In this paper we generalize the construction of locally boosted black brane space time to higher derivative gravities. We consider the Gauss-Bonnet term (with coefficient $α'$) as a toy example. We find the solution to the $α'$ corrected Einstein equations to first order in the boundary derivative expansion. This allows us to find the $α'$ corrections to the boundary stress tensor in the presence of the Gauss-Bonnet term in the bulk action. We therefore obtain the ratio of shear viscosity to entropy which agrees with other methods of computation in the literature.
We study non-perturbative effects due to a heterotic M-theory five-brane wrapped on Calabi-Yau threefold. We show that such instantons contribute to derivative F-terms described recently by Beasley and Witten rather than to the superpotential.
Canonical forms are given for the nilpotent BRS operator $\d$ and the covariant `loop space' derivative ${\cal D}_{\m}$ for the p-brane fields for all odd p. The defining characteristic of ${\cal D}_{\m}$ is that it is a functional derivative operator which generalizes the ordinary functional derivative and also commutes with $\d$. Methods of construction for the canonical forms are discussed.
We find examples in string theory of locally wrapped D-branes. These excitations mimic skyrmions in that they correspond to topological excitations of the scalar fields parametrizing the brane motion in the space transverse to its world-volume. While these brane excitations appear to be point-like, evidence is provided that curvature corrections to the probe action might allow for a delocalization of the wrapping on a scale of the order of the string length, therefore rendering the phenomena non-singular.
By explicit calculation, we show that the expansion of the disk level S-matrix element of one RR field, two open string tachyons and one gauge field that has been recently found corresponds to the derivative expansion of the Wess-Zumino action of D-brane-anti-D-brane systems.
We evaluate the string theory disc amplitude of one Ramond-Ramond field C^(p-3) and two Neveu-Schwarz B-fields in the presence of a single Dp-brane in type II string theory. From this amplitude we extract the four-derivative (or equivalently order (alpha')^2) part of the Dp-brane action involving these fields. We show that the new couplings are invariant under R-R and NS-NS gauge transformations and compatible with linear T-duality.
The Wess-Zumino coupling on D-branes in string theory is known to receive higher derivative corrections which couple the Ramond-Ramond potential to terms involving the square of the spacetime curvature tensor. Consistency with T-duality implies that the branes should also have four-derivative couplings that involve the NS-NS B-field. We use T-duality to predict some of these couplings. We then confirm these results with string worldsheet computations by evaluating disc amplitudes with insertions of one R-R and two NS-NS vertex operators.
We study world-volume effective theories of five-branes in type II string theories. We determine the bosonic zero-modes of the NS5-brane, the Kaluza-Klein monopole, the exotic Q5-, R5-branes and a space-filling brane, by direct calculations within the formalism of double field theory (DFT). We show that these zero-modes are Nambu-Goldstone modes associated with the spontaneously broken gauge symmetries in DFT. They are organized into the bosonic part of the six-dimensional $\mathcal{N} = (1,1)$ vector and the $\mathcal{N} = (2,0)$ tensor multiplets. Among other things, we examine the locally n…
Using the superembedding formalism we construct supermembrane actions with higher derivative terms which can be viewed as possible higher order terms in effective actions. In particular, we provide the first example of an action for an extended supersymmetric object with fully $κ$-symmetric extrinsic curvature terms.
We dimensionally reduce the four-derivative corrections to the parity-conserving part of the D9-brane effective action involving all orders of the gauge field, to obtain corrections to the actions for the lower-dimensional Dp-branes. These corrections involve the second fundamental form and correspond to a non-geodesic embedding of the Dp-brane into (flat) ten-dimensional space. In addition, we study the transformation of the corrections under the Seiberg-Witten map relating the ordinary and non-commutative theories. A speculative discussion about the higher-order terms in the derivative expan…
We show how the superembedding formalism can be applied to construct manifestly kappa-symmetric higher derivative corrections for the D9-brane. We also show that all correction terms appear at even powers of the fundamental length scale $l$. We explicitly construct the first potential correction, which corresponds to the kappa-symmetric version of the $\partial^4 F^4$, which one finds from the four-point amplitude of the open superstring.
We consider the theory of higher derivative gravity with non-factorizable Randall-Sundrum type space-time and obtain the metric solutions which characterize the $p$-brane world-volume as a curved or planar defect embedded in the higher dimensions. We consider the string inspired effective actions of the dilatonic Gauss-Bonnet type in the brane background and show its consistency with the RS brane-world scenario and the conformal weight of the dilaton couplings in the string theory with apppropriate choice of Regge slope ($α'$) or Gauss-Bonnet coupling ($α$) or both. We also discuss a time depe…
We study derivative corrections to the effective action for a single D-brane in type II superstring theory coupled to constant background fields. In particular, within this setting we determine the complete expression for the (disk level) four-derivative corrections to the Born-Infeld part of the action. We also determine 2n-form 2n-derivative corrections to the Wess-Zumino term. Both types of corrections involve all orders of the gauge field strength, F. The results are obtained via string sigma-model loop calculations using the boundary state operator language. The corrections can be succinc…
We compute four-derivative corrections to the AdS supergravity actions arising from the near-horizon geometry of N M5-branes wrapped on either one or two Riemann surfaces. This setup features the novel presence of both gauged isometries as well as nontrivial hypermultiplets. We argue that the 5d Chern-Simons terms receive not only higher-derivative corrections but also contributions from Killing vector parameters, which we find must also be corrected. We check the central charges found by our supergravity methods against the dual field theory results and find perfect agreement at leading and s…
Higher derivative bulk gravity (without Riemann tensor square term) admits AdS-Schwarzschild black hole as exact solution. It is shown that induced brane geometry on such background is open, flat or closed FRW radiation dominated Universe. Higher derivative terms contributions appear in the Hawking temperature, entropy and Hubble parameter via the redefinition of 5-dimensional gravitational constant and AdS scale parameter. These higher derivative terms do not destroy the AdS-dual description of radiation represented by strongly-coupled CFT. Cardy-Verlinde formula which expresses cosmological …
The general model of higher derivative (HD) gravity is considered. The search of brane-world cosmology in such theory is presented when bulk is d5 AdS and boundary is spherical, hyperbolic or flat (single) brane. It is found the wide range of theory parameters where such cosmology may be realized. Special attention is paid to the version of HD theory representing SG dual of ${\cal N}=2$ $Sp(N)$ SCFT (in next-to-leading order of large $N$ expansion). In particular, it is shown that inflationary brane Universe does not occur for SG dual while hyperbolic brane occurs (which was not possible in le…
Using alpha'^3 terms of type IIB supergravity action we study higher order corrections to the non-relativistic non-extremal D3-brane. Utilizing the corrected solution we evaluate corrections to temperature, entropy and shear viscosity. We also compute the eta/s ratio which although within the range of validity of the supergravity approximation and in the lowest order of the correction the universal bound is respected, there is a possibility for a violation of the bound when higher terms in the expansion are taken into account.
We reconstruct the tachyon effective action for unstable D-branes in superstring theory by examining its behaviour near exactly marginal deformations, where the ambigous higher derivative terms can be eliminated. We then compare this action with that obtained in boundary string field theory and find remarkable agreement. In particular, the tension for lower dimensional branes and the BI-action for the centre of mass motion are reprodued exactly. We also comment on the action for tachyons on the kink in a D-brane/anti-D-brane system and on bosonic string theory.
In this letter we address the problem of inducing boundary degrees of freedom from a bulk theory whose action contains higher-derivative corrections. As a model example we consider a topological theory with an action that has only a ``higher-derivative'' term. By choosing specific coupling of the brane to the bulk we show that the boundary action contains gravity action along with some higher-derivative corrections. The co-dimension of the brane is more than one. In this sense the boundary is singular.
We study the fluctuation spectrum of linearized gravity around non-fine-tuned branes. We focus on the case of an AdS4 brane in AdS5. In this case, for small cosmological constant, the warp factor near the brane is essentially that of a Minkowski brane. However, far from the brane, the metric differs substantially. The space includes the AdS5 boundary, so it has infinite volume. Nonetheless, for sufficiently small AdS4 cosmological constant, there is a bound state graviton in the theory, and four-dimensional gravity is reproduced. However, it is a massive bound state that plays the role of the …
We explore the possibility of generalizing the locally localized gravity model in five space-time dimensions to arbitrary higher dimensions. In a space-time with negative cosmological constant, there are essentially two kinds of higher-dimensional cousins which not only take an analytic form but also are free from the naked curvature singularity in a whole bulk space-time. One cousin is a trivial extension of five-dimensional model, while the other one is in essence in higher dimensions. One interesting observation is that in the latter model, only anti-de Sitter ($AdS_p$) brane is physically …
We calculate in detail the disk level S-matrix element of one Ramond-Ramond field and three gauge field vertex operators in the world volume of BPS branes, to find four gauge field couplings to all orders of $α'$ up to on-shell ambiguity. Then using these infinite couplings we find that the massless pole of the field theory amplitude is exactly equal to the massless pole S-matrix element of this amplitude for the $p=n$ case to all orders of $α'$. Finally we show that the infinite massless poles and the contact terms of this amplitude for the $p=n+2$ case can be reproduced by the Born-Infeld ac…
By calculating various disk level S-matrix elements and studying in details their momentum expansions, we have extracted some of the couplings in tachyon DBI action and Wess-Zumino terms of the non-BPS branes, and their higher derivative corrections. In particular, we have found that there is exact consistency between field theory and string theory tachyon pole of S-matrix element of one RR and three tachyons provided that one takes into account the fact that the tachyon vertex operator in 0 picture to be along the Pauli matrix $σ_1$ whereas the tachyon in -1 picture to be along the $σ_2$ dire…
We explored a variety of brane configurations in our previous paper within the two derivative truncation of the unstable D9-brane effective theory. In this paper we extend our previous results with emphasis on the inclusion of the higher derivative corrections for the tachyon and the gauge fields computed in the boundary string field theories. We give the exact solutions to BPS brane configurations studied in our previous paper and find remarkable exact agreements of their energies and RR-charges with the expected results. We further find a few more solutions that we could not construct in the…
We present exact classical solutions of the higher-derivative theory that describes the dynamics of the position modulus of a probe brane within a five-dimensional bulk. The solutions can be interpreted as static or time-dependent throats connecting two parallel branes. In the nonrelativistic limit the brane action is reduced to that of the Galileon theory. We derive exact solutions for the Galileon, which reproduce correctly the shape of the throats at large distances, but fail to do so for their central part. We also determine the parameter range for which the Vainshtein mechanism is reprodu…
We have examined the momentum expansion of the disk level S-matrix element of two tachyons and two gauge fields to find, up to on-shell ambiguity, the couplings of these fields in the world volume theory of N coincident non-BPS D-branes to all order of $α'$. Using the proposal that the action of D-brane-anti-D-brane is given by the projection of the action of two non-BPS D-branes with $(-1)^{F_L}$, we find the corresponding couplings in the world volume theory of the brane-anti-brane system. Using these infinite tower of couplings, we then calculate the massless pole of the scattering amplitud…
General model of multidimensional $R^2$-gravity including Riemann tensor square term (non-zero $c$ case) is considered. The number of brane-worlds in such model is constructed (mainly in five dimensions) and their properties are discussed. Thermodynamics of S-AdS BH (with boundary) is presented when perturbation on $c$ is used. The entropy, free energy and energy are calculated. For non-zero $c$ the entropy (energy) is not proportional to the area (mass). The equation of motion of brane in BH background is presented as FRW equation. Using dual CFT description it is shown that dual field theory…
D2-branes are studied in the context of Born-Infeld theory as a source of the 3-form RR gauge potential. Considering the static case with only a radial magnetic field it is shown that a locally stable hemispherical deformation of the brane exists which minimises the energy locally. Since the D2-brane carries also the charge of D0-branes, and the RR spacetime potential is unbounded from below, these can tunnel to condense on the D2-brane. The corresponding instanton-like configuration and the tunneling rate are derived and discussed.
A Casimir obstruction to asymptotically flat black-brane completions of non-supersymmetric 7-branes
High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；SOKENDAI（综合研究大学院大学）；RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN（理化学研究所交叉理论数学科学中心）
We show that the conformal anomaly for N M5-branes grows like $N^3$. The method we employ relates Coulomb branch interactions in six dimensions to interactions in four dimensions using supersymmetry. This leads to a relation between the six-dimensional conformal anomaly and the conformal anomaly of N=4 Yang-Mills. Along the way, we determine the structure of the four derivative interactions for the toroidally compactified (2,0) theory, while encountering interesting novelties in the structure of the six derivative interactions.
Higher derivative terms are computed in the one-loop effective action governing the interactions of D3-branes, in two ways: (1) in a formalism with N=2 supersymmetry preserved off-shell, and (2) in the standard background field formalism, with only on-shell supersymmetry. It is shown that these calculations only agree using tree-level equations of motion. The off-shell supersymmetric calculation exhibits acceleration terms that appear in terms with four derivatives. These may imply disagreement at two-loop order between supergravity and Yang-Mills descriptions of D-brane dynamics.
We discuss the computation of the leading corrections to D-brane solutions due to higher derivative terms in the corresponding low energy effective action. We develop several alternative methods for analyzing the problem. In particular, we derive an effective one-dimensional action from which the field equations for spherically symmetric two-block brane solutions can be derived, show how to obtain first order equations, and discuss a few other approaches. We integrate the equations for extremal branes and obtain the corrections in terms of integrals of the evaluation of the higher derivative t…
We study higher derivative corrections to black brane thermodynamics and their implications for the weak gravity conjecture for $p$-form gauge fields. In particular we show that higher derivative corrections decrease tension-to-charge ratios of extremal black branes as implied by the weak gravity conjecture, if four-derivative couplings follow scattering positivity bounds. We also demonstrate that entropy corrections in the micro canonical ensemble are positive under the same assumptions. This extends earlier works in the Einstein-Maxwell theory to $p$-form gauge fields in general spacetime di…
We investigate brane world models in higher-derivative gravity theories where the gravitational Lagrangian is an arbitrary function of the Ricci scalar. Making use of the conformal equivalence of such gravity models and Einstein-Hilbert gravity with a scalar field, we deduce the main features of higher-derivative gravity brane worlds. We solve for a gravity model that has corrections quadratic in the Ricci scalar and show one can evade both fine-tuning and the need for a bulk cosmological constant. An analysis of tensor and scalar perturbations shows gravity is localized on the brane and we re…
Extending the analysis of hep-th/0504128, we obtain a formal expression for the coupling between brane matter and the radion in a Randall-Sundrum braneworld. This effective theory is correct to all orders in derivatives of the radion in the limit of small brane separation, and, in particular, contains no higher than second derivatives. In the case of cosmological symmetry the theory can be obtained in closed form and reproduces the five-dimensional behaviour. Perturbations in the tensor and scalar sectors are then studied. When the branes are moving, the effective Newtonian constant on the bra…
In our continued efforts of matching full string computations with the corresponding effective field theory computations, we evaluate string theory correlators in closed forms. In particular, we consider a correlator between three SYM vertex operators and one Ramond-Ramond $C$-field vertex operator: $<V_{C}V_ϕ V_AV_A>$. We show that the infinite number of massless poles of this amplitude can be reproduced by the Born-Infeld action, the Wess-Zumino terms, and their higher derivative corrections. More specifically we find, up to an on-shell ambiguity, two scalar field and two gauge field couplin…
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 `…
We study the interplay between four-derivative 4d gauged supergravity, holography, wrapped M5-branes, and theories of class $\mathcal{R}$. Using results from Chern-Simons theory on hyperbolic three-manifolds and the 3d-3d correspondence we are able to constrain the two independent coefficients in the four-derivative supergravity Lagrangian. This in turn allows us to calculate the subleading terms in the large-$N$ expansion of supersymmetric partition functions for an infinite class of three-dimensional $\mathcal{N}=2$ SCFTs of class $\mathcal{R}$. We also determine the leading correction to th…
We obtain an effective theory for the radion dynamics of the two-brane Randall Sundrum model, correct to all orders in brane velocity in the limit of close separation, which is of interest for studying brane collisions and early Universe cosmology. Obtained via a recursive solution of the Bulk equation of motions, the resulting theory represents a simple extension of the corresponding low-energy effective theory to the high energy regime. The four-dimensional low-energy theory is indeed not valid when corrections at second order in velocity are considered. This extension has the remarkable pro…
We give simple arguments for new non-renormalization theorems on higher derivative couplings of gauge theories to supergravity, with sixteen supersymmetries, by considerations of brane-bulk superamplitudes. This leads to some exact results on the effective coupling of D3-branes in type IIB string theory. We also derive exact results on higher dimensional operators in the torus compactification of the six dimensional (0, 2) superconformal theory.
We study the localization property of antisymmetric tensor fields in the locally localized gravity models. It is shown that all the antisymmetric tensor fields, including the vector field, in a bulk space-time are trapped on an $AdS$ brane by a gravitational interaction where the presence of the brane cosmological constant plays an important role as in the cases of the other bulk fields. The normalized zero-modes spread rather widely in extra space so small extra dimensions might be needed in order not to conflict with experiment.
We propose a non-linear extension of U(1) \times U(1) (abelian) ABJM model including T_{M2} (higher derivative) corrections. The action proposed here is expected to describe a single M2-brane proving C^4/Z_k target space. The model includes couplings with the 3-form background in the eleven-dimensional supergravity which is consistent with the orbifold projection. We show that the novel higgs mechanism proposed by Mukhi and Papageorgakis does work even in the presence of higher derivative corrections and couplings with the background field, giving the correct structure of the Dirac-Born-Infeld…
The near horizon geometry of a fundamental string wrapped around an S1 reduced to four dimensions is expected to be AdS2 x S2. A probe string analysis suggests a no-force condition indicating supersymmetry, which coincides with the condition that the AdS2 is embedded in AdS3. We therefore consider the bulk string theory in terms of a WZW model on AdS3 following recent proposals by Dabholkar et. al and Giveon et. al. We find that conformal symmetry of the model naturally leads to the no-force constraints obtained from the probes. Moreover, we are able to extract the values of the moduli that ac…
In the present and accompanying papers we explicitly construct the on-shell supersymmetric component actions for 3-branes moving in D=6 and in D=8 within the nonlinear realizations framework. In the first paper we apply our schema to construct the action of supersymmetric 3-brane in D=6. It turns out that all ingredients entering the component action can be obtained almost algorithmically by using the nonlinear realizations approach. Within this approach, properly adapted to the construction of on-shell component actions, we pay much attention to broken supersymmetry. Doing so, we were able to…
The tachyon effective field theory describing the dynamics of a non-BPS D-brane in superstring theory has an infinitely thin but finite tension kink solution describing a codimension one BPS D-brane. We study the world-volume theory of massless modes on the kink, and show that the world volume action has precisely the Dirac-Born-Infeld (DBI) form without any higher derivative corrections. We generalize this to a vortex solution in the effective field theory on a brane-antibrane pair. As in the case of the kink, the vortex is infinitely thin, has finite energy density, and the world-volume acti…
Recently, it has been observed that the IIB scattering amplitudes are compatible with the standard rules of S-duality. Inspired by this observation, we will find the tree-level S-matrix elements of one Ramond-Ramond and three open strings by imposing this symmetry on the tree-level S-matrix elements of one Kalb-Ramond and three open strings. We also find a SL(2, R) invariant form of the D3-brane effective action containing four gauge fields with derivative corrections that was derived from one-loop level four-point amplitude. Using the expansion of the nonlinear SL(2, R) invariant structures, …
In this work, we study the higher-derivative massive gravity in $D$-dimensional space-time with the mass term arisen due to a 2-brane embedded in a $4D$ Minkowski spacetime. We consider the effect of a resonance mass term from the DGP braneworld model for the higher-derivative massive gravity. Moreover, we add the gravitational Chern-Simons and Ricci-Cotton terms to this model and evaluate the graviton propagator using a basis of Barnes-Rivers spin projectors. Using the obtained propagator, we proceed with discussing the consistency of the model, writing the dispersion relations, and analyzing…
In this paper, we use only the equation of motion for an interacting system of gravity, dilaton and antisymmetric tensor to study the black brane solutions. By making use of the property of Schwarzian derivative, we obtain the complete solution of this system of equations. For some special values we obtain the well-known BPS brane and black brane solutions.
We extend the recent work on fluid-gravity correspondence to charged black-branes by determining the metric duals to arbitrary charged fluid configuration up to second order in the boundary derivative expansion. We also derive the energy-momentum tensor and the charge current for these configurations up to second order in the boundary derivative expansion. We find a new term in the charge current when there is a bulk Chern-Simons interaction thus resolving an earlier discrepancy between thermodynamics of charged rotating black holes and boundary hydrodynamics. We have also confirmed that all o…
We develop further the effective fluid theory of stationary branes. This formalism applies to stationary blackfolds as well as to other equilibrium brane systems at finite temperature. The effective theory is described by a Lagrangian containing the information about the elastic dynamics of the brane embedding as well as the hydrodynamics of the effective fluid living on the brane. The Lagrangian is corrected order-by-order in a derivative expansion, where we take into account the dipole moment of the brane which encompasses finite-thickness corrections, including transverse spin. We describe …
We consider a class of higher order corrections in the form of Euler densities of arbitrary rank $n$ to the standard gravity action in $D$ dimensions. We have previously shown that this class of corrections allows for domain wall solutions despite the presence of higher powers of the curvature. In the present paper we explicitly solve the linearized equation of motion for gravity fluctuations around the domain wall background and show that there always exist one massless state (graviton) propagating on the wall and a continuous tower of massive states propagating in the bulk.
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 higher dimensional asymptotically locally AdS solutions by suitable dimensional reduction and continuation in the dimension. As a consequence, many holographic results for such backgrounds follow from the corresponding results of the Asymptotically AdS case. In particular, the hydrodynamics of non-confo…
We consider supersymmetric gauge theories coupled to hyper multiplets on five and six dimensional orbifolds and determine the bulk and local fixed point renormalizations of the gauge couplings. We infer from a component analysis that the hyper multiplet does not induce renormalization of the brane gauge couplings on the five dimensional orbifold S^1/Z_2. This is not due to supersymmetry, since the bosonic and fermionic contributions cancel separately. We extend this investigation to T^2/Z_N orbifolds using supergraph techniques in six dimensions. On general Z_N orbifolds the gauge couplings do…
We consider the effect of the R^4 term in type IIA string theory on the supergravity background dual to N_c D4 branes compactified on a circle with supersymmetry breaking boundary conditions. We study the dynamics of D8 branes in this perturbed geometry in the probe approximation. This leads to an analysis of higher derivative corrections in holographic QCD beyond the supergravity approximation. We make a rough estimate of the corrections to the masses of some of the lightest (axial) vector mesons. The corrections are suppressed by a factor of (g_{YM}^2 N_c)^{-3} compared to their supergravity…
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 weak gravity on either brane is indistinguishable from 4-dimensional higher derivative gravity, provided that the inter-brane distance (radion) is stabilized, that the background bulk scalar field is changing near the branes and that the bac…
This thesis is devoted to derivative corrections to the effective action of D-branes, and to mirror symmetry with D-branes. Series of derivative corrections first predicted by non-commutative gauge theory are completed by couplings between the metric and the gauge field. The result is interpreted as a deformation of the non-commutative gauge theory, whose structure survives. The derivation is applied to the tachyon field, whose potential is shown to be deformed by the very same corrections. Moreover, a prescription is given for the coupling of p-adic strings to a magnetic field, thus allowing …
We construct four dimensional intersecting D6-brane models that have locally the spectrum of the N=1 Supersymmetric Standard Model. All open {\em visible} string sectors share the same N=1 supersymmetry. As expected in these supersymmetric classes of models, where the D6-branes wrap a toroidal orientifold of type IIA, the hierarchy may be stabilized if the string scale is low, e.g. below 30 TeV. We analyze the breaking of supersymmetry in the vicinity of the supersymmetric point by turning on complex structure deformations as Fayet-Iliopoulos terms. Positive masses for all squarks and sleptons…
In order to localize fermions on branes with codimension one, one usually introduces the Yukawa coupling between fermions and background scalar fields or the recently proposed derivative fermion-scalar coupling in [Phys. Rev. D 89 (2014) 086001]. In this paper, we explore the coupling between a spinor field $Ψ$ and the scalar curvature of spacetime $R$, $ηΨΓ^M\partial_M F(R)γ^5\barΨ$ with $F(R)$ a function of $R$, to investigate localization of the fermion. Because of $Z_2$ symmetry of the extra dimension, the new coupling mechanism proposed here can easily deal with the problem encountered in…
We investigate the black hole solutions in the $R^2$-gravity, where the action contains the square of the curvature. In case that the action does not contain the square of the Riemann tensor and in case that the $R^2$-terms are the Gauss-Bonnet (GB) combination, we find exact solutions. We investigate the thermodynamics of these theories and find the Hawking-Page like phase transition, which is the phase transition between the black hole (BH) spacetime and the pure anti-deSitter (AdS) spacetime. From the viewpoint of the AdS/CFT correspondence, such a phase transition may correspond to thermal…
