimensions, spinors are not homogeneous space of Lorentz group, and one have to distinguish at least 7 different kinds of preons.
Directory of Open Access Journals (Sweden)
Arthur Hebecker
2014-10-01
Full Text Available We analyze string-theoretic large-field inflation in the regime of spontaneously-broken supergravity with conventional moduli stabilization by fluxes and non-perturbative effects. The main ingredient is a shift-symmetric Kähler potential, supplemented by flux-induced shift symmetry breaking in the superpotential. The central technical observation is that all these features are present for D7-brane position moduli in Type IIB orientifolds, potentially allowing for a realization of the axion monodromy proposal in a string theory compactification. Furthermore, our model is explicit enough to address issues of control and moduli stabilization quantitatively. On the one hand, in the large complex structure regime the D7-brane position moduli inherit a shift symmetry from their mirror-dual Type IIA Wilson lines. On the other hand, the Type IIB flux superpotential generically breaks this shift symmetry and allows, by appealing to the large flux discretuum, to tune the relevant coefficients to be small. The shift-symmetric direction in D7-brane moduli space can then play the role of the inflaton: While the D7-brane circles a certain trajectory on the Calabi–Yau many times, the corresponding F-term energy density grows only very slowly, thanks to the above-mentioned tuning of the flux. To be successful our model requires that the dilaton, all complex structure moduli and all D7-brane moduli except the inflaton are fixed at leading order by fluxes. Then the large-field inflationary trajectory can be realized in a regime where Kähler, complex structure and other brane moduli are stabilized in a conventional manner, as we demonstrate using the example of the Large Volume Scenario.
Hebecker, Arthur; Kraus, Sebastian C.; Witkowski, Lukas T.
2014-10-01
We analyze string-theoretic large-field inflation in the regime of spontaneously-broken supergravity with conventional moduli stabilization by fluxes and non-perturbative effects. The main ingredient is a shift-symmetric Kähler potential, supplemented by flux-induced shift symmetry breaking in the superpotential. The central technical observation is that all these features are present for D7-brane position moduli in Type IIB orientifolds, potentially allowing for a realization of the axion monodromy proposal in a string theory compactification. Furthermore, our model is explicit enough to address issues of control and moduli stabilization quantitatively. On the one hand, in the large complex structure regime the D7-brane position moduli inherit a shift symmetry from their mirror-dual Type IIA Wilson lines. On the other hand, the Type IIB flux superpotential generically breaks this shift symmetry and allows, by appealing to the large flux discretuum, to tune the relevant coefficients to be small. The shift-symmetric direction in D7-brane moduli space can then play the role of the inflaton: While the D7-brane circles a certain trajectory on the Calabi-Yau many times, the corresponding F-term energy density grows only very slowly, thanks to the above-mentioned tuning of the flux. To be successful our model requires that the dilaton, all complex structure moduli and all D7-brane moduli except the inflaton are fixed at leading order by fluxes. Then the large-field inflationary trajectory can be realized in a regime where Kähler, complex structure and other brane moduli are stabilized in a conventional manner, as we demonstrate using the example of the Large Volume Scenario.
M5-branes on S 2 × M 4: Nahm's equations and 4d topological sigma-models
Assel, Benjamin; Schäfer-Nameki, Sakura; Wong, Jin-Mann
2016-09-01
We study the 6d N = (0 , 2) superconformal field theory, which describes multiple M5-branes, on the product space S 2 × M 4, and suggest a correspondence between a 2d N = (0 , 2) half-twisted gauge theory on S 2 and a topological sigma-model on the four-manifold M 4. To set up this correspondence, we determine in this paper the dimensional reduction of the 6d N = (0 , 2) theory on a two-sphere and derive that the four-dimensional theory is a sigma-model into the moduli space of solutions to Nahm's equations, or equivalently the moduli space of k-centered SU(2) monopoles, where k is the number of M5-branes. We proceed in three steps: we reduce the 6d abelian theory to a 5d Super-Yang-Mills theory on I × M 4, with I an interval, then non-abelianize the 5d theory and finally reduce this to 4d. In the special case, when M 4 is a Hyper-Kähler manifold, we show that the dimensional reduction gives rise to a topological sigma-model based on tri-holomorphic maps. Deriving the theory on a general M 4 requires knowledge of the metric of the target space. For k = 2 the target space is the Atiyah-Hitchin manifold and we twist the theory to obtain a topological sigma-model, which has both scalar fields and self-dual two-forms.
Can we live on a D-brane? -- Effective theory on a self-gravitating D-brane --
Shiromizu, T; Onda, S; Torii, T; Torii, Takashi
2003-01-01
We consider a D-brane coupled with gravity in type IIB supergravity on S^5 and derive the effective theory on the D-brane in two different ways, that is, holographic and geometrical projection methods. We find that the effective equations on the brane obtained by these methods coincide. The theory on the D-brane described by the Born-Infeld action is not like Einstein-Maxwell theory in the lower order of the gradient expansion, i.e., the Maxwell field does not appear in the theory. Thus the careful analysis and statement for cosmology on self-gravitating D-brane should be demanded in realistic models.
F(R) bouncing cosmology with future singularity in brane-anti-brane system
Sepehri, Alireza; Pradhan, Anirudh; Shoorvazi, Somayyeh
2016-02-01
Recently Odintsov and Oikonomou (Phys. Rev. D 92:024016, 2015b) proposed the origin of a Type IV singular bounce in a modified gravity and found an explicit form of F(R) which can generate this type of bouncing cosmological evolution. In this paper, we construct their model in string theory and show that interaction between branes is the main cause of F(R) bouncing cosmology. In our technique, N fundamental strings decay first to N M0-anti-M0-brane then, M0-branes link to each other, originate and form an M3-anti-M3 system. Our universe is located on one of these M3-branes and interact with the universe on another M3-brane via some scalars. The branes in this system wrap around each other and form a compacted system. This process causes to a contraction of universes and produces a contraction branch in a F(R) bouncing model of cosmology. Also, the relevant actions of compacted M3-branes include higher order of derivatives which lead to communication relations in generalized uncertainty principle. On the other hand, branes and anti-branes absorb each other, the radius of compactification is reduced, some of scalars gain negative square masses and become tachyons. This system is unstable, broken and branes rebound to non-compact state during an expansion branch. With opening of branes, some other scalars achieve to tachyon phase and consequently, this epoch stops. This process may be repeated in different branches. In this theory, the Type IV singularity occurs at t = ts, which is the time of producing tachyons between two branches. It is observed that the derived model is in good agreement with recent Planck data (Ade et al. in arXiv:1502.02114 [astro-ph.CO], 2015 and in Astron. Astrophys. 571:A22, 2014) and obtain the bouncing point.
Cosmological Evolution of Brane World Moduli
Brax, P; Davis, A C; Rhodes, C S; Brax, Ph.
2003-01-01
We study cosmological consequences of non-constant brane world moduli in five dimensional brane world models with bulk scalars and two boundary branes. We focus on the case where the brane tension is an exponential function of the bulk scalar field, $U_b \\propto \\exp{(\\alpha \\phi)}$. In the limit $\\alpha \\to 0$, the model reduces to the two-brane model of Randall-Sundrum, whereas larger values of $\\alpha$ allow for a less warped bulk geometry. Using the moduli space approximation we derive the four-dimensional low-energy effective action from a supergravity-inspired five-dimensional theory. For arbitrary values of $\\alpha$, the resulting theory has the form of a bi-scalar-tensor theory. We show that, in order to be consistent with local gravitational observations, $\\alpha$ has to be small (less than $10^{-2}$) and the separation of the branes must be large. We study the cosmological evolution of the interbrane distance and the bulk scalar field for different matter contents on each branes. Our findings indica...
Localization of Gravitino Field on Thin Branes
Du, Yun-Zhi; Zhou, Xiang-Nan; Zhong, Yi; Liu, Yu-Xiao
2015-01-01
In this paper, we investigate the localization of a gravitino field on two kinds of thin branes, the Randall-Sundrum-1 (RS1) branes and the scalar-tensor branes. The coupled chiral equations for the Kaluza-Klein (KK) modes of a gravitino field are obtained by the gravitino chiral KK decompositions with the supersymmetry transformations.It is shown that, in the RS1 model for the left- and right-handed zero modes of the gravitino field, only one of them can be localized near one brane. For the massive modes, both chiral modes survive and the lower KK modes are localized near the IR brane from the four-dimensional physical coordinate point of view. For the scalar-tensor brane model, the localization of the gravitino chiral zero modes depends on the coupling parameter $\\lambda$, and they will be not localized around anyone brane within a certain range of the parameter $\\lambda$, which is quite different from the RS1 model. Furthermore, we also give the corresponding mass spectra of the massive KK gravitinos in th...
Bunster, Claudio
2015-01-01
We introduce a new kind of space-filling brane, which we term G-brane because its action is a descendant of the gravitational action. The G-brane is different from the Dirac or Nambu space-filling branes, and has interesting formal properties in any spacetime dimension D, which are exhibited. For D greater or equal than three, the G-brane possesses only gauge degrees of freedom, just as the Dirac or Nambu branes. For D=3 the G-brane yields a reformulation of gravitation theory in which the Hamiltonian constraints can be solved explicitly, while keeping the spacetime structure manifest. For D=2 the G-brane provides a realization of the conformal algebra in terms of two scalar fields and their conjugates, which possesses a classical central charge. In the G-brane reformulation of (2+1) gravity, the boundary degrees of freedom of the gravitational field in asymptotically Anti-de Sitter space appear as "matter" coupled to the (1+1) G-brane on the boundary.
Enveloping branes and brane-world singularities
Antoniadis, Ignatios; Klaoudatou, Ifigeneia
2014-01-01
The existence of envelopes is studied for systems of differential equations in connection with the method of asymptotic splittings which allows to determine the singularity structure of the solutions. The result is applied to braneworlds consisting of a 3-brane in a five-dimensional bulk, in the presence of an analog of a bulk perfect fluid parametrizing a generic class of bulk matter. We find that all flat brane solutions suffer from a finite distance singularity contrary to previous claims. We then study the possibility of avoiding finite distance singularities by cutting the bulk and gluing regular solutions at the position of the brane. Further imposing physical conditions such as finite Planck mass on the brane and positive energy conditions on the bulk fluid, excludes however this possibility, as well.
Brane actions and string dualities
Eyras, E; Lozano, Y; Ceresole, A; Kounnas, C; Lust, D; Theisen, S
1999-01-01
An effective action for the M9-brane is proposed. We study its relation with other branes via dualities. Among these, we find actions for branes which are not suggested by the central charges of the Type II superalgebras.
Supersymmetric Baryonic Branes
Gomis, J P; Simón, J; Townsend, P K; Gomis, Joaquim; Ramallo, Alfonso V.; Simon, Joan; Townsend, Paul K.
1999-01-01
We derive an energy bound for a `baryonic' D5-brane probe in the $adS_5\\times S^5$ background near the horizon of $N$ D3-branes. Configurations saturating the bound are shown to be 1/4 supersymmetric $S^5$-wrapped D5-branes with $N$ singularities at arbitrary positions. Previous results for $N$ coincident singularities are recovered as a special case. We derive a similar energy bound for a `baryonic' M5-brane probe in the background of $N$ M5-branes. Configurations saturating the bound are again 1/4 supersymmetric and, in the $adS_7\\times S^4$ near-horizon limit, provide a worldvolume realization of the `baryon string' vertex of the (2,0)-supersymmetric six-dimensional conformal field theory on coincident M5-branes. For the full M5-background we find a worldvolume realization of the Hannany-Witten effect in M-theory.
Revolving D-branes and spontaneous gauge-symmetry breaking
International Nuclear Information System (INIS)
We propose a new mechanism of spontaneous gauge-symmetry breaking in the world-volume theory of revolving D-branes around a fixed point of orbifolds. In this paper, we consider a simple model of the T6/Z3 orbifold on which we put D3-branes, D7-branes, and their anti-branes. The configuration breaks supersymmetry, but the Ramond–Ramond tadpole cancellation conditions are satisfied. A set of three D3-branes at an orbifold fixed point can separate from the point, but, when they move perpendicular to the anti-D7-branes put on the fixed point, they are pulled back due to an attractive interaction between the D3- and anti-D7-branes. In order to stabilize the separation of the D3-branes at nonzero distance, we consider revolution of the D3-branes around the fixed point. Then the gauge symmetry on the D3-branes is spontaneously broken, and the rank of the gauge group is reduced. The distance can be set at will by appropriately choosing the angular momentum of the revolving D3-branes, which should be determined by the initial condition of the cosmological evolution of the D-brane configurations. The distance corresponds to the vacuum expectation values of brane moduli fields in the world-volume theory and, if it is written as M/Ms2 in terms of the string scale Ms, the scale of gauge-symmetry breaking is given by M. Angular momentum conservation of revolving D3-branes assures the stability of the scale M against Ms
Khuri, R R
1996-01-01
We derive double dimensional reduction/oxidation in a framework where it is applicable to describe general non-static (and anisotropic) p-brane solutions. Given this procedure, we are able to relate the dynamical interaction potential for parallel extremal p-branes in D dimensions to that for extremal black holes in D-p dimensions. In particular, we find that to leading order the potential vanishes for all \\kappa-symmetric p-branes.
Brane World Cosmological Perturbations
Casali, A G; Wang, B; Casali, Adenauer G.; Abdalla, Elcio; Wang, Bin
2004-01-01
We consider a brane world and its gravitational linear perturbations. We present a general solution of the perturbations in the bulk and find the complete perturbed junction conditions for generic brane dynamics. We also prove that (spin 2) gravitational waves in the great majority of cases can only arise in connection with a non-vanishing anisotropic stress. This has far reaching consequences for inflation in the brane world. Moreover, contrary to the case of the radion, perturbations are stable.
Meson Strings and Flavor Branes
Bando, M; Terunuma, S; Bando, Masako; Sugamoto, Akio; Terunuma, Sachiko
2006-01-01
In a QCD-like string model based on D6 flavor branes in the presence of D4 color branes wrapping one of the compactified dimension on an $S^1$, the shape of meson strings in the five dimensional curved space as well as the potential between quark and anti-quark are investigated. The flavor branes on which both ends of a meson string live are assumed to be separated in this five dimensional space, depending on the values of the constituent quark masses. It is shown in this picture that the meson string with different flavors on both ends changes its shape at a critical distance. There is, however, no critical distance for the meson with the same flavors. At this critical distance the potential between quark and anti-quark with different flavors gives a point of reflection and changes its shape around this point. Accordingly, the attractive force between quark and anti-quark seems to become stronger when the distance of flavor branes connecting meson strings becomes larger. This indicates quark systems with dif...
Johnson, C V
2006-01-01
We present a class of solvable models that resemble string theories in many respects but have a strikingly different non-perturbative sector. In particular, there are no exponentially small contributions to perturbation theory in the string coupling, which normally are associated with branes and related objects. Perturbation theory is no longer an asymptotic expansion, and so can be completely re-summed to yield all the non-perturbative physics. We examine a number of other properties of the theories, for example constructing and examining the physics of loop operators, which can be computed exactly, and gain considerable understanding of the difference between these new theories and the more familiar ones, including the possibility of how to interpolate between the two types. Interestingly, the models we exhibit contain a family of zeros of the partition function which suggest a novel phase structure. The theories are defined naturally by starting with models that yield well-understood string theories and al...
A note on "Galactic rotation curves and brane world models" by Rahaman et al. [arXiv:0802.3453
Nandi, K K
2008-01-01
We show that circular orbits are stable in a recently proposed solution in brane world theory. However, the solution does not produce attractive gravity in the halo. These features are contrasted with another solution in a different theory.
On multiple M2-brane model(s and its N=8 Superspace Formulation(s
Directory of Open Access Journals (Sweden)
I. A. Bandos
2010-01-01
Full Text Available We give a brief review of Bagger-Lambert-Gustavsson (BLG model, with emphasis on its version invariant under the volume preserving diffeomorphisms (SDiff3 symmetry. We describe the on-shell superfield formulation of this SDiff3 BLG model in standard N = 8, d = 3 superspace, as well as its superfield action in the pure spinor N = 8 superspace. We also briefly address the Aharony-Bergman-Jafferis-Maldacena (ABJM/ABJ model invariant under SU(Mk × SU(N−k gauge symmetry, and discuss the possible form of their N = 6 and, for the case of Chern-Simons level k = 1, 2, N = 8 superfield equations.
Brane-world cosmology and inflation
Indian Academy of Sciences (India)
Misao Sasaki
2004-10-01
There has been substantial progress in brane-world cosmology in recent years. Much attention has been particularly paid to the second Randall–Sundrum (RS2) scenario in which a single positive-tension brane is embedded in a five-dimensional space-time, called the bulk, with a negative cosmological constant. This brane-world scenario is quite attractive because of the non-trivial geometry in the bulk and because it successfully gives four-dimensional general relativity in the low energy limit. After reviewing basic features of the RS2 scenario, we consider a brane-world inflation model driven by the dynamics of a scalar field living in the five-dimensional bulk, the so-called bulk inflaton model. An intriguing feature of this model is that the projection of the bulk inflaton on the brane behaves just like an ordinary inflaton in four dimensions in the low energy regime, 2 ℓ2 ≪ 1, where is the Hubble expansion rate of the brane and ℓ is the curvature radius of the bulk. We then discuss the cosmological perturbation on superhorizon scales in this model. We find that, even under the presence of spatial inhomogeneities, the model is indistinguishable from the standard four-dimensional inflation to (2 ℓ2). That is, the difference may appear only at O(4 ℓ4).
Localization of massive and massless fermion on two field brane
Farokhtabar, A
2016-01-01
In this paper we study fermion localization and resonances on a special type of braneworld model supporting brane splitting. In such models one can construct multi-wall branes which cause considerable simplification in field equations. We use a polynomial superpotential to construct this brane. The suitable Yukawa coupling between the background scalar field and localized fermion is determined. The massive fermion resonance spectrum is obtained. The number of resonances is increased for higher values of Yukawa coupling.
Everett, L; King, S F
2000-01-01
We examine the flavor structure of the trilinear superpotential couplings which can result from embedding the Standard Model within D brane sectors in Type IIB orientifold models, which are examples within the Type I string framework. We find in general that the allowed flavor structures of the Yukawa coupling matrices to leading order are given by basic variations on the "democratic" texture ansatz. In certain interesting cases, the Yukawa couplings have a novel structure in which a single right-handed fermion couples democratically at leading order to three left-handed fermions. We discuss the viability of such a ``single right-handed democracy'' in detail; remarkably, even though there are large mixing angles in the u,d sectors separately, the CKM mixing angles are small. The analysis demonstrates the ways in which the Type I superstring framework can provide a rich setting for investigating novel resolutions to the flavor puzzle.
Towards Geometric D6-Brane Model Building on non-Factorisable Toroidal $\\mathbb{Z}_4$-Orbifolds
Berasaluce-González, Mikel; Seifert, Alexander
2016-01-01
We present a geometric approach to D-brane model building on the non-factorisable torus backgrounds of $T^6/\\mathbb{Z}_4$, which are $A_3 \\times A_3$ and $A_3 \\times A_1 \\times B_2$. Based on the counting of `short' supersymmetric three-cycles per complex structure {\\it vev}, the number of physically inequivalent lattice orientations with respect to the anti-holomorphic involution ${\\cal R}$ of the Type IIA/$\\Omega\\cal{R}$ orientifold can be reduced to three for the $A_3 \\times A_3$ lattice and four for the $A_3 \\times A_1 \\times B_2$ lattice. While four independent three-cycles on $A_3 \\times A_3$ cannot accommodate phenomenologically interesting global models with a chiral spectrum, the eight-dimensional space of three-cycles on $A_3 \\times A_1 \\times B_2$ is rich enough to provide for particle physics models, with several globally consistent two- and four-generation Pati-Salam models presented here. We further show that for fractional {\\it sLag} three-cycles, the compact geometry can be rewritten in a $(T^...
Bergshoeff, Eric A
2011-01-01
We show that the branes of ten-dimensional IIA/IIB string theory must satisfy, upon toroidal compactification, specific wrapping rules in order to reproduce the number of supersymmetric branes that follows from a supergravity analysis. The realization of these wrapping rules suggests that IIA/IIB string theory contains a whole class of generalized Kaluza-Klein monopoles.
Bergshoeff, E.; Riccioni, F.
2012-01-01
We show that the branes of ten-dimensional IA/IIB string theory must satisfy, upon toroidal compactification, specific wrapping rules in order to reproduce the number of supersymmetric branes that follows from a supergravity analysis. The realization of these wrapping rules suggests that IA/IIB stri
Brane-world cosmology with black strings
Gergely, L A
2006-01-01
We consider the simplest scenario when black strings (cigars) penetrate the cosmological brane. As a result, the brane has a Swiss-cheese structure, with Schwarzschild black holes immersed in a Friedmann-Lema\\^{\\i}tre-Robertson-Walker brane. There is no dark radiation in the model, the cosmological regions of the brane are characterized by a cosmological constant $\\Lambda$ and flat spatial sections. Regardless of the value of $\\Lambda$, these brane-world universes forever expand and forever decelerate. The totality of source terms in the modified Einstein equation sum up to a dust, establishing a formal equivalence with the general relativistic Einstein-Straus model. However in this brane-world scenario with black strings the evolution of the cosmological fluid strongly depends on $\\Lambda$. For $\\Lambda$ less or equal to zero it has positive energy density $\\rho$ and negative pressure $p$ and at late times it behaves as in the Einstein-Straus model. For (not too high) positive values of $\\Lambda$ the cosmolo...
Warped Brane worlds in Critical Gravity
Zhong, Yi; Chen, Feng-Wei; Xie, Qun-Ying
2014-01-01
We investigate the brane models in arbitrary dimensional critical gravity presented in [Phys. Rev. Lett. 106, 181302 (2011)]. For the model of the thin branes with codimension one, the Gibbons-Hawking surface term and the junction conditions are derived, with which the analytical solutions for the flat, AdS, and dS branes are obtained at the critical point of the critical gravity. It is found that all these branes are embedded in an AdS$_{n}$ spacetime, but, in general, the effective cosmological constant $\\Lambda$ of the AdS$_{n}$ spacetime is not equal to the naked one $\\Lambda_0$ in the critical gravity, which can be positive, zero, and negative. Another interesting result is that the brane tension can also be positive, zero, or negative, depending on the symmetry of the thin brane and the values of the parameters of the theory, which is very different from the case in general relativity. It is shown that the mass hierarchy problem can be solved in the higher-order braneworld model in the critical gravity....
D-branes and BCFT in Hpp-wave backgrounds
International Nuclear Information System (INIS)
In this paper we study two classes of symmetric D-branes in the Nappi-Witten gravitational wave, namely D2- and S1-branes. We solve the sewing constraints and determine the bulk-boundary couplings and the boundary three-point couplings. For the D2-brane our solution gives the first explicit results for the structure constants of the twisted symmetric branes in a WZW model. We also compute the boundary four-point functions, providing examples of open string four-point amplitudes in a curved background. We finally discuss the annulus amplitudes, the relation with branes in AdS3 and in S3 and the analogy between the open string couplings in the H4 model and the couplings for magnetized and intersecting branes
Reheating a multi-throat universe by brane motion
Mukohyama, Shinji
2007-01-01
We propose a mechanism of reheating after inflation in multi-throat scenarios of warped extra dimensions. Validity of the effective field theory requires that the position of the standard model (SM) brane during inflation be different from the position long after inflation, i.e. the tip of the SM throat. After inflation, when the Hubble expansion rate becomes sufficiently low, the SM brane starts moving towards the tip and eventually oscillates. The SM fields are excited by the brane motion and the universe is reheated. We consider a U(1) gauge field on a wrapped D5-brane as a toy model to illustrate that fields confined on a brane are indeed excited by brane motion.
Bare and effective fluid description in brane world cosmology
Energy Technology Data Exchange (ETDEWEB)
Cruz, Norman [Universidad de Santiago, Departamento de Fisica, Facultad de Ciencia, Casilla 307, Santiago (Chile); Lepe, Samuel; Saavedra, Joel [Pontificia Universidad Catolica de Valparaiso, Instituto de Fisica, Casilla 4950, Valparaiso (Chile); Pena, Francisco [Universidad de La Frontera, Departamento de Ciencias Fisicas, Facultad de Ingenieria, Ciencias y Administracion, Avda. Francisco Salazar 01145, Casilla 54-D, Temuco (Chile)
2010-03-15
An effective fluid description, for a brane world model in five dimensions, is discussed for both signs of the brane tension. We found several cosmological scenarios where the effective equation differs widely from the bare equation of state. For universes with negative brane tension, with a bare fluid satisfying the strong energy condition, the effective fluid can cross the barrier {omega} {sub eff}=-1. (orig.)
On the Production of Open Strings from Brane Anti-Brane Annihilation
Leblond, L
2006-01-01
We investigate the leading contribution to open string production in the time dependent background of the Brane Anti-Brane. This is a 1-loop diagram and we use Boundary Conformal Field Theory (BCFT) techniques to study it. We show that the amplitude to a single open string naively diverges when one looks at it as an expansion in oscillator levels. Nevertheless, we show that once we sum over all oscillator levels we get a finite result. We also clarify where to perform the inverse Wick rotation in this kind of problems. This calculation could have important consequences for the theory of reheating in brane inflationary models.
String and Brane Tensions as Dynamical Degrees of Freedom
Guendelman, E I; Nissimov, Emil R; Pacheva, S; Guendelman, Eduardo; Kaganovich, Alexander; Nissimov, Emil; Pacheva, Svetlana
2002-01-01
We discuss a new class of string and p-brane models where the string/brane tension appears as an additional dynamical degree of freedom instead of being introduced by hand as an ad hoc dimensionfull scale. The latter property turns out to have a significant impact on the string/brane dynamics. The dynamical tension obeys Maxwell (or Yang-Mills) equations of motion (in the string case) or their rank p gauge theory analogues (in the p-brane case), which in particular triggers a simple classical mechanism of (``color'') charge confinement.
Gibbons, G. W.
1999-05-01
A BIon may be defined as a finite energy solution of a nonlinear field theory with distributional sources. In contrast, a soliton is usually defined to have no sources. I show how harmonic coordinates map the exteriors of the topologically and causally non-trivial spacetimes of extreme p-branes to BIonic solutions of the Einstein equations in a topologically trivial spacetime in which the combined gravitational and matter energy-momentum is located on distributional sources. As a consequence the tension of BPS p-branes is classically unrenormalized. The result holds equally for spacetimes with singularities and for those, like the M-5-brane, which are everywhere singularity free.
Roberts, Mark D.
2015-10-01
Solutions are found to field equations constructed from the Pauli, Bach and Gauss-Bonnet quadratic tensors to the Kasner and Kasner brane spacetimes in up to five dimensions. A double Kasner space is shown to have a vacuum solution. Brane solutions in which the bulk components of the Einstein tensor vanish are also looked at and for four-branes a solution similar to radiation Robertson-Walker spacetime is found. Matter trapping of a test scalar field and a test perfect fluid are investigated using energy conditions.
Gibbons, G W
1999-01-01
A BIon may be defined as a finite energy solution of a non-linear field theory with distributional sources. By contrast a soliton is usually defined to have no sources. I show how harmonic coordinates map the exteriors of the topologically and causally non-trivial spacetimes of extreme p-branes to BIonic solutions of the Einstein equations in a topologically trivial spacetime in which the combined gravitational and matter energy momentum is located on distributional sources. As a consequence the tension of BPS p-branes is classically unrenormalized. The result holds equally for spacetimes with singularities and for those, like the M-5-brane, which are everywhere singularity free.
Medved, A J M
2002-01-01
The so-called ``brick-wall model'' is a semi-classical approach that has been used to explain black hole entropy in terms of thermal matter fields. Here, we apply the brick-wall formalism to thermal bulk fields in a Randall-Sundrum brane world scenario. In this case, the black hole entity is really a string-like object in the anti-de Sitter bulk, while appearing as a Schwarzchild black hole to observers living on the brane. In spite of these exotic circumstances, we establish that the Bekenstein-Hawking entropy law is preserved. Although a similar calculation was recently considered in the literature, this prior work invoked a simplifying assumption (which we avoid) that can not be adequately justified.
Energy Technology Data Exchange (ETDEWEB)
Medved, A J M [Department of Physics and Theoretical Physics Institute, University of Alberta, Edmonton (Canada)
2002-01-21
The so-called 'brick-wall model' is a semiclassical approach that has been used to explain black hole entropy in terms of thermal matter fields. Here, we apply the brick-wall formalism to thermal bulk fields in a Randall-Sundrum brane world scenario. In this case, the black hole entity is really a string-like object in the anti-de Sitter bulk, while appearing as a Schwarzchild black hole to observers living on the brane. In spite of these exotic circumstances, we establish that the Bekenstein-Hawking entropy law is preserved. Although a similar calculation was recently considered in the literature, this prior study invoked a simplifying assumption (which we avoid) that cannot be adequately justified.
Randall-Sundrum brane-world in modified gravity
Nakada, Hiroshi
2016-01-01
We modify Randall-Sundrum model of brane-world (with two branes) by adding the scalar curvature squared term in five dimensions. We find that it does not destabilize Randall-Sundrum solution to the hierarchy problem of the Standard Model in particle physics.
Thermodynamics of anisotropic branes
Ávila, Daniel; Patiño, Leonardo; Trancanelli, Diego
2016-01-01
We study the thermodynamics of flavor D7-branes embedded in an anisotropic black brane solution of type IIB supergravity. The flavor branes undergo a phase transition between a `Minkowski embedding', in which they lie outside of the horizon, and a `black hole embedding', in which they fall into the horizon. This transition depends on two independent dimensionless ratios, which are formed out of the black hole temperature, its anisotropy parameter, and the mass of the flavor degrees of freedom. It happens either at a critical temperature or at a critical anisotropy. A general lesson we learn from this analysis is that the anisotropy, in this particular realization, induces similar effects as the temperature. In particular, increasing the anisotropy bends the branes more and more into the horizon. Moreover, we observe that the transition becomes smoother for higher anisotropies.
Directory of Open Access Journals (Sweden)
Pablo Bueno
2015-04-01
Full Text Available We prove that for arbitrary black brane solutions of generic Supergravities there is an adapted system of variables in which the equations of motion are exactly invariant under electric–magnetic duality, i.e. the interchange of a given extended object by its electromagnetic dual. We obtain thus a procedure to automatically construct the electromagnetic dual of a given brane without needing to solve any further equation. We apply this procedure to construct the non-extremal (p,q-string of Type-IIB String Theory (new in the literature, explicitly showing how the dual (p,q-five-brane automatically arises in this construction. In addition, we prove that the system of variables used is suitable for a generic characterization of every double-extremal Supergravity brane solution, which we perform in full generality.
p-brane production in the fat brane or universal extra dimension scenario
International Nuclear Information System (INIS)
In models of large extra dimensions, the fundamental Planck scale can be as low as TeV. Thus, in hadronic collisions interesting objects such as black holes, string balls, or p-branes can be produced. In scenarios of a fat brane or universal extra dimensions, the standard model particles are allowed to propagate in the extra spatial dimensions, which leads to the enhancement of the production cross sections of black holes and p-branes. Especially, the ratio of the p-brane cross section to the black hole cross section increases substantially, in comparison with the original confined scenario. The ratio can be as large as 105 (for the case n=7,m=5=p=r=k)
Anomalies, Branes, and Currents
Cheung, Yeuk-Kwan E.; Yin, Zheng
1997-01-01
When a D-brane wraps around a cycle of a curved manifold, the twisting of its normal bundle can induce chiral asymmetry in its worldvolume theory. We obtain the general form of the resulting anomalies for D-branes and their intersections. They are not cancelled among themselves, and the standard inflow mechanism does not apply at first sight because of their apparent lack of factorizability and the apparent vanishing of the corresponding inflow. We show however after taking into consideration...
Myers, R C
1999-01-01
We extend the usual world-volume action for a Dp-brane to the case of N coincident Dp-branes where the world-volume theory involves a U(N) gauge theory. The guiding principle in our construction is that the action should be consistent with the familiar rules of T-duality. The resulting action involves a variety of potential terms, i.e., nonderivative interactions, for the nonabelian scalar fields. This action also shows that Dp-branes naturally couple to RR potentials of all form degrees, including both larger and smaller than p+1. We consider the dynamics resulting from this action for Dp-branes moving in nontrivial background fields, and illustrate how the Dp-branes are ``polarized'' by external fields. In a simple example, we show that a system of D0-branes in an external RR four-form field expands into a noncommutative two-sphere, which is interpreted as the formation of a spherical D2-D0 bound state.
New 3-Brane Solutions in 5D Spacetime
Midodashvili, Pavle
2010-01-01
In the article it is explicitly found new possible brane model solutions for the 5D spacetime physical set-up. These solutions require a ghost-like bulk scalar-field and the 3-brane at the origin of extra coordinate.
Regge-Teitelboim Goedetic Brane Gravity and Effective Cosmology
Naboulsi, R
2003-01-01
A geodetic brane cosmology formulated by virtue of 5-dimensional local isometric embedding is investigated with the context of Regge-Teitelboim brane gravity. We discuss a simple model where the resulting FRW evolution of the universe is governed by an effective density of the form rho + Lambda + 3m^2 where m is a constant having the dimension of the Hubble constant H.
Brane Structure from Scalar Field in Warped Spacetime
Bazeia, D; Gomes, A R
2004-01-01
We deal with scalar field coupled to gravity in five dimensions in warped geometry. We investigate models described by potentials that drive the system to support thick brane solutions that engender internal structure. We also show that the brane solutions simulate the occurrence of the complete wetting phenomenon at high temperatures.
p-brane production in Fat brane or Universal extra dimension scenario
Cheung, K; Cheung, Kingman; Chou, Chung-Hsien
2002-01-01
In models of large extra dimensions, the fundamental Planck scale can be as low as TeV. Thus, in hadronic collisions interesting objects like black holes, string balls, or $p$-branes can be produced. In scenarios of fat brane or universal extra dimensions, the SM particles are allowed to propagate in the extra spatial dimensions, which leads to the enhancement of production cross sections of black holes and $p$-branes. Especially, the ratio of $p$-brane cross section to the black hole cross section increases substantially, in comparison with the original confined scenario. The ratio can be as large as 105 (for the case $n=7,m=5=p=r=k$).
Gravitational backreaction of anti-D branes in the warped compactification
Koyama, Kayoko; Koyama, Kazuya
2005-09-01
We derive a low-energy effective theory for gravity with anti-D branes, which are essential to get de Sitter solutions in the type IIB string-warped compactification, by taking account of gravitational backreactions of anti-D branes. In order to see the effects of the self-gravity of anti-D branes, a simplified model is studied where a five-dimensional anti-de Sitter (AdS) spacetime is realized by the bulk cosmological constant and the 5-form flux, and anti-D branes are coupled to the 5-form field by Chern Simon terms. The AdS spacetime is truncated by introducing UV and IR cut-off branes like the Randall Sundrum model. We derive an effective theory for gravity on the UV brane and reproduce the familiar result that the tensions of the anti-D branes give potentials suppressed by the fourth power of the warp factor at the location of the anti-D branes. However, in this simplified model, the potential energy never inflates the UV brane, although the anti-D branes are inflating. The UV brane is dominated by dark radiation coming from the projection of the five-dimensional Weyl tensor, unless the moduli fields for the anti-D branes are stabilized. We comment on the possibility of avoiding this problem in a realistic string theory compactification.
Cosmology of brane universes and brane gases
Boehm, Timon Georg; Durrer, Ruth
2004-01-01
Nous étudions le comportement dynamique et perturbateur de certains modèles cosmologiques inspirés par la théorie des cordes. Celle-ci est une théorie de la gravité quantique qui est fort probablement nécessaire pour comprendre l'origine de notre univers. Ses prédictions (l'existence des dimensions supplémentaires et des p-branes) sont très intéressantes pour la cosmologie. D'abord, notre univers est identifié avec une 3-brane plongée dans un espace-temps cinq-dimensionnel. Nous montrons que ...
Cosmology of brane universes and brane gases
Boehm, Timon Georg
2003-01-01
Nous étudions le comportement dynamique et perturbateur de certains modèles cosmologiques inspirés par la théorie des cordes. Celle-ci est une théorie de la gravité quantique qui est fort probablement nécessaire pour comprendre l'origine de notre univers. Ses prédictions (l'existence des dimensions supplémentaires et des p-branes) sont très intéressantes pour la cosmologie. D'abord, notre univers est identifié avec une 3-brane plongée dans un espace-temps cinq-dimensionnel. Nous montrons que ...
T-branes and $\\alpha'$-corrections
Marchesano, Fernando
2016-01-01
We study $\\alpha'$-corrections in multiple D7-brane configurations with non-commuting profiles for their transverse position fields. We focus on T-brane systems, crucial in F-theory GUT model building. There $\\alpha'$-corrections modify the D-term piece of the BPS equations which, already at leading order, require a non-primitive Abelian worldvolume flux background. We find that $\\alpha'$-corrections may either i) leave this flux background invariant, ii) modify the Abelian non-primitive flux profile, or iii) deform it to a non-Abelian profile. The last case typically occurs when primitive fluxes, a necessary ingredient to build 4d chiral models, are added to the system. We illustrate these three cases by solving the $\\alpha'$-corrected D-term equations in explicit examples, and describe their appearance in more general T-brane backgrounds. Finally, we discuss implications of our findings for F-theory GUT local models.
Thick Brane Worlds Arising From Pure Geometry
Cardenas, R; Cardenas, Rolando; Quiros, Israel
2002-01-01
We study a non-Riemannian modification of 5-dimensional Kaluza-Klein theory. In our proposal the Riemannian structure of the five-dimensional manifold is replaced by a Weyl-integrable one. In this context a 4-dimensional Poincar$\\grave{e}$ invariant solution is studied. A spacetime structure with two thick (smooth) branes separated in the extra dimension arises. The massless graviton is located in one of the thick branes at the origin, meanwhile the matter degrees of freedom are confined to the other brane. Due to the small overlap of the graviton's wave-function with the second thick brane, the model accounts for a resolution of the mass hierarchy problem a la Randall-Sundrum. Although, initially, no assumptions are made about the topology of the extra dimension, the solution found yields an extra space that is effectivelly compact and respects $Z_2$ symmetry. Unlike other models with branes, the spectrum of massive Kaluza-Klein states is quantized and free of tachyonic modes.
Multiple M0-brane equations in eleven dimensional pp-wave superspace and BMN matrix model
Bandos, Igor A.
2012-01-01
We obtain the Matrix model equations in the background of the maximally supersymmetric pp-wave solution of the 11D supergravity and discuss its relation with the Berenstein-Maldacena-Nastase (BMN) model.
Hybrid metric-Palatini brane system
Fu, Qi-Ming; Zhao, Li; Gu, Bao-Min; Yang, Ke; Liu, Yu-Xiao
2016-07-01
It is known that the metric and Palatini formalisms of gravity theories have their own interesting features but also suffer from some different drawbacks. Recently, a novel gravity theory called hybrid metric-Palatini gravity was put forward to cure or improve their individual deficiencies. The action of this gravity theory is a hybrid combination of the usual Einstein-Hilbert action and a f (R ) term constructed by the Palatini formalism. Interestingly, it seems that the existence of a light and long-range scalar field in this gravity may modify the cosmological and galactic dynamics without conflicting with the laboratory and Solar System tests. In this paper, we focus on the tensor and scalar perturbations of the thick branes in this novel gravity theory. We consider two models as examples, namely, the thick branes constructed by a background scalar field and by pure gravity. The thick branes in both models have no inner structure. However, affected by the hybrid combination of the metric and Palatini formalisms, the graviton zero mode in the first model has inner structure when the parameter in this model is larger than its critical value, which is different from the cases of general relativity and Palatini f (R ) gravity. We find that the effective four-dimensional gravity can be reproduced on the brane for both models and the scalar zero mode in the model without a background scalar field cannot be localized on the brane, which avoids a fifth force. Moreover, the stability of both brane systems against the linear perturbations can also be ensured.
Brane Webs and Random Processes
Iqbal, Amer; Shabbir, Khurram; Shehper, Muhammad A
2015-01-01
We study $(p,q)$ 5-brane webs dual to certain $N$ M5-brane configurations and show that the partition function of these brane webs gives rise to cylindric Schur process with period $N$. This generalizes the previously studied case of period $1$. We also show that open string amplitudes corresponding to these brane webs are captured by the generating function of cylindric plane partitions with profile determined by the boundary conditions imposed on the open string amplitudes.
Nernst branes in gauged supergravity
Barisch, Susanne; Haack, Michael; Nampuri, Suresh; Obers, Niels A
2011-01-01
We study static black brane solutions in the context of N = 2 U(1) gauged supergravity in four dimensions. Using the formalism of first-order flow equations, we construct novel extremal black brane solutions including examples of Nernst branes, i.e. extremal black brane solutions with vanishing entropy density. We also discuss a class of non-extremal generalizations which is captured by the first-order formalism.
Localized gravity on FRW branes
Singh, Parampreet; Dadhich, Naresh
2002-01-01
We study the system of Schwarzschild anti de Sitter (S-AdS) bulk and FRW brane for localization of gravity; i.e. zero mass gravitons having ground state on the brane, and thereby recovering the Einstein gravity with high energy correction. It has been known that gravity is not localized on AdS brane with AdS bulk. We prove the general result that gravity is not localized for dynamic branes whenever Lambda_4 0 and black h...
Brane cosmology in teleparallel gravity
Atazadeh, K
2014-01-01
We consider cosmology of brane-world scenario in the frame work of teleparallel gravity in that way matter is localized on the brane. We show that the cosmology of such branes is different from the standard cosmology in teleparallelism. In particular, we obtain a class of new solutions with a constant five-dimensional radius and cosmologically evolving brane in the context of constant torsion $f(T)$ gravity.
Supergravity Induced Interactions on Thick Branes
Yilmaz, Nejat Tevfik
2014-01-01
The gravity coupling of the symmetric space sigma model is studied in the solvable Lie algebra parametrization. The corresponding Einstein's equations are derived and the energy-momentum tensor is calculated. The results are used to derive the dynamical equations of the warped 5D geometry for localized bulk scalar interactions in the framework of thick brane world models. The Einstein and scalar field equations are derived for flat brane geometry in the context of minimal and non-minimal gravity-bulk scalar couplings.
Asymmetric Swiss-cheese brane-worlds
Gergely, László Á.; Képíró, Ibolya
2007-07-01
We study a brane-world cosmological scenario with local inhomogeneities represented by black holes. The brane is asymmetrically embedded into the bulk. The black strings/cigars penetrating the Friedmann brane generate a Swiss-cheese-type structure. This universe forever expands and decelerates, as its general relativistic analogue. The evolution of the cosmological fluid, however, can proceed along four branches, two allowed to have positive energy density, and one of them having the symmetric embedding limit. On this branch a future pressure singularity can arise for either (a) a difference in the cosmological constants of the cosmological and black hole brane regions or (b) a difference in the left and right bulk cosmological constants. While behaviour (a) can be avoided by a redefinition of the fluid variables, (b) establishes a critical value of the asymmetry over which the pressure singularity occurs. We introduce the pressure singularity censorship which bounds the degree of asymmetry in the bulk cosmological constant. We also show as a model-independent generic feature that the asymmetry source term due to the bulk cosmological constant increases in the early universe. In order to obey the nucleosynthesis constraints, the brane tension should be constrained therefore both from below and from above. With the maximal degree of asymmetry obeying the pressure singularity censorship, the higher limit is ten times the lower limit. The degree of asymmetry allowed by present cosmological observations is, however, much less, pushing the upper limit to infinity.
Emergence and expansion of cosmic space as due to M0-branes
Energy Technology Data Exchange (ETDEWEB)
Sepehri, Alireza, E-mail: alireza.sepehri@uk.ac.ir [Faculty of Physics, Shahid Bahonar University, P.O. Box 76175, Kerman (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha (Iran, Islamic Republic of); Setare, Mohammad Reza, E-mail: rezakord@ipm.ir [Department of Science, University of Kurdistan, Campus of Bijar, Bijar (Iran, Islamic Republic of); Capozziello, Salvatore, E-mail: capozziello@na.infn.it [Dipartimento di Fisica, Universita di Napoli Federico II, 80126, Naples (Italy); INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, 80126, Naples (Italy); Gran Sasso Science Institute (INFN), Viale F. Crispi, 7, 67100, L’Aquila (Italy)
2015-12-29
Recently, Padmanabhan discussed that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region causes the accelerated expansion of the universe. The main question arising is: what is the origin of this inequality between the surface degrees of freedom and the bulk degrees of freedom? We answer this question in M-theory. In our model, first M0-branes are compactified on one circle and ND0-branes are created. Then ND0-branes join each other, grow, and form one D5-branes. Next, the D5-brane is compactified on two circles and our universe’s D3-brane, two D1-branes and some extra energies are produced. After that, one of the D1-branes, which is closer to the universe’s brane, gives its energy into it, and this leads to an increase in the difference between the numbers of degrees of freedom and the occurring inflation era. With the disappearance of this D1-brane, the number of degrees of freedom of boundary surface and bulk region become equal and inflation ends. At this stage, extra energies that are produced due to the compactification cause an expansion of the universe and deceleration epoch. Finally, another D1-brane dissolves in our universe’s brane, leads to an inequality between degrees of freedom, and there occurs a new phase of acceleration.
Energy Technology Data Exchange (ETDEWEB)
McGreevy, John Austen; /Stanford U., Phys. Dept.
2005-07-06
This thesis is a study of D-branes in string compactifications. In this context, D-branes are relevant as an important component of the nonperturbative spectrum, as an incisive probe of these backgrounds, and as a natural stringy tool for localizing gauge interactions. In the first part of the thesis, we discuss half-BPS D-branes in compactifications of type II string theory on Calabi-Yau threefolds. The results we describe for these objects are pertinent both in their role as stringy brane-worlds, and in their role as solitonic objects. In particular, we determine couplings of these branes to the moduli determining the closed-string geometry, both perturbatively and non-perturbatively in the worldsheet expansion. We provide a local model for transitions in moduli space where the BPS spectrum jumps, and discuss the extension of mirror symmetry between Calabi-Yau manifolds to the case when D-branes are present. The next section is an interlude which provides some applications of D-branes to other curved backgrounds of string theory. In particular, we discuss a surprising phenomenon in which fundamental strings moving through background Ramond-Ramond fields dissolve into large spherical D3-branes. This mechanism is used to explain a previously-mysterious fact discovered via the AdS-CFT correspondence. Next, we make a connection between type IIA string vacua of the type discussed in the first section and M-theory compactifications on manifolds of G{sub 2} holonomy. Finally we discuss constructions of string vacua which do not have large radius limits. In the final part of the thesis, we develop techniques for studying the worldsheets of open strings ending on the curved D-branes studied in the first section. More precisely, we formulate a large class of massive two-dimensional gauge theories coupled to boundary matter, which flow in the infrared to the relevant boundary conformal field theories. Along with many other applications, these techniques are used to describe
Mirror symmetry in the presence of branes
Energy Technology Data Exchange (ETDEWEB)
Mertens, Adrian
2011-10-11
This work deals with mirror symmetry for N=1 compactifications on compact Calabi-Yau threefolds with branes. The mayor tool is a combined deformation space for the Calabi-Yau and a hypersurface within it. Periods of this deformation space contain information about B-type branes within the hypersurface in addition to the usual closed string data. To study these periods we generalize techniques used in closed string mirror symmetry. We derive the Picard-Fuchs system and encode the information in extended toric polytopes. Solutions of the Picard-Fuchs equations give superpotentials for certain brane configurations. This is an efficient way to calculate superpotentials. The deformations we consider are massive for all branes with non trivial superpotential. Depending on a choice of a family of hypersurfaces, the superpotential of the effective low energy theory depends on different massive fields. A priori there is no reason for these fields to be lighter then other fields that are not included. We find however examples where the superpotential is nearly at. In these examples we use the Gauss-Manin connection on the combined deformation space to define an open string mirror map. We find instanton generated superpotentials of A-type branes. This gives predictions for Ooguri-Vafa invariants counting holomorphic disks that end on a Lagrangian brane on the Quintic. A second class of examples does not have preferred nearly massless deformations and different families of hypersurfaces can be used to calculate the same on-shell superpotential. We calculate examples of superpotentials for branes in Calabi-Yau manifolds with several moduli. The on-shell superpotentials are mapped to the mirror A-model to study the instanton expansion and to obtain predictions for disk invariants. The combined deformation spaces are equivalent to the quantum corrected Kaehler deformation spaces of certain non compact Calabi-Yau fourfolds. These fourfolds are fibrations of Calabi-Yau threefolds
Karasik, D; Karasik, David; Davidson, Aharon
2003-01-01
Geodetic brane gravity treats the universe as an extended object evolving geodetically within a higher dimensional flat background. In this paper we derive the quadratic Hamiltonian of the brane by introducing a new pair of canonical fields $\\lambda,P_{\\lambda}$. This causes second class constraints to enter the game, and calls for the use of Dirac Brackets. The algebra of first class constraints is calculated, and the BRST generator of the brane universe is of rank 1. The Einstein case, associated with $\\lambda$ being a vanishing (degenerate) eigenvalue, can be treated only as a limiting case. At the quantum level, the road is open for canonical quantization, or functional integral quantization. The main advantages of GBG are: It contains an intrinsic, geometrically originated 'dark matter' components. It contains an intrinsic solution to the 'problem of time' with the aid of the 'bulk' time coordinate. It enables calculation of meaningful probabilities within quantum cosmology without any additional scalar ...
D-brane Instantons in Type II String Theory
Energy Technology Data Exchange (ETDEWEB)
Blumenhagen, Ralph; /Munich, Max Planck Inst.; Cvetic, Mirjam; /Pennsylvania U.; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC; Weigand, Timo; /SLAC
2009-06-19
We review recent progress in determining the effects of D-brane instantons in N=1 supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract D-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function and higher fermionic F-terms. This includes a discussion of multi-instanton effects and the implications of background fluxes for the instanton sector. Our presentation also highlights, but is not restricted to the computation of D-brane instanton effects in quiver gauge theories on D-branes at singularities. We then summarize the concrete consequences of stringy D-brane instantons for the construction of semi-realistic models of particle physics or SUSY-breaking in compact and non-compact geometries.
Matter localization on brane-worlds generated by deformed defects
Bernardini, Alex E
2016-01-01
Localization and mass spectrum of bosonic and fermionic matter fields of some novel families of asymmetric thick brane configurations generated by deformed defects are investigated. The localization profiles of spin 0, spin 1/2 and spin 1 bulk fields are identified for novel matter field potentials supported by thick branes with internal structures. The condition for localization is constrained by the brane thickness of each model such that thickest branes strongly induces matter localization. The bulk mass terms for both fermion and boson fields are included in the global action as to produce some imprints on mass-independent potentials of the Kaluza-Klein modes associated to the corresponding Schr\\"odinger equations. In particular, for spin 1/2 fermions, a complete analytical profile of localization is obtained for the four classes of superpotentials here discussed. Regarding the localization of fermion fields, our overall conclusion indicates that thick branes produce a left-right asymmetric chiral localiz...
D-brane Instantons in Type II String Theory
Blumenhagen, Ralph; Kachru, Shamit; Weigand, Timo
2009-01-01
We review recent progress in determining the effects of D-brane instantons in N=1 supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract D-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function and higher fermionic F-terms. This includes a discussion of multi-instanton effects and the implications of background fluxes for the instanton sector. Our presentation also highlights, but is not restricted to the computation of D-brane instanton effects in quiver gauge theories on D-branes at singularities. We then summarize the concrete consequences of stringy D-brane instantons for the construction of semi-realistic models of particle physics or SUSY-breaking in compact and non-compact geometries.
Extra-dimensional cosmology with domain-wall branes
International Nuclear Information System (INIS)
We show how to define a consistent braneworld cosmology in a model in which the brane is constructed as a field-theoretic domain wall of finite thickness. The Friedmann, Robertson-Walker metric is recovered in the region of the brane, but, remarkably, with scale factor that depends on particle energy and on particle species, constituting a breakdown of the weak equivalence principle on sufficiently small scales. This unusual effect comes from the extended nature of particles confined to a domain-wall brane, and the fact that they feel an 'average' of the bulk spacetime. We demonstrate how to recover the standard results of brane cosmology in the infinitely-thin brane limit, and comment on how our results have the potential to place bounds on parameters such as the thickness of domain-wall braneworlds.
Toward the stabilization of extra dimensions by brane dynamics
Kitazawa, Noriaki
2015-04-01
All the models of elementary particles and their interactions derived from String Theory involve a compact six-dimensional internal space. Its volume and shape should be fixed or stabilized, since otherwise massless scalar fields (moduli) reflecting their deformations appear in our four-dimensional space-time, with sizable effects on known particles and fields. We propose a strategy toward stabilizing the compact space without fluxes of three-form fields from closed strings. Our main motivation and goal is to proceed insofar as possible within conventional string worldsheet theory. As we shall see, D-branes with magnetic flux ("magnetized D-branes") and the forces between them can be used to this end. We investigate here some necessary ingredients: open string one-loop vacuum amplitudes between magnetized D-branes, magnetized D-branes fixed at orbifold singularities, and potential energies among such D-branes in the compact space that result from tree-level closed string exchanges.
A varying-α brane world cosmology
International Nuclear Information System (INIS)
We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)
D6-Brane Model Building on Z(2)xZ(6): MSSM-like and Left-Right Symmetric Models
Ecker, Jill; Staessens, Wieland
2015-01-01
We perform a systematic search for globally defined MSSM-like and left-right symmetric models on D6-branes on the T6/Z(2)xZ(6)xOR orientifold with discrete torsion. Our search is exhaustive for models that are independent of the value of the one free complex structure modulus. Preliminary investigations suggest that there exists one prototype of visible sector for MSSM-like and another for left-right symmetric models with differences arising from various hidden sector completions to global models. For each prototype, we provide the full matter spectrum, as well as the Yukawa and other three-point couplings needed to render vector-like matter states massive. This provides us with tentative explanations for the mass hierarchies within the quark and lepton sectors. We also observe that the MSSM-like models correspond to explicit realisations of the supersymmetric DFSZ axion model, and that the left-right symmetric models allow for global completions with either completely decoupled hidden sectors or with some me...
Brane Inflation and the Overshoot Problem
Bird, Simeon; Baumann, Daniel
2009-01-01
We investigate recent claims that brane inflation solves the overshoot problem through a combination of microphysical restrictions on the phase space of initial conditions and the existence of the Dirac-Born-Infeld (DBI) attractor in regimes where the slow-roll attractor does not apply. Carrying out a comprehensive analysis of the parameter space allowed by the latest advances in brane inflation model-building, we find that these restrictions are insufficient to solve the overshoot problem. The vast majority of the phase space of initial conditions is still dominated by overshoot trajectories. We present an analytic proof that the brane-inflationary attractor must be close to the slow-roll limit, and update the predictions for observables such as non-Gaussianity, cosmic string tension and tensor modes.
Domain wall brane in squared curvature gravity
Liu, Yu-Xiao; Zhao, Zhen-Hua; Li, Hai-Tao
2011-01-01
We suggest a thick braneworld model in the squared curvature gravity theory. Despite the appearance of higher order derivatives, the localization of gravity and various bulk matter fields is shown to be possible. The existence of the normalizable gravitational zero mode indicates that our four-dimensional gravity is reproduced. In order to localize the chiral fermions on the brane, two types of coupling between the fermions and the brane forming scalar is introduced. The first coupling leads us to a Schr\\"odinger equation with a volcano potential, and the other a P\\"oschl-Teller potential. In both cases, the zero mode exists only for the left-hand fermions. Several massive KK states of the fermions can be trapped on the brane, either as resonant states or as bound states.
Townsend, P.K.
1995-01-01
The ten or eleven dimensional origin of central charges in the N=4 or N=8 supersymmetry algebra in four dimensions is reviewed: while some have a standard Kaluza-Klein interpretation as momenta in compact dimensions, most arise from $p$-form charges in the higher-dimensional supersymmetry algebra that are carried by $p$-brane `solitons'. Although $p=1$ is singled out by superstring perturbation theory, U-duality of N=8 superstring compactifications implies a complete `$p$-brane democracy' of ...
Branes, Charge and Intersections
Marolf, D M
2001-01-01
This is a brief summary of lectures given at the Fourth Mexican School on Gravitation and Mathematical Physics. The lectures gave an introduction to branes in eleven-dimensional supergravity and in type IIA supergravities in ten-dimensions. Charge conservation and the role of the so-called `Chern-Simons terms' were emphasized. Known exact solutions were discussed and used to provide insight into the question `Why don't fundamental strings fall off of D-branes,' which is often asked by relativists. The following is a brief overview of the lectures with an associated guide to the literature.
Hair-brane Ideas on the Horizon
Martinec, Emil J
2015-01-01
We continue an examination of the microstate geometries program begun in arXiv:1409.6017, focussing on the role of branes that wrap the cycles which degenerate when a throat in the geometry deepens and a horizon forms. An associated quiver quantum mechanical model of minimally wrapped branes exhibits a non-negligible fraction of the gravitational entropy, which scales correctly as a function of the charges. The results suggest a picture of AdS_3/CFT_2 duality wherein the long string that accounts for BTZ black hole entropy in the CFT description, can also be seen to inhabit the horizon of BPS black holes on the gravity side.
Large N QCD from rotating branes
International Nuclear Information System (INIS)
We study large N SU(N) Yang-Mills theory in three and four dimensions using a one-parameter family of supergravity models which originate from non-extremal rotating D-branes. We show explicitly that varying this 'angular momentum' parameter decouples the Kaluza-Klein modes associated with the compact D-brane coordinate, while the mass ratios for ordinary glueballs are quite stable against this variation, and are in good agreement with the latest lattice results. We also compute the topological susceptibility and the gluon condensate as a function of the 'angular momentum' parameter. copyright 1999 The American Physical Society
Graviton Kaluza-Klein modes in nonflat branes with stabilized modulus
Paul, Tanmoy; SenGupta, Soumitra
2016-04-01
We consider a generalized two brane Randall-Sundrum model where the branes are endowed with nonzero cosmological constant. In this scenario, we re-examine the modulus stabilization mechanism and the nature of Kaluza-Klein (KK) graviton modes. Our result reveals that while the KK mode graviton masses may change significantly with the brane cosmological constant, the Goldberger-Wise stabilization mechanism, which assumes a negligible backreaction on the background metric, continues to hold even when the branes have a large cosmological constant. The possibility of having a global minimum for the modulus is also discussed. Our results also include an analysis for the radion mass in this nonflat brane scenario.
Brane Bremsstrahlung in DBI Inflation
Brax, Philippe
2010-01-01
We consider the effect of trapped branes on the evolution of a test brane whose motion generates DBI inflation along a warped throat. The coupling between the inflationary brane and a trapped brane leads to the radiation of non-thermal particles on the trapped brane. We calculate the Gaussian spectrum of the radiated particles and their backreaction on the DBI motion of the inflationary brane. Radiation occurs for momenta lower than the speed of the test brane when crossing the trapped brane. The slowing down effect is either due to a parametric resonance when the interaction time is small compared to the Hubble time or a tachyonic resonance when the interaction time is large. In both cases the motion of the inflationary brane after the interaction is governed by a chameleonic potential,which tends to slow it down. We find that a single trapped brane can hardly slow down a DBI inflaton whose fluctuations lead to the Cosmic Microwave Background spectrum. A more drastic effect is obtained when the DBI brane enc...
2d (0,2) Quiver Gauge Theories and D-Branes
Franco, Sebastian; Lee, Sangmin; Seong, Rak-Kyeong; Yokoyama, Daisuke
2015-01-01
We initiate a systematic study of 2d (0,2) quiver gauge theories on the worldvolume of D1-branes probing singular toric Calabi-Yau 4-folds. We present an algorithm for efficiently calculating the classical mesonic moduli spaces of these theories, which correspond to the probed geometries. We also introduce a systematic procedure for constructing the gauge theories for arbitrary toric singularities by means of partial resolution, which translates to higgsing in the field theory. Finally, we introduce Brane Brick Models, a novel class of brane configurations that consist of D4-branes suspended from an NS5-brane wrapping a holomorphic surface, tessellating a 3-torus. Brane Brick Models are the 2d analogues of Brane Tilings and allow a direct connection between geometry and gauge theory.
Finite Temperature Corrections to Tachyon Mass in Intersecting D-Branes
Sethi, Varun; Sarkar, Swarnendu
2016-01-01
We continue with the analysis of finite temperature corrections to the Tachyon mass in intersecting branes which was initiated in arxiv:1403.0389. In this paper we extend the computation to the case of intersecting D3-branes by considering a setup of two intersecting branes in flat-space background. A holographic model dual to BCS superconductor consisting of intersecting D8-branes in D4-brane background was proposed in arxiv:1104.2843. The background considered here is a simplified configuration of this dual model. We compute the one-loop Tachyon amplitude in the Yang-Mills approximation and show that the result is finite. Analyzing the amplitudes further we numerically compute the transition temperature at which the Tachyon becomes massless. The analytic expressions for the one-loop amplitudes obtained here reduce to those for intersecting D1-branes obtained in arxiv:1403.0389 as well as those for intersecting D2-branes.
M5-brane in three-form flux and multiple M2-branes
Ho, Pei-Ming; Matsuo, Yutaka; Shiba, Shotaro
2008-01-01
We investigate the Bagger-Lambert-Gustavsson model associated with the Nambu-Poisson algebra as a theory describing a single M5-brane. We argue that the model is a gauge theory associated with the volume-preserving diffeomorphism in the three-dimenisonal internal space. We derive gauge transformations, actions, supersymmetry transformations, and equations of motions in terms of six-dimensional fields. The equations of motions are written in gauge-covariant form, and the equations for tensor fields have manifest self-dual structure. We demonstrate that the double dimensional reduction of the model reproduces the non-commutative U(1) gauge theory on a D4-brane with a small non-commutativity parameter. We establish relations between parameters in the BLG model and those in M-theory. This shows that the model describes an M5-brane in a large C-field background.
Brane polarization is no cure for tachyons
Bena, Iosif
2015-01-01
Anti-M2 and anti-D3 branes placed in regions with charges dissolved in fluxes have a tachyon in their near-horizon region, which causes these branes to repel each other. If the branes are on the Coulomb branch this tachyon gives rise to a runaway behavior, but when the branes are polarized into five-branes this tachyon only appears to lower the energy of the polarized branes, without affecting its stability. We analyze brane polarization in the presence of a brane-brane-repelling tachyon and show that when the branes are polarized along the direction of the tachyon the polarized shell is unstable. This implies that tachyons cannot be cured by brane polarization and indicates that, at least in a certain regime of parameters, anti-D3 branes polarized into NS5 branes at the bottom of the Klebanov-Strassler solution have an instability.
Brane content of branes' states
Energy Technology Data Exchange (ETDEWEB)
Mkrtchyan, Ruben
2003-04-17
The problem of decomposition of unitary irreps of (super)tensorial (i.e., extended with tensorial charges) Poincare algebra w.r.t. its different subalgebras is considered. This requires calculation of little groups for different configurations of tensor charges. Particularly, for preon states (i.e., states with maximal supersymmetry) in different dimensions the particle content is calculated, i.e., the spectrum of usual Poincare representations in the preon representation of tensorial Poincare. At d=4 results coincide with (and may provide another point of view on) the Vasiliev's results in field theories in generalized space-time. The translational subgroup of little groups of massless particles and branes is shown to be (and coincide with, at d=4) a subgroup of little groups of 'pure branes' algebras, i.e., tensorial Poincare algebras without vector generators. At 11d it is shown that, contrary to lower dimensions, spinors are not homogeneous space of Lorentz group, and one have to distinguish at least 7 different kinds of preons.
Energy Technology Data Exchange (ETDEWEB)
Howe, P.S.; Kaya, A.; Sezgin, E.; Sundell, P
2000-10-30
We study codimension one branes, i.e., p-branes in (p+2) dimensions, in the superembedding approach for the cases where the worldvolume superspace is embedded in a minimal target superspace with half supersymmetry breaking. This singles out the cases p=1,2,3,5,9 . For p=3,5,9 the superembedding geometry naturally involves a fundamental super 2 -form potential on the worldvolume whose generalised field strength obeys a constraint deducible from considering an open supermembrane ending on the p -brane. This constraint, together with the embedding constraint, puts the system on-shell for p=5 but overconstrains the 9 -brane in D=11 such that the Goldstone superfield is frozen. For p=3 these two constraints give rise to an off-shell linear multiplet on the worldvolume. An alternative formulation of this case is given in which the linear multiplet is dualised to an off-shell scalar multiplet. Actions are constructed for both cases and are shown to give equivalent equations of motion. After gauge fixing a local Sp(1) symmetry associated with shifts in the Sp(1){sub R} Goldstone modes, we find that the auxiliary fields in the scalar multiplet parametrise a two-sphere. For completeness we also discuss briefly the cases p=1,2 where the equations of motion (for off-shell multiplets) are obtained from an action principle.
Ashour, Amani; Ali, Ahmed Farag; Hammad, Fayçal
2016-01-01
In this work, we investigate the thermodynamics of black $p$-branes (BB) in the context of Gravity's Rainbow. We investigate this, first within the framework of rainbow functions that have been proposed by Amelino-Camelia, et el. in \\cite{amerev, AmelinoCamelia:1996pj}, then examine, for the sake of comparison, a couple of other rainbow functions that have also appeared in the literature. We show that, for consistency, Rainbow Gravity imposes a constraint on the minimum mass of the BB, a constraint that we interpret here as implying the existence of a black $p$-brane remnant. This interpretation is supported by the computation of the black $p$-brane's heat capacity that shows that the latter vanishes when the Schwarzschild radius takes on a value that is bigger than its extremal limit. We found that the same conclusion is reached for the third version of rainbow functions treated here but not with the second one for which only standard black $p$-brane thermodynamics is recovered.
Ashour, Amani; Faizal, Mir; Ali, Ahmed Farag; Hammad, Fayçal
2016-05-01
In this work, we investigate the thermodynamics of black p-branes (BB) in the context of Gravity's Rainbow. We investigate this using rainbow functions that have been motivated from loop quantum gravity and κ -Minkowski non-commutative spacetime. Then for the sake of comparison, we examine a couple of other rainbow functions that have also appeared in the literature. We show that, for consistency, Gravity's Rainbow imposes a constraint on the minimum mass of the BB, a constraint that we interpret here as implying the existence of a black p-brane remnant. This interpretation is supported by the computation of the black p-brane's heat capacity that shows that the latter vanishes when the Schwarzschild radius takes on a value that is bigger than its extremal limit. We found that the same conclusion is reached for the third version of rainbow functions treated here but not with the second one for which only standard black p-brane thermodynamics is recovered.
Wave function of the radion in a brane world
Charmousis, Christos; Gregory, Ruth; Rubakov, Valery A.
1999-01-01
We calculate the linearized metric perturbation corresponding to a massless four-dimensional scalar field, the radion, in a five-dimensional two-brane model of Randall and Sundrum. In this way we obtain relative strengths of the radion couplings to matter residing on each of the branes. The results are in agreement with the analysis of Garriga and Tanaka of gravitational and Brans--Dicke forces between matter on the branes. We also introduce a model with infinite fifth dimension and ``almost'...
Tensor Perturbations from Brane-World Inflation with Curvature Effects
Bouhmadi-Lopez, Mariam; Liu, Yen-Wei; IZUMI, KEISUKE; Chen, Pisin(Graduate Institute of Astrophysics, National Taiwan University, Taipei, 10617, Taiwan)
2013-01-01
The brane-world scenario provides an intriguing possibility to explore the phenomenological cosmology implied by string/M theory. In this paper, we consider a modified Randall-Sundrum single brane model with two natural generalizations: a Gauss-Bonnet term in the five-dimensional bulk action as well as an induced gravity term in the four-dimensional brane action, which are the leading-order corrections to the Randall-Sundrum model. We study the influence of these combined effects on the evolu...
A Gauged Open 2-brane String in the p-brane Background
Sarvi, Fahimeh; Nejad, Salman Abarghouei
2015-01-01
In this article, we make a gauge theory from the Open p-brane system and map it into the Open 2-brane one. Due to the presence of second class constraints in this model, we encounter some problems during the procedure of quantization. In this regard, considering boundary conditions as Dirac conditions, one can drive the constrained structure of the model at first. Then, with the help of BFT formalism of constraint systems, the Open 2-brane model is embedded into an extended phase space. For this purpose, we introduce some tensor fields to convert ungauged theory into the gauged one. This is the novel part of our research, while mostly scalar and vector fields are used to convert second class constraints into first ones.
Deforming D-brane models on T{sup 6}/(Z{sub 2} x Z{sub 2M}) orbifolds
Energy Technology Data Exchange (ETDEWEB)
Koltermann, Isabel; Blaszczyk, Michael; Honecker, Gabriele [PRISMA Cluster of Excellence and Institut fuer Physik (WA THEP), Johannes-Gutenberg-Universitaet, Mainz (Germany)
2016-04-15
We review the stabilisation of complex structure moduli in Type IIA orientifolds, especially on T{sup 6}/(Z{sub 2} x Z{sub 6}{sup '} x ΩR) with discrete torsion, via deformations of Z{sub 2} x Z{sub 2} orbifold singularities. While D6-branes in SO(2N) and USp(2N) models always preserve supersymmetry and thus give rise to flat directions, in an exemplary Pati-Salam model with only U(N) gauge groups ten out of the 15 deformation moduli can be stabilised at the orbifold point. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Superconformal Quantum Mechanics from M2-branes
Okazaki, Tadashi
2015-01-01
We discuss the superconformal quantum mechanics arising from the M2-branes. We begin with a comprehensive review on the superconformal quantum mechanics and emphasize that conformal symmetry and supersymmetry in quantum mechanics contain a number of exotic and enlightening properties which do not occur in higher dimensional field theories. We see that superfield and superspace formalism is available for $\\mathcal{N}\\le 8$ superconformal mechanical models. We then discuss the M2-branes with a focus on the world-volume descriptions of the multiple M2-branes which are superconformal three-dimensional Chern-Simons matter theories. Finally we argue that the two topics are connected in M-theoretical construction by considering the multiple M2-branes wrapped around a compact Riemann surface and study the emerging IR quantum mechanics. We establish that the resulting quantum mechanics realizes a set of novel $\\mathcal{N}\\ge 8$ superconformal quantum mechanical models which have not been reached so far. Also we discus...
D-brane Deconstructions in IIB Orientifolds
Collinucci, Andres; Esole, Mboyo
2009-01-01
With model building applications in mind, we collect and develop basic techniques to analyze the landscape of D7-branes in type IIB compact Calabi-Yau orientifolds, in three different pictures: F-theory, the D7 worldvolume theory and D9-anti-D9 tachyon condensation. A significant complication is that consistent D7-branes in the presence of O7^- planes are generically singular, with singularities locally modeled by the Whitney Umbrella. This invalidates the standard formulae for charges, moduli space and flux lattice dimensions. We infer the correct formulae by comparison to F-theory and derive them independently and more generally from the tachyon picture, and relate these numbers to the closed string massless spectrum of the orientifold compactification in an interesting way. We furthermore give concrete recipes to explicitly and systematically construct nontrivial D-brane worldvolume flux vacua in arbitrary Calabi-Yau orientifolds, illustrate how to read off D-brane flux content, enhanced gauge groups and c...
Apostolopoulos, P S; Saridakis, E N; Tetradis, N; Apostolopoulos, Pantelis S.; Brouzakis, Nikolaos; Saridakis, Emmanuel N.; Tetradis, Nikolaos
2005-01-01
We discuss features of the brane cosmological evolution that arise through the presence of matter in the bulk. As these deviations from the conventional evolution are not associated with some observable matter component on the brane, we characterize them as mirage effects. We review an example of expansion that can be attributed to mirage non-relativistic matter (mirage cold dark matter) on the brane. The real source of the evolution is an anisotropic bulk fluid with negative pressure along the extra dimension. We also study the general problem of exchange of real non-relativistic matter between the brane and the bulk, and discuss the related mirage effects. Finally, we derive the brane cosmological evolution within a bulk that contains a global monopole (hedgehog) configuration. This background induces a mirage curvature term in the effective Friedmann equation, which can cause a brane Universe with positive spatial curvature to expand forever.
Light-cone M5 and multiple M2-branes
Bandos, Igor A
2008-01-01
We present the light-cone gauge fixed Lagrangian for the M5-brane; it has a residual `exotic' gauge invariance with the group of 5-volume preserving diffeomorphisms, SDiff(5), as gauge group. For an M5-brane of topology R2 x M3, for closed 3-manifold M3, we find an infinite tension limit that yields an SO(8)-invariant (1+2)-dimensional field theory with `exotic' SDiff(3) gauge invariance. We show that this field theory is the Carrollian limit of the Nambu bracket realization of the `BLG' model for multiple M2-branes.
Screening bulk curvature in the presence of large brane tension
Agarwal, Nishant; Khoury, Justin; Trodden, Mark
2011-01-01
We study a flat brane solution in an effective 5D action for cascading gravity and propose a mechanism to screen extrinsic curvature in the presence of a large tension on the brane. The screening mechanism leaves the bulk Riemann-flat, thus making it simpler to generalize large extra dimension dark energy models to higher codimensions. By studying an action with cubic interactions for the brane-bending scalar mode, we find that the perturbed action suffers from ghostlike instabilities for positive tension, whereas it can be made ghost-free for sufficiently small negative tension.
Gravity Localization and Effective Newtonian Potential for Bent Thick Branes
Guo, Heng; Liu, Yu-xiao; Wei, Shao-Wen; Fu, Chun-E
2010-01-01
In this letter, we first investigate the gravity localization and mass spectrum of gravity KK modes on de Sitter and Anti-de Sitter thick branes. Then, the effective Newtonian gravitational potentials for these bent branes are discussed by the two typical examples. The corrections of the Newtonian potential turns out to be $\\Delta U(r)\\sim 1/r^{2}$ at small $r$ for both cases. These corrections are very different from that of the Randall-Sundrum brane model $\\Delta U(r)\\sim 1/r^{3}$.
d-Brane Instantons in Type II Orientifolds
Blumenhagen, Ralph; Cvetič, Mirjam; Kachru, Shamit; Weigand, Timo
2009-11-01
We review recent progress in determining the effects of d-brane instantons in [Formula: see text] supersymmetric compactifications of Type II string theory to four dimensions. We describe the abstract d-brane instanton calculus for holomorphic couplings such as the superpotential, the gauge kinetic function, and higher fermionic F-terms, and we briefly discuss the implications of background fluxes for the instanton sector. We then summarize the concrete consequences of stringy d-brane instantons for the construction of semirealistic models of particle physics or supersymmetry breaking in compact and noncompact geometries.
A Compact Codimension Two Braneworld with Precisely One Brane
Akerblom, Nikolas
2010-01-01
Building on earlier work on football shaped extra dimensions, we construct a compact codimension two braneworld with precisely one brane. The two extra dimensions topologically represent a 2-torus which is stabilized by a bulk cosmological constant and magnetic flux. The torus has positive constant curvature almost everywhere, except for a single conical singularity at the location of the brane. In contradistinction to the football shaped case, there is no fine-tuning required for the brane tension. We also present some plausibility arguments why the model should not suffer from serious stability issues.
Lombardo, Davide M; Risoli, Stefano
2016-01-01
We consider the ${\\cal N}=1$ superpotential generated in type-II orientifold models by non-geometric fluxes. In particular, we focus on the family of $P$ fluxes, that are related by T-duality transformations to the S-dual of the $Q$ flux. We determine the general rule that transforms a given flux in this family under a single T-duality transformation. This rule allows to derive a complete expression for the superpotential for both the IIA and the IIB theory for the particular case of a $T^6/[\\mathbb{Z}_2 \\times \\mathbb{Z}_2 ]$ orientifold. We then consider how these fluxes modify the generalised Bianchi identities. In particular, we derive a fully consistent set of quadratic constraints coming from the NS-NS Bianchi identities. On the other hand, the $P$ flux Bianchi identities induce tadpoles, and we determine a set of exotic branes that can be consistently included in order to cancel them. This is achieved by determining a universal transformation rule under T-duality satisfied by all the branes in string t...
Brane gravity, higher derivative terms and non-locality
Mukohyama, S
2002-01-01
In brane world scenarios with a bulk scalar field between two branes it is known that 4-dimensional Einstein gravity is restored at low energies on either brane. By using a gauge-invariant gravitational and scalar perturbation formalism we extend the theory of weak gravity in the brane world scenarios to higher energies, or shorter distances. We argue that for general potentials of the scalar field and a general conformal transformation to a frame in which matter on the branes is minimally coupled to the metric, weak gravity on either brane is compatible with 4-dimensional higher derivative gravity. In particular, Newton's constant and the coefficients of curvature-squared terms in the 4-dimensional effective action are determined up to an ambiguity of adding a Gauss-Bonnet topological term. In other words, we provide the brane-world realization of the so called $R^2$ model without utilizing a quantum theory. We discuss the appearance of composite spin-2 and spin-0 fields in addition to the graviton on the br...
Sepehri, Alireza
2016-07-01
Recently, some authors (Cruz and Rojas, 2013 [1]) have constructed a Born-Infeld type action which may be written in terms of the Lovelock brane Lagrangians for a given dimension p. We reconsider their model in M-theory and study the process of birth and growth of nonlinear spinor and bosonic gravity during the construction of Mp-branes. Then, by application of this idea to BIonic system, we construct a BIonic superconductor in the background of nonlinear gravity. In this model, first, M0-branes link to each other and build an M5-brane and an anti-M5-brane connected by an M2-brane. M0-branes are zero dimensional objects that only scalars are attached to them. By constructing higher dimensional branes from M0-branes, gauge fields are produced. Also, if M0-branes don't link to each other completely, the symmetry of system is broken and fermions are created. The curvature produced by fermions has the opposite sign the curvature produced by gauge fields. Fermions on M5-branes and M2 plays the role of bridge between them. By passing time, M2 dissolves in M5's and nonlinear bosonic and spinor gravities are produced. By closing M5-branes towards each other, coupling of two identical fermions on two branes to each other causes that the square mass of their system becomes negative and some tachyonic states are created. For removing these tachyons, M5-branes compact, the sign of gravity between branes reverses, anti-gravity is produced which causes that branes and identical fermions get away from each other. This is the reason for the emergence of Pauli exclusion principle in Bionic system. Also, the spinor gravity vanishes and its energy builds a new M2 between M5-branes. We obtain the resistivity in this system and find that its value decreases by closing M5 branes to each other and shrinks to zero at colliding point of branes. This idea has different applications. For example, in cosmology, universes are located on M5-branes and M2-brane has the role of bridge between
Information-entropic measure in the Weyl pure geometrical thick brane
Correa, R A C; Almeida, C A S; Moraes, P H R S
2016-01-01
This letter aims to analyse the so-called configurational entropy in the Weyl pure geometrical thick brane model. The Weyl structure plays a prominent role in the thickness of this model. We find a set of parameters associated to the brane width where the configurational entropy exhibits critical points. Furthermore, we show, by means of this information-theoretical measure, that a stricter bound on the parameter of Weyl pure geometrical brane model arises from the CE.
International Nuclear Information System (INIS)
We suggest a duality-invariant formula for the entropy and temperature of nonextreme black holes in supersymmetric string theory. The entropy is given in terms of the duality-invariant parameter of the deviation from extremality and 56 SU(8) covariant central charges. It interpolates between the entropies of Schwarzschild solution and extremal solutions with various amount of unbroken supersymmetries, and therefore, serves for classification of black holes in supersymmetric string theories. We introduce the second auxiliary 56 via an E(7) symmetric constraint. The symmetric and antisymmetric combinations of these two multiplets are related via moduli to the corresponding two fundamental representations of E(7): brane and antibrane open-quote open-quote numbers.close-quote close-quote Using the CPT as well as C symmetry of the entropy formula and duality one can explain the mysterious simplicity of the nonextreme black hole area formula in terms of branes and antibranes. copyright 1996 The American Physical Society
Borsten, L; Dahanayake, D; Duff, M J; Ebrahim, H; Rubens, W
2008-06-27
Recent work has established a correspondence between the tripartite entanglement measure of three qubits and the macroscopic entropy of the four-dimensional 8-charge STU black hole of supergravity. Here we consider the configurations of intersecting D3-branes, whose wrapping around the six compact dimensions T6 provides the microscopic string-theoretic interpretation of the charges, and associate the three-qubit basis vectors |ABC>, (A, B, C=0 or 1) with the corresponding 8 wrapping cycles. In particular, we relate a well-known fact of quantum information theory, that the most general real three-qubit state can be parameterized by four real numbers and an angle, to a well-known fact of string theory, that the most general STU black hole can be described by four D3-branes intersecting at an angle. PMID:18643650
Curved branes with regular support
Antoniadis, Ignatios; Klaoudatou, Ifigeneia
2016-01-01
We study spacetime singularities in a general five-dimensional braneworld with curved branes satisfying four-dimensional maximal symmetry. The bulk is supported by an analog of perfect fluid with the time replaced by the extra coordinate. We show that contrary to the existence of finite distance singularities from the brane location in any solution with flat (Minkowski) branes, in the case of curved branes there are singularity-free solutions for a range of equations of state compatible with the null energy condition.
Figueroa-O'Farrill, J M
1999-01-01
Certain supergravity solutions (including domain walls and the magnetic fivebrane) have recently been generalised by Brecher and Perry by relaxing the condition that the brane worldvolume be flat. In this way they obtain examples in which the brane worldvolume is a static spacetime admitting parallel spinors. In this note we simply point out that the restriction to static spacetimes is unnecessary, and in this way exhibit solutions where the brane worldvolume is an indecomposable Ricci-flat lorentzian manifold admitting parallel spinors. We discuss more Ricci-flat fivebranes and domain walls, as well as new Ricci-flat D3-branes.
Wronskians, dualities and FZZT-Cardy branes
Chan, Chuan-Tsung; Irie, Hirotaka; Niedner, Benjamin; Yeh, Chi-Hsien
2016-09-01
The resolvent operator plays a central role in matrix models. For instance, with utilizing the loop equation, all of the perturbative amplitudes including correlators, the free-energy and those of instanton corrections can be obtained from the spectral curve of the resolvent operator. However, at the level of non-perturbative completion, the resolvent operator is generally not sufficient to recover all the information from the loop equations. Therefore it is necessary to find a sufficient set of operators which provide the missing non-perturbative information. In this paper, we study generalized Wronskians of the Baker-Akhiezer systems as a manifestation of these new degrees of freedom. In particular, we derive their isomonodromy systems and then extend several spectral dualities to these systems. In addition, we discuss how these Wronskian operators are naturally aligned on the Kac table. Since they are consistent with the Seiberg-Shih relation, we propose that these new degrees of freedom can be identified as FZZT-Cardy branes in Liouville theory. This means that FZZT-Cardy branes are the bound states of elemental FZZT branes (i.e. the twisted fermions) rather than the bound states of principal FZZT-brane (i.e. the resolvent operator).
Gibbons, G. W.
1998-01-01
A BIon may be defined as a finite energy solution of a non-linear field theory with distributional sources. By contrast a soliton is usually defined to have no sources. I show how harmonic coordinates map the exteriors of the topologically and causally non-trivial spacetimes of extreme p-branes to BIonic solutions of the Einstein equations in a topologically trivial spacetime in which the combined gravitational and matter energy momentum is located on distributional sources. As a consequence ...
Black Branes as Piezoelectrics
Armas, Jay; Obers, Niels A
2012-01-01
We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.
Linch, William D
2016-01-01
We generalize the current algebra of constraints of U-duality-covariant critical superstrings to include the generator responsible for the dynamics of the fundamental brane. This allows us to define $\\kappa$ symmetry and to write a worldvolume action in Hamiltonian form that is manifestly supersymmetric in the target space. The Lagrangian form of this action is generally covariant, but the worldvolume metric has fewer components than expected.
Black branes as piezoelectrics.
Armas, Jay; Gath, Jakob; Obers, Niels A
2012-12-14
We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six. PMID:23368298
Black strings from minimal geometric deformation in a variable tension brane-world
International Nuclear Information System (INIS)
We study brane-world models with variable brane tension and compute corrections to the horizon of a black string along the extra dimension. The four-dimensional geometry of the black string on the brane is obtained by means of the minimal geometric deformation approach, and the bulk corrections are then encoded in additional terms involving the covariant derivatives of the variable brane tension. Our investigation shows that the variable brane tension strongly affects the shape and evolution of the black string horizon along the extra dimension, at least in a near-brane expansion. In particular, we apply our general analysis to a model motivated by the Eötvös branes, where the variable brane tension is related to the Friedmann–Robertson–Walker brane-world cosmology. We show that for some stages in the evolution of the universe, the black string warped horizon collapses to a point and the black string has correspondingly finite extent along the extra dimension. Furthermore, we show that in the minimal geometric deformation of a black hole on the variable tension brane, the black string has a throat along the extra dimension, whose area tends to zero as time goes to infinity. (paper)
Black strings from minimal geometric deformation in a variable tension brane-world
Casadio, R.; Ovalle, J.; da Rocha, Roldão
2014-02-01
We study brane-world models with variable brane tension and compute corrections to the horizon of a black string along the extra dimension. The four-dimensional geometry of the black string on the brane is obtained by means of the minimal geometric deformation approach, and the bulk corrections are then encoded in additional terms involving the covariant derivatives of the variable brane tension. Our investigation shows that the variable brane tension strongly affects the shape and evolution of the black string horizon along the extra dimension, at least in a near-brane expansion. In particular, we apply our general analysis to a model motivated by the Eötvös branes, where the variable brane tension is related to the Friedmann-Robertson-Walker brane-world cosmology. We show that for some stages in the evolution of the universe, the black string warped horizon collapses to a point and the black string has correspondingly finite extent along the extra dimension. Furthermore, we show that in the minimal geometric deformation of a black hole on the variable tension brane, the black string has a throat along the extra dimension, whose area tends to zero as time goes to infinity.
A delicate universe: compactification obstacles to D-brane inflation.
Baumann, Daniel; Dymarsky, Anatoly; Klebanov, Igor R; McAllister, Liam; Steinhardt, Paul J
2007-10-01
We investigate whether explicit models of warped D-brane inflation are possible in string compactifications. To this end, we study the potential for D3-brane motion in a warped conifold that includes holomorphically embedded D7-branes involved in moduli stabilization. The presence of the D7-branes significantly modifies the inflaton potential. We construct an example based on a very simple and symmetric embedding due to Kuperstein, z1= const, in which it is possible to fine-tune the potential so that slow-roll inflation can occur. The resulting model is rather delicate: inflation occurs in the vicinity of an inflection point, and the cosmological predictions are extremely sensitive to the precise shape of the potential.
Probing bound states of D-branes
Lifschytz, G
1996-01-01
A zero-brane is used to probe non-threshold BPS bound states of ($p$, $p+2$,$p+4$)-branes. At long distances the stringy calculation agrees with the supergravity calculations. The supergravity description is given, using the interpretation of the $D=8$ dyonic membrane as the bound state of a two-brane inside a four-brane. We investigate the short distance structure of these bound states, compute the phase shift of the scattered zero-brane and find the bound states characteristic size. It is found that there should be a supersymmetric solution of type IIa supergravity, describing a bound state of a zero-brane and two orthogonal two-brane, all inside a four-brane , with an additional unbound zero-brane. We comment on the relationship between $p$-branes and $(p-2)$-branes.
A Brane World Perspective on the Cosmological Constant and the Hierarchy Problems
Flanagan, Eanna; Jones, Nicholas; Stoica, Horace; Tye, S.-H. Henry; Wasserman, Ira
2000-01-01
We elaborate on the recently proposed static brane world scenario, where the effective 4-D cosmological constant is exponentially small when parallel 3-branes are far apart. We extend this result to a compactified model with two positive tension branes. Besides an exponentially small effective 4-D cosmological constant, this model incorporates a Randall-Sundrum-like solution to the hierarchy problem. Furthermore, the exponential factors for the hierarchy problem and the cosmological constant ...
Brane-antibrane systems and the thermal life of neutral black holes
Saremi, O; Saremi, Omid; Peet, Amanda W.
2004-01-01
A brane-antibrane model for the entropy of neutral black branes is developed, following on from the work of Danielsson, Guijosa and Kruczenski [1]. The model involves equal numbers of Dp-branes and anti-Dp-branes, and arbitrary angular momenta, and covers the cases p=0,1,2,3,4. The thermodynamic entropy is reproduced by the strongly coupled field theory, up to a power of two. The strong-coupling physics of the p=0 case is further developed numerically, using techniques of Kabat, Lifschytz et al. [2,3], in the context of a toy model containing the tachyon and the bosonic degrees of freedom of the D0-brane and anti-D0-brane quantum mechanics. Preliminary numerical results show that strong-coupling finite-temperature stabilization of the tachyon is possible, in this context.
Non-singular twisted s-branes from rotating branes
International Nuclear Information System (INIS)
We show that rotating p-brane solutions admit an analytical continuation to become twisted Sp-branes. Although a rotating p-brane has a naked singularity for large angular momenta, the corresponding S-brane configuration is regular everywhere and exhibits a smooth bounce between two phases of Minkowski spacetime. If the foliating hyperbolic space of the transverse space is of even dimension, such as for the twisted SM5-brane, then for an appropriate choice of parameters the solution smoothly flows from a warped product of two-dimensional de Sitter spacetime, five-dimensional Euclidean space and a hyperbolic 4-space in the infinite past to Minkowski spacetime in the infinite future. We also show that non-singular S-Kerr solutions can arise from higher-dimensional Kerr black holes, so long as all (all but one) angular momenta are non-vanishing for even (odd) dimensions. (author)
Random Matrices, Boundaries and Branes
Niedner, Benjamin
2016-01-01
This thesis is devoted to the application of random matrix theory to the study of random surfaces, both discrete and continuous; special emphasis is placed on surface boundaries and the associated boundary conditions in this formalism. In particular, using a multi-matrix integral with permutation symmetry, we are able to calculate the partition function of the Potts model on a random planar lattice with various boundary conditions imposed. We proceed to investigate the correspondence between the critical points in the phase diagram of this model and two-dimensional Liouville theory coupled to conformal field theories with global $\\mathcal{W}$-symmetry. In this context, each boundary condition can be interpreted as the description of a brane in a family of bosonic string backgrounds. This investigation suggests that a spectrum of initially distinct boundary conditions of a given system may become degenerate when the latter is placed on a random surface of bounded genus, effectively leaving a smaller set of ind...
Emergence and oscillation of cosmic space by joining M1-branes
Energy Technology Data Exchange (ETDEWEB)
Sepehri, Alireza [Shahid Bahonar University, Faculty of Physics, Kerman (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Rahaman, Farook [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Capozziello, Salvatore [Universita di Napoli Federico II, Dipartimento di Fisica ' ' E. Pancini' ' , Naples (Italy); Gran Sasso Science Institute (INFN), L' Aquila (Italy); Tomsk State Pedagogical University, Tomsk (Russian Federation); INFN Sezione di Napoli, Naples (Italy); Ali, Ahmed Farag [Benha University, Department of Physics, Faculty of Science, Benha (Egypt); Pradhan, Anirudh [G L A University, Department of Mathematics, Institute of Applied Sciences and Humanities, Mathura, Uttar Pradesh (India)
2016-05-15
Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises; how could this model explain the oscillation of the universe between contraction and expansion branches? We try to address this issue in the framework of a BIonic system. In this model, M0-branes join to each other and give rise to a pair of M1-anti-M1-branes. The fields which live on these branes play the roles of massive gravitons that cause the emergence of a wormhole between them and formation of a BIon system. This wormhole dissolves into M1-branes and causes a divergence between the number of degrees of freedom on the boundary surface of M1 and the bulk leading to an expansion of M1-branes. When M1-branes become close to each other, the square energy of their system becomes negative and some tachyonic states emerge. To remove these states, M1-branes become compact, the sign of compacted gravity changes, causing anti-gravity to arise: in this case, branes get away from each other. By articulating M1-BIons, an M3-brane and an anti-M3-brane are created and connected by three wormholes forming an M3-BIon. This new system behaves like the initial system and by closing branes to each other, they become compact and, by getting away from each other, they open. Our universe is located on one of these M3-branes and, by compactifying the M3-brane, it contracts and, by opening it, it expands. (orig.)
Hadamard function and the vacuum currents in braneworlds with compact dimensions: Two-brane geometry
Bellucci, S.; Saharian, A. A.; Vardanyan, V.
2016-04-01
We evaluate the Hadamard function and the vacuum expectation value of the current density for a charged scalar field in the region between two codimension-one branes on the background of locally anti-de Sitter (AdS) spacetime with an arbitrary number of toroidally compactified spatial dimensions. Along compact dimensions periodicity conditions are considered with general values of the phases and on the branes Robin boundary conditions are imposed for the field operator. In addition, we assume the presence of a constant gauge field. The latter gives rise to an Aharonov-Bohm-type effect on the vacuum currents. There exists a range in the space of the Robin coefficients for separate branes where the vacuum state becomes unstable. Compared to the case of the standard AdS bulk, in models with compact dimensions the stability condition imposed on the parameters is less restrictive. The current density has nonzero components along compact dimensions only. These components are decomposed into the brane-free and brane-induced contributions. Different representations are provided for the latter that are well suited for the investigation of the near-brane, near-AdS boundary and near-AdS horizon asymptotics. An important feature, that distinguishes the current density from the expectation values of the field squared and energy-momentum tensor, is its finiteness on the branes. In particular, for Dirichlet boundary conditions the current density vanishes on the branes. We show that, depending on the constants in the boundary conditions, the presence of the branes may either increase or decrease the current density compared with that for the brane-free geometry. Applications are given to the Randall-Sundrum 2-brane model with extra compact dimensions. In particular, we estimate the effects of the hidden brane on the current density on the visible brane.
Emergence and oscillation of cosmic space by joining M1-branes
Sepehri, Alireza; Rahaman, Farook; Capozziello, Salvatore; Ali, Ahmed Farag; Pradhan, Anirudh
2016-05-01
Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises; how could this model explain the oscillation of the universe between contraction and expansion branches? We try to address this issue in the framework of a BIonic system. In this model, M0-branes join to each other and give rise to a pair of M1-anti- M1-branes. The fields which live on these branes play the roles of massive gravitons that cause the emergence of a wormhole between them and formation of a BIon system. This wormhole dissolves into M1-branes and causes a divergence between the number of degrees of freedom on the boundary surface of M1 and the bulk leading to an expansion of M1-branes. When M1-branes become close to each other, the square energy of their system becomes negative and some tachyonic states emerge. To remove these states, M1-branes become compact, the sign of compacted gravity changes, causing anti-gravity to arise: in this case, branes get away from each other. By articulating M1-BIons, an M3-brane and an anti- M3-brane are created and connected by three wormholes forming an M3-BIon. This new system behaves like the initial system and by closing branes to each other, they become compact and, by getting away from each other, they open. Our universe is located on one of these M3-branes and, by compactifying the M3-brane, it contracts and, by opening it, it expands.
Brane world cosmology with Gauss-Bonnet and induced gravity terms
Brown, R A
2006-01-01
In this thesis we investigate certain cosmological brane world models of the Randall-Sundrum type. The models are motivated by string theory but we focus on the phenomenology of the cosmology. Two models of specific interest are the Dvali-Gabadadze-Porrati (DGP, induced-gravity) model, where the brane action is modified, and the Gauss-Bonnet model where the bulk action is modified. Both of these modifications maybe motivated by string theory. We provide a brief review of Randall-Sundrum models and then consider the Kaluza-Klein modes on Minkowski and de Sitter branes, in both the two and one brane cases. The spectrum obtained for the de Sitter branes is a new result. We then consider a Friedmann-Robertson-Walker brane in order to investigate the cosmological dynamics on the brane. We present a brief discussion of the DGP and Gauss-Bonnet brane worlds. We then investigate the Gauss-Bonnet-Induced-Gravity (GBIG) model where the Gauss-Bonnet (GB) bulk term is combined with the induced-gravity (IG) brane term of ...
Composite p-branes on Product of Einstein Spaces
Ivashchuk, V D
1998-01-01
A multidimensional gravitational model with several scalar fields, fields of forms and cosmological constant is considered. When scalar fields are constant and composite p-brane monopole-like ansatz for the fields of forms is adopted, a wide class of solutions on product of n+1 Einstein spaces is obtained. These solutions are the composite p-brane generalizations of the Freund-Rubin solution. Some examples including the AdS_m x S^k x... solutions are considered.
f(R)-Einstein-Palatini Formalism and smooth branes
da Silva, Paulo Michel L T
2016-01-01
In this work, we present the f(R)-Einstein-Palatini formalism in arbitrary dimensions and the study of consistency applied to brane models, the so-called braneworld sum rules. We show that it is possible a scenario of thick branes in five dimensions with compact extra dimension in the framework of the f(R)-Einstein-Palatini theory by the accomplishment of an assertive criteria.
Indian Academy of Sciences (India)
M S Modgil; S Panda; S Sengupta
2004-03-01
A Kerr metric describing a rotating black hole is obtained on the three brane in a five-dimensional Randall-Sundrum brane world by considering a rotating five-dimensional black string in the bulk. We examine the causal structure of this space-time through the geodesic equations.
Brane Inflation and Defect Formation
Davis, A. C.; Brax, P.H.; van de Bruck, C.
2008-01-01
Brane inflation and the production of topological defects at the end of the inflationary phase are discussed. After a description of the inflationary setup we discuss the properties of the cosmic strings produced at the end of inflation. Specific examples of brane inflation are described: $D-\\bar D$ inflation, $D3/D7$ inflation and modular inflation
Covariant approach of perturbations in Lovelock type brane gravity
Norma, Bagatella-Flores; Miguel, Cruz; Efrain, Rojas
2016-01-01
We develop a covariant scheme to describe the dynamics of small perturbations on Lovelock type branes probing a Minkowski spacetime. The higher-dimensional analogue of the Jacobi equation in this theory becomes a wave type equation for a scalar field $\\Phi$. Whithin this framework, we analyse the stability of spherically symmetric branes with a de Sitter geometry floating in a flat Minkowski spacetime where we find that the Jacobi equation specializes to a Klein-Gordon equation for a scalar field possessing a tachyonic mass. This fact shows that, to some extent, these type of branes share the symmetries of the usual Dirac-Nambu-Goto (DNG) action which is by no means coincidental because the DNG model is the simplest included in the Lovelock type brane gravity.
The Cosmological Constant Problem from a Brane-World Perspective
Förste, S; Lavignac, Stephane; Nilles, Hans Peter; Forste, Stefan; Lalak, Zygmunt; Lavignac, St\\'ephane; Nilles, Hans Peter
2000-01-01
We point out several subtleties arising in brane-world scenarios of cosmological constant cancellation. We show that solutions with curvature singularities are inconsistent, unless the contribution to the effective four-dimentional cosmological constant of the physics that resolves the singularities is fine-tuned. This holds for both flat and curved branes. Irrespective of this problem, we then study an isolated class of flat solutions in models where a bulk scalar field with a vanishing potential couples to a 3-brane. We give an example where the introduction of a bulk scalar potential results in a nonzero cosmological constant. Finally we comment on the stability of classical solutions of the brane system with respect to quantum corrections.
Mirror Symmetry for Toric Branes on Compact Hypersurfaces
Alim, M; Mayr, P; Mertens, A
2009-01-01
We use toric geometry to study open string mirror symmetry on compact Calabi-Yau manifolds. For a mirror pair of toric branes on a mirror pair of toric hypersurfaces we derive a canonical hypergeometric system of differential equations, whose solutions determine the open/closed string mirror maps and the partition functions for spheres and discs. We define a linear sigma model for the brane geometry and describe a correspondence between dual toric polyhedra and toric brane geometries. The method is applied to study examples with obstructed and classically unobstructed brane moduli at various points in the deformation space. Computing the instanton expansion at large volume in the flat coordinates on the open/closed deformation space we obtain predictions for enumerative invariants.
Towards the stabilization of extra dimensions by brane dynamics
Kitazawa, Noriaki
2014-01-01
All models of elementary particles and their interactions derived from String Theory involve a compact six-dimensional internal space. Its volume and shape should be fixed or stabilized, since otherwise massless scalar fields (moduli) reflecting their deformations appear in our four-dimensional space-time, with sizable effects on known particles and fields. A mechanism is proposed to stabilize the compact space without fluxes of three-form fields from closed strings. Our main motivation and goal is to proceed insofar as possible within conventional string world-sheet theory. As we shall see, D-branes with magnetic flux ("magnetized D-branes") and the forces between them can be used to this end. We investigate here some necessary ingredients: open string one-loop vacuum amplitudes between magnetized D-branes, magnetized D-branes at orbifold singularities, and potential energies among all of them in the compact space that result from tree-level closed string exchanges.
Torus-like Dielectric D2-brane
Hyakutake, Yoshifumi
2001-01-01
We find new solutions corresponding to torus-like generalization of dielectric D2-brane from the viewpoint of D2-brane action and N D0-branes one. These are meta-stable and would decay to the spherical dielectric D2-brane.
Two-brane system in a vacuum bulk with a single equation of state
Perez, Juan L; Urena-Lopez, L Arturo; 10.1063/1.4748545
2012-01-01
We study the cosmology of a two-brane model in a five-dimensional spacetime, where the extra spatial coordinate is compactifed on an orbifold. Additionally, we consider the existence on each brane of matter fields that evolve in time. Solving the Einstein equations in a vacuum bulk, we can show how the matter fields in both branes are connected and they do not evolve independently
Directory of Open Access Journals (Sweden)
Neil Lambert
2015-10-01
Full Text Available We construct the action for N M2-branes on S1/Z2. The resulting theory has a gauge anomaly but this can be cancelled if the two fixed point planes each support 8 chiral Fermions in the fundamental of U(N. Taking the low energy limit leads to the worldsheet theory of N free heterotic strings whose quantization induces an E8 spacetime gauge symmetry on each fixed point plane. Thus this paper presents a non-abelian worldvolume analogue of the classic Hořava–Witten analysis.
Remarks on brane and antibrane dynamics
Michel, Ben; Polchinski, Joseph; Puhm, Andrea; Saad, Philip
2014-01-01
We develop the point of view that brane actions should be understood in the context of effective field theory, and that this is the correct way to treat classical as well as loop divergences. We illustrate this idea in a simple model. We then consider the implications for the dynamics of antibranes in flux backgrounds, focusing on the simplest case of a single antibrane. We argue that there is no tachyonic instability at zero temperature, but there is a nonperturbative process in which an antibrane annihilates with its screening cloud. This is distinct from the NS5-brane instanton decay. Constraints on models of metastable supersymmetry breaking by antibranes may be tightened, but there is no problem of principle with this mechanism.
Transport properties of spacetime-filling branes
Energy Technology Data Exchange (ETDEWEB)
Tarrío, Javier [Departament de Física Fonamental and Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, ES-08028, Barcelona (Spain)
2014-04-07
A model consisting of (d+1)-dimensional gravity coupled to spacetime filling charged branes is used to study the effects of backreaction. The charged black holes arising from this simple model reflect the non-linearity of the gauge field and are thermodynamically stable. By analysing fluctuations of the system we corroborate that at low values of the temperature (or large chemical potential) backreaction effects from the branes are dominant. We also provide a generalisation of the Iqbal and Liu strategy to calculate the DC conductivity, in which a mass term for the gauge field fluctuation is included. This mass term gives the value of the residue of the pole at zero frequency in the imaginary part of the AC conductivity, as well as the running of the DC conductivity with the bulk radius.
Transport properties of spacetime-filling branes
Tarrio, Javier
2013-01-01
A model consisting of (d+1)-dimensional gravity coupled to spacetime filling charged branes is used to study the effects of backreaction. The charged black holes arising from this simple model reflect the non-linearity of the gauge field and are thermodynamically stable. By analysing fluctuations of the system we corroborate that at low values of the temperature (or large chemical potential) backreaction effects from the branes are dominant. We also provide a generalisation of the Iqbal and Liu strategy to calculate the DC conductivity, in which a mass term for the gauge field fluctuation is included. This mass term gives the value of the residue of the pole at zero frequency in the imaginary part of the AC conductivity, as well as the running of the DC conductivity with the bulk radius.
Transport properties of spacetime-filling branes
International Nuclear Information System (INIS)
A model consisting of (d+1)-dimensional gravity coupled to spacetime filling charged branes is used to study the effects of backreaction. The charged black holes arising from this simple model reflect the non-linearity of the gauge field and are thermodynamically stable. By analysing fluctuations of the system we corroborate that at low values of the temperature (or large chemical potential) backreaction effects from the branes are dominant. We also provide a generalisation of the Iqbal and Liu strategy to calculate the DC conductivity, in which a mass term for the gauge field fluctuation is included. This mass term gives the value of the residue of the pole at zero frequency in the imaginary part of the AC conductivity, as well as the running of the DC conductivity with the bulk radius
Cecotti, Sergio; Heckman, Jonathan J; Vafa, Cumrun
2010-01-01
We introduce T-branes, or "triangular branes," which are novel non-abelian bound states of branes characterized by the condition that on some loci, their matrix of normal deformations, or Higgs field, is upper triangular. These configurations refine the notion of monodromic branes which have recently played a key role in F-theory phenomenology. We show how localized matter living on complex codimension one subspaces emerge, and explain how to compute their Yukawa couplings, which are localized in complex codimension two. Not only do T-branes clarify what is meant by brane monodromy, they also open up a vast array of new possibilities both for phenomenological constructions and for purely theoretical applications. We show that for a general T-brane, the eigenvalues of the Higgs field can fail to capture the spectrum of localized modes. In particular, this provides a method for evading some constraints on F-theory GUTs which have assumed that the spectral equation for the Higgs field completely determines a loc...
Electroelasticity of Charged Black Branes
Armas, Jay; Obers, Niels A
2013-01-01
We present the first order corrected dynamics of fluid branes carrying higher-form charge by obtaining the general form of their equations of motion to pole-dipole order. Assuming linear response theory, we characterize the corresponding effective theory of stationary bent charged (an)isotropic fluid branes in terms of two sets of response coefficients, the Young modulus and the piezoelectric moduli. We subsequently find large classes of examples in gravity of this effective theory, by constructing stationary strained charged black brane solutions to first order in a derivative expansion. Using solution generating techniques and bent neutral black branes as a seed solution, we obtain a class of charged black brane geometries carrying smeared Maxwell charge in Einstein-Maxwell-dilaton gravity. In the specific case of ten-dimensional space-time we furthermore use T-duality to generate bent black branes with higher-form charge, including smeared D-branes of type II string theory. By subsequently measuring the be...
Gravitational backreaction of anti-D branes in the warped compactification
Koyama, Kayoko; Koyama, Kazuya
2005-01-01
We derive a low-energy effective theory for gravity with anti-D branes, which are essential to get de Sitter solutions in the type IIB string warped compactification, by taking account of gravitational backreactions of anti-D branes. In order to see the effects of the self-gravity of anti-D branes, a simplified model is studied where a 5-dimensional anti-de Sitter ({\\it AdS}) spacetime is realized by the bulk cosmological constant and the 5-form flux, and anti-D branes are coupled to the 5-fo...
Black Strings from Minimal Geometric Deformation in a Variable Tension Brane-World
Casadio, Roberto; da Rocha, Roldao
2013-01-01
We study brane-world models with variable brane tension and compute corrections to the horizon of a black string along the extra dimension. The four-dimensional geometry of the black string on the brane is obtained by means of the minimal geometric deformation approach, and the bulk corrections are then encoded in additional terms involving the covariant derivatives of the variable brane tension. Our investigation shows that the variable brane tension strongly affects the shape and evolution of the black string horizon along the extra dimension, at least in a near-brane expansion. In particular, we apply our general analysis to a model motivated by the E\\"otv\\"os branes, where the variable brane tension is related to the Friedmann-Robertson-Walker brane-world cosmology. We show that for some stages in the evolution of the universe, the black string warped horizon collapses to a point and the black string has correspondingly finite extent along the extra dimension. Furthermore, we show that in the minimal geom...
Hybrid metric-Palatini brane system
Fu, Qi-Ming; Liu, Yu-Xiao
2016-01-01
It is known that the metric and Palatini formalisms of gravity theories have their own interesting features but also suffer from some different drawbacks. Recently, a novel gravity theory called hybrid metric-Palatini gravity was put forward to cure or improve their individual deficiencies. The action of this gravity theory is a hybrid combination of the usual Einstein-Hilbert action and a $f(\\mathcal{R})$ term constructed by the Palatini formalism. Interestingly, it seems that the existence of a light and long-range scalar field in this gravity may modify the cosmological and galactic dynamics without conflicting with the laboratory and Solar System tests. In this paper we focus on the tensor perturbation of thick branes in this novel gravity theory. We consider two models as examples, namely, the thick branes constructed by a background scalar field and by pure gravity. The thick branes in both models have no inner structure. However, the graviton zero mode in the first model has inner structure when the pa...
Clark, T E
2016-01-01
Coset methods are used to determine the action of a co-dimension one brane (domain wall) embedded in (d+1)-dimensional AdS space in the Carroll limit in which the speed of light goes to zero. The action is invariant under the non-linearly realized symmetries of the AdS-Carroll spacetime. The Nambu-Goldstone field exhibits a static spatial distribution for the brane with a time varying momentum density related to the brane's spatial shape as well as the AdS-C geometry. The AdS-C vector field dual theory is obtained.
Exotic branes and nongeometric backgrounds.
de Boer, Jan; Shigemori, Masaki
2010-06-25
When string or M theory is compactified to lower dimensions, the U-duality symmetry predicts so-called exotic branes whose higher-dimensional origin cannot be explained by the standard string or M-theory branes. We argue that exotic branes can be understood in higher dimensions as nongeometric backgrounds or U folds, and that they are important for the physics of systems which originally contain no exotic charges, since the supertube effect generically produces such exotic charges. We discuss the implications of exotic backgrounds for black hole microstate (non-)geometries. PMID:20867363
Localized Backreacted Flavor Branes in Holographic QCD
Burrington, Benjamin A; Sonnenschein, Jacob
2008-01-01
We investigate the perturbative (in $g_s N_{D8}$) backreaction of localized D8 branes in D4-D8 systems including in particular the Sakai Sugimoto model. We write down the explicit expressions of the backreacted metric, dilaton and RR form. We find that the backreaction remains small up to a radial value of $u \\ll \\ell_s/(g_s N_{D8})$, and that the background functions are smooth except at the D8 sources. In this perturbative window, the original embedding remains a solution to the equations of motion. Furthermore, the fluctuations around the original embedding, describing scalar mesons, do not become tachyonic due to the backreaction in the perturbative regime. This is is due to a cancelation between the DBI and CS parts of the D8 brane action in the perturbed background.
Slinky evolution of domain wall brane cosmology
Kadosh, Avihay; Pallante, Elisabetta
2012-01-01
Invoking an initial symmetry between the time $t$ and some extra spatial dimension $y$, we discuss a novel scenario where the dynamical formation of the 4-dim brane and its cosmological evolution are induced simultaneously by a common $ ty $ symmetry breaking mechanism. The local maximum of the underlying scalar potential is mapped onto a `watershed' curve in the $(t,y)$ plane; the direction tangent to this curve is identified as the cosmic time, whereas the perpendicular direction serves locally as the extra spatial dimension. Special attention is devoted to the so-called slinky configurations, whose brane cosmology is characterized by a decaying cosmological constant along the watershed curve. Such a slinky solution is first constructed within a simplified case where the watershed is constrained by $y=0$. The physical requirements (and the problematics) for a slinky configuration to generate a realistic model are then discussed in a more elaborated framework. Prospects for adding matter and radiation fields...
Radion stability and induced, on-brane geometries in an effective scalar-tensor theory of gravity
Kar, Sayan; SenGupta, Soumitra
2013-01-01
About a decade ago, using a specific expansion scheme, effective, on-brane scalar tensor theories of gravity were proposed by Kanno and Soda (Phys.Rev. {\\bf D 66} 083506 ,(2002)) in the context of the warped two brane model of Randall--Sundrum. The inter-related effective theories on both the branes were derived with the space-time dependent radion field playing a crucial role. Taking a re-look at this effective theory, we find cosmological and spherically symmetric, static solutions sourced by a radion--induced, effective stress energy, as well as additional, on-brane matter. The distance between the branes (governed by the time or space dependent radion) is shown to be stable and asymptotically non-zero, thereby setting aside any possibility of brane collisions. It turns out that the inclusion of on-brane matter plays a decisive role in stabilising the radion - a fact which we demonstrate through our solutions.
Sepehri, Alireza
2016-01-01
Recently, an interesting mechanism [Phys.Rev.Lett.106:231101,2011] has been proposed which produces all nonlinear terms in massive gravity to all orders . In this work, we reproduce these results in M-theory and consider the process of birth and growth of nonlinear gravity during the construction of Mp-branes. It has been shown that Mp brane are built up of p- M1-branes which each of them are connected to M1-branes of other Mp-brane through a wormhole. In this model, by increasing the number of dimensions, the number of nonlinear terms in relevant action of branes enhances and some theories like lovelock and nonlinear gravity are raised. By compacting M-branes, graviton fields in nonlinear gravity converts to photon fields and thus nonlinear electrodynamics are produced.
Emergence and expansion of cosmic space as due to M0-branes
International Nuclear Information System (INIS)
Recently, Padmanabhan (arXiv:1206.4916 [hepth]) discussed that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region causes the accelerated expansion of the universe. The main question arising is: what is the origin of this inequality between the surface degrees of freedom and the bulk degrees of freedom? We answer this question in M-theory. In our model, first M0-branes are compactified on one circle and N D0-branes are created. Then N D0-branes join each other, grow, and form one D5-branes. Next, the D5-brane is compactified on two circles and our universe's D3-brane, two D1-branes and some extra energies are produced. After that, one of the D1-branes, which is closer to the universe's brane, gives its energy into it, and this leads to an increase in the difference between the numbers of degrees of freedom and the occurring inflation era. With the disappearance of this D1-brane, the number of degrees of freedom of boundary surface and bulk region become equal and inflation ends. At this stage, extra energies that are produced due to the compactification cause an expansion of the universe and deceleration epoch. Finally, another D1-brane dissolves in our universe's brane, leads to an inequality between degrees of freedom, and there occurs a new phase of acceleration. (orig.)
Emergence and expansion of cosmic space as due to M0-branes
Energy Technology Data Exchange (ETDEWEB)
Sepehri, Alireza [Shahid Bahonar University, Faculty of Physics, Kerman (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Setare, Mohammad Reza [University of Kurdistan, Department of Science, Bijar (Iran, Islamic Republic of); Capozziello, Salvatore [Universita di Napoli Federico II, Dipartimento di Fisica, Naples (Italy); Complutense Univ. di Monte S. Angelo, Naples (Italy); Gran Sasso Science Institute (INFN), L' Aquila (Italy); INFN Sezione di Napoli, Naples (Italy)
2015-12-15
Recently, Padmanabhan (arXiv:1206.4916 [hepth]) discussed that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region causes the accelerated expansion of the universe. The main question arising is: what is the origin of this inequality between the surface degrees of freedom and the bulk degrees of freedom? We answer this question in M-theory. In our model, first M0-branes are compactified on one circle and N D0-branes are created. Then N D0-branes join each other, grow, and form one D5-branes. Next, the D5-brane is compactified on two circles and our universe's D3-brane, two D1-branes and some extra energies are produced. After that, one of the D1-branes, which is closer to the universe's brane, gives its energy into it, and this leads to an increase in the difference between the numbers of degrees of freedom and the occurring inflation era. With the disappearance of this D1-brane, the number of degrees of freedom of boundary surface and bulk region become equal and inflation ends. At this stage, extra energies that are produced due to the compactification cause an expansion of the universe and deceleration epoch. Finally, another D1-brane dissolves in our universe's brane, leads to an inequality between degrees of freedom, and there occurs a new phase of acceleration. (orig.)
Solitons on intersecting 3-branes
Cottrell, Willam; Pillai, Mohandas
2014-01-01
We consider a system consisting of a pair of D3 branes intersecting each other along a line such that half of the 16 supersymmetries are preserved. We then study the existence of magnetic monopole solutions corresponding to a D1-brane suspended between these D3 branes. We consider this problem in the zero slope limit where the tilt of the D3-branes is encoded in the uniform gradient of the adjoint scalar field. Such a system is closely related to the non-abelian flux background considered originally by van Baal. We provide three arguments supporting the existence of a single magnetic monopole solution. We also comment on the relation between our construction and a recent work by Mintun, Polchinski, and Sun.
The Spectrum of FZZT Branes Beyond the Planar Limit
Atkin, Max R
2010-01-01
Minimal string theory has a number of FZZT brane boundary states; one for each Cardy state of the minimal model. It was conjectured by Seiberg and Shih that all branes in a minimal string theory could be expressed as a linear combination of the brane associated to the identity operator of the minimal model with complex shifts in the boundary cosmological constant. Subsequently it was found that this identification of FZZT branes does not hold exactly for some cylinder amplitudes but was spoiled by terms that are associated with vanishing worldsheet area and are therefore non-universal. In this paper we investigate this claim for a number of more complicated amplitudes such as cylinders and discs-with-handle using both Liouville and matrix model methods. We find that the aforementioned identification of FZZT branes is spoiled by terms that do not admit an interpretation as non-universal terms. Furthermore, the spoiling terms as computed using the matrix model are found to be in agreement with those coming from...
Bounded Scalar Perturbations in Bouncing Brane World Cosmologies
Maier, Rodrigo; Soares, Ivano Damião
2013-01-01
We examine the dynamics of scalar perturbations in closed Friedmann-Lema\\^itre-Robertson- Walker (FLRW) universes in the framework of Brane World theory with a timelike extra dimension. In this scenario, the unperturbed Friedmann equations contain additional terms arising from the bulk-brane interaction that implement non-singular bounces in the models with a cosmological constant and non-interacting perfect fluids. The structure of the phase-space of the models allows for two basic configurations, namely, one bounce solutions or eternal universes. Assuming that the matter content of the model is given by dust and radiation, we derive the dynamical field equations for scalar hydrodynamical perturbations considering either a conformally flat (de Sitter) bulk or a perturbed bulk. We perform a numerical analysis which can shed some light on the study of cosmological scalar perturbations in bouncing brane world models. From a mathematical point of view we show that although the bounce enhances the amplitudes of s...
Tensor Perturbations from Brane-World Inflation with Curvature Effects
Bouhmadi-Lopez, Mariam; Izumi, Keisuke; Chen, Pisin
2013-01-01
The brane-world scenario provides an intriguing possibility to explore the phenomenological cosmology implied by string/M theory. In this paper, we consider a modified Randall-Sundrum single brane model with two natural generalizations: a Gauss-Bonnet term in the five-dimensional bulk action as well as an induced gravity term in the four-dimensional brane action, which are the leading-order corrections to the Randall-Sundrum model. We study the influence of these combined effects on the evolution of the primordial gravitational waves generated during an extreme slow-roll inflation on the brane. The background, for the early inflationary era, is then modeled through a de Sitter brane embedded within an anti-de Sitter bulk. In this framework, we show that both effects tend to suppress the Randall-Sundrum enhancement of the amplitude of the tensor perturbations at relatively high energies. Moreover, the Gauss-Bonnet effect, relative to standard general relativity, will abruptly enhance the tensor-to-scalar ratio...
Brane Effective Actions, Kappa-Symmetry and Applications
Directory of Open Access Journals (Sweden)
Joan Simón
2012-02-01
Full Text Available This is a review on brane effective actions, their symmetries and some of their applications. Its first part covers the Green–Schwarz formulation of single M- and D-brane effective actions focusing on kinematical aspects: the identification of their degrees of freedom, the importance of world volume diffeomorphisms and kappa symmetry to achieve manifest spacetime covariance and supersymmetry, and the explicit construction of such actions in arbitrary on-shell supergravity backgrounds. Its second part deals with applications. First, the use of kappa symmetry to determine supersymmetric world volume solitons. This includes their explicit construction in flat and curved backgrounds, their interpretation as Bogomol’nyi–Prasad–Sommerfield (BPS states carrying (topological charges in the supersymmetry algebra and the connection between supersymmetry and Hamiltonian BPS bounds. When available, I emphasise the use of these solitons as constituents in microscopic models of black holes. Second, the use of probe approximations to infer about the non-trivial dynamics of strongly-coupled gauge theories using the anti de Sitter/conformal field theory (AdS/CFT correspondence. This includes expectation values of Wilson loop operators, spectrum information and the general use of D-brane probes to approximate the dynamics of systems with small number of degrees of freedom interacting with larger systems allowing a dual gravitational description. Its final part briefly discusses effective actions for N D-branes and M2-branes. This includes both Super-Yang-Mills theories, their higher-order corrections and partial results in covariantising these couplings to curved backgrounds, and the more recent supersymmetric Chern–Simons matter theories describing M2-branes using field theory, brane constructions and 3-algebra considerations.
Anisotropy in Born-Infeld brane cosmology
Haghani, Z.; Sepangi, H. R.; shahidi, S.
2011-01-01
The accelerated expansion of the universe together with its present day isotropy has posed an interesting challenge to the numerous model theories presented over the years to describe them. In this paper, we address the above questions in the context of a brane-world model where the universe is filled with a Born-Infeld matter. We show that in such a model, the universe evolves from a highly anisotropic state to its present isotropic form which has entered an accelerated expanding phase.
Brane-world stars from minimal geometric deformation, and black holes
Casadio, Roberto
2012-01-01
We build analytical models of spherically symmetric stars in the brane-world, in which the external space-time contains both an ADM mass and a tidal charge. In order to determine the interior geometry, we apply the principle of minimal geometric deformation, which allows one to map General Relativistic solutions to solutions of the effective four-dimensional brane-world equations. We further restrict our analysis to stars with a radius linearly related to the total General Relativistic mass, and obtain a general relation between the latter, the brane-world ADM mass and the tidal charge. In these models, the value of the star's radius can then be taken to zero smoothly, thus obtaining brane-world black hole metrics with a tidal charge solely determined by the mass of the source and the brane tension. General conclusions regarding the minimum mass for semiclassical black holes will also be drawn.
D-brane physics. From weak to strong coupling
Energy Technology Data Exchange (ETDEWEB)
Vieira Lopes, Daniel Ordine
2013-01-10
In this thesis we discuss two aspects of branes relevant to high-energy phenomenology. First, we consider a single D6-brane wrapping a special Lagrangian cycle and the background space compactified in a Calabi-Yau orientifold the conditions needed to obtain a four-dimensional N=1 supersymmetric theory. We calculate the bosonic part of the effective action by performing a Kaluza-Klein reduction of the brane seven-dimensional action, and obtain the N=1 characteristic data. To discuss the moduli, we first fix the moduli from deformations of the background Calabi-Yau and study the D-brane deformation moduli space. We next allow for Calabi-Yau deformations, and show that the moduli space for complex structure deformations is corrected by the fields living on the D6-brane. We also calculate the scalar potential from D- and F-terms generated from brane and background configurations that would break the supersymmetry condition. We then, via Mirror Symmetry, relate the spectrum obtained in our work to the spectrum in Type IIB effective theory with D3- D5- and D7-branes, and we propose a Kaehler potential for the moduli space of brane deformations in Type IIB theories. In the second part of the thesis we discuss effects of brane intersections when the string coupling can become strong, and we work in the framework of F-theory. After reviewing the basics of F-theory constructions and a particular SU(5) model already discussed in the literature, we construct a model which contains a point of E{sub 8} singularity, and curves of E{sub 6} singularity. By explicitly resolving the space, we show that the resolution requires the introduction of higher dimensional fibers, and argue how we can circumvent this problem for the E{sub 6} curve, leading to the expected resolution that generate an E{sub 6} group, while at the E{sub 8} point we cannot make the resolution lead to an expected E{sub 8} structure.
Electric Polarization Induced by Gravity in Fat Branes
Dahia, F; Romero, C
2013-01-01
In the fat brane model, also known as the split fermion model, it is assumed that leptons and baryons live in different hypersurfaces of a thick brane in order to explain the proton stability without invoking any symmetry. It turns out that, in the presence of a gravity source $M$, particles will see different four-dimensional (4D) geometries and hence, from the point of view of 4D-observers, the equivalence principle will be violated. As a consequence, we show that a hydrogen atom in the gravitational field of $M$ will acquire a radial electric dipole. This effect is regulated by the Hamiltonian $H_{d}=-\\mu\\mathbf{A}\\cdot\\mathbf{\\delta r}$, which is the gravitational analog of the Stark Hamiltonian, where the electric field is replaced by the tidal acceleration $\\mathbf{A}$ due to the split of fermions in the brane and the atomic reduced mass $\\mu$ substitutes the electric charge.
Electric dipole induced by gravity in fat branes
Energy Technology Data Exchange (ETDEWEB)
Dahia, F. [Dep. of Physics, Univ. Fed. da Paraíba, João Pessoa, Paraíba (Brazil); Dep. of Physics, Univ. Fed. de Campina Grande, Campina Grande, Paraíba (Brazil); Albuquerque Silva, Alex de [Dep. of Physics, Univ. Fed. da Paraíba, João Pessoa, Paraíba (Brazil); Dep. of Physics, Univ. Fed. de Campina Grande, Sumé, Paraíba (Brazil); Romero, C. [Dep. of Physics, Univ. Fed. da Paraíba, João Pessoa, Paraíba (Brazil)
2014-05-01
In the fat brane model, also known as the split fermion model, it is assumed that leptons and baryons live in different hypersurfaces of a thick brane in order to explain the proton stability without invoking any symmetry. It turns out that, in the presence of a gravity source M, particles will see different four-dimensional (4D) geometries and hence, from the point of view of 4D-observers, the equivalence principle will be violated. As a consequence, we show that a hydrogen atom in the gravitational field of M will acquire a radial electric dipole. This effect is regulated by the Hamiltonian H{sub d}=−μA⋅δr, which is the gravitational analog of the Stark Hamiltonian, where the electric field is replaced by the tidal acceleration A due to the split of fermions in the brane and the atomic reduced mass μ substitutes the electric charge.
Warped Graviton Couplings to Bulk Vectors with Brane Kinetic Terms
Kobakhidze, Archil; Wu, Lei; Yue, Jason
2016-01-01
We consider non-universal couplings between Kaluza-Klein (KK) gravitons and bulk Standard Model (SM) vectors in the Randall-Sundrum (RS) model due to the inclusion of both UV and IR brane-localised gauge kinetic terms. We find that such kinetic terms can enhance the couplings of KK gravitons to SM gauge bosons and help ensure the KK vector masses are consistent with electroweak precision constraints. As an application, we consider the 750 GeV diphoton excess observed in the early LHC Run 2 data, identifying the lightest KK graviton with the diphoton resonance and employing brane kinetic terms to increase the coupling to SM vectors.
Lectures on string/brane cosmology
International Nuclear Information System (INIS)
An overview of some cosmological aspects of string theory is presented. Recent developments are emphasized, especially the attempts to derive inflation or alternatives to inflation from the dynamics of branes in string theory. Time-dependent backgrounds with potential cosmological implications, such as those provided by negative tension branes and S-branes and the rolling string tachyon are also discussed
Brane Baldness vs. Superselection Sectors
Marolf, D M; Marolf, Donald; Peet, Amanda W.
1999-01-01
The search for intersecting brane solutions in supergravity is a large and profitable industry. Recently, attention has focused on finding localized forms of known `delocalized' solutions. However, in some cases, a localized version of the delocalized solution simply does not exist. Instead, localized separated branes necessarily delocalize as the separation is removed. This phenomenon is related to black hole no-hair theorems, i.e. `baldness.' We continue the discussion of this effect and describe how it can be understood, in the case of Dirichlet branes, in terms of the corresponding intersection field theory. When it occurs, it is associated with the quantum mixing of phases and lack of superselection sectors in low dimensional field theories. We find surprisingly wide agreement between the field theory and supergravity both with respect to which examples delocalize and with respect to the rate at which this occurs.
Mkrtchyan, H G
2003-01-01
Little groups for preon branes (i.e. configurations of branes with maximal (n-1)/n fraction of survived supersymmetry) for dimensions d=2,3,...,11 are calculated for all massless, and partially for massive orbits. For massless orbits little groups are semidirect product of d-2 translational group $T_{d-2}$ on a subgroup of (SO(d-2) $\\times$ R-invariance) group. E.g. at d=9 the subgroup is exceptional $G_2$ group. It is also argued, that 11d Majorana spinor invariants, which distinguish orbits, are actually invariant under d=2+10 Lorentz group. Possible applications of these results include construction of field theories in generalized space-times with brane charges coordinates, different problems of group's representations decompositions, spin-statistics issues.
MKRTCHYAN, H.; MKRTCHYAN, R.
Little groups for preon branes (i.e. configurations of branes with maximal (n-1)/n fraction of survived supersymmetry) for dimensions d=2,3,…,11 are calculated for all massless, and partially for massive orbits. For massless orbits little groups are semidirect product of d-2 translational group Td-2 on a subgroup of (SO(d-2) × R-invariance) group. E.g. at d=9 the subgroup is exceptional G2 group. It is also argued, that 11D Majorana spinor invariants, which distinguish orbits, are actually invariant under d=2+10 Lorentz group. Possible applications of these results include construction of field theories in generalized spacetimes with brane charges coordinates, different problems of group's representations decompositions, spin-statistics issues.
Regular Bulk Solutions in Brane-Worlds with Inhomogeneous Dust and Generalized Dark Radiation
Directory of Open Access Journals (Sweden)
A. Herrera-Aguilar
2015-01-01
Full Text Available From the dynamics of a brane-world with matter fields present in the bulk, the bulk metric and the black string solution near the brane are generalized, when both the dynamics of inhomogeneous dust/generalized dark radiation on the brane-world and inhomogeneous dark radiation in the bulk as well are considered as exact dynamical collapse solutions. Based on the analysis on the inhomogeneous static exterior of a collapsing sphere of homogeneous dark radiation on the brane, the associated black string warped horizon is studied, as well as the 5D bulk metric near the brane. Moreover, the black string and the bulk are shown to be more regular upon time evolution, for suitable values for the dark radiation parameter in the model, by analyzing the soft physical singularities.
A Naturally Small Cosmological Constant on the Brane?
Burgess, C P; Quevedo, Fernando
2000-01-01
There appears to be no natural explanation for the cosmological constant's small size within the framework of local relativistic field theories. We argue that the recently-discussed framework for which the observable universe is identified with a p-brane embedded within a higher-dimensional `bulk' spacetime, has special properties that may help circumvent the obstacles to this understanding. This possibility arises partly due to several unique features of the brane proposal. These are: (1) the potential such models introduce for partially breaking supersymmetry, (2) the possibility of having low-energy degrees of freedom which are not observable to us because they are physically located on a different brane, (3) the fundamental scale may be much smaller than the Planck scale. Furthermore, although the resulting cosmological constant in the scenarios we outline is naturally suppressed by weak coupling constants of gravitational strength, it need not be exactly zero, raising the possibility it could be in the r...
Light-cone M5 and multiple M2-branes
Energy Technology Data Exchange (ETDEWEB)
Bandos, Igor A [Department of Theoretical Physics and History of Science, University of the Basque Country (EHU/UPV), PO Box 644, 48080 Bilbao (Spain); Townsend, Paul K [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)], E-mail: bandos@ific.uv.es, E-mail: p.k.townsend@damtp.cam.ac.uk
2008-12-21
We present the light-cone gauge fixed Lagrangian for the M5-brane; it has a residual 'exotic' gauge invariance with the group of 5-volume preserving diffeomorphisms, SDiff{sub 5}, as gauge group. For an M5-brane of topology R{sup 2}xM{sub 3}, for closed 3-manifold M{sub 3}, we find an infinite tension limit that yields an SO(8)-invariant (1 + 2)-dimensional field theory with 'exotic' SDiff{sub 3} gauge invariance. We show that this field theory is the Carrollian limit of the Nambu bracket realization of the 'BLG' model for multiple M2-branes.
Scalar brane backgrounds in higher order curvature gravity
Charmousis, C; Dufaux, J F; Charmousis, Christos; Davis, Stephen C.; Dufaux, Jean-Francois
2003-01-01
We investigate maximally symmetric brane world solutions with a scalar field. Five-dimensional bulk gravity is described by a general lagrangian which yields field equations containing no higher than second order derivatives. This includes the Gauss-Bonnet combination for the graviton. Stability and gravitational properties of such solutions are considered, and we particularily emphasise the modifications induced by the higher order terms. In particular it is shown that higher curvature corrections to Einstein theory can give rise to instabilities in brane world solutions. A method for analytically obtaining the general solution for such actions is outlined. Genericaly, the requirement of a finite volume element together with the absence of a naked singularity in the bulk imposes fine-tuning of the brane tension. A model with a moduli scalar field is analysed in detail and we address questions of instability and non-singular self-tuning solutions. In particular, we discuss a case with a normalisable zero mode...
Nernst branes with Lifshitz asymptotics in N=2 gauged supergravity
Cardoso, G L; Nampuri, S
2015-01-01
We discuss two classes of non-supersymmetric interpolating solutions in N=2, D=4 gauged supergravity, that flow from either a z=2 Lifshitz geometry or a conformal AdS background to the near-horizon geometry of a Nernst brane. We obtain these solutions by constructing a z=2 supersymmetric Lifshitz solution in the STU model from a first-order rewriting of the action, then lifting it up to a five-dimensional background and subsequently modifying this five-dimensional solution by a two-parameter family of deformations. Under reduction, these give four-dimensional non-supersymmetric Nernst brane solutions. This is a step towards resolving the Lifshitz tidal force singularity in the context of N=2 gauged supergravity and suggests an approach to encoding the Nernst brane in terms of the Schroedinger symmetry group of the holographically dual field theory.
Topological Insulators and Superconductors from D-branes
Ryu, Shinsei
2010-01-01
Realization of topological insulators (TIs) and superconductors (TSCs), such as the quantum spin Hall effect and the Z_2 topological insulator, in terms of D-branes in string theory is proposed. We establish a one-to-one correspondence between the K-theory classification of TIs/TSCs and D-brane charges. The string theory realization of TIs and TSCs comes naturally with gauge interactions, and the Wess-Zumino term of the D-branes gives rise to a gauge field theory of topological nature. This sheds light on TIs and TSCs beyond non-interacting systems, and the underlying topological field theory description thereof. In particular, our string theory realization includes the honeycomb lattice Kitaev model in two spatial dimensions, and its higher-dimensional extensions.
Lifshitz Hydrodynamics from Lifshitz Black Branes with Linear Momentum
Hartong, Jelle; Sanchioni, Marco
2016-01-01
We construct a new class of 4-dimensional z=2 Lifshitz black branes that have a nonzero linear momentum. These are solutions of an Einstein-Proca-dilaton model that can be obtained by Scherk-Schwarz circle reduction of AdS_5 gravity coupled to a free real scalar field. The boundary of a bulk Lifshitz space-time is a Newton-Cartan geometry. We show that the fluid dual to the moving Lifshitz black brane leads to a novel form of Lifshitz hydrodynamics on a Newton-Cartan space-time. Since the linear momentum of the black brane cannot be obtained by a boost transformation the velocity of the fluid or rather, by boundary rotational invariance, its magnitude plays the role of a chemical potential. The conjugate dual variable is mass density. The Lifshitz perfect fluid can be thought of as arising from a Schroedinger perfect fluid with broken particle number symmetry.
The fate of Newton's law in brane-world scenarios
International Nuclear Information System (INIS)
We consider brane-world scenarios embedded into string theory. We find that the D-brane backreaction induces a large increase in the open string's proper length. Consequently the stringy nature of elementary particles can be detected at distances much larger than the fundamental string scale. As an example, we compute the gravitational potential between two open strings ending on backreacting D3-branes in four-dimensional compactifications of type II string theory. We find that the Newtonian potential receives a correction that goes like 1/r but that is not proportional to the inertial masses of the open strings, implying a violation of the equivalence principle in the effective gravitational theory. This stringy correction is screened by thermal effects when the distance between the strings is greater than the inverse temperature. This suggests new experimental tests for many phenomenological models in type II string theory.
Cosmography of f(R) - brane cosmology
Bouhmadi-Lopez, Mariam; Cardone, Vincenzo F
2010-01-01
Cosmography is a useful tool to constrain cosmological models, in particular dark energy models. In the case of modified theories of gravity, where the equations of motion are generally quite complicated, cosmography can contribute to select realistic models without imposing arbitrary choices a priori. Indeed, its reliability is based on the assumptions that the universe is homogeneous and isotropic on large scale and luminosity distance can be "tracked" by the derivative series of the scale factor a(t). We apply this approach to induced gravity brane-world models where an f(R)-term is present in the brane effective action. The virtue of the model is to self-accelerate the normal and healthy DGP branch once the f(R)-term deviates from the Hilbert-Einstein action. We show that the model, coming from a fundamental theory, is consistent with the LCDM scenario at low redshift. We finally estimate the cosmographic parameters fitting the Union2 Type Ia Supernovae (SNeIa) dataset and the distance priors from Baryon ...
Nonabelian D-branes and Noncommutative Geometry
Myers, R C
2001-01-01
We discuss the nonabelian world-volume action which governs the dynamics of N coincident Dp-branes. In this theory, the branes' transverse displacements are described by matrix-valued scalar fields, and so this is a natural physical framework for the appearance of noncommutative geometry. One example is the dielectric effect by which Dp-branes may be polarized into a noncommutative geometry by external fields. Another example is the appearance of noncommutative geometries in the description of intersecting D-branes of differing dimensions, such as D-strings ending on a D3- or D5-brane. We also describe the related physics of giant gravitons.
Diffractions from the brane and GW150914
Gogberashvili, Merab
2016-01-01
In the braneworld scenario the zero mode gravitons are trapped on a brane due to non-linear warping effect, so that gravitational waves can reflect from the brane walls. If the reflected waves form an interference pattern on the brane then it can be detected on existing detectors due to spatial variations of intensity in the pattern. As an example we interpret the LIGO event GW150914 as a manifestation of such interference pattern produced by the burst gravitational waves, emitted by a powerful source inside or outside the brane and reflected from the brane walls.
On the spectral properties of multi-branes, M2 and M5 branes
Energy Technology Data Exchange (ETDEWEB)
Garcia del Moral, M.P. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo 18, 33007, Oviedo (Spain); Restuccia, A. [Departamento de Fisica, Universidad de Antofagasta, Aptdo 02800 (Chile); Departamento de Fisica, Universidad Simon Bolivar, Apartado 89000, Caracas 1080-A (Venezuela)
2011-07-01
In this note we summarize some of the properties found in [1-3]. We characterize spectral properties of the quantum mechanical hamiltonian of theories with fermionic degrees of freedom beyond semiclassical approximation. We obtain a general class of bosonic polynomial potentials for which the Schroeedinger operator has a discrete spectrum. This class includes all the scalar potentials in membrane, 5-brane, p-branes, multiple M2 branes, BLG and ABJM theories. We also give a sufficient condition for discreteness of the spectrum for supersymmmetric and non supersymmetric theories with a fermionic contribution. We characterize then the spectral properties of different theories: the BMN matrix model, the supermembrane with central charges and a bound state of N D2 with m D0. We show that, while the first two models have a purely discrete spectrum with finite multiplicity, the latter has a continuous spectrum starting from a constant given in terms of the monopole charge. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Linearized gravity in flat braneworlds with anisotropic brane tension
Ito, M
2002-01-01
We study the four-dimensional gravitational fluctuation on anisotropic brane tension embedded in braneworlds with vanishing bulk cosmological constant. In this setup, warp factors have two types (A and B) and we point out that the two types correspond to positive and negative tension brane, respectively. We show that volcano potential in the model of type A has singularity and the usual Newton's law is reproduced by the existence of normalizable zero mode. While, in the case of type B, the effective Planck scale is infinite so that there is no normalizable zero mode.
Variable-speed-of-light cosmology from brane world scenario
International Nuclear Information System (INIS)
We argue that the four-dimensional universe on the TeV brane of the Randall-Sundrum scenario takes the bimetric structure of Clayton and Moffat, with gravitons traveling faster than photons instead, while the radion varies with time. We show that such brane world bimetric model can thereby solve the flatness and the cosmological constant problems, provided the speed of a graviton decreases to the present day value rapidly enough. The resolution of other cosmological problems such as the horizon problem and the monopole problem requires supplementation by inflation, which may be achieved by the radion field provided the radion potential satisfies the slow-roll approximation. (author)
Accelerating universe in brane gravity with a confining potential
Energy Technology Data Exchange (ETDEWEB)
Heydari-Fard, M. [Department of Physics, Shahid Beheshti University, Evin, Tehran 19839 (Iran, Islamic Republic of); Shirazi, M. [Department of Physics, Shahid Beheshti University, Evin, Tehran 19839 (Iran, Islamic Republic of); Jalalzadeh, S. [Department of Physics, Shahid Beheshti University, Evin, Tehran 19839 (Iran, Islamic Republic of)]. E-mail: s-jalalzadeh@sbu.ac.ir; Sepangi, H.R. [Department of Physics, Shahid Beheshti University, Evin, Tehran 19839 (Iran, Islamic Republic of)]. E-mail: hr-sepangi@sbu.ac.ir
2006-08-31
We construct the Einstein field equations on a 4-dimensional brane embedded in an m-dimensional bulk where the matter fields are confined to the brane by means of a confining potential. As a result, an extra term in the Friedmann equation in a m-dimensional bulk appears that may be interpreted as the X-matter, providing a possible phenomenological explanation for the acceleration of the universe. The study of the relevant observational data suggests good agreement with the predictions of this model.
Accelerating universe in brane gravity with a confining potential
Heydari-Fard, M; Sepangi, H R; Shirazi, M
2006-01-01
We construct the Einstein field equations on a 4-dimensional brane embedded in an $m$-dimensional bulk where the matter fields are confined to the brane by means of a confining potential. As a result, an extra term in the Friedmann equation in a $m$-dimensional bulk appears that may be interpreted as the X-matter, providing a possible phenomenological explanation for the acceleration of the universe. The study of the relevant observational data suggests good agreement with the predictions of this model.
Gravity and antigravity in a brane world with metastable gravitons
Gregory, R.; Rubakov, V. A.; Sibiryakov, S. M.
2000-09-01
In the framework of a five-dimensional three-brane model with quasi-localized gravitons we evaluate metric perturbations induced on the positive tension brane by matter residing thereon. We find that at intermediate distances, the effective four-dimensional theory coincides, up to small corrections, with General Relativity. This is in accord with Csaki, Erlich and Hollowood and in contrast to Dvali, Gabadadze and Porrati. We show, however, that at ultra-large distances this effective four-dimensional theory becomes dramatically different: conventional tensor gravity changes into scalar anti-gravity.
Brane and Wormhole in Baby Universe
Naboulsi, R
2003-01-01
In this paper we search the minimal conditions for the creation of a Universe from a Tolman wormhole `bounce' from a previous collapse without passing by an initial singularity. Inspired from brane cosmology, the total density is taken to be the sum of the ordinary matter and time-decreasing exotic matter, as well as time-decreasing cosmological constant. We show that these later didn't affect the standard point-wise energy conditions and that there is always an open region surrounding the bounce over which the strong energy condition must be violated. Flat and hyperbolic spatial Universes are not permitted in our model.
Energy Technology Data Exchange (ETDEWEB)
Horowitz, Gary; /UC, Santa Barbara; Lawrence, Albion; /Brandeis U. /Santa Barbara, KITP; Silverstein, Eva; /SLAC /Stanford U., Phys. Dept. /Santa Barbara, KITP
2010-08-26
We study a simple model of a black hole in AdS and obtain a holographic description of the region inside the horizon. A key role is played by the dynamics of the scalar fields in the dual gauge theory. This leads to a proposal for a dual description of D-branes falling through the horizon of any AdS black hole. The proposal uses a field-dependent time reparameterization in the field theory. We relate this reparametrization to various gauge invariances of the theory. Finally, we speculate on information loss and the black hole singularity in this context.
Gravity on codimension 2 brane worlds
Energy Technology Data Exchange (ETDEWEB)
Navarro, Ignacio; /Durham U., IPPP; Santiago, Jose; /Durham U., IPPP /Fermilab
2004-11-01
The authors compute the matching conditions for a general thick codimension 2 brane, a necessary previous step towards the investigation of gravitational phenomena in co-dimension 2 braneworlds. They show that, provided the brane is weakly curved, they are specified by the integral in the extra dimensions of the brane energy-momentum, independently of its detailed internal structure. These general matching conditions can then be used as boundary conditions for the bulk solution. By evaluating Einstein equations at the brane boundary they are able to write an evolution equation for the induced metric on the brane depending only on physical brane parameters and the bulk energy-momentum tensor. They particularize to a cosmological metric and show that a realistic cosmology can be obtained in the simplest case of having just a non-zero cosmological constant in the bulk. They point out several parallelisms between this case and the codimension 1 brane worlds in an AdS space.
Universality in D-brane inflation
International Nuclear Information System (INIS)
We study the six-field dynamics of D3-brane inflation for a general scalar potential on the conifold, finding simple, universal behavior. We numerically evolve the equations of motion for an ensemble of more than 7·107 realizations, drawing the coefficients in the scalar potential from statistical distributions whose detailed properties have demonstrably small effects on our results. When prolonged inflation occurs, it has a characteristic form: the D3-brane initially moves rapidly in the angular directions, spirals down to an inflection point in the potential, and settles into single-field inflation. The probability of Ne e-folds of inflation is a power law, P(Ne)∝Ne−3, and we derive the same exponent from a simple analytical model. The success of inflation is relatively insensitive to the initial position: we find attractor behavior in the angular directions, and the D3-brane can begin far above the inflection point without overshooting. Initial radial or angular velocities, on the other hand, can have a significant effect on the duration of inflation. In favorable regions of the spaces of initial velocities and of Lagrangian parameters, models yielding 60 e-folds of expansion arise approximately once in 103 trials. Realizations that are effectively single-field and give rise to a primordial spectrum of fluctuations consistent with WMAP, for which at least 120 e-folds are required, arise approximately once in 105 trials. The emergence of robust predictions from a six-field potential with hundreds of terms invites an analytic approach to multifield inflation
750 GeV Diphotons from a D3-brane
Heckman, Jonathan J
2015-01-01
Motivated by the recently reported diphoton excess at 750 GeV observed by both CMS and ATLAS, we study string-based particle physics models which can accommodate this signal. Quite remarkably, although Grand Unified Theories in F-theory tend to impose tight restrictions on candidate extra sectors, the case of a probe D3-brane near an E-type Yukawa point naturally leads to a class of strongly coupled models capable of accommodating the observed signature. In these models, the visible sector is realized by intersecting 7-branes, and the 750 GeV resonance is a scalar modulus associated with motion of the D3-brane in the direction transverse to the Standard Model 7-branes. Integrating out heavy 3-7 string messenger states leads to dimension five operators for gluon fusion production and diphoton decays. Due to the unified structure of interactions, these models also predict that there should be additional decay channels to ZZ and Z gamma. We also comment on models with distorted unification, where both the produc...
750 GeV diphotons from a D3-brane
Heckman, Jonathan J.
2016-05-01
Motivated by the recently reported diphoton excess at 750 GeV observed by both CMS and ATLAS, we study string-based particle physics models which can accommodate this signal. Quite remarkably, although Grand Unified Theories in F-theory tend to impose tight restrictions on candidate extra sectors, the case of a probe D3-brane near an E-type Yukawa point naturally leads to a class of strongly coupled models capable of accommodating the observed signature. In these models, the visible sector is realized by intersecting 7-branes, and the 750 GeV resonance is a scalar modulus associated with motion of the D3-brane in the direction transverse to the Standard Model 7-branes. Integrating out heavy 3-7 string messenger states leads to dimension five operators for gluon fusion production and diphoton decays. Due to the unified structure of interactions, these models also predict that there should be additional decay channels to ZZ and Zγ. We also comment on models with distorted unification, where both the production mechanism and decay channels can differ.
750 GeV diphotons from a D3-brane
Directory of Open Access Journals (Sweden)
Jonathan J. Heckman
2016-05-01
Full Text Available Motivated by the recently reported diphoton excess at 750 GeV observed by both CMS and ATLAS, we study string-based particle physics models which can accommodate this signal. Quite remarkably, although Grand Unified Theories in F-theory tend to impose tight restrictions on candidate extra sectors, the case of a probe D3-brane near an E-type Yukawa point naturally leads to a class of strongly coupled models capable of accommodating the observed signature. In these models, the visible sector is realized by intersecting 7-branes, and the 750 GeV resonance is a scalar modulus associated with motion of the D3-brane in the direction transverse to the Standard Model 7-branes. Integrating out heavy 3–7 string messenger states leads to dimension five operators for gluon fusion production and diphoton decays. Due to the unified structure of interactions, these models also predict that there should be additional decay channels to ZZ and Zγ. We also comment on models with distorted unification, where both the production mechanism and decay channels can differ.
Self-accelerated brane Universe with warped extra dimension
Gorbunov, D S
2008-01-01
We propose a cosmological model which exhibits the phenomenon of self-acceleration: the Universe is attracted to the phase of accelerated expansion at late times even in the absence of the cosmological constant. The self-acceleration is inevitable in the sense that it cannot be neutralized by any negative explicit cosmological constant. The model is formulated in the framework of brane-world theories with a warped extra dimension. The key ingredient of the model is the brane-bulk energy transfer which is carried by bulk vector fields with a sigma-model-like boundary condition on the brane. We explicitly find the 5-dimensional metric corresponding to the late-time de Sitter expansion on the brane; this metric describes an AdS_5 black hole with growing mass. The present value of the Hubble parameter implies the scale of new physics of order 1 TeV, where the proposed model has to be replaced by putative UV-completion. The mechanism leading to the self-acceleration has AdS/CFT interpretation as occurring due to s...
Branes, weights and central charges
Bergshoeff, Eric A.; Riccioni, Fabio; Romano, Luca
2013-01-01
We study the properties of half-supersymmetric branes in string theory with 32 supercharges from a purely group-theoretical point of view using the U-duality symmetry of maximal supergravity and the R-symmetry of the corresponding supersymmetry algebra. In particular, we show that half-supersymmetri
AdS/CFT correspondence and coincident D-6-branes
Ketov, Sergei V.
1998-01-01
A relation between confinement and Maldacena conjecture is briefly discussed. The gauge symmetry enhancement for two coincident D-6-branes is analyzed from the viewpoint of the hypermultiplet low-energy effective action given by the N=2 supersymmetric non-linear sigma-model with the Eguchi-Hanson (ALE) target space.
Anomalies and inflow on D-branes and O-planes
Scrucca, Claudio A; Scrucca, Claudio A.; Serone, Marco
1999-01-01
We derive the general form of the anomaly for chiral spinors and self-dual antisymmetric tensors living on D-brane and O-plane interesections, using both path-integral and index theorem methods. We then show that the anomalous couplings to RR forms of D-branes and O-planes in a general background are precisely those required to cancel these anomalies through the inflow mechanism. This allows, for instance, for local anomaly cancellation in generic orientifold models, the relevant Green-Schwarz term being given by the sum of the anomalous couplings of all the D-branes and O-planes in the model.
Topics in brane world and quantum field theory
Corradini, Olindo
In the first part of the thesis we study various issues in the Brane World scenario with particular emphasis on gravity and the cosmological constant problem. First, we study localization of gravity on smooth domain-wall solutions of gravity coupled to a scalar field. In this context we discuss how the aforementioned localization is affected by including higher curvature terms in the theory, pointing out among other things that, general combinations of such terms lead to delocalization of gravity with the only exception of the Gauss-Bonnet combination (and its higher dimensional counterparts). We then find a solitonic 3-brane solution in 6D bulk in the Einstein-Hilbert-Gauss-Bonnet theory of gravity. Near to the brane the metric is that for a product of the 4D flat Minkowski space with a 2D wedge whose deficit angle is proportional to the brane tension. Consistency tests imposed on such backgrounds appear to require the localized matter on the brane to be conformal. We then move onto infinite volume extra dimension Brane World scenarios where we study gravity in a codimension-2 model, generalizing the work of Dvali, Gabadadze and Porrati to tensionful branes. We point out that, in the presence of the bulk Gauss-Bonnet combination, the Einstein-Hilbert term is induced on the brane already at the classical level. Consistency tests are presented here as well. To conclude we discuss, using String Theory, an interesting class of large-N gauge theories which have vanishing energy density even though these theories are non-covariant and non-supersymmetric. In the second part of the thesis we study a formulation of Quantum Mechanical Path Integrals in curved space. Such Path Integrals present superficial divergences which need to be regulated. We perform a three-loop calculation in mode regularization as a nontrivial check of the non-covariant counterterms required by such scheme. We discover that dimensional regularization can be successfully adopted to evaluate the
Cook, Paul P
2016-01-01
We investigate two-parameter solutions of sigma-models on two dimensional symmetric spaces contained in E11. Embedding such sigma-model solutions in space-time gives solutions of M* and M'-theory where the metric depends on general travelling wave functions, as opposed to harmonic functions typical in general relativity, supergravity and M-theory. Weyl reflection allows such solutions to be mapped to M-theory solutions where the wave functions depend explicitly on extra coordinates contained in the fundamental representation of E11.
Sound waves in the compactified D0-D4 brane system
Cai, Wenhe
2016-01-01
As an extension to our previous work, we study the transport properties of the Witten-Sakai-Sugimoto model in the black D4-brane background with smeared D0-branes (D0-D4/D8 system). Because of the presence of the D0-branes, this model is holographically dual to 4d QCD or Yang-Mills theory with a Chern-Simons term in the bubble configuration. And the number density of the D0-branes corresponds to the coupling constant ($\\theta$ angle) of the Chern-Simons term in the dual field theory. In this paper, we accordingly focus on small number density of the D0-branes to study the sound mode in the black D0-D4 brane system since the coupling of the Chern-Simons term should be quite weak in QCD. Then we derive its 5d effective theory and analytically compute the speed of sound and the sound wave attenuation in the approach of Gauge/Gravity duality. Our result shows the speed of sound and the sound wave attenuation is modified by the presence of the D0-branes. Thus they depend on the $\\theta$ angle or chiral potential i...
Penrose Limits of Branes and Marginal Intersecting Branes
Ryang, S
2003-01-01
We construct the Penrose limit backgrounds in closed forms along the generic null geodesics for the near-horizon geometries of D1, D3, D5, NS1 and NS5 branes. The Penrose limit metrics of D1, D5 and NS1 have non-trivial dependence of the light-cone time coordinate, while those of D3 and NS5 have no its dependence. We study the Penrose limits on the marginal 1/4 supersymmetric configurations of standard intersecting branes, such as the NS-NS intersection of NS1 and NS5, the R-R intersections of Dp and Dq over some spatial dimensions and the mix intersections of NS5 and Dp over (p -1)-dimensional spaces. They are classified into three types that correspond to the Penrose limits of D1, D3 and D5 backgrounds.
Schwarzschild black branes and strings in higher-dimensional brane worlds
International Nuclear Information System (INIS)
We consider branes embedded in spacetimes of codimension 1 and 2, with a warped metric tensor for the subspace parallel to the brane. We study a variety of brane-world solutions arising by introducing a Schwarzschild-like black hole metric on the brane and we investigate the properties of the corresponding higher-dimensional spacetime. We demonstrate that normalizable bulk modes lead to a vanishing flow of energy through the naked singularities. From this point of view, these singularities are harmless
BPS preons and tensionless super-p-brane in generalized superspace
Bandos, I A
2003-01-01
Tensionless super-p-branes in a generalized superspace with additional tensorial central charge coordinates might provide an extended object model for BPS preons, i.e. for hypothetical constituents of M-theory preserving 31 of 32 supersymmeties.
Classical tests of General Relativity in thick branes
Dahia, F.; de Albuquerque Silva, Alex
2015-02-01
Classical tests of General Relativity in braneworld scenarios have been investigated recently with the purpose of posing observational constraints on the parameters of some models of infinitely thin brane. Here we consider the motion of test particles in a thick brane scenario that corresponds to a regularized version of the Garriga-Tanaka solution, which describes a black hole solution in RSII model, in the weak field regime. By adapting a mechanism previously formulated in order to describe the confinement of massive tests particles in a domain wall (which simulates classically the trapping of the Dirac field in a domain wall), we study the influence of the brane thickness on the four-dimensional (4D) path of massless particles. Although the geometry is not warped and, therefore, the bound motion in the transverse direction is not decoupled from the movement in the 4D-world, we can find an explicit solution for the light deflection and the time delay, if the motion in the fifth direction is a high frequency oscillation. We verify that, owing to the transverse motion, the light deflection and the time delay depend on the energy of the light rays. This feature may lead to the phenomenon of gravitational rainbow. We also consider the problem from a semi-classical perspective, investigating the effects of the brane thickness on the motion of the zero-mode in the 4D-world.
Classical tests of General Relativity in thick branes
International Nuclear Information System (INIS)
Classical tests of General Relativity in braneworld scenarios have been investigated recently with the purpose of posing observational constraints on the parameters of some models of infinitely thin brane. Here we consider the motion of test particles in a thick brane scenario that corresponds to a regularized version of the Garriga-Tanaka solution, which describes a black hole solution in RSII model, in the weak field regime. By adapting a mechanism previously formulated in order to describe the confinement of massive tests particles in a domain wall (which simulates classically the trapping of the Dirac field in a domain wall), we study the influence of the brane thickness on the four-dimensional (4D) path of massless particles. Although the geometry is not warped and, therefore, the bound motion in the transverse direction is not decoupled from the movement in the 4D-world, we can find an explicit solution for the light deflection and the time delay, if the motion in the fifth direction is a high frequency oscillation. We verify that, owing to the transverse motion, the light deflection and the time delay depend on the energy of the light rays. This feature may lead to the phenomenon of gravitational rainbow. We also consider the problem from a semi-classical perspective, investigating the effects of the brane thickness on the motion of the zero-mode in the 4D-world. (orig.)
Classical tests of General Relativity in thick branes
Energy Technology Data Exchange (ETDEWEB)
Dahia, F. [Univ. Fed. da Paraiba, Department of Physics, Joao Pessoa, Paraiba (Brazil); Albuquerque Silva, Alex de [Univ. Fed. de Campina Grande, Department of Physics, Sume, Paraiba (Brazil)
2015-02-01
Classical tests of General Relativity in braneworld scenarios have been investigated recently with the purpose of posing observational constraints on the parameters of some models of infinitely thin brane. Here we consider the motion of test particles in a thick brane scenario that corresponds to a regularized version of the Garriga-Tanaka solution, which describes a black hole solution in RSII model, in the weak field regime. By adapting a mechanism previously formulated in order to describe the confinement of massive tests particles in a domain wall (which simulates classically the trapping of the Dirac field in a domain wall), we study the influence of the brane thickness on the four-dimensional (4D) path of massless particles. Although the geometry is not warped and, therefore, the bound motion in the transverse direction is not decoupled from the movement in the 4D-world, we can find an explicit solution for the light deflection and the time delay, if the motion in the fifth direction is a high frequency oscillation. We verify that, owing to the transverse motion, the light deflection and the time delay depend on the energy of the light rays. This feature may lead to the phenomenon of gravitational rainbow. We also consider the problem from a semi-classical perspective, investigating the effects of the brane thickness on the motion of the zero-mode in the 4D-world. (orig.)
Prospects of inflation in delicate D-brane cosmology
Panda, Sudhakar; Tsujikawa, Shinji
2007-01-01
We study D-brane inflation in a warped conifold background that includes brane-position dependent corrections for the nonperturbative superpotential. Instead of stabilizing the volume modulus chi at instantaneous minima of the potential and studying the inflation dynamics with an effective single field (radial distance between a brane and an anti-brane) phi, we investigate the multi-field inflation scenario involving these two fields. The two-field dynamics with the potential V(phi,chi) in this model is significantly different from the effective single-field description in terms of the field phi when the field chi is integrated out. The latter picture underestimates the total number of e-foldings even by one order of magnitude. We show that a correct single-field description is provided by a field psi obtained from a rotation in the two-field space along the background trajectory. This model can give a large number of e-foldings required to solve flatness and horizon problems at the expense of fine-tunings of...
Gauge field localization on brane worlds
Guerrero, Rommel; Pantoja, Nelson; Rodriguez, R Omar
2009-01-01
We consider the effects of spacetime curvature and brane thickness on the localization of gauge fields on a brane via kinetic terms induced by localized fermions. We find that in a warped geometry with and infinitely thin brane, both the infrared and the ultraviolet behavior of the electromagnetic propagator are affected, providing a more stringent bound on the brane's tension than that coming from the requirement of four-dimensional gravity on the brane. On the other hand, for a thick wall in a flat spacetime, where the fermions are localized by means of a Yukawa coupling, we find that 4-dimensional electromagnetism is recovered in a region bounded from above by the same critical distance appearing in the thin case, but also from below by a new scale related to the brane's thickness and the electromagnetic couplings.
Cosmological Spacetimes from Negative Tension Brane Backgrounds
Burgess, C P; Rey, S J; Tasinato, G
2002-01-01
We put forward a viable nonsingular cosmology emerging out of negative-tension branes. The cosmology is based on a general class of solutions in Einstein-dilaton-Maxwell theory, presented in {\\tt hep-th/0106120}. We argue that solutions with hyperbolic or planar symmetry describe gravitational interactions due to a pair of negative-tension $q$-branes. These spacetimes are static near each brane, but become time-dependent and expanding at late times -- in some cases asymptotically approaching flat space. We interpret this expansion as being the spacetime's response to the branes presence. The time-dependent regions provide explicit realizations of cosmological spacetimes having past horizons without naked past singularities, and the past horizons are reminiscent of the S-brane solutions. We prove that the singularities in the static regions are repulsive to timelike geodesics, extract a cosmological `bounce' interpretation, compute the explicit charge and tension of the branes, analyse the classical stability ...
Brane plus Bulk Supersymmetry in Ten Dimensions
Bergshoeff, E A; Ortín, Tomas; Roest, D; Van Proeyen, A
2001-01-01
We discuss a generalized form of IIA/IIB supergravity depending on all R-R potentials C^(p) (p=0,1,...,9) as the effective field theory of Type IIA/IIB superstring theory. For the IIA case we explicitly break this R-R democracy to either p=5 which allows us to write a new bulk action that can be coupled to N=1 supersymmetric brane actions. The case of 8-branes is studied in detail using the new bulk & brane action. The supersymmetric negative tension branes without matter excitations can be viewed as orientifolds in the effective action. These D8-branes and O8-planes are fundamental in Type I' string theory. A BPS 8-brane solution is given which satisfies the jump conditions on the wall. As an application of our results we derive a quantization of the mass parameter and the cosmological constant in string units.
Supersymmetry and Wrapped Branes in Microstate Geometries
Tyukov, Alexander
2016-01-01
We consider the supergravity back-reaction of M2 branes wrapping around the space-time cycles in 1/8-BPS microstate geometries. We show that such brane wrappings will generically break all the supersymmetries. In particular, all the supersymmetries will be broken if there are such wrapped branes but the net charge of the wrapped branes is zero. We show that if M2 branes wrap a single cycle, or if they wrap a several of co-linear cycles with the same orientation, then the solution will be 1/16-BPS, having two supersymmetries. We comment on how these results relate to using W-branes to understand the microstate structure of 1/8-BPS black holes.
Stability of the graviton Bose-Einstein condensate in the brane-world
Casadio, Roberto
2016-01-01
We consider a solution of the effective four-dimensional Einstein equations, obtained from the general relativistic Schwarzschild metric through the principle of Minimal Geometric Deformation (MGD). Since the brane tension can, in general, introduce new singularities on a relativistic E\\"otv\\"os brane model in the MGD framework, we require the absence of observed singularities, in order to constrain the brane tension. We then study the corresponding Bose-Einstein condensate (BEC) gravitational system and determine the critical stability region of BEC MGD stellar configurations. Finally, the critical stellar densities are shown to be related with critical points of the information entropy.
Meta-Stable Brane Configurations by Quartic Superpotential for Bifundamentals
Ahn, Changhyun
The type IIA nonsupersymmetric meta-stable brane configuration consisting of three NS5-branes, D4-branes and anti-D4-branes where the electric gauge theory superpotential has a quartic term for the bifundamentals besides a mass term is constructed. By adding the orientifold 4-plane and 6-plane to this brane configuration, we also describe the intersecting brane configurations of type IIA string theory corresponding to the meta-stable nonsupersymmetric vacua of corresponding gauge theories.
Cosmology from quantum potential in brane-anti-brane system
Sepehri, Alireza
2015-01-01
Recently, some authors removed the big-bang singularity and predicted an infinite age of our universe. In this paper, we show that the same result can be obtained in string theory and M-theory; however, the shape of universe changes in different epochs. In our mechanism, first, N fundamental string decay to N D0-anti-D0-brane. Then, D0-branes join to each other, grow and and form a six-dimensional brane-antibrane system. This system is unstable, broken and present form of four dimensional universes , one anti-universe in additional to one wormhole are produced. Thus, there isn't any big-bang in cosmology and universe is a fundamental string at the beginning. Also, total age of universe contains two parts, one in related to initial age and second which is corresponded to present age of universe ($t_{tot}=t_{initial}+t_{present}$). On the other hand, initial age of universe includes two parts, the age of fundamental string and time of transition ($t_{initial}=t_{transition}+t_{f-string}$). We observe that only ...
Supersymmetric solutions of supergravity from wrapped branes
Paredes, A
2004-01-01
We consider several solutions of supergravity with reduced supersymmetry which are related to wrapped branes, and elaborate on their geometrical and physical interpretation. The Killing spinors are computed for each configuration. In particular, all the known metrics on the conifold and all G_2 holonomy metrics with cohomogeneity one and S^3xS^3 principal orbits are constructed from D=8 gauged supergravity in a unified formalism. The addition of 4-form fluxes piercing the unwrapped directions is also considered. We also study the problem of finding kappa-symmetric D5-probes in the so-called Maldacena-Nunez model. Some of these solutions are related to the addition of flavor to the dual gauge theory. We match our results with some known features of N=1 SQCD with a small number of flavors and compute its meson mass spectrum. Moreover, the gravity solution dual to three dimensional N=1 gauge theory, solutions related to branes wrapping hyperbolic spaces, Spin(7) holonomy metrics and SO(4) twistings in D=7 gauged...
Sarrazin, Michael
2014-01-01
It is suggested that two turbostratic graphene layers can be described through a formalism previously introduced for the study of braneworlds in high energy physics. It is demonstrated that any graphene bilayer can be conveniently described as a noncommutative two-sheeted (2+1) spacetime. The model Hamiltonian contains a coupling term connecting the two layers which is a reminiscent of the coupling which may exist between two braneworlds at a quantum level. In the present case, this term is related to a K-K' intervalley coupling. Phenomenological consequences are emphasized such as exciton swapping between the two graphene sheets. An experimental device is suggested to study this possible new effect. If demonstrated, this effet could lead to new technological applications. Incidentally, this demonstration could be also an indirect way to test the braneworld hypothesis.
Minimal D = 7 supergravity and the supersymmetry of Arnold-Beltrami flux branes
Fré, P.; Grassi, P. A.; Ravera, L.; Trigiante, M.
2016-06-01
In this paper we study some properties of the newly found Arnold-Beltrami flux-brane solutions to the minimal D = 7 supergravity. To this end we first single out the appropriate Free Differential Algebra containing both a gauge 3-form B [3] and a gauge 2-form B [2]: then we present the complete rheonomic parametrization of all the generalized curvatures. This allows us to identify two-brane configurations with Arnold-Beltrami fluxes in the transverse space with exact solutions of supergravity and to analyze the Killing spinor equation in their background. We find that there is no preserved supersymmetry if there are no additional translational Killing vectors. Guided by this principle we explicitly construct Arnold-Beltrami flux two-branes that preserve 0, 1/8 and 1/4 of the original supersymmetry. Two-branes without fluxes are instead BPS states and preserve 1/2 supersymmetry. For each two-brane solution we carefully study its discrete symmetry that is always given by some appropriate crystallographic group Γ. Such symmetry groups Γ are transmitted to the D = 3 gauge theories on the brane world-volume that would occur in the gauge/gravity correspondence. Furthermore we illustrate the intriguing relation between gauge fluxes in two-brane solutions and hyperinstantons in D = 4 topological sigma-models.
Black hole microstates from branes at angle
Pieri, Lorenzo
2016-01-01
We derive the leading g_s perturbation of the SUGRA fields generated by a supersymmetric configuration of respectively 1, 2 or 4 D3-branes intersecting at an arbitrary angle via the computation of the string theory disk scattering amplitude of one massless NSNS field interacting with open strings stretched between the branes. The configuration with four branes is expected to be relevant for black hole microstate counting in four dimensions.
Consistent Linearized Gravity in Brane Backgrounds
Aref'eva, I Ya; Mück, W; Viswanathan, K S; Volovich, I V
2000-01-01
A globally consistent treatment of linearized gravity in the Randall-Sundrum background with matter on the brane is formulated. Using a novel gauge, in which the transverse components of the metric are non-vanishing, the brane is kept straight. We analyze the gauge symmetries and identify the physical degrees of freedom of gravity. Our results underline the necessity for non-gravitational confinement of matter to the brane.
Coupling brane fields to bulk supergravity
Energy Technology Data Exchange (ETDEWEB)
Parameswaran, Susha L. [Uppsala Univ. (Sweden). Theoretical Physics; Schmidt, Jonas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2010-12-15
In this note we present a simple, general prescription for coupling brane localized fields to bulk supergravity. We illustrate the procedure by considering 6D N=2 bulk supergravity on a 2D orbifold, with brane fields localized at the fixed points. The resulting action enjoys the full 6D N=2 symmetries in the bulk, and those of 4D N=1 supergravity at the brane positions. (orig.)
Coupling brane fields to bulk supergravity
International Nuclear Information System (INIS)
In this note we present a simple, general prescription for coupling brane localized fields to bulk supergravity. We illustrate the procedure by considering 6D N=2 bulk supergravity on a 2D orbifold, with brane fields localized at the fixed points. The resulting action enjoys the full 6D N=2 symmetries in the bulk, and those of 4D N=1 supergravity at the brane positions. (orig.)
Three-branes in twelve dimensions
Hewson, S F
1999-01-01
In this note we discuss the theory of super-threebranes in a spacetime of signature (10,2). Upon reduction, the threebrane provides us with the classical representations of the M-2-brane and the type IIB superstring. Many features of the original super (2+2)-brane theory are clarified. In particular, the (10,2) superspace and the spinors required to construct the brane action are discussed.
Natural inflation and electroweak baryogenesis on the brane
Videla, Nelson
2016-01-01
In the present work we have studied natural inflation in the framework of the Randall-Sundrum II brane model (RS-II) in the light of the recent Planck results. Adopting the Randall-Sundrum fine-tuning, the model is characterized by 3 parameters in total, namely the 5-dimensional Planck mass and the mass scales of the inflaton potential. We show in the $n_s-r$ plane the theoretical predictions of the model together with the allowed contour plots, and we conclude that the model is viable. It is known that in the considered brane model electroweak baryogenesis can work for a suitable window of the five-dimensional Planck mass. By combining natural inflation with electroweak baryogenesis we determine the allowed range of all three parameters of the model for which a viable inflationary model can be obtained and at the same electroweak baryogenesis can work.
Branes constrictions with White Dwarfs
Garcia-Aspeitia, Miguel A
2015-01-01
We consider here a robust study of stellar dynamics for White Dwarf Stars with polytropic matter in the weak field approximation using the Lane-Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze its stability and compactness, in order to show whether it is possible to be close to the conventional wisdom of white dwarfs dynamics. Our results predicts an average value of brane tension as: $\\langle\\lambda\\rangle\\gtrsim84.818\\;\\rm MeV^4$, with a standard deviation $\\sigma\\simeq82.021\\;\\rm MeV^4$ which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining above of cosmological results provided by nucleosynthesis among others.
Brain Content of Branes' States
Mkrtchyan, R L
2003-01-01
The problem of decomposition of unitary irreps of (super) tensorial (i.e. extended with tensorial charges) Poincare algebra w.r.t. its different subgroups is considered. This requires calculation of little groups for different configurations of tensor charges. Particularly, for preon states (i.e. states with maximal supersymmetry) in different dimensions the particle content is calculated, i.e. the spectrum of usual Poincare representations in the preon representation of tensorial Poincare. At d=4 results coincide with (and may provide another point of view on) the Vasiliev's results in field theories in generalized space-time. The translational subgroup of little groups of massless particles and branes is shown to be (and coincide with, at d=4) a subgroup of little groups of "pure branes" algebras, i.e. tensorial Poincare algebras without vector generators. Possible existence of corresponding field theories is discussed. At 11d it is shown that, contrary to lower dimensions, spinors are not homogeneous space...
Branes constrictions with White Dwarfs
Energy Technology Data Exchange (ETDEWEB)
García-Aspeitia, Miguel A., E-mail: aspeitia@fisica.uaz.edu.mx [Consejo Nacional de Ciencia y Tecnología, Av, Insurgentes Sur 1582, Colonia Crédito Constructor, Del. Benito Juárez, C.P. 03940, Mexico, D.F. (Mexico); Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad esquina con Paseo a la Bufa S/N, C.P. 98060, Zacatecas (Mexico)
2015-11-06
We consider here a robust study of stellar dynamics for white dwarf stars with polytropic matter in the weak-field approximation using the Lane–Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze stability and compactness, in order to show whether it is possible to agree with the conventional wisdom of white dwarfs dynamics. Our results predict an average value of the brane tension of <λ>≳84.818 MeV{sup 4}, with a standard deviation σ≃82.021 MeV{sup 4}, which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining higher than cosmological results provided by nucleosynthesis among others.
Branes constrictions with White Dwarfs
Energy Technology Data Exchange (ETDEWEB)
Garcia-Aspeitia, Miguel A. [Consejo Nacional de Ciencia y Tecnologia, Mexico (Mexico); Unidad Academica de Fisica, Universidad Autonoma de Zacatecas (Mexico)
2015-11-15
We consider here a robust study of stellar dynamics for white dwarf stars with polytropic matter in the weak-field approximation using the Lane-Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze stability and compactness, in order to show whether it is possible to agree with the conventional wisdom of white dwarfs dynamics. Our results predict an average value of the brane tension of left angle λ right angle >or similar 84.818 MeV{sup 4}, with a standard deviation σ ≅ 82.021 MeV{sup 4}, which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining higher than cosmological results provided by nucleosynthesis among others. (orig.)
Baldness/delocalization in intersecting brane systems
Peet, A W
2000-01-01
Marginally bound systems of two types of branes are considered, such as the prototypical case of Dp+4 branes and Dp branes. As the transverse separation between the two types of branes goes to zero, different behaviour occurs in the supergravity solutions depending on p; no-hair theorems result for p<=1 only. Within the framework of the AdS/CFT correspondence, these supergravity no-hair results are understood as dual manifestations of the Coleman-Mermin-Wagner theorem. Furthermore, the rates of delocalization for p<=1 are matched in a scaling analysis. Talk given at ``Strings '99''; based on hep-th/9903213 with D. Marolf.
Noncommutative Geometry and D-Branes
Ho, P M; Ho, Pei-Ming; Wu, Yong-Shi
1996-01-01
We apply noncommutative geometry to a system of N parallel D-branes, which is interpreted as a quantum space. The Dirac operator defining the quantum differential calculus is identified to be the supercharge for strings connecting D-branes. As a result of the calculus, Connes' Yang-Mills action functional on the quantum space reproduces the dimensionally reduced U(N) super Yang-Mills action as the low energy effective action for D-brane dynamics. Several features that may look ad hoc in a noncommutative geometric construction are shown to have very natural physical or geometric origin in the D-brane picture in superstring theory.
Remarks on string/five-brane duality
International Nuclear Information System (INIS)
We examine the hypothesis that the heterotic string is dual to the heterotic five-brane, from the point of view of low-energy ten-dimensional supergravity theories. We conclude that (a) the five-brane tension is quantized in units of 2π2α'/κ2 and (b) the five-brane loop coupling constant is given by the inverse cube root of the string loop coupling constant. This latter result supports the idea that the strongly coupled heterotic string is described by the weakly coupled heterotic five-brane, and vice versa. (orig.)
Marginal fluctuations as instantons on M2/D2-branes
Naghdi, M.
2014-03-01
We introduce some (anti-) M/D-branes through turning on the corresponding field strengths of the 11- and 10-dimensional supergravity theories over spaces, where we use and for the internal spaces. Indeed, when we add M2/D2-branes on the same directions with the near horizon branes of the Aharony-Bergman-Jafferis-Maldacena model, all symmetries and supersymmetries are preserved trivially. In this case, we obtain a localized object just in the horizon. This normalizable bulk massless scalar mode is a singlet of and , and it agrees with a marginal boundary operator of the conformal dimension of . However, after performing a special conformal transformation, we see that the solution is localized in the Euclideanized space and is attributable to the included anti-M2/D2-branes, which are also necessary to ensure that there is no back-reaction. The resultant theory now breaks all supersymmetries to , while the other symmetries are so preserved. The dual boundary operator is then set up from the skew-whiffing of the representations and for the supercharges and scalars, respectively, while the fermions remain fixed in of the original theory. Besides, we also address another alternate bulk to boundary matching procedure through turning on one of the gauge fields of the full gauge group along the same lines with a similar situation to the one faced in the AdS/CFT correspondence. The latter approach covers the difficulty already faced with in the bulk-boundary matching procedure for as well.
Brane Localization and Stabilization via the Casimir Effect
Jacobs, David M; Tolley, Andrew J
2012-01-01
Extra-dimensional scenarios have become widespread among particle and gravitational theories of physics to address several outstanding problems, including the dark energy or weak hierarchy problems. In general, the topology and geometry of the full spacetime manifold will be non-trivial, even if our ordinary dimensions have the topology of their covering space. Most compact manifolds are inhomogeneous, even if they admit a homogeneous geometry, and it will be physically relevant where in the extra-dimensions one is located. In this letter, we explore the use of the Casimir effect in a braneworld scenario as a dynamical mechanism to determine and stabilize the location of a single brane. This is possible because the zero point energy in bulk quantum fields that satisfy particular brane boundary conditions depends on the brane location. Thus, there is a position-dependent force on the brane. Here we consider the 2-dimensional horn as a toy model of the extra dimensions and calculate the Casimir energy for a bul...
Branes wrapped on coassociative cycles
International Nuclear Information System (INIS)
We obtain a supergravity solution arising when D6-branes are wrapped on coassociative four-cycles of constant curvature in seven manifolds of G2 holonomy. The solutions preserve two supercharges and thus represent supergravity duals of three dimensional Yang-Mills with N=1 supersymmetry. When uplifted to eleven dimensions our solution describes M-theory on the background of an eight manifold with Spin(7) holonomy. (author)
Dirichlet branes and nonperturbative aspects of supersymmetric string and gauge theories
Energy Technology Data Exchange (ETDEWEB)
Yin, Zheng
1999-05-01
In chapter 1 the author reviews some elements of string theory relevant to the rest of this report. He touches on both the classical, i.e. perturbative, string physics before D-branes rise to prominence, and some of the progresses they brought forth. In chapter 2 he proceeds to give an exact algebraic formulation of D-branes in curved spaces. This allows one to classify them in backgrounds of interest and study their geometric properties. He applies this formalism to string theory on Calabi-Yau and other supersymmetry preserving manifolds. Then he studies the behavior of the D-branes under mirror symmetry in chapter 3. Mirror symmetry is known to be a symmetry of string theory perturbatively. He finds evidence for its nonperturbative validity when D-branes are also considered and compute some dynamical consequences. In chapter 4 he turns to examine the consistency of curved and/or intersecting D-brane configurations. They have been used recently to extract information about the field theories that arise in certain limits. It turns out that there are potential quantum mechanical inconsistencies associated with them. What saves the day are certain subtle topological properties of D-branes. This resolution has implications for the conserved charges carried by the D-branes, which he computes for the cases studied in chapter 2. In chapter 5 he uses intersecting brane configurations to study three dimensional supersymmetric gauge theories. There is also a mirror symmetry there that, among other things, exchanges classical and quantum mechanical quantities of a (mirror) pair of theories. It has an elegant realization in term of a symmetry of string theory involving D-branes. The author employs it to study a wide class of 3d models. He also predicts new mirror pairs and unconventional 3d field theories without Lagrangian descriptions.
Vacuum polarization on the brane
Breen, Cormac; Ottewill, Adrian C; Winstanley, Elizabeth
2015-01-01
We compute the renormalized expectation value of the square of a massless, conformally coupled, quantum scalar field on the brane of a higher-dimensional black hole. Working in the AADD brane-world scenario, the extra dimensions are flat and we assume that the compactification radius is large compared with the size of the black hole. The four-dimensional on-brane metric corresponds to a slice through a higher-dimensional Schwarzschild-Tangherlini black hole geometry and depends on the number of bulk space-time dimensions. The quantum scalar field is in a thermal state at the Hawking temperature. An exact, closed-form expression is derived for the renormalized expectation value of the square of the quantum scalar field on the event horizon of the black hole. Outside the event horizon, this renormalized expectation value is computed numerically. The answer depends on the number of bulk space-time dimensions, with a magnitude which increases rapidly as the number of bulk space-time dimensions increases.
Vacuum polarization on the brane
Breen, Cormac; Hewitt, Matthew; Winstanley, Elizabeth; Ottewill, Adrian C.
2015-10-01
We compute the renormalized expectation value of the square of a massless, conformally coupled, quantum scalar field on the brane of a higher-dimensional black hole. Working in the AADD brane-world scenario, the extra dimensions are flat and we assume that the compactification radius is large compared with the size of the black hole. The four-dimensional on-brane metric corresponds to a slice through a higher-dimensional Schwarzschild-Tangherlini black hole geometry and depends on the number of bulk space-time dimensions. The quantum scalar field is in a thermal state at the Hawking temperature. An exact, closed-form expression is derived for the renormalized expectation value of the square of the quantum scalar field on the event horizon of the black hole. Outside the event horizon, this renormalized expectation value is computed numerically. The answer depends on the number of bulk space-time dimensions, with a magnitude which increases rapidly as the number of bulk space-time dimensions increases.
Hebecker, Arthur; Witkowski, Lukas T
2014-01-01
We analyze string-theoretic large-field inflation in the regime of spontaneously-broken supergravity with conventional moduli stabilization by fluxes and non-perturbative effects. The main ingredient is a shift-symmetric Kahler potential, supplemented by flux-induced shift symmetry breaking in the superpotential. The central technical observation is that all these features are present for D7-brane position moduli in Type IIB orientifolds. On the one hand, in the large complex structure regime they inherit a shift symmetry from their mirror-dual Type IIA Wilson lines. On the other hand, the Type IIB flux superpotential generically breaks this shift symmetry and allows, by appealing to the large flux discretuum, to tune the relevant coefficients to be small. The shift-symmetric direction in D7-brane moduli space can then play the role of the inflaton: While the D7-brane circles a certain trajectory on the Calabi-Yau many times, the corresponding F-term energy density grows only very slowly, thanks to the above-...
Teleparallel loop quantum cosmology in a system of intersecting branes
Sepehri, Alireza; Pradhan, Anirudh; Beesham, Aroonkumar; de Haro, Jaume
2016-09-01
Recently, some authors have removed the big bang singularity in teleparallel Loop Quantum Cosmology (LQC) and have shown that the universe may undergo a number of oscillations. We investigate the origin of this type of teleparallel theory in a system of intersecting branes in M-theory in which the angle between them changes with time. This system is constructed by two intersecting anti-D8-branes, one compacted D4-brane and a D3-brane. These branes are built by joining M0-branes which develop in decaying fundamental strings. The compacted D4-brane is located between two intersecting anti-D8 branes and glues to one of them. Our universe is located on the D3 brane which wraps around the D4 brane from one end and sticks to one of the anti-D8 branes from the other one. In this system, there are three types of fields, corresponding to compacted D4 branes, intersecting branes and D3-branes. These fields interact with each other and make the angle between branes oscillate. By decreasing this angle, the intersecting anti-D8 branes approach each other, the D4 brane rolls, the D3 brane wraps around the D4 brane, and the universe contracts. By separating the intersecting branes and increasing the angle, the D4 brane rolls in the opposite direction, the D3 brane separates from it and the expansion branch begins. Also, the interaction between branes in this system gives us the exact form of the relevant Lagrangian for teleparallel LQC.
Teleparallel loop quantum cosmology in a system of intersecting branes
Directory of Open Access Journals (Sweden)
Alireza Sepehri
2016-09-01
Full Text Available Recently, some authors have removed the big bang singularity in teleparallel Loop Quantum Cosmology (LQC and have shown that the universe may undergo a number of oscillations. We investigate the origin of this type of teleparallel theory in a system of intersecting branes in M-theory in which the angle between them changes with time. This system is constructed by two intersecting anti-D8-branes, one compacted D4-brane and a D3-brane. These branes are built by joining M0-branes which develop in decaying fundamental strings. The compacted D4-brane is located between two intersecting anti-D8 branes and glues to one of them. Our universe is located on the D3 brane which wraps around the D4 brane from one end and sticks to one of the anti-D8 branes from the other one. In this system, there are three types of fields, corresponding to compacted D4 branes, intersecting branes and D3-branes. These fields interact with each other and make the angle between branes oscillate. By decreasing this angle, the intersecting anti-D8 branes approach each other, the D4 brane rolls, the D3 brane wraps around the D4 brane, and the universe contracts. By separating the intersecting branes and increasing the angle, the D4 brane rolls in the opposite direction, the D3 brane separates from it and the expansion branch begins. Also, the interaction between branes in this system gives us the exact form of the relevant Lagrangian for teleparallel LQC.
Radion and moduli stabilization from induced brane actions in higher-dimensional brane worlds
Charmousis, C.; U. Ellwanger
2004-01-01
We consider a 4+N-dimensional brane world with 2 co-dimension 1 branes in an empty bulk. The two branes have N-1 of their extra dimensions compactified on a sphere S^(N-1), whereas the ordinary 4 spacetime directions are Poincare invariant. An essential input are induced stress-energy tensors on the branes providing different tensions for the spherical and flat part of the branes. The junction conditions - notably through their extra dimensional components - fix both the distance between the ...
Brane Cosmology and Higher Derivative Theory
Naboulsi, R
2003-01-01
In this paper, we have considered a cosmological model with density perturbation and decreasing cosmological constant of the form Lambda = 3beta (frac{dot{R}^2}{R^2}) + delta (frac{ddot{R}}{R}), beta, gamma = const. Inspired from brane cosmology, we supposed the presence of exotic density related to the cosmological constant by the formula 2Lambda = 3m^2, where m is a constant having the dimension of Hubble constant. Their effects on the evolution of the spatially, flat FRW cosmoligical model of the Universe is analyzed in the framework of higher derivative theory. The Universe is found to be accelerating with time with no initial singularity for beta < frac{1}{3} and the cosmological constant is found to decrease as t^{-2} but smaller than 3H^2. The presence of interacting scalar field is also discussed.
Brane world in a topological black holes in asymptotically flat spacetime
International Nuclear Information System (INIS)
We study static brane configurations in the bulk background of the topological black holes in asymptotically flat spacetime. We find that such configurations are possible even for flat black hole horizon, unlike the AdS black hole case. We construct the brane world model with an orbifold structure S1/Z2 in such bulk background. We also study massless bulk scalar field. (author)
Cosmological solutions for a two-branes system in a vacuum bulk
Perez, Juan L; Urena-Lopez, L Arturo
2013-01-01
We study the cosmology for a two branes model in a space-time of five dimensions where the extra coordinate is compactified on an orbifold. The hidden brane is filled with a real scalar field endowed with a quadratic potential that behaves as primordial dark matter field. This case is analyzed when the radion effects are negligible in comparison with the density energy; all possible solutions are found by means of a dynamical system approach.
On-brane data for braneworld stars
Visser, M; Visser, Matt; Wiltshire, David L.
2003-01-01
Stellar structure in braneworlds is rather different from that in ordinary general relativity. We completely solve the ``on brane'' 4-dimensional Gauss--Codazzi equations for an arbitrary static spherically symmetric star in a Randall-Sundrum type II braneworld. We then indicate how this on-brane boundary data can be propagated into the bulk to determine the 5-dimensional spacetime geometry.
D-brane recoil and logarithmic operators
Kogan, I I; Wheater, John F; Kogan, Ian I; Mavromatos, Nick E; Wheater, John F
1996-01-01
We construct the pair of logarithmic operators associated with the recoil of a D-brane. This construction establishes a connection between a translation in time and a world-sheet rescaling. The problem of measuring the centre of mass coordinate of the D-brane is considered and the relation between the string uncertainty principle and the logarithmic operators is discussed.
Universal hydrodynamics of non-conformal branes
I. Kanitscheider; K. Skenderis
2009-01-01
We examine the hydrodynamic limit of non-conformal branes using the recently developed precise holographic dictionary. We first streamline the discussion of holography for backgrounds that asymptote locally to non-conformal brane solutions by showing that all such solutions can be obtained from high
Covariant Quantization of D-branes
Kallosh, Renata
1997-01-01
We have found that kappa-symmetry allows a covariant quantization provided the ground state of the theory is strictly massive. For D-p-branes a Hamiltonian analysis is performed to explain the existence of a manifestly supersymmetric and Lorentz covariant description of the BPS states of the theory. The covariant quantization of the D-0-brane is presented as an example.
The Goldstino Brane, the Constrained Superfields and Matter in N=1 Supergravity
Bandos, Igor; Kuzenko, Sergei M; Martucci, Luca; Sorokin, Dmitri
2016-01-01
We show that different (brane and constrained superfield) descriptions for the Volkov-Akulov goldstino coupled to N=1, D=4 supergravity with matter produce similar wide classes of models with spontaneously broken local supersymmetry and discuss the relation between the different formulations. As with the formulations with irreducible constrained superfields, the geometric goldstino brane approach has the advantage of being manifestly off-shell supersymmetric without the need to introduce auxiliary fields. It provides an explicit solution of the nilpotent superfield constraints and avoids issues with non-Gaussian integration of auxiliary fields. We describe general couplings of the supersymmetry breaking sector, including the goldstino and other non-supersymmetric matter, to supergravity and matter supermultiplets. Among various examples, we discuss a goldstino brane contribution to the gravitino mass term and the supersymmetrization of the anti-D3-brane contribution to the effective theory of type IIB warped ...
Black hole, string ball, and p-brane production at hadronic supercolliders
International Nuclear Information System (INIS)
In models of large extra dimensions, the string and Planck scales become accessible at future colliders. When the energy scale is above the string scale or Planck scale a number of interesting phenomena occur, namely, production of stringy states, p-branes, string balls, black hole, etc. In this work, we systematically study the production cross sections of black holes, string balls, and p-branes at hadronic supercolliders. We also discuss their signatures. At the energy scale between the string scale Ms and Ms/gs2, where gs is the string coupling, the production is dominated by string balls, while beyond Ms/gs2 it is dominated by black holes. The production of a p-brane is only comparable to black holes when the p-brane wraps entirely on small extra dimensions. Rough estimates on the sensitivity reaches on the fundamental Planck scale MD are also obtained, based on the number of raw events
Multidimensional Cosmological and Spherically Symmetric Solutions with Intersecting p-branes
Ivashchuk, V D
1999-01-01
Multidimensional model describing the cosmological evolution and/or spherically symmetric configuration with n+1 Einstein spaces in the theory with several scalar fields and forms is considered. When electro-magnetic composite p-brane ansatz is adopted, n "internal" spaces are Ricci-flat, one space M_0 has a non-zero curvature, and all p-branes do not "live" in M_0, a class of exact solutions is obtained if certain block-orthogonality relations on p-brane vectors are imposed. A subclass of spherically-symmetric solutions containing non-extremal p-brane black holes is considered. Post-Newtonian parameters are calculated and some examples are considered.
Null geodesics in brane world universe
International Nuclear Information System (INIS)
We study null bulk geodesic motion in the brane world cosmology in the RS2 scenario and in the static universe in the bulk of the charged topological AdS black hole. We obtain equations describing the null bulk geodesic motion as observed in one lower dimensions. We find that the null geodesic motion in the bulk of the brane world cosmology in the RS2 scenario is observed to be under the additional influence of extra non-gravitational force by the observer on the three-brane, if the brane universe does not possess the Z2 symmetry. As for the null geodesic motion in the static universe in the bulk of the charged AdS black hole, the extra force is realized even when the brane universe has the Z2 symmetry. (author)
Brane induced gravity: Ghosts and naturalness
Eglseer, Ludwig; Schneider, Robert
2015-01-01
Linear stability of brane induced gravity in two codimensions on a static pure tension background is investigated. By explicitly calculating the vacuum persistence amplitude of the corresponding quantum theory, we show that the parameter space is divided into two regions - one corresponding to a stable Minkowski vacuum on the brane and one being plagued by ghost instabilities. This analytical result affirms a recent nonlinear, but mainly numerical analysis. The main result is that the ghost is absent for a sufficiently large brane tension, in perfect agreement with a value expected from a natural effective field theory point of view. Unfortunately, the linearly stable parameter regime is either ruled out phenomenologically or destabilized due to nonlinearities. We argue that inflating brane backgrounds constitute the remaining window of opportunity. In the special case of a tensionless brane, we find that the ghost exists for any nonzero value of the induced gravity scale. Regarding this case, there are contr...
Holographic Cosmic Quintessence on Dilatonic Brane World
Chen, B; Chen, Bin; Lin, Feng-Li
2002-01-01
Recently quintessence is proposed to explain the observation data of supernova indicating a time-varying cosmological constant and accelerating universe. Inspired by this and its mysterious origin, we look for the possibility of quintessence as the holographic dark matters dominated in the late time in the brane world scenarios. We consider both the cases of static and moving brane in a dilaton gravity background. For the static brane we use the Hamilton-Jacobi method to study the intrinsic FRW cosmology on the brane and find out the constraint on the bulk potential for the quintessence. We find the similar constraint for the moving brane cases and that the quintessence on it has the effect as a mildly time-varying Newton constant.
Dimensional Reduction for D3-brane Moduli
Cownden, Brad; Marsh, M C David; Underwood, Bret
2016-01-01
Warped string compactifications are central to many attempts to stabilize moduli and connect string theory with cosmology and particle phenomenology. We present a first-principles derivation of the low-energy 4D effective theory from dimensional reduction of a D3-brane in a warped Calabi-Yau compactification of type IIB string theory with imaginary self-dual 3-form flux, including effects of D3-brane motion beyond the probe approximation, and find the metric on the moduli space of brane positions, the universal volume modulus, and axions descending from the 4-form potential. As D3-branes may be considered as carrying either electric or magnetic charges for the self-dual 5-form field strength, we present calculations in both duality frames. Our results are consistent with, but extend significantly, earlier results on the low-energy effective theory arising from D3-branes in string compactifications.
D-brane Inspired Fermion Mass Textures
Leontaris, G K
2010-01-01
In this paper, the issues of the quark mass hierarchies and the Cabbibo Kobayashi Maskawa mixing are analyzed in a class of intersecting D-brane configurations with Standard Model gauge symmetry. The relevant mass matrices are constructed taking into account the constraints imposed by extra abelian symmetries and anomaly cancelation conditions. Possible mass generating mechanisms including perturbative as well as non-perturbative effects are discussed and specific patterns of mass textures are found characterized by the hierarchies of the scales where the various sources contribute. It is argued that the Cholesky decomposition of the mass matrices is the most appropriate way to determine the properties of these fermion mass patterns, while the associated triangular mass matrix form provides a unified description of all phenomenologically equivalent symmetric and non-symmetric mass matrices. An elegant analytic formula is derived for the Cholesky triangular form of the mass matrices where the entries are given...
Where does curvaton live? -- Distinguishing bulk/brane frames
Larrouturou, François; Namba, Ryo; Watanabe, Yota
2016-01-01
D-brane inflationary models propose candidates for an inflaton embedded in the string theory. In these models, two distinct metrics/frames are naturally introduced, brane and bulk metrics/frames, which are connected by a conformal$+$disformal transformation that depends on the inflaton and its derivatives. It has been shown that physical observables, such as curvature perturbations, that are generated by the inflaton are identical in both frames. However, in the case of curvaton scenarios, the results differ depending on the frames to which the curvaton minimally couples. We examine two models, a slow-roll inflation with an inflection point potential and a model of a rapidly rolling inflaton that conformally couples to gravity. In the first model, the difference between the frames in which the curvaton resides is encoded in the spectral index of the curvature perturbations, depicting the nature of the frame transformation. In the second model, the curvaton on the brane induces a spectral index significantly d...
Radiative symmetry breaking on D-branes at non-supersymmetric singularities
Kitazawa, Noriaki
2006-10-01
The possibility of radiative gauge symmetry breaking on D3-branes at non-supersymmetric orbifold singularities is examined. As an example, a simple model of D3-branes at non-supersymmetric C/Z singularity with some D7-branes for the cancellations of RR tadpoles in twisted sectors is analyzed in detail. We find that there are no tachyon modes in twisted sectors, and NS-NS tadpoles in twisted sectors are canceled out, though uncanceled tadpoles and tachyon modes exist in untwisted sectors. This means that this singularity background is a stable solution of string theory at tree level, though some specific compactification of six-dimensional space should be considered for a consistent untwisted sector. On D3-brane three massless "Higgs doublet fields" and three family "up-type quarks" are realized at tree level. Other fermion fields, "down-type quarks" and "leptons", can be realized as massless modes of the open strings stretching between D3-branes and D7-branes. The Higgs doublet fields have Yukawa couplings with up-type quarks, and they also have self-couplings which give a scalar potential without flat directions. Since there is no supersymmetry, the radiative corrections may naturally develop negative Higgs mass squared and "electroweak symmetry breaking". We explicitly calculate the open string one-loop correction to the Higgs mass squared from twisted sectors, and find that the negative value is indeed realized in this specific model.
Emergence and oscillation of cosmic space by joining M1-branes
Sepehri, Alireza; Capozziello, Salvatore; Ali, Ahmed Farag; Pradhan, Anirudh
2016-01-01
Recently, it has been proposed by Padmanabhan that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region leads to the expansion of the universe. Now, a natural question arises, how this model could explain the oscillation of universe between contraction and expansion branches? We try to address this issue in the framework of BIonic system. In this model, $M0$-branes join to each other and give rise to a pair of $M1$-anti-$M1$-branes. The fields which live on these branes play the roles of massive gravitons that cause the emergence of a wormhole between them and formation of a BIon system. This wormhole dissolves into M1-branes and causes a divergence between the number of degrees of freedom on the boundary surface of $M1$ and the bulk leading to an expansion of $M1$-branes. When $M1$-branes become close to each other, the square energy of their system becomes negative and some tachyonic states emerge. To removes these states, $M1$...
Topics on Strings, Branes and Calabi-Yau Compactifications
García-Compéan, H; Garcia-Compean, Hugo; Loaiza-Brito, Oscar
2000-01-01
Basics of some topics on perturbative and non-perturbative string theory are reviewed. After a mathematical survey of the Standard Model of particle physics and GUTs, the bosonic string kinematics for the free case and with interaction is described. The effective action of the bosonic string and the spectrum is also discussed. Five perturbative superstring theories and their spectra is briefly outlined. Calabi-Yau three-fold compactifications of heterotic strings and their relation to some four-dimensional physics are given. T-duality in closed and open strings are surveyed. D-brane definition is provided and some of their properties and applications to brane boxes configurations, in particular to the cube model are discussed. Finally, non-perturbative issues like S-duality, M-theory, F-theory and basics of their non-perturbative Calabi-Yau compactifications are considered.
Abundance of Asymmetric Dark Matter in Brane World Cosmology
Abdusattar, Haximjan; Iminniyaz, Hoernisa
2016-09-01
Relic abundance of asymmetric Dark Matter particles in brane world cosmological scenario is investigated in this article. Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles. We analyze how the relic abundance of asymmetric Dark Matter is changed in this model. We show that in such kind of nonstandard cosmological scenario, indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti-particle abundance kept in the same amount with the particle. We show the indirect detection signal constraints can be used to such model only when the cross section and the 5-dimensional Planck mass scale are in appropriate values. Supported by the National Natural Science Foundation of China under Grant No. 11365022
Phenomenological analysis of D-brane Pati-Salam vacua
Anastasopoulos, P.; Leontaris, G. K.; Vlachos, N. D.
2010-05-01
In the present work, we perform a phenomenological analysis of the effective low energy models with Pati-Salam (PS) gauge symmetry derived in the context of D-branes. The main issue in these models arises from the fact that the right-handed fermions and the PS-symmetry breaking Higgs field transform identically under the symmetry, causing unnatural matter-Higgs mixing effects. We argue that this problem can be solved in particular D-brane setups where these fields arise in different intersections. We further observe that whenever a large Higgs mass term is being generated in a particular class of mass spectra, a splitting mechanism -reminiscent of the doublet triplet splitting- may protect the neutral Higgs components from becoming heavy. We analyze the implications of each individual representation available in these models in order to specify the minimal spectrum required to build up a consistent model that reconciles the low energy data. A short discussion is devoted to the effects of stringy instanton corrections, particularly those generating missing Yukawa couplings and contributing to the fermion mass textures. We discuss the correlations of the intersecting D-brane spectra with those obtained from Gepner constructions and analyze the superpotential, the resulting mass textures and the low energy implications of some examples of the latter along the lines proposed above.
Radiative Symmetry Breaking on D-branes at Non-supersymmetric Singularities
Kitazawa, N
2006-01-01
The possibility of radiative gauge symmetry breaking on D3-branes at non-supersymmetric orbifold singularities is examined. As an example, a simple model of D3-branes at non-supersymmetric C^3/Z_6 singularity with some D7-branes for the cancellations of R-R tadpoles in twisted sectors is analyzed in detail. We find that there are no tachyon modes in twisted sectors, and NS-NS tadpoles in twisted sectors are canceled out, though uncanceled tadpoles and tachyon modes exist in untwisted sectors. This means that this singularity background is a stable solution of string theory at tree level, though some specific compactification of six-dimensional space should be considered for a consistent untwisted sector. On D3-brane three massless "Higgs doublet fields" and three family "up-type quarks" are realized at tree level. Other fermion fields, "down-type quarks" and "leptons", can be realized as massless modes of the open strings stretching between D3-branes and D7-branes. The Higgs doublet fields have Yukawa couplin...
Codimension-2 Brane Black Holes
Zamorano, Nelson; Arias, Cesar; Ordenes, Ariel; Guzman, Francisco
2012-03-01
We analyze the geometry associated to a six dimensional solution of the Einstein's equations. It describes a Schwarzschild de-Sitter black hole on a 3-brane, surrounded by a two dimensional compact bulk. A four dimensional effective cosmological constant and a Planck mass are matched to their six dimensional counterpart. Deviation from Newton's law are computed in both of the solutions found. To learn about the geometry of the bulk, we study the geodesics in this sector. At least, in our opinion, there are some features of these solutions that makes worth to pursue this analysis. The singularity associated to the warped bulk is controlled by the mass M of the black hole. It vanishes if we set M=0. In the same context, it makes an interesting problem to study the Gregory-Laflamme instability in this context [1]. Another feature is the rugby ball type of geometry exhibited by these solutions [2]. They end up in two conical singularities at its respective poles. The branes are located precisely at the poles. Besides, a Wick's rotation generates a connection between different solutions. [4pt] [1] R. Gregory and R. Laflamme, Phys. Rev Lett., 70,2837 (1993)[0pt] [2] S. M. Carroll and M. M. Guica, arXiv:hep-th/0302067
Accelerating universe in $f({\\cal R})$ brane gravity
Atazadeh, K.; Farhoudi, M.; Sepangi, H. R.
2008-01-01
We study a 5-dimensional $f({\\cal R})$ brane gravity within the framework of scalar-tensor type theories. We show that such a model predicts, for a certain choice of $f({\\cal R})$ and a spatially flat universe, an exponential potential, leading to an accelerated expanding universe driven solely by the curvature of the bulk space. This result is consistent with the observational data in the cosmological scale.
Dvali-Gabadadze-Porrati Cosmology in Bianchi I brane
Ansari, Rizwan Ul Haq
2008-01-01
The dynamics of Dvali-Gabadadze-Porrati Cosmology (DGP) braneworld with an anisotropic brane is studied. The Friedmann equations and their solutions are obtained for two branches of anisotropic DGP model. The late time behavior in DGP cosmology is examined in the presence of anisotropy which shows that universe enters a self-accelerating phase much later compared to the isotropic case. The acceleration conditions and slow-roll conditions for inflation are obtained.
Teleparallel loop quantum cosmology in a system of intersecting branes
Sepehri, Alireza; Beesham, A; de Haro, Jaume
2016-01-01
Recently, some authors have removed the big bang singularity in teleparallel Loop Quantum Cosmology (LQC) and have shown that the universe may undergo a number of oscillations. We investigate the origin of this type of teleparallel theory in a system of intersecting branes in M-theory in which the angle between them changes with time. This system is constructed by two intersecting anti-D8-branes, one compacted D4-brane and the other a D3-brane. These branes are built by joining M0-branes which develop in decaying fundamental strings. The compacted D4-brane is located between two intersecting anti-D8 branes and glues to one of them. Our universe is located on the D3 brane which wraps the D4 brane from one end and sticks to one of the anti-D8 branes from another one. In this system, there are three types of ?elds, corresponding to compacted D4 branes, intersecting branes and D3-branes. These ?elds interact with each other and make the angle between branes oscillate. By decreasing this angle and approaching the ...
E3-brane instantons and baryonic operators for D3-branes on toric singularities
Forcella, Davide; García-Etxebarria, Iñaki; Uranga, Angel
2009-03-01
We consider the couplings induced on the world-volume field theory of D3-branes at local toric Calabi-Yau singularities by euclidean D3-brane (E3-brane) instantons wrapped on (non-compact) holomorphic 4-cycles. These instantons produce insertions of BPS baryonic or mesonic operators of the four-dimensional Script N = 1 quiver gauge theory. We argue that these systems underlie, via the near-horizon limit, the familiar AdS/CFT map between BPS operators and D3-branes wrapped on supersymmetric 3-cycles on the 5d horizon. The relation implies that there must exist E3-brane instantons with appropriate fermion mode spectrum and couplings, such that their non-perturbative effects on the D3-branes induce operators forming a generating set for all BPS operators of the quiver CFT. We provide a constructive argument for this correspondence, thus supporting the picture.
Quantum billiards with branes on product of Einstein spaces
Energy Technology Data Exchange (ETDEWEB)
Ivashchuk, V.D. [VNIIMS, Center for Gravitation and Fundamental Metrology, Moscow (Russian Federation); Peoples' Friendship University of Russia, Institute of Gravitation and Cosmology, Moscow (Russian Federation)
2016-05-15
We consider a gravitational model in dimension D with several forms, l scalar fields and a Λ-term. We study cosmological-type block-diagonal metrics defined on a product of an 1-dimensional interval and n oriented Einstein spaces. As an electromagnetic composite brane ansatz is adopted and certain restrictions on the branes are imposed the conformally covariant Wheeler-DeWitt (WDW) equation for the model is studied. Under certain restrictions, asymptotic solutions to the WDW equation are found in the limit of the formation of the billiard walls. These solutions reduce the problem to the so-called quantum billiard in (n + l -1)-dimensional hyperbolic space. Several examples of quantum billiards in the model with electric and magnetic branes, e.g. corresponding to hyperbolic Kac-Moody algebras, are considered. In the case n = 2 we find a set of basis asymptotic solutions to the WDW equation and derive asymptotic solutions for the metric in the classical case. (orig.)
Electromagnetic perturbations in new brane world scenarios
Molina, C; Torrejon, T E M
2016-01-01
In this work we consider electromagnetic dynamics in Randall-Sundrum branes. It is derived a family of four-dimensional spacetimes compatible with Randall-Sundrum brane worlds, focusing on asymptotic flat backgrounds. Maximal extensions of the solutions are constructed and their causal structures are discussed. These spacetimes include singular, non-singular and extreme black holes. Maxwell's electromagnetic field is introduced and its evolution is studied in an extensive numerical survey. Electromagnetic quasinormal mode spectra are derived and analyzed with time-dependent and high order WKB methods. Our results indicate that the black holes in the brane are electromagnetically stable.
Electromagnetic perturbations in new brane world scenarios
Molina, C.; Pavan, A. B.; Medina Torrejón, T. E.
2016-06-01
In this work, we consider electromagnetic dynamics in Randall-Sundrum branes. It is derived from a family of four-dimensional spacetimes compatible with Randall-Sundrum brane worlds, focusing on asymptotic flat backgrounds. Maximal extensions of the solutions are constructed, and their causal structures are discussed. These spacetimes include singular, nonsingular, and extreme black holes. Maxwell's electromagnetic field is introduced, and its evolution is studied in an extensive numerical survey. Electromagnetic quasinormal mode spectra are derived and analyzed with time-dependent and high-order WKB methods. Our results indicate that the black holes in the brane are electromagnetically stable.
Denouement of a Wormhole-Brane Encounter
Rodrigo, Enrico
2009-01-01
Higher-dimensional black holes have long been considered within the context of brane worlds. Recently, it was shown that the brane-world ethos also permits the consideration of higher-dimensional wormholes. When such a wormhole, preexisting in the bulk, impinges upon our universe, taken to be a positive-tension 3-brane, it can induce the creation in our universe of a wormhole of ordinary dimensionality. The throat of this wormhole might fully constrict, pinch off, and thus birth a baby univer...
A Holographic Bound for D3-Brane
Momeni, Davood; Bahamonde, Sebastian; Myrzakul, Aizhan; Myrzakulov, Ratbay
2016-01-01
In this paper, we will calculate the holographic entanglement entropy, holographic complexity, and fidelity susceptibility for a D3-brane. It will be demonstrated that for a D3-brane the holographic complexity is always greater than or equal to than the fidelity susceptibility. Furthermore, we will also demonstrate that the holographic complexity is related to the holographic entanglement entropy for this system. Thus, we will obtain a holographic bound involving holographic complexity, holographic entanglement entropy and fidelity susceptibility of a D3-brane.
New class of effective field theories from embedded branes.
Goon, Garrett L; Hinterbichler, Kurt; Trodden, Mark
2011-06-10
We present a new general class of four-dimensional effective field theories with interesting global symmetry groups. These theories arise from purely gravitational actions for (3+1)-dimensional branes embedded in higher dimensional spaces with induced gravity terms. The simplest example is the well known Galileon theory, with its associated Galilean symmetry, arising as the limit of a DGP brane world. However, we demonstrate that this is a special case of a much wider range of theories, with varying structures, but with the same attractive features such as second order equations. In some circumstances, these new effective field theories allow potentials for the scalar fields on curved space, with small masses protected by nonlinear symmetries. Such models may prove relevant to the cosmology of both the early and late universe. PMID:21770494
Brane Effective Actions, Kappa-Symmetry and Applications
Simon, Joan
2011-01-01
This is a review on brane effective actions, their symmetries and some of its applications. Its first part uncovers the Green-Schwarz formulation of single M- and D-brane effective actions focusing on kinematical aspects : the identification of their degrees of freedom, the importance of world volume diffeomorphisms and kappa symmetry, to achieve manifest spacetime covariance and supersymmetry, and the explicit construction of such actions in arbitrary on-shell supergravity backgrounds. Its second part deals with applications. First, the use of kappa symmetry to determine supersymmetric world volume solitons. This includes their explicit construction in flat and curved backgrounds, their interpretation as BPS states carrying (topological) charges in the supersymmetry algebra and the connection between supersymmetry and hamiltonian BPS bounds. When available, I emphasise the use of these solitons as constituents in microscopic models of black holes. Second, the use of probe approximations to infer about non-tr...
Reheating the D-brane universe via instant preheating
International Nuclear Information System (INIS)
We investigate a possibility of reheating in a scenario of D-brane inflation in a warped deformed conifold background which includes perturbative corrections to throat geometry sourced by a chiral operator of dimension 3/2 in the conformal field theory. The effective D-brane potential, in this case, belongs to the class of nonoscillatory models of inflation for which the conventional reheating mechanism does not work. We find that gravitational particle production is inefficient and leads to reheating temperature of the order of 108 GeV. We show that instant preheating is quite suitable to the present scenario and can easily reheat the universe to a temperature which is higher by about 3 orders of magnitude than its counterpart associated with gravitational particle production. The reheating temperature is shown to be insensitive to a particular choice of inflationary parameters suitable to observations.
Brane-world cosmological perturbations a covariant approach
Maartens, R
2002-01-01
The standard cosmological model, based on general relativity with an inflationary era, is very effective in accounting for a broad range of observed features of the universe. However, the ongoing puzzles about the nature of dark matter and dark energy, together with the problem of a fundamental theoretical framework for inflation, indicate that cosmology may be probing the limits of validity of general relativity. The early universe provides a testing ground for theories of gravity, since gravitational dynamics can lead to characteristic imprints on the CMB and other cosmological observations. Precision cosmology is in principle a means to constrain and possibly falsify candidate quantum gravity theories like M theory. Generalized Randall-Sundrum brane-worlds provide a phenomenological means to test aspects of M theory. I outline the 1+3-covariant approach to cosmological perturbations in these brane-worlds, and its application to CMB anisotropies.
Classical tests of General Relativity in thick branes
Dahia, F
2014-01-01
Classical tests of General Relativity in braneworld scenarios have been investigated recently with the purpose of posing observational constraints on parameters of some models of infinitely thin brane. Here we consider the motion of test particles in a thick brane scenario that corresponds to a regularized version of the Garriga-Tanaka solution, which describes a black hole solution in RSII model, in the weak field regime. By adapting a mechanism previously formulated in order to describe the confinement of massive tests particles in a domain wall (that simulates classically the trapping of the Dirac field in a domain wall), we study the influence of the brane thickness on the four-dimensional (4D) path of massless particles. Although the geometry is not warped and, therefore, the bound motion in the transverse direction is not decoupled from the movement in the 4D-world, we can find an explicit solution for the light deflection and the time delay, if the motion in the fifth direction is a high frequency osci...
Sepehri, Alireza; Capozziello, Salvatore; Ali, Ahmed Farag; Pradhan, Anirudh
2016-01-01
Recently, it has been suggested in [JHEP 12(2015)003] that the Brown-York mechanism can be used to measure the quasilocal energy in Lovelock gravity. We have used this method in a system of M0-branes and show that the Brown-York energy evolves in the process of birth and growth of Lovelock gravity. This can help us to predict phenomenological events which are emerged as due to dynamical structure of Lovelock gravity in our universe. In this model, first, M0-branes join to each other and form an M3-brane and an anti-M3-branes connected by an M2-brane. This system is named BIon. Universes and anti-universes live on M3-branes and M2 plays the role of wormhole between them. By passing time, M2 dissolves in M3's and nonlinear massive gravities like Lovelock massive gravity emerges and grows. By closing M3-branes, BIon evolves and wormhole between branes makes a transition to black hole. During this stage, Brown-York energy increases and shrinks to large values at the colliding points of branes. By approaching M3-b...
Brane Creation in M(atrix) Theory
Ho, P M; Ho, Pei-Ming; Wu, Yong-Shi
1998-01-01
We discuss, in the context of M(atrix) theory, the creation of a membrane suspended between two longitudinal five-branes when they cross each other. It is shown that the membrane creation originates from the degrees of freedom in the off-diagonal blocks which are related via dualities to the chiral fermionic zero mode on a 0-8 string. In the dual system of a D0-brane and a D8-brane in type IIA theory the half-integral charges associated with the "half"-strings are found to be connected to the well-known fermion-number fractionalization in the presence of a fermionic zero mode. At sufficiently short distances, the effective potential between the two five-branes is dominated by the zero mode contribution to the vacuum energy.
Cosmological perturbations on the phantom brane
Bag, Satadru; Viznyuk, Alexander; Shtanov, Yuri; Sahni, Varun
2016-07-01
We obtain a closed system of equations for scalar perturbations in a multi-component braneworld. Our braneworld possesses a phantom-like equation of state at late times, weff Consequently, the quasi-static approximation of Koyama and Maartens provides a good fit to the exact results during the matter-dominated epoch. We find that the late-time growth of density perturbations on the brane proceeds at a faster rate than in ΛCDM. Additionally, the gravitational potentials Φ and Ψ evolve differently on the brane than in ΛCDM, for which Φ = Ψ. On the brane, by contrast, the ratio Φ/Ψ exceeds unity during the late matter-dominated epoch (z lesssim 50). These features emerge as smoking gun tests of phantom brane cosmology and allow predictions of this scenario to be tested against observations of galaxy clustering and large-scale structure.
Holography of Dyonic Dilaton Black Branes
Goldstein, Kevin; Kachru, Shamit; Prakash, Shiroman; Trivedi, Sandip P; Westphal, Alexander
2010-01-01
We study black branes carrying both electric and magnetic charges in Einstein-Maxwell theory coupled to a dilaton-axion in asymptotically anti de Sitter space. After reviewing and extending earlier results for the case of electrically charged branes, we characterise the thermodynamics of magnetically charged branes. We then focus on dyonic branes in theories which enjoy an $SL(2,R)$ electric-magnetic duality. Using $SL(2,R)$, we are able to generate solutions with arbitrary charges starting with the electrically charged solution, and also calculate transport coefficients. These solutions all exhibit a Lifshitz-like near-horizon geometry. The system behaves as expected for a charged fluid in a magnetic field, with non-vanishing Hall conductance and vanishing DC longitudinal conductivity at low temperatures. Its response is characterised by a cyclotron resonance at a frequency proportional to the magnetic field, for small magnetic fields. Interestingly, the DC Hall conductance is related to the attractor value ...
Holographic thermalization from nonrelativistic branes
Roychowdhury, Dibakar
2016-05-01
In this paper, based on the fundamental principles of gauge/gravity duality and considering a global quench, we probe the physics of thermalization for certain special classes of strongly coupled nonrelativistic quantum field theories that are dual to an asymptotically Schrödinger D p brane space time. In our analysis, we note that during the prelocal stages of the thermal equilibrium the entanglement entropy has a faster growth in time compared to its relativistic cousin. However, it shows a linear growth during the postlocal stages of thermal equilibrium where the so-called tsunami velocity associated with the linear growth of the entanglement entropy saturates to that of its value corresponding to the relativistic scenario. Finally, we explore the saturation region and it turns out that one must constraint certain parameters of the theory in a specific way in order to have discontinuous transitions at the point of saturation.
Lectures on branes in curved backgrounds
International Nuclear Information System (INIS)
These lectures provide an introduction to the microscopic description of branes in curved backgrounds. After a brief reminder of the flat space theory, the basic principles and techniques of (rational) boundary conformal field theory are presented in the second lecture. The general formalism is then illustrated through a detailed discussion of branes on compact group manifolds. In the final lecture, many more recent developments are reviewed, including some results for non-compact target spaces
Soft branes in supersymmetry-breaking backgrounds
McGuirk, Paul; Shiu, Gary; Ye, Fang
2012-01-01
We revisit the analysis of effective field theories resulting from non-supersymmetric perturbations to supersymmetric flux compactifications of the type-IIB superstring with an eye towards those resulting from the backreaction of a small number of anti-D3-branes. Independently of the background, we show that the low-energy Lagrangian describing the fluctuations of a stack of probe D3-branes exhibits soft supersymmetry breaking, despite perturbations to marginal operators that were not fully c...
Brane Space-Time and Cosmology
Naboulsi, R
2003-01-01
I reconsider the cosmology of a 3-brane universe imbedded in a five-dimensional anti-de Sitter space AdS5 with a cosmological constant and show that the resulting Friedmann equations for this system are identical to those standard obtained in 4D FRW space-time in the presence of an additional density, playing two roles: the tension of the brane and the gravitino density We discuss some important concequences on hot big bang cosmology.
Thick Brane Split Caused by Spacetime Torsion
Yang, Jie; Li, Yun-Liang; Zhong, Yuan; Li, Yang
2012-01-01
In this paper we apply the five-dimensional $f(T)$ gravity with $f(T)=T+k T^n$ to brane scenario to explore the solutions under a given warp factor, and we find that the analytic domain wall solution will be a double-kink solution when the geometric effect of spacetime torsion is strongly enhanced. We also investigate the localization of fermion fields on the split branes corresponding to the double-kink solution.
Brane inflation without slow-roll
Matsuda, T
2007-01-01
The scenario of brane inflation without using the conventional slow-roll approximations has been investigated. Based on the mechanism of generating the curvature perturbations at the end of inflation, a new brane inflation paradigm was developed. The conditions for making a sufficiently large enough number of e-foldings and for generating the curvature perturbations without producing dangerous relics were also examined. Benefits of our scenario are subsequently discussed in detail.
Brane inflation without slow-roll
Matsuda, Tomohiro
2007-03-01
The scenario of brane inflation without using the conventional slow-roll approximations has been investigated. Based on the mechanism of generating the curvature perturbations at the end of inflation, a new brane inflation paradigm was developed. The conditions for making a sufficiently large enough number of e-foldings and for generating the curvature perturbations without producing dangerous relics were also examined. Benefits of our scenario are subsequently discussed in detail.
Non-Abelian BIonic Brane Intersections
Cook, P; Murugan, J; Cook, Paul; Koch, Robert de Mello; Murugan, Jeff
2003-01-01
We study "fuzzy funnel" solutions to the non-Abelian equations of motion of the D-string. Our funnel describes n^6/360 coincident D-strings ending on n^3/6 D7-branes, in terms of a fuzzy six-sphere which expands along the string. We also provide a dual description of this configuration in terms of the world volume theory of the D7-branes.
Marginal fluctuations as instantons on M2/D2-branes
Energy Technology Data Exchange (ETDEWEB)
Naghdi, M. [University of Ilam, Department of Physics, Faculty of Basic Sciences, Ilam (Iran, Islamic Republic of)
2014-03-15
We introduce some (anti-) M/D-branes through turning on the corresponding field strengths of the 11- and 10-dimensional supergravity theories over AdS{sub 4} x M{sup 7} {sup vertical} {sup stroke} {sup 6} spaces, where we use S{sup 7}/Z{sub k} and CP{sup 3} for the internal spaces. Indeed, when we add M2/D2-branes on the same directions with the near horizon branes of the Aharony-Bergman-Jafferis- Maldacena model, all symmetries and supersymmetries are preserved trivially. In this case, we obtain a localized object just in the horizon. This normalizable bulk massless scalar mode is a singlet of SO(8) and SU(4) x U(1), and it agrees with a marginal boundary operator of the conformal dimension of Δ{sub +} = 3. However, after performing a special conformal transformation, we see that the solution is localized in the Euclideanized AdS{sub 4} space and is attributable to the included anti-M2/D2-branes, which are also necessary to ensure that there is no back-reaction. The resultant theory now breaks all N = 8, 6 supersymmetries to N = 0, while the other symmetries are so preserved. The dual boundary operator is then set up from the skew-whiffing of the representations 8s and 8v for the supercharges and scalars, respectively, while the fermions remain fixed in 8c of the original theory. Besides, we also address another alternate bulk to boundary matching procedure through turning on one of the gauge fields of the full U(N){sub k} x U(N){sub -k} gauge group along the same lines with a similar situation to the one faced in the AdS{sub 5}/CFT{sub 4} correspondence. The latter approach covers the difficulty already faced with in the bulk-boundary matching procedure for k = 1, 2 as well. (orig.)
Holographic backgrounds from D-brane probes
Moskovic, Micha
2014-01-01
This thesis focuses on the derivation of holographic backgrounds from the field theory side, without using any supergravity equations of motion. Instead, we rely on the addition of probe D-branes to the stack of D-branes generating the background. From the field theory description of the probe branes, one can compute an effective action for the probes (in a suitable low-energy/near-horizon limit) by integrating out the background branes. Comparing this action with the generic probe D-brane action then allows to determine the holographic background dual to the considered field theory vacuum. In the first part, the required pre-requisites of field and string theory are recalled and this strategy to derive holographic backgrounds is explained in more detail on the basic case of D3-branes in flat space probed by a small number of D-instantons. The second part contains our original results, which have already appeared in arXiv:1301.3738, arXiv:1301.7062 and arXiv:1312.0621. We first derive the duals to three conti...
On D-brane moduli stabilisation
Marchesano, Fernando; Zoccarato, Gianluca
2014-01-01
Standard results in 4d N=1 string compactifications assign a number of moduli to each space-time filling D-brane, computed by analysing the D-brane action in a fixed background. We revisit such conventional wisdom and argue that this naive counting of open string moduli is incorrect, in the sense that some of them will be lifted when making dynamical the bulk degrees of freedom. We explicitly discuss this effect for D6-branes wrapping special Lagrangian three-cycles, showing that some geometric and Wilson line moduli are lifted even before taking into account worldsheet instanton effects. From a 4d effective theory viewpoint the moduli lifting is due to an F-term potential, and can be deduced from the superpotentials in the literature. From a microscopic viewpoint the lifting is due to D-brane backreaction effects and flux quantisation in a compact manifold, and provides a mechanism for lifting Wilson line moduli. The latter applies to certain D6-branes and D7-brane Wilson lines, yielding new possibilities to...
Brane inflation and the WMAP data: a Bayesian analysis
Lorenz, Larissa; Ringeval, Christophe
2007-01-01
The Wilkinson Microwave Anisotropy Probe (WMAP) constraints on string inspired ``brane inflation'' are investigated. Here, the inflaton field is interpreted as the distance between two branes placed in a flux-enriched background geometry and has a Dirac-Born-Infeld (DBI) kinetic term. Our method relies on an exact numerical integration of the inflationary power spectra coupled to a Markov-Chain Monte-Carlo exploration of the parameter space. This analysis is valid for any perturbative value of the string coupling constant and of the string length, and includes a phenomenological modelling of the reheating era to describe the post-inflationary evolution. It is found that the data favour a scenario where inflation stops by violation of the slow-roll conditions well before brane annihilation, rather than by tachyonic instability. Concerning the background geometry, it is established that log(v) > -10 at 95% confidence level (CL), where "v" is the dimensionless ratio of the five-dimensional sub-manifold at the ba...
Brane-World Black Holes and Energy-Momentum Vector
Salti, M; Korunur, M; Aydogdu, Oktay; Korunur, Murat; Salti, Mustafa
2006-01-01
The Brane-World black hole models are investigated to evaluate their relative energy and momentum components. We consider Einstein and M{\\o}ller's energy-momentum prescriptions in general relativity, and also perform the calculation of energy-momentum density in M{\\o}ller's tetrad theory of gravity. For the Brane-World black holes we show that although Einstein and M{\\o}ller complexes, in general relativity give different energy relations, they yield the same results for the momentum components. In addition, we also make the calculation of the energy-momentum distribution in teleparallel gravity, and calculate exactly the same energy as that obtained by using M{\\o}ller's energy-momentum prescription in general relativity. This interesting result supports the viewpoint of Lessner that the M{\\o}ller energy-momentum complex is a powerful concept for the energy and momentum. We also give five different examples of Brane-World black holes and find the energy distributions associated with them. The result calculate...
Conservation laws for colliding branes with induced gravity
Pellen, Mathieu
2015-05-01
We derive conservation laws for collisions of self-gravitating n-branes (or n-dimensional shells) in an ( n+2) dimensional spacetime including induced gravity on the brane. Previous work has shown how geometrical identities in general relativity enforce conservation of energy-momentum at collisions. The inclusion of induced gravity terms introduces a gravitational self-energy on the brane which permits energy-momentum conservation of matter fields on the brane to be broken, so long as the total energy-momentum, including induced gravity terms, is conserved. We give simple examples with two branes (one ingoing and one outgoing) and three branes.
Conservation laws for colliding branes with induced gravity
Pellen, Mathieu
2013-01-01
We derive conservation laws for collisions of self-gravitating $n$-branes (or $n$-dimensional shells) in an $(n+2)$ dimensional spacetime including induced gravity on the brane. Previous work has shown how geometrical identities in general relativity enforce conservation of energy-momentum at collisions. The inclusion of induced gravity terms introduces a gravitational self-energy on the brane which permits energy-momentum conservation of matter fields on the brane to be broken, so long as the total energy-momentum, including induced gravity terms, is conserved. We give simple examples with two branes (one ingoing and one outgoing) and three branes.
There and back again: A T-brane's tale
Bena, Iosif; Minasian, Ruben; Savelli, Raffaele
2016-01-01
T-branes are supersymmetric configurations described by multiple Dp-branes with worldvolume flux and non-commuting vacuum expectation values for two of the worldvolume scalars. When these values are much larger than the string scale this description breaks down. We show that in this regime the correct description of T-branes is in terms of a single Dp-brane, whose worldvolume curvature encodes the T-brane data. We present the tale of the journey to reach this picture, which takes us through T-dualities and rugby-ball-shaped brane configurations that no eye has gazed upon before.
On the localization of four-dimensional brane-world black holes
International Nuclear Information System (INIS)
In the context of brane-world models, we pursue the question of the existence of five-dimensional solutions describing regular black holes localized close to the brane. Employing a perturbed Vaidya-type line-element embedded in a warped fifth dimension, we attempt to localize the extended black-string singularity, and to restore the regularity of the AdS spacetime at a finite distance from the brane by introducing an appropriate bulk energy–momentum tensor. As a source for this bulk matter, we are considering a variety of non-ordinary field-theory models of scalar fields either minimally coupled to gravity, but including non-canonical kinetic terms, mixing terms, derivative interactions and ghosts, or non-minimally coupled to gravity through a general coupling to the Ricci scalar. In all models considered, even in those characterized by a high degree of flexibility, a negative result was reached. Our analysis demonstrates how difficult the analytic construction of a localized brane-world black hole may be in the context of a well-defined field-theory model. Finally, with regard to the question of the existence or not of a static classical black-hole solution on the brane, our analysis suggests that such solutions could in principle exist; however, the associated field configuration itself has to be dynamic. (paper)
Grand unification in the heterotic brane world
Energy Technology Data Exchange (ETDEWEB)
Vaudrevange, Patrick Karl Simon
2008-08-15
String theory is known to be one of the most promising candidates for a uni ed description of all elementary particles and their interactions. Starting from the ten-dimensional heterotic string, we study its compactification on six-dimensional orbifolds. We clarify some important technical aspects of their construction and introduce new parameters, called generalized discrete torsion. We identify intrinsic new relations between orbifolds with and without (generalized) discrete torsion. Furthermore, we perform a systematic search for MSSM-like models in the context of Z{sub 6}-II orbifolds. Using local GUTs, which naturally appear in the heterotic brane world, we construct about 200 MSSM candidates. We find that intermediate SUSY breaking through hidden sector gaugino condensation is preferred in this set of models. A specific model, the so-called benchmark model, is analyzed in detail addressing questions like the identification of a supersymmetric vacuum with a naturally small {mu}-term and proton decay. Furthermore, as vevs of twisted fields correspond to a resolution of orbifold singularities, we analyze the resolution of Z{sub 3} singularities in the local and in the compact case. Finally, we exemplify this procedure with the resolution of a Z{sub 3} MSSM candidate. (orig.)
Grand unification in the heterotic brane world
International Nuclear Information System (INIS)
String theory is known to be one of the most promising candidates for a uni ed description of all elementary particles and their interactions. Starting from the ten-dimensional heterotic string, we study its compactification on six-dimensional orbifolds. We clarify some important technical aspects of their construction and introduce new parameters, called generalized discrete torsion. We identify intrinsic new relations between orbifolds with and without (generalized) discrete torsion. Furthermore, we perform a systematic search for MSSM-like models in the context of Z6-II orbifolds. Using local GUTs, which naturally appear in the heterotic brane world, we construct about 200 MSSM candidates. We find that intermediate SUSY breaking through hidden sector gaugino condensation is preferred in this set of models. A specific model, the so-called benchmark model, is analyzed in detail addressing questions like the identification of a supersymmetric vacuum with a naturally small μ-term and proton decay. Furthermore, as vevs of twisted fields correspond to a resolution of orbifold singularities, we analyze the resolution of Z3 singularities in the local and in the compact case. Finally, we exemplify this procedure with the resolution of a Z3 MSSM candidate. (orig.)
Simulation of a bounded symport/antiport P system with Brane calculi.
Vitale, Antonio; Mauri, Giancarlo; Zandron, Claudio
2008-03-01
Membrane systems (also called P systems) and Brane calculi have been recently introduced as formal models inspired by the structure and the functioning of living cells, but having in mind different goals. The aim of Membrane systems was the formal investigation of the computational nature and power of various features of the cell, while Brane calculi aims to define a model capable of a faithful and intuitive representation of various biological processes. The common background of the two formalisms and the recent growing of interests in applying P systems in Systems Biology have raised the natural question of bridging this two research areas. The present paper goes in this direction, as it presents a direct simulation of a variant of P systems by means of Brane calculi. In particular, we consider a Brane calculus based on three operations called Mate/Bud/Drip, and we show how to use such system to simulate Simple symport/antiport P systems, a variant of P systems purely based on communication of objects. As an example, a simplified sodium-potassium pump modeled in Simple SA is encoded in Mate/Bud/Drip Brane calculus. PMID:17889992
Transport properties of non-conformal gluonic matter from compactified D4 branes
Wu, Chao; Huang, Mei
2015-01-01
We investigate non-conformal transport properties of gluonic matter via the fluid/gravity correspondence from compactified D4 branes. The D4-D6 model and the Sakai-Sugimoto (SS) model are two non-conformal holographic QCD models from top- down, whose background is the compactified D4 black branes under the near horizon limit. By using the dimensional reduction technique, we derive a 5D Einstein gravity minimally coupled with 3 scalar fields from the 10D D4 brane background. Following the boundary derivative expansion formalism of fluid/gravity correspondence, we obtain for the first time all the first order transport coefficients separately for non-conformal gluonic matter, and the ratio of the bulk to shear viscosity and the sound speed are consistent with former studies.
D7-Brane Moduli Space in Axion Monodromy and Fluxbrane Inflation
Arends, Maximilian; Heimpel, Konrad; Kraus, Sebastian C; Lust, Dieter; Mayrhofer, Christoph; Schick, Christoph; Weigand, Timo
2014-01-01
We analyze the quantum-corrected moduli space of D7-brane position moduli with special emphasis on inflationary model building. D7-brane deformation moduli are key players in two recently proposed inflationary scenarios: The first, D7-brane chaotic inflation, is a variant of axion monodromy inflation which allows for an effective 4d supergravity description. The second, fluxbrane inflation, is a stringy version of D-term hybrid inflation. Both proposals rely on the fact that D7-brane coordinates enjoy a shift-symmetric Kahler potential at large complex structure of the Calabi-Yau threefold, making them naturally lighter than other fields. This shift symmetry is inherited from the mirror-dual Type IIA Wilson line on a D6-brane at large volume. The inflaton mass can be provided by a tree-level term in the flux superpotential. It induces a monodromy and, if tuned to a sufficiently small value, can give rise to a large-field model of inflation. Alternatively, by a judicious flux choice one can completely avoid a ...
Brane-world stars from minimal geometric deformation, and black holes
Casadio, Roberto; Ovalle, Jorge
2014-02-01
Using the effective four-dimensional Einstein field equations, we build analytical models of spherically symmetric stars in the brane-world, in which the external space-time contains both an ADM mass and a tidal charge. In order to determine the interior geometry, we apply the principle of minimal geometric deformation, which allows one to map general relativistic solutions to solutions of the effective four-dimensional brane-world equations. We further restrict our analysis to stars with a radius linearly related to the total general relativistic mass, and obtain a general relation between the latter, the brane-world ADM mass and the tidal charge. In these models, the value of the star's radius can then be taken to zero smoothly, thus obtaining brane-world black hole metrics with a tidal charge solely determined by the mass of the source and the brane tension. We find configurations which entail a partial screening of the gravitational mass, and general conclusions regarding the minimum mass for semiclassical black holes are also drawn.
Brane probes, toric geometry, and closed string tachyons
Energy Technology Data Exchange (ETDEWEB)
Sarkar, Tapobrata. E-mail: tapo@ictp.trieste.it
2003-01-13
We study non-supersymmetric orbifold singularities from the point of view of D-brane probes. We present a description of the decay of such singularities from considerations of the toric geometry of the probe branes.
Brane Probes, Toric Geometry, and Closed String Tachyons
Sarkar, Tapobrata
2002-01-01
We study non-supersymmetric orbifold singularities from the point of view of D-brane probes. We present a description of the decay of such singularities from considerations of the toric geometry of the probe branes.
Brane cosmological evolution in a bulk with cosmological constant
Binetruy, Pierre; Deffayet, Cedric; Ellwanger, Ulrich; Langlois, David
1999-01-01
We consider the cosmology of a ``3-brane universe'' in a five dimensional (bulk) space-time with a cosmological constant. We show that Einstein's equations admit a first integral, analogous to the first Friedmann equation, which governs the evolution of the metric in the brane, whatever the time evolution of the metric along the fifth dimension. We thus obtain the cosmological evolution in the brane for any equation of state describing the matter in the brane, without needing the dependence o...
Induced higher-derivative massive gravity on a 2-brane in 4D Minkowski space
International Nuclear Information System (INIS)
In this paper we revisit the problem of localizing gravity in a 2-brane embedded in a 4D Minkowski space to address induction of high derivative massive gravity. We explore the structure of propagators to find well-behaved higher-derivative massive gravity induced on the brane. Exploring a special case in the generalized mass term of the graviton propagator we find a model of consistent higher order gravity with an additional unitary massive spin-2 particle and two massless particles: one spin-0 particle and one spin-1 particle. The condition for the absence of tachyons is satisfied for both ‘right’ and ‘wrong’ signs of the Einstein–Hilbert term on the 2-brane. We also find the Pauli–Fierz mass term added to the new massive gravity in three dimensions and recover the low-dimensional DGP model
Bulk scalar field in brane-worlds with induced gravity inspired by the L(R) term
Energy Technology Data Exchange (ETDEWEB)
Heydari-Fard, M. [Department of Physics, The University of Qom, Qom 37185-359 (Iran, Islamic Republic of); Sepangi, H.R., E-mail: heydarifard@qom.ac.ir, E-mail: hr-sepangi@sbu.ac.ir [Department of Physics, Shahid Beheshti University, Evin, Tehran 19839 (Iran, Islamic Republic of)
2009-01-15
We obtain the effective field equations in a brane-world scenario within the framework of a DGP model where the action on the brane is an arbitrary function of the Ricci scalar, L(R), and the bulk action includes a scalar field in the matter Lagrangian. We obtain the Friedmann equations and acceleration conditions in the presence of the bulk scalar field for the R{sup n} term in four-dimensional gravity.
String Thermodynamics in D-Brane Backgrounds
Abel, S A; Kogan, I I; Rabinovici, Eliezer
1999-01-01
We discuss the thermal properties of string gases propagating in various D-brane backgrounds in the weak-coupling limit, and at temperatures close to the Hagedorn temperature. We determine, in the canonical ensemble, whether the Hagedorn temperature is limiting or non-limiting. This depends on the dimensionality of the D-brane, and the size of the compact dimensions. We find that in many cases the non-limiting behaviour manifest in the canonical ensemble is modified to a limiting behaviour in the microcanonical ensemble and show that, when there are different systems in thermal contact, the energy flows into open strings on the `limiting' D-branes of largest dimensionality. Such energy densities may eventually exceed the D-brane intrinsic tension. We discuss possible implications of this for the survival of Dp-branes with large values of p in an early cosmological Hagedorn regime. We also discuss the general phase diagram of the interacting theory, as implied by the holographic and black-hole/string correspon...
D-brane solitons and boojums in field theory and Bose–Einstein condensates
International Nuclear Information System (INIS)
In certain field theoretical models, composite solitons consisting of a domain wall and vortex lines attached to the wall have been referred to as ‘D-brane solitons’. We show that similar composite solitons can be realized in phase-separated two-component Bose–Einstein condensates. We discuss the similarities and differences between topological solitons in the Abelian–Higgs model and those in two-component Bose–Einstein condensates. On the basis of the formulation of gauge theory, we introduce the ‘boojum charge’ to characterize the D-brane soliton in Bose–Einstein condensates. (paper)
Pure geometric thick f(R)-branes: stability and localization of gravity
Energy Technology Data Exchange (ETDEWEB)
Zhong, Yuan; Liu, Yu-Xiao [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China)
2016-06-15
We study two exactly solvable five-dimensional thick brane world models in pure metric f(R) gravity. Working in the Einstein frame, we show that these solutions are stable against small linear perturbations, including the tensor, vector, and scalar modes. For both models, the corresponding gravitational zero mode is localized on the brane, which leads to the four-dimensional Newton law; while the massive modes are non-localized and only contribute a small correction to the Newton law at a large distance. (orig.)
A 5D Holographic Dark Energy in DGP-Brane Cosmology
Farajollahi, H.; Ravanpak, A.
2016-01-01
This paper is aimed at investigating a 5D holographic dark energy in DGP-BRANE cosmology by employing a combination of Sne Ia, BAO and CMB observational data to fit the cosmological parameters in the model. We describe the dynamic of a FRW for the normal branch ($\\epsilon$ = +1) of solutions of the induced gravity brane-world model. We take the matter in 5D bulk as holographic dark energy that its holographic nature is reproduced effectively in 4D. The cosmic evolution reveals that the effect...
Pure geometric thick f( R)-branes: stability and localization of gravity
Zhong, Yuan; Liu, Yu-Xiao
2016-06-01
We study two exactly solvable five-dimensional thick brane world models in pure metric f( R) gravity. Working in the Einstein frame, we show that these solutions are stable against small linear perturbations, including the tensor, vector, and scalar modes. For both models, the corresponding gravitational zero mode is localized on the brane, which leads to the four-dimensional Newton law; while the massive modes are non-localized and only contribute a small correction to the Newton law at a large distance.
Proposal for non-BPS D-brane action
Kluson, J
2000-01-01
In this short note we would like to propose a form for the action of a non-BPS D-brane, which will be manifestly supersymmetric invariant and T-duality covariant. We also explicitly show that tachyon condensation on the world-volume of this brane leads to the Dirac-Born-Infeld action for BPS D(p-1)-brane.
The many faces of brane-flux annihilation
Gautason, Fridrik Freyr; Van Riet, Thomas
2015-01-01
Fluxes can decay via the nucleation of Brown-Teitelboim bubbles, but when the decaying fluxes induce D-brane charges this process must be accompanied with an annihilation of D-branes. This occurs via dynamics inside the bubble wall as was well described for (anti-)D3 branes branes annihilating against 3-form fluxes. In this paper we extend this to the other Dp branes with p smaller than seven. Generically there are two decay channels: one for the RR flux and one for the NSNS flux. The RR channel is accompanied by brane annihilation that can be understood from the Dp branes polarising into D(p+2) branes, whereas the NSNS channel corresponds to Dp branes polarising into NS5 branes or KK5 branes. We illustrate this with the decay of antibranes probing local toroidal throat geometries obtained from T-duality of the D6 solution in massive type IIA. We show that anti-Dp branes are metastable against annihilation in these backgrounds, at least at the probe level.
Exciting gauge field and gravitons in brane-antibrane annihilation.
Mazumdar, Anupam; Stoica, Horace
2009-03-01
In this Letter we point out the inevitability of an explosive production of gauge field and gravity wave during an open string tachyon condensation in a cosmological setting, in an effective field theory model. We will be particularly studying a toy model of brane-antibrane inflation in a warped throat where inflation ends via tachyon condensation. We point out that a tachyonic instability helps fragmenting the homogeneous tachyon and excites gauge field and contributes to the stress-energy tensor which also feeds into the gravity waves.