Hamiltonian analysis of BHT massive gravity
Blagojević, M
2010-01-01
We study the Hamiltonian structure of the Bergshoeff-Hohm-Townsend (BHT) massive gravity with a cosmological constant. In the space of coupling constants $(\\Lambda_0,m^2)$, our canonical analysis reveals the special role of the condition $\\Lambda_0/m^2\
Hamiltonian analysis of BHT massive gravity
Blagojević, M.; Cvetković, B.
2011-01-01
We study the Hamiltonian structure of the Bergshoeff-Hohm-Townsend (BHT) massive gravity with a cosmological constant. In the space of coupling constants ( Λ 0, m 2), our canonical analysis reveals the special role of the condition Λ 0/ m 2 ≠ -1. In this sector, the dimension of the physical phase space is found to be N ∗ = 4, which corresponds to two Lagrangian degree of freedom. When applied to the AdS asymptotic region, the canonical approach yields the conserved charges of the BTZ black hole, and central charges of the asymptotic symmetry algebra.
Black-hole dynamics in BHT massive gravity
Maeda, Hideki
2011-02-01
Using an exact Vaidya-type null-dust solution, we study the area and entropy laws for dynamical black holes defined by a future outer trapping horizon in (2 + 1) dimensional Bergshoeff-Hohm-Townsend (BHT) massive gravity. We consider the theory admitting a degenerate (anti-)de Sitter vacuum and pure BHT gravity. It is shown that, while the area of a black hole decreases by the injection of a null dust with positive energy density in several cases, the Wald-Kodama dynamical entropy always increases.
Canonical structure of BHT massive gravity in warped AdS{sub 3} sector
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Mahdavian Yekta, Davood, E-mail: d.mahdavian@hsu.ac.ir
2016-08-10
We investigate the asymptotic structure of the three dimensional Warped Anti-de Sitter (WAdS{sub 3}) black holes in the Bergshoeff–Hohm–Townsend (BHT) massive gravity using the canonical Hamiltonian formalism. We define the canonical asymptotic gauge generators, which produce the conserved charges and the asymptotic symmetry group for the WAdS{sub 3} black holes. The attained symmetry group is described by a semi-direct sum of a Virasoro and a Kač–Moody algebra. Using the Sugawara construction, we obtain a direct sum of two Virasoro algebras. We show that not only the asymptotic conserved charges satisfy the first law of black hole thermodynamics, but also they lead to the expected Smarr formula for the WAdS{sub 3} black holes. We also show that the black hole's entropy obeys the Cardy formula of the dual conformal field theory (CFT).
Canonical structure of BHT massive gravity in warped AdS3 sector
Mahdavian Yekta, Davood
2016-08-01
We investigate the asymptotic structure of the three dimensional Warped Anti-de Sitter (WAdS3) black holes in the Bergshoeff-Hohm-Townsend (BHT) massive gravity using the canonical Hamiltonian formalism. We define the canonical asymptotic gauge generators, which produce the conserved charges and the asymptotic symmetry group for the WAdS3 black holes. The attained symmetry group is described by a semi-direct sum of a Virasoro and a Kač-Moody algebra. Using the Sugawara construction, we obtain a direct sum of two Virasoro algebras. We show that not only the asymptotic conserved charges satisfy the first law of black hole thermodynamics, but also they lead to the expected Smarr formula for the WAdS3 black holes. We also show that the black hole's entropy obeys the Cardy formula of the dual conformal field theory (CFT).
Canonical structure of BHT massive gravity in warped AdS3 sector
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Davood Mahdavian Yekta
2016-08-01
Full Text Available We investigate the asymptotic structure of the three dimensional Warped Anti-de Sitter (WAdS3 black holes in the Bergshoeff–Hohm–Townsend (BHT massive gravity using the canonical Hamiltonian formalism. We define the canonical asymptotic gauge generators, which produce the conserved charges and the asymptotic symmetry group for the WAdS3 black holes. The attained symmetry group is described by a semi-direct sum of a Virasoro and a Kač–Moody algebra. Using the Sugawara construction, we obtain a direct sum of two Virasoro algebras. We show that not only the asymptotic conserved charges satisfy the first law of black hole thermodynamics, but also they lead to the expected Smarr formula for the WAdS3 black holes. We also show that the black hole's entropy obeys the Cardy formula of the dual conformal field theory (CFT.
Gravitational solitons, hairy black holes and phase transitions in BHT massive gravity
Pérez, Alfredo; Tempo, David; Troncoso, Ricardo
2011-07-01
Hairy black holes and gravitational solitons in three dimensions for the new (BHT) massive gravity theory are considered at the special case when there is a unique maximally symmetric solution. Following the Brown-York approach with suitable counterterms, it is shown that the soliton possesses a fixed negative mass which coincides with that of AdS spacetime regardless the value of the integration constant that describes it. The soliton is then regarded as a degenerate ground state labeled by a modulus parameter. The Euclidean action is shown to be finite and independent of modulus and hair parameters for both classes of solutions, reproducing the hairy black hole free energy. Modular invariance implies that the gravitational hair becomes determined by the modulus parameter. Cardy formula is shown to agree with the semiclassical entropy provided the modulus parameter of the ground state is spontaneously fixed, suggesting that the hairy black hole is in a broken phase. Indeed, it is found that the critical temperature T c = (2 πl)-1 characterizes a first order phase transition between the static hairy black hole and the soliton which, due to the existence of gravitational hair, can take place in the semiclassical regime.
Three-dimensional black holes, gravitational solitons, kinks and wormholes for BHT massive gravity
Oliva, Julio; Tempo, David; Troncoso, Ricardo
2009-07-01
The theory of massive gravity in three dimensions recently proposed by Bergshoeff, Hohm and Townsend (BHT) is considered. At the special case when the theory admits a unique maximally symmetric solution, a conformally flat solution that contains black holes and gravitational solitons for any value of the cosmological constant is found. For negative cosmological constant, the black hole is characterized in terms of the mass and the ``gravitational hair'' parameter, providing a lower bound for the mass. For negative mass parameter, the black hole acquires an inner horizon, and the entropy vanishes at the extremal case. Gravitational solitons and kinks, being regular everywhere, can be obtained from a double Wick rotation of the black hole. A wormhole solution in vacuum that interpolates between two static universes of negative spatial curvature is obtained as a limiting case of the gravitational soliton with a suitable identification. The black hole and the gravitational soliton fit within a set of relaxed asymptotically AdS conditions as compared with the one of Brown and Henneaux. In the case of positive cosmological constant the black hole possesses an event and a cosmological horizon, whose mass is bounded from above. Remarkably, the temperatures of the event and the cosmological horizons coincide, and at the extremal case one obtains the analogue of the Nariai solution, dS2 × S1. A gravitational soliton is also obtained through a double Wick rotation of the black hole. The Euclidean continuation of these solutions describes instantons with vanishing Euclidean action. For vanishing cosmological constant the black hole and the gravitational soliton are asymptotically locally flat spacetimes. The rotating solutions can be obtained by boosting the previous ones in the t-phi plane.
Canonical structure of BHT massive gravity in warped AdS3 sector
Yekta, Davood Mahdavian
2016-01-01
We investigate the asymptotic structure of the three dimensional warped anti de sitter black holes in the Bergshoeff, Hohm and Townsend massive gravity using the canonical Hamiltonian formalism. We define the canonical asymptotic guage generators, which produce the conserved charges and the asymptotic symmetry group for the warped anti de sitter black holes. The attained symmetry group is described by a semi direct sum of a Virasoro and a KacMoody algebra. Using the Sugawara construction, we obtain a direct sum of two Virasoro algebras. We show that not only the asymptotic conserved charges satisfy the first law of black hole thermodynamics, but also they lead to the expected Smarr formula for the warped anti de sitter black holes. We also show that the black hole entropy obeys the Cardy formula of the dual conformal field theory .
National Research Council Canada - National Science Library
de Rham, Claudia
2014-01-01
We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP...
Claudia de Rham
2016-01-01
We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...
de Rham, Claudia
2014-01-01
We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...
2014-01-01
We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware–Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...
Extra gauge symmetries in BHT gravity
Blagojević, M
2011-01-01
We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by $\\Lambda_0/m^2=-1$, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.
Extra gauge symmetries in BHT gravity
Blagojević, M.; Cvetković, B.
2011-03-01
We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by Λ 0/ m 2 = -1, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.
Quantum massive conformal gravity
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Faria, F.F. [Universidade Estadual do Piaui, Centro de Ciencias da Natureza, Teresina, PI (Brazil)
2016-04-15
We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed. (orig.)
Deser, S; Ong, Y C; Waldron, A
2014-01-01
The method of characteristics is a key tool for studying consistency of equations of motion; it allows issues such as predictability, maximal propagation speed, superluminality, unitarity and acausality to be addressed without requiring explicit solutions. We review this method and its application to massive gravity theories to show the limitations of these models' physical viability: Among their problems are loss of unique evolution, superluminal signals, matter coupling inconsistencies and micro-acausality (propagation of signals around local closed timelike/causal curves). We extend previous no-go results to the entire three-parameter range of massive gravity theories. It is also argued that bimetric models suffer a similar fate.
Supersymmetrizing Massive Gravity
Malaeb, Ola
2013-01-01
When four scalar fields with global Lorentz symmetry are coupled to gravity and take a vacuum expectation value breaking diffeomorphism invariance spontaneously, the graviton becomes massive. This model is supersymmetrized by considering four N=1 chiral superfields with global Lorentz symmetry. When the scalar components of the chiral multiplets z^A acquire a vacuum expectation value, both diffeomorphism invariance and local supersymmetry are broken spontaneously. The global Lorentz index A becomes identified with the space-time Lorentz index making the scalar fields z^A vectors and the chiral spinors \\psi^A spin-3/2 Rarita-Schwinger fields. The global supersymmetry is promoted to a local one using the rules of tensor calculus of coupling the N=1 supergravity Lagrangian to the four chiral multiplets. We show that the spectrum of the model in the broken phase consists of a massive spin-2 field, two massive spin-3/2 fields with different mass and a massive vector.
Dereli, T.; Yetişmişoğlu, C.
2016-06-01
We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first-order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space AdS 3) and constant torsion provide exact solutions.
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Lin, Chunshan
2013-11-25
In this Letter, we propose a massive gravity theory with 5 degrees of freedom. The mass term is constructed by 3 Stückelberg scalar fields, which respects SO(3) symmetry in the fields' configuration. By the analysis on the linear cosmological perturbations, we found that such 5 d.o.f. are free from ghost instability, gradient instability, and tachyonic instability.
Dubovsky, Sergei L.
2004-10-01
We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity is described by a consistent low-energy effective theory with cutoff ~ (mMPl)1/2. This theory is free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of arbitrary higher dimension operators without assuming any fine-tunings among the coefficients of these operators, besides those enforced by the symmetries. These theories can be thought of as generalizations of the ghost condensate model with a smaller residual symmetry group. We briefly discuss what kind of cosmology can one expect in massive gravity and argue that the allowed values of the graviton mass may be quite large, affecting growth of primordial perturbations, structure formation and, perhaps, enhancing the backreaction of inhomogeneities on the expansion rate of the Universe.
Bergshoeff, Eric; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.
2014-01-01
We present an alternative to topologically massive gravity (TMG) with the same 'minimal' bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new 'minimal massive gravity'
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Morand, Kevin, E-mail: Kevin.Morand@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson - CNRS, Parc de Grandmont, 37200 Tours (France); Solodukhin, Sergey N., E-mail: Sergey.Solodukhin@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique, Universite Francois-Rabelais Tours, Federation Denis Poisson - CNRS, Parc de Grandmont, 37200 Tours (France)
2012-08-29
The linearized massive gravity in three dimensions, over any maximally symmetric background, is known to be presented in a self-dual form as a first order equation which encodes not only the massive Klein-Gordon type field equation but also the supplementary transverse-traceless conditions. We generalize this construction to higher dimensions. The appropriate dual description in d dimensions, additionally to a (non-symmetric) tensor field h{sub {mu}{nu}}, involves an extra rank-(d-1) field equivalently represented by the torsion rank-3 tensor. The symmetry condition for h{sub {mu}{nu}} arises on-shell as a consequence of the field equations. The action principle of the dual theory is formulated. The focus has been made on four dimensions. Solving one of the fields in terms of the other and putting back in the action one obtains two other equivalent formulations of the theory in which the action is quadratic in derivatives. In one of these representations the theory is formulated entirely in terms of a rank-2 non-symmetric tensor h{sub {mu}{nu}}. This quadratic theory is not identical to the Fierz-Pauli theory and contains the coupling between the symmetric and antisymmetric parts of h{sub {mu}{nu}}. Nevertheless, the only singularity in the propagator is the same as in the Fierz-Pauli theory so that only the massive spin-2 particle is propagating. In the other representation, the theory is formulated in terms of the torsion rank-3 tensor only. We analyze the conditions which follow from the field equations and show that they restrict to 5 degrees of freedom thus producing an alternative description to the massive spin-2 particle. A generalization to higher dimensions is suggested.
Higher dimensional nonlinear massive gravity
Do, Tuan Q
2016-01-01
Inspired by a recent ghost-free nonlinear massive gravity in four-dimensional spacetime, we study its higher dimensional scenarios. As a result, we are able to show the constant-like behavior of massive graviton terms for some well-known metrics such as the Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and Schwarzschild-Tangherlini-(A)dS metrics in a specific five-dimensional nonlinear massive gravity under an assumption that its fiducial metrics are compatible with physical ones. In addition, some simple cosmological solutions of the five-dimensional massive gravity will be figured out consistently.
Dubovsky, S L
2004-01-01
We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group using the explicitly covariant language. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity can be described by a consistent low-energy effective theory with cutoff $\\sim\\sqrt{mM_{Pl}}$ free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz--Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of ...
Massive Gravity in Three Dimensions
Bergshoeff, Eric A.; Hohm, Olaf; Townsend, Paul K.
2009-01-01
A particular higher-derivative extension of the Einstein-Hilbert action in three spacetime dimensions is shown to be equivalent at the linearized level to the (unitary) Pauli-Fierz action for a massive spin-2 field. A more general model, which also includes "topologically-massive" gravity as a speci
Quantum Corrections in Massive Gravity
de Rham, Claudia; Ribeiro, Raquel H
2013-01-01
We compute the one-loop quantum corrections to the potential of ghost-free massive gravity. We show how the mass of external matter fields contribute to the running of the cosmological constant, but do not change the ghost-free structure of the massive gravity potential at one-loop. When considering gravitons running in the loops, we show how the structure of the potential gets destabilized at the quantum level, but in a way which would never involve a ghost with a mass smaller than the Planck scale. This is done by explicitly computing the one-loop effective action and supplementing it with the Vainshtein mechanism. We conclude that to one-loop order the special mass structure of ghost-free massive gravity is technically natural.
Quantum corrections in massive gravity
de Rham, Claudia; Heisenberg, Lavinia; Ribeiro, Raquel H.
2013-10-01
We compute the one-loop quantum corrections to the potential of ghost-free massive gravity. We show how the mass of external matter fields contributes to the running of the cosmological constant, but does not change the ghost-free structure of the massive gravity potential at one-loop. When considering gravitons running in the loops, we show how the structure of the potential gets destabilized at the quantum level, but in a way which would never involve a ghost with a mass smaller than the Planck scale. This is done by explicitly computing the one-loop effective action and supplementing it with the Vainshtein mechanism. We conclude that to one-loop order the special mass structure of ghost-free massive gravity is technically natural.
Phase transitions in Bergshoeff-Hohm-Townsend massive gravity
Ghodrati, Mahdis; Naseh, Ali
2017-04-01
We present the Hawking-Page phase diagrams in the Bergshoeff-Hohm-Townsend (BHT) massive gravity theory for different solutions, such as the phase transitions between vacuum \\text{Ad}{{\\text{S}}3} and BTZ black hole, warped \\text{Ad}{{\\text{S}}3} and warped BTZ black hole in grand canonical and in non-local/quadratic ensembles, Lifshitz black hole and the new hairy black hole solutions. We observe that except for the black holes in quadratic ensemble, for other cases in the non-chiral theory of BHT the phase diagrams are symmetric with respect to the direction of angular momentum, as we expected. We conclude that for presenting the phase diagrams of warped \\text{Ad}{{\\text{S}}3} black holes, only the grand canonical ensemble should be used.
Modesto, Leonardo
2013-01-01
We present a general covariant action for massive gravity merging together a class of "non-polynomial" and super-renormalizable or finite theories of gravity with the non-local theory of gravity recently proposed by Jaccard, Maggiore and Mitsou (arXiv:1305.3034 [hep-th]). Our diffeomorphism invariant action gives rise to the equations of motion appearing in non-local massive massive gravity plus quadratic curvature terms. Not only the massive graviton propagator reduces smoothly to the massless one without a vDVZ discontinuity, but also our finite theory of gravity is unitary at tree level around the Minkowski background. We also show that, as long as the graviton mass $m$ is much smaller the today's Hubble parameter $H_0$, a late-time cosmic acceleration can be realized without a dark energy component due to the growth of a scalar degree of freedom. In the presence of the cosmological constant $\\Lambda$, the dominance of the non-local mass term leads to a kind of "degravitation" for $\\Lambda$ at the late cos...
Causality Constraints on Massive Gravity
Camanho, Xian O; Rahman, Rakibur
2016-01-01
The parameter space of the de Rham-Gabadadze-Tolley massive gravity ought to be constrained essentially to a line. The theory is shown to admit pp-wave backgrounds on which linear fluctuations otherwise undergo significant time advances, potentially leading to closed time-like curves. This classical phenomenon takes place well within the theory's validity regime.
Perturbations in Massive Gravity Cosmology
Crisostomi, Marco; Pilo, Luigi
2012-01-01
We study cosmological perturbations for a ghost free massive gravity theory formulated with a dynamical extra metric that is needed to massive deform GR. In this formulation FRW background solutions fall in two branches. In the dynamics of perturbations around the first branch solutions, no extra degree of freedom with respect to GR ispresent at linearized level, likewise what is found in the Stuckelberg formulation of massive gravity where the extra metric isflat and non dynamical. In the first branch, perturbations are probably strongly coupled. On the contrary, for perturbations around the second branch solutions all expected degrees of freedom propagate. While tensor and vector perturbations of the physical metric that couples with matter follow closely the ones of GR, scalars develop an exponential Jeans-like instability on sub-horizon scales. On the other hand, around a de Sitter background there is no instability. We argue that one could get rid of the instabilities by introducing a mirror dark matter ...
Minimal theory of massive gravity
De Felice, Antonio
2016-01-01
We propose a new theory of massive gravity with only two propagating degrees of freedom. After defining the theory in the unitary gauge in the vielbein language, we shall perform a Hamiltonian analysis to count the number of physical degrees of freedom, and then study some phenomenologies. While the homogeneous and isotropic background cosmology and the tensor linear perturbations around it are described by exactly the same equations as those in the de Rham - Gabadadze - Tolley (dRGT) massive gravity, the scalar and vector gravitational degrees of freedom are absent in the new theory at the fully nonlinear level. Hence the new theory provides a stable nonlinear completion of the self-accelerating cosmological solution that was originally found in the dRGT theory.
Causality in 3D Massive Gravity Theories
Edelstein, Jose D; Kilicarslan, Ercan; Leoni, Matias; Tekin, Bayram
2016-01-01
We study the constraints coming from local causality requirement in various 2+1 dimensional dynamical theories of gravity. In Topologically Massive Gravity, with a single parity noninvariant massive degree of freedom, and in New Massive Gravity, with two massive spin-$2$ degrees of freedom, causality and unitarity are compatible with each other and they both require the Newton's constant to be negative. In their extensions, such as the Born-Infeld gravity and the minimal massive gravity the situation is similar and quite different from their higher dimensional counterparts, such as quadratic (e.g., Einstein-Gauss-Bonnet) or cubic theories, where causality and unitarity are in conflict.
Solid Holography and Massive Gravity
Alberte, Lasma; Khmelnitsky, Andrei; Pujolas, Oriol
2015-01-01
Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric...
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Chacko, Z.; Graesser, M.L.; Grojean, C.; Pilo, L.
2003-12-11
At present no theory of a massive graviton is known that is consistent with experiments at both long and short distances. The problem is that consistency with long distance experiments requires the graviton mass to be very small. Such a small graviton mass however implies an ultraviolet cutoff for the theory at length scales far larger than the millimeter scale at which gravity has already been measured. In this paper we attempt to construct a model which avoids this problem. We consider a brane world setup in warped AdS spacetime and we investigate the consequences of writing a mass term for the graviton on a the infrared brane where the local cutoff is of order a large (galactic) distance scale. The advantage of this setup is that the low cutoff for physics on the infrared brane does not significantly affect the predictivity of the theory for observers localized on the ultraviolet brane. For such observers the predictions of this theory agree with general relativity at distances smaller than the infrared scale but go over to those of a theory of massive gravity at longer distances. A careful analysis of the graviton two-point function, however, reveals the presence of a ghost in the low energy spectrum. A mode decomposition of the higher dimensional theory reveals that the ghost corresponds to the radion field. We also investigate the theory with a brane localized mass for the graviton on the ultraviolet brane, and show that the physics of this case is similar to that of a conventional four dimensional theory with a massive graviton, but with one important difference: when the infrared brane decouples and the would-be massive graviton gets heavier than the regular Kaluza-Klein modes, it becomes unstable and it has a finite width to decay off the brane into the continuum of Kaluza-Klein states.
A massive graviton in topologically new massive gravity
Kim, Yong-Wan; Park, Young-Jai
2013-01-01
We investigate the topologically new massive gravity in three dimensions. It turns out that a single massive mode is propagating in the flat spacetime, comparing to the conformal Chern-Simons gravity which has no physically propagating degrees of freedom. Also we discuss the realization of the BMS/GCA correspondence.
Cosmological attractors in massive gravity
Dubovsky, S; Tkachev, I I
2005-01-01
We study Lorentz-violating models of massive gravity which preserve rotations and are invariant under time-dependent shifts of the spatial coordinates. In the linear approximation the Newtonian potential in these models has an extra ``confining'' term proportional to the distance from the source. We argue that during cosmological expansion the Universe may be driven to an attractor point with larger symmetry which includes particular simultaneous dilatations of time and space coordinates. The confining term in the potential vanishes as one approaches the attractor. In the vicinity of the attractor the extra contribution is present in the Friedmann equation which, in a certain range of parameters, gives rise to the cosmic acceleration.
A Cosmological Study in Massive Gravity theory
Pan, Supriya
2015-01-01
A detailed study of the various cosmological aspects in massive gravity theory has been presented in the present work. For the homogeneous and isotropic FLRW model, the deceleration parameter has been evaluated, and, it has been examined whether there is any transition from deceleration to acceleration in recent past, or not. With the proper choice of the free parameters, it has been shown that the massive gravity theory is equivalent to Einstein gravity with a modified Newtonian gravitational constant together with a negative cosmological constant. Also, in this context, it has been examined whether the emergent scenario is possible, or not, in massive gravity theory. Finally, we have done a cosmographic analysis in massive gravity theory.
Massive Gravity with N=1 local Supersymmetry
Malaeb, Ola
2013-01-01
A consistent theory of massive gravity, where the graviton acquires mass by spontaneously breaking diffeomorphism invariance, is now well established. We supersymmetrize this construction using N =1 fields. Coupling to N = 1 supergravity is done by applying the rules of tensor calculus to construct an action invariant under local N = 1 supersymmetry. The supersymmetric action is shown, at the quadratic level, to be free of ghosts and have as its spectrum a massive graviton, two gravitinos with different masses, and a massive vector.
Holographically Viable Extensions of Topologically Massive and Minimal Massive Gravity?
Altas, Emel
2015-01-01
Recently, an extension of the topologically massive gravity (TMG) in $2+1$ dimensions, dubbed as minimal massive gravity (MMG), was found which is free of the bulk-boundary unitarity clash that inflicts the former theory and all the other known three dimensional theories. Field equations of MMG differ from those of TMG at quadratic terms in the curvature that do not come from the variation of an action depending on the metric alone. Here we show that MMG is a unique theory and there does not exist a deformation of TMG or MMG at the cubic and quartic order (and beyond) in the curvature that is consistent at the level of the field equations. The only extension of TMG with the desired bulk and boundary properties having a single massive degree of freedom is MMG.
Charged Black Holes in New Massive Gravity
Ghodsi, Ahmad; Moghadassi, Mohammad
2010-01-01
We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.
New Bi-Gravity from New Massive Gravity
Akhavan, A.; Alishahiha, M.; Naseh, A.; Nemati, A.; Shirzad, A.
2016-05-01
Using the action of three dimensional New Massive Gravity (NMG) we construct a new bi-gravity in three dimensions. This can be done by promoting the rank two auxiliary field appearing in the expression of NMG's action into a dynamical field. We show that small fluctuations around the AdS vacuum of the model are non-tachyonic and ghost free within certain range of the parameters of the model. We study central charges of the dual field theory and observe that in this range they are positive too. This suggests that the proposed model might be a consistent three dimensional bi-gravity.
Nonlinear Properties of Vielbein Massive Gravity
Nibbelink, S G; Sexton, M; Nibbelink, Stefan Groot; Peloso, Marco; Sexton, Matthew
2006-01-01
We consider a special theory of massive gravity, which is obtained in a decoupling limit from a bi-gravity theory in the vielbein formulation, with only cosmological constant-like interactions between the two gravitational sectors. We investigate this theory using the Stueckelberg method, and construct a 't Hooft-Feynman gauge fixing in which the tensor, vector and scalar Stueckelberg fields are decoupled. We prove that this model has the softest possible ultraviolet behavior which can be expected from any generic (Lorentz invariant) theory of massive gravity, namely that it becomes strong only at the scale Lambda_3 = (m_g^2 M_P)^{1/3} . Finally, we confirm that also this model is plagued by a ghost instability, which, in the Stueckelberg formalism, arises from quartic scalar-vector and scalar-tensor interactions.
Charged Black Holes in Massive Gravity's Rainbow
Hendi, S H; Panahiyan, S
2016-01-01
Violation of Lorentz invariancy in the high energy quantum gravity, motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of the solutions and show that that there is a curvature singularity at the origin ($r=0$) which can be covered with an event horizon. We also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. Finally, we examine the validity of the first law of thermodynamics. Next, we conduct a study regarding the positivity and negativity of total mass in de Sitter and anti de Sitter spacetime.
Cosmological Perturbations in Extended Massive Gravity
Gumrukcuoglu, A Emir; Lin, Chunshan; Mukohyama, Shinji; Trodden, Mark
2013-01-01
We study cosmological perturbations around self-accelerating solutions to two extensions of nonlinear massive gravity: the quasi-dilaton theory and the mass-varying theory. We examine stability of the cosmological solutions, and the extent to which the vanishing of the kinetic terms for scalar and vector perturbations of self-accelerating solutions in massive gravity is generic when the theory is extended. We find that these kinetic terms are in general non-vanishing in both extensions, though there are constraints on the parameters and background evolution from demanding that they have the correct sign. In particular, the self-accelerating solutions of the quasi-dilaton theory are always unstable to scalar perturbations with wavelength shorter than the Hubble length.
Gravitational wave signal from massive gravity
Gumrukcuoglu, A Emir; Lin, Chunshan; Mukohyama, Shinji; Tanahashi, Norihiro
2012-01-01
We discuss the detectability of gravitational waves with a time dependent mass contribution, by means of the stochastic gravitational wave observations. Such a mass term typically arises in the cosmological solutions of massive gravity theories. We conduct the analysis based on a general quadratic action, and thus the results apply universally to any massive gravity theories in which modification of general relativity appears primarily in the tensor modes. The primary manifestation of the modification in the gravitational wave spectrum is a sharp peak. The position and height of the peak carry information on the present value of the mass term, as well as the duration of the inflationary stage. We also discuss the detectability of such a gravitational wave signal using the future-planned gravitational wave observatories.
Exact Spherically Symmetric Solutions in Massive Gravity
Berezhiani, Z; Nesti, F; Pilo, L
2008-01-01
A phase of massive gravity free from pathologies can be obtained by coupling the metric to an additional spin-two field. We study the gravitational field produced by a static spherically symmetric body, by finding the exact solution that generalizes the Schwarzschild metric to the case of massive gravity. Besides the usual 1/r term, the main effects of the new spin-two field are a shift of the total mass of the body and the presence of a new power-like term, with sizes determined by the mass and the shape (the radius) of the source. These modifications, being source dependent, give rise to a dynamical violation of the Strong Equivalence Principle. Depending on the details of the coupling of the new field, the power-like term may dominate at large distances or even in the ultraviolet. The effect persists also when the dynamics of the extra field is decoupled.
Chiral gravity as a covariant formulation of massive gravity
Nibbelink, S G; Nibbelink, Stefan Groot; Peloso, Marco
2004-01-01
We present a covariant nonlinear completion of the Fierz-Pauli (FP) mass term for the graviton. The starting observation is that the FP mass is immediately obtained by expanding the cosmological constant term, i.e. the determinant of the vielbein, around Minkowski space to second order in the vielbein perturbations. Since this is an unstable expansion in the standard case, we consider an extended theory of gravity which describes two vielbeins that give rise to chiral spin--connections (consequently, fermions of a definite chirality only couple to one of the gravitational sectors). As for Einstein gravity with a cosmological constant, a single fine-tuning is needed to recover a Minkowski background; the two sectors then differ only by a constant conformal factor. The spectrum of this theory consists of a massless and a massive graviton, with FP mass term. The theory possesses interesting limits in which only the massive graviton is coupled to matter at the linearized level.
Embeddings of the "New Massive Gravity"
Dalmazi, D.; Mendonça, E. L.
2016-07-01
Here we apply different types of embeddings of the equations of motion of the linearized "New Massive Gravity" in order to generate alternative and even higher-order (in derivatives) massive gravity theories in D=2+1. In the first part of the work we use the Weyl symmetry as a guiding principle for the embeddings. First we show that a Noether gauge embedding of the Weyl symmetry leads to a sixth-order model in derivatives with either a massive or a massless ghost, according to the chosen overall sign of the theory. On the other hand, if the Weyl symmetry is implemented by means of a Stueckelberg field we obtain a new scalar-tensor model for massive gravitons. It is ghost-free and Weyl invariant at the linearized level around Minkowski space. The model can be nonlinearly completed into a scalar field coupled to the NMG theory. The elimination of the scalar field leads to a nonlocal modification of the NMG. In the second part of the work we prove to all orders in derivatives that there is no local, ghost-free embedding of the linearized NMG equations of motion around Minkowski space when written in terms of one symmetric tensor. Regarding that point, NMG differs from the Fierz-Pauli theory, since in the latter case we can replace the Einstein-Hilbert action by specific f(R,Box R) generalizations and still keep the theory ghost-free at the linearized level.
Ghost free massive gravity with singular reference metrics
Zhang, Hongsheng; Li, Xin-Zhou
2016-06-01
An auxiliary metric (reference metric) is inevitable in massive gravity theory. In the scenario of the gauge/gravity duality, massive gravity with a singular reference metric is used to study momentum dissipation, which describes the electric and heat conductivity for normal conductors. We demonstrate in detail that the de Rham-Gabadadze-Tolley (dRGT) massive gravity with a singular reference metric is ghost free.
Phenomenology in minimal theory of massive gravity
Energy Technology Data Exchange (ETDEWEB)
Felice, Antonio De [Yukawa Institute for Theoretical Physics, Kyoto University,606-8502, Kyoto (Japan); Mukohyama, Shinji [Yukawa Institute for Theoretical Physics, Kyoto University,606-8502, Kyoto (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo,277-8583, Chiba (Japan)
2016-04-15
We investigate the minimal theory of massive gravity (MTMG) recently introduced. After reviewing the original construction based on its Hamiltonian in the vielbein formalism, we reformulate it in terms of its Lagrangian in both the vielbein and the metric formalisms. It then becomes obvious that, unlike previous attempts in the literature of Lorentz-violating massive gravity, not only the potential but also the kinetic structure of the action is modified from the de Rham-Gabadadze-Tolley (dRGT) massive gravity theory. We confirm that the number of physical degrees of freedom in MTMG is two at fully nonlinear level. This proves the absence of various possible pathologies such as superluminality, acausality and strong coupling. Afterwards, we discuss the phenomenology of MTMG in the presence of a dust fluid. We find that on a flat homogeneous and isotropic background we have two branches. One of them (self-accelerating branch) naturally leads to acceleration without the genuine cosmological constant or dark energy. For this branch both the scalar and the vector modes behave exactly as in general relativity (GR). The phenomenology of this branch differs from GR in the tensor modes sector, as the tensor modes acquire a non-zero mass. Hence, MTMG serves as a stable nonlinear completion of the self-accelerating cosmological solution found originally in dRGT theory. The other branch (normal branch) has a dynamics which depends on the time-dependent fiducial metric. For the normal branch, the scalar mode sector, even though as in GR only one scalar mode is present (due to the dust fluid), differs from the one in GR, and, in general, structure formation will follow a different phenomenology. The tensor modes will be massive, whereas the vector modes, for both branches, will have the same phenomenology as in GR.
Propagation peculiarities of mean field massive gravity
Directory of Open Access Journals (Sweden)
S. Deser
2015-10-01
Full Text Available Massive gravity (mGR describes a dynamical “metric” on a fiducial, background one. We investigate fluctuations of the dynamics about mGR solutions, that is about its “mean field theory”. Analyzing mean field massive gravity (m‾GR propagation characteristics is not only equivalent to studying those of the full non-linear theory, but also in direct correspondence with earlier analyses of charged higher spin systems, the oldest example being the charged, massive spin 3/2 Rarita–Schwinger (RS theory. The fiducial and mGR mean field background metrics in the m‾GR model correspond to the RS Minkowski metric and external EM field. The common implications in both systems are that hyperbolicity holds only in a weak background-mean-field limit, immediately ruling both theories out as fundamental theories; a situation in stark contrast with general relativity (GR which is at least a consistent classical theory. Moreover, even though both m‾GR and RS theories can still in principle be considered as predictive effective models in the weak regime, their lower helicities then exhibit superluminal behavior: lower helicity gravitons are superluminal as compared to photons propagating on either the fiducial or background metric. Thus our approach has uncovered a novel, dispersive, “crystal-like” phenomenon of differing helicities having differing propagation speeds. This applies both to m‾GR and mGR, and is a peculiar feature that is also problematic for consistent coupling to matter.
Topologically Massive Gravity from the Heterotic String
Lu, H
2010-01-01
Topologically massive gravity (TMG) in three dimensions provides an interesting toy model for constructing a quantum theory of gravity. Although it can be thought of as standing as a theory in its own right, it is also of interest to see whether it can be described within the larger framework of string theory or M-theory. In this paper, we show that it can be embedded within the heterotic string, via a compactification on $S^3\\times T^4$. Since all solutions of TMG can now be lifted to ten dimensions, this allows us to give a string and brane interpretation to quantities such as the central charges in the conformal field theory on the boundary of TMG, and the entropy of the BTZ black hole solution.
A new quasidilaton theory of massive gravity
Mukohyama, Shinji
2014-01-01
We present a new quasidilaton theory of Poincare invariant massive gravity, based on the recently proposed framework of matter coupling that makes it possible for the kinetic energy of the quasidilaton scalar to couple to both physical and fiducial metrics simultaneously. We find a scaling-type exact solution that expresses a self-accelerating de Sitter universe, and then analyze linear perturbations around it. It is shown that in a range of parameters all physical degrees of freedom have non-vanishing quadratic kinetic terms and are stable in the subhorizon limit, while the effective Newton's constant for the background is kept positive.
New Cosmological Solutions in Massive Gravity Theory
Pinho, S. S. A.; Pereira, S. H.; Mendonça, E. L.
2017-04-01
In this paper we present some new cosmological solutions in massive gravity theory. Some homogeneous and isotropic solutions correctly describe accelerated evolutions for the universe. The study was realized considering a specific form to the fiducial metric and found different functions and constant parameters of the theory that guarantee the conservation of the energy momentum tensor. Several accelerating cosmologies were found, all of them reproducing a cosmological constant term proportional to the graviton mass, with a de Sitter type solution for the scale factor. We have also verified that when the fiducial metric is close to the physical metric the solutions are absent, except for some specific open cases.
Hamiltonian cosmology in bigravity and massive gravity
Soloviev, Vladimir O
2015-01-01
In the Hamiltonian language we provide a study of flat-space cosmology in bigravity and massive gravity constructed mostly with de Rham, Gabadadze, Tolley (dRGT) potential. It is demonstrated that the Hamiltonian methods are powerful not only in proving the absence of the Boulware-Deser ghost, but also in solving other problems. The purpose of this work is to give an introduction both to the Hamiltonian formalism and to the cosmology of bigravity. We sketch three roads to the Hamiltonian of bigravity with the dRGT potential: the metric, the tetrad and the minisuperspace approaches.
Drag phenomena from holographic massive gravity
Baggioli, Matteo; Brattan, Daniel K.
2017-01-01
We consider the motion of point particles in a strongly coupled field theory with broken translation invariance. We obtain the energy and momentum loss rates and drag coefficients for a class of such particles by solving for the motion of classical strings in holographic massive gravity. At low temperatures compared to the graviton mass the behaviour of the string is controlled by the appearance of an exotic ground state with non-zero entropy at zero temperature. Additionally, we find an upper bound on the diffusion constant for a collection of these particles which is saturated when the mass of the graviton goes to zero.
Drag phenomena from holographic massive gravity
Baggioli, Matteo
2015-01-01
We consider the motion of point particles in a strongly coupled field theory with broken translation invariance. We obtain the energy and momentum loss rates and drag coefficients for a class of such particles by solving for the motion of classical strings in holographic massive gravity. At low temperatures compared to the graviton mass the behaviour of the string is controlled by the appearance of an exotic ground state with non-zero entropy at zero temperature. Additionally we find an upper bound on the diffusion constant for a collection of these particles which is saturated when the mass of the graviton goes to zero.
Embeddings of the "New Massive Gravity"
Dalmazi, D
2016-01-01
Using different types of embeddings of equations of motion we investigate the existence of generalizations of the "New Massive Gravity" (NMG) model with the same particle content (massive gravitons). By using the Weyl symmetry as a guiding principle for the embeddings we show that the Noether gauge embedding approach leads us to a sixth order model in derivatives with either a massive or a massless ghost. If the Weyl symmetry is implemented by means of a Stueckelberg field we obtain a new scalar-tensor model for massive gravitons. It is ghost free and Weyl invariant at linearized level. The model can be nonlinearly completed into a scalar field coupled to the NMG theory. The elimination of the scalar field leads to a nonlocal modification of the NMG. We also prove to all orders in derivatives that there is no local, ghost free embedding of the linearized NMG equations of motion around Minkowski space when written in terms of one symmetric tensor. Regarding that point, NMG differs from the Fierz-Pauli theory, ...
KPZ Formulas for Weyl-Invariant Induced Gravity and Topologically Massive Gravity
Amelino-Camelia, G.
1997-01-01
I discuss the applicability in Weyl-invariant induced gravity and topologically massive gravity of certain formulas originally derived by Knizhnik, Polyakov, and Zamolodchikov in the context of diffeomorphism-invariant induced gravity.
KPZ Formulas for Weyl-Invariant Induced Gravity and Topologically Massive Gravity
Amelino-Camelia, G.
1997-01-01
I discuss the applicability in Weyl-invariant induced gravity and topologically massive gravity of certain formulas originally derived by Knizhnik, Polyakov, and Zamolodchikov in the context of diffeomorphism-invariant induced gravity.
Phenomenology in minimal theory of massive gravity
De Felice, Antonio
2015-01-01
We investigate the minimal theory of massive gravity (MTMG) recently introduced. After reviewing the original construction based on its Hamiltonian in the vielbein formalism, we reformulate it in terms of its Lagrangian in both the vielbein and the metric formalisms. It then becomes obvious that, unlike previous attempts in the literature, not only the potential but also the kinetic structure of the action is modified from the de Rham-Gabadadze-Tolley (dRGT) massive gravity theory. We confirm that the number of physical degrees of freedom in MTMG is two at fully nonlinear level. This proves the absence of various possible pathologies such as superluminality, acausality and strong coupling. Afterwards, we discuss the phenomenology of MTMG in the presence of a dust fluid. We find that on a flat homogeneous and isotropic background we have two branches. One of them (self-accelerating branch) naturally leads to acceleration without the genuine cosmological constant or dark energy. For this branch both the scalar ...
Does massive gravity have viable cosmologies?
Solomon, Adam R; Akrami, Yashar; Koivisto, Tomi S; Könnig, Frank; Mörtsell, Edvard
2015-01-01
Massive gravity has a well-known no-go theorem forbidding flat FLRW solutions; other solutions are unstable, seemingly ruling out the possibility of homogeneous and isotropic massive cosmology. Recently, de Rham, Heisenberg, and Ribeiro showed that this can be overcome if matter is coupled to both the spacetime metric and the reference metric, reopening the possibilities for cosmology with a single, massive graviton. It is shown that this proof, however, relies crucially on the existence of a scalar field or some other nonstandard matter, while a universe filled with only dust or radiation faces the same no-go restriction as in the original theory. Unusually, the total density, pressure, and Einstein-frame Friedmann equation are completely determined in terms of the scale factor, independent of the matter content; the physical Hubble rate, however, does not have this property. In the presence of a scalar, these models possess pathological evolution at both early and late times, unless the scalar has a highly ...
Revisiting perturbations in extended quasidilaton massive gravity
Heisenberg, Lavinia
2015-04-01
In this work we study the theory of extended quasidilaton massive gravity together with the presence of matter fields. After discussing the homogeneous and isotropic fully dynamical background equations, which governs the exact expansion history of the universe, we consider small cosmological perturbations around these general FLRW solutions. The stability of tensor, vector and scalar perturbations on top of these general background solutions give rise to slightly different constraints on the parameters of the theory than those obtained in the approximative assumption of the late-time asymptotic form of the expansion history, which does not correspond to our current epoch. This opens up the possibility of stable FLRW solutions to be compared with current data on cosmic expansion with the restricted parameter space based on theoretical ground.
Holographic Josephson Junction from Massive Gravity
Hu, Ya-Peng; Zeng, Hua-Bi; Zhang, Hai-Qing
2015-01-01
We study the holographic superconductor-normal metal-superconductor (SNS) Josephon junction in the massive gravity. In the homogeneous case of the chemical potential, we find that the graviton mass will make the normal metal-superconductor phase transition harder to take place. In the holographic model of Josephson junction, it is found that the maximal tunneling current will decrease according to the graviton mass. Besides, the coherence length of the junction decreases as well with respect to the graviton mass. If one interprets the graviton mass as the effect of momentum dissipation in the boundary field theory, it indicates that the stronger the momentum dissipation is, the smaller the coherence length is.
Cosmic expansion in extended quasidilaton massive gravity
Kahniashvili, Tina; Kar, Arjun; Lavrelashvili, George; Agarwal, Nishant; Heisenberg, Lavinia; Kosowsky, Arthur
2015-02-01
Quasidilaton massive gravity offers a physically well-defined gravitational theory with nonzero graviton mass. We present the full set of dynamical equations governing the expansion history of the Universe, valid during radiation domination, matter domination, and a late-time self-accelerating epoch related to the graviton mass. The existence of self-consistent solutions constrains the amplitude of the quasidilaton field and the graviton mass, as well as other model parameters. We point out that the effective mass of gravitational waves can be significantly larger than the graviton mass, opening the possibility that a single theory can explain both the late-time acceleration of cosmic expansion and modifications of structure growth leading to the suppression of large-angle correlations observed in the cosmic microwave background.
Revisiting perturbations in extended quasidilaton massive gravity
Heisenberg, Lavinia
2015-01-01
In this work we study the theory of extended quasidilaton massive gravity together with the presence of matter fields. After discussing the homogeneous and isotropic fully dynamical background equations, which governs the exact expansion history of the universe, we consider small cosmological perturbations around these general FLRW solutions. The stability of tensor, vector and scalar perturbations on top of these general background solutions give rise to slightly different constraints on the parameters of the theory than those obtained in the approximative assumption of the late-time asymptotic form of the expansion history, which does not correspond to our current epoch. This opens up the possibility of stable FLRW solutions to be compared with current data on cosmic expansion with the restricted parameter space based on theoretical ground.
Cosmic Expansion in Extended Quasidilaton Massive Gravity
Kahniashvili, Tina; Lavrelashvili, George; Agarwal, Nishant; Heisenberg, Lavinia; Kosowsky, Arthur
2014-01-01
Quasidilaton massive gravity offers a physically well-defined gravitational theory with non-zero graviton mass. We present the full set of dynamical equations governing the expansion history of the universe, valid during radiation domination, matter domination, and a late-time self-accelerating epoch related to the graviton mass. The existence of self-consistent solutions constrains the amplitude of the quasi-dilaton field and the graviton mass, as well as other model parameters. We point out that the effective mass of gravitational waves can be significantly larger than the graviton mass, opening the possibility that a single theory can explain both the late-time acceleration of the cosmic expansion and modifications of structure growth leading to the suppression of large-angle correlations observed in the cosmic microwave background.
FRW Cosmology in Ghost Free Massive Gravity
Comelli, D; Nesti, F; Pilo, L
2011-01-01
We study FRW homogeneous cosmological solutions in the recently found ghost free massive gravity. In previous works it was shown that when the additional extra metric, needed to generate the mass term, is taken as non-dynamical and flat, no homogeneous FRW cosmology exists. We show that, when the additional metric is a dynamical field, a perfectly safe FRW universe exists. FRW solutions fall in two branches. In the first branch the massive deformation is equivalent to an effectively generated cosmological constant whose scale is determined by the graviton mass. The second branch is quite rich: we have FRW cosmology in the presence of a "gravitational" fluid. The control parameter xi is the ratio of the two conformal factors. When xi is large, generically the cosmological evolution greatly differs from GR at the early time. In the small xi region, the evolution is similar to GR and the universe flows at late time toward an attractor represented by a dS phase.
Mirza, Behrouz
2011-01-01
We study the AdS rotating black hole solution for the Bergshoeff-Hohm-Townsend (BHT) massive gravity in three dimensions. The field equations of the asymptotically AdS black hole of the static metric can be expressed as the first law of thermodynamics, i.e. $dE=TdS-PdV$. The corrected Hawking-like temperature and entropy of asymptotically AdS rotating black hole are calculated using the Cardy formula and the tunneling method. Comparison of these methods will help identify the unknown leading correction parameter $\\beta_1$ in the tunneling method.
Neutron stars structure in the context of massive gravity
Hendi, S. H.; Bordbar, G. H.; Eslam Panah, B.; Panahiyan, S.
2017-07-01
Motivated by the recent interests in spin-2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.
Massive Nordstr\\"om Scalar (Density) Gravities from Universal Coupling
Pitts, J Brian
2010-01-01
Both particle physics and the 1890s Seeliger-Neumann modification of Newtonian gravity suggest considering a "mass term" for gravity, yielding a finite range due to an exponentially decaying Yukawa potential. Unlike Nordstr\\"{o}m's "massless" theory, massive scalar gravities are strictly Special Relativistic, being invariant under the Poincar\\'{e} group but not the conformal group. Geometry is a poor guide to understanding massive scalar gravities: matter sees a conformally flat metric, but gravity also sees the rest of the flat metric, barely, in the mass term. Infinitely many theories exhibit this bimetric 'geometry,' all with the total stress-energy's trace as source. All are new except the Freund-Nambu theory. The smooth massless limit indicates underdetermination of theories by data between massless and massive scalar gravities. The ease of accommodating electrons, protons and other fermions using density-weighted Ogievetsky-Polubarinov spinors in scalar gravity is noted.
Stability of massive graviton around BTZ black hole in three dimensional massive gravities
Moon, Taeyoon
2013-01-01
We investigate the massive graviton stability of the BTZ black hole obtained from three dimensional massive gravities which are classified into the parity-even and parity-odd gravity theories. In the parity-even gravity theory, we perform the $s$-mode stability analysis by using the BTZ black string perturbations, which gives two Schr\\"odinger equations with frequency-dependent potentials. The $s$-mode stability is consistent with the generalized Breitenlohner-Freedman bound for spin-2 field. It seems that for the parity-odd massive gravity theory, the BTZ black hole is stable when the imaginary part of quasinormal frequencies of massive graviton is positive. However, this condition is not consistent with the $s$-mode stability based on the second-order equation obtained after squaring the first-order equation. Finally we explore the black hole stability connection between the parity-odd and parity-even massive gravity theories.
Matter coupling in 3D "Minimal Massive Gravity"
Arvanitakis, Alex S; Townsend, Paul K
2014-01-01
The "Minimal Massive Gravity" (MMG) model of massive gravity in three spacetime dimensions (which has the same anti-de Sitter (AdS) bulk properties as "Topologically Massive Gravity" but improved boundary properties) is coupled to matter. Consistency requires a particular matter source tensor, which is quadratic in the stress tensor. The consequences are explored for an ideal fluid in the context of asymptotically de-Sitter (dS) cosmological solutions, which bounce smoothly from contraction to expansion. Various vacuum solutions are also found, including warped-(A)dS, and (for special values of parameters) static black holes and an (A)dS2 x S1 vacuum.
Cosmological solutions of massive gravity on de Sitter
Langlois, David
2012-01-01
In the framework of the recently proposed models of massive gravity, but defined with respect to a de Sitter reference metric, we obtain new homogeneous and isotropic solutions for arbitrary spatial curvature. These solutions can be classified into three branches. In the first two, the massive gravity terms behave like a cosmological constant. In the third branch, the massive gravity effects can be described by a time evolving effective fluid with rather remarkable features, including the property to behave as a cosmological constant at low energy, when the Hubble parameter decreases below a critical value.
Cosmology of the Galileon from Massive Gravity
de Rham, Claudia
2011-01-01
We covariantize the decoupling limit of massive gravity proposed in arXiv:1011.1232 and study the cosmology of this theory as a proxy, which embodies key features of the fully non-linear covariant theory. We first confirm that it exhibits a self-accelerating solution, similar to what has been found in arXiv:1010.1780, where the Hubble parameter corresponds to the graviton mass. For a certain range of parameters fluctuations relative to the self-accelerating background are stable and form an attractor solution. We also show that a degravitating solution can not be constructed in this covariantized proxy theory in a meaningful way. As for cosmic structure formation, we find that the helicity-0 mode of the graviton causes an enhancement relative to LCDM. For consistency we also compare proxy theories obtained starting from different frames in the decoupling limit and discuss the possibility of obtaining a non-representative proxy theory by choosing the wrong starting frame.
Cosmology of the Galileon from massive gravity
de Rham, Claudia; Heisenberg, Lavinia
2011-08-01
We covariantize the decoupling limit of massive gravity proposed in [de Rham, G. Gabadadze, and A. J. Tolley, Phys. Rev. Lett. 106, 231101 (2011).PRLTAO0031-900710.1103/PhysRevLett.106.231101] and study the cosmology of this theory as a proxy, which embodies key features of the fully nonlinear covariant theory. We first confirm that it exhibits a self-accelerating solution, similar to what has been found in [C. de Rham, G. Gabadadze, L. Heisenberg, and D. Pirtskhalava, Phys. Rev. DPRVDAQ1550-7998 83, 103516 (2011).10.1103/PhysRevD.83.103516], where the Hubble parameter corresponds to the graviton mass. For a certain range of parameters fluctuations relative to the self-accelerating background are stable and form an attractor solution. We also show that a degravitating solution can not be constructed in this covariantized proxy theory in a meaningful way. As for cosmic structure formation, we find that the helicity-0 mode of the graviton causes an enhancement relative to ΛCDM. For consistency we also compare proxy theories obtained starting from different frames in the decoupling limit and discuss the possibility of obtaining a nonrepresentative proxy theory by choosing the wrong starting frame.
On the cosmology of massive gravity
De Felice, Antonio; Lin, Chunshan; Mukohyama, Shinji
2013-01-01
We present a review of cosmological solutions in non-linear massive gravity, focusing on the stability of perturbations. Although homogeneous and isotropic solutions have been found, these are now known to suffer from either Higuchi ghost or a new non-linear ghost instability. We discuss two approaches to alleviate this issue. By relaxing the symmetry of the background by e.g. breaking isotropy in the hidden sector, it is possible to accommodate a stable cosmological solution. Alternatively, extending the theory to allow for new dynamical degrees of freedom can also remove the conditions which lead to the instability. As examples for this case, we study the stability of self-accelerating solutions in the quasi-dilatonic extension and generic cosmological solutions in the varying mass extension. While the quasi-dilaton case turns out to be unstable, the varying mass case allows stable regimes of parameters. Viable self-accelerating solutions in the varying mass theory yet remain to be found.
Charged black hole solutions in Gauss-Bonnet-massive gravity
National Research Council Canada - National Science Library
Hendi, S H; Panahiyan, S; Panah, B Eslam
2016-01-01
Motivated by high interest in the close relation between string theory and black hole solutions, in this paper, we take into account the Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity...
A spin-4 analog of 3D massive gravity
Bergshoeff, Eric A.; Kovacevic, Marija; Rosseel, Jan; Townsend, Paul K.; Yin, Yihao
2011-01-01
A sixth-order, but ghost-free, gauge-invariant action is found for a fourth-rank symmetric tensor potential in a three-dimensional (3D) Minkowski spacetime. It propagates two massive modes of spin 4 that are interchanged by parity and is thus a spin-4 analog of linearized 'new massive gravity'. Also
First Order Actions for New Massive Dual Gravities
Bracho, Alexangel
2013-01-01
We present a first order formulation for the fourth order action of the new massive dual gravity in four dimensions. This proposal is easily generalized to arbitrary dimension. Also, we obtain the dual actions for massless and massive Curtright fields in D dimensions.
Cosmology of the proxy theory to massive gravity
Heisenberg, Lavinia; Yamamoto, Kazuhiro
2014-01-01
In this paper, we scrutinize very closely the cosmology in the proxy theory to massive gravity obtained in Phys. Rev. D84 (2011) 043503. This proxy theory was constructed by covariantizing the decoupling limit Lagrangian of massive gravity and represents a subclass of Horndeski scalar-tensor theory. Thus, this covariantization unifies two important classes of modified gravity theories, namely massive gravity and Horndeski theories. We go beyond the regime which was studied in Phys. Rev. D84 (2011) 043503 and show that the theory does not admit any homogeneous and isotropic self-accelerated solutions. We illustrate that the only attractor solution is flat Minkowski solution, hence this theory is less appealing as a dark energy model. We also show that the absence of de Sitter solutions is tightly related to the presence of shift symmetry breaking interactions.
Cosmology of the proxy theory to massive gravity
Heisenberg, Lavinia; Kimura, Rampei; Yamamoto, Kazuhiro
2014-05-01
In this paper, we scrutinize very closely the cosmology in the proxy theory to massive gravity obtained in de Rham and Heisenberg [Phys. Rev. D 84, 043503 (2011)]. This proxy theory was constructed by covariantizing the decoupling limit Lagrangian of massive gravity, and it represents a subclass of Horndeski scalar-tensor theory. Thus, this covariantization unifies two important classes of modified gravity theories, namely, massive gravity and Horndeski theories. We go beyond the regime which was studied in de Rham and Heisenberg [Phys. Rev. D 84, 043503 (2011)] and show that the theory does not admit any homogeneous and isotropic self-accelerated solutions. We illustrate that the only attractor solution is the flat Minkowski solution; hence, this theory is less appealing as a dark energy model. We also show that the absence of de Sitter solutions is tightly related to the presence of shift symmetry breaking interactions.
Holographic complexity and action growth in massive gravities
Pan, Wen-Jian; Huang, Yong-Chang
2017-06-01
In this paper, we investigate the growth rates of action for the anti-de Sitter black holes in massive-Einstein gravity models and obtain the universal behaviors of the growth rates of action (the rates of holographic complexity) within the "Wheeler-DeWitt" (WDW) patch at the late limit. Furthermore, we find that, for the static neutral cases, when the same mass of black holes is given, the computational speed of the neutral massive black hole is the same as its Einstein gravity counterpart, which is independent with the effect of the graviton mass terms; nevertheless, for the static charged cases, when the same mass and charge parameters of black holes are given, the growth rates of action for the massive charged black holes are always superior to the growth rates of action without graviton mass terms, which directly shows that the massive charged black holes as computers on the computational speeds are faster than their Einstein gravity counterparts.
Massive gravitons from Extended Gravity to Effective Field Theories
Capozziello, Salvatore; Paolella, Mariacristina; Ricciardi, Giulia
2013-01-01
Massive gravitons in effective field theories can be recovered by extending General Relativity and taking into account generic functions of the curvature invariants not necessarily linear in the Ricci scalar R. In particular, adopting the minimal extension of f(R) gravity, an effective field theory with a massive state is straightforwardly recovered. This approach allows to evade shortcomings like ghosts and discontinuities if a suitable choice of expansion parameters is performed. We show that the massive state can be identified with a massive graviton.
Dirac field in topologically massive gravity
Sert, Özcan; Adak, Muzaffer
2013-01-01
We consider a Dirac field coupled minimally to the Mielke-Baekler model of gravity and investigate cosmological solutions in three dimensions. We arrive at a family of solutions which exists even in the limit of vanishing cosmological constant.
Phase transitions of black holes in massive gravity
Fernando, Sharmanthie
2016-01-01
In this paper we have studied thermodynamics of a black hole in massive gravity in the canonical ensemble. The massive gravity theory in consideration here has a massive graviton due to Lorentz symmetry breaking. The black hole studied here has a scalar charge due to the massive graviton and is asymptotically anti-de Sitter. We have computed various thermodynamical quantities such as temperature, specific heat and free energy. Both the local and global stability of the black hole are studied by observing the behavior of the specific heat and the free energy. We have observed that there is a first order phase transition between small and large black hole for a certain range of the scalar charge. This phase transition is similar to the liquid/gas phase transition at constant temperature for a Van der Waals fluid. The coexistence curves for the small and large black hole branches are also discussed in detail.
Massive gravity coupled to DBI Galileons is ghost free
Andrews, Melinda; Hinterbichler, Kurt; Stokes, James; Trodden, Mark
2013-01-01
It is possible to couple Dirac-Born-Infeld (DBI) scalars possessing generalized Galilean internal shift symmetries (Galileons) to nonlinear massive gravity in four dimensions, in such a manner that the interactions maintain the Galilean symmetry. Such a construction is of interest because it is not possible to couple such fields to massless General Relativity in the same way. We show that this theory has the primary constraint necessary to eliminate the Boulware-Deser ghost, thus preserving the attractive properties of both the Galileons and ghost-free massive gravity.
Solar system tests for linear massive conformal gravity
Faria, F F
2016-01-01
We first find the linearized gravitational field of a static spherically symmetric mass distribution in massive conformal gravity. Then we test this field with two solar system experiments: deflection of light by the sun and radar echo delay. The result is that the linear massive conformal gravity agrees with the linear general relativistic observations in the solar system. However, besides the standard general relativistic deflection of light, the theory gives an extra deflection at galactic scales. It is likely that this additional deflection replaces the effects of dark matter in general relativity.
Infrared Behaviour of Massive Scalar Matter coupled to Gravity
Wellmann, M
2001-01-01
In the framework of causal perturbation theory we consider a massive scalar field coupled to gravity. In the field theoretic approach to quantum gravity (QG) we start with a massless second rank tensor field. This tensor field is then quantized in a covariant way in Minkowski space. This article deals with the adiabatic limit for graviton radiative corrections in a scattering process of two massive scalar particles. We compute the differential cross-section for bremsstrahlung processes in which one of the outgoing particles emites a graviton of low energy, a so called soft graviton. Since the emitted graviton will not be detected we have to integrate over all soft gravitons.
Cosmological perturbations in massive gravity with doubly coupled matter
Gümrükçüoğlu, A Emir; Mukohyama, Shinji
2014-01-01
We investigate the cosmological perturbations around FLRW solutions to non- linear massive gravity with a new effective coupling to matter proposed recently. Unlike the case with minimal matter coupling, all five degrees of freedom in the gravity sector propagate on generic self-accelerating FLRW backgrounds. We study the stability of the cosmological solutions and put constraints on the parameters of the theory by demanding the correct sign for the kinetic terms for scalar, vector and tensor perturbations.
Cosmological perturbations in massive gravity with doubly coupled matter
Gümrükçüoğlu, A. Emir; Heisenberg, Lavinia; Mukohyama, Shinji
2015-02-01
We investigate the cosmological perturbations around FLRW solutions to non- linear massive gravity with a new effective coupling to matter proposed recently. Unlike the case with minimal matter coupling, all five degrees of freedom in the gravity sector propagate on generic self-accelerating FLRW backgrounds. We study the stability of the cosmological solutions and put constraints on the parameters of the theory by demanding the correct sign for the kinetic terms for scalar, vector and tensor perturbations.
Quark-hadron phase transition in massive gravity
Atazadeh, K.
2016-11-01
We study the quark-hadron phase transition in the framework of massive gravity. We show that the modification of the FRW cosmological equations leads to the quark-hadron phase transition in the early massive Universe. Using numerical analysis, we consider that a phase transition based on the chiral symmetry breaking after the electroweak transition, occurred at approximately 10 μs after the Big Bang to convert a plasma of free quarks and gluons into hadrons.
Quark–hadron phase transition in massive gravity
Energy Technology Data Exchange (ETDEWEB)
Atazadeh, K., E-mail: atazadeh@azaruniv.ac.ir
2016-11-15
We study the quark–hadron phase transition in the framework of massive gravity. We show that the modification of the FRW cosmological equations leads to the quark–hadron phase transition in the early massive Universe. Using numerical analysis, we consider that a phase transition based on the chiral symmetry breaking after the electroweak transition, occurred at approximately 10 μs after the Big Bang to convert a plasma of free quarks and gluons into hadrons.
New Bi-Gravity from New Massive Garvity
Akhavan, A; Naseh, A; Nemati, A; Shirzad, A
2016-01-01
Using the action of three dimensional New Massive Gravity (NMG) we construct a new bi-gravity in three dimensions. This can be done by promoting the rank two auxiliary field appearing in the expression of NMG's action into a dynamical field. We show that small fluctuations around the AdS vacuum of the model are non-tachyonic and ghost free within certain range of the parameters of the model. We study central charges of the dual field theory and observe that in this range they are positive too. This suggests that the proposed model might be a consistent three dimensional bi-gravity.
Note About Hamiltonian Structure of Non-Linear Massive Gravity
Kluson, J
2011-01-01
We perform the Hamiltonian analysis of non-linear massive gravity action studied recently in arXiv:1106.3344 [hep-th]. We show that the Hamiltonian constraint is the second class constraint. As a result the theory possesses an odd number of the second class constraints and hence all non physical degrees of freedom cannot be eliminated.
Free energy of topologically massive gravity and flat space holography
Grumiller, Daniel
2015-01-01
We calculate the free energy from the on-shell action for topologically massive gravity with negative and vanishing cosmological constant, thereby providing a first principles derivation of the free energy of BTZ black holes and flat space cosmologies. We summarize related recent checks of flat space holography.
Superluminal Propagation and Acausality of Nonlinear Massive Gravity
Deser, S; Ong, Y C; Waldron, A
2013-01-01
Massive gravity is an old idea: trading geometry for mass. Much effort has been expended on establishing a healthy model, culminating in the current ghost-free version. We summarize here our recent findings -- that it is still untenable -- because it is locally acausal: CTC solutions can be constructed in a small neighborhood of any event.
Magnetic brane solutions in Gauss-Bonnet-Maxwell massive gravity
Hendi, Seyed Hossein; Eslam Panah, Behzad; Panahiyan, Shahram; Momennia, Mehrab
2017-09-01
Magnetic branes of Gauss-Bonnet-Maxwell theory in the context of massive gravity is studied in detail. Exact solutions are obtained and their interesting geometrical properties are investigated. It is argued that although these horizonless solutions are free of curvature singularity, they enjoy a cone-like geometry with a conic singularity. In order to investigate the effects of various parameters on the geometry of conic singularity, its corresponding deficit angle is studied. It will be shown that despite the effects of Gauss-Bonnet gravity on the solutions, deficit angle is free of Gauss-Bonnet parameter. On the other hand, the effects of massive gravity, cosmological constant and electrical charge on the deficit angle will be explored. Also, a brief discussion related to possible geometrical phase transition of these topological objects is given.
Self-accelerating Massive Gravity: Hidden Constraints and Characteristics
Motloch, Pavel; Motohashi, Hayato
2016-01-01
Self-accelerating backgrounds in massive gravity provide an arena to explore the Cauchy problem for derivatively coupled fields that obey complex constraints which reduce the phase space degrees of freedom. We present here an algorithm based on the Kronecker form of a matrix pencil that finds all hidden constraints, for example those associated with derivatives of the equations of motion, and characteristic curves for any 1+1 dimensional system of linear partial differential equations. With the Regge-Wheeler-Zerilli decomposition of metric perturbations into angular momentum and parity states, this technique applies to fully 3+1 dimensional perturbations of massive gravity around any isotropic self-accelerating background. Five spin modes of the massive graviton propagate once the constraints are imposed: two spin-2 modes with luminal characteristics present in the massless theory as well as two spin-1 modes and one spin-0 mode. Although the new modes all possess the same - typically spacelike - characteristi...
Vainshtein mechanism in massive gravity nonlinear sigma models
Aoki, Katsuki
2016-01-01
We study the stability of the Vainshtein screening solution of the massive/bi-gravity based on the massive nonlinear sigma model as the effective action inside the Vainshtein radius. The effective action is obtained by taking the $\\Lambda_2$ decoupling limit around a curved spacetime. First we derive a general consequence that any Ricci flat Vainshtein screening solution is unstable when we take into account the excitation of the scalar graviton only. This instability suggests that the nonlinear excitation of the scalar graviton is not sufficient to obtain a successful Vainshtein screening in massive/bi-gravity. Then to see the role of the excitation of the vector graviton, we study perturbations around the static and spherically symmetric solution obtained in bigravity explicitly. As a result, we find that linear excitations of the vector graviton cannot be helpful and the solution still suffers from a ghost and/or a gradient instability for any parameters of the theory for this background.
Holographical aspects of dyonic black holes: Massive gravity generalization
Hendi, S H; Panahiyan, S
2016-01-01
The content of this paper includes studying holographical and thermodynamical aspects of dyonic black holes in the presence of massive gravity. For the first part of paper, the thermodynamical properties of the bulk which includes black holes are studied. The main focus is on critical behavior. It will be shown that the existence of massive gravitons introduces remnant for temperature for evaporation of black holes, van der Waals phase transition for non-spherical black holes and etc. The consistency of different thermodynamical approaches toward critical behavior of the black holes is proven and the physical properties near to the region of thermal instability are given. Next part of paper studies holographical aspects of the boundary theory. Magnetization and susceptibility of the boundary are extracted and the conditions for having diamagnetic and paramagnetic behaviors are investigated. It will be shown that generalization to massive gravity results into the existences of diamagnetic/paramagnetic phases i...
Translation invariant time-dependent solutions to massive gravity
Energy Technology Data Exchange (ETDEWEB)
Mourad, J.; Steer, D.A., E-mail: mourad@apc.univ-paris7.fr, E-mail: steer@apc.univ-paris7.fr [AstroParticule and Cosmologie (UMR 7164 - APC, Univ Paris Diderot, CNRS/IN2P3, CEA/lrfu, Obs de Paris, Sorbonne Paris Cité, France), 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)
2013-12-01
Homogeneous time-dependent solutions of massive gravity generalise the plane wave solutions of the linearised Fierz-Pauli equations for a massive spin-two particle, as well as the Kasner solutions of General Relativity. We show that they also allow a clear counting of the degrees of freedom and represent a simplified framework to work out the constraints, the equations of motion and the initial value formulation. We work in the vielbein formulation of massive gravity, find the phase space resulting from the constraints and show that several disconnected sectors of solutions exist some of which are unstable. The initial values determine the sector to which a solution belongs. Classically, the theory is not pathological but quantum mechanically the theory may suffer from instabilities. The latter are not due to an extra ghost-like degree of freedom.
Translation invariant time-dependent solutions to massive gravity
Mourad, J
2013-01-01
Homogeneous time-dependent solutions of massive gravity generalise the plane wave solutions of the linearised Fierz-Pauli equations for a massive spin-two particle, as well as the Kasner solutions of General Relativity. We show that they also allow a clear counting of the degrees of freedom and represent a simplified framework to work out the constraints, the equations of motion and the initial value formulation. We work in the vielbein formulation of massive gravity, find the phase space resulting from the constraints and show that several disconnected sectors of solutions exist some of which are unstable. The initial values determine the sector to which a solution belongs. Classically, the theory is not pathological but quantum mechanically the theory may suffer from instabilities. The latter are not due to an extra ghost-like degree of freedom.
Dark Matter via Massive (bi-)Gravity
Blanchet, Luc
2015-01-01
In this work we investigate the existence of relativistic models for dark matter in the context of bimetric gravity, used here to reproduce the modified Newtonian dynamics (MOND) at galactic scales. For this purpose we consider two different species of dark matter particles that separately couple to the two metrics of bigravity. These two sectors are linked together \\textit{via} an internal $U(1)$ vector field, and some effective composite metric built out of the two metrics. Among possible models only certain class of kinetic and interaction terms are allowed without invoking ghost degrees of freedom. Along these lines we explore the number of allowed kinetic terms in the theory and point out the presence of ghosts in a previous model. Finally, we propose a promising class of ghost-free candidate theories that could provide the MOND phenomenology at galactic scales while reproducing the standard cold dark matter (CDM) model at cosmological scales.
Topologically massive gravity and Ricci-Cotton flow
Energy Technology Data Exchange (ETDEWEB)
Lashkari, Nima; Maloney, Alexander, E-mail: lashkari@physics.mcgill.ca, E-mail: maloney@physics.mcgill.ca [McGill Physics Department, 3600 rue University, Montreal, QC H3A 2T8 (Canada)
2011-05-21
We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.
Asymptotically flat black holes and gravitational waves in three-dimensional massive gravity
Troessaert, Cédric; Troncoso, Ricardo
2015-01-01
Different classes of exact solutions for the BHT massive gravity theory are constructed and analyzed. We focus in the special case of the purely quadratic Lagrangian, whose field equations are irreducibly of fourth order and are known to admit asymptotically locally flat black holes endowed with gravitational hair. The first class corresponds to a Kerr-Schild deformation of Minkowski spacetime along a covariantly constant null vector. As in the case of General Relativity, the field equations linearize so that the solution can be easily shown to be described by four arbitrary functions of a single null coordinate. These solutions can be regarded as a new sort of pp-waves. The second class is obtained from a deformation of the static asymptotically locally flat black hole, that goes along the spacelike (angular) Killing vector. Remarkably, although the deformation is not of Kerr-Schild type, the field equations also linearize, and hence the generic solution can be readily integrated. It is neither static nor sp...
One-loop divergences in massive gravity theory
Buchbinder, Ioseph L; Shapiro, Ilya L
2012-01-01
The one-loop divergences are calculated for the recently proposed ghost-free version of massive gravity, where the action depends on both metric and external tensor field f. The non-polynomial structure of the massive term is reduced to a more standard form by means of auxiliary tensor field, which is settled on-shell after quantum calculations are performed. As one should expect, the counterterms do not reproduce the form of the classical action. Moreover, the result has the form of the power series in f.
One-loop divergences in massive gravity theory
Buchbinder, I. L.; Pereira, D. D.; Shapiro, I. L.
2012-05-01
The one-loop divergences are calculated for the recently proposed ghost-free massive gravity model, where the action depends on both metric and external tensor field f. The non-polynomial structure of the massive term is reduced to a more standard form by means of auxiliary tensor field, which is settled on-shell after quantum calculations are performed. As one should expect, the counter-terms do not reproduce the form of the classical action. Moreover, the result has the form of the power series in f.
Giant black hole ringings induced by massive gravity
Decanini, Yves; Hadj, Mohamed Ould El
2014-01-01
A distorted black hole radiates gravitational waves in order to settle down in one of the geometries permitted by the no-hair theorem. During that relaxation phase, a characteristic damped ringing is generated. It can be theoretically constructed from the black hole quasinormal frequencies (which govern its oscillating behavior and its decay) and from the associated excitation factors (which determine intrinsically its amplitude) by carefully taking into account the source of the distortion. Here, by considering the Schwarzschild black hole in the framework of massive gravity, we show that the excitation factors have an unexpected strong resonant behavior leading to giant ringings which are, moreover, slowly decaying. Such extraordinary black hole ringings could be observed by the next generations of gravitational wave detectors and allow us to test the various massive gravity theories or their absence could be used to impose strong constraints on the graviton mass.
No hair theorem in quasi-dilaton massive gravity
Energy Technology Data Exchange (ETDEWEB)
Wu, De-Jun, E-mail: wudejun10@mails.ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhou, Shuang-Yong, E-mail: sxz353@case.edu [Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106 (United States)
2016-06-10
We investigate the static, spherically symmetric black hole solutions in the quasi-dilaton model and its generalizations, which are scalar extended dRGT massive gravity with a shift symmetry. We show that, unlike generic scalar extended massive gravity models, these theories do not admit static, spherically symmetric black hole solutions until the theory parameters in the dRGT potential are fine-tuned. When fine-tuned, the geometry of the static, spherically symmetric black hole is necessarily that of general relativity and the quasi-dilaton field is constant across the spacetime. The fine-tuning and the no hair theorem apply to black holes with flat, anti-de Sitter or de Sitter asymptotics.
Cosmology in massive gravity with effective composite metric
Heisenberg, Lavinia
2016-01-01
This paper is dedicated to scrutinizing the cosmology in massive gravity. A matter field of the dark sector is coupled to an effective composite metric while a standard matter field couples to the dynamical metric in the usual way. For this purpose, we study the dynamical system of cosmological solutions by using phase analysis, which provides an overview of the class of cosmological solutions in this setup. This also permits us to study the critical points of the cosmological equations together with their stability. We show the presence of stable attractor de Sitter critical points relevant to the late-time cosmic acceleration. Furthermore, we study the tensor, vector and scalar perturbations in the presence of standard matter fields and obtain the conditions for the absence of ghost and gradient instabilities. Hence, massive gravity in the presence of the effective composite metric can accommodate interesting dark energy phenomenology, that can be observationally distinguished from the standard model accord...
Spherically Symmetric Solutions in Ghost-Free Massive Gravity
Comelli, D; Nesti, F; Pilo, L
2011-01-01
Recently, a class of theories of massive gravity has been shown to be ghost-free. We study the spherically symmetric solutions in the bigravity formulation of such theories. In general, the solutions admit both a Lorentz invariant and a Lorentz breaking asymptotically flat behaviour and also fall in two branches. In the first branch, all solutions can be found analitycally and are Schwarzschild-like, with no modification as is found for other classes of theories. In the second branch, exact solutions are hard to find, and relying on perturbation theory, Yukawa-like modifications of the static potential are found. The general structure of the solutions suggests that the bigravity formulation of massive gravity is crucial and more than a tool.
Homogeneous solutions of minimal massive 3D gravity
Charyyev, Jumageldi; Deger, Nihat Sadik
2017-07-01
In this paper, we systematically construct simply transitive homogeneous spacetime solutions of the three-dimensional minimal massive gravity (MMG) model. In addition to those that have analogs in topologically massive gravity, such as warped AdS and p p waves, there are several solutions genuine to MMG. Among them, there is a stationary Lifshitz metric with the dynamical exponent z =-1 and an anisotropic Lifshitz solution where all coordinates scale differently. Moreover, we identify a homogeneous Kundt-type solution at the chiral point of the theory. We also show that in a particular limit of the physical parameters in which the Cotton tensor drops out from the MMG field equation, homogeneous solutions exist only at the merger point in the parameter space if they are not conformally flat.
No hair theorem in quasi-dilaton massive gravity
Wu, De-Jun
2016-01-01
We investigate the static, spherically symmetric black hole solutions in the quasi-dilaton model and its generalizations, which are scalar extended dRGT massive gravity with a shift symmetry. We show that, unlike generic scalar extended massive gravity models, these theories do not admit static, spherically symmetric black hole solutions until the theory parameters in the dRGT potential is fine-tuned. When fine-tuned, the geometry of the static, spherically symmetric black hole is necessarily that of general relativity and the quasi-dilaton field is constant across the spacetime. The fine-tuning and the no hair theorem apply to black holes with flat, anti-de Sitter or de Sitter asymptotics.
No hair theorem in quasi-dilaton massive gravity
Wu, De-Jun; Zhou, Shuang-Yong
2016-06-01
We investigate the static, spherically symmetric black hole solutions in the quasi-dilaton model and its generalizations, which are scalar extended dRGT massive gravity with a shift symmetry. We show that, unlike generic scalar extended massive gravity models, these theories do not admit static, spherically symmetric black hole solutions until the theory parameters in the dRGT potential are fine-tuned. When fine-tuned, the geometry of the static, spherically symmetric black hole is necessarily that of general relativity and the quasi-dilaton field is constant across the spacetime. The fine-tuning and the no hair theorem apply to black holes with flat, anti-de Sitter or de Sitter asymptotics.
Anisotropic Friedmann-Robertson-Walker universe from nonlinear massive gravity
Gumrukcuoglu, A Emir; Mukohyama, Shinji
2012-01-01
In the scope of the nonlinear massive gravity, we study fixed points of evolution equations for a Bianchi type--I universe. We find a new attractor solution with non-vanishing anisotropy, on which the physical metric is isotropic but the Stuckelberg configuration is anisotropic. As a result, at the background level, the solution describes a homogeneous and isotropic universe, while a statistical anisotropy is expected from perturbations, suppressed by smallness of the graviton mass.
Massive and modified gravity as self-gravitating media
Ballesteros, Guillermo; Pilo, Luigi
2016-01-01
We study the effective field theory that describes the low-energy physics of self-gravitating media. The field content consists of four derivatively coupled scalar fields that can be identified with the internal comoving coordinates of the medium. Imposing SO(3) internal spatial invariance, the theory describes supersolids. Stronger symmetry requirements lead to superfluids, solids and perfect fluids, at lowest order in derivatives. In the unitary gauge, massive gravity emerges, being thus the result of a continuous medium propagating in spacetime. Our results can be used to explore systematically the effects and signatures of modifying gravity consistently at large distances. The dark sector is then described as a self-gravitating medium with dynamical and thermodynamic properties dictated by internal symmetries. These results indicate that the divide between dark energy and modified gravity, at large distance scales, is simply a gauge choice.
Completing Lorentz violating massive gravity at high energies
Blas, Diego
2015-01-01
Theories with massive gravitons are interesting for a variety of physical applications, ranging from cosmological phenomena to holographic modeling of condensed matter systems. To date, they have been formulated as effective field theories with a cutoff proportional to a positive power of the graviton mass m_g and much smaller than that of the massless theory (M_P ~ 10^19 GeV in the case of general relativity). In this paper we present an ultraviolet completion for massive gravity valid up to a high energy scale independent of the graviton mass. The construction is based on the existence of a preferred time foliation combined with spontaneous condensation of vector fields. The perturbations of these fields are massive and below their mass the theory reduces to a model of Lorentz violating massive gravity. The latter theory possesses instantaneous modes whose consistent quantization we discuss in detail. We briefly study some modifications to gravitational phenomenology at low-energies. The homogeneous cosmolo...
Zwei-Dreibein Gravity : A Two-Frame-Field Model of 3D Massive Gravity
Bergshoeff, Eric A.; de Haan, Sjoerd; Hohm, Olaf; Merbis, Wout; Townsend, Paul K.
2013-01-01
We present a generally covariant and parity-invariant two-frame field ("zwei-dreibein") action for gravity in three space-time dimensions that propagates two massive spin-2 modes, unitarily, and we use Hamiltonian methods to confirm the absence of unphysical degrees of freedom. We show how
Zwei-Dreibein Gravity : A Two-Frame-Field Model of 3D Massive Gravity
Bergshoeff, Eric A.; de Haan, Sjoerd; Hohm, Olaf; Merbis, Wout; Townsend, Paul K.
2013-01-01
We present a generally covariant and parity-invariant two-frame field ("zwei-dreibein") action for gravity in three space-time dimensions that propagates two massive spin-2 modes, unitarily, and we use Hamiltonian methods to confirm the absence of unphysical degrees of freedom. We show how zwei-drei
Self-accelerating massive gravity: Hidden constraints and characteristics
Motloch, Pavel; Hu, Wayne; Motohashi, Hayato
2016-05-01
Self-accelerating backgrounds in massive gravity provide an arena to explore the Cauchy problem for derivatively coupled fields that obey complex constraints which reduce the phase space degrees of freedom. We present here an algorithm based on the Kronecker form of a matrix pencil that finds all hidden constraints, for example those associated with derivatives of the equations of motion, and characteristic curves for any 1 +1 dimensional system of linear partial differential equations. With the Regge-Wheeler-Zerilli decomposition of metric perturbations into angular momentum and parity states, this technique applies to fully 3 +1 dimensional perturbations of massive gravity around any spherically symmetric self-accelerating background. Five spin modes of the massive graviton propagate once the constraints are imposed: two spin-2 modes with luminal characteristics present in the massless theory as well as two spin-1 modes and one spin-0 mode. Although the new modes all possess the same—typically spacelike—characteristic curves, the spin-1 modes are parabolic while the spin-0 modes are hyperbolic. The joint system, which remains coupled by nonderivative terms, cannot be solved as a simple Cauchy problem from a single noncharacteristic surface. We also illustrate the generality of the algorithm with other cases where derivative constraints reduce the number of propagating degrees of freedom or order of the equations.
Reply to "Comment on `Quantum massive conformal gravity' by F. F. Faria"
Faria, F. F.
2017-01-01
Recently in (Eur Phys J C 76:341, 2016), Myung has suggested that the renormalizability of massive conformal gravity is meaningless unless the massive ghost states of the theory are stable. Here we show that massive conformal gravity can be renormalizable having unstable ghost states.
Horizon Fluffs: In the Context of Generalized Minimal Massive Gravity
Setare, M R
2016-01-01
We consider a metric which describes Ba$\\tilde{\\text{n}}$ados geometries and show that the considered metric is a solution of generalized minimal massive gravity (GMMG) model. We consider the Killing vector field which preserves the form of considered metric. Using the off-shell quasi-local approach we obtain the asymptotic conserved charges of given solution. Similar to the Einstein gravity in the presence of negative cosmological constant, for the GMMG model also, we show that the algebra among the asymptotic conserved charges is isomorphic to two copies of the Virasoro algebra. Eventually, we find relation between the algebra of the near horizon and the asymptotic conserved charges. This relation show that the main part of the horizon fluffs proposal of Refs.\\cite{140,14} appear for generic black holes in the class of Ba$\\tilde{\\text{n}}$ados geometries in the context of GMMG model.
Geometric Massive Gravity in Multi-Connection Framework
Khosravi, Nima
2013-01-01
What is the right way to interpret a massive graviton? We generalize the kinematical framework of general relativity to multiple connections. The average of the connections is itself a connection and plays the role of the canonical connection in standard General Relativity. At the level of dynamics, the simplest choice of the Einstein-Hilbert action is indistinguishable from the single-connection case. However, inspired by Weyl geometry, we show how one can construct massive gravity to all orders in perturbation theory compatible with the de Rham-Gabadadze-Tolley ghost-free model. We conclude that the mass of the graviton can be interpreted as a geometrical property of spacetime arising from two connections. Furthermore in the multi-connection framework there is no ambiguity in the definition of physical metric and consequently coupling to matter.
First law of entanglement entropy in topologically massive gravity
Cheng, Long; Hung, Ling-Yan; Liu, Si-Nong; Zhou, Hong-Zhe
2016-09-01
In this paper we explore the validity of the first law of entanglement entropy in the context of topologically massive gravity (TMG). We find that the variation of the holographic entanglement entropy under perturbation from the pure anti-de Sitter background satisfies the first law upon imposing the bulk equations of motion in a given time slice, despite the appearance of instabilities in the bulk for generic gravitational Chern-Simons coupling μ . The Noether-Wald entropy is different from the holographic entanglement entropy in a general boosted frame. However, this discrepancy does not affect the entanglement first law.
On dRGT massive gravity with degenerate reference metrics
CAO, LI-MING; Peng, Yuxuan; Zhang, Yun-Long(State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, China)
2015-01-01
In dRGT massive gravity, to get the equations of motion, the square root tensor is assumed to be invertible in the variation of the action. However, this condition can not be fulfilled when the reference metric is degenerate. This implies that the resulting equations of motion might be different from the case where the reference metric has full rank. In this paper, by generalizing the Moore-Penrose inverse to the symmetric tensor on Lorentz manifolds, we get the equations of motion of the the...
Massive gravity: nonlinear instability of the homogeneous and isotropic universe
De Felice, Antonio; Mukohyama, Shinji
2012-01-01
We study the propagating modes for nonlinear massive gravity on a Bianchi type--I manifold. We analyze their kinetic terms and dispersion relations as the background manifold approaches the homogeneous and isotropic limit. We show that in this limit, at least one ghost always exists and that its frequency tends to vanish for large scales, meaning that it cannot be integrated out from the low energy effective theory. Since this ghost mode can be considered as a leading nonlinear perturbation around a homogeneous and isotropic background, we conclude that the universe in this theory must be either inhomogeneous or anisotropic.
Thermodynamics and Geometrothermodynamics of Charged black holes in Massive Gravity
Suresh, Jishnu; Prabhakar, Geethu; Kuriakose, V C
2016-01-01
The objective of this paper is to study the thermodynamics and thermodynamic geometry of charged de-Sitter and charged anti de-Sitter black hole solutions in massive gravity. In this study, the presence of a negative cosmological constant is identified as a thermodynamic variable, the pressure. By incorporating this idea, we study the effect of curvature parameter as well as the mass of graviton in the thermodynamics of the black hole system. We further extend our studies to different topology of the space time and its effects on phase transition and thermodynamics. In addition, the phase transition structure of the black hole and its interactions are reproduced using geometrothermodynamics.
Translation invariant time-dependent massive gravity: Hamiltonian analysis
Energy Technology Data Exchange (ETDEWEB)
Mourad, Jihad; Steer, Danièle A. [Laboratoire APC -- Astroparticule et Cosmologie, Université Paris Diderot, 75013 Paris (France); Noui, Karim, E-mail: mourad@apc.univ-paris7.fr, E-mail: karim.noui@lmpt.univ-tours.fr, E-mail: steer@apc.univ-paris7.fr [Laboratoire de Mathématiques et Physique Théorique, Université François Rabelais, Parc de Grandmont, 37200 Tours (France)
2014-09-01
The canonical structure of the massive gravity in the first order moving frame formalism is studied. We work in the simplified context of translation invariant fields, with mass terms given by general non-derivative interactions, invariant under the diagonal Lorentz group, depending on the moving frame as well as a fixed reference frame. We prove that the only mass terms which give 5 propagating degrees of freedom are the dRGT mass terms, namely those which are linear in the lapse. We also complete the Hamiltonian analysis with the dynamical evolution of the system.
Translation invariant time-dependent massive gravity: Hamiltonian analysis
Mourad, Jihad; Steer, Danièle A
2014-01-01
The canonical structure of the massive gravity in the first order moving frame formalism is studied. We work in the simplified context of translation invariant fields, with mass terms given by general non-derivative interactions, invariant under the diagonal Lorentz group, depending on the moving frame as well as a fixed reference frame. We prove that the only mass terms which give 5 propagating degrees of freedom are the dRGT mass terms, namely those which are linear in the lapse. We also complete the Hamiltonian analysis with the dynamical evolution of the system.
"Non-Relativistic" Behavior of Massive Gravity Sources
Deser, S
2014-01-01
We exhibit novel effects (absent in GR) of sources in massive gravity. First, we show that removing its ghost mode forces a field-current identity: The metric's trace is locally proportional to that of its stress tensor; a point source implies a metric singularity enhanced by the square of the graviton's range. Second, exterior solutions acquire spatial stress hair--their metric components depend on the interior T_ij(r). Also, in contrast to naive expectations, the Newtonian potential of a source is now determined by both its interior's spatial stress and mass. Our explicit results are obtained at linear, Fierz-Pauli, level, but ought to persist nonlinearly.
Mass-varying massive gravity with k-essence
Energy Technology Data Exchange (ETDEWEB)
Tannukij, Lunchakorn [Mahidol University, Department of Physics, Faculty of Science, Bangkok (Thailand); Wongjun, Pitayuth [Naresuan University, The Institute for Fundamental Study, Phitsanulok (Thailand); Thailand Center of Excellence in Physics, Ministry of Education, Bangkok (Thailand)
2016-01-15
For a large class of mass-varying massive-gravity models, the graviton mass cannot provide the late-time cosmic expansion of the universe due to its vanishing at late time. In this work, we propose a new class of mass-varying massive gravity models, in which the graviton mass varies according to a kinetic term of a k-essence field. By using a more general form of the fiducial metric, we found a solution such that a non-vanishing graviton mass can drive the accelerated expansion of the universe at late time. We also perform dynamical analyses of such a model and find that without introducing the k-essence Lagrangian, the graviton mass can be responsible for both dark contents of the universe, namely dark energy, which drives the accelerated expansion of the universe, and non-relativistic matter, which plays the role of dark matter. Moreover, by including the k-essence Lagrangian, we find that it is possible to alleviate the so-called cosmic coincidence problem. (orig.)
Cosmology in massive gravity with effective composite metric
Heisenberg, Lavinia; Refregier, Alexandre
2016-09-01
This paper is dedicated to scrutinizing the cosmology in massive gravity. A matter field of the dark sector is coupled to an effective composite metric while a standard matter field couples to the dynamical metric in the usual way. For this purpose, we study the dynamical system of cosmological solutions by using phase analysis, which provides an overview of the class of cosmological solutions in this setup. This also permits us to study the critical points of the cosmological equations together with their stability. We show the presence of stable attractor de Sitter critical points relevant to the late-time cosmic acceleration. Furthermore, we study the tensor, vector and scalar perturbations in the presence of standard matter fields and obtain the conditions for the absence of ghost and gradient instabilities. Hence, massive gravity in the presence of the effective composite metric can accommodate interesting dark energy phenomenology, that can be observationally distinguished from the standard model according to the expansion history and cosmic growth.
Conserved Charges of Minimal Massive Gravity Coupled to Scalar Field
Setare, M R
2016-01-01
Recently, the theory of Topologically massive gravity non-minimally coupled to a scalar field has been proposed which comes from Lorentz-Chern-Simons theory \\cite{1}. That theory is a torsion free one. We extend that theory by adding an extra term which makes torsion to be non-zero. The extended theory can be regarded as an extension of Minimal massive gravity such that it is non-minimally coupled to a scalar field. We obtain equations of motion of extended theory such that they are expressed in terms of usual torsion free spin-connection. We show that BTZ spacetime is a solution of this theory when scalar field is constant. We define quasi-local conserved charge by the concept of generalized off-shell ADT current which both are conserved for any asymptotically Killing vector field as well as a Killing vector field which is admitted by spacetime everywhere. Also we find general formula for entropy of stationary black hole solution in the context of considered theory. We apply the obtained formulas on BTZ blac...
Stable and unstable cosmological models in bimetric massive gravity
Könnig, Frank; Amendola, Luca; Motta, Mariele; Solomon, Adam R
2014-01-01
Nonlinear, ghost-free massive gravity has two tensor fields; when both are dynamical, the mass of the graviton can lead to cosmic acceleration that agrees with background data, even in the absence of a cosmological constant. Here the question of the stability of linear perturbations in this theory is examined. Instabilities are presented for several classes of models, and simple criteria for the cosmological stability of massive bigravity are derived. In this way, we identify a particular self-accelerating bigravity model, infinite-branch bigravity (IBB), which exhibits both viable background evolution and stable linear perturbations. We discuss the modified gravity parameters for IBB, which do not reduce to the standard $\\Lambda$CDM result at early times, and compute the combined likelihood from measured growth data and type Ia supernovae. IBB predicts a present matter density $\\Omega_{m0}=0.18$ and an equation of state $w(z)=-0.79+0.21z/(1+z)$. The growth rate of structure is well-approximated at late times...
Extended DBI massive gravity with generalized fiducial metric
Energy Technology Data Exchange (ETDEWEB)
Chullaphan, Tossaporn [The Institute for Fundamental Study, Naresuan University,Phitsanulok 65000 (Thailand); Department of Physics, Faculty of Science, Udon Thani Rajabhat University,Udon Thani 41000 (Thailand); Tannukij, Lunchakorn [Department of Physics, Faculty of Science, Mahidol University,Bangkok 10400 (Thailand); Wongjun, Pitayuth [The Institute for Fundamental Study, Naresuan University,Phitsanulok 65000 (Thailand); Thailand Center of Excellence in Physics, Ministry of Education,Bangkok 10400 (Thailand)
2015-06-05
We consider an extended model of DBI massive gravity by generalizing the fiducial metric to be an induced metric on the brane corresponding to a domain wall moving in five-dimensional Schwarzschild-Anti-de Sitter spacetime. The model admits all solutions of FLRW metric including flat, closed and open geometries while the original one does not. The background solutions can be divided into two branches namely self-accelerating branch and normal branch. For the self-accelerating branch, the graviton mass plays the role of cosmological constant to drive the late-time acceleration of the universe. It is found that the number degrees of freedom of gravitational sector is not correct similar to the original DBI massive gravity. There are only two propagating degrees of freedom from tensor modes. For normal branch, we restrict our attention to a particular class of the solutions which provides an accelerated expansion of the universe. It is found that the number of degrees of freedom in the model is correct. However, at least one of them is ghost degree of freedom which always present at small scale implying that the theory is not stable.
Bardeen variables and hidden gauge symmetries in linearized massive gravity
Jaccard, Maud; Mitsou, Ermis
2012-01-01
We give a detailed discussion of the use of the (3+1) decomposition and of Bardeen's variables in massive gravity linearized over a Minkowski as well as over a de Sitter background. In Minkowski space the Bardeen "potential" \\Phi, that in the massless case is a non-radiative degree of freedom, becomes radiative and describes the helicity-0 component of the massive graviton. Its dynamics is governed by a simple Klein-Gordon action, supplemented by a term (\\Box \\Phi)^2 if we do not make the Fierz-Pauli tuning of the mass term. In de Sitter the identification of the variable that describes the radiative degree of freedom in the scalar sector is more subtle, and even involves expressions non-local in time. The use of this new variable provides a simple and transparent derivation of the Higuchi bound and of the disappearance of the scalar degree of freedom at a special value of $m_g^2/H^2$. The use of this formalism also allows us to uncover the existence of a hidden gauge symmetry of the massive theory, that beco...
Cosmological bounds on open FLRW solutions of massive gravity
Pereira, S H; S., A Pinho S; Jesus, J F
2015-01-01
In this work we have analysed some cosmological bounds concerning an open FLRW solution of massive gravity. The constraints with recent observational $H(z)$ data were found and the best fit values for the cosmological parameters are in agreement with the $\\Lambda$CDM model, and also point to a nearly open spatial curvature, as expected from the model. The graviton mass dependence with the constant parameters $\\alpha_3$ and $\\alpha_4$, related to the additional lagrangians terms of the model, are also analysed, and we have obtained a strong dependence with such parameters, although the condition $m_g\\simeq H_0^{-1}$ seems dominant for a long range of the parameters $\\alpha_3$ and $\\alpha_4$. The limit $\\alpha_2 \\to 0$ forbid one of the branches of accelerated solution, which indicates the necessity of the corresponding lagrangian term.
Matter coupling in partially constrained vielbein formulation of massive gravity
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Felice, Antonio De [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Gümrükçüoğlu, A. Emir [School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Heisenberg, Lavinia [Institute for Theoretical Studies, ETH Zurich,Clausiusstrasse 47, 8092 Zurich (Switzerland); Mukohyama, Shinji [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Kavli Institute for the Physics and Mathematics of the Universe,Todai Institutes for Advanced Study, University of Tokyo (WPI),5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)
2016-01-04
We consider a linear effective vielbein matter coupling without introducing the Boulware-Deser ghost in ghost-free massive gravity. This is achieved in the partially constrained vielbein formulation. We first introduce the formalism and prove the absence of ghost at all scales. As next we investigate the cosmological application of this coupling in this new formulation. We show that even if the background evolution accords with the metric formulation, the perturbations display important different features in the partially constrained vielbein formulation. We study the cosmological perturbations of the two branches of solutions separately. The tensor perturbations coincide with those in the metric formulation. Concerning the vector and scalar perturbations, the requirement of absence of ghost and gradient instabilities yields slightly different allowed parameter space.
Chronology Protection in Galileon Models and Massive Gravity
Burrage, Clare; Heisenberg, Lavinia; Tolley, Andrew J
2011-01-01
Galileon models are a class of effective field theories that have recently received much attention. They arise in the decoupling limit of theories of massive gravity, and in some cases they have been treated in their own right as scalar field theories with a specific nonlinearly realized global symmetry (Galilean transformation). It is well known that in the presence of a source, these Galileon theories admit superluminal propagating solutions, implying that as quantum field theories they must admit a different notion of causality than standard local Lorentz invariant theories. We show that in these theories it is easy to construct closed timelike curves (CTCs) within the {\\it naive} regime of validity of the effective field theory. However, on closer inspection we see that the CTCs could never arise since the Galileon inevitably becomes infinitely strongly coupled at the onset of the formation of a CTC. This implies an infinite amount of backreaction, first on the background for the Galileon field, signaling...
Matter coupling in partially constrained vielbein formulation of massive gravity
De Felice, Antonio; Heisenberg, Lavinia; Mukohyama, Shinji
2015-01-01
We consider a consistent linear effective vielbein matter coupling without introducing the Boulware-Deser ghost in ghost-free massive gravity. This is achieved in the partially constrained vielbein formulation. We first introduce the formalism and prove the absence of ghost at all scales. As next we investigate the cosmological application of this coupling in this new formulation. We show that even if the background evolution accords with the metric formulation, the perturbations display important different features in the partially constrained vielbein formulation. We study the cosmological perturbations of the two branches of solutions separately. The tensor perturbations coincide with those in the metric formulation. Concerning the vector and scalar perturbations, the requirement of absence of ghost and gradient instabilities yields slightly different allowed parameter space.
Ghosts & Matter Couplings in Massive (bi-&multi-)Gravity
de Rham, Claudia; Ribeiro, Raquel H
2014-01-01
Recently, several works have investigated the coupling to matter in ghost-free massive (bi-&multi-)gravity and a new effective coupling to matter has been proposed. In this note we clarify some confusion on the existence and the implications of a ghost above the strong coupling scale. We confirm that the standard constraint which is otherwise typically present in this type of theories disappears on generic backgrounds as soon as this new coupling is considered. This implies the re-emergence of the Boulware-Deser ghost. Nevertheless the absence of ghost in the decoupling limit implies that the cut-off scale (if identified with the scale at which the ghost enters) is higher than the strong coupling scale. Therefore there is a valid interesting region of applicability for these couplings at scales below the cut-off.
Matter coupling in partially constrained vielbein formulation of massive gravity
De Felice, Antonio; Gümrükçüoğlu, A. Emir; Heisenberg, Lavinia; Mukohyama, Shinji
2016-01-01
We consider a linear effective vielbein matter coupling without introducing the Boulware-Deser ghost in ghost-free massive gravity. This is achieved in the partially constrained vielbein formulation. We first introduce the formalism and prove the absence of ghost at all scales. As next we investigate the cosmological application of this coupling in this new formulation. We show that even if the background evolution accords with the metric formulation, the perturbations display important different features in the partially constrained vielbein formulation. We study the cosmological perturbations of the two branches of solutions separately. The tensor perturbations coincide with those in the metric formulation. Concerning the vector and scalar perturbations, the requirement of absence of ghost and gradient instabilities yields slightly different allowed parameter space.
Charged Black Hole Solutions in Gauss-Bonnet-Massive Gravity
Hendi, S H; Panah, B Eslam
2015-01-01
Motivated by high interest in the close relation between string theory and black hole solutions, in this paper, we take into account the Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity. We examine the possibility of black hole in this regard, and discuss the types of horizons. Next, we calculate conserved and thermodynamic quantities and check the validity of the first law of thermodynamics. In addition, we investigate the stability of these black holes in context of canonical ensemble. We show that number, type and place of phase transitions points may be significantly affected by the different parameters. Next, by considering cosmological constant as thermodynamical pressure, we will extend phase space and calculate critical values. Then, we construct thermodynamical spacetime by considering mass as thermodynamical potential. We study geometrical thermodynamics of these black holes in context of heat capacity and extended phase space. We show that studying heat capacity, geometrical therm...
Hawking–Page phase transition in new massive gravity
Directory of Open Access Journals (Sweden)
Shao-Jun Zhang
2015-07-01
Full Text Available We consider Hawking–Page phase transition between the BTZ black hole with M≥0 and the thermal soliton with M=−1 in new massive gravity. By comparing the on-shell free energies, we can see that there exists a critical temperature. The thermal soliton is more probable than the black hole below the critical temperature while the black hole is more probable than the thermal soliton above the critical temperature. By consistently constructing the off-shell free energies taking into account the conical singularity, we show that there exist infinite non-equilibrium states connecting the BTZ black hole and the thermal soliton, so that they provide a picture of continuous evolution of the phase transition.
Phase transition of holographic entanglement entropy in massive gravity
Energy Technology Data Exchange (ETDEWEB)
Zeng, Xiao-Xiong, E-mail: xxzeng@itp.ac.cn [School of Material Science and Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Hongbao, E-mail: hzhang@vub.ac.be [Department of Physics, Beijing Normal University, Beijing 100875 (China); Theoretische Natuurkunde, Vrije Universiteit Brussel, and The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Li, Li-Fang, E-mail: lilf@itp.ac.cn [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China)
2016-05-10
The phase structure of holographic entanglement entropy is studied in massive gravity for the quantum systems with finite and infinite volumes, which in the bulk is dual to calculating the minimal surface area for a black hole and black brane respectively. In the entanglement entropy–temperature plane, we find for both the black hole and black brane there is a Van der Waals-like phase transition as the case in thermal entropy–temperature plane. That is, there is a first order phase transition for the small charge and a second order phase transition at the critical charge. For the first order phase transition, the equal area law is checked and for the second order phase transition, the critical exponent of the heat capacity is obtained. All the results show that the phase structure of holographic entanglement entropy is the same as that of thermal entropy regardless of the volume of the spacetime on the boundary.
Pre-heating in the framework of massive gravity
Directory of Open Access Journals (Sweden)
Debaprasad Maity
2016-09-01
Full Text Available In this paper we propose a mechanism of natural pre-heating of our universe by introducing an inflaton field dependent mass term for the gravitational wave for a specific class of massive gravity theory. For any single field inflationary model, the inflaton must go through the oscillatory phase after the end of inflation. As has recently been pointed out, if the gravitational fluctuation has inflaton dependent mass term, there will be a resonant amplification of the amplitude of the gravitational wave during the oscillatory phase of inflaton. Because of this large enhancement of the amplitude of the gravitational wave due to parametric resonance, we show that universe can naturally go through the pre-reheated phase with minimally coupled matter field. Therefore, during the reheating phase, there is no need to introduce any arbitrary coupling between the matter field and the inflaton.
Nonlinear stability of cosmological solutions in massive gravity
De Felice, Antonio; Lin, Chunshan; Mukohyama, Shinji
2013-01-01
We investigate nonlinear stability of two classes of cosmological solutions in massive gravity: isotropic Friedmann-Lemaitre-Robertson-Walker (FLRW) solutions and anisotropic FLRW solutions. For this purpose we construct the linear cosmological perturbation theory around axisymmetric Bianchi type--I backgrounds. We then expand the background around the two classes of solutions, which are fixed points of the background evolution equation, and analyze linear perturbations on top of it. This provides a consistent truncation of nonlinear perturbations around these fixed point solutions and allows us to analyze nonlinear stability in a simple way. In particular, it is shown that isotropic FLRW solutions exhibit nonlinear ghost instability. On the other hand, anisotropic FLRW solutions are shown to be ghost-free for a range of parameters and initial conditions.
Role of matter in extended quasidilaton massive gravity
Gumrukcuoglu, A Emir; Mukohyama, Shinji
2016-01-01
The extended quasidilaton theory is one of the simplest Lorentz-invariant massive gravity theories which can accommodate a stable self-accelerating vacuum solution. In this paper we revisit this theory and study the effect of matter fields. For a matter sector that couples minimally to the physical metric, we find hints of a Jeans type instability in the IR. In the analogue k-essence field set-up, this instability manifests itself as an IR ghost for the scalar field perturbation, but this can be interpreted as a classical instability that becomes relevant below some momentum scale in terms of matter density perturbations. We also consider the effect of the background evolution influenced by matter on the stability of the gravity sector perturbations. In particular, we address the previous claims of ghost instability in the IR around the late time attractor. We show that, although the matter-induced modification of the evolution potentially brings tension to the stability conditions, one goes beyond the regime...
Witten-Nester energy in topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Sezgin, Ergin [George and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Tanii, Yoshiaki, E-mail: sezgin@physics.tamu.ed, E-mail: tanii@phy.saitama-u.ac.j [Division of Material Science, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570 (Japan)
2009-12-07
We formulate topologically massive supergravity with a cosmological constant in the first-order formalism and construct the Noether supercurrent and superpotential associated with its local supersymmetry. Using these results, we construct in ordinary topologically massive gravity the Witten-Nester integral for conserved charges containing spinors which satisfy a generalized version of the Witten equation on the initial value surface. We show that the Witten-Nester charge, represented as an integral over the boundary of the initial value surface, produces the Abbott-Deser-Tekin energy for asymptotically anti-de Sitter spacetimes. We consider all values of the Chern-Simons coupling constant, including the critical value known as the chiral point, and study the cases of standard Brown-Henneaux boundary conditions, as well as their weaker version that allows a slower fall-off. Studying the Witten-Nester energy as a bulk integral over the initial value surface instead, we find a bound on the energy, and through it the sufficient condition for the positivity of the energy. In particular, we find that spacetimes of Petrov type N that admit globally well-defined solutions of the generalized Witten equation have positive energy.
Translation invariant time-dependent solutions to massive gravity II
Energy Technology Data Exchange (ETDEWEB)
Mourad, J.; Steer, D.A., E-mail: mourad@apc.univ-paris7.fr, E-mail: steer@apc.univ-paris7.fr [AstroParticule and Cosmologie, UMR 7164-CNRS, Université Denis Diderot-Paris 7, CEA, Observatoire de Paris, F-75205 Paris Cedex 13 (France)
2014-06-01
This paper is a sequel to JCAP 12 (2013) 004 and is also devoted to translation-invariant solutions of ghost-free massive gravity in its moving frame formulation. Here we consider a mass term which is linear in the vielbein (corresponding to a β{sub 3} term in the 4D metric formulation) in addition to the cosmological constant. We determine explicitly the constraints, and from the initial value formulation show that the time-dependent solutions can have singularities at a finite time. Although the constraints give, as in the β{sub 1} case, the correct number of degrees of freedom for a massive spin two field, we show that the lapse function can change sign at a finite time causing a singular time evolution. This is very different to the β{sub 1} case where time evolution is always well defined. We conclude that the β{sub 3} mass term can be pathological and should be treated with care.
Translation invariant time-dependent solutions to massive gravity II
Mourad, J
2014-01-01
This paper is a sequel to arXiv:1310.6560 [hep-th] and is also devoted to translation-invariant solutions of ghost-free massive gravity in its moving frame formulation. Here we consider a mass term which is linear in the vielbein (corresponding to a $\\beta_3$ term in the 4D metric formulation) in addition to the cosmological constant. We determine explicitly the constraints, and from the initial value formulation show that the time-dependent solutions can have singularities at a finite time. Although the constraints give, as in the $\\beta_1$ case, the correct number of degrees of freedom for a massive spin two field, we show that the lapse function can change sign at a finite time causing a singular time evolution. This is very different to the $\\beta_1$ case where time evolution is always well defined. We conclude that the $\\beta_3$ mass term can be pathological and should be treated with care.
Entropy spectrum of charged BTZ black holes in massive gravity's rainbow
Panah, Behzad Eslam
2016-01-01
Regarding the significant interests in massive gravity's rainbow and also BTZ black holes, we apply the formalism introduced by Jiang and Han in order to investigate the quantization of the entropy of black holes. We show that the entropy of BTZ black holes in massive gravity's rainbow is quantized with equally spaced spectra and it depends on the value of the parameters of this black hole such as; massive parameters, electrical charge, the cosmological constant and also rainbow functions.
Perturbations of cosmological and black hole solutions in massive gravity and bi-gravity
Kobayashi, Tsutomu; Siino, Masaru; Yamaguchi, Masahide; Yoshida, Daisuke
2016-10-01
We investigate perturbations of a class of spherically symmetric solutions in massive gravity and bi-gravity. The background equations of motion for the particular class of solutions we are interested in reduce to a set of the Einstein equations with a cosmological constant. Thus, the solutions in this class include all the spherically symmetric solutions in general relativity, such as the Friedmann-Lemaître-Robertson-Walker solution and the Schwarzschild (-de Sitter) solution, though the one-parameter family of two parameters of the theory admits such a class of solutions. We find that the equations of motion for the perturbations of this class of solutions also reduce to the perturbed Einstein equations at first and second order. Therefore, the perturbative stability of the solutions coincides with that of the corresponding solutions in general relativity at least up to the second-order perturbations.
Blasi, Alberto; Maggiore, Nicola
2017-01-01
In this paper we consider the issue of massive gravity from a pure field theoretical point of view, as the massive deformation of the gauge theory for a symmetric rank-2 tensor field. We look for the most general massive theory with well defined propagators, imposing the absence of unphysical poles. We find several possibilities, depending on the choice of the gauge fixing term. Amongst these, two solutions with good massless limit are found. The request of the absence of tachyons, alone, does not isolate the Fierz-Pauli case: several examples of massive theories, which may or may not include the Fierz-Pauli mass term, are given. On the other hand, the Fierz-Pauli theory can be uniquely identified by means of a symmetry: it turns out the the Fierz-Pauli massive gravity is the only element of the cohomology of a BRS operator.
Induced higher-derivative massive gravity on a 2-brane in 4D Minkowski space
Directory of Open Access Journals (Sweden)
D. Bazeia
2015-03-01
Full Text Available 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.
Induced higher-derivative massive gravity on a 2-brane in 4D Minkowski space
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D. [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-970 João Pessoa, Paraíba (Brazil); Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraíba (Brazil); Brito, F.A., E-mail: fabrito@df.ufcg.edu.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-970 João Pessoa, Paraíba (Brazil); Departamento de Física, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraíba (Brazil); Costa, F.G. [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-970 João Pessoa, Paraíba (Brazil); Instituto Federal de Educação, Ciência e Tecnologia da Paraíba (IFPB), Campus Picuí (Brazil)
2015-03-06
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.
Charged black hole solutions in Gauss-Bonnet-massive gravity
Hendi, S. H.; Panahiyan, S.; Panah, B. Eslam
2016-01-01
Motivated by high interest in the close relation between string theory and black hole solutions, in this paper, we take into account the Einstein-Gauss-Bonnet Lagrangian in the context of massive gravity. We examine the possibility of black hole in this regard, and discuss the types of horizons. Next, we calculate conserved and thermodynamic quantities and check the validity of the first law of thermodynamics. In addition, we investigate the stability of these black holes in context of canonical ensemble. We show that number, type and place of phase transition points may be significantly affected by different parameters. Next, by considering cosmological constant as thermodynamical pressure, we will extend phase space and calculate critical values. Then, we construct thermodynamical spacetime by considering mass as thermodynamical potential. We study geometrical thermodynamics of these black holes in context of heat capacity and extended phase space. We show that studying heat capacity, geometrical thermodynamics and critical behavior in extended phase space lead to consistent results. Finally, we will employ a new method for obtaining critical values and show that the results of this method are consistent with those of other methods.
On dRGT massive gravity with degenerate reference metrics
Cao, Li-Ming; Zhang, Yun-Long
2015-01-01
In dRGT massive gravity, to get the equations of motion, the square root tensor is assumed to be invertible in the variation of the action. However, this condition can not be fulfilled when the reference metric is degenerate. This implies that the resulting equations of motion might be different from the case where the reference metric has full rank. In this paper, by generalizing the Moore-Penrose inverse to the symmetric tensor on Lorentz manifolds, we get the equations of motion of the theory with degenerate reference metric. It is found that the equations of motion are a little bit different from those in the non-degenerate cases. Based on the result of the equations of motion, for the $(2+n)$-dimensional solutions with the symmetry of $n$-dimensional maximally symmetric space, we prove a generalized Birkhoff theorem in the case where the degenerate reference metric has rank $n$, i.e., we show that the solutions must be Schwarzschild-type or Nariai-Bertotti-Robinson-type under the assumptions.
Chronology protection in Galileon models and massive gravity
Burrage, Clare; de Rham, Claudia; Heisenberg, Lavinia; Tolley, Andrew J.
2012-07-01
Galileon models are a class of effective field theories that have recently received much attention. They arise in the decoupling limit of theories of massive gravity, and in some cases they have been treated in their own right as scalar field theories with a specific nonlinearly realized global symmetry (Galilean transformation). It is well known that in the presence of a source, these Galileon theories admit superluminal propagating solutions, implying that as quantum field theories they must admit a different notion of causality than standard local Lorentz invariant theories. We show that in these theories it is easy to construct closed timelike curves (CTCs) within the naive regime of validity of the effective field theory. However, on closer inspection we see that the CTCs could never arise since the Galileon inevitably becomes infinitely strongly coupled at the onset of the formation of a CTC. This implies an infinite amount of backreaction, first on the background for the Galileon field, signaling the break down of the effective field theory, and subsequently on the spacetime geometry, forbidding the formation of the CTC. Furthermore the background solution required to create CTCs becomes unstable with an arbitrarily fast decay time. Thus Galileon theories satisfy a direct analogue of Hawking's chronology protection conjecture.
On couplings to matter in massive (bi-)gravity
de Rham, Claudia; Ribeiro, Raquel H
2014-01-01
We investigate the coupling to matter in ghost-free massive (bi-)gravity. When species in the matter sector couple covariantly to only one metric, we show that at one-loop these couplings do not spoil the special structure of the graviton potential. When the same species couples directly to both metrics we show that a ghost is present at the classical level and that loops destroy the special structure of the potential at an unacceptably low scale. We then propose a new `composite' effective metric built out of both metrics. When matter fields couple covariantly to this effective metric, the would be Boulware--Deser ghost is absent in different representative limits. At one-loop such couplings do not detune the special structure of the potential. We conjecture that matter can couple covariantly to that effective metric in all generality without introducing any Boulware-Deser ghost below a cut-off scale parametrically larger than the strong coupling scale. We also discuss alternative couplings to matter where t...
On couplings to matter in massive (bi-)gravity
de Rham, Claudia; Heisenberg, Lavinia; Ribeiro, Raquel H.
2015-02-01
We investigate the coupling to matter in ghost-free massive (bi-)gravity. When species in the matter sector couple covariantly to only one metric, we show that at one-loop these couplings do not spoil the special structure of the graviton potential. When the same species couples directly to both metrics we show that a ghost is present at the classical level and that loops destroy the special structure of the potential at an unacceptably low scale. We then propose a new ‘composite’ effective metric built out of both metrics. When matter fields couple covariantly to this effective metric, the would be Boulware-Deser (BD) ghost is absent in different representative limits. At one-loop such couplings do not detune the special structure of the potential. We conjecture that matter can couple covariantly to that effective metric in all generality without introducing any BD ghost below a cut-off scale parametrically larger than the strong coupling scale. We also discuss alternative couplings to matter where the kinetic and potential terms of the matter field couple to different metrics. In both cases we discuss preliminary implications for cosmology.
Stars and (Furry) Black Holes in Lorentz Breaking Massive Gravity
Comelli, Denis; Pilo, Luigi
2010-01-01
We study the exact spherically symmetric solutions in a class of Lorentz-breaking massive gravity theories, using the effective-theory approach where the graviton mass is generated by the interaction with a suitable set of Stuckelberg fields. We find explicitly the exact black hole solutions which generalizes the familiar Schwarzschild one, which shows a non-analytic hair in the form of a power-like term r^\\gamma. For realistic self-gravitating bodies, we find interesting features, linked to the effective violation of the Gauss law: i) the total gravitational mass appearing in the standard 1/r term gets a multiplicative renormalization proportional to the area of the body itself; ii) the magnitude of the power-like hairy correction is also linked to size of the body. The novel features can be ascribed to presence of the goldstones fluid turned on by matter inside the body; its equation of state approaching that of dark energy near the center. The goldstones fluid also changes the matter equilibrium pressure, ...
Hairy Black Holes in Massive Gravity: Thermodynamics and Phase Structure
Capela, Fabio
2012-01-01
The thermodynamic properties of a static and spherically-symmetric hairy black hole of massive gravity are investigated. The analysis is carried out by enclosing the black hole in a spherical cavity whose surface is maintained at a fixed temperature $T$. It turns out that the ensemble is well-defined only if the "hair" parameter $Q$ characterizing the solution is conserved. Under this condition we compute some relevant thermodynamic quantities, such as thermal energy and entropy, and we study stability and phase structure of the ensemble. In particular, for negative values of the hair parameter, the phase structure is isomorphic to the one of Reissner-Nordstrom black holes in the canonical ensemble. Moreover, the phase-diagram in the plan ($Q,T$) has a line of first-order phase transition that at a critical value of $Q$ terminates in a second-order phase transition. Below this line the dominant phase consists of small, cold black holes that are long-lived and may thus contribute much more to the energy densit...
New Cosmologies on the Horizon. Cosmology and Holography in bigravity and massive gravity
Energy Technology Data Exchange (ETDEWEB)
Tolley, Andrew James [Case Western Reserve Univ., Cleveland, OH (United States)
2013-03-31
The goal of this research program is to explore the cosmological dynamics, the nature of cosmological and black hole horizons, and the role of holography in a new class of infrared modified theories of gravity. This will capitalize of the considerable recent progress in our understanding of the dynamics of massive spin two fields on curved spacetimes, culminating in the formulation of the first fully consistent theories of massive gravity and bigravity/bimetric theories.
On Critical Massive (Super)Gravity in adS(3)
Bergshoeff, Eric A.; Hohm, Olaf; Rosseel, Jan; Sezgin, Ergin; Townsend, Paul K.; Aldaya,; Barcelo, C; Jaramillo, JL
2011-01-01
We review the status of three-dimensional "general massive gravity" (GMG) in its linearization about an anti-de Sitter (adS) vacuum, focusing on critical points in parameter space that yield generalizations of "chiral gravity". We then show how these results extend to,N = 1 super-GMG, expanded about
On Critical Massive (Super)Gravity in adS(3)
Bergshoeff, Eric A.; Hohm, Olaf; Rosseel, Jan; Sezgin, Ergin; Townsend, Paul K.; Aldaya,; Barcelo, C; Jaramillo, JL
2011-01-01
We review the status of three-dimensional "general massive gravity" (GMG) in its linearization about an anti-de Sitter (adS) vacuum, focusing on critical points in parameter space that yield generalizations of "chiral gravity". We then show how these results extend to,N = 1 super-GMG, expanded about
Hendi, S. H.; Eslam Panah, B.; Panahiyan, S.
2016-12-01
Motivated by gauge/gravity group in the low energy effective theory of the heterotic string theory and novel aspects of massive gravity in the context of lattice physics, the minimal coupling of Gauss-Bonnet-massive gravity with Born-Infeld electrodynamics is considered. At first, the metric function is calculated and then the geometrical properties of the solutions are investigated. It is found that there is an essential singularity at the origin and the intrinsic curvature is regular elsewhere. In addition, the effects of massive parameters are studied and black hole solutions with multi horizons are found in this gravity. Also, the conserved and thermodynamic quantities are calculated, and it is shown that the solutions satisfy the first law of thermodynamics. Furthermore, using heat capacity of these black holes, thermal stability and phase transitions are investigated. The variation of different parameters and related modifications on the (number of) phase transition are examined. Next, the critical behavior of the Gauss-Bonnet-Born-Infeld-massive black holes in the context of extended phase space is studied. It is shown how the variation of the different parameters affects the existence and absence of phase transition. Also, it is found that for specific values of different parameters, these black holes may enjoy the existence of a new type of phase transition which to our knowledge was not observed in black hole physics before.
Ionol (BHT) produces superoxide anion.
Smirnova, E G; Lyubimov, Yu I; Malinina, T G; Lyubimova, E Yu; Alexandrushkina, N I; Vanyushin, B F; Kolesova, G M; Yaguzhinsky, L S
2002-11-01
In aqueous medium etiolated wheat seedlings release superoxide anion (O2*-). Interaction of a synthetic antioxidant, butylated hydroxytoluene (BHT, ionol), with oxygen in the aqueous medium is accompanied by O2*- formation. This suggests that under certain conditions BHT behaves as a prooxidant. A natural antioxidant, superoxide dismutase (SOD), and also a wound healing preparation, emulsified denatured placenta (EDP), do not exhibit the prooxidant properties. In contrast to BHT, they reduce O2*- production by the etiolated wheat seedling system.
Hendi, S H; Panahiyan, S
2015-01-01
Motivated by gauge/gravity group in the low energy effective theory of the heterotic string theory, the minimal coupling of Gauss-Bonnet-massive gravity with Born-Infeld electrodynamics is considered. At first the metric function is calculated and then the geometrical properties of the solutions are investigated. It is found that there is an essential singularity at the origin and the intrinsic curvature is regular elsewhere. In addition, the effects of massive parameters on the horizons of black holes are studied and the conserved and thermodynamic quantities are calculated. Also, it is shown that the solutions satisfy the first law of thermodynamics. Furthermore using heat capacity of these black holes, thermal stability and phase transitions are investigated. The variation of different parameters and related modifications on the (number of) phase transition are examined. Next, the critical behavior of the Gauss-Bonnet-Born-Infeld-massive black holes in context of extended phase space is studied. It is show...
Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-Infeld
Jiménez, Jose Beltrán; Olmo, Gonzalo J
2014-01-01
We generalize the ultraviolet sector of gravitation via a Born-Infeld action using lessons from massive gravity. The theory contains all of the elementary symmetric polynomials and is treated in the Palatini formalism. We show how the connection can be solved algebraically to be the Levi-Civita connection of an effective metric. The non-linearity of the algebraic equations yields several branches, one of which always reduces to General Relativity at low curvatures. We explore in detail a minimal version of the theory, for which we study solutions in the presence of a perfect fluid with special attention to the cosmological evolution. In vacuum we recover Ricci-flat solutions, but also an additional physical solution corresponding to an Einstein space. The existence of two physical branches remains for non-vacuum solutions and, in addition, the branch that connects to the Einstein space in vacuum is not very sensitive to the specific value of the energy density. For the branch that connects to the General Rela...
Einstein-Born-Infeld-Massive Gravity: adS-Black Hole Solutions and their Thermal Stability
Hendi, Seyed Hossein; Panahiyan, Shahram
2015-01-01
In this paper, we study massive gravity in the presence of Born-Infeld nonlinear electrodynamics. First, we obtain metric function related to this gravity and investigate the geometry of the solutions and find that there is an essential singularity at the origin ($r=0$). It will be shown that due to contribution of the massive part, the number, types and places of horizons may be changed. Next, we calculate the conserved and thermodynamic quantities and check the validation of the first law of thermodynamics. We also investigate thermal stability of these black holes in context of canonical ensemble. It will be shown that number, type and place of phase transitions points are functions of the different parameters which lead to dependency of stability conditions to these parameters. Also, it will be shown how the behavior of the temperature is modified due to extension of massive gravity and strong nonlinearity parameter.
Cosmology in doubly coupled massive gravity: Constraints from SNIa, BAO and CMB
Heisenberg, Lavinia; Refregier, Alexandre
2016-11-01
Massive gravity in the presence of doubly coupled matter field via en effective composite metric yields an accelerated expansion of the universe. It has been recently shown that the model admits stable de Sitter attractor solutions and could be used as a dark energy model. In this work, we perform a first analysis of the constraints imposed by the SNIa, BAO and CMB data on the massive gravity model with the effective composite metric and show that all the background observations are mutually compatible at the one sigma level with the model.
Cosmology in doubly coupled massive gravity: constraints from SNIa, BAO and CMB
Heisenberg, Lavinia
2016-01-01
Massive gravity in the presence of doubly coupled matter field via en effective composite metric yields an accelerated expansion of the universe. It has been recently shown that the model admits stable de Sitter attractor solutions and could be used as a dark energy model. In this work, we perform a first analysis of the constraints imposed by the SNIa, BAO and CMB data on the massive gravity model with the effective composite metric and show that all the background observations are mutually compatible at the one sigma level with the model.
Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-Infeld
Beltrán Jiménez, Jose; Heisenberg, Lavinia; Olmo, Gonzalo J.
2014-11-01
We generalize the ultraviolet sector of gravitation via a Born-Infeld action using lessons from massive gravity. The theory contains all of the elementary symmetric polynomials and is treated in the Palatini formalism. We show how the connection can be solved algebraically to be the Levi-Civita connection of an effective metric. The non-linearity of the algebraic equations yields several branches, one of which always reduces to General Relativity at low curvatures. We explore in detail a minimal version of the theory, for which we study solutions in the presence of a perfect fluid with special attention to the cosmological evolution. In vacuum we recover Ricci-flat solutions, but also an additional physical solution corresponding to an Einstein space. The existence of two physical branches remains for non-vacuum solutions and, in addition, the branch that connects to the Einstein space in vacuum is not very sensitive to the specific value of the energy density. For the branch that connects to the General Relativity limit we generically find three behaviours for the Hubble function depending on the equation of state of the fluid, namely: either there is a maximum value for the energy density that connects continuously with vacuum, or the energy density can be arbitrarily large but the Hubble function saturates and remains constant at high energy densities, or the energy density is unbounded and the Hubble function grows faster than in General Relativity. The second case is particularly interesting because it could offer an interesting inflationary epoch even in the presence of a dust component. Finally, we discuss the possibility of avoiding certain types of singularities within the minimal model.
BB mode angular power spectrum of CMB from massive gravity
Malsawmtluangi, N
2016-01-01
The primordial massive gravitational waves are placed in the squeezed vacuum state and corresponding $BB$-mode correlation angular power spectrum of the cosmic microwave background is obtained for various slow roll inflation models. The angular power spectrum is compared with the limit of BICEP2/Keck and Planck joint analysis data and the hybrid inflation model is found favorable.
Holographic conductivity in the massive gravity with power-law Maxwell field
Dehyadegari, A.; Kord Zangeneh, M.; Sheykhi, A.
2017-10-01
We obtain a new class of topological black hole solutions in (n + 1)-dimensional massive gravity in the presence of the power-Maxwell electrodynamics. We calculate the conserved and thermodynamic quantities of the system and show that the first law of thermodynamics is satisfied on the horizon. Then, we investigate the holographic conductivity for the four and five dimensional black brane solutions. For completeness, we study the holographic conductivity for both massless (m = 0) and massive (m ≠ 0) gravities with power-Maxwell field. The massless gravity enjoys translational symmetry whereas the massive gravity violates it. For massless gravity, we observe that the real part of conductivity, Re [ σ ], decreases as charge q increases when frequency ω tends to zero, while the imaginary part of conductivity, Im [ σ ], diverges as ω → 0. For the massive gravity, we find that Im [ σ ] is zero at ω = 0 and becomes larger as q increases (temperature decreases), which is in contrast to the massless gravity. It also has a maximum value for ω ≠ 0 which increases with increasing q (with fixed p) or increasing p (with fixed q) for (2 + 1)-dimensional dual system, where p is the power parameter of the power-law Maxwell field. Interestingly, we observe that in contrast to the massless case, Re [ σ ] has a maximum value at ω = 0 (known as the Drude peak) for p = (n + 1) / 4 (conformally invariant electrodynamics) and this maximum increases with increasing q. In this case (m ≠ 0) and for different values of p, the real and imaginary parts of the conductivity has a relative extremum for ω ≠ 0. Finally, we show that for high frequencies, the real part of the holographic conductivity have the power law behavior in terms of frequency, ωa where a ∝ (n + 1 - 4 p). Some similar behaviors for high frequencies in possible dual CFT systems have been reported in experimental observations.
Gravitational lensing of massive particles in Schwarzschild gravity
Liu, Xionghui; Yang, Nan; Jia, Junji
2016-09-01
Both massless light ray and objects with nonzero mass experience trajectory bending in a gravitational field. In this work the bending of trajectories of massive objects in a Schwarzschild spacetime and the corresponding gravitational lensing (GL) effects are studied. A particle sphere for Schwarzschild black hole (BH) is found with its radius a simple function of the particle velocity and proportional to the BH mass. A single master formula for both the massless and massive particle bending angle is found, in the form of an elliptic function depending only on the velocity and impact parameter. This bending angle is expanded in both large and small velocity limits and large and small impact parameter limits. The corresponding deflection angle for weak and strong GL of massive particles are analyzed, and their corrections to the light ray deflection angles are obtained. The dependence of the deflection angles on the source angle and the particle speed is investigated. Finally we discuss the potential applications of the results in hypervelocity star observations and in determining mass/mass hierarchy of slow particles/objects.
Covariant constraints for generic massive gravity and analysis of its characteristics
DEFF Research Database (Denmark)
Deser, S.; Sandora, M.; Waldron, A.;
2014-01-01
We perform a covariant constraint analysis of massive gravity valid for its entire parameter space, demonstrating that the model generically propagates 5 degrees of freedom; this is also verified by a new and streamlined Hamiltonian description. The constraint's covariant expression permits...
Einstein-Born-Infeld-massive gravity: adS-black hole solutions and their thermodynamical properties
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H. [Physics Department and Biruni Observatory, College of Sciences, Shiraz University,Shiraz 71454 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM),P.O. Box 55134-441, Maragha (Iran, Islamic Republic of); Panah, B. Eslam; Panahiyan, S. [Physics Department and Biruni Observatory, College of Sciences, Shiraz University,Shiraz 71454 (Iran, Islamic Republic of)
2015-11-23
In this paper, we study massive gravity in the presence of Born-Infeld nonlinear electrodynamics. First, we obtain metric function related to this gravity and investigate the geometry of the solutions and find that there is an essential singularity at the origin (r=0). It will be shown that due to contribution of the massive part, the number, type and place of horizons may be changed. Next, we calculate the conserved and thermodynamic quantities and check the validation of the first law of thermodynamics. We also investigate thermal stability of these black holes in context of canonical ensemble. It will be shown that number, type and place of phase transition points are functions of different parameters which lead to dependency of stability conditions to these parameters. Also, it will be shown how the behavior of temperature is modified due to extension of massive gravity and strong nonlinearity parameter. Next, critical behavior of the system in extended phase space by considering cosmological constant as pressure is investigated. A study regarding neutral Einstein-massive gravity in context of extended phase space is done. Geometrical approach is employed to study the thermodynamical behavior of the system in context of heat capacity and extended phase space. It will be shown that GTs, heat capacity and extended phase space have consistent results. Finally, critical behavior of the system is investigated through use of another method. It will be pointed out that the results of this method is in agreement with other methods and follow the concepts of ordinary thermodynamics.
Dirac quasinormal modes of new type black holes in new massive gravity
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)
2014-07-15
We study a new type of black holes in three-dimensional new massive gravity and we calculate analytically the quasinormal modes for fermionic perturbations for some special cases. Then we show that for these cases black holes of the new type are stable under fermionic field perturbations. (orig.)
Exact Solutions in Modified Massive Gravity and Off-Diagonal Wormhole Deformations
Vacaru, Sergiu I
2014-01-01
There are explored off-diagonal deformations of "prime" metrics in Einstein gravity (for instance, for wormhole configurations) into "target" exact solutions in f(R,T)-modified and massive/ bi-metric gravity theories. The new classes of solutions may posses, or not, Killing symmetries and can be characterized by effective induced masses, anisotropic polarized interactions and cosmological constants. For nonholonomic deformations with (conformal) ellipsoid/ toroid and/or solitonic symmetries and, in particular, for small eccentricity rotoid configurations, we can generate wormholes like objects matching external black ellipsoid - de Sitter geometries. We conclude that there are nonholonomic transforms and/or non-trivial limits to exact solutions in general relativity when modified/ massive gravity effects are modeled by off-diagonal and/or nonholonomic parametric interactions.
Exact solutions in modified massive gravity and off-diagonal wormhole deformations
Energy Technology Data Exchange (ETDEWEB)
Vacaru, Sergiu I. [Alexandru Ioan Cuza University, Rector' s Office, Iasi (Romania); CERN, Theory Division, Geneva 23 (Switzerland)
2014-03-15
We explore off-diagonal deformations of 'prime' metrics in Einstein gravity (for instance, for wormhole configurations) into 'target' exact solutions in f(R,T)-modified and massive/bi-metric gravity theories. The new classes of solutions may, or may not, possess Killing symmetries and can be characterized by effective induced masses, anisotropic polarized interactions, and cosmological constants. For nonholonomic deformations with (conformal) ellipsoid/ toroid and/or solitonic symmetries and, in particular, for small eccentricity rotoid configurations, we can generate wormhole-like objects matching an external black ellipsoid--de Sitter geometries. We conclude that there are nonholonomic transforms and/or non-trivial limits to exact solutions in general relativity when modified/massive gravity effects are modeled by off-diagonal and/or nonholonomic parametric interactions. (orig.)
A spectre is haunting the cosmos: Quantum stability of massive gravity with ghosts
Könnig, Frank; Akrami, Yashar; Amendola, Luca; Zumalacárregui, Miguel
2016-01-01
Many theories of modified gravity with higher order derivatives are usually ignored because of serious problems that appear due to an additional ghost degree of freedom. Most dangerously, it causes an immediate decay of the vacuum. However, breaking Lorentz invariance can cure such abominable behavior. By analyzing a model that describes a massive graviton together with a remaining Boulware-Deser ghost mode we show that even ghostly theories of modified gravity can yield models that are viable at both classical and quantum levels and, therefore, they should not generally be ruled out. Furthermore, we identify the most dangerous quantum scattering process that has the main impact on the decay time and find differences to simple theories that only describe an ordinary scalar field and a ghost. Additionally, constraints on the parameters of the theory including some upper bounds on the Lorentz-breaking cutoff scale are presented. In particular, for a simple theory of massive gravity we find that a Lorentz violat...
External stability for Spherically Symmetric Solutions in Lorentz Breaking Massive Gravity
Addazi, Andrea
2014-01-01
We discuss spherically symmetric solutions for Stars and Black Holes in a class of Lorentz-breaking massive gravity theories. This analysis is valid both for St\\"uckelberg's effective field theory formulation and for Lorentz Breaking Massive Bigravity. The approach consists in analyzing the stability of the geodesic equations out to the star radius, at the first order (deviation equation). The main result is a strong constrain in the the space of parameters of the theory. This strongly motivates an higher order geodetic analysis of perturbations, to understand if it exists a class of spherically symmetric Lorentz-breaking massive gravity solutions for stars, black holes, and, in general, self-gravitating systems stable and phenomenologically acceptable.
Holographic thermalization and generalized Vaidya-AdS solutions in massive gravity
Hu, Ya-Peng; Zeng, Xiao-Xiong; Zhang, Hai-Qing
2017-02-01
We investigate the effect of massive graviton on the holographic thermalization process. Before doing this, we first find out the generalized Vaidya-AdS solutions in the de Rham-Gabadadze-Tolley (dRGT) massive gravity by directly solving the gravitational equations. Then, we study the thermodynamics of these Vaidya-AdS solutions by using the Misner-Sharp energy and unified first law, which also shows that the massive gravity is in a thermodynamic equilibrium state. Moreover, we adopt the two-point correlation function at equal time to explore the thermalization process in the dual field theory, and to see how the graviton mass parameter affects this process from the viewpoint of AdS/CFT correspondence. Our results show that the graviton mass parameter will increase the holographic thermalization process.
Holographic Thermalization and Generalized Vaidya-AdS Solutions in Massive Gravity
Hu, Ya-Peng; Zhang, Hai-Qing
2016-01-01
We investigate the effect of massive graviton on the holographic thermalization process. Before doing this, we first find out the generalized Vaidya-AdS solutions in the de Rham-Gabadadze-Tolley (dRGT) massive gravity by directly solving the gravitational equations. Then, we study the thermodynamics of these Vaidya-AdS solutions by using the Minsner-Sharp energy and unified first law, which also shows that the massive gravity is in a thermodynamic equilibrium state. Moreover, we adopt the two-point correlation function at equal time to explore the thermalization process in the dual field theory, and to see how the graviton mass parameter affects this process from the viewpoint of AdS/CFT correspondence. Our results show that the graviton mass parameter will increase the holographic thermalization process.
Holographic thermalization and generalized Vaidya-AdS solutions in massive gravity
Directory of Open Access Journals (Sweden)
Ya-Peng Hu
2017-02-01
Full Text Available We investigate the effect of massive graviton on the holographic thermalization process. Before doing this, we first find out the generalized Vaidya-AdS solutions in the de Rham–Gabadadze–Tolley (dRGT massive gravity by directly solving the gravitational equations. Then, we study the thermodynamics of these Vaidya-AdS solutions by using the Misner–Sharp energy and unified first law, which also shows that the massive gravity is in a thermodynamic equilibrium state. Moreover, we adopt the two-point correlation function at equal time to explore the thermalization process in the dual field theory, and to see how the graviton mass parameter affects this process from the viewpoint of AdS/CFT correspondence. Our results show that the graviton mass parameter will increase the holographic thermalization process.
Ghosts and matter couplings in massive gravity, bigravity and multigravity
de Rham, Claudia; Heisenberg, Lavinia; Ribeiro, Raquel H.
2014-12-01
Recently, several works have investigated the coupling to matter in ghost-free massive bigravity and multigravity and a new effective coupling to matter has been proposed. In this paper we clarify some confusion on the existence and the implications of a ghost above the strong coupling scale. We confirm that the standard constraint which is otherwise typically present in this type of theories disappears on generic backgrounds as soon as this new coupling is considered. This implies the reemergence of the Boulware-Deser ghost. Nevertheless the absence of ghost in the decoupling limit implies that the cutoff scale (if identified with the scale at which the ghost enters) is higher than the strong coupling scale. Therefore there is a valid interesting region of applicability for these couplings at scales below the cutoff.
Galileons Coupled to Massive Gravity: General Analysis and Cosmological Solutions
Goon, Garrett; Hinterbichler, Kurt; Mukohyama, Shinji; Trodden, Mark
2014-01-01
We further develop the framework for coupling galileons and Dirac-Born-Infeld (DBI) scalar fields to a massive graviton while retaining both the non-linear symmetries of the scalars and ghost-freedom of the theory. The general construction is recast in terms of vielbeins which simplifies calculations and allows for compact expressions. Expressions for the general form of the action are derived, with special emphasis on those models which descend from maximally symmetric spaces. We demonstrate the existence of maximally symmetric solutions to the fully non-linear theory and analyze their spectrum of quadratic fluctuations. Finally, we consider self-accelerating cosmological solutions and study their perturbations, showing that the vector and scalar modes have vanishing kinetic terms.
Quantum Aspects of Massive Gravity II: Non-Pauli-Fierz Theory
Park, Minjoon
2010-01-01
We investigate the non-Pauli-Fierz (nPF) theory, a linearized massive gravity with a generic graviton mass term, which has been ignored due to a ghost in its spectrum and the resultant loss of unitarity. We first show that it is possible to use the Lee-Wick mechanism, a unitarization through the decay of a ghost, in order to handle the sixth mode ghost of nPF, and then check for the quantum consistency. Once proven to be consistent, nPF could become a viable candidate for a large distance modification of gravity, because it naturally solves the intrinsic problems that most dark energy/modified gravity models suffer from: It smoothly converges to general relativity at short distances, and the small graviton mass necessary to modify gravity at large scales is radiatively stable.
Quasi-local conserved charges of spin-3 topologically massive gravity
Directory of Open Access Journals (Sweden)
M.R. Setare
2016-08-01
Full Text Available In this paper we obtain conserved charges of spin-3 topologically massive gravity by using a quasi-local formalism. We find a general formula to calculate conserved charge of the spin-3 topologically massive gravity which corresponds to a Killing vector field ξ. We show that this general formula reduces to the previous one for the ordinary spin-3 gravity presented in [18] when we take into account only transformation under diffeomorphism, without considering generalized Lorentz gauge transformation (i.e. λξ=0, and by taking 1μ→0. Then we obtain a general formula for the entropy of black hole solutions of the spin-3 topologically massive gravity. Finally we apply our formalism to calculate energy, angular momentum and entropy of a special black hole solution and we find that obtained results are consistent with previous results in the limiting cases. Moreover our results for energy, angular momentum and entropy are consistent with the first law of black hole mechanics.
Massive gravitational waves from f(R) theories of gravity: Potential detection with LISA
Energy Technology Data Exchange (ETDEWEB)
Capozziello, Salvatore [Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' , INFN Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Edificio G, via Cintia, I-80126 Napoli (Italy)], E-mail: capozzie@na.infn.it; Corda, Christian [Associazione Galileo Galilei, via Pier Cironi 16, 59100 Prato (Italy); Centro di Scienze Naturali, via di Galceti 74, 59100 Prato (Italy)], E-mail: christian.corda@ego-gw.it; De Laurentis, Maria Felicia [Relativity and Gravitation Group, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy)], E-mail: mariafelicia.delaurentist@polito.it
2008-11-27
This Letter is a generalization of previous results on gravitational waves (GWs) from f(R) theories of gravity. In some previous papers, particular f(R) theories have been linearized for the first time in the literature. Now, the process is further generalized, showing that every f(R) theory can be linearized producting a third massive mode of gravitational radiation. In this framework, previous results are particular cases of the more general problem that is discussed in this Letter. The potential detectability of such massive GWs with LISA is also discussed with the auxilium of longitudinal response functions.
Massive gravitational waves from f(R) theories of gravity: Potential detection with LISA
Capozziello, Salvatore; De Laurentis, Maria Felicia
2008-01-01
This letter is a generalization of previous results on gravitational waves (GWs) from f(R) theories of gravity. In some previous papers, particular f(R) theories have been linearized for the first time in the literature. Now, the process is further generalized, showing that every f(R) theory can be linearized producting a third massive mode of gravitational radiation. In this framework, previous results are particular cases of the more general problem that is discussed in this letter. The potential detectability of such massive GWs with LISA is also discussed with the auxilium of longitudinal response functions.
P-V criticality in AdS black holes of massive gravity
Fernando, Sharmanthie
2016-01-01
In this paper we have studied the extended phase space thermodynamics in the canonical ensemble of black holes in massive gravity in AdS space. The black holes considered here belong to a theory of massive gravity where the graviton gain a mass due to Lorenz symmetry breaking. We have computed various thermodynamical quantities such as temperature, pressure, Gibbs free energy and specific heat capacity. The local and the global thermodynamical stability of the black holes are studied in detail. For a specific value of the parameter in the theory, the black holes undergo a first order phase transition similar to the Van der Waals phase transitions between gas and liquid under constant temperature. This transition is between the small and the large black hole. The critical exponents are computed at the critical values and shown to be the same as for the Van der Waals critical exponents.
Anomalies and Hawking fluxes from the black holes of topologically massive gravity
Porfyriadis, Achilleas P
2009-01-01
The anomaly cancelation method proposed by Wilczek et al. is applied to the black holes of topologically massive gravity (TMG) and topologically massive gravito-electrodynamics (TMGE). Thus the Hawking temperature and fluxes of the ACL and ACGL black holes are found. The Hawking temperatures obtained agree with the surface gravity formula. Both black holes are rotating and this gives rise to appropriate terms in the effective U(1) gauge field of the reduced (1+1)-dimensional theory. It is found that the terms in this U(1) gauge field correspond exactly to the correct angular velocities on the horizon of both black holes as well as the correct electrostatic potential of the ACGL black hole. So the results for the Hawking fluxes derived here from the anomaly cancelation method, are in complete agreement with the ones obtained from integrating the Planck distribution.
Covariant constraints for generic massive gravity and analysis of its characteristics
Deser, S; Waldron, A; Zahariade, G
2014-01-01
We perform a covariant constraint analysis of massive gravity valid for its entire parameter space, demonstrating that the model generically propagates five degrees of freedom; this is also verified by a new and streamlined Hamiltonian description. The constraint's covariant expression permits computation of the model's caustics. Although new features such as the dynamical Riemann tensor appear in the characteristic matrix, the model still exhibits the pathologies uncovered in earlier work: superluminality and likely acausalities.
Dereli, Tekin; Yetişmişoǧlu, Cem
2016-09-01
We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti-de Sitter space AdS3) and constant torsion provide exact solutions.
Dereli, T
2016-01-01
We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space $AdS_3$) and constant torsion provide exact solutions.
Breaking the Cosmic Degeneracy between Modified Gravity and Massive Neutrinos with the Cosmic Web
Shim, Junsup; Baldi, Marco
2014-01-01
In a recent work, Baldi et al. highlighted the issue of cosmic degeneracies, consisting in the fact that the standard statistics of the large-scale structure might not be sufficient to conclusively test cosmological models beyond $\\Lambda $CDM when multiple extensions of the standard scenario coexist in nature. In particular, it was shown that the characteristic features of an $f(R)$ Modified Gravity theory and of massive neutrinos with an appreciable total mass $\\Sigma _{i}m_{\
Charged BTZ black holes in the context of massive gravity's rainbow
Hendi, S H; Upadhyay, S; Panah, B Eslam
2016-01-01
Regarding the significant interests in thermodynamics of black objects, we examine charged BTZ black holes. We consider massive gravity context with an energy dependent spacetime to enrich the results. In addition, we consider all the constants as energy dependant ones. We investigate thermodynamic properties of the solutions by calculating the heat capacity and free energy. We also analyze thermal stability and study the possibility of Hawking-Page phase transition. At last, we study geometrical thermodynamics of these black holes.
Novel symmetries in Weyl-invariant gravity with massive gauge field
Energy Technology Data Exchange (ETDEWEB)
Abhinav, K. [S.N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata (India); Shukla, A.; Panigrahi, P.K. [Indian Institute of Science Education and Research Kolkata, Mohanpur (India)
2016-11-15
The background field method is used to linearize the Weyl-invariant scalar-tensor gravity, coupled with a Stueckelberg field. For a generic background metric, this action is found not to be invariant, under both a diffeomorphism and generalized Weyl symmetry, the latter being a combination of gauge and Weyl transformations. Interestingly, the quadratic Lagrangian, emerging from a background of Minkowski metric, respects both transformations independently. The Becchi-Rouet-Stora-Tyutin symmetry of scalar-tensor gravity coupled with a Stueckelberg-like massive gauge particle, possessing a diffeomorphism and generalized Weyl symmetry, reveals that in both cases negative-norm states with unphysical degrees of freedom do exist. We then show that, by combining diffeomorphism and generalized Weyl symmetries, all the ghost states decouple, thereby removing the unphysical redundancies of the theory. During this process, the scalar field does not represent any dynamic mode, yet modifies the usual harmonic gauge condition through non-minimal coupling with gravity. (orig.)
Generalized Vaidya Solutions and Misner-Sharp mass for $n$-dimensional massive gravity
Hu, Ya-Peng; Zhang, Hongsheng
2016-01-01
Dynamical solutions are always of interests in gravity theories. We derive a series of generalized Vaidya solutions in the $n$-dimensional de Rham-Gabadadze-Tolley (dRGT) massive gravity with a singular reference metric. Similar to the case of the Einstein gravity, the generalized Vaidya solution can describe shining/absorbing stars. Moreover, we also find a more general Vaidya-like solution by introducing a more generic matter field than the pure radiation in the original Vaidya solution. As a result, the above generalized Vaidya solution is naturally included in this Vaidya-like solution as a special case. We investigate the thermodynamics for this Vaidya-like spacetime by using the unified first law, and present the generalized Misner-Sharp mass. Our results show that the generalized Minser-Sharp mass does exist in this spacetime. In addition, the usual Clausius relation $\\delta Q= TdS$ holds on the apparent horizon, which implicates that the massive gravity is in a thermodynamic equilibrium state. We find...
A Covariant Master Theory for Novel Galilean Invariant Models and Massive Gravity
Gabadadze, Gregory; Khoury, Justin; Pirtskhalava, David; Trodden, Mark
2012-01-01
Coupling the galileons to a curved background has been a tradeoff between maintaining second order equations of motion, maintaining the galilean shift symmetries, and allowing the background metric to be dynamical. We propose a construction which can achieve all three for a novel class of galilean invariant models, by coupling a scalar with the galilean symmetry to a massive graviton. This generalizes the brane construction for galileons, by adding to the brane a dynamical metric, (non-universally) interacting with the galileon field. Alternatively, it can be thought of as an extension of the ghost-free massive gravity, or as a massive graviton-galileon scalar-tensor theory. In the decoupling limit of these theories, new kinds of galileon invariant interactions arise between the scalar and the longitudinal mode of the graviton. These have higher order equations of motion and infinite powers of the field, yet are ghost-free.
Primordial massive gravitational waves from Einstein-Chern-Simons-Weyl gravity
Energy Technology Data Exchange (ETDEWEB)
Myung, Yun Soo; Moon, Taeyoon, E-mail: ysmyung@inje.ac.kr, E-mail: tymoon@inje.ac.kr [Institute of Basic Sciences and Department of Computer Simulation, Inje University, Gimhae 621-749 (Korea, Republic of)
2014-08-01
We investigate the evolution of cosmological perturbations during de Sitter inflation in the Einstein-Chern-Simons-Weyl gravity. Primordial massive gravitational waves are composed of one scalar, two vector and four tensor circularly polarized modes. We show that the vector power spectrum decays quickly like a transversely massive vector in the superhorizon limit z → 0. In this limit, the power spectrum coming from massive tensor modes decays quickly, leading to the conventional tensor power spectrum. Also, we find that in the limit of m{sup 2} → 0 (keeping the Weyl-squared term only), the vector and tensor power spectra disappear. It implies that their power spectra are not gravitationally produced because they (vector and tensor) are decoupled from the expanding de Sitter background, as a result of conformal invariance.
Evolution of massive fields around a black hole in Horava gravity
Varghese, Nijo
2010-01-01
We study the time evolution of massive scalar field in the spacetime geometry of Kehagias-Sfetsos(KS) black hole in deformed Ho\\v{r}ava-Lifshitz(HL) gravity by numerical analysis. We find that the signature of HL theory is encoded in the quasinormal ringdown(QNM) phase of evolution of field. The QNM region in the evolution process lasts for a longer time. QNMs involved in the evolution of massive field are calculated from the time domain integration data and the third order WKB method and find that they have a higher oscillation frequency and a lower damping rate than the Schwarzschild spacetime case. We also study the intermediate late time behavior of evolution and show that this phase is dominated by the oscillatory inverse power-law tail for the massive fields and is identical to the Schwarzschild case.
Kwantitatieve bepaling van BHT in melkpoeder
Oostrom, van J.J.; Hollman, P.
1985-01-01
Gezocht is naar een snelle eenvoudige methode voor de bepaling van BHT in melkpoeder. De bestaande multi-methode voor antioxidanten werd aangepast, waarbij de extractie vereenvoudigd werd en de chromatografische condities geoptimaliseerd werden in relatie tot BHT.
Pitts, J. Brian
2016-02-01
What if gravity satisfied the Klein-Gordon equation? Both particle physics from the 1920-30s and the 1890s Neumann-Seeliger modification of Newtonian gravity with exponential decay suggest considering a "graviton mass term" for gravity, which is algebraic in the potential. Unlike Nordström's "massless" theory, massive scalar gravity is strictly special relativistic in the sense of being invariant under the Poincaré group but not the 15-parameter Bateman-Cunningham conformal group. It therefore exhibits the whole of Minkowski space-time structure, albeit only indirectly concerning volumes. Massive scalar gravity is plausible in terms of relativistic field theory, while violating most interesting versions of Einstein's principles of general covariance, general relativity, equivalence, and Mach. Geometry is a poor guide to understanding massive scalar gravity(s): matter sees a conformally flat metric due to universal coupling, but gravity also sees the rest of the flat metric (barely or on long distances) in the mass term. What is the 'true' geometry, one might wonder, in line with Poincaré's modal conventionality argument? Infinitely many theories exhibit this bimetric 'geometry,' all with the total stress-energy's trace as source; thus geometry does not explain the field equations. The irrelevance of the Ehlers-Pirani-Schild construction to a critique of conventionalism becomes evident when multi-geometry theories are contemplated. Much as Seeliger envisaged, the smooth massless limit indicates underdetermination of theories by data between massless and massive scalar gravities-indeed an unconceived alternative. At least one version easily could have been developed before General Relativity; it then would have motivated thinking of Einstein's equations along the lines of Einstein's newly re-appreciated "physical strategy" and particle physics and would have suggested a rivalry from massive spin 2 variants of General Relativity (massless spin 2, Pauli and Fierz
2010-04-01
... Preservatives § 172.115 BHT. The food additive BHT (butylated hydroxytoluene), alone or in combination with... 21 Food and Drugs 3 2010-04-01 2009-04-01 true BHT. 172.115 Section 172.115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...
Bičák, Jiří
2016-01-01
The question of the uniqueness of energy-momentum tensors in the linearized general relativity and in the linear massive gravity is analyzed without using variational techniques. We start from a natural ansatz for the form of the tensor (for example, that it is a linear combination of the terms quadratic in the first derivatives), and require it to be conserved as a consequence of field equations. In the case of the linear gravity in a general gauge we find a four-parametric system of conserved second-rank tensors which contains a unique symmetric tensor. This turns out to be the linearized Landau-Lifshitz pseudotensor employed often in full general relativity. We elucidate the relation of the four-parametric system to the expression proposed recently by Butcher et al. "on physical grounds" in harmonic gauge, and we show that the results coincide in the case of high-frequency waves in vacuum after a suitable averaging. In the massive gravity we show how one can arrive at the expression which coincides with th...
Li, Ping; Li, Xin-zhou; Xi, Ping
2016-06-01
We present a detailed study of the spherically symmetric solutions in Lorentz-breaking massive gravity. There is an undetermined function { F }(X,{w}1,{w}2,{w}3) in the action of Stückelberg fields {S}φ ={{{Λ }}}4\\int {{{d}}}4x\\sqrt{-g}{ F }, which should be resolved through physical means. In general relativity, the spherically symmetric solution to the Einstein equation is a benchmark and its massive deformation also plays a crucial role in Lorentz-breaking massive gravity. { F } will satisfy the constraint equation {T}01=0 from the spherically symmetric Einstein tensor {G}01=0, if we maintain that any reasonable physical theory should possess the spherically symmetric solutions. The Stückelberg field {φ }i is taken as a ‘hedgehog’ configuration {φ }i=φ (r){x}i/r, whose stability is guaranteed by the topological one. Under this ansätz, {T}01=0 is reduced to d{ F }=0. The functions { F } for d{ F }=0 form a commutative ring {R}{ F }. We obtain an expression of the solution to the functional differential equation with spherical symmetry if { F }\\in {R}{ F }. If { F }\\in {R}{ F } and \\partial { F }/\\partial X=0, the functions { F } form a subring {S}{ F }\\subset {R}{ F }. We show that the metric is Schwarzschild, Schwarzschild-AdS or Schwarzschild-dS if { F }\\in {S}{ F }. When { F }\\in {R}{ F } but { F }\
P-V criticality in the extended phase space of black holes in massive gravity
Xu, Jianfei; Hu, Ya-Peng
2015-01-01
We study the P-V criticality and phase transition in the extended phase space of charged anti-de Sitter black holes in canonical ensemble of ghost-free massive gravity, where the cosmological constant is viewed as a dynamical pressure of the black hole system. We give the generalized thermodynamic first law and the Smarr relation with massive gravity correction. We find that not only when the horizon topology is spherical but also in the Ricci flat or hyperbolic case, there appear the P-V criticality and phase transition up to the combination k+c02c2m2 in the four-dimensional case, where k characterizes the horizon curvature and c2m2 is the coefficient of the second term of massive potential associated with the graviton mass. The positivity of such combination indicate the van der Waals-like phase transition. When the spacetime dimension is larger then four, the Maxwell charge there seems unnecessary for the appearance of critical behavior, but a infinite repulsion effect needed, which can also be realized th...
Reply to ''Comment on 'Quantum massive conformal gravity' by F. F. Faria''
Energy Technology Data Exchange (ETDEWEB)
Faria, F.F. [Universidade Estadual do Piaui, Centro de Ciencias da Natureza, Teresina, PI (Brazil)
2017-01-15
Recently in (Eur Phys J C 76:341, 2016), Myung has suggested that the renormalizability of massive conformal gravity is meaningless unless the massive ghost states of the theory are stable. Here we show that massive conformal gravity can be renormalizable having unstable ghost states. (orig.)
Cosmological perturbations of self-accelerating universe in nonlinear massive gravity
Gumrukcuoglu, A Emir; Mukohyama, Shinji
2011-01-01
We study cosmological perturbations of self-accelerating universe solutions in the recently proposed nonlinear theory of massive gravity, with general matter content. While the broken diffeomorphism invariance implies that there generically are 2 tensor, 2 vector and 2 scalar degrees of freedom in the gravity sector, we find that the scalar and vector degrees have vanishing kinetic terms and nonzero mass terms. Depending on their nonlinear behavior, this indicates either nondynamical nature of these degrees or strong couplings. Assuming the former, we integrate out the 2 vector and 2 scalar degrees of freedom. We then find that in the scalar and vector sectors, gauge-invariant variables constructed from metric and matter perturbations have exactly the same quadratic action as in general relativity. The difference from general relativity arises only in the tensor sector, where the graviton mass modifies the dispersion relation of gravitational waves, with a time-dependent effective mass. This may lead to modif...
On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity
Directory of Open Access Journals (Sweden)
Qing-Guo Huang
2015-09-01
Full Text Available In de Rham–Gabadadze–Tolley (dRGT massive gravity and bi-gravity, a non-minimal matter coupling involving both metrics generically reintroduces the Boulware–Deser (BD ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, the absence of Ostrogradski ghosts in the decoupling limit and the absence of the BD ghost from matter quantum loop corrections.
On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity
Energy Technology Data Exchange (ETDEWEB)
Huang, Qing-Guo, E-mail: huangqg@itp.ac.cn [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Ribeiro, Raquel H., E-mail: R.Ribeiro@qmul.ac.uk [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom); CERCA/Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106 (United States); Xing, Yu-Hang, E-mail: xingyh@itp.ac.cn [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Zhang, Ke-Chao, E-mail: zkc@itp.ac.cn [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Zhou, Shuang-Yong, E-mail: sxz353@case.edu [CERCA/Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106 (United States)
2015-09-02
In de Rham–Gabadadze–Tolley (dRGT) massive gravity and bi-gravity, a non-minimal matter coupling involving both metrics generically reintroduces the Boulware–Deser (BD) ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, the absence of Ostrogradski ghosts in the decoupling limit and the absence of the BD ghost from matter quantum loop corrections.
Massive, massless and ghost modes of gravitational waves from higher-order gravity
Bogdanos, Charalampos; De Laurentis, Mariafelicia; Nesseris, Savvas
2009-01-01
We linearize the field equations for higher order theories that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes with the latter being, in general, ghost modes. Then, we investigate the possible detectability of such additional polarization modes of a stochastic gravitational wave by ground-based and space interferometric detectors. Finally, we extend the formalism of the cross-correlation analysis, including the additional polarization modes, and calculate the detectable energy density of the spectrum for a stochastic background of the relic gravity waves that corresponds to our model. For the situation considered here, we find that these massive modes are certainly of interest for direct detection by the LISA experiment.
Stability of warped AdS3 black holes in Topologically Massive Gravity under scalar perturbations
Ferreira, Hugo R C
2013-01-01
We demonstrate that the warped AdS3 black hole solutions of Topologically Massive Gravity are classically stable against massive scalar field perturbations by analysing the quasinormal and bound state modes of the scalar field. In particular, it is found that although classical superradiance is present it does not give rise to superradiant instabilities. The stability is shown to persist even when the black hole is enclosed by a stationary mirror with Dirichlet boundary conditions. This is a surprising result in view of the similarity between the causal structure of the warped AdS3 black hole and the Kerr spacetime in 3+1 dimensions. This work provides the foundations for the study of quantum field theory in this spacetime.
Black holes in massive gravity: quasinormal modes of Dirac field perturbations
Fernando, Sharmanthie
2015-01-01
We have studied quasinormal modes of spinor $\\frac{1}{2}$, massless Dirac field perturbations of a black hole in massive gravity. The parameters of the theory, such as the mass of the black hole, the scalar charge of the black hole, mode number and the multipole number are varied to observe how the corresponding quasinormal frequencies change. We have also used the P$\\ddot{o}$schl-Teller approximation to reach analytical values for the frequencies of quasinormal modes for comparison with the numerically obtained values. Comparisons are done with the frequencies of the Schwarzschild black hole.
Quasinormal modes of BTZ black hole in spin-3 topologically massive gravity
Myung, Yun Soo; Park, Young-Jai
2012-01-01
Using the operator approach, we obtain quasinormal modes (QNMs) of BTZ black hole in spin-3 topologically massive gravity by solving the first-order equation of motion with the transverse-traceless condition. It seems that these are different from those obtained when solving the second-order differential equation for the third-rank tensor of spin-3 field, which are imposed by the boundary conditions and have the sign ambiguity of mass. However, it is shown clearly that two approaches to the left-moving QNMs are identical, while the right-moving QNMs of solving the second-order equation are given by descendants of the operator approach.
Directory of Open Access Journals (Sweden)
S.H. Hendi
2017-06-01
Full Text Available Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
Is there vacuum when there is mass? Vacuum and non-vacuum solutions for massive gravity
Martín-Moruno, Prado; Visser, Matt
2013-08-01
Massive gravity is a theory which has a tremendous amount of freedom to describe different cosmologies, but at the same time, the various solutions one encounters must fulfil some rather nontrivial constraints. Most of the freedom comes not from the Lagrangian, which contains only a small number of free parameters (typically three depending on counting conventions), but from the fact that one is in principle free to choose the reference metric almost arbitrarily—which effectively introduces a non-denumerable infinity of free parameters. In the current paper, we stress that although changing the reference metric would lead to a different cosmological model, this does not mean that the dynamics of the universe can be entirely divorced from its matter content. That is, while the choice of reference metric certainly influences the evolution of the physically observable foreground metric, the effect of matter cannot be neglected. Indeed the interplay between matter and geometry can be significantly changed in some specific models; effectively since the graviton would be able to curve the spacetime by itself, without the need of matter. Thus, even the set of vacuum solutions for massive gravity can have significant structure. In some cases, the effect of the reference metric could be so strong that no conceivable material content would be able to drastically affect the cosmological evolution. Dedicated to the memory of Professor Pedro F González-Díaz
A class of black holes in dRGT massive gravity and their thermodynamical properties
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Suchant G. [Jamia Millia Islamia, Centre of Theoretical Physics, New Delhi (India); University of Kwazulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Private Bag 54001, Durban (South Africa); Tannukij, Lunchakorn [Mahidol University, Department of Physics, Faculty of Science, Bangkok (Thailand); Wongjun, Pitayuth [Naresuan University, The Institute for Fundamental Study, Phitsanulok (Thailand); Ministry of Education, Thailand Center of Excellence in Physics, Bangkok (Thailand)
2016-03-15
We present an exact spherical black hole solution in de Rham, Gabadadze, and Tolley (dRGT) massive gravity for a generic choice of the parameters in the theory, and also discuss the thermodynamical and phase structure of the black hole in both the grand canonical and the canonical ensembles (for the charged case). It turns out that the dRGT black hole solution includes other known solutions to the Einstein field equations, such as the monopole-de Sitter-Schwarzschild solution with the coefficients of the third and fourth terms in the potential and the graviton mass in massive gravity naturally generates the cosmological constant and the global monopole term. Furthermore, we compute the mass, temperature and entropy of the dRGT black hole, and also perform thermodynamical stability analysis. It turns out that the presence of the graviton mass completely changes the black hole thermodynamics, and it can provide the Hawking-Page phase transition which also occurs for the charged black holes. Interestingly, the entropy of a black hole is barely affected and still obeys the standard area law. In particular, our results, in the limit m{sub g} → 0, reduced exactly to the results of general relativity. (orig.)
Off-diagonal ekpyrotic scenarios and equivalence of modified, massive and/or Einstein gravity
Directory of Open Access Journals (Sweden)
Sergiu I. Vacaru
2016-01-01
Full Text Available Using our anholonomic frame deformation method, we show how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates and undergoing a phase of ultra-slow contraction can be constructed in massive gravity. In this paper, there are found and studied new classes of locally anisotropic and (inhomogeneous cosmological metrics with open and closed spatial geometries. The late time acceleration is present due to effective cosmological terms induced by nonlinear off-diagonal interactions and graviton mass. The off-diagonal cosmological metrics and related Stückelberg fields are constructed in explicit form up to nonholonomic frame transforms of the Friedmann–Lamaître–Robertson–Walker (FLRW coordinates. We show that the solutions include matter, graviton mass and other effective sources modeling nonlinear gravitational and matter fields interactions in modified and/or massive gravity, with polarization of physical constants and deformations of metrics, which may explain certain dark energy and dark matter effects. There are stated and analyzed the conditions when such configurations mimic interesting solutions in general relativity and modifications and recast the general Painlevé–Gullstrand and FLRW metrics. Finally, we elaborate on a reconstruction procedure for a subclass of off-diagonal cosmological solutions which describe cyclic and ekpyrotic universes, with an emphasis on open issues and observable signatures.
Off-diagonal ekpyrotic scenarios and equivalence of modified, massive and/or Einstein gravity
Energy Technology Data Exchange (ETDEWEB)
Vacaru, Sergiu I., E-mail: sergiu.vacaru@uaic.ro [University “Al. I. Cuza” Iaşi, Rector' s Department, 14 Alexandru Lapuşneanu Street, Corpus R, UAIC, Office 323, Iaşi, 700057 (Romania); Max-Planck-Institute for Physics, Werner-Heisenberg-Institute, Foehringer Ring 6, München, D-80805 (Germany); Riemann Center for Geometry and Physics, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover (Germany)
2016-01-10
Using our anholonomic frame deformation method, we show how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates and undergoing a phase of ultra-slow contraction can be constructed in massive gravity. In this paper, there are found and studied new classes of locally anisotropic and (in)homogeneous cosmological metrics with open and closed spatial geometries. The late time acceleration is present due to effective cosmological terms induced by nonlinear off-diagonal interactions and graviton mass. The off-diagonal cosmological metrics and related Stückelberg fields are constructed in explicit form up to nonholonomic frame transforms of the Friedmann–Lamaître–Robertson–Walker (FLRW) coordinates. We show that the solutions include matter, graviton mass and other effective sources modeling nonlinear gravitational and matter fields interactions in modified and/or massive gravity, with polarization of physical constants and deformations of metrics, which may explain certain dark energy and dark matter effects. There are stated and analyzed the conditions when such configurations mimic interesting solutions in general relativity and modifications and recast the general Painlevé–Gullstrand and FLRW metrics. Finally, we elaborate on a reconstruction procedure for a subclass of off-diagonal cosmological solutions which describe cyclic and ekpyrotic universes, with an emphasis on open issues and observable signatures.
On Exact Solutions and the Consistency of 3D Minimal Massive Gravity
Altas, Emel
2015-01-01
We show that all algebraic Type-O, Type-N and Type-D and some Kundt-Type solutions of Topologically Massive Gravity are inherited by its holographically well-defined deformation, that is the recently found Minimal Massive Gravity. This construction provides a large class of constant scalar curvature solutions to the theory. We also study the consistency of the field equations both in the source-free and matter-coupled cases. Since the field equations of MMG do not come from a Lagrangian that depends on the metric and its derivatives only, it lacks the Bianchi identity valid for all non-singular metrics. But it turns out that for the solutions of the equations, Bianchi identity is satisfied. This is a necessary condition for the consistency of the classical field equations but not a sufficient one, since the the rank-two tensor equations are susceptible to double-divergence. We show that for the source-free case the double-divergence of the field equations vanish for the solutions. In the matter-coupled case, ...
Hendi, S. H.; Eslam Panah, B.; Panahiyan, S.
2017-06-01
Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
GRAVITY Spectro-interferometric Study of the Massive Multiple Stellar System HD 93206 A
Sanchez-Bermudez, J.; Alberdi, A.; Barbá, R.; Bestenlehner, J. M.; Cantalloube, F.; Brandner, W.; Henning, Th.; Hummel, C. A.; Maíz Apellániz, J.; Pott, J.-U.; Schödel, R.; van Boekel, R.
2017-08-01
Characterization of the dynamics of massive star systems and the astrophysical properties of the interacting components are a prerequisite for understanding their formation and evolution. Optical interferometry at milliarcsecond resolution is a key observing technique for resolving high-mass multiple compact systems. Here, we report on Very Large Telescope Interferometer/GRAVITY, Magellan/Folded-port InfraRed Echellette, and MPG2.2 m/FEROS observations of the late-O/early-B type system HD 93206 A, which is a member of the massive cluster Collinder 228 in the Carina nebula complex. With a total mass of about 90 {M}⊙ , it is one of the most compact massive quadruple systems known. In addition to measuring the separation and position angle of the outer binary Aa-Ac, we observe Brγ and He i variability in phase with the orbital motion of the two inner binaries. From the differential phase ({{{Δ }}}φ ) analysis, we conclude that the Brγ emission arises from the interaction regions within the components of the individual binaries, which is consistent with previous models for the X-ray emission of the system based on wind-wind interaction. With an average 3σ deviation of {{{Δ }}}φ ˜ 15^\\circ , we establish an upper limit of p ˜ 0.157 mas (0.35 au) for the size of the Brγ line-emitting region. Future interferometric observations with GRAVITY using the 8 m Unit Telescopes will allow us to constrain the line-emitting regions down to angular sizes of 20 μas (0.05 au at the distance of the Carina nebula).
Can Massive Gravity Explain the Mass Discrepancy - Acceleration Relation of Disk Galaxies?
Trippe, Sascha
2013-01-01
The empirical mass discrepancy-acceleration (MDA) relation of disk galaxies provides a key test for models of galactic dynamics. In terms of modified laws of gravity and/or inertia, the MDA relation quantifies the transition from Newtonian to modified dynamics at low centripetal accelerations a_c < 10^-10 m/s^2. As yet, neither dynamical models based on dark matter nor proposed modifications of the laws of gravity/inertia have predicted the functional form of the MDA relation. In this work, I revisit the MDA data and compare them to four different theoretical scaling laws. Three of these scaling laws are entirely empirical, the fourth one - the "simple mu" function of Modified Newtonian Dynamics - derives from a toy model of gravity based on massive gravitons (the "graviton picture"). All theoretical MDA relations comprise one free parameter of the dimension of an acceleration, Milgrom's constant a_M. I find that the "simple mu" function provides a good fit to the data free of notable systematic residuals ...
Setare, M R
2016-01-01
We consider the Generalized Minimal Massive Gravity (GMMG) model in the first order formalism. We show that all the solutions of the Einstein gravity with negative cosmological constants solve the equations of motion of considered model. Then we find an expression for the off-shell conserved charges of this model. By considering the near horizon geometry of a three dimensional black hole in the Gaussian null coordinates, we find near horizon conserved charges and their algebra. The obtained algebra is centrally extended. By writing the algebra of conserved charges in terms of Fourier modes and considering the BTZ black hole solution as an example, one can see that the charge associated with rotations along $\\mathcal{Y}_{0}$ coincides exactly with the angular momentum, and he charge associated with time translations $\\mathcal{T}_{0}$ is the product of the black hole entropy and its temperature. As we expect, in the limit when the GMMG tends to the Einstein gravity, all the result we obtain in this paper reduce...
Prasia, P
2016-01-01
In this work we study the Quasi Normal Modes(QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter((A)dS) space time. It is found that the behavior of QNMs changes with the massive parameter and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter and also on the charge of the black hole.
On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity
Huang, Qing-Guo; Xing, Yu-Hang; Zhang, Ke-Chao; Zhou, Shuang-Yong
2015-01-01
In de Rham-Gabadadze-Tolley (dRGT) massive gravity and bigravity, a non-minimal matter coupling involving both metrics generically re-introduces the Boulware--Deser (BD) ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, absence of Ostrogradski ghosts in the decoupling limit and absence of the BD ghost from matter quantum loop corrections.
On the Faddeev-Jackiw symplectic framework for topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Escalante, Alberto [Benemerita Universidad Autonoma de Puebla, Instituto de Fisica, Puebla (Mexico); Rodriguez-Tzompantzi, Omar [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Fisico Matematicas, Puebla (Mexico)
2016-10-15
The dynamical structure of topologically massive gravity in the context of the Faddeev-Jackiw symplectic approach is studied. It is shown that this method allows us to avoid some ambiguities arising in the study of the gauge structure via the Dirac formalism. In particular, the complete set of constraints and the generators of the gauge symmetry of the theory are obtained straightforwardly via the zero modes of the symplectic matrix. In order to obtain the generalized Faddeev-Jackiw brackets and calculate the local physical degrees of freedom of this model, an appropriate gauge-fixing procedure is introduced. Finally, the similarities and relative advantages between the Faddeev-Jackiw method and Dirac's formalism are briefly discussed. (orig.)
On the Faddeev-Jackiw Symplectic Framework for Topologically Massive Gravity
Escalante, Alberto
2016-01-01
The dynamical structure of topologically massive gravity in the context of the Faddeev-Jackiw approach is studied. We present a detailed analysis of the constraints and we show that this formalism is equivalent and more economical than Dirac's method. In particular, we identify the complete set of constraints of the theory, from which the number of physical degrees of freedom is explicitly computed. Furthermore, in order to obtain all the generalized Faddeev-Jackiw brackets an appropriate gauge-fixing procedure is introduced and we prove that the generalized Faddeev-Jackiw brackets and the Dirac ones coincide to each other. Finally, the similarities and advantages between Faddeev-Jackiw method and Dirac's formalism are discussed.
Towards the uniqueness of Lifshitz black holes and solitons in New Massive Gravity
Ayón-Beato, Eloy; Juárez-Aubry, María Montserrat
2014-01-01
We prove that the z=1 and z=3 Lifshitz black hole solutions of New Massive Gravity in three dimensions are the only static axisymmetric solutions that can be cast in a Kerr-Schild form with a seed metric given by the Lifshitz spacetime. Correspondingly, we study the issue of uniqueness of Lifshitz solitons when considering an ansatz involving a single metric function. We show this problem can be mapped to the previous one and that the z=1 and z=1/3 Lifshitz soliton solutions are the only ones within this class. Finally, our approach suggests for the first time an explanation as to what is special about those particular values of the dynamical critical exponent z at finite temperature.
Massive torsion modes, chiral gravity and the Adler–Bell–Jackiw anomaly
Chang, L N; Chang, Lay Nam; Soo, Chopin
2003-01-01
Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-tranverse vacuum polarization tensors, and become massive as a result of the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin 1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful.
Massive torsion modes, chiral gravity, and the Adler-Bell-Jackiw anomaly
Chang, L N; Chang, Lay Nam; Soo, Chopin
2003-01-01
Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin 1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter...
Gordon and Kerr-Schild ansatze in massive and bimetric gravity
Baccetti, Valentina; Visser, Matt
2012-01-01
We develop the "generalized Gordon ansatz" for the ghost-free versions of both massive and bimetric gravity, an ansatz which is general enough to include almost all spacetimes commonly considered to be physically interesting, and restricted enough to greatly simplify calculations. The ansatz allows explicit calculation of the matrix square root gamma = sqrt{g^{-1} f} appearing as a central feature of the ghost-free analysis. In particular, this ansatz automatically allows us to write the effective stress-energy tensor as that corresponding to a perfect fluid. A qualitatively similar "generalized Kerr-Schild ansatz" can also be easily considered, now leading to an effective stress-energy tensor that corresponds to a null fluid. Cosmological implications are considered, as are consequences for black hole physics. Finally we have a few words to say concerning the null energy condition in the framework provided by these ansatze.
Is there vacuum when there is mass? Vacuum and non-vacuum solutions for massive gravity
Martin-Moruno, Prado
2013-01-01
Massive gravity is a theory which has a tremendous amount of freedom to describe different cosmologies; but at the same time the various solutions one encounters must fulfill some rather nontrivial constraints. Most of the freedom comes not from the Lagrangian, which contains only a small number of free parameters (typically 3 depending on counting conventions), but on the fact that one is in principle free to choose the background reference metric almost arbitrarily --- which effectively introduces a non-denumerable infinity of free parameters. In the current paper we stress that although changing the reference metric would lead to a different cosmological model, this does not mean that the dynamics of our own universe can be entirely divorced from its matter content. That is, while the choice of reference metric certainly influences the evolution of the physically observable foreground metric, the effect of matter cannot be neglected. Nevertheless, the relation between matter and geometry can be significant...
Self-accelerating Massive Gravity: Superluminality, Cauchy Surfaces and Strong Coupling
Motloch, Pavel; Joyce, Austin; Motohashi, Hayato
2015-01-01
Self-accelerating solutions in massive gravity provide explicit, calculable examples that exhibit the general interplay between superluminality, the well-posedness of the Cauchy problem, and strong coupling. For three particular classes of vacuum solutions, one of which is new to this work, we construct the conformal diagram for the characteristic surfaces on which isotropic stress-energy perturbations propagate. With one exception, all solutions necessarily possess spacelike characteristics, indicating perturbative superluminality. Foliating the spacetime with these surfaces gives a pathological frame where kinetic terms of the perturbations vanish, confusing the Hamiltonian counting of degrees of freedom. This frame dependence distinguishes the vanishing of kinetic terms from strong coupling of perturbations or an ill-posed Cauchy problem. We give examples where spacelike characteristics do and do not originate from a point where perturbation theory breaks down and where spacelike surfaces do or do not inte...
Massive torsion modes, chiral gravity and the Adler-Bell-Jackiw anomaly
Energy Technology Data Exchange (ETDEWEB)
Chang, Lay Nam [Department of Physics, Virginia Tech., Blacksburg, VA 24061-0435 (United States); Soo Chopin [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)
2003-04-07
Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin-1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition, it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter term which is the Samuel-Jacobson-Smolin action of chiral gravity in four dimensions.
Comment on ''Quantum massive conformal gravity'' by F.F. Faria
Energy Technology Data Exchange (ETDEWEB)
Myung, Yun Soo [Inje University, Institute of Basic Sciences and Department of Computer Simulation, Gimhae (Korea, Republic of)
2016-06-15
In a recent paper in EPJC doi:10.1140/epjc/s10052-016-4037-5, Faria has shown that quantum massive conformal gravity is renormalizable but has ghost states. We comment this paper on the aspect of renormalizability. (orig.)
Thermodynamics of the Apparent Horizon in FRW Universe with Massive Gravity
Institute of Scientific and Technical Information of China (English)
LI Hui; ZHANG Yi
2013-01-01
Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive gravity model in cosmology proposed lately,the corrected entropic formula of the apparent horizon is obtained with the help of the modified Friedmann equations.This entropy-area relation,together with the identified Misner-Sharp internal energy,verifies the first law of thermodynamics for the apparent horizon with a volume change term for consistency.On the other hand,by means of the corrected entropy-area formula and the Clausius relation δQ =T dS,where the heat flow δQ is the energy-supply of pure matter projecting on the vector ξ tangent to the apparent horizon and should be looked on as the amount of energy crossing the apparent horizon during the time interval dt and the temperature of the apparent horizon for energy crossing during the same interval is 1/(2π(r)A),the modified Friedmann equations governing the dynamical evolution of the universe are reproduced with the known energy density and pressure of massive graviton.The integration constant is found to correspond to a cosmological term which could be absorbed into the energy density of matter.Having established the correspondence of massive cosmology with the unified first law of thermodynamics on the apparent horizon,the validity of the generalized second law of thermodynamics is also discussed by assuming the thermal equilibrium between the apparent horizon and the matter field bounded by the apparent horizon.It is found that,in the limit Hc → 0,which recovers the Minkowski reference metric solution in the flat case,the generalized second law of thermodynamics holds if α3 + 4α4 ＜ 0.Without this condition,even for the simplest model of dRGT massive cosmology with α3 =α4 =0,the generalized second law of thermodynamics could be violated.
Pitts, J Brian
2015-01-01
Klein-Gordon gravity, 1920s-30s particle physics, and 1890s Neumann-Seeliger modified gravity suggest a "graviton mass term" *algebraic* in the potential. Unlike Nordstr\\"om's "massless" theory, massive scalar gravity is invariant under the Poincar\\'e group but not the 15-parameter conformal group. It thus exhibits the whole Minkowski space-time structure, indirectly for volumes. Massive scalar gravity is plausible as a field theory, but violates Einstein's principles of general covariance, general relativity, equivalence, and Mach. Geometry is a poor guide: matter sees a conformally flat metric due to universal coupling, but gravity sees the rest of the flat metric (on long distances) in the mass term. What is the `true' geometry, in line with Poincar\\'e's modal conventionality argument? Infinitely many theories exhibit this bimetric `geometry,' all with the total stress-energy's trace as source; geometry does not explain the field equations. The irrelevance of the Ehlers-Pirani-Schild construction to conven...
Low-energy effects in a higher-derivative gravity model with real and complex massive poles
Accioly, Antonio; Shapiro, Ilya L
2016-01-01
The most simple super-renormalizable model of quantum gravity is based on the general local covariant six-derivative action. It was recently shown that such a theory may also have unitary S-matrix, in the case when massive poles are complex. In the present work we construct the modified Newton potential and explore the gravitational light bending in a general six-derivative theory, including the most interesting case of complex massive poles. In what concerns light deflection, the results are obtained within classical and semiclassical approaches. The presentation is given in details which can be useful for better understanding the effects of the higher derivative terms.
Reentrant phase transitions of higher-dimensional AdS black holes in dRGT massive gravity
Energy Technology Data Exchange (ETDEWEB)
Zou, De-Cheng; Yue, Ruihong [Yangzhou University, College of Physical Science and Technology, Yangzhou (China); Zhang, Ming [Xi' an Aeronautical University, Faculty of Science, Xi' an (China)
2017-04-15
We study the P-V criticality and phase transition in the extended phase space of anti-de Sitter (AdS) black holes in higher-dimensional de Rham, Gabadadze and Tolley (dRGT) massive gravity, treating the cosmological constant as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Besides the usual small/large black hole phase transitions, the interesting thermodynamic phenomena of reentrant phase transitions (RPTs) are observed for black holes in all d ≥ 6-dimensional spacetime when the coupling coefficients c{sub i}m{sup 2} of massive potential satisfy some certain conditions. (orig.)
arXiv Failures of homogeneous and isotropic cosmologies in Extended Quasi-Dilaton Massive Gravity
Anselmi, Stefano; López Nacir, Diana; Starkman, Glenn D.
2017-10-03
We analyze the Extended Quasi-Dilaton Massive Gravity model around a Friedmann-Lema\\^itre-Robertson-Walker cosmological background. We present a careful stability analysis of asymptotic fixed points. We find that the traditional fixed point cannot be approached dynamically, except from a perfectly fine-tuned initial condition involving both the quasi-dilaton and the Hubble parameter. A less-well examined fixed-point solution, where the time derivative of the 0-th St\\"uckelberg field vanishes $\\dot\\phi^0=0$, encounters no such difficulty, and the fixed point is an attractor in some finite region of initial conditions. We examine the question of the presence of a Boulware-Deser ghost in the theory. We show that the additional constraint which generically allows for the elimination of the Boulware-Deser mode is only present under special initial conditions. We find that the only possibility corresponds to the traditional fixed point and the initial conditions are the same fine-tuned conditions that allow the fix...
Gravitational radiation from compact binary systems in the massive Brans-Dicke theory of gravity
Alsing, Justin; Will, Clifford; Zaglauer, Helmut
2011-01-01
We derive the equations of motion, the periastron shift, and the gravitational radiation damping for quasicircular compact binaries in a massive variant of the Brans-Dicke theory of gravity. We also study the Shapiro time delay and the Nordtvedt effect in this theory. By comparing with recent observational data, we put bounds on the two parameters of the theory: the Brans-Dicke coupling parameter \\omega_{BD} and the scalar mass m_s. We find that the most stringent bounds come from Cassini measurements of the Shapiro time delay in the Solar System, that yield a lower bound \\omega_{BD}>40000 for scalar masses m_s1000 for m_s1250 for m_s<10^{-20} eV. A first estimate suggests that bounds comparable to the Shapiro time delay may come from observations of radiation damping in the eccentric white dwarf-neutron star binary PSR J1141-6545, but a quantitative prediction requires the extension of our work to eccentric orbits.
Gravity as the main driver of non-thermal motions in massive star formation
Traficante, A; Smith, R; Billot, N; Duarte-Cabral, A; Peretto, N; Molinari, S; Pineda, J E
2015-01-01
The origin of non-thermal motions in massive star forming regions can be ascribed to turbulence acting against the gravitational collapse, or to the self-gravity itself driving the rapid global collapse. The dependence between velocity dispersion, radius and clouds surface density found by Heyer et al. (2009), $\\sigma/R^{1/2}\\propto \\Sigma^{1/2}$, has been interpreted in terms of global collapse of clouds. In this work we demonstrate that this relation is an expression of a more general relation between accelerations. We introduce the gravo-turbulent acceleration, a$_k$, which describe the non-thermal motions in each region, and the acceleration generated by the gravitational field a$_G$, which is proportional to $\\Sigma$. We also introduce a new coefficient, the force partition coefficient $\\alpha_{for}$ which is equivalent to the virial parameter but does not distinguish between collapsing and non-collapsing regions. In this work we use the a$_k$ - a$_G$ formalism in the analysis of a new sample of 16 massi...
de Rham-Gabadadze-Tolley massive gravity with degenerate reference metrics
Cao, Li-Ming; Peng, Yuxuan; Zhang, Yun-Long
2016-06-01
In De Rham-Gabadadze-Tolley massive gravity, to get the equations of motion, the square root tensor is assumed to be invertible in the variation of the action. However, this condition cannot be fulfilled when the reference metric is degenerate. This implies that the resulting equations of motion might be different from the case where the reference metric has full rank. In this paper, by generalizing the Moore-Penrose inverse to the cases of symmetric tensors on Lorentz manifolds, we get the equations of motion of the theory with a degenerate reference metric. It is found that the equations of motion are a little bit different from those in the nondegenerate cases. Based on the result of the equations of motion, for the (2 +n )-dimensional solutions with the symmetry of n -dimensional maximally symmetric space, we prove a generalized Birkhoff-type theorem in the case where the degenerate reference metric has rank n ; i.e., we show that the solutions must be Schwarzschild type or Nariai-Bertotti-Robinson type under the given assumptions.
Open FRW universes and self-acceleration from nonlinear massive gravity
Gumrukcuoglu, A Emir; Mukohyama, Shinji
2011-01-01
In the context of a recently proposed nonlinear massive gravity with Lorentz-invariant mass terms, we investigate open Friedmann-Robertson-Walker (FRW) universes driven by arbitrary matter source. While the flat FRW solutions were recently shown to be absent, the proof does not extend to the open universes. We find three independent branches of solutions to the equations of motion for the St\\"uckelberg scalars. One of the branches does not allow any nontrivial FRW cosmologies, as in the previous no-go result. On the other hand, both of the other two branches allow general open FRW universes governed by the Friedmann equation with the matter source, the standard curvature term and an effective cosmological constant $\\Lambda_{\\pm}=c_{\\pm}m_g^2$. Here, $m_g$ is the graviton mass, +and - represent the two branches, and $c_{\\pm}$ are constants determined by the two dimensionless parameters of the theory. Since an open FRW universe with a sufficiently small curvature constant can approximate a flat FRW universe but...
Cosmological perturbations and observational constraints on non-local massive gravity
Nesseris, Savvas
2014-01-01
Non-local massive gravity can provide an interesting explanation for the late-time cosmic acceleration, with a dark energy equation of state $w_{\\rm DE}$ smaller than $-1$ in the past. We derive the equations of linear cosmological perturbations to confront such models with the observations of large-scale structures. The effective gravitational coupling to non-relativistic matter associated with galaxy clusterings is close to the Newton's gravitational constant $G$ for a mass scale $m$ slightly smaller than the today's Hubble parameter $H_0$. Taking into account the background expansion history as well as the evolution of matter perturbations $\\delta_m$, we test for these models with the Type Ia Supernovae (SnIa) from the Union 2.1, the Cosmic Microwave Background (CMB) measurements from Planck, a collection of baryon acoustic oscillations (BAO), and the growth rate data of $\\delta_m$. Using a higher value of $H_0$ derived from its direct measurement ($H_0 \\gtrsim 70$ km s$^{-1}$ Mpc$^{-1}$) the data strongly...
Slow-roll inflation from massive vector fields non-minimally coupled to gravity
Oliveros, A.
2017-01-01
In this work we study slow-roll inflation for a vector-tensor model with massive vector fields non-minimally coupled to gravity. The model under consideration has arbitrary parameters for each geometrical coupling. Taking into account a spatially flat FRW type universe and a general vector fields (with temporal and spatial components), we get the general expressions for equation of motion and the total energy momentum tensor. In this scenario, the isotropy of expansion is guaranteed considering a triplet of orthogonal vector fields, but the effective mass of the vector field is of the order of the Hubble scale and the inflationary regime is difficult to realize with this model. However, for suitable values (or constraints) of model parameters, it is possible to overcome this issue. In this sense, two cases were analyzed. In the first case, a regime with slow-roll inflation was obtained, and for the second case the vector field behaves as a constant, and it drives a quasi de Sitter expansion, hence that slow-roll takes place and inflation occurs.
Self-accelerating Massive Gravity: How Zweibeins Walk through Determinant Singularities
Gratia, Pierre; Wyman, Mark
2013-01-01
The theory of massive gravity possesses ambiguities when the spacetime metric evolves far from the non-dynamical fiducial metric used to define it. We explicitly construct a spherically symmetric example case where the metric evolves to a coordinate-independent determinant singularity which does not exist in the initial conditions. Both the metric and the vierbein formulation of the theory are ill-defined at this point. In unitary gauge, the chart of the spacetime ends at this point and does not cover the full spacetime whereas the spherically symmetric vierbeins, or zweibeins, of the fiducial metric become non-invertible and do not describe a valid metric. Nonetheless it is possible to continuously join a zweibein solution on the other side of the singularity which picks one of the degenerate solutions of the metric square root. This continuous solution is not the choice conventionally made in the previous literature. We also show that the Stueckelberg equations of motion on the self-accelerating branch prev...
Tkachenko, A; Pavlovski, K; Southworth, J; Degroote, P; Debosscher, J; Still, M; Bryson, S; Molenberghs, G; Bloemen, S; de Vries, B L; Hrudkova, M; Lombaert, R; Neyskens, P; Papics, P I; Raskin, G; Van Winckel, H; Morris, R L; Sanderfer, D T; Seader, S E
2012-01-01
We report the discovery of low-amplitude gravity-mode oscillations in the massive binary star V380 Cyg, from 180 d of Kepler custom-aperture space photometry and 5 months of high-resolution high signal-to-noise spectroscopy. The new data are of unprecedented quality and allowed to improve the orbital and fundamental parameters for this binary. The orbital solution was subtracted from the photometric data and led to the detection of periodic intrinsic variability with frequencies of which some are multiples of the orbital frequency and others are not. Spectral disentangling allowed the detection of line-profile variability in the primary. With our discovery of intrinsic variability interpreted as gravity mode oscillations, V380 Cyg becomes an important laboratory for future seismic tuning of the near-core physics in massive B-type stars.
DEFF Research Database (Denmark)
Würtzen, G.; Olsen, P.
1986-01-01
Groups of 40, 29, 39 and 44 F0 rats of each sex were fed a semi-synthetic diet containing butylated hydroxytoluene (BHT) in concentrations to provide intakes of 0, 25, 100 or 500 mg/kg body weight/day, respectively. The F0 rats were mated, and groups of 100, 80, 80 and 100 F1 rats of each sex were...... formed. After weaning, the highest dose of BHT was lowered to 250 mg/kg/day for the F1 rats. At weaning the BHT-treated F1 rats, especially the males, had lower body weights than the controls and the effect was dose related. The survival of the BHT-treated rats of both sexes was higher than...
Meng, K.; Li, J.
2016-10-01
We construct a new static black hole solution of Gauss-Bonnet massive gravity coupled to Maxwell and Yang-Mills fields in five dimensions. We calculate the thermodynamical quantities of the black hole and check the first law of black hole thermodynamics. Thermal stability of the black hole is explored in the context of both canonical and grand canonical ensembles. By identifying the cosmological constant as the pressure of the gravitational system, we study the phase transitions of the black hole.
Energy Technology Data Exchange (ETDEWEB)
Prasia, P.; Kuriakose, V.C. [Cochin University of Science and Technology, Department of Physics, Kochi (India)
2017-01-15
In this work we study the Quasi-Normal Modes (QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter ((A)dS) space-time. It is found that the behavior of QNMs changes with the massive parameter of the graviton and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space-time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter of the graviton and also on the charge of the black hole. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Garbarz, Alan, E-mail: alan-at@df.uba.ar [Departamento de Física, Universidad de Buenos Aires FCEN-UBA, IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires, Argentina and Instituto de Física de La Plata, Universidad Nacional de La Plata IFLP-UNLP, C.C. 67 (Argentina); Giribet, Gaston, E-mail: gaston-at@df.uba.ar, E-mail: af.goya-at@df.uba.ar; Goya, Andrés, E-mail: gaston-at@df.uba.ar, E-mail: af.goya-at@df.uba.ar [Departamento de Física, Universidad de Buenos Aires FCEN-UBA, IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Leston, Mauricio, E-mail: mauricio-at@iafe.uba.ar [Instituto de Astronomía y Física del Espacio IAFE-CONICET, Ciudad Universitaria, C.C. 67 Suc. 28, 1428, Buenos Aires (Argentina)
2015-03-26
We consider critical gravity in three dimensions; that is, the New Massive Gravity theory formulated about Anti-de Sitter (AdS) space with the specific value of the graviton mass for which it results dual to a two-dimensional conformai field theory with vanishing central charge. As it happens with Kerr black holes in four-dimensional critical gravity, in three-dimensional critical gravity the Bañados-Teitelboim-Zanelli black holes have vanishing mass and vanishing angular momentum. However, provided suitable asymptotic conditions are chosen, the theory may also admit solutions carrying non-vanishing charges. Here, we give simple examples of exact solutions that exhibit falling-off conditions that are even weaker than those of the so-called Log-gravity. For such solutions, we define the quasilocal stress-tensor and use it to compute conserved charges. Despite the drastic deformation of AdS{sub 3} asymptotic, these solutions have finite mass and angular momentum, which are shown to be non-zero.
An improved financial tool to replace BHT
2002-01-01
In November, the BHT tool used to control financial data will be replaced by an improved and more powerful system, called CET for CERN Expenditure Tracking. The team in charge of CET. From left to right, sitting, Martyn Rankin, David McGlashan, standing, Per Gunnar Jonsson, James Purvis and Mikael Angberg. After 10 years of BHT at CERN, in order to face the challenges of the LHC era, and following the recommendations of the External Review Committee, the BHT application will be replaced by an improved and more powerful expenditure tracking tool called CET for CERN Expenditure Tracking. For those who are not familiar with it, the BHT, Budget Holders Toolkit, is a utility that provides a way to view CERN financial data. It is available for users who have access to at least one budget code. The new CET represents a tool that not only allows powerful analysis of the past, but also assists in forecasting the future. CET will offer significantly more functionality than BHT, including extended contract analysis, ...
Strong Gravitational Lensing as a Probe of Gravity, Dark-Matter and Super-Massive Black Holes
Koopmans, L V E; Barnabe, M; Bolton, A; Bradac, M; Ciotti, L; Congdon, A; Czoske, O; Dye, S; Dutton, A; Elliasdottir, A; Evans, E; Fassnacht, C D; Jackson, N; Keeton, C; Lazio, J; Marshall, P; Meneghetti, M; McKean, J; Moustakas, L; Myers, S; Nipoti, C; Suyu, S; van de Ven, G; Vegetti, S; Wambsganss, J; Webster, R; Wucknitz, O; Zhao, H-S
2009-01-01
Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and (metric) theories of gravity, is still ill-defined. Strong gravitational lensing furnishes a powerful method to probe gravity in the central regions of galaxies. It can (1) provide a unique detection-channel of dark-matter substructure beyond the local galaxy group, (2) constrain dark-matter physics, complementary to direct-detection experiments, as well as metric theories of gravity, (3) probe central super-massive black holes, and (4) provide crucial insight into galaxy formation processes from the dark matter point of view, independently of the nature and state of dark matter. To seriously address the above questions, a considerable increase in the number of strong gravitational-lens systems is required. In the timeframe 2010-2020, a staged approach with radio (e.g. EVLA, e-MERLIN, LOFAR, SKA phase-I) and optica...
Monitoring of BHT-quinone and BHT-CHO in the gas of capsules of Asclepias physocarpa.
Ma, Bing-Ji; Peng, Hua; Liu, Ji-Kai
2006-01-01
Three volatile components, namely benzoic acid ethyl ester (1), 2,6-di-tert-butyl-p-benzoquinone (BHT-quinone) (2), and 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO) (3), were detected from the gas in the capsules of Asclepias physocarpa by means of GC/MS analysis. BHT-quinone and BHT-CHO as organic pollutants are the degradation products of the antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). Ground water, lake water and/or rain water are a source of BHT metabolites in the plant Asclepias physocarpa.
Final report on the safety assessment of BHT(1).
Lanigan, Rebecca S; Yamarik, Torill A
2002-01-01
BHT is the recognized name in the cosmetics industry for butylated hydroxytoluene. BHT is used in a wide range of cosmetic formulations as an antioxidant at concentrations from 0.0002% to 0.5%. BHT does penetrate the skin, but the relatively low amount absorbed remains primarily in the skin. Oral studies demonstrate that BHT is metabolized. The major metabolites appear as the carboxylic acid of BHT and its glucuronide in urine. At acute doses of 0.5 to 1.0 g/kg, some renal and hepatic damage was seen in male rats. Short-term repeated exposure to comparable doses produced hepatic toxic effects in male and female rats. Subchronic feeding and intraperitoneal studies in rats with BHT at lower doses produced increased liver weight, and decreased activity of several hepatic enzymes. In addition to liver and kidney effects, BHT applied to the skin was associated with toxic effects in lung tissue. BHT was not a reproductive or developmental toxin in animals. BHT has been found to enhance and to inhibit the humoral immune response in animals. BHT itself was not generally considered genotoxic, although it did modify the genotoxicity of other agents. BHT has been associated with hepatocellular and pulmonary adenomas in animals, but was not considered carcinogenic and actually was associated with a decreased incidence of neoplasms. BHT has been shown to have tumor promotion effects, to be anticarcinogenic, and to have no effect on other carcinogenic agents, depending on the target organ, exposure parameters, the carcinogen, and the animal tested. Various mechanism studies suggested that BHT toxicity is related to an electrophillic metabolite. In a predictive clinical test, 100% BHT was a mild irritant and a moderate sensitizer. In provocative skin tests, BHT (in the 1% to 2% concentration range) produced positive reactions in a small number of patients. Clinical testing did not find any depigmentation associated with dermal exposure to BHT, although a few case reports of
Trajectory bending and gravitational lensing of massive particles in Schwarzschild gravity
Jia, Junji; Yang, Nan
2015-01-01
Both massless light ray and objects with nonzero mass experience trajectory bending in a gravitational field. In this work the bending of trajectories of massive objects in a Schwarzschild spacetime and the corresponding gravitational lensing effects are studied. A {\\it particle sphere} for Schwarzschild black hole (BH) is found with its radius a simple function of the particle velocity and proportional to the BH mass. A single master formula for both the massless and massive particle bending angle is found, in the form of an elliptic function depending on only the velocity and impact parameter measured in central mass. This bending angle is expanded in both large and small velocity limits and large and small impact parameter limits. The corresponding deflection angle for weak and strong gravitational lensing of massive particles are analyzed, and their corrections to the light ray deflection angles are obtained. The dependence of the deflection angles on the source angle and the particle speed is investigate...
Massive, massless and ghost modes of gravitational waves from higher-order gravity
DEFF Research Database (Denmark)
Bogdanos, Charalampos; Capozziello, Salvatore; De Laurentis, Mariafelicia
We linearize the field equations for higher order theories that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes with the latter being, in general, ghost modes. The...
Monitoring of the antioxidant BHT and its metabolite BHT-CHO in German river water and ground water.
Fries, Elke; Püttmann, Wilhelm
2004-02-05
The behavior of anthropogenic polar organic compounds in ground water during infiltration of river water to ground water was studied at the Oderbruch area on the eastern border of Germany. Additionally, waste water sewage treatment works (STWs) discharging their treated waste water into the Oder River and rain water precipitation from the Oderbruch area were investigated. The study was carried out from March 2000 to July 2001 to investigate seasonal variations of the target analytes. Samples were collected from four sites along the Oder River, from 24 ground water monitoring wells located close to the Oder, from one rain water collection station, from two roof runoffs, and from four STWs upstream of the Oderbruch. Results of the investigations of the antioxidant 3,5-di-tert-butyl-4-hydroxy-toluene (BHT) and its degradation product 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO) are presented. BHT and BHT-CHO were detected in all samples of the Oder River with mean concentrations of 178 and 102 ngl(-1), respectively. BHT and BHT-CHO were also detected in effluent waste water samples from municipal STWs at mean concentrations of 132 and 70 ngl(-1), respectively. Both compounds are discharged into river water directly via treated waste water. In the rain water sample, 308 ngl(-1) of BHT and 155 ngl(-1) of BHT-CHO were measured. Both compounds were detected in roof runoff with mean concentrations of 92 ngl(-1) for BHT and 138 ngl(-1) for BHT-CHO. The median values of BHT and BHT-CHO in ground water samples were 132 and 84 ngl(-1), respectively. The chemical composition of ground water from parts of the aquifer located less than 4.5 m distant from the river are greatly influenced by bank filtration. However, wet deposition followed by seepage of rain water into the aquifer is also a source of BHT and BHT-CHO in ground water.
Vacaru, Sergiu I
2015-01-01
We re-investigate how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates can be constructed in massive and f-modified gravity using the anholonomic frame deformation method. There are constructed new classes of locally anisotropic and (in) homogeneous cosmological metrics with open and closed spatial geometries. By resorting such solutions, we show that they describe the late time acceleration due to effective cosmological terms induced by nonlinear off-diagonal interactions, possible modifications of the gravitational action and graviton mass. The cosmological metrics and related St\\" uckelberg fields are constructed in explicit form up to nonholonomic frame transforms of the Friedmann-Lama\\^{\\i}tre-Robertson-Walker (FLRW) coordinates. The solutions include matter, graviton mass and other effective sources modelling nonlinear gravitational and matter fields interactions with polarization of physical constants and deformations of metrics, which may explain dark ene...
Matter Power Spectra in Viable $f(R)$ Gravity Models with Massive Neutrinos
Geng, Chao-Qiang; Shen, Jia-Liang
2015-01-01
We investigate the matter power spectra in the power law and exponential types of viable $f(R)$ theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, $\\Sigma m_{\
Garbarz, Alan; Vásquez, Yerko
2008-01-01
We study exact solutions to Cosmological Topologically Massive Gravity (CTMG) coupled to Topologically Massive Electrodynamics (TME) at special values of the coupling constants. For the particular case of the so called chiral point l\\mu_G=1, vacuum solutions (with vanishing gauge field) are exhibited. These correspond to a one-parameter deformation of GR solutions, and are continuously connected to the extremal Banados-Teitelboim-Zanelli black hole (BTZ) with bare constants J=-lM. In CTMG this extremal BTZ turns out to be massless, and thus it can be regarded as a kind of ground state. For certain range of parameters, our solution exhibits an event horizon located at finite geodesic distance. Although the solution is not asymptotically AdS_3 in the sense of Brown-Henneaux boundary conditions, it does obey the weakened asymptotic recently proposed by Grumiller and Johansson. Consequently, we discuss the computation of the conserved chages in terms of the stress-tensor in the boundary, and we find that the sign...
Light-Front Dynamics Of Massive Vector Chern-Simons Gravity
Aragone, C; Khoudeir, A
1993-01-01
We present a second order gravity action which consists of ordinary Einstein action augmented by a first-order, vector like, Chern-Simons quasi topological term. This theory is ghost-free and propagates a pure spin-2 mode. It is diffeomorphism invariant, although its local Lorentz invariance has been spontaneuosly broken. We perform the light-front (LF) analysis for both the linearized system and the exact curved model. In constrast to the 2+1 canonical analysis, in the quasi LF coordinates the differential constraints can be solved. Its solution is presented here.
To learn more about BHT replacement
2002-01-01
Following the article 'An improved financial tool to replace BHT' which appeared in Bulletin No 41/2002, dates of 4 general presentations were published. Please note that the time of the first presentation has changed from 16.00 hrs to 14.00 hrs. The dates/times are now as follows: Wednesday 16 October 14.00 hrs* IT Auditorium (English) *note change of time. Friday 18 October 16.00 hrs, SL Auditorium (French) Monday 21 October 10.00 hrs, LHC Auditorium (French) Wednesday 23 October 10.00 hrs, Council Chamber (English)
New perspective for black hole thermodynamics in Gauss-Bonnet-Born-Infeld massive gravity
Hendi, Seyed Hossein; Mo, Jie-Xiong; Panahiyan, Shahram; Panah, Behzad Eslam
2016-01-01
Following earlier study regarding Einstein-Gauss-Bonnet-massive black holes in the presence of Born-Infeld nonlinear electromagnetic field [S. H. Hendi, B. Eslam Panah and S. Panahiyan, arXiv:1510.00108], we study thermodynamical structure and critical behavior of these black holes through different methods in this paper. Geometrical thermodynamics is employed to give a picture regarding phase transition of these black holes. Next, a new method is used to derive critical pressure and horizon radius of these black holes. In addition, Maxwell equal area law is employed to study the Van der Waals like behavior of these black holes. Moreover, the critical exponents are calculated and by using Ehrenfest equations, the type of the phase transitions are determined.
New perspective for black hole thermodynamics in Gauss-Bonnet-Born-Infeld massive gravity
Energy Technology Data Exchange (ETDEWEB)
Hendi, Seyed Hossein [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM),Maragha (Iran, Islamic Republic of); Li, Gu-Qiang; Mo, Jie-Xiong [Lingnan Normal University, Institute of Theoretical Physics, Zhanjiang, Guangdong (China); Panahiyan, Shahram [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Panah, Behzad Eslam [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2016-10-15
Following an earlier study regarding Einstein-Gauss-Bonnet-massive black holes in the presence of a Born-Infeld nonlinear electromagnetic field (Hendi, arXiv:1510.00108, 2016), we study thermodynamical structure and critical behavior of these black holes through various methods in this paper. Geometrical thermodynamics is employed to give a picture regarding the phase transition of these black holes. Next, a new method is used to derive critical pressure and radius of the horizon of these black holes. In addition, Maxwell equal area law is employed to study the Van der Waals like behavior of these black holes. Moreover, the critical exponents are calculated and by using Ehrenfest equations, the type of phase transition is determined. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Lu, Jianbo; Wu, Yabo; Wang, Yan; Yang, Weiqiang [Liaoning Normal University, Department of Physics, Dalian (China); Liu, Molin [Xinyang Normal University, Department of Physics, Xinyang (China)
2016-12-15
Tensions between several cosmic observations were found recently, such as the inconsistent values of H{sub 0} (or σ{sub 8}) were indicated by the different cosmic observations. Introducing the massive neutrinos in ΛCDM could potentially solve the tensions. Viable f(R) gravity producing ΛCDM background expansion with massive neutrinos is investigated in this paper. We fit the current observational data: Planck-2015 CMB, RSD, BAO, and SNIa to constrain the mass of neutrinos in viable f(R) theory. The constraint results at 95% confidence level are: Σm{sub ν} < 0.202 eV for the active-neutrino case, m{sub ν,sterile}{sup eff} < 0.757 eV with N{sub eff} < 3.22 for the sterile neutrino case. For the effects due to the mass of the neutrinos, the constraint results on model parameter at 95% confidence level become f{sub R0} x 10{sup -6} > -1.89 and f{sub R0} x 10{sup -6} > -2.02 for two cases, respectively. It is also shown that the fitting values of several parameters much depend on the neutrino properties, such as the cold dark matter density, the cosmological quantities at matter-radiation equality, the neutrino density and the fraction of baryonic mass in helium. Finally, the constraint result shows that the tension between direct and CMB measurements of H{sub 0} gets slightly weaker in the viable f(R) model than that in the base ΛCDM model. (orig.)
Shear-free axial model in massive Brans-Dicke gravity
Sharif, M.; Manzoor, Rubab
2017-01-01
This paper explores the influences of dark energy on the shear-free axially symmetric evolution by considering self-interacting Brans-Dicke gravity as a dark energy candidate. We describe energy source of the model and derive all the effective dynamical variables as well as effective structure scalars. It is found that scalar field is one of the sources of anisotropy and dissipation. The resulting effective structure scalars help to study the dynamics associated with dark energy in any axial configuration. In order to investigate shear-free evolution, we formulate a set of governing equations along with heat transport equation. We discuss consequences of shear-free condition upon different SBD fluid models like dissipative non-geodesic and geodesic models. For dissipative non-geodesic case, the rotational distribution turns out to be the necessary and sufficient condition for radiating model. The dissipation depends upon inhomogeneous expansion. The geodesic model is found to be irrotational and non-radiating. The non-dissipative geodesic model leads to FRW model for positive values of the expansion parameter.
Shear-free axial model in massive Brans–Dicke gravity
Energy Technology Data Exchange (ETDEWEB)
Sharif, M., E-mail: msharif.math@pu.edu.pk [Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590 (Pakistan); Manzoor, Rubab, E-mail: rubab.manzoor@umt.edu.pk [Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590 (Pakistan); Department of Mathematics, University of Management and Technology, Johar Town Campus, Lahore-54782 (Pakistan)
2017-01-15
This paper explores the influences of dark energy on the shear-free axially symmetric evolution by considering self-interacting Brans–Dicke gravity as a dark energy candidate. We describe energy source of the model and derive all the effective dynamical variables as well as effective structure scalars. It is found that scalar field is one of the sources of anisotropy and dissipation. The resulting effective structure scalars help to study the dynamics associated with dark energy in any axial configuration. In order to investigate shear-free evolution, we formulate a set of governing equations along with heat transport equation. We discuss consequences of shear-free condition upon different SBD fluid models like dissipative non-geodesic and geodesic models. For dissipative non-geodesic case, the rotational distribution turns out to be the necessary and sufficient condition for radiating model. The dissipation depends upon inhomogeneous expansion. The geodesic model is found to be irrotational and non-radiating. The non-dissipative geodesic model leads to FRW model for positive values of the expansion parameter.
Matter power spectra in viable f(R gravity models with massive neutrinos
Directory of Open Access Journals (Sweden)
Chao-Qiang Geng
2015-01-01
Full Text Available We investigate the matter power spectra in the power law and exponential types of viable f(R theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, ∑mν, is allowed in the viable f(R models than that in the ΛCDM one. We obtain the constraints on the neutrino masses by using the CosmoMC package with the modified MGCAMB. Explicitly, we get ∑mν<0.451(0.214 eV at 95% C.L. in the Starobinsky (exponential model, while the corresponding one for the ΛCDM model is ∑mν<0.200 eV. Furthermore, by treating the effective number of neutrino species Neff as a free parameter along with ∑mν, we find that Neff=3.78−0.84+0.64(3.47−0.60+0.74 and ∑mν=0.533−0.411+0.254 (<0.386 eV at 95% C.L. in the Starobinsky (exponential model.
Matter power spectra in viable f(R) gravity models with massive neutrinos
Energy Technology Data Exchange (ETDEWEB)
Geng, Chao-Qiang, E-mail: geng@phys.nthu.edu.tw [Chongqing University of Posts and Telecommunications, Chongqing, 400065 (China); Department of Physics, National Tsing Hua University, Hsinchu, 300 Taiwan (China); National Center for Theoretical Sciences, Hsinchu, 300 Taiwan (China); Lee, Chung-Chi, E-mail: g9522545@oz.nthu.edu.tw [National Center for Theoretical Sciences, Hsinchu, 300 Taiwan (China); Shen, Jia-Liang, E-mail: dddirac@gmail.com [Department of Physics, National Tsing Hua University, Hsinchu, 300 Taiwan (China)
2015-01-05
We investigate the matter power spectra in the power law and exponential types of viable f(R) theories along with massive neutrinos. The enhancement of the matter power spectrum is found to be a generic feature in these models. In particular, we show that in the former type, such as the Starobinsky model, the spectrum is magnified much larger than the latter one, such as the exponential model. A greater scale of the total neutrino mass, ∑m{sub ν}, is allowed in the viable f(R) models than that in the ΛCDM one. We obtain the constraints on the neutrino masses by using the CosmoMC package with the modified MGCAMB. Explicitly, we get ∑m{sub ν}<0.451(0.214) eV at 95% C.L. in the Starobinsky (exponential) model, while the corresponding one for the ΛCDM model is ∑m{sub ν}<0.200 eV. Furthermore, by treating the effective number of neutrino species N{sub eff} as a free parameter along with ∑m{sub ν}, we find that N{sub eff}=3.78{sub −0.84}{sup +0.64}(3.47{sub −0.60}{sup +0.74}) and ∑m{sub ν}=0.533{sub −0.411}{sup +0.254}(<0.386) eV at 95% C.L. in the Starobinsky (exponential) model.
Gamow, George
2003-01-01
A distinguished physicist and teacher, George Gamow also possessed a special gift for making the intricacies of science accessible to a wide audience. In Gravity, he takes an enlightening look at three of the towering figures of science who unlocked many of the mysteries behind the laws of physics: Galileo, the first to take a close look at the process of free and restricted fall; Newton, originator of the concept of gravity as a universal force; and Einstein, who proposed that gravity is no more than the curvature of the four-dimensional space-time continuum.Graced with the author's own draw
Övgün, A.; Jusufi, Kimet
2017-07-01
This paper discusses the effects of the mass and angular momentum of massive vector and scalar particles on the Hawking temperature manifested under the effects of the generalized uncertainty principle (GUP). In particular, we calculate the Hawking temperature of a black hole in a warped DGP gravity model in the framework of the quantum tunneling method. We use the modified Proca and Klein-Gordon equations previously determined from the GUP Lagrangian in the spacetime background of a warped Dvali-Gabadadze-Porrati (DGP) metric, with the help of Hamilton-Jacobi (HJ) and semiclassical (WKB) approximation methods. We find that as a special case of a warped DGP black hole solution, the Hawking temperature of a Schwarzschild-de Sitter (SdS) black hole can be determined. Furthermore, the Hawking temperature is influenced by the mass and the angular momentum of vector and scalar particles and depends on which of those types of particles is being emitted by the black hole. We conclude that the nonthermal nature of the Hawking spectrum leads to Planck-scale nonthermal correlations, shedding light on the information paradox in black hole evaporation.
Energy Technology Data Exchange (ETDEWEB)
Setare, M R; Kamali, V, E-mail: rezakord@ipm.ir, E-mail: vkamali1362@gmail.com [Department of Science, Payame Noor University, Bijar (Iran, Islamic Republic of)
2011-11-07
We show that a BTZ black hole solution of cosmological topological massive gravity has a hidden conformal symmetry. In this regard, we consider the wave equation of a massless scalar field propagating in BTZ spacetime and find that the wave equation could be written in terms of the SL(2, R) quadratic Casimir. From the conformal coordinates, the temperatures of the dual conformal field theories (CFTs) could be read directly. Moreover, we compute the microscopic entropy of the dual CFT by the Cardy formula and find a perfect match to the Bekenstein-Hawking entropy of a BTZ black hole. Then, we consider Galilean conformal algebras (GCA), which arises as a contraction of relativistic conformal algebras (x {yields} {epsilon}x, t {yields} t, {epsilon} {yields} 0). We show that there is a correspondence between GCA{sub 2} on the boundary and contracted BTZ in the bulk. For this purpose we obtain the central charges and temperatures of GCA{sub 2}. Then, we compute the microscopic entropy of the GCA{sub 2} by the Cardy formula and find a perfect match to the Bekenstein-Hawking entropy of a BTZ black hole in a non-relativistic limit. The absorption cross section of a near-region scalar field also matches the microscopic absorption cross section of the dual GCA{sub 2}. So we find further evidence that shows correspondence between a contracted BTZ black hole and two-dimensional GCA.
Tkatchenko, A.; Aerts, C.; Pavlovski, K.; Southworth, J.; Degroote, P.; Debosscher, J.; Still, M.; Bryson, S; Molenberghs, Geert; Bloemen, S.; DeVries, B; Hrudkova, M.; Lombaert, R.; Neyskens, P.; Papics, P.
2012-01-01
We report the discovery of low-amplitude gravity-mode oscillations in the massive binary star V380 Cyg, from 180 d of Kepler custom-aperture space photometry and 5 months of highresolution high signal-to-noise ratio spectroscopy. The new data are of unprecedented quality and allowed the improvement of the orbital and fundamental parameters for this binary. The orbital solution was subtracted from the photometric data and led to the detection of periodic intrinsic variability with frequencies,...
Radical-scavenging activity of butylated hydroxytoluene (BHT) and its metabolites.
Fujisawa, Seiichiro; Kadoma, Yoshinori; Yokoe, Ichiro
2004-07-01
To clarify the radical-scavenging activity of butylated hydroxytoluene (BHT), a food additive, stoichiometric factors (n) and inhibition rate constants (kinh) were determined for 2,6-di-tert-butyl-4-methylphenol (BHT) and its metabolites 2,6-di-tert-butyl-p-benzoquinone (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHA-CHO) and 3,5-di-tert-butyl-4-hydroperoxy-4-methyl-2,5-cyclohexadiene-1-one (BHT-OOH). Values of n and kinh were determined from differential scanning calorimetry (DSC) monitoring of the polymerization of methyl methacrylate (MMA) initiated by 2,2'-azobis(isobutyronitrile) (AIBN) or benzoyl peroxide (BPO) at 70 degrees C in the presence or absence of antioxidants (BHT-related compounds). The n values declined in the order BHT (1-2) > BHT-CHO, BHT-OOH (0.1-0.3) > BHT-Q ( approximately 0). The n value for BHT with AIBN was approximately 1.0, suggesting dimerization of BHT. The kinh values declined in the order BHT-Q ((3.5-4.6) x 10(4) M(-1)s(-1)) > BHT-OOH (0.7-1.9 x 10(4) M(-1)s(-1)) > BHT-CHO ((0.4-1.7 x 10(4) M(-1)s(-1)) > BHT ((0.1-0.2 x 10(4) M(-1)s(-1)). The kinh for metabolites was greater than that for the parent BHT. Growing MMA radicals initiated by BPO were suppressed much more efficiently by BHT or BHT-Q compared with those initiated by AIBN. BHT was effective as a chain-breaking antioxidant.
Prasia, P
2016-01-01
We investigate black holes in a class of dRGT massive gravity for their quasi normal modes (QNMs) for neutral and charged ones using Improved Asymptotic Iteration Method (Improved AIM) and their thermodynamic behavior. The QNMs are studied for different values of the massive parameter m_g for both neutral and charged dRGT black holes under a massless scalar perturbation. As m_g increases, the magnitude of the quasi normal frequencies are found to be increasing. The results are also compared with the Schwarzchild de Sitter (SdS) case. P-V criticallity of the aforesaid black hoels under massles scalar perturbation in the de Sitter space are also studied in this paper. It is found that the thermodynamic behavior of a neutral black hole shows no physically feasible phase transition while a charged black hole shows a definite phase transition.
Prasia, P.; Kuriakose, V. C.
2016-07-01
We investigate black holes in a class of dRGT massive gravity for their quasi normal modes (QNMs) for neutral and charged ones using Improved Asymptotic Iteration Method and their thermodynamic behavior. The QNMs are studied for different values of the massive parameter m_g for both neutral and charged dRGT black holes under a massless scalar perturbation. As m_g increases, the magnitude of the quasi normal frequencies are found to be increasing. The results are also compared with the Schwarzchild de Sitter case. P-V criticallity of the aforesaid black hoels under massles scalar perturbation in the de Sitter space are also studied in this paper. It is found that the thermodynamic behavior of a neutral black hole shows no physically feasible phase transition while a charged black hole shows a definite phase transition.
Pitts, J Brian
2016-01-01
Classical and quantum field theory provide not only realistic examples of extant notions of empirical equivalence, but also new notions of empirical equivalence, both modal and occurrent. A simple but modern gravitational case goes back to the 1890s, but there has been apparently total neglect of the simplest relativistic analog, with the result that an erroneous claim has taken root that Special Relativity could not have accommodated gravity even if there were no bending of light. The fairly recent acceptance of nonzero neutrino masses shows that widely neglected possibilities for nonzero particle masses have sometimes been vindicated. In the electromagnetic case, there is permanent underdetermination at the classical and quantum levels between Maxwell's theory and the one-parameter family of Proca's electromagnetisms with massive photons, which approximate Maxwell's theory in the limit of zero photon mass. While Yang-Mills theories display similar approximate equivalence classically, quantization typically ...
Saito, Masatoshi; Sakagami, Hiroshi; Fujisawa, Seiichiro
2003-01-01
The cytotoxicity and apoptosis-inducing activity of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and 2-tert-butyl-4-methylphenol (BMP) and the mixture of BHA and BHT (BHA/BHT) (1:1, molar ratio) were investigated, using human promeylocytic leukemia cell lines (HL-60) and human squamous cell carcinoma cell lines (HSC-2). The 50% cytotoxic concentration (CC50) declined in the order of BHA, BHT (0.2-0.3 mM) > BHA/BHT (0.04-0.07 mM) > BMP (0.02-0.05 mM). The addition of antioxidants (N-acetyl-Lcysteine, sodium ascorbate, catalase) reduced the cytotoxicity of BHA/BHT or BMP against HSC-2 cells, but not that of BHA or BHT, whereas the addition of NADH, a quinone reductase to BMP, enhanced the cytotoxicity. These findings suggested that the cytotoxicity of BHA/BHT and BMP might be caused by reactive intermediates. BHA-induced cytotoxicity was enhanced by horseradish peroxidases, suggesting that BHA was oxidizable and produced cytotoxic BHA radicals. Internucleosomal DNA fragmentation of HL-60 cells was preferably induced by BHA/BHT and BMP, followed by BHA. The MnSOD mRNA expression in HL-60 cells assayed by reverse transcriptase-polymerase chain reaction was highly inhibited by BHA/BHT or BMP, accompanied by the change in the electrophoretic mobility of MnSOD on polyacryamide gel. These compounds activated caspase-3, 8 and 9 in HL-60 cells. Activations of caspases, particularly caspase-3, declined in the order of BHA/BHT > BHA > BMP > BHT. The most cytotoxic BMP activated caspase-3 activity to the least extent, possibly in part due to the occurrence of necrosis. The great cytotoxicity and apoptosis induction by BHA/BHT may be due to reactive intermediates derived from the interaction between BHA phenoxyl radical and BHT or BHT phenoxyl radical.
A new cubic theory of gravity in five dimensions: Black hole, Birkhoff's theorem and C-function
Oliva, Julio
2010-01-01
We present a new cubic theory of gravity in five dimensions which has second order traced field equations, analogous to BHT new massive gravity in three dimensions. Moreover, for static spherically symmetric spacetimes all the field equations are of second order, and the theory admits a new asymptotically locally flat black hole. Furthermore, we prove the uniqueness of this solution, study its thermodynamical properties, and show the existence of a C-function for the theory following the arguments of Anber and Kastor (arXiv:0802.1290 [hep-th]) in pure Lovelock theories. Finally, we include the Einstein-Gauss-Bonnet and cosmological terms and we find new asymptotically AdS black holes at the point where the three maximally symmetric solutions of the theory coincide. These black holes may also possess a Cauchy horizon.
Pitts, J Brian
2015-01-01
A massive relative of Einstein's theory was derived by universal coupling in the late 1960s by Freund, Maheshwari and Schonberg. In the last decade four $1$-parameter families of massive spin-$2$ theories (contravariant, covariant, tetrad, and cotetrad of almost any density weights) have been derived using universal coupling. The (co)tetrad derivations included 2 of the 3 pure spin-$2$ theories due to de Rham, Gabadadze, and Tolley; those two theories first appeared in the $2$-parameter Ogievetsky-Polubarinov family (1965), which developed the symmetric square root of the metric as a nonlinear group realization. One of the two theories was identified as pure spin-$2$ by Maheshwari in 1971-2, thus evading the Boulware-Deser-Tyutin-Fradkin ghost by the time it was announced---but with no impact. This paper permits nonlinear field redefinitions to build the effective metric. By not insisting in advance on knowing the observable significance of the graviton potential exactly to all orders, one finds that an \\emph...
Pathology of BHA- and BHT-induced lesions.
Moch, R W
1986-01-01
The pathology lesions from three studies, two with butylated hydroxyanisole (BHA) and one with butylated hydroxytoluene (BHT), are reviewed. When BHA was fed at 0.5 and 2.0% of the diet to F344 rats for two years, there was an increase in epithelial hyperplasia of the forestomach at both treatment levels. Papilloma and squamous-cell carcinoma of the forestomach were increased at the 2.0% level. When BHA was fed to beagle dogs at 1.0 and 1.3% of the diet for 180 days, no lesions/tumours of the distal oesophagus or stomach could be identified either at gross necropsy or by light or electron microscopy. The BHT was fed to Wistar rats at 0, 25, 100 and 250 mg/kg body weight. At the highest dose there was an increase in the number of rats with hepatocellular adenoma and with hepatocellular carcinoma.
Mohamed, Haby S.; Abdel Zaher, Mohamed; Senosy, Mahmoud M.; Saibi, Hakim; El Nouby, Mohamed; Fairhead, J. Derek
2015-06-01
The northern part of the Western Desert of Egypt represents the second most promising area of hydrocarbon potential after the Gulf of Suez province. An artificial neural network (ANN) approach was used to develop a new predictive model for calculation of the geothermal gradients in this region based on gravity and corrected bottom-hole temperature (BHT) data. The best training data set was obtained with an ANN architecture composed of seven neurons in the hidden layer, which made it possible to predict the geothermal gradient with satisfactory efficiency. The BHT records of 116 deep oil wells (2,000-4,500 m) were used to evaluate the geothermal resources in the northern Western Desert. Corrections were applied to the BHT data to obtain the true formation equilibrium temperatures, which can provide useful constraints on the subsurface thermal regime. On the basis of these corrected data, the thermal gradient was computed for the linear sections of the temperature-versus-depth data at each well. The calculated geothermal gradient using temperature log data was generally 30 °C/km, with a few local high geothermal gradients in the northwestern parts of the study area explained by potential local geothermal fields. The Bouguer gravity values from the study area ranged from -60 mGal in the southern parts to 120 mGal in the northern areas, and exhibited NE-SW and E-W trends associated with geological structures. Although the northern Western Desert of Egypt has low regional temperature gradients (30 °C/km), several potential local geothermal fields were found (>40 °C/km). The heat flow at each well was also computed by combining sets of temperature gradients and thermal conductivity data. Aerogravity data were used to delineate the subsurface structures and tectonic framework of the region. The result of this study is a new geothermal gradient map of the northern Western Desert developed from gravity and BHT log data.
Synthesis and antioxidant activity of [60]fullerene-BHT conjugates.
Enes, Roger F; Tomé, Augusto C; Cavaleiro, José A S; Amorati, Riccardo; Fumo, Maria Grazia; Pedulli, Gian Franco; Valgimigli, Luca
2006-06-02
Fullerene derivatives incorporating one or two 3,5-di-tert-butyl-4-hydroxyphenyl groups were synthesized by 1,3-dipolar cycloaddition of azomethine ylides to C(60). The O-H bond dissociation enthalpies (BDEs) of these compounds were estimated by studying, by means of EPR spectroscopy, the equilibration of each of these phenols and 2,6-di-tert-butyl-4-methylphenol (BHT) with the corresponding phenoxyl radicals. The antioxidant activity of the investigated phenols was also determined by measuring the rate constants for their reaction with peroxyl radicals in controlled autoxidation experiments and compared to that recorded under identical experimental settings for [60]fullerene itself and unlinked BHT. The results indicate that linking of the BHT structure to C(60) does not substantially alter the thermochemistry and kinetics of its reaction with peroxyl radicals, but such adducts may behave as interesting bimodal radical scavengers. The inherent rate constant for trapping of peroxyl radicals by C(60) per se (k(inh)=3.1+/-1.1 x 10(2) m(-1) s(-1)) indicates that, contrary to previous reports, [60]fullerene is an extremely weak chain-breaking antioxidant.
Energy Technology Data Exchange (ETDEWEB)
Pitts, J. Brian, E-mail: jbp25@cam.ac.uk
2016-02-15
Einstein’s equations were derived for a free massless spin-2 field using universal coupling in the 1950–1970s by various authors; total stress–energy including gravity’s served as a source for linear free field equations. A massive variant was likewise derived in the late 1960s by Freund, Maheshwari and Schonberg, and thought to be unique. How broad is universal coupling? In the last decade four 1-parameter families of massive spin-2 theories (contravariant, covariant, tetrad, and cotetrad of almost any density weights) have been derived using universal coupling. The (co)tetrad derivations included 2 of the 3 pure spin-2 theories due to de Rham, Gabadadze, and Tolley; those two theories first appeared in the 2-parameter Ogievetsky–Polubarinov family (1965), which developed the symmetric square root of the metric as a nonlinear group realization. One of the two theories was identified as pure spin-2 by Maheshwari in 1971–1972, thus evading the Boulware–Deser–Tyutin–Fradkin ghost by the time it was announced. Unlike the previous 4 families, this paper permits nonlinear field redefinitions to build the effective metric. By not insisting in advance on knowing the observable significance of the graviton potential to all orders, one finds that an arbitrary graviton mass term can be derived using universal coupling. The arbitrariness of a universally coupled mass/self-interaction term contrasts sharply with the uniqueness of the Einstein kinetic term. One might have hoped to use universal coupling as a tie-breaking criterion for choosing among theories that are equally satisfactory on more crucial grounds (such as lacking ghosts and having a smooth massless limit). But the ubiquity of universal coupling implies that the criterion does not favor any particular theories among those with the Einstein kinetic term.
Comparative metabolism, covalent binding and toxicity of BHT congeners in rat liver slices.
Reed, M; Fujiwara, H; Thompson, D C
2001-11-28
The metabolism, covalent binding and hepatotoxicity of butylated hydroxytoluene (BHT, 4-methyl-2,6-di-t-butylphenol) and two congeners (E-BHT, 4-ethyl-2,6-di-t-butylphenol; I-BHT, 4-isopropyl-2,6-di-t-butylphenol) were compared using precision-cut liver slices prepared from phenobarbital (PB)-treated male Sprague-Dawley rats. At equimolar concentrations (1 mM) BHT was the most toxic of the three compounds, causing an 80% decrease in cell viability over a 6 h incubation period. E-BHT was intermediate in toxicity while the isopropyl derivative was relatively nontoxic. Intracellular glutathione levels decreased prior to the onset of cytotoxicity. The cytochrome P450 inhibitor metyrapone completely inhibited the toxicity of all three compounds. The rates of metabolism of the three compounds to glutathione conjugates were compared in both PB-treated microsomes and PB-induced liver slices. In both models, the rate of formation was greatest for BHT, followed by E-BHT and I-BHT. Synthetic quinone methides (QMs) were prepared from each parent phenol and the rates of reactivity with three nucleophiles (water, methanol and glutathione) were compared. With each nucleophile, BHTQM was the most reactive, while I-BHTQM was the least reactive. Finally, covalent binding to protein was assessed in two ways. First, alkylation of an isolated model protein (bovine insulin) was measured in a microsomal enzyme activation system by mass spectrometry. Incubations with BHT produced the greatest extent of protein alkylation, followed by E-BHT, while no alkylation was observed with I-BHT. In the second system, covalent binding to cellular protein was assessed in rat liver PB microsomes and tissue slices by Western blotting using an antibody specific for the tert-butylphenol portion of the compounds. Binding was greatest for BHT, intermediate for E-BHT and could not be detected for I-BHT. The alkylation pattern for E-BHT was strikingly similar to that of BHT, suggesting that both compounds
Faine, L A; Rodrigues, H G; Galhardi, C M; Ebaid, G M X; Diniz, Y S; Fernandes, A A H; Novelli, E L B
2006-01-01
Recent lines of evidences indicate that several pathological conditions, as cardiovascular diseases, are associated with oxidative stress. In order to validate a butylated hydroxytoluene (BHT)-induced experimental model of oxidative stress in the cardiac tissue and serum lipids, 12 Wistar rats were divided into two groups, a control group and the BHT group, which received BHT i.p. twice a week (1500 mg/kg body weight) during 30 days. BHT group presented lower body weight gain and heart weight. BHT induced toxic effects on serum through increased triacylglycerols (TG), VLDL and LDL-cholesterol concentrations. The heart of BHT animals showed alteration of antioxidant defenses and increased concentrations of lipid hydroperoxides, indicating elevated lipoperoxidation. TG concentrations and lactate dehydrogenase activities were elevated in the cardiac muscle of BHT animals. Thus, long-term administration of BHT is capable to induce oxidative and metabolic alterations similarly to some pathological disorders, constituting an efficient experimental model to health scientific research.
Hyink, Otto; Balakrishnan, Mayooran; Tagg, John R
2005-11-15
Streptococcus rattus strain BHT is a species representative and strong bacteriocin producer. Here we report that S. rattus BHT produces two quite different types of bacteriocin activity, named BHT-A and BHT-B. The two bacteriocins were purified and analysed for activity and by MALDI-TOF mass spectrophotometry. BHT-A was found to be a variant of the two-component lantibiotic, Smb. BHT-B is a non-modified 5195Da peptide with some similarity to the tryptophan-rich Staphylococcus aureus bacteriocin, aureocin A53. Six S. rattus and two S. mutans strains were found to contain both the BHT-A and BHT-B genetic loci.
Scientific Opinion on the re‐evaluation of butylated hydroxytoluene BHT (E 321) as a food additive
National Research Council Canada - National Science Library
2012-01-01
...‐evaluating the safety of butylated hydroxytoluene (BHT) (E 321). BHT is an authorised synthetic antioxidant that was previously evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA...
Ibtissem, Bouftira; Imen, Mgaidi; Souad, Sfar
2010-01-01
A naturally occurring BHT was identified in the leaves of the halophyte plant Mesembryanthemum crystallinum. This phenol was extracted in this study by two methods at the different plant growth stages. One of the methods was better for BHT extraction; the concentration of this phenol is plant growth stage dependent. In this study, the floraison stage has the highest BHT concentration. The antioxidant activity of the plant extract was not related to BHT concentration. The higher antioxidant activity is obtained at seedlings stage.
Quasi-local conserved charges in Lorenz-diffeomorphism covariant theory of gravity
Energy Technology Data Exchange (ETDEWEB)
Adami, H.; Setare, M.R. [University of Kurdistan, Department of Science, Sanandaj (Iran, Islamic Republic of)
2016-04-15
In this paper, using the combined Lorenz-diffeomorphism symmetry, we find a general formula for the quasi-local conserved charge of the covariant gravity theories in a first order formalism of gravity. We simplify the general formula for the Lovelock theory of gravity. Afterwards, we apply the obtained formula on BHT gravity to obtain the energy and angular momentum of the rotating OTT black hole solution in the context of this theory. (orig.)
Dramatic solvent effect on the synergy between α-tocopherol and BHT antioxidants.
Marteau, Clémentine; Favier, Dominique; Nardello-Rataj, Véronique; Aubry, Jean-Marie
2014-10-01
During the DPPH scavenging assay carried out in non polar and non protic solvents, such as toluene, BHT regenerates α-tocopherol from tocopheryl radical, whereas in polar and protic solvents, like methanol, no regeneration is observed due to a fast electron transfer reaction from the tocopheryl radical to the reactive DPPH radical. Surprisingly, in the presence of a small amount of alcohol, the synergy is exalted and BHT regenerates twice as much α-tocopherol due to a nucleophilic addition of short alcohols on the BHT oxidation product, giving a new phenolic co-antioxidant. Copyright © 2014 Elsevier Ltd. All rights reserved.
De Bakker, B V; Bakker, Bas de; Smit, Jan
1994-01-01
We look at gravitational attraction in simplicial gravity using the dynamical triangulation method. On the dynamical triangulation configurations we measure quenched propagators of a free massive scalar field. The masses measured from these propagators show that gravitational attraction is present.
Fries, Elke; Püttmann, Wilhelm
2002-05-01
The antioxidant 3,5-di-tert-butyl-4-hydroxy-toluene (BHT) is widely used as an additive to increase the tenability of food and plastics. BHT is degraded to 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO) in mammals, as well as in the natural environment such as in water and soils. BHT-CHO has been studied extensively in terms of their potential toxicities. The present investigation was carried out to quantify BHT and BHT-CHO in river, ground, rain and drinking water obtained from several locations in Germany. Apart from the compounds mentioned above, 1,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)ethane (2-BHT), which is a dimer of BHT, was also detected in the extracts of some ground water samples. The applied analytical method is based on solid phase extraction (SPE) to concentrate trace compounds from water samples followed by gas chromatography/mass spectrometry (GC/MS) of the extracts. A total of 51 of the respective water samples were used for extraction purposes and analyte recoveries were all > or = 80%. The determination limit for BHT was 5 ng l(-1) and for BHT-CHO 16 ng l(-1). The standard deviations for the analytical procedure were 6% for BHT and 10% for BHT-CHO. The use of the antioxidant BHT in Germany has resulted in water concentrations of 7-791 ng l(-1) in the rivers Rhine, Elbe, Main, Oder, Nidda and Schwarzbach. The degradation product BHT-CHO was also detected in the river water samples at concentrations between 29 and 223 ng l(-1). The concentrations of BHT measured in German rivers are lower compared to values measured in the USA and Japan 20 years ago. In ground water, levels for BHT varied from non-detectable up to 2156 ng l(-1) and for BHT-CHO from non-detectable up to 674 ng l(-1). Both compounds were also detected in rain water in Frankfurt/Main at a concentration of 1797 ng l(-1) for BHT and 59 ng l(-1) for BHT-CHO.
Yehye, Wageeh A; Rahman, Noorsaadah Abdul; Ariffin, Azhar; Abd Hamid, Sharifah Bee; Alhadi, Abeer A; Kadir, Farkaad A; Yaeghoobi, Marzieh
2015-08-28
Hindered phenols find a wide variety of applications across many different industry sectors. Butylated hydroxytoluene (BHT) is a most commonly used antioxidant recognized as safe for use in foods containing fats, pharmaceuticals, petroleum products, rubber and oil industries. In the past two decades, there has been growing interest in finding novel antioxidants to meet the requirements of these industries. To accelerate the antioxidant discovery process, researchers have designed and synthesized a series of BHT derivatives targeting to improve its antioxidant properties to be having a wide range of antioxidant activities markedly enhanced radical scavenging ability and other physical properties. Accordingly, some structure-activity relationships and rational design strategies for antioxidants based on BHT structure have been suggested and applied in practice. We have identified 14 very sensitive parameters, which may play a major role on the antioxidant performance of BHT. In this review, we attempt to summarize the current knowledge on this topic, which is of significance in selecting and designing novel antioxidants using a well-known antioxidant BHT as a building-block molecule. Our strategy involved investigation on understanding the chemistry behind the antioxidant activities of BHT, whether through hydrogen or electron transfer mechanism to enable promising anti-oxidant candidates to be synthesized. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
Influence of BHT inclusion on post-thaw attributes of human semen.
Ghorbani, Marzieh; Amiri, Iraj; Khodadadi, Iraj; Fattahi, Amir; Atabakhsh, Mojgan; Tavilani, Heidar
2015-01-01
The aim of this study was to determine the effect of butylated hydroxytoluene (BHT) supplemented cryopreservation medium on sperm parameters during the freeze-thaw process. In addition, sperm lipid peroxidation, DNA damage, and the amount of reactive oxygen species (ROS) were determined. Semen samples were obtained from 75 donors. Fifteen semen samples were used for optimizing BHT concentration and incubation time and 60 samples were used for the final experiments. After the determination of basic parameters, groups of three sample with similar parameters were pooled and processed by Pure Sperm gradient centrifugation. The semen samples were then diluted with normal freezing medium (control) or a medium containing 0.5 mM BHT (test) for 5 minute and stored in liquid nitrogen. Frozen cryovials were thawed individually for 20 seconds in a water bath (37°C) for evaluation. Freezing extenders supplemented with 0.5 mM BHT led to higher sperm motility and viability compared with control samples (p BHT decreased malondialdehyde (MDA) formation, DNA fragmentation, and ROS content compared with controls (p BHT to the freezing medium could be of advantage in reducing ROS and preventing the detrimental effect of ROS on the human sperm function.
Öğretmen, F; İnanan, B E
2014-12-30
The aim of the present study was to test the effects of butylated hydroxytoluene (BHT) on the cryopreservation of common carp spermatozoa. BHT is widely used in the cryopreservation of the spermatozoa of different animal species and successfully sustains the characteristics of spermatozoa during freezing and thawing, but it has not previously been used with fish. After sampling, common carp spermatozoa were diluted with an extender composed of modified Kurokura's extender, 10% DMSO, and 10% egg yolk containing 0.0001, 0.001, 0.01, 0.1, 1, 2.5, 5, or 10mM BHT and subsequently frozen in liquid nitrogen. The post-thaw spermatozoa characteristics (i.e., progressive motility percentage (%), duration of progressive motility (s), fertilization rate (%), and eyed-eggs rate (%)) were evaluated and compared with those of the control group. There were significant increases in the percentage of progressive motility and the duration of progressive motility at the concentrations of 0.1 and 0.001mM BHT (PBHT was significantly greater than that of the other groups (39.6±0.4s, PBHT treatments. BHT at concentrations of more than 1mM caused sperm immobility during the preparatory stages of the sperm freezing. We concluded that 0.001-0.1mM BHT can be beneficial for the cryopreservation of common spermatozoa. Copyright © 2014 Elsevier B.V. All rights reserved.
Castro, Lorena Dos Santos; Bracht, Lívia; Comar, Jurandir Fernando; Peralta, Rosane Marina; Bracht, Adelar
2017-08-01
Butylated hydroxytoluene (BHT) was investigated for its metabolic actions in the perfused rat liver. Contrary to what is expected from an uncoupler, BHT up to 500 μM did not stimulate oxygen uptake nor did it inhibit gluconeogenesis from lactate. Transformation of fructose into glucose was also not affected by BHT; only lactate production was slightly increased at the concentration of 100 μM. The uncoupling effect of BHT in isolated mitochondria was confirmed, but only at concentrations above 10 μM; uncoupling at lower concentrations, 10(-9) to 10(-6) M, could not be confirmed. BHT, however, increased reactive oxygen species (ROS) production in isolated mitochondria, starting at the concentration of 10(-8) M. This is the opposite of what can be expected from a compound with proven ex vivo antioxidant action. One cannot exclude the possibility that, in mitochondria, stimulation of ROS production rather than uncoupling could be the most significant effect of BHT. © 2017 Wiley Periodicals, Inc.
No consistent bimetric gravity?
Deser, S; Waldron, A
2013-01-01
We discuss the prospects for a consistent, nonlinear, partially massless (PM), gauge symmetry of bimetric gravity (BMG). Just as for single metric massive gravity, ultimate consistency of both BMG and the putative PM BMG theory relies crucially on this gauge symmetry. We argue, however, that it does not exist.
Reed, M; Thompson, D C
1997-10-01
Several alkylphenols (e.g., 2,6-di-tert-butyl-4-methylphenol, BHT) form reactive quinone methide intermediates (e.g., 2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone, BHT-QM) upon oxidation by cellular enzymes. In order to pursue the role of protein alkylation in alkylphenol toxicity, we used an immunochemical approach to identify protein targets alkylated by BHT. Synthetic BHT-N-acetylcysteine (BHT-NAC) was coupled to keyhole limpet hemocyanin and used as an antigen from which polyclonal antibodies were raised in New Zealand white rabbits. Rabbit serum contained an antibody which was highly specific for BHT-NAC, as determined by competitive ELISA. The BHT antibody was used as a probe to look for the presence of BHT-protein adducts in in vitro incubations with rat liver microsomes or tissue slices and also in vivo in liver tissue from male Sprague-Dawley rats exposed to BHT. Western blotting of protein gels revealed BHT-dependent protein alkylation over a wide molecular weight range. Prominent recurrent bands were observed at approximately 34.5, 52, 64.5, 74, and 97 kDa. Detection of adducts was inhibited in microsomal incubations by cytochrome P450 inhibitors, deuterated BHT, and the omission of NADPH. Similar protein alkylation patterns were observed in rat liver microsomes exposed to synthetically prepared BHT-QM as in the enzyme-mediated incubations. In rats gavaged with up to 1000 mg/kg BHT, the amount of protein alkylation observed was maximal at 24 h postdosing and was dose-dependent. Two alkylated proteins were isolated and identified by N-terminal sequencing: a mitochondrial beta-oxidation enzyme, enoyl-CoA hydratase, and a plasma membrane/cytoskeletal linker protein from the ezrin/moesin/radixin family.
Gauge Model with Massive Gravitons
Institute of Scientific and Technical Information of China (English)
WU Ning
2003-01-01
Gauge theory of gravity is formulated based on principle of local gauge invariance. Because the model hasstrict local gravitational gauge symmetry, and gauge theory of gravity is a perturbatively renormalizable quantum model.However, in the original model, all gauge gravitons are massless. We want to ask whether there exist massive gravitonsin Nature. In this paper, we will propose a gauge model with massive gravitons. The mass term of gravitational gaugefield is introduced into the theory without violating the strict local gravitational gauge symmetry. Massive gravitons canbe considered to be possible origin of dark energy and dark matter in the Universe.
Butylhydroxytoluene (BHT) increases susceptibility of transgenic rasH2 mice to lung carcinogenesis.
Umemura, T; Kodama, Y; Hioki, K; Inoue, T; Nomura, T; Kurokawa, Y
2001-10-01
Transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) are highly susceptible to lung carcinogens. In order to investigate the possibility of developing a rapid in vivo assay for lung carcinogens, we examined whether the tumor-promoting activity of butylhydroxytoluene (BHT) is efficacious in rasH2 mice. rasH2 mice and wild littermates of both genders were pre-treated with carcinogens [urethane (UR), 4-nitroquinoline 1-oxide (4NQO) or diethylnitrosamine (DEN)], and, one day later, given a 400 mg/kg dose of BHT. Six weeks after the initiation treatment, evidence of carcinogenicity could be detected in male and female rasH2 mice that had received UR doses of > or = 250 mg/kg and > or = 125 mg/kg, respectively, prior to exposure to BHT, whereas only 500 mg/kg of UR was sufficient to induce tumors in female rasH2 mice given the carcinogen alone. The carcinogenicity of 15 mg/kg of 4NQO could be detected after 9 weeks in male rasH2 mice given the carcinogen followed by BHT. Similarly, the carcinogenicity of 60 mg/kg of DEN could be detected after 9 weeks and 6 weeks, respectively, in male and female rasH2 mice given the carcinogen followed by BHT. No carcinogenicity could be demonstrated through the experimental period with doses of 4NQO or DEN given alone. These results indicate that BHT administration increases the susceptibility of rasH2 mice to lung carcinogens, and suggest that the use of BHT in rasH2 mice might lead to the establishment of a rapid in vivo assay for lung carcinogens.
Positivity constraints for pseudolinear massive spin-2 and vector Galileons
Bonifacio, James; Hinterbichler, Kurt; Rosen, Rachel A.
2016-11-01
We derive analyticity constraints on a nonlinear ghost-free effective theory of a massive spin-2 particle known as pseudolinear massive gravity, and on a generalized theory of a massive spin-1 particle, both of which provide simple IR completions of Galileon theories. For pseudolinear massive gravity we find that, unlike de Rham, Gabadadze, and Tolley massive gravity, there is no window of parameter space which satisfies the analyticity constraints. For massive vectors which reduce to Galileons in the decoupling limit, we find that no two-derivative actions are compatible with positivity but that higher derivative actions can be made compatible.
Carcinogenicity study on butylated hydroxytoluene (BHT) in Wistar rats exposed in utero
DEFF Research Database (Denmark)
Olsen, P.; Meyer, Otto A.; Bille, N.
1986-01-01
Groups of 60, 40, 40 and 60 F0 Wistar rats of each sex were fed a semi-synthetic diet containing butylated hydroxytoluene (BHT) in concentrations to provide intakes of 0, 25, 100 or 500 mg/kg body weight/day, respectively. The F0 rats were mated and groups of 100, 80, 80 or 100 F1 rats of each sex...... were formed from 40, 29, 30 and 44 litters, respectively. After weaning, the highest dose (500 mg BHT/kg/day) was lowered to 250 mg/kg/day for the F1 rats. The numbers of litters of ten or more pups at birth decreased with increasing BHT dose. At weaning, treated F1 rats had lower body weights than...... the controls, the extent of the reduction being dose related; the effect, which persisted throughout the study, was most pronounced in the males. The survival of BHT-treated F1 rats of both sexes was significantly better than that of the controls. No significant changes attributable to BHT treatment were found...
Sai-Ut, Samart; Benjakul, Soottawat; Rawdkuen, Saroat
2015-09-01
The aim of the present work was to apply the gelatin films with different levels of longan seed extract (LS) or butylated hydroxytoluene (BHT) on retardation of lipid oxidation in soybean oil. The films incorporated with various concentrations of aqueous LS (0, 50, 100, 300, and 500 ppm) or BHT (50, and 100 ppm) were developed. The films had transmittance percentages of 60-80 % at 570 nm and showed good light barrier properties when the concentration of LS or BHT increased. About 97 % protein solubility and 41 to 54 % water solubility were obtained for the developed films. Antioxidative activity of gelatin films incorporated with LS increased markedly with increasing storage time as indicated by the increase in DPPH radical scavenging activity (41-50 %) (P BHT showed the preventive effect on lipid oxidation of soybean oil during 30 days of storage. At the level of 500 ppm, LS provided the highest efficacy for lipid oxidation retardation as evidenced by lower conjugated diene (CD) values (P > 0.05). According to these findings, gelatin film incorporated with longan seed extract or BHT could be used as a tool to prolong the shelf-life of oily foods.
Chern-Simons-like Gravity Theories
Bergshoeff, Eric A.; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.
2014-01-01
A wide class of three-dimensional gravity models can be put into "Chern-Simons-like" form. We perform a Hamiltonian analysis of the general model and then specialise to Einstein-Cartan Gravity, General Massive Gravity, the recently proposed Zwei-Dreibein Gravity and a further parity violating
Butylated hydroxytoluene (BHT) induction of pulmonary inflammation: a role in tumor promotion.
Bauer, A K; Dwyer-Nield, L D; Keil, K; Koski, K; Malkinson, A M
2001-01-01
Chronic pulmonary inflammatory diseases predispose towards lung cancer by unknown mechanisms. Butylated hydroxytoluene (BHT) administration to mice causes lung injury and a subsequent inflammatory response, and when administered chronically to certain inbred strains following carcinogen treatment, increases lung tumor multiplicity. We hypothesize that inflammation promotes lung tumor growth in this model system and have begun to examine this hypothesis by assessing inflammatory parameters in inbred strains that vary in their susceptibility to promotion. Positive correlations were found between susceptibilities to tumor promotion and BHT induction of alveolar macrophage and lymphocyte infiltration into alveolar airspaces, and increased vascular permeability (P BHT, along with decreased tumorigenesis after macrophage depletion, are consistent with a role of inflammation in promotion. Inflammatory mediators may provide targets for early diagnosis and chemoprevention.
Maziero, G C; Baunwart, C; Toledo, M C
2001-05-01
The theoretical maximum daily intakes (TMDI) of the phenolic antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tertbutyl hydroquinone (TBHQ) in Brazil were estimated using food consumption data derived from a household economic survey and a packaged goods market survey. The estimates were based on maximum levels of use of the food additives specified in national food standards. The calculated intakes of the three additives for the mean consumer were below the ADIs. Estimates of TMDI for BHA, BHT and TBHQ ranged from 0.09 to 0.15, 0.05 to 0.10 and 0.07 to 0.12 mg/kg of body weight, respectively. To check if the additives are actually used at their maximum authorized levels, analytical determinations of these compounds in selected food categories were carried out using HPLC with UV detection. BHT and TBHQ concentrations in foodstuffs considered to be representive sources of these antioxidants in the diet were below the respective maximum permitted levels. BHA was not detected in any of the analysed samples. Based on the maximal approach and on the analytical data, it is unlikely that the current ADI of BHA (0.5 mg/kg body weight), BHT (0.3 mg/kg body weight) and TBHQ (0.7 mg/kg body weight) will be exceeded in practice by the average Brazilian consumer.
The mouse rasH2/BHT model as an in vivo rapid assay for lung carcinogens.
Umemura, Takashi; Kodama, Yukio; Hioki, Kyoji; Nomura, Tatsuji; Nishikawa, Akiyoshi; Hirose, Masao; Kurokawa, Yuji
2002-08-01
We have demonstrated the utility of a 9-week in vivo two-stage assay for lung cancer initiating agents, using transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) and butylhydroxytoluene (BHT) as a potent lung promoter (rasH2/BHT model). In the present study, to ascertain appropriate conditions for BHT administration in this model, the effects of exposure on proliferation of alveolar type II cells in male rasH2 mice were examined. Additionally, use of BHT was validated for promotion of urethane (UR) carcinogenesis in male and female rasH2 mice. In a time-course study of a single intragastric administration of BHT at a dose of 400 mg/kg, increased bromodeoxyuridine-labeling index (LI) reached a maximum 3 days after treatment and was still observed after 7 days. In a dose-response study, effects were dose-dependent, the dose of 400 mg/kg causing eight-fold elevation as compared to the control. With repeated administration, whereas the LI was increased dramatically at first, effects gradually diminished with further exposure, and finally six BHT treatments failed to induce cell proliferation. In a two-stage model using UR as the initiator, although up to five consecutive doses of BHT were able to exert continued enhancing effects in terms of adenoma yield, no increment was evident with further treatments. The data overall indicate that a rasH2/BHT model with five weekly administrations of BHT at a dose of 400 mg/kg is most efficacious.
Cosmological solutions with massive gravitons
Energy Technology Data Exchange (ETDEWEB)
Chamseddine, Ali H. [Physics Department, American University of Beirut (Lebanon); Laboratoire de Mathematiques et Physique Theorique CNRS-UMR 6083, Universite de Tours, Parc de Grandmont, 37200 Tours (France); LE STUDIUM, Loire Valley Institute for Advanced Studies, Tours and Orleans (France); I.H.E.S., F-91440 Bures-sur-Yvette (France); Volkov, Mikhail S., E-mail: volkov@lmpt.univ-tours.fr [Laboratoire de Mathematiques et Physique Theorique CNRS-UMR 6083, Universite de Tours, Parc de Grandmont, 37200 Tours (France)
2011-10-25
We present solutions describing spatially closed, open, or flat cosmologies in the massive gravity theory within the recently proposed tetrad formulation. We find that the effect of the graviton mass is equivalent to introducing to the Einstein equations a matter source that can consist of several different matter types - a cosmological term, quintessence, gas of cosmic strings, and non-relativistic cold matter.
National Research Council Canada - National Science Library
Biparva, P; Hadjmohammadi, M.R; Ehsani, M; Kamel, K
2012-01-01
The optimal conditions of liquid–liquid extraction of two synthetic phenolic antioxidants, BHA and BHT were investigated in five Iranian edible vegetable oil samples using the central composite design...
Livio, Mario; Villaver, Eva
2009-11-01
Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.
Directory of Open Access Journals (Sweden)
Chi Haitao
2015-09-01
Full Text Available Made of High Density Polyethylene (HDPE films containing antioxidant 2, 6-di-tert-butyl-p-cresol (BHT, film samples were manufactured by plastic extrusion equipment, 95% ethanol aqueous solution simulating liquid was used for stimulant, using High Performance Liquid Chromatography (HPLC for the long-term migration test of 4 kinds of HDPE films containing different concentrations of antioxidant BHT. The migration data were processed by using Weibull model and then the migration model was specific under experimental conditions. Migration model was setup using the migrating data by Weibull model to fitting real experimental data. Using empirical formula reported FDA model formula and the diffusion coefficient constant D, calculated by the FDA model. Two kinds of model numerical after compared according to FDA model transfer numerical literature that is far lower than the actual test migration value. According to the actual test migration value, Weibull model numerical and experimental tests that the migration software fitting values are consistent.
Intranasal application of the alpha2-adrenoceptor agonist BHT-920 produces decongestion in the cat.
Mcleod, R L; Erickson, C H; Mingo, G G; Hey, J A
2001-01-01
The effect of alpha2-selective adrenoreceptor activation on nasal cavity dimension in an experimental model of congestion has not been defined. Presently, we used acoustic rhinometry to evaluate the decongestant activity of BHT-920, a selective alpha2-adrenergic agonist against nasal congestion produced by intranasal compound 48/80. Administration of the mast cell liberator compound 48/80 (1%) into a nasal passageway decreased ipsilateral volume and minimum cross-sectional area by 73 +/- 4% and 42 +/- 6%, respectively. The congestant effect of compound 48/80 was blocked by topical BHT-920 (0.3 and 1%) in a dose related manner. In addition, the decrease in minimum cross-sectional area produced by compound 48/80 was attenuated after topical BHT-920 treatment. As a comparison we also evaluated the topical decongestant activity effects of the alpha1-adrenergic agonist phenylephrine, and the nonselective alpha-agonist oxymetazoline. Both phenylephrine (0.1-1.0%) and oxymetazoline (0.01-0.3%) produced decongestion. The blood pressure effects of these three drugs also were evaluated. At doses of 0.3 and 1.0%, BHT-920 did not produce hypertension. In contrast, oxymetaZoline (0.01-0.1%) produced a transient hypertension that peaked at 15 minutes and fully recovered 45 minutes after administration. The hypertensive effect of phenylephrine at 0.3 and 1.0% lasted over 60 minutes. The present findings indicate that selective alpha2-agonists may produce decongestant activity with an improved cardiovascular profile compared with current sympathomimetic drugs such as phenylephrine.
BHT-3009, a myelin basic protein-encoding plasmid for the treatment of multiple sclerosis.
Correale, Jorge; Fiol, Marcela
2009-08-01
Even though the etiology of multiple sclerosis (MS) remains largely unknown, research data support the hypothesis that autoimmunity plays a major role in disease development. Several disease-modifying agents have been approved for the treatment of MS; however, there is still a need for antigen-specific treatments that combine efficacy and safety. DNA vaccination represents a new therapeutic alternative in this respect. Preclinical studies in different models of autoimmunity have demonstrated that injection of plasmid DNA encoding a self-antigen in mice restores self-tolerance, leaving immunity against infectious and tumor antigens intact. Based on this evidence, the first DNA vaccine for MS has been created. Bayhill Therapeutic Inc's BHT-3009 encodes full-length, human myelin basic protein (MBP), and has recently been evaluated in a phase I/II and a phase II clinical trial. BHT-3009 was safe and well tolerated in both trials, inducing immune tolerance that extended beyond MBP to other myelin antigens. In addition, a reduction in the number of active lesions was observed, which was accompanied by a decrease in clinical relapse rates, particularly in patients with high immunological activity at baseline. BHT-3009 appears to be a promising new approach for the treatment of MS, although further clinical trials are warranted to confirm the early findings.
Krasowska, A; Rosiak, D; Szkapiak, K; Oświecimska, M; Witek, S; Lukaszewicz, M
2001-01-01
The antioxidative properties of two series of new phenolic, amphiphilic compounds were evaluated using the chemiluminescence (CL) method. 2,2'-Azobis (2-amidinopropane) dihydrochloride (AAPH) was used as a source of free radicals, to obtain high and prolonged CL. Three different kinds of buffers (organic and inorganic) were tested. The CL level varied only slightly depending on the buffer but increased significantly with the pH. Twelve newly synthesised compounds were compared with butylated hydroxytoluene (BHT), a commercially used antioxidant. The new antioxidants included two classes of quaternary ammonium salts with a phenol substituent functioning as an antioxidant. The salts were synthesised by quaternarization of pyrrolidine ethyl esters of dihydrocinnamic acid by n-alkoxymethyl bromides (PYA-n) or quaternarization of 2-dimethylaminoethyl esters by n-alkyl bromides (PPA-n). All the tested compounds quenched CL proportionally to their concentrations. In our experimental conditions 8.5 microM BHT quenched 50% of the CL. The PYA and PPA compounds had IC50 two to six times lower than BHT. CL inhibition was proportional to the pH for all antioxidants. The relationships between the structure and activity of the tested compounds are discussed.
Devi, R S; Narayan, Shoba; Mohan, K Vijai; Sabitha, K E; Devi, C S Shyamala
2003-11-01
Effect of polyherbal formulation Ambrex was evaluated in butylated hydroxytoluene (BHT) induced toxicity of lungs and liver in rats. Toxicity was produced by administering BHT (500 mg/kg/day) for 3 days. Lung damage was evidenced by elevated levels of broncho alveolar lavage fluid (BAL) parameters such as protein, lactate, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), acid phosphatase (ACP) and glucose-6-phosphate dehydrogenase (G6PDH). Liver damage was proved by elevated levels of serum protein and markers such as LDH, ALP, aspartate amino transferase (AST), alanine amino transferase (ALT), decreased level of lipid peroxides (LPO) in serum and glutathione (GSH) in liver. Administration of aqueous suspension of Ambrex (50 mg/kg orally) retained these elevated levels of BAL-protein, lactate, LDH, ALP, ACP, G6PDH and serum-protein, LDH, ALP, AST and ALT at near normal values. Decreased level of liver GSH was retained at near normalcy in Ambrex pretreated BHT-administered animals. There was no change in liver LPO in all the four groups.
Effects of water extracts from chicory and BHT on the in vitro rumen degradation of feeds
Directory of Open Access Journals (Sweden)
Stefano Schiavon
2010-01-01
Full Text Available Effects of Butyl-Hydroxyl-Toluene (BHT and of Red Chicory Extract (RCE on kinetics of gas production (GP and rumen degradability values (OMd, NDFd and in vitro true OM degradability - IVTOMD of two feeds (meadow hay and corn meal were evaluated using an in vitro automatic batch system. For each feed 2 increasing dosages (0.15 and 1.5 mg/g of feed of BHT and RCE and a Control (C were tested in 4 replications and 2 incubations. First incubation lasted 72h, the 2nd one was stopped at the times on which half of GP was produced (t½, which were 9 and 16 h for corn and hay, respectively. From the supernatants of the 2nd incubation, VFA, NH3, N content of the residual NDF were analysed and the microbial N balance was computed. The 2 feeds significantly affected rumen fermentation parameters; BHT significantly increased asymptotic GP, t½ and IVTOMD (P<0.01, decreased the proportion of butyrate (P<0.01 but did not affect microbial N balance; RCE did not influence any of the parameters measured with respect to C, except for a significant increase of the estimated N available for microbes at the higher dosage.
Doubly coupled matter fields in massive bigravity
Gao, Xian
2016-01-01
In the context of massive (bi-)gravity non-minimal matter couplings have been proposed. These couplings are special in the sense that they are free of the Boulware-Deser ghost below the strong coupling scale and can be used consistently as an effective field theory. Furthermore, they enrich the phenomenology of massive gravity. We consider these couplings in the framework of bimetric gravity and study the cosmological implications for background and linear tensor, vector, and scalar perturbations. Previous works have investigated special branch of solutions. Here we perform a complete perturbation analysis for the general background equations of motion completing previous analysis.
Freyschuss, A; Al-Schurbaji, A; Björkhem, I; Babiker, A; Diczfalusy, U; Berglund, L; Henriksson, P
2001-12-30
We have shown that inclusion of the antioxidant butylated hydroxytoluene (BHT) in the diet protects against development of atherosclerotic lesions in cholesterol-fed rabbits. In parallel, BHT treatment results in increased plasma triglyceride levels. The present study explores the relationship between the triglyceride-inducing and protective effects of BHT in two different studies. The combined material contains 22 rabbits fed cholesterol and 18 rabbits fed cholesterol in combination with 1% BHT. In the BHT group there was an inverse relationship between triglyceride exposure/cholesterol exposure and extent of lesions with r=0.74 (P=0.0005). Our results show that increased triglyceride exposure parallels the anti-atherogenic effect of BHT. There was no significant correlation between atheromatosis and serum BHT levels. beta-very low density lipoprotein (beta-VLDL) from cholesterol and BHT animals was triglyceride-enriched and smaller compared to beta-VLDL from cholesterol-fed animals, but there was no significant association between the anti-atherogenic effect of BHT and particle size or apolipoprotein pattern of LDL or beta-VLDL. LDL isolated from rabbits treated with cholesterol and BHT was less sensitive to oxidative modification than LDL isolated from rabbits treated with cholesterol only. In conclusion, our results demonstrate that the degree of triglyceride exposure may be an important modulator of the anti-atherogenic effect of an antioxidant.
Masters, Roy
2010-03-01
Flowing global gravitation initially produced space without time or mass. Space-time and mass are properties of flowing global gravitation. From its fabric, primal mass spins spontaneously giving rise to local gravitational space-time curvatures. Global gravity is the unifying background field. Gravity began flowing from its singularity with a big whoosh. It curves with angular rotational precession, creating a spatial geometry similar to the windings of a ball of string. Three-dimensional global gravity swirls locally into massive densities. Concurrently with these densities, local gravity curvatures of space-time arise. The expanse between celestial objects is not completely empty, void space as generally believed; it is antecedent gravity, a prerequisite associated field necessary for originating the first quantum particles. Gravity is dark energy; gravity's spin, as the second fundamental force, is electromagnetic dark matter. Electromagnetic masses attract then gravity compresses hot, dense and small---then bang, the first hydrogen star of which there are many. There may have been many big bangs, but no Big Bang that ultimately created the universe.
Suh, H-J; Chung, M-S; Cho, Y-H; Kim, J-W; Kim, D-H; Han, K-W; Kim, C-J
2005-12-01
The study was conducted to establish the estimated daily intake (EDI) of antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) in Korea. The EDIs were obtained from two sources. One of the estimations was based on the analytical determination of BHA, BHT and TBHQ in 12 food categories (ten food categories for TBHQ) and on individual dietary intake data obtained from the National Health and Nutrition Survey in 1998 (n=11 525, age > 1 year). The other EDIs of BHA, BHT and TBHQ were based on the maximum permitted levels specified in national food standards in Korea and on individual dietary intake data obtained from the National Health and Nutrition Survey in 1998 (n=11 525, age > 1 year). To establish the EDIs based on the analytical determination and on individual dietary intake data, 133 food samples in 12 food categories were selected from the foods considered to be representative sources of BHA, BHT and TBHQ in the Korean diet. Selected samples were analysed by GC with FID. BHA was not detected in any of the samples analysed. BHT and TBHQ were detected in the samples, but the levels were significantly lower than their maximum limits. The EDIs1 of BHT, and TBHQ for average consumers were 0.0156(-3), and 0.0012(-3) mg kg(-1) body weight bw day(-1) and as a proportion of the ADI were 0.0052 and 0.0002%, respectively. For 95th percentile consumers, the EDIs of BHT and TBHQ were 0.0080 and 0.0006 mg kg(-1) bw day(-1), and as a proportion of the ADI were 2.67 and 0.09%, respectively. EDIs for BHA, BHT and TBHQ based on the maximum permitted levels and on individual dietary intake data were 0.04, 0.04 and 0.04 mg kg(-1) bw day(-1), respectively. The EDIs of BHA, BHT and TBHQ for average consumers ranged from 6.00 to 14.42% of the ADI of each antioxidant. According to these results, the EDIs of BHA, BHT and TBHQ in Korea were significantly lower than ADI of these antioxidants established by the JECFA.
Infrared Modifications Of Gravity
Rombouts, J
2005-01-01
In this thesis, we study theories that modify gravity at very large distances. Motivated by recent observations in cosmology, such as the dimming of type Ia supernovae and flattening of rotation curves of galaxies, we study two classes of theories that attempt to explain these observations as due to a change in the laws of gravity at large distances rather than due to the presence of new forms of exotic energy and matter. The first class of theories is massive gravity, obtained by adding a mass term to the action for the gravitational fluctuation in Einstein's general relativity. The second class of models we study are braneworlds that provide infrared modified gravity, in specific the Dvali-Gabadadze-Porrati model and its extension to higher codimensional branes. We stress in our discussion the field theoretical consistency, both classically and quantum-mechanically, of these models.
Positivity Constraints for Pseudo-linear Massive Spin-2 and Vector Galileons
Bonifacio, James; Rosen, Rachel A
2016-01-01
We derive analyticity constraints on a nonlinear ghost-free effective theory of a massive spin-2 particle known as pseudo-linear massive gravity, and on a generalized theory of a massive spin-1 particle, both of which provide simple IR completions of Galileon theories. For pseudo-linear massive gravity we find that, unlike dRGT massive gravity, there is no window of parameter space which satisfies the analyticity constraints. For massive vectors which reduce to Galileons in the decoupling limit, we find that no two-derivative actions are compatible with positivity, but that higher derivative actions can be made compatible.
Frank, Jan; Lundh, Torbjörn; Parker, Robert S; Swanson, Joy E; Vessby, Bengt; Kamal-Eldin, Afaf
2003-10-01
The effects of dietary (+)-catechin (CAT) and BHT on plasma and tissue concentrations of alpha-tocopherol (alpha-T), gamma-tocopherol (gamma-T) and cholesterol (C) were studied in male Sprague-Dawley rats. The rats were fed the compounds during a 4-wk period at concentrations of 2 g/kg in standardized diets, low but adequate in vitamin E, with 2 g/kg cholesterol. The CAT-regimen did not affect weight gain, feed intake or organ weights. BHT did not affect feed intake but lowered the body weight and the amount of liver lipids and increased the weights of livers and lungs relative to the body weight. Rats consuming CAT had 2.5-3.5-fold increased plasma, liver and lung alpha-T concentrations, but C concentrations remained unchanged. BHT-feeding resulted in 2.4- and 1.7-fold elevation in alpha-T but approximately 50% decrease in gamma-T concentrations in blood plasma and liver, respectively. BHT also lowered total C in the liver without affecting the concentration of C in the liver lipids. To investigate whether the alpha-T-sparing action of the studied compounds was due to the inhibition of tocopherol-omega-hydroxylase, HepG2 cells were incubated with CAT or BHT in the presence of delta-tocopherol (delta-T) and the 3'- and 5'-delta-carboxychromanol metabolites in the media were analyzed by GC/MS. Neither CAT nor BHT inhibited tocopherol-omega-hydroxylase activity in hepatocyte cultures; CAT was also inactive in a rat microsomal assay. In conclusion, both dietary CAT and BHT markedly increased alpha-T concentrations in plasma and organs of Sprague-Dawley rats by a mechanism that apparently does not involve inhibition of tocopherol-omega-hydroxylase, a key enzyme in tocopherol catabolism.
Zhang, Wei-Ya; Wu, Cai-Ying; Wang, Cheng-Yun; Yang, Zuo-Jun; Liu, Li
2002-03-01
A new method for the determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in cosmetics by gas chromatography-mass spectrometry selected ion storage (SIS) method was developed. The BHA and BHT in samples were extracted by methanol. The m/z 165 and m/z 205 were the monitoring ion for BHA and BHT respectively. The detection limits of BHA and BHT in samples were 2.5 micrograms/g and 0.5 microgram/g, respectively. The method is simple, rapid and accurate.
Increased Understanding of Accretion in Massive YSOs
De Wit, Willem-Jan; Caratti, A.; Kraus, S.
2017-06-01
That massive stars up to 20Msol form by disk accretion is by now reasonably well established. We will present the latest observational results for the formation of single and multiple massive YSOs. By means of optical interferometry using the newly commissioned instrument Gravity at the VLT-I, we show the discovery of a young, embedded, 170AU-wide binary and is the most massive and most compact accreting young binary to date. We will also present the results of a multi-site multi-epoch follow-up campaign of the first well studied accretion outburst in a massive YSO.
BHT blocks NF-kappaB activation and ethanol-induced brain damage.
Crews, Fulton; Nixon, Kimberly; Kim, Daniel; Joseph, James; Shukitt-Hale, Barbara; Qin, Liya; Zou, Jian
2006-11-01
Binge ethanol administration causes corticolimbic brain damage that models alcoholic neurodegeneration. The mechanism of binge ethanol-induced degeneration is unknown, but is not simple glutamate-N-methyl-D-aspartate (NMDA) excitotoxicity. To test the hypothesis that oxidative stress and inflammation are mechanisms of binge ethanol-induced brain damage, we administered 4 antioxidants, e.g., butylated hydroxytoluene (BHT), ebselen (Eb), vitamin E (VE), and blueberry (BB) extract, during binge ethanol treatment and assessed various measures of neurodegeneration. Adult Sprague-Dawley rats were treated with intragastric ethanol 3 times per day (8-12 g/kg/d) alone or in combination with antioxidants or isocaloric diet for 4 days. Animals were killed, and brains were perfused and extracted for histochemical silver stain determination of brain damage, markers of neurogenesis, or other immunohistochemistry. Some animals were used for determination of nuclear factor kappa B (NF-kappaB)-DNA binding by electrophoretic mobility shift assay (EMSA) or for reverse transcription-polymerase chain reaction (RT-PCR) of cyclooxygenase 2 (COX2). Binge ethanol induced corticolimbic brain damage and reduced neurogenesis. Treatment with BHT reversed binge induced brain damage and blocked ethanol inhibition of neurogenesis in all regions studied. Interestingly, the other antioxidants studied, e.g., Eb, VE, and BB, did not protect against binge-induced brain damage. Binge ethanol treatment also caused microglia activation, increased NF-kappaB-DNA binding and COX2 expression. Butylated hydroxytoluene reduced binge-induced NF-kappaB-DNA binding and COX2 expression. Binge-induced brain damage and activation of NF-kappaB-DNA binding are blocked by BHT. These studies support a neuroinflammatory mechanism of binge ethanol-induced brain damage.
Massive Gravitons on Bohmian Congruences
Fathi, Mohsen
2016-01-01
Taking a quantum corrected form of Raychaudhuri equation in a geometric background described by a Lorentz-violating massive theory of gravity, we go through investigating a time-like congruence of massive gravitons affected by a Bohmian quantum potential. We find some definite conditions upon which these gravitons are confined to diverging Bohmian trajectories. The respective behaviour of those quantum potentials are also derived and discussed. Additionally, and through a relativistic quantum treatment of a typical wave function, we demonstrate schematic conditions on the associated frequency to the gravitons, in order to satisfy the necessity of divergence.
Effectiveness of the antioxidants BHA and BHT in selected vegetable oils during intermittent heating
Directory of Open Access Journals (Sweden)
Protopapa, Evangelia
2002-06-01
Full Text Available The heating performance of olive oil was compared with that of corn oil, olive-residue oil and 50:50 mixture of olive oil and corn oil. The oils were heated intermittently for two hours per day at a temperature of 175 Â± 5Â° C for five consecutive days. Under such conditions thermal and oxidative decomposition of the oils takes place. Free fatty acid content, peroxide values, E1%1 cm, at 232 and 270nm, polar compounds, colour and viscosity, of the oils all increased, whereas the iodine values, smoke points, polyunsaturated fatty acids content and tocopherol concentration decreased. The effectiveness of butylated hydroxyanisole (BHA and butylated hydroxytoluene (BHT at a rate of 200 ppm in retarding the deterioration of oils during static heating (175 Â± 5Â° C, was studied and it was found that BHA gave a slight protection to the olive-residue oil and the BHT gave some protection to the corn oil, while both antioxidants were relatively ineffective in the other oils.Se ha comparado el comportamiento del aceite de oliva al calentamiento con respecto al del aceite de maíz, el aceite de orujo y una mezcla al 50 % de aceite de oliva y aceite de maíz. Los aceites fueron calentados intermitentemente durante dos horas al día a una temperatura de 175Âº C Â± 5Âº C durante cinco días consecutivos. Bajo tales condiciones tuvo lugar la descomposición térmica y oxidativa de los mismos. En todos los aceites aumentaron el contenido en ácidos grasos libres, el índice de peróxido, E1%1 cm, a 232 y 270 nm, los compuestos polares, el color y la viscosidad, mientras que el índice de yodo, el punto de humo, el contenido en ácidos grasos poliinsaturados y el contenido en tocoferoles disminuyeron. Se estudió la eficacia del 3-terc-butil-4-hidroxianisol (BHA y del butilhidroxitolueno (BHT en una proporción de 200 ppm en el retraso de la deterioración de los aceites durante el calentamiento estático (175 Â± 5Âº C, encontrándose que el BHA
Dando, O
1999-01-01
We examine the field equations of a self-gravitating texture in low-energy superstring gravity, allowing for an arbitrary coupling of the texture field to the dilaton. Both massive and massless dilatons are considered. For the massless dilaton, we find that non-singular spacetimes only exist for certain values of the coupling, dependent on the gravitational strength of the texture. For the massive dilaton, the texture induces a long-range dilaton cloud, but we expect the gravitational behaviour of the defect to be similar to that found in Einstein theory. We compare these results with those found for other global topological defects.
Sebranek, J G; Sewalt, V J H; Robbins, K L; Houser, T A
2005-02-01
A commercial rosemary extract was evaluated for antioxidant effectiveness at concentrations of 1500 and 2500 ppm in frozen and precooked-frozen pork sausage, and from 500 to 3000 ppm in refrigerated, fresh pork sausage. Thiobarbituric acid-reactive substances (TBARS), objective color values and sensory panel scores, were assessed. For refrigerated sausage, the rosemary extract at 2500 ppm was equally effective as butylated hydroxy anisole (BHA)/butylated hydroxy toluene (BHT). Similarly, the rosemary extract was equally effective as BHA/BHT in maintaining low TBARS values of precooked-frozen sausage. However, the rosemary extract was more effective than BHA/BHT for preventing increased TBARS values or loss of red color in raw frozen sausage.
Courtois, Frédéric; Delvin, Edgard; Ledoux, Marielle; Seidman, Ernest; Lavoie, Jean-Claude; Levy, Emile
2002-06-01
We showed recently that iron + ascorbate can impair the assembly of intestinal lipoproteins. However, we could not determine whether these changes were caused by iron + ascorbate-mediated lipid peroxidation per se. We therefore conducted studies to evaluate how antioxidants antagonize the iron + ascorbate-induced derangements. To this end, Caco-2 cells, a reliable experimental intestinal model, were incubated with iron + ascorbate (0.2 mmol/L each) alone or with different concentrations of catalase, mannitol, tocopherol or BHT. Exposing Caco-2 cells to iron + ascorbate increased malondialdehyde levels fourfold (P BHT. Furthermore, BHT normalized the abnormal intracellular events involved in fat absorption, i.e., lipid esterification, cholesterol synthesis and apolipoprotein production. On the other hand, it did not fully restore the secretion of lipids and lipoproteins. Thus, our current data imply that iron + ascorbate-catalyzed lipid peroxidation is partially responsible for the disturbances observed in intestinal lipid transport.
Naveena, B M; Sen, A R; Vaithiyanathan, S; Babji, Y; Kondaiah, N
2008-12-01
A study was carried out to evaluate the antioxidant potential of pomegranate juice (PJ), rind powder extract (RP) and butylated hydroxyl toluene (BHT) in cooked chicken patties during refrigerated storage. Freshly minced chicken meats were assigned to one of the following four treatments: control (meat treated with no antioxidants); 10mg equivalent PJ phenolics per 100g meat; 10mg equivalent RP phenolics per 100g meat; 10mg BHT per 100g meat. The patties formed from the minced meats were grilled for 20min and stored under aerobically at 4°C for 15 days. Total phenolic content (as tannic acid equivalent) significantly (PBHT, PJ and RP patties, respectively. The RP treatment substantially inhibited (PBHT treatment. The PJ or RP at a level of 10mg equivalent phenolics/100g meat would be sufficient to protect chicken patties against oxidative rancidity for periods longer than the most commonly used synthetic antioxidant like BHT.
Effect of penicillin on fatty acid synthesis and excretion in Streptococcus mutans BHT
Energy Technology Data Exchange (ETDEWEB)
Brissette, J.L.; Pieringer, R.A.
1985-03-01
Treatment of exponentially growing cultures of Streptococcus mutans BHT with growth-inhibitory concentrations (0.2 microgram/ml) of benzylpenicillin stimulates the incorporation of (2-/sup 14/C) acetate into lipids excreted by the cells by as much as 69-fold, but does not change the amount of /sup 14/C incorporated into intracellular lipids. At this concentration of penicillin cellular lysis does not occur. The radioactive label is incorporated exclusively into the fatty acid moieties of the glycerolipids. During a 4-hr incubation in the presence of penicillin, the extracellular fatty acid ester concentration increases 1.5 fold, even though there is no growth or cellular lysis. An indication of the relative rate of fatty acid synthesis was most readily obtained by placing S. mutans BHT in a buffer containing /sup 14/C-acetate. Under these nongrowing conditions free fatty acids are the only lipids labeled, a factor which simplifies the assay. The addition of glycerol to the buffer causes all of the nonesterified fatty acids to be incorporated into glycerolipid. The cells excrete much of the lipid whether glycerol is present or not. Addition of penicillin to the nongrowth supporting buffer system does not stimulate the incorporation of (/sup 14/C)-acetate into fatty acids.
Crystal growth and properties of NLO optical crystal - Butylated Hydroxy Toluene (BHT)
Raja, R.; Seshadri, S.; Gnanasambandan, T.; Saravanan, R. R.
2015-03-01
Crystallographic, experimental and theoretical density functional theory (DFT) of Butylated Hydroxy Toluene (BHT) are investigated. The grown crystals were identified by single crystal X-ray analysis. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of BHT is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The molecular electrostatic potential (MESP) mapping is very useful in the investigation of the molecular structure with its physiochemical property relationship. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV-Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals. The grown crystals were characterized by measuring their thermal properties by Differential Thermal Analysis (DTA) and Thermo Gravimetric Analysis (TGA) measurements.
Li, Zhiyong; Cheng, He; Li, Junyu; Hao, Jinkun; Zhang, Li; Hammouda, Boualem; Han, Charles C
2011-06-23
Author: Because of the closed-loop phase diagram of tetrahydrofuran (THF)-water mixture, THF aqueous solution naturally exhibits concentration fluctuations near the phase boundary. Besides the fast mode induced by concentration fluctuations, the 4.5% mole fraction THF aqueous solution is also characterized by a slow mode. The existence of a trace amount of butylhydroxytoluene (BHT) antioxidant in commercial THF strongly influences the slow mode in 4.5% mole fraction THF aqueous solution. A core-shell structure with a BHT core and a shell made from THF-rich THF-D(2)O mixture was identified by the combination of dynamic laser light scattering (DLS) and small-angle neutron scattering (SANS). BHT is hydrophobic, stabilized by a THF-rich domain in THF aqueous solution and acts as a tracer to make the large-scale structure (slow mode) "visible" through SANS because of its larger contrast with the solvent. In contrast, this large-scale structure was almost not detectable by SANS when BHT was removed from the THF-D(2)O mixture. Combined UV-vis, DLS, and static light scattering (SLS) indicated that slow-moving objects do exist and that their sizes almost do not change, but their concentration decreases to a small but nonzero value at the infinite dilution limit. The origin of the elusive large-scale structure at zero BHT concentration is still not clear, but it might be associated with some hydrophobic impurities or nanobubbles. However, a polydisperse sphere model of ∼8.5% mole fraction THF-D(2)O mixture can fit the structure with a radius of ∼100 nm, which gives the temperature-dependent low-q SANS profiles of 4.5% mole fraction THF aqueous solution at zero BHT concentration.
Modifications of Einstein's theory of gravity at large distances
2015-01-01
In the last few years modified gravity theories have been proposed as extensions of Einstein's theory of gravity. Their main motivation is to explain the latest cosmological and astrophysical data on dark energy and dark matter. The study of general relativity at small scales has already produced important results (cf e.g. LNP 863 Quantum Gravity and Quantum Cosmology) while its study at large scales is challenging because recent and upcoming observational results will provide important information on the validity of these modified theories. In this volume, various aspects of modified gravity at large scales will be discussed: high-curvature gravity theories; general scalar-tensor theories; Galileon theories and their cosmological applications; F(R) gravity theories; massive, new massive and topologically massive gravity; Chern-Simons modifications of general relativity (including holographic variants) and higher-spin gravity theories, to name but a few of the most important recent developments. Edite...
Global monopoles in dilaton gravity
Dando, Owen; Gregory, Ruth
1998-04-01
We analyse the gravitational field of a global monopole within the context of low-energy string gravity, allowing for an arbitrary coupling of the monopole fields to the dilaton. Both massive and massless dilatons are considered. We find that, for a massless dilaton, the spacetime is generically singular, whereas when the dilaton is massive, the monopole generically induces a long-range dilaton cloud. We compare and contrast these results with the literature.
Global Monopoles in Dilaton Gravity
Dando, O; Dando, Owen; Gregory, Ruth
1998-01-01
We analyse the gravitational field of a global monopole within the context of low energy string gravity, allowing for an arbitrary coupling of the monopole fields to the dilaton. Both massive and massless dilatons are considered. We find that, for a massless dilaton, the spacetime is generically singular, whereas when the dilaton is massive, the monopole generically induces a long range dilaton cloud. We compare and contrast these results with the literature.
Maegawa, Tomohiro; Koutani, Yasuyuki; Otake, Kazuki; Fujioka, Hiromichi
2013-04-05
A mild and efficient method for formation of methylene acetals from 1,2- and 1,3-diols using methoxymethylphenylsulfide, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), and dibutylhydroxytoluene (BHT) is described. The use of BHT in this process suppresses side reactions and enables high-yielding formation of methylene acetals of various diols, including carbohydrate-type substrates.
Modesto, Leonardo
2013-01-01
We hereby present a class of multidimensional higher derivative theories of gravity that realizes an ultraviolet completion of Einstein general relativity. This class is marked by a "non-polynomal" entire function (form factor), which averts extra degrees of freedom (including ghosts) and improves the high energy behavior of the loop amplitudes. By power counting arguments, it is proved that the theory is super-renormalizable in any dimension, i.e. only one-loop divergences survive. Furthermore, in odd dimensions there are no counter terms for pure gravity and the theory turns out to be "finite." Finally, considering the infinite tower of massive states coming from dimensional reduction, quantum gravity is finite in even dimension as well.
Lu, H F; Wu, H C; Chang, W C; Chung, J G
1999-01-01
Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were used to determine any effects on the N-acetyltransferase (NAT) activity in rat whole blood and white blood cells as measured by high performance liquid chromatography assay for the amounts of N-acetyl-2-aminofluorene (AAF) and 2-aminofluorene (AF). Two assay systems were performed, one with cellular cytosols, the other with intact white blood cells. The NAT activity in the whole blood and white blood cell cytosols was suppressed by BHA and BHT in a dose-dependent manner, i.e. the higher the concentrations of BHA and BHT, the higher the inhibition of NAT activity. Time-course experiments showed that NAT activity measured from the intact white blood cells was inhibited by BHA and BHT up to 24 h. The results suggest that BHA and BHT suppressed AF acetylation in rat blood with intact white blood cells.
Bakeeva, L E; Zamyatnina, V A; Shorning, B Y; Aleksandrushkina, N I; Vanyushin, B F
2001-08-01
Ionol (BHT), a compound having antioxidant activity, at concentrations in the range 1-50 mg/liter (0.45 x 10(-5)-2.27 x 10(-4) M), inhibits growth of etiolated wheat seedlings, changes the morphology of their organs, prolongs the coleoptile life span, and prevents the appearance of specific features of aging and apoptosis in plants. In particular, BHT prevents the age-dependent decrease in total DNA content, apoptotic internucleosomal fragmentation of nuclear DNA, appearance in the cell vacuole of specific vesicles with active mitochondria intensively producing mtDNA, and formation of heavy mitochondrial DNA rho = 1.718 g/cm3) in coleoptiles of etiolated wheat seedlings. BHT induces large structural changes in the organization of all cellular organelles (nucleus, mitochondria, plastids, Golgi apparatus, endocytoplasmic reticulum) and the formation of new unusual membrane structures in the cytoplasm. BHT distorts the division of nuclei and cells, and this results in the appearance of multi-bladed polyploid nuclei and multinuclear cells. In roots of etiolated wheat seedlings, BHT induces intensive synthesis of pigments, presumably carotenoids, and the differentiation of plastids with formation of chloro- or chromoplasts. The observed multiple effects of BHT are due to its antioxidative properties (the structural BHT analog 3,5-di-tert-butyltoluene is physiologically inert; it has no effect similar to that of BHT). Therefore, the reactive oxygen species (ROS) controlled by BHT seem to trigger apoptosis and the structural reorganization of the cytoplasm in the apoptotic cell with formation of specific vacuolar vesicles that contain active mitochondria intensively producing mtDNA. Thus, the inactivation of ROS by BHT may be responsible for the observed changes in the structure of all the mentioned cellular organelles. This corresponds to the idea that ROS control apoptosis and mitosis including formation of cell wall, and they are powerful secondary messengers that
Gaia16bhp, Gaia16bhq, Gaia16bht and Gaia16bhj transients confirmed by Mercator/Maia imaging
Blanco-Cuaresma, S.; Semaan, T.; Roelens, M.; Palaversa, L.; Mowlavi, N.; Eyer, L.
2016-09-01
We report confirmation of Gaia Science Alerts transients Gaia16bhp, Gaia16bhq, Gaia16bht and Gaia16bhj. Images were obtained in G and R bands of the Maia instrument mounted to the Flemish 1.2m Mercator telescope at Roque de los Muchachos observatory, La Palma, Canary Islands, Spain, on 2016 September 18-19.
Clean up procedure (GPC) voor de GC bepaling van de antioxidanten BHA, BHT en TBHQ in botervet
Slangen, J.; Traag, W.; Kamp, van der H.; Hollman, P.
1987-01-01
Voor het opstellen van een normvoorschrift voor de bepaling van de antioxydanten BHA, BHT en TBHQ in botervet worden door werkgroep E43 van de "International Dairy Federation" methoden geëvalueerd. Uitgangspunt voor deze norm is de gaschromatografische bepaling beschreven in ISO 6463-1982. De wens
Criado, Susana; Allevi, Carolina; Ceballos, Claudio; García, Norman A
2007-01-01
Visible-light photo-irradiation of the commercial phenolic antioxidants (PhAs) butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), in the presence of vitamin B2 (riboflavin, Rf), in methanolic solutions and under aerobic conditions, results in the photo-oxidation of the PhAs. The synthetic dye photosensitiser Rose Bengal was also employed for auxiliary experiments. With concentrations of riboflavin and PhAs of ca. 0.02 mM and BHT in a competitive fashion with dissolved ground state triplet oxygen. From the quenching of 3Rf*, the semireduced form of the pigment is generated through an electron transfer process from BHT, with the subsequent production of superoxide anion radical (O2*-) by reaction with dissolved molecular oxygen. In parallel, the species singlet molecular oxygen, O2(1delta(g)), is also generated. Both reactive oxygen species produce the photodegradation of BHT. In the case of BHA, the lack of any effect exerted by superoxide dismutase drives out a significant participation of a O2(*-)-mediated mechanism. BHA mainly interacts with O2(1delta(g)) and exhibits a desirable property as an antioxidant--a relatively high capacity for O2(1delta(g)) de-activation and a low photodegradation efficiency by the oxidative species. Electrochemical determinations support the proposed photodegradative mechanism.
Devatkal, Suresh K; Kumboj, Ritu; Paul, Devosmita
2014-02-01
Antioxidant properties of banana (Musa paradisiaca) and Sapodilla/Chikoo (Manilkara zapota) peel extracts in chicken patties were evaluated. Four treatments viz., I. Control (meat + 2% salt), II.BHT (meat + 2% salt + 0.1% BHT), III. BPE (meat + 2% salt + 2% banana peel extract) and IV. SPE (meat + 2% salt + 2% sapodilla/chikoo peel extract) were compared for changes in colour and lipid oxidation during 8 days refrigerated storage (4 ± °C). The average phenolic content was 550.2 and 550.8 mg gallic acid equivalent per 10 g peel in BPE and SPE respectively. Free radical scavenging activity was 66.9 and 67.8% in BPE and SPE respectively. Banana peel extract had significantly (P BHT (387.7%), BPE (370.6%) and SPE (383.7%). Both synthetic antioxidants and natural extracts significantly decreased the TBARS. The average decrease in TBARS values during 8 days of storage was 56.8%, 38.3% and 37.2% values in BHT, BPE and SPE treatments respectively. Therefore, it was concluded that water extracts obtained from banana and sapodilla peels could be explored as natural antioxidants in poultry meat and meat products.
Soubra, L; Sarkis, D; Hilan, C; Verger, Ph
2007-02-01
The acceptable daily intake (ADI) for a considered chemical is by definition the amount of that substance which can be ingested every day during the life time without appreciable health risk. The theoretical risk of exceeding the ADI for benzoates, sulphites, butylhydroxyanisol (BHA) and butylhydroxytoluen (BHT) has often been examined on the basis of worst case scenario. The aim of this paper is to assess the actual intake of the food additives listed above for a group of the Lebanese population (students aged between 9 and 18 years old) likely to be highly exposed to food additives through the consumption of processed foods. Dietary exposure was obtained by combining food consumption data with food additives levels determined by chemical analysis. Food products available in Lebanon and containing added benzoates, sulphites, BHA and BHT were identified. Overall 420 samples of foods and beverages were analysed. The determination of food additives residue levels was carried out according to the official methods adopted in "Lebanese Institute for agronomic research" (IRAL) on food as consumed. The acceptable daily intake (ADI) could be exceeded for sulphites and BHT by a fraction of the population, in particular within children of 9-13 years old. Among all food additive-containing foods, the highest contributors were: soft drinks to benzoates intake, nuts and canned juices to sulphites intake, bread and biscuits to BHA intake and chewing gum to BHT intake.
Nine-week detection of six genotoxic lung carcinogens using the rasH2/BHT mouse model.
Umemura, Takashi; Kodama, Yukio; Nishikawa, Akiyoshi; Hioki, Kyoji; Nomura, Tatsuji; Kanki, Keita; Kuroiwa, Yuichi; Ishii, Yuji; Kurokawa, Yuji; Hirose, Masao
2006-01-18
A 9-week in vivo rasH2/butylhydroxytoluene (BHT) model for the detection of genotoxic lung carcinogens was validated, using six potent positive test compounds, dimethylnitrosamine (DMN; 15 mg/kg, i.p.), diethylnitrosamine (DEN; 100 mg/kg, i.p.), ethylnitrosourea (ENU; 120 mg/kg, i.p.), 3-methylcholanthrene (MC; 100 mg/kg, i.p.), 7,12-dimethylbenz(a)anthracene (DMBA; 5 mg/kg, i.g.) and benzo(a)pyrene (B(a)P; 80 mg/kg, i.p.), each given to rasH2 mice of both genders by single administration for initiation followed by promoter BHT treatment. Statistically significant increase in the incidence and multiplicity of lung tumors was observed in rasH2 mice treated with BHT following exposure to all of the carcinogens tested. The data overall suggest the rasH2/BHT model to be a powerful screening tool for genotoxic lung carcinogens.
A proposal to follow up costs using the connection between EDH (destinations) and BHT (activities)
Jenssen, B W
1998-01-01
External constraints like budget for material and personnel may be set outside the Division. However, the Division may measure the main output of its activities to justify the need for its resources and to maintain an optimal allocation of the resources within the Division. Before using resources (material + personnel = money) the expected output/performance should be defined. This will help us to allocate the resources where best needed and also to justify the need for resources. Possible deviations of expected output/performance may be caused by factors that should be known in advance or could not be known in advance. Deviations should be regarded as something positive - a possibility for a continuous improvement. This paper tries to show how one may use one available dimension in the financial system (EDH-BHT) to track deviations and follow up the costs.
Three-dimensional tricritical gravity
Bergshoeff, Eric A.; de Haan, Sjoerd; Merbis, Wout; Rosseel, Jan; Zojer, Thomas
2012-01-01
We consider a class of parity-even, six-derivative gravity theories in three dimensions. After linearizing around anti-de Sitter space, the theories have one massless and two massive graviton solutions for generic values of the parameters. At a special, so-called tricritical, point in parameter spac
Bianchi, Eugenio
The following sections are included: * Introduction * Topological Field Theory and Gravity * Classical Spinfoam Gravity: Degrees of Freedom and Foams * Unitary Representations of the Rotation and the Lorentz Group * Boundary Variables and the Loop Quantum Gravity Hilbert Space * Spinfoam Partition Function and the Vertex Amplitude * Cellular Quantum Geometry: A Single Atom of Space * Cellular Quantum Geometry: Coherent Spin-networks * Vertex-amplitude Asymptotics and Regge Gravity * Reconstructing a Semiclassical Spacetime * Conclusions * References
Thompson, J A; Carlson, T J; Sun, Y; Dwyer-Nield, L D; Malkinson, A M
2001-03-07
Chronic treatment of BALB and GRS mice with BHT (2,6-di-tert-butyl-4-methylphenol) following a single urethane injection increases lung tumor multiplicity, but this does not occur in CXB4 mice. Previous data suggest that promotion requires the conversion of BHT to a tert-butyl-hydroxylated metabolite (BHTOH) in lung and the subsequent oxidation of this species to an electrophilic quinone methide. To obtain additional evidence for the importance of quinone methide formation, structural analogs that form less reactive quinone methides were tested and found to lack promoting activity in BHT-responsive mice. The possibility that promotion-unresponsive strains are unable to form BHTOH was tested by substituting this compound for BHT in the promotion protocol using CXB4 mice. No promotion occurred, and in-vitro work demonstrated that CXB4 mice are, in fact, capable of producing BHTOH and its quinone methide, albeit in smaller quantities. Incubations with BALB lung microsomes and radiolabeled substrates confirmed that more covalent binding to protein occurs with BHTOH than with BHT and, in addition, BHTOH quinone methide is considerably more toxic to mouse lung epithelial cells than BHT quinone methide. These data are consistent with the hypothesis that a two-step oxidation process, i.e. hydroxylation and quinone methide formation, is required for the promotion of mouse lung tumors by BHT.
Cosmological tests of modified gravity
Koyama, Kazuya
2016-04-01
We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein’s theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard Λ CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.
Cosmological tests of modified gravity.
Koyama, Kazuya
2016-04-01
We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.
Giribet, Gaston
2014-01-01
Minimal Massive Gravity (MMG) is an extension of three-dimensional Topologically Massive Gravity that, when formulated about Anti-de Sitter space, accomplishes to solve the tension between bulk and boundary unitarity that other models in three dimensions suffer from. We study this theory at the chiral point, i.e. at the point of the parameter space where one of the central charges of the dual conformal field theory vanishes. We investigate the non-linear regime of the theory, meaning that we study exact solutions to the MMG field equations that are not Einstein manifolds. We exhibit a large class of solutions of this type, which behave asymptotically in different manners. In particular, we find analytic solutions that represent two-parameter deformations of extremal Banados-Teitelboim-Zanelli (BTZ) black holes. These geometries behave asymptotically as solutions of the so-called Log Gravity, and, despite the weakened falling-off close to the boundary, they have finite mass and finite angular momentum, which w...
Giribet, Gaston; Vásquez, Yerko
2015-01-01
Minimal massive gravity (MMG) is an extension of three-dimensional topologically massive gravity that, when formulated about anti-de Sitter space, accomplishes solving the tension between bulk and boundary unitarity that other models in three dimensions suffer from. We study this theory at the chiral point, i.e. at the point of the parameter space where one of the central charges of the dual conformal field theory vanishes. We investigate the nonlinear regime of the theory, meaning that we study exact solutions to the MMG field equations that are not Einstein manifolds. We exhibit a large class of solutions of this type, which behave asymptotically in different manners. In particular, we find analytic solutions that represent two-parameter deformations of extremal Bañados-Teitelboim-Zanelli black holes. These geometries behave asymptotically as solutions of the so-called log gravity, and, despite the weakened falling off close to the boundary, they have finite mass and finite angular momentum, which we compute. We also find time-dependent deformations of Bañados-Teitelboim-Zanelli that obey Brown-Henneaux asymptotic boundary conditions. The existence of such solutions shows that the Birkhoff theorem does not hold in MMG at the chiral point. Other peculiar features of the theory at the chiral point, such as the degeneracy it exhibits in the decoupling limit, are discussed.
Special Gravity as Alternatives for Interacting Massless Gravitons
Bai, Dong
2016-01-01
Special gravity, first discussed by Wald \\cite{Wald:1986bj} decades ago, is a novel class of theories for interacting massless gravitons in Minkowski spacetime. It respects gauge invariance, but not general covariance, which is drastically different from Einstein's gravity and many of its modifications. In this note, we study properties of special gravity, revealing its connections with asymptotic causality, S-matrix program, non-renormalization, massive gravity and emergent gravitons in condensed matter systems.
DEFF Research Database (Denmark)
Guldborg, Merethe
1981-01-01
-proposed method, and an official French method. After extraction, the compounds are detected by TLC. Being a qualitative method the probability of obtaining correct results is a measure of the goodness of the method, and the study examines the influence on the probability of the following 3 factors: type......A method for the qualitative detection of antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), the gallates and nordihydroguajaretic acid (NDGA) in bakery products and fat has been tested in a collaborative study. The method is similar to a IUPAC-method, an EEC...... of antioxidant, type of food, and concentration of antioxidant. From the study is was concluded that the method worked quite well for BHA, with a detection limit about 15 mg/kg, whereas it worked badly for BHT, the detection limit being higher than 30 mg/kg. For the gallates and NDGA the detection limit was 30...
Movileanu, Iulia; Núñez de González, Máryuri T; Hafley, Brian; Miller, Rhonda K; Keeton, Jimmy T
2013-01-01
Fresh ground beef patties with (1) no antioxidant (control), (2) 0.02% butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT), (3) 3% dried plum puree, or (4) 0.25% rosemary extract were aerobically packaged, irradiated at target doses of 0, 1.5, or 2.0 kGy (1.7 and 2.3 kGy actual doses), and stored at 4°C. The samples were evaluated for lipid oxidation on 0, 3, 7, 14, 21, and 28 days of storage after irradiation. When compared to the control, all antioxidant treatments were effective in retarding (P 0.05) as BHA/BHT in irradiated and nonirradiated beef patties, followed by the dried plum puree treatment. Irradiation increased TBARs values, but no differences were noted in oxidation between irradiation dose levels.
Institute of Scientific and Technical Information of China (English)
WU Ning
2006-01-01
It is well known that energy-momentum is the source of gravitational field. For a long time, it is generally believed that only stars with huge masses can generate strong gravitational field. Based on the unified theory of gravitational interactions and electromagnetic interactions, a new mechanism of the generation of gravitational field is studied. According to this mechanism, in some special conditions, electromagnetic energy can be directly converted into gravitational energy, and strong gravitational field can be generated without massive stars. Gravity impulse found in experiments is generated by this mechanism.
Directory of Open Access Journals (Sweden)
Racanicci AMC
2000-01-01
Full Text Available Este estudo foi desenvolvido com a finalidade monitorar a qualidade da farinha de carne e ossos (FCO, durante o armazenamento prolongado (10 semanas, e avaliar os efeitos da adição do BHT (500mg/kg a esta farinha. Um lote fresco de FCO (41,12% PB e 9,14% EE foi dividido em seis partes iguais, sendo uma não tratada (CONTROLE e as demais tratadas com BHT em diferentes tempos de armazenamento (nos dias 0, 7, 14, 21 e 28: BHT/0, BHT/7, BHT/14, BHT/21 e BHT/28, respectivamente. As FCO foram armazenadas em ambiente diariamente monitorado e sua qualidade foi avaliada por amostragens semanais, com determinação do índice de peróxidos, cujo nível máximo obtido foi de aproximadamente 80meq/kg (CONTROLE. A partir da 4ª semana de armazenamento, foi conduzido um experimento com frangos de corte alimentados por 42 dias com rações à base de milho e farelo de soja, contendo cerca de 4% das FCO armazenadas. Foram utilizados 1.440 pintos de um dia, machos, distribuídos num delineamento em blocos casualizados, com 6 tratamentos e 6 repetições. Os resultados médios obtidos para peso vivo, ganho de peso, consumo de ração, conversão alimentar, mortalidade e refugagem e fator de produção foram submetidos à análise da variância e as médias dos tratamentos foram comparadas ao CONTROLE através do teste de Dunnett. As variáveis estudadas, em geral, não foram afetadas pelos tratamentos (p>0,05, indicando que, neste estudo, o uso da FCO oxidada ou das FCO protegidas pelo BHT, não influenciaram o desempenho das aves.
Rowe, C W; Pohlman, F W; Brown, A H; Baublits, R T; Johnson, Z B
2009-01-01
USDA Select striploins (n = 20) were cut into thirds (anterior, medial, and posterior) and randomly assigned to 1 of 6 treatments. Treatments included: (1) control (C); (2) 0.006% BHA (butylated hydroxyl anisole)/BHT (butylated hydroxytoluene) (70%/30%) (BB); (3) 0.4% trisodiumphosphate (CT); (4) 0.4% sodiumtripolyphosphate with 0.5% salt (BH); (5) sodiumtripolyphosphate, 0.5% salt, and 0.006% BHA/BHT (70%/30%) (SB); (6) 0.2% sodiumtripolyphosphate, 0.2% trisodiumphosphate, and 0.5% salt (STB). Muscle sections were injected to 110% (10% pump) of their weight with their respective treatments. Inclusion of BHA/BHT allowed for lower mean oxidation values. Regardless of phosphate type, muscles treated with both phosphate and salt had lower retail purge (P < 0.05). Sensory panelists rated (P < 0.05) STB, SB, and BH to be juicier than all other treatments. These data suggest that inclusion of both salt and phosphate can enhance palatability, lower cook loss, and retail purge.
BHT的电化学性质研究%Study on Electrochemistry Nature of BHT
Institute of Scientific and Technical Information of China (English)
邓鹏; 巩东营; 李桂龙; 薛文通
2013-01-01
油脂在热、光、重金属和辐射等因素下,极易发生氧化而产生酸败,为此,需要在油脂中添加不同种类的抗氧化剂延缓氧化,达到延长货架期的目的.2,6-二丁基羟基甲苯(BHT)是油脂中常用的抗氧化剂.本文基于抗氧化剂BHT的介电性质,探讨了BHT的电化学行为.研究中以Nafion修饰玻碳电极作为工作电极、以LiClO4乙腈溶液作为电解质,采用循环伏安扫描测定法(CSV),从BHT的电化学性质方面对其抗氧化机理进行了阐述,且得到了在1.65×10-5-1.65×10-4mol/L范围内BHT加入量与氧化峰电流呈良好的线性关系,以探讨建立一种新型的油脂中抗氧化剂添加量快速测定方法.
Sun, Ying-Ying; Xie, Yun-Fei; Wang, He-Ya; Qian, He; Yao, Wei-Rong
2012-11-01
2,6-Di-t-butyl-p-hydroxytoluene (BHT), a common antioxidant, has been implicated in oil foods and food packaging materials as a substance that could migrate into the food supply chain and cause suppression of human respiratory enzymes. In this study, BHT solutions in different solvents were measured by surface enhanced Raman spectroscopy (SERS) in combination with SERS-active substrates: gold colloidal nanoparticles. The limit of detection of BHT can reach the level of 10 μg/mL with SERS in methanol. The Raman peak at 766 cm-1 was used as the index of quantitative analysis and the correlation coefficient was 0.9761. These results demonstrated the applicability of utilizing SERS to detect low concentrations of BHT. By comparing the features of SERS peaks with the density functional theory (DFT)-calculated Raman spectrum, the adsorption behavior of BHT on the surface of gold nanoparticles was analyzed in detail and it was determined that the dominant contribution to the SERS signal in this case should be the electromagnetic enhancement mechanism. A charge-transfer mechanism also contributed to the SERS signal for BHT adsorbed on gold nanoparticles by the Phsbnd O(H) (Ph = phenyl) coalescent format.
Energy Technology Data Exchange (ETDEWEB)
Healey, D.L. [Geological Survey, Denver, CO (USA)
1983-12-31
A large density contrast exists between the Paleozoic rocks (including the rocks of Climax stock) and less dense, Tertiary volcanic rocks and alluvium. This density contrast ranges widely, and herein for interpretive purposes, is assumed to average 0.85 Mg/m{sup 3} (megagrams per cubic meter). The large density contrast makes the gravity method a useful tool with which to study the interface between these rock types. However, little or no density contrast is discernible between the sedimentary Paleozoic rocks that surround the Climax stock and the intrusive rocks of the stock itself. Therefore the gravity method can not be used to define the configuration of the stock. Gravity highs coincide with outcrops of the dense Paleozoic rocks, and gravity lows overlie less-dense Tertiary volcanic rocks and Quaternary alluvium. The positions of three major faults (Boundary, Yucca, and Butte faults) are defined by steep gravity gradients. West of the Climax stock, the Tippinip fault has juxtaposed Paleozoic rocks of similar density, and consequently, has no expression in the gravity data in that area. The gravity station spacing, across Oak Spring Butte, is not sufficient to adequately define any gravity expression of the Tippinip fault. 18 refs., 5 figs.
Antioxidant effect of BHT and vitamin E on canola oil%抗氧化剂BHT和维生素E对菜籽油的抗氧化研究
Institute of Scientific and Technical Information of China (English)
汤务霞; 陈明涛; 阙晓莉
2011-01-01
油脂及富含油脂的食品易发生氧化酸败,为了防止其氧化最常见的方法是加入抗氧化剂.BHT和维生素E是两种常见的抗氧化剂.本文以酸价(AV)和过氧化值(POV)为指标,研究了单独使用BHT以及BHT和维生素E(VE)复配使用在(60±1)℃加速氧化下对菜籽油贮存稳定性的影响.研究结果表明:(1)在单独使用BHT作为抗氧化剂时,BHT对菜籽油有一定抗氧化性,其添加量为0.2‰时抗氧化效果最好,其抗氧化效果顺序为0.20‰＞0.05‰＞0.25‰ ＞0.15‰＞0.01‰；(2)在BHT和VE复配使用时比单独使用BHT效果好,其最佳配比浓度为0.10‰BHT和0.10‰VE,其抗氧化作用效果的顺序为0.10‰ BHT+0.10‰ VE＞0.15‰BHT +0.05‰VE＞0.10‰BHT +0.05‰VE ＞0.05‰BHT+0.05‰VE＞0.05‰BHT+0.10‰ VE＞0.10‰ BHT +0.15‰VE＞0.05‰BHT +0.15‰VE ＞0.15‰ BHT +0.15‰ VE ＞0.15‰ BHT+0.10‰ VE.%Lipids and oil - riched foods are easy oxidative and rancid. BHT and vitaminE (VE) are two common an-tioxidants in preventing food oxidation. According to the acid value (AV) and peroxide value (POV), antioxidantive effects of BHT alone and combination of BHT and VE on the storage stability of Canola oil under accelerated oxidative condition (60±l)t were studied. The results showed that; (1) when BHT used alone, the best concentration to prevent oxidation was 0. 20‰, and the order of BHA content on antioxidation was 0. 20‰ >0. 05‰ >0. 25‰ >0. I5‰ >0. 01‰; (2) when BHT and VE used at the same time, their antioxidantive effect was superior to BHT alone and the best combination was 0. 10 BHT and 0. 10 VE, and the order of antioxidantive effect was 0. 10‰ BHT +0. 10‰ VE >0. 15‰ BHT +0. 05‰ VE > 0. 10‰ BHT +0.05‰ VE >0. 05‰ BHT +0. 05‰ VE >0. 05‰ BHT +0. 10‰ VE >0. 10‰ BHT +0.15‰ VE >0. 05‰ BHT +0. \\5‰> VE >0. 15‰ BHT +0. 15‰ VE >0. 15‰ BHT +0.10‰ VE.
Mashhoon, Bahram
2017-01-01
Relativity theory is based on a postulate of locality, which means that the past history of the observer is not directly taken into account. This book argues that the past history should be taken into account. In this way, nonlocality---in the sense of history dependence---is introduced into relativity theory. The deep connection between inertia and gravitation suggests that gravity could be nonlocal, and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein's theory of gravitation has recently been developed. A significant consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. According to nonlocal gravity theory, what astronomers attribute to dark matter should instead be due to the nonlocality of gravitation. Nonlocality dominates on the scale of galaxies and beyond. Memory fades with time; therefore, the nonlocal aspect of gravity becomes wea...
Clément, Gilles
2007-01-01
Protecting the health, safety, and performance of exploration-class mission crews against the physiological deconditioning resulting from long-term weightlessness during transit and long-term reduced gravity during surface operations will require effective, multi-system countermeasures. Artificial gravity, which would replace terrestrial gravity with inertial forces generated by rotating the transit vehicle or by short-radius human centrifuge devices within the transit vehicle or surface habitat, has long been considered a potential solution. However, despite its attractiveness as an efficient
Superrenormalizable quantum gravity with complex ghosts
Modesto, Leonardo
2015-01-01
We suggest and briefly review a new sort of superrenormalizable models of higher derivative quantum gravity. The higher derivative terms in the action can be introduced in such a way that all the unphysical massive states have complex poles. According to the literature on Lee-Wick quantization, in this case the theory can be formulated as unitary, since all massive ghosts-like degrees of freedom are unstable.
Superrenormalizable quantum gravity with complex ghosts
Directory of Open Access Journals (Sweden)
Leonardo Modesto
2016-04-01
Full Text Available We suggest and briefly review a new sort of superrenormalizable models of higher derivative quantum gravity. The higher derivative terms in the action can be introduced in such a way that all the unphysical massive states have complex poles. According to the literature on Lee–Wick quantization, in this case the theory can be formulated as unitary, since all massive ghosts-like degrees of freedom are unstable.
Lujan, Richard E.
2001-01-01
A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.
Fritts, David
1987-02-01
Gravity waves contributed to the establishment of the thermal structure, small scale (80 to 100 km) fluctuations in velocity (50 to 80 m/sec) and density (20 to 30%, 0 to peak). Dominant gravity wave spectrum in the middle atmosphere: x-scale, less than 100 km; z-scale, greater than 10 km; t-scale, less than 2 hr. Theorists are beginning to understand middle atmosphere motions. There are two classes: Planetary waves and equatorial motions, gravity waves and tidal motions. The former give rise to variability at large scales, which may alter apparent mean structure. Effects include density and velocity fluctuations, induced mean motions, and stratospheric warmings which lead to the breakup of the polar vortex and cooling of the mesosphere. On this scale are also equatorial quasi-biennial and semi-annual oscillations. Gravity wave and tidal motions produce large rms fluctuations in density and velocity. The magnitude of the density fluctuations compared to the mean density is of the order of the vertical wavelength, which grows with height. Relative density fluctuations are less than, or of the order of 30% below the mesopause. Such motions may cause significant and variable convection, and wind shear. There is a strong seasonal variation in gravity wave amplitude. Additional observations are needed to address and quantify mean and fluctuation statistics of both density and mean velocity, variability of the mean and fluctuations, and to identify dominant gravity wave scales and sources as well as causes of variability, both temporal and geographic.
Pro-oxidant and anti-oxidant mechanism(s) of BHT and beta-carotene in photocarcinogenesis.
Black, Homer S
2002-04-01
An hypothesis for the role of free radicals in cancer was elaborated by D. Harman in 1962 who suggested that it might be possible to reduce the extent of damage caused by free radicals through three dietary changes: (i) caloric reduction, i.e., lowering the level of free radical reactions arising in the course of normal metabolism; (ii) minimize dietary components that tend to increase the level of free radical reactions (e.g., polyunsaturated fats); and (iii) supplement the diet with one or more free radical reaction inhibitors (anti-oxidants). With respect to (ii) and (iii), lipid peroxidation exemplifies the type of chain reaction initiated by free radicals, with unsaturated fatty acids being the primary center of free radical attack. Anti-oxidants act as free radical scavengers and are able to terminate these reactions. Indeed, the phenolic anti-oxidant butylated hydroxytoluene (BHT), and the carotenoid beta-carotene, have both been shown to influence photocarcinogenesis, although the lack of correlation between physicochemical parameters and pathophysiological responses is apparent in both instances. The bimolecular rate constant for reaction of BHT with model peroxyl radicals is low while beta-carotene is highly reactive. However, both are able to efficiently inhibit lipid peroxidation reactions in biological membranes. Indeed, the influence of photocarcinogenesis by both BHT and beta-carotene is diminished as the level of dietary fat decreases, pointing to the involvement of lipid peroxidative reactions. Nevertheless, the mode of action of BHT in inhibiting photocarcinogenesis appears to be related to dose-diminution resulting from an increased spectral absorbance of the stratum corneum. On the other hand, beta-carotene has no such effect and may actually exacerbate photocarcinogenesis under certain dietary conditions. This paradox points to the complex relationship between chemical mechanisms and biological mode of action of anti-oxidants in
Epidemiology of Massive Transfusion
DEFF Research Database (Denmark)
Halmin, Märit; Chiesa, Flaminia; Vasan, Senthil K;
2016-01-01
OBJECTIVE: There is an increasing focus on massive transfusion, but there is a paucity of comprehensive descriptions of the massively transfused patients and their outcomes. The objective of this study is to describe the incidence rate of massive transfusion, patient characteristics, and the mort...
Gilani, A H S
2004-01-01
It is claimed that only one gluon is massless and the other seven gluons are massive. Out of eight gluons, six are colored and two are neutral. Among neutral gluons, one is massless and other one is massive. Massive neutral gluon is heavier than the colored gluons. Gluons can only be predicted by set theory but not by SU(3).
Generalized modified gravity in large extra dimensions
Energy Technology Data Exchange (ETDEWEB)
Aslan, Onder [Department of Physics, Izmir Institute of Technology, IZTECH, TR-35430 Izmir (Turkey); Demir, Durmus A. [Department of Physics, Izmir Institute of Technology, IZTECH, TR-35430 Izmir (Turkey)]. E-mail: demir@physics.iztech.edu.tr
2006-04-20
We discuss effective interactions among brane matter induced by modifications of higher-dimensional Einstein gravity through the replacement of Einstein-Hilbert term with a generic function f(R,R{sub AB}R{sup AB},R{sub ABCD}R{sup ABCD}) of the curvature tensors. We determine gravi-particle spectrum of the theory, and perform a comparative analysis of its predictions with those of the Einstein gravity within Arkani-Hamed-Dvali-Dimopoulos (ADD) setup. We find that this general higher-curvature quantum gravity theory contributes to scatterings among both massive and massless brane matter (in contrast to much simpler generalization of the Einstein gravity, f(R), which influences only the massive matter), and therefore, can be probed via various scattering processes at present and future colliders and directly confronted with the ADD expectations. In addition to collision processes which proceed with tree-level gravi-particle exchange, effective interactions among brane matter are found to exhibit a strong sensitivity to higher-curvature gravity via the gravi-particle loops. Furthermore, particle collisions with missing energy in their final states are found to be sensitive to additional gravi-particles not found in Einstein gravity. In general, road to a correct description of quantum gravity above Fermi energies depends crucially on if collider and other search methods end up with a negative or positive answer for the presence of higher-curvature gravitational interactions.
Forster, A.; Merriam, D.F.; Davis, J.C.
1997-01-01
Large numbers of bottom-hole temperatures (BHTs) and temperatures measured during drill-stem tests (DSTs) are available in areas explored for hydrocarbons, but their usefulness for estimating geothermal gradients and heat-flow density is limited. We investigated a large data set of BHT and DST measurements taken in boreholes in the American Midcontinent, a geologically uniform stable cratonic area, and propose an empirical correction for BHTs based on relationships between BHTs, DSTs, and thermal logs. This empirical correction is compared with similar approaches determined for other areas. The data were analyzed by multivariate statistics prior to the BHT correction to identify anomalous measurements and quantify external influences. Spatial patterns in temperature measurements for major stratigraphic units outline relations to regional structure. Comparision of temperature and structure trend-surface residuals reveals a relationship between temperature highs and local structure highs. The anticlines, developed by continuous but intermittent movement of basement fault blocks in the Late Paleozoic, are subtle features having closures of 10-30 m and contain relatively small hydrocarbon reservoirs. The temperature anomalies of the order of 5-7 ??C may reflect fluids moving upward along fractures and faults, rather than changes in thermal conductivity resulting from different pore fluids. ?? Springer-Verlag 1997.
Yang, Jie; Fang, Congrong; Yang, Dajin
2013-01-01
To develop a method for determining 3 kinds of antioxidants in food in same time with HPLC and GC. Firstly, extracted fat with petroleum ether, then extracted antioxidants with 13 ml methnol, centrifuged, repeated the above procedure twice, combined the extracts, next evaporated to 5 ml, constanted volume to 10 ml, then kepted in freezer (- 1h), lastly, the supernatant injected into high performance liquid chromatography (HPLC) and Gas chromatography (GC) which had been optimized condition. The limits of quantitation for BHA,BHT and TBHQ were 0.002, 0.010 and 0.002g/kg respectively in HPLC, The limits of quantitation for BHA, BHT and TBHQ were 0.003, 0.002 and 0.005 g/kg respectively in GC, The mean recoveries at the two spiked levels were 82.8% - 109.0%. There were no significant difference between HPLC and GC. The method can be used to determine the antioxidants in food accurately and sensitively, the comparative results are constant between liquid and gas chromatography.
Nieva-Echevarría, Bárbara; Goicoechea, Encarnación; Guillén, María D
2017-10-01
The extent of cod liver oil hydrolysis and oxidation during in vitro gastrointestinal digestion was investigated by Proton Nuclear Magnetic Resonance ((1)H NMR) and Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS). These techniques evidenced the degradation of polyunsaturated ω-3 and ω-6 lipids and, for the first time, that of vitamin A, naturally present in cod liver oil. Cis,trans-conjugated dienes associated with hydroperoxides, as well as monoepoxides, cis,trans-2,4-alkadienals, 4-hydroperoxy- and 4-hydroxy-2-alkenals, and several vitamin A derived metabolites were generated. Moreover, the effect of the addition of the synthetic antioxidant 2,6-di-tert-butyl-hydroxytoluene (BHT) at 20 and 800ppm was tackled. Both techniques showed BHT to be efficient in limiting oxidation reactions during digestion, almost inhibiting them at 800ppm. Therefore, the simultaneous intake of antioxidants with cod liver oil should be considered, in order to increase polyunsaturated lipid and vitamin A bioaccessibility and avoid formation of toxic oxidation compounds like oxygenated alpha,beta-unsaturated aldehydes. Copyright © 2017 Elsevier Ltd. All rights reserved.
Schwope, A D; Till, D E; Ehntholt, D J; Sidman, K R; Whelan, R H; Schwartz, P S; Reid, R C
1987-04-01
The most widely used food-wrapping material is low-density polyethylene (LDPE). Food-wrap grades contain antioxidants to minimize degradation during processing and, in the final films, such additives are normally present at levels of several hundred ppm. During use, the antioxidants may migrate into food stored in LDPE wraps. Two typical antioxidants, BHT and Irganox 1010, were radiolabelled to allow accurate analytical measurement of the extent of their migration into foods and food-simulating liquids (FSL). The results show that BHT, a much smaller and more volatile molecule than Irganox 1010, migrates more rapidly into foods, but the differences are less for FSL. In most instances, migration appears to be controlled by diffusion of the antioxidant in the polymer, and the quantity lost can be correlated in a linear fashion with the square root of time. With aqueous FSL, and, presumably aqueous-type foods, however, anomalies result; the migration is often erratic, but is more closely related to time than to the square root of time. A tentative model developed to explain these facts assumes that the antioxidants decompose in aqueous media and the net migration rate is controlled largely by the rate of chemical decomposition. It is also shown that dry foods can be surprisingly effective sinks for antioxidants under typical storage conditions.
Celada, Mariano; Montesinos, Merced
2016-01-01
$BF$ gravity comprises all the formulations of gravity that are based on deformations of $BF$ theory. Such deformations consist of either constraints or potential terms added to the topological $BF$ action that turn some of the gauge degrees of freedom into physical ones, particularly giving rise to general relativity. The $BF$ formulations have provided new and deep insights into many classical and quantum aspects of the gravitational field, setting the foundations for the approach to quantum gravity known as spinfoam models. In this review, we present a self-contained and unified treatment of the $BF$ formulations of $D$-dimensional general relativity and other related models, focusing on the classical aspects of them and including some new results.
Kiefer, Claus
2012-01-01
The search for a quantum theory of the gravitational field is one of the great open problems in theoretical physics. This book presents a self-contained discussion of the concepts, methods and applications that can be expected in such a theory. The two main approaches to its construction - the direct quantisation of Einstein's general theory of relativity and string theory - are covered. Whereas the first attempts to construct a viable theory for the gravitational field alone, string theory assumes that a quantum theory of gravity will be achieved only through a unification of all the interactions. However, both employ the general method of quantization of constrained systems, which is described together with illustrative examples relevant for quantum gravity. There is a detailed presentation of the main approaches employed in quantum general relativity: path-integral quantization, the background-field method and canonical quantum gravity in the metric, connection and loop formulations. The discussion of stri...
Celada, Mariano; González, Diego; Montesinos, Merced
2016-11-01
BF gravity comprises all the formulations of gravity that are based on deformations of BF theory. Such deformations consist of either constraints or potential terms added to the topological BF action that turn some of the gauge degrees of freedom into physical ones, particularly giving rise to general relativity. The BF formulations have provided new and deep insights into many classical and quantum aspects of the gravitational field, setting the foundations for the approach to quantum gravity known as spinfoam models. In this review, we present a self-contained and unified treatment of the BF formulations of D-dimensional general relativity and other related models, focusing on the classical aspects of them and including some new results.
Massive Black Holes and Galaxies
CERN. Geneva
2016-01-01
Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.
Bahrami, M; McMillen, S; Paternostro, M; Ulbricht, H
2015-01-01
What gravitational field is generated by a massive quantum system in a spatial superposition? This is one of the most important questions in modern physics, and after decades of intensive theoretical and experimental research, we still do not know the answer. On the experimental side, the difficulty lies in the fact that gravity is weak and requires large masses to be detectable. But for large masses, it becomes increasingly difficult to generate spatial quantum superpositions, which live sufficiently long to be detected. A delicate balance between opposite quantum and gravitational demands is needed. Here we show that this can be achieved in an optomechanics scenario. We propose an experimental setup, which allows to decide whether the gravitational field generated by a quantum system in a spatial superposition is the superposition of the two alternatives, or not. We estimate the magnitude of the effect and show that it offers good perspectives for observability. Performing the experiment will mark a breakth...
Pipinos, Savas
2010-01-01
This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity…
Pipinos, Savas
2010-01-01
This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity…
Massive motion in Brans-Dicke geometry and beyond
Punzi, Raffaele; Wohlfarth, Mattias N R
2009-01-01
Gravity theories that can be viewed as dynamics for area metric manifolds, for which Brans-Dicke theory presents a recently studied example, require for their physical interpretation the identification of the distinguished curves that serve as the trajectories of light and massive matter. Complementing previous results on the propagation of light, we study effective massive point particle motion. We show that the relevant geometrical structure is a special Finsler norm determined by the area metric, and that massive point particles follow Finsler geodesics.
Stochastic gravity: beyond semiclassical gravity
Energy Technology Data Exchange (ETDEWEB)
Verdaguer, E [Departament de Fisica Fonamental and CER en Astrofisica, Fisica de Particules i Cosmologia, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain)
2007-05-15
The back-reaction of a classical gravitational field interacting with quantum matter fields is described by the semiclassical Einstein equation, which has the expectation value of the quantum matter fields stress tensor as a source. The semiclassical theory may be obtained from the quantum field theory of gravity interacting with N matter fields in the large N limit. This theory breaks down when the fields quantum fluctuations are important. Stochastic gravity goes beyond the semiclassical limit and allows for a systematic and self-consistent description of the metric fluctuations induced by these quantum fluctuations. The correlation functions of the metric fluctuations obtained in stochastic gravity reproduce the correlation functions in the quantum theory to leading order in an 1/N expansion. Two main applications of stochastic gravity are discussed. The first, in cosmology, to obtain the spectrum of primordial metric perturbations induced by the inflaton fluctuations, even beyond the linear approximation. The second, in black hole physics, to study the fluctuations of the horizon of an evaporating black hole.
Puz, Michael J; Johnson, Barbara A; Murphy, Brendan J
2005-01-01
The application of a controlled-release asymmetric membrane (AM) coating containing cellulose acetate and polyethylene glycol 3350 (PEG3350) to a stable osmotic tablet core resulted in the oxidative degradation of active ingredient located in the core. It was hypothesized that the production of hydroperoxides from PEG3350 in the coating was responsible for the electrophilic oxidation of drug to the sulfoxide degradation product. The type and solubility of carboxylic acid excipient used to formulate the drug release profile of the osmotic tablet significantly influenced the amount of oxidation. By adding the antioxidant butylated hydroxytoluene (BHT) to the coating, oxidation was significantly inhibited in tablets placed on accelerated stability. Of three additives that were used to prevent oxidation [BHT, ferrous sulfate, and ethylenediaminetetraacetic acid (EDTA)], BHT was shown to be the most effective at preventing sulfoxide formation. The BHT was also shown to be more effective in the coating rather than in the core due to its location closer to the source of the oxidizing species, PEG3350, in the coating.
Leclercq, C; Arcella, D; Turrini, A
2000-12-01
The three recent EU directives which fixed maximum permitted levels (MPL) for food additives for all member states also include the general obligation to establish national systems for monitoring the intake of these substances in order to evaluate their use safety. In this work, we considered additives with primary antioxidant technological function for which an acceptable daily intake (ADI) was established by the Scientific Committee for Food (SCF): gallates, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and erythorbic acid. The potential intake of these additives in Italy was estimated by means of a hierarchical approach using, step by step, more refined methods. The likelihood of the current ADI to be exceeded was very low for erythorbic acid, BHA and gallates. On the other hand, the theoretical maximum daily intake (TMDI) of BHT was above the current ADI. The three food categories found to be main potential sources of BHT were "pastry, cake and biscuits", "chewing gums" and "vegetables oils and margarine"; they overall contributed 74% of the TMDI. Actual use of BHT in these food categories is discussed, together with other aspects such as losses of this substance in the technological process and percentage of ingestion in the case of chewing gums.
Naijian, Hamid Reza; Kohram, Hamid; Shahneh, Ahmad Zare; Sharafi, Mohsen; Bucak, Mustafa Numan
2013-04-01
Oxidative damage to sperm is one of the main causes for decline in motility and fertility of frozen-thawed sperm. Thus, it is crucial to use cryoprotectant agents in extender in order to prevent lethal intracellular ice crystal formation. The present study aims to evaluate the effects of different concentrations of the antioxidant butylated hyroxytoluene (BHT) on sperm parameters post-thaw. Semen was diluted into five equal aliquots of extender containing different concentrations of BHT (0, 0.5, 1, 2 and 4mM), aspirated into 0.25 mL straws, and equilibrated at 5°C for 2h. After equilibration, straws were frozen in liquid nitrogen vapor and plunged into liquid nitrogen for storage. Sperm parameters, including motility and progressive motility, viability, membrane integrity, acrosome integrity and capacitation status, were assessed. Malondialdehiyde (MDA) and glutathione peroxidase (GSH-PX) activity were also evaluated after freezing-thawing. Results of this experiment show that addition of 1mM of BHT to the extender for freezing of goat semen can improve motility, progressive motility and viability (PBHT (P>0.05). Therefore, we conclude that the optimum concentration of BHT for cryopreservation of goat semen is 1mM. Copyright © 2013 Elsevier Inc. All rights reserved.
Nifant'ev, I E; Shlyakhtin, A V; Bagrov, V V; Minyaev, M E; Churakov, A V; Karchevsky, S G; Birin, K P; Ivchenko, P V
2017-09-28
Numerous heteroleptic 2,6-di-tert-butyl-4-methylphenolate (BHT) magnesium complexes have been synthesized by treatment of (BHT)MgBu(THF)2 with various alcohols. Molecular structures of the complexes have been determined by X-ray diffraction. The magnesium coordination number in [(BHT)Mg(μ-OBn)(THF)]2 (3) and [(BHT)Mg(μ-O-tert-BuC6H4)(THF)]2 (4) is equal to 4. Complexes formed from esters of glycolic and lactic acids, [(BHT)Mg(μ-OCH2COOEt)(THF)]2 (5) and [(BHT)Mg(μ-OCH(CH3)COOCH2COO(t)Bu)(THF)]2 (6) contain chelate fragments with pentacoordinated magnesium. Compounds 3-6 contain THF molecules coordinated to magnesium atoms. Complex {(BHT)Mg[μ-O(CH2)3CON(CH3)2]}2 (7) does not demonstrate any tendency to form an adduct with THF. It has been experimentally determined that complexes 3 and 5 are highly active catalysts of lactide polymerization. The activity of 4 is rather low, and complex 7 demonstrates moderate productivity. According to DOSY NMR experiments, compounds 3 and 5 retain their dimeric structures even in THF. The free energies of model dimeric [(DBP)Mg(μ-OMe)(Sub)]2 and monomeric (DBP)Mg(OMe)(Sub)2 products on treatment of [(DBP)Mg(μ-OMe)(THF)]2 with a series of σ-electron donors (Sub) have been estimated by DFT calculations. These results demonstrate that the substitution of THF by Sub in a dimeric molecule is an energetically allowed process, whereas the dissociation of dimers is energetically unfavorable. DFT modeling of ε-CL and (dl)-lactide ROP catalyzed by dimeric and monomeric complexes showed that a cooperative effect of two magnesium atoms occurs within the ROP for binuclear catalytic species. A comparison of the reaction profiles for ROP catalyzed by binuclear and mononuclear species allowed us to conclude that the binuclear mechanism is favorable in early stages of ROP initiated by dimers 3 and 5.
On General Relativity with Massive Graviton
Berezhiani, Lasha
We begin this thesis by studying the properties of horizons in the de Rham-Gabadadze-Tolley model of massive GR. In massive gravity the generic black hole (BH) solutions on Minkowski space happen to convert horizons into a certain type of singularities. Here we explore whether these singularities can be avoided if space-time is not asymptotically Minkowskian. We find an exact analytic BH solution which evades the above problem by a transition at large scales to self-induced de Sitter (dS) space-time, with the curvature scale set by the graviton mass. The solution demonstrates that in massive GR, in the Schwarzschild coordinate system, a BH metric has to be accompanied by the Stückelberg fields with nontrivial backgrounds to prevent the horizons to convert into the singularities. We also find an analogous solution for a Reissner-Nordström BH on dS space. The second part concerns with the geometrical construction of massive gravity. Namely, the theory of gravity with an auxiliary extra dimension is known to give a ghost-free cubic completion of the Fierz-Pauli mass term in the decoupling limit. Yet, the theory propagates ghost in quartic order and beyond. Our work proposes a completion of the boundary condition in the auxiliary dimension that avoids ghosts order-by-order in the decoupling limit. Furthermore, we show that the multi-dimensional extension, with the rotationally invariant boundaries of the bulk, is equivalent to the model with a single auxiliary dimension. Therefore, all these constructions require the appropriate adjustment of the boundary condition. The other possible extension of the original model, by the Gauss-Bonnet term, is studied as well. In the last part we analyze the models known as "gravitational Higgs theories" against instabilities. We show that these models, although seemingly different from the effective field theories of massive gravity, are in fact equivalent to them. We also show the equivalence between the non-covariant mode
Non-trivial 2+1-Dimensional Gravity
Grigore, D R
2010-01-01
We analyze 2+1-dimensional gravity in the framework of quantum gauge theory. We find that Einstein gravity has a trivial physical subspace which reflects the fact that the classical solution in empty space is flat. Therefore we study massive gravity which is not trivial. In the limit of vanishing graviton mass we obtain a non-trivial massless theory different from Einstein gravity. We derive the interaction from descent equations and obtain the cosmological topologically massive gravity. However, in addition to Einstein and Chern-Simons coupling we need coupling to fermionic ghost and anti-ghost fields and to a vector-graviton field with the same mass as the graviton.
Dipolar dark matter with massive bigravity
Energy Technology Data Exchange (ETDEWEB)
Blanchet, Luc [GRECO Institut d’Astrophysique de Paris - UMR 7095 du CNRS,Université Pierre & Marie Curie,98" b" i" s boulevard Arago, 75014 Paris (France); Heisenberg, Lavinia [Nordita, KTH Royal Institute of Technology and Stockholm University,Roslagstullsbacken 23, 10691 Stockholm (Sweden); Department of Physics & The Oskar Klein Centre, AlbaNova University Centre,Roslagstullsbacken 21, 10691 Stockholm (Sweden)
2015-12-14
Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the dark matter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model.
Dipolar dark matter with massive bigravity
Blanchet, Luc; Heisenberg, Lavinia
2015-12-01
Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the dark matter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model.
Quantum gravity and Standard-Model-like fermions
Eichhorn, Astrid
2016-01-01
We discover that chiral symmetry does not act as an infrared attractor of the renormalization group flow under the impact of quantum gravity fluctuations. Thus, observationally viable quantum gravity models must respect chiral symmetry. In our truncation, asymptotically safe gravity does, as a chiral fixed point exists. A second non-chiral fixed point with massive fermions provides a template for models with dark matter. This fixed point disappears for more than 10 fermions, suggesting that an asymptotically safe ultraviolet completion for the standard model plus gravity enforces chiral symmetry.
Quantum gravity and Standard-Model-like fermions
Eichhorn, Astrid; Lippoldt, Stefan
2017-04-01
We discover that chiral symmetry does not act as an infrared attractor of the renormalization group flow under the impact of quantum gravity fluctuations. Thus, observationally viable quantum gravity models must respect chiral symmetry. In our truncation, asymptotically safe gravity does, as a chiral fixed point exists. A second non-chiral fixed point with massive fermions provides a template for models with dark matter. This fixed point disappears for more than 10 fermions, suggesting that an asymptotically safe ultraviolet completion for the standard model plus gravity enforces chiral symmetry.
Twisted spacetime in Einstein gravity
Zhang, Hongsheng
2016-01-01
We find a vacuum stationary twisted solution in four-dimensional Einstein gravity. Its frame dragging angular velocities are antisymmetric with respect to the equatorial plane. It possesses a symmetry of joint inversion of time and parity with respect to the equatorial plane. Its Arnowitt-Deser-Misner (ADM) mass and angular momentum are zero. It is curved but regular all over the manifold. Its Komar mass and Komar angular momentum are also zero. Its infinite red-shift surface coincides with its event horizon, since the event horizon does not rotate. Furthermore we extend this solution to the massive case, and find some similar properties. This solution is a stationary axisymmetric solution, but not Kerr. It explicitly proves that pure Einstein gravity permits different rotational mode other than Kerr. Our results demonstrate that the Einstein theory may have much more rich structures than what we ever imagine.
Logistics of massive transfusions.
DeLoughery, Thomas G
2010-01-01
Care of the patient with massive bleeding involves more than aggressive surgery and infusion of large amounts of blood products. The proper management of massive transfusions-whether they are in trauma patients or other bleeding patients-requires coordination of the personnel in the surgical suite or the emergency department, the blood bank, and laboratory.
Simplifying Massive Contour Maps
DEFF Research Database (Denmark)
Arge, Lars; Deleuran, Lasse Kosetski; Mølhave, Thomas;
2012-01-01
We present a simple, efficient and practical algorithm for constructing and subsequently simplifying contour maps from massive high-resolution DEMs, under some practically realistic assumptions on the DEM and contours.......We present a simple, efficient and practical algorithm for constructing and subsequently simplifying contour maps from massive high-resolution DEMs, under some practically realistic assumptions on the DEM and contours....
Rainich conditions in (2 + 1)-dimensional gravity
Krongos, D. S.; Torre, C. G.
2017-01-01
In (3 + 1) spacetime dimensions, the Rainich conditions are a set of equations expressed solely in terms of the metric tensor which are equivalent to the Einstein-Maxwell equations for non-null electromagnetic fields. Here we provide the analogous conditions for (2 + 1)-dimensional gravity coupled to electromagnetism. Both the non-null and null cases are treated. The construction of these conditions is based upon reducing the problem to that of gravity coupled to a scalar field, which we have treated elsewhere. These conditions can be easily extended to other theories of (2 + 1)-dimensional gravity. For example, we apply the geometrization conditions to topologically massive gravity coupled to the electromagnetic field and obtain a family of plane-fronted wave solutions.
Gravity localization in sine-Gordon braneworlds
Cruz, W T; Sousa, L J S; Almeida, C A S
2016-01-01
In this work we study two types of five-dimensional braneworld models given by sine-Gordon potentials. In both scenarios, the thick brane is generated by a real scalar field coupled to gravity. We focus our investigation on the localization of graviton field and the behaviour of the massive spectrum. In particular, we analyse the localization of massive modes by means of a relative probability method in a Quantum Mechanics context. Initially, considering a scalar field sine-Gordon potential, we find a resonance to the graviton at zero mode. However, when we consider a double sine-Gordon potential, the brane structure is changed allowing the existence of massless and massive resonant states. The new results show how the existence of an internal structure can aid in the emergence of massive resonant modes on the brane.
Gravity localization in sine-Gordon braneworlds
Energy Technology Data Exchange (ETDEWEB)
Cruz, W.T., E-mail: wilamicruz@gmail.com [Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE), Campus Juazeiro do Norte, 63040-540 Juazeiro do Norte, Ceará (Brazil); Maluf, R.V., E-mail: r.v.maluf@fisica.ufc.br [Departamento de Física, Universidade Federal do Ceará (UFC), C.P. 6030, 60455-760 Fortaleza, Ceará (Brazil); Sousa, L.J.S., E-mail: luisjose@fisica.ufc.br [Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE), Campus Canindé, 62700-000 Canindé, Ceará (Brazil); Almeida, C.A.S., E-mail: carlos@fisica.ufc.br [Departamento de Física, Universidade Federal do Ceará (UFC), C.P. 6030, 60455-760 Fortaleza, Ceará (Brazil)
2016-01-15
In this work we study two types of five-dimensional braneworld models given by sine-Gordon potentials. In both scenarios, the thick brane is generated by a real scalar field coupled to gravity. We focus our investigation on the localization of graviton field and the behaviour of the massive spectrum. In particular, we analyse the localization of massive modes by means of a relative probability method in a Quantum Mechanics context. Initially, considering a scalar field sine-Gordon potential, we find a localized state to the graviton at zero mode. However, when we consider a double sine-Gordon potential, the brane structure is changed allowing the existence of massive resonant states. The new results show how the existence of an internal structure can aid in the emergence of massive resonant modes on the brane.
Quantum corrections in massive bigravity and new effective composite metrics
Heisenberg, Lavinia
2015-05-01
We compute the one-loop quantum corrections to the interactions between the two metrics of the ghost-free massive bigravity. When considering gravitons running in the loops, we show how the structure of the interactions gets destabilized at the quantum level, exactly in the same way as in its massive gravity limit. A priori one might have expected a better quantum behavior, however, the broken diffeomorphism invariance out of the two initial diffeomorphisms in bigravity has similar consequences at the quantum level as the broken diffeomorphism in massive gravity. From lessons of the generated quantum corrections through matter loops we propose yet other types of effective composite metrics to which the matter fields can couple. Among these new effective metrics there might be one or more that could provide interesting phenomenology and important cosmological implications.
Quantum corrections in massive bigravity and new effective composite metrics
Heisenberg, Lavinia
2014-01-01
We compute the one-loop quantum corrections to the interactions between the two metrics of the ghost-free massive bigravity. When considering gravitons running in the loops, we show how the structure of the interactions gets destabilized at the quantum level, exactly in the same way as in its massive gravity limit. A priori one might have expected a better quantum behavior, however the broken diffeomorphism invariance out of the two initial diffeomorphisms in bigravity has similar consequences at the quantum level as the broken diffeomorphism in massive gravity. From lessons of the generated quantum corrections through matter loops we propose yet other types of effective composite metrics to which the matter fields can couple. Among these new effective metrics there might be one or more that could provide interesting phenomenology and important cosmological implications.
Interaction Between Massive and Massless Gravitons by Perturbing Topological Field Theory
Institute of Scientific and Technical Information of China (English)
E. Koorambas
2012-01-01
We test the Wu gauge theory of gravity with massive gravitons in the perturbing topological field theory framework. We show that the computation of the correlation function between massive and massless gravitons is reported up to 4-loop and appears to be unaffected by radiative correction. This result ensures the stability of the linking number between massive and massless gravitons with respect to the local perturbation, a result with potential wider applications in cosmology.
Planckian Interacting Massive Particles as Dark Matter
DEFF Research Database (Denmark)
Garny, Mathias; Sandora, McCullen; Sloth, Martin S.
2016-01-01
. In this case the WIMP miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian Interacting Massive Particle......, we show that the most natural mass larger than $0.01\\,\\textrm{M}_p$ is already ruled out by the absence of tensor modes in the CMB. This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the KK graviton mode...... as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark...
Institute of Scientific and Technical Information of China (English)
敬永计; 夏燕平; 姚勇; 龙德尚; 彭小燕
2011-01-01
Objective To explore the pretreatment technique for the detection of BHA and BHT from edible oils and fats by using gas chromatography. Methods Comparing the test results of two extraction and purification methods of nitrogen - purge and vacuum concentration by gas chromatography in the same test conditions of GC. The chromatographic conditions were suggested as follows: Gas chrom Q( 80 ～ 100mesh) covered by10％ QF - 1 ( m/m)in 2. 0 × 3 mm stainless steel column was used as stationary phase, injection temperature 200 ℃ , detector temperature 200 ℃ , column temperature 140 ℃ . Results The RSDs of two pretreatment technique were all lower than 5％ , the recovery rate was 88. 7％ - 96. 2％ and the detection limit were 0. 004 g/Kg. Conclusion It showed no statistical difference between two pretreatment methods of nitrogen - purge and vacuum concentration. The gas chromatography of nitrogen - purge is simple and accurate, and has a good reproducibility for the determination of BHA and BHT from vegetable oil.%目的 探讨气相色谱法检测食用油脂中BHA、BHT样品的前处理法.方法 在相同检测条件下比较柱层析后氮吹和减压浓缩2种样品前处理方法的结果.色谱条件为:色谱柱为长20 m内径3 mm不锈钢柱,内装涂有10%QF-1(m/m)的Gas chrom Q(80～100目)担体.气化室温度200℃,检测室温度200 ℃,柱温140℃.结果 2种前处理方法的相对标准差均小于5%,回收率在88.7%～96.2%之间,RSD为2.70%～3.78%,检出限为0.004 g/kg.结论 2种前处理方法测定结果差异无统计学意义,氮吹-气相色谱法简便、准确、重现性好,可用于植物油中BHA、BHT的测定.
National Oceanic and Atmospheric Administration, Department of Commerce — This data base (14,559 records) was received in January 1986. Principal gravity parameters include elevation and observed gravity. The observed gravity values are...
National Oceanic and Atmospheric Administration, Department of Commerce — The NGS Absolute Gravity data (78 stations) was received in July 1993. Principal gravity parameters include Gravity Value, Uncertainty, and Vertical Gradient. The...
Generalised matter couplings in massive bigravity
Energy Technology Data Exchange (ETDEWEB)
Melville, Scott [Harvard University,Cambridge, Massachusetts 02138 (United States); The Queen’s College,High Street, Oxford, OX1 4AW (United Kingdom); Noller, Johannes [The Queen’s College,High Street, Oxford, OX1 4AW (United Kingdom); Astrophysics, University of Oxford,DWB, Keble Road, Oxford, OX1 3RH (United Kingdom)
2016-01-18
We investigate matter couplings in massive bigravity. We find a new family of such consistent couplings, including and extending known consistent matter couplings, and we investigate their decoupling limits, ADM decompositions, Higuchi bounds and further aspects. We show that differences to previous known consistent couplings only arise beyond the Λ{sub 3} decoupling limit and discuss the uniqueness of consistent matter couplings and how this is related to the so-called symmetric vielbein condition. Since we work in a vielbein formulation, these results easily generalise to multi-gravity.
Testing gravity theories using tensor perturbations
Lin, Weikang; Ishak-Boushaki, Mustapha B.
2017-01-01
Primordial gravitational waves constitute a promising probe of the very early universe physics and the laws of gravity. We study the changes to tensor-mode perturbations that can arise in various modified gravity theories. These include a modified friction and a nonstandard dispersion relation. We introduce a physically motivated parametrization of these effects and use current data to obtain excluded parameter spaces. Taking into account the foreground subtraction, we then perform a forecast analysis focusing on the tensor-mode modified-gravity parameters as constrained by future experiments COrE, Stage-IV and PIXIE. For the tensor-to-scalar ratio r=0.01, we find the minimum detectible modified-gravity effects. In particular, the minimum detectable graviton mass is about 7.8˜9.7×10-33 eV, which is of the same order of magnitude as the graviton mass that allows massive gravity to produce late-time cosmic acceleration. Finally, we study the tensor-mode perturbations in modified gravity during inflation. We find that, the tensor spectral index would be additionally related to the friction parameter ν0 by nT=-3ν0-r/8. In some cases, the future experiments will be able to distinguish this relation from the standard one. In sum, primordial gravitational waves provide a complementary avenue to test gravity theories.
Meier, Brent W.; Gomez, Jose D.; Kirichenko, Oleg V.; Thompson, John A.
2008-01-01
An established model for mechanistic analysis of lung carcinogenesis involves administration of 3-methylcholanthrene to mice followed by several weekly injections of the tumor promoter 2,6-di-tert-butyl-4-methylphenol (BHT). BHT is metabolized to quinone methides (QMs) responsible for promoting tumor formation. QMs are strongly electrophilic and readily form adducts with proteins. The goal of the present study was to identify adducted proteins in the lungs of mice injected with BHT and to assess the potential impact of these modifications on tumorigenesis. Cytosolic proteins from treated mouse lungs were separated by two-dimensional electrophoresis, adducts detected by immunoblotting, and proteins identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Eight adducts were detected in the lungs of most, or all, of 6 experimental groups of BALB mice. Of these adducts, several were structural proteins but others, namely peroxiredoxin 6 (Prx6), Cu,Zn-superoxide dismutase (SOD1), carbonyl reductase, and selenium-binding protein 1, have direct or indirect antioxidant functions. When the 9000 g supernatant fraction of mouse lung was treated with BHT-QM (2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone), substantial lipid peroxidation and increases in hydrogen peroxide and superoxide formation were observed. Studies with human Prx6 and bovine SOD1 demonstrated inhibition of enzyme activity concomitant with adduct formation. LC-MS/MS analysis of digests of adducted Prx6 demonstrated adduction of both Cys 91 and Cys 47; the latter residue is essential for peroxidatic activity. Analysis of QM-treated bovine SOD1 by matrix-assisted laser desorption ionization-time of flight MS demonstrated predominance of a mono-adduct at His 78. This study provides evidence that indicates Prx6, SOD1 and possibly other antioxidant enzymes in mouse lung are inhibited by BHT-derived QMs leading to enhanced levels of reactive oxygen species and inflammation, and providing a
Induced Gravity I: Real Scalar Field
Einhorn, Martin B
2016-01-01
We show that classically scale invariant gravity coupled to a single scalar field can undergo dimensional transmutation and generate an effective Einstein-Hilbert action for gravity, coupled to a massive dilaton. The same theory has an ultraviolet fixed point for coupling constant ratios such that all couplings are asymptotically free. However the catchment basin of this fixed point does not include regions of coupling constant parameter space compatible with locally stable dimensional transmutation. We believe that the desirable outcome may obtain in more complicated theories with non-Abelian gauge interactions.
Induced gravity I: real scalar field
Energy Technology Data Exchange (ETDEWEB)
Einhorn, Martin B. [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); Jones, D.R. Timothy [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA 93106-4030 (United States); Department of Mathematical Sciences,University of Liverpool, Liverpool L69 3BX (United Kingdom)
2016-01-05
We show that classically scale invariant gravity coupled to a single scalar field can undergo dimensional transmutation and generate an effective Einstein-Hilbert action for gravity, coupled to a massive dilaton. The same theory has an ultraviolet fixed point for coupling constant ratios such that all couplings are asymptotically free. However the catchment basin of this fixed point does not include regions of coupling constant parameter space compatible with locally stable dimensional transmutation. In a companion paper, we will explore whether this more desirable outcome does obtain in more complicated theories with non-Abelian gauge interactions.
Gravity with background fields and diffeomorphism breaking
Bluhm, Robert
2016-01-01
Effective gravitational field theories with background fields break local Lorentz symmetry and diffeomorphism invariance. Examples include Chern-Simons gravity, massive gravity, and the Standard-Model Extension (SME). The physical properties and behavior of these theories depend greatly on whether the spacetime symmetry breaking is explicit or spontaneous. With explicit breaking, the background fields are fixed and nondynamical, and the resulting theories are fundamentally different from Einstein's General Relativity (GR). However, when the symmetry breaking is spontaneous, the background fields are dynamical in origin, and many of the usual features of Einstein's GR still apply.
Probing modified gravity via the mass-temperature relation of galaxy clusters
Hammami, Amir
2016-01-01
We propose that the mass-temperature relation of galaxy clusters is a prime candidate for testing gravity theories beyond Einstein's general relativity. Using cosmological simulations, we find that in modified gravity the mass-temperature relation varies significantly from the standard gravity prediction $M \\propto T^{1.73}$. To be specific, for symmetron models with a coupling factor of $\\beta = 1$ we find a lower limit to the power law as $M \\propto T^{1.6}$; and for f(R) gravity we compute predictions based on the model parameters. We show that the mass-temperature relation, for screened modified gravities, is significantly different from that of standard gravity for the less massive and colder galaxy clusters, while being indistinguishable from Einstein's gravity at massive, hot galaxy clusters.
Peculiarities of massive vectormesons
Schroer, Bert
2015-01-01
Massive QED, different from its massless counterpart, posesses two conserved charges; one is a screened (vanishing) Maxwell charge which is directly associated with the massive vectormesons through the identically conserved Maxwell current while the particle-antiparticle counting charge has its origin on the matter side. A somewhat peculiar situation arises in case of A-H couplings to Hermitian matter fields; in that case the only current is the screened Maxwell current and the coupling disappears in the massless limit. In case of selfinteracting massive vectormesons the situation becomes even more peculiar in that the usually renormalizability guaranteeing validity of the first order power-counting criterion breaks down in second order and requires the compensatory presence of an additional A-H coupling. In this case the massive counterpart of (spinor or scalar) QCD needs the presence of the A-H coupling which only disappears in the massless limit. Some aspect of these observation have already been noticed i...
Nash, Patrick Lee
2010-01-01
A theory of a new gravitational interaction is described. This theory follows naturally from a new Lagrangian formulation of Maxwell's theory for photons and electrons (and positrons) whose associated Euler Lagrange equations imply the conventional Maxwell equations, but which possesses new \\textbf{\\emph{bosonic}} spinor degrees of freedom that may be associated with a new type of fundamental gravitational interaction. The precise character of this gravitational interaction with a photon vector potential is explicitly defined in terms of a local U(1)-invariant Lagrangian in Eq.[\\ref{Lagrangian3}]. However in Section \\ref{ssec:Simple-Cosmolo-Model}, in order to parallel the well known Friedmann model in cosmology, a phenomenological description of the new gravitational interaction coupled to Newton-Einstein gravity that is sourced by an ideal fluid is discussed. % % To lay the foundation for a description of the new gravitational interaction our new formulation of Maxwell's theory must first be described. It i...
Magueijo, J; Magueijo, Joao; Smolin, Lee
2004-01-01
Non-linear special relativity (or doubly special relativity) is a simple framework for encoding properties of flat quantum space-time. In this paper we show how this formalism may be generalized to incorporate curvature (leading to what might be called ``doubly general relativity''). We first propose a dual to non-linear realizations of relativity in momentum space, and show that for such a dual the space-time invariant is an energy-dependent metric. This leads to an energy-dependent connection and curvature, and a simple modification to Einstein's equations. We then examine solutions to these equations. We find the counterpart to the cosmological metric, and show how cosmologies based upon our theory of gravity may solve the ``horizon problem''. We discuss the Schwarzchild solution, examining the conditions for which the horizon is energy dependent. We finally find the weak field limit.
Lombard, John
2016-01-01
We introduce the construction of a new framework for probing discrete emergent geometry and boundary-boundary observables based on a fundamentally a-dimensional underlying network structure. Using a gravitationally motivated action with Forman weighted combinatorial curvatures and simplicial volumes relying on a decomposition of an abstract simplicial complex into realized embeddings of proper skeletons, we demonstrate properties such as a minimal volume-scale cutoff, the necessity of a positive-definite cosmological constant as a regulator for non-degenerate geometries, and naturally emergent simplicial structures from Metropolis network evolution simulations with no restrictions on attachment rules or regular building blocks. We see emergent properties which echo results from both the spinfoam formalism and causal dynamical triangulations in quantum gravity, and provide analytical and numerical results to support the analogy. We conclude with a summary of open questions and intent for future work in develop...
Newtonian gravity in loop quantum gravity
Smolin, Lee
2010-01-01
We apply a recent argument of Verlinde to loop quantum gravity, to conclude that Newton's law of gravity emerges in an appropriate limit and setting. This is possible because the relationship between area and entropy is realized in loop quantum gravity when boundaries are imposed on a quantum spacetime.
Newtonian gravity in loop quantum gravity
Smolin, Lee
2010-01-01
We apply a recent argument of Verlinde to loop quantum gravity, to conclude that Newton's law of gravity emerges in an appropriate limit and setting. This is possible because the relationship between area and entropy is realized in loop quantum gravity when boundaries are imposed on a quantum spacetime.
Massive to gauge field reduction and gravitational wave zone information
Deser, S
2016-01-01
We show explicitly that massive, Abelian, vector, just like (properly defined) massive tensor, fields limit smoothly to their massless, gauge, versions: they emit only maximal helicity radiation and mediate Coulomb and (special relativistic) Newtonian, forces between their (conserved) sources. Our main motivation, though, is to show that the recent gravitational wave detection probably cannot directly rule out very long-range gravity: Even though the waves were emitted in a strong field regime, their being detected in the weak field wave zone means the above equivalences apply. There remains the, not unlikely, possibility that no strong field generation of radiation in massive models can reproduce the observed ring-down patterns. Separately, the smooth linear limiting behaviors show that the discontinuity lies not in the mass alone, but rather in Abelian versus non-Abelian, Yang-Mills and General Relativity, regimes, whose respective massive versions are known to be non-physical.
Murakami, Yukio; Kawata, Akifumi; Katayama, Tadashi; Fujisawa, Seiichiro
2015-01-01
The artificial complex phenols, 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP) exert efficient antioxidant activity; however, they are considerable toxic and potentially tumor-promoting. These phenols, particularly in combinations, have enhanced antioxidant activity due to synergistic interactions and produce bioactive intermediates such as quinone methide. We investigated the anti-inflammatory activity of BHA, BHT and TBP, and combinations of BHT/BHA (in molar ratios of 1:1, 1:2, 1:3 and 2:1), BHT/TBP (1:1), and BHA/TBP (1:1), using gene-expression systems for cyclooxygenase-2 (Cox2) and tumor necrosis facto-alpha (Tnfa) in RAW264.7 cells. The inhibitory effects of BHA, BHT and TBP on expression of Cox2 and Tnfa genes upon stimulation with Escherichia coli lipopolysaccharide (LPS) or Porphyomonas gingivalis (Pg) fimbriae were determined using real-time polymerase chain reaction. The inhibitory effect on expression of Cox2 and Tnfa genes upon stimulation with LPS and fimbriae was greatly enhanced by the combination of two antioxidants (molar ratio 1:1), BHT/BHA. In addition, that of the Cox2 gene, but not of Tnfa gene was slightly enhanced by a combination of equimolar BHT/TBP and BHA/TBP. None of the antioxidants alone exerted any anti-inflammatory activity upon stimulation with LPS, but a slight anti-inflammatory activity was observed upon stimulation with Pg fimbriae. The inhibitory effect of the BHT/BHA combination on expression of Cox2 mRNA upon stimulation with LPS was investigated at afferent molar ratios, and a molar ratio of 1:1 was found to have considerably less effect than a molar ratio of 1:2 or 2:1. The 1:3 combination had no effect. The combination of BHT and BHA at a molar ratio of 0.5-2 exerts potent anti-inflammatory activity. This anti-inflammatory activity on the generation of inflammatory mediators in LPS-activated RAW264.7 cells may be attributable to complex synergistic
Kaluza-Klein reduction of massive and partially massless spin-2 fields
Bonifacio, James; Hinterbichler, Kurt
2017-01-01
We describe the dimensional reduction of massive and partially massless spin-2 fields on general Einstein direct product manifolds. As with massless fields, the higher-dimensional gauge symmetry of the partially massless field displays itself upon dimensional reduction as a tower of Stückelberg symmetries for the massive modes of the tower. Unlike the massless case, the zero mode of the gauge symmetry does not display itself as a lower-dimensional non-Stückelberg gauge symmetry enforcing partial masslessness on the zero mode. Partial masslessness is destroyed by the dimensional reduction and the zero-mode gauge symmetry instead serves to eliminate the radion. In addition, we study the fully nonlinear dimensional reduction of de Rham-Gabadadze-Tolley massive gravity on a circle, which results in a massive scalar-tensor-vector theory which we expect to be ghost free, and whose scalar-tensor sector is a special case of mass-varying massive gravity.
Kaluza-Klein Reduction of Massive and Partially Massless Spin-2
Bonifacio, James
2016-01-01
We describe the dimensional reduction of massive and partially massless spin-2 fields on general Einstein direct product manifolds. As with massless fields, the higher-dimensional gauge symmetry of the partially massless field displays itself upon dimensional reduction as a tower of St\\"uckelberg symmetries for the massive modes of the tower. Unlike the massless case, the zero mode of the gauge symmetry does not display itself as a lower-dimensional non-Stuckelberg gauge symmetry enforcing partial masslessness on the zero mode. Partial masslessness is destroyed by the dimensional reduction and the zero mode gauge symmetry instead serves to eliminate the radion. In addition, we study the fully non-linear dimensional reduction of dRGT massive gravity on a circle, which results in a massive scalar-tensor-vector theory which we expect to be ghost-free, and whose scalar-tensor sector is a special case of mass-varying massive gravity.
Lineal gravity from planar gravity
Achúcarro, A
1993-01-01
We show how to obtain the two-dimensional black hole action by dimensional reduction of the three-dimensional Einstein action with a non-zero cosmological constant. Starting from the Chern-Simons formulation of 2+1 gravity, we obtain the 1+1 dimensional gauge formulation given by Verlinde. Remarkably, the proposed reduction shares the relevant features of the formulation of Cangemi and Jackiw, without the need for a central charge in the algebra. We show how the Lagrange multipliersin these formulations appear naturally as the remnants of the three dimensional connection associated to symmetries that have been lostin the dimensional reduction. The proposed dimensional reduction involves a shift in the three dimensional connection whose effect is to make the length of the extra dimension infinite.
Fedoreyeva, L I; Aleksandrushkina, N I; Dunaevsky, Ya E; Belozersky, M A; Vanyushin, B F
2003-04-01
It was established that total proteolytic activity in etiolated wheat seedlings changes in ontogenesis in cycles: peaks of proteolytic activity correspond to the 3rd, 5th, and 8th days of seedling growth, respectively. The maximum of proteolytic activity preceded the maximum of nuclease activity, which may be due to activation of nucleases by proteolytic enzymes. According to inhibitory analysis the cysteine and serine proteases play the main role in apoptosis in wheat coleoptiles. Growing of seedlings in the presence of ethrel stimulated apoptosis in the coleoptile, and it increased (almost 6-fold) the proteolytic activity in its cells. On the other hand, the antioxidant ionol (BHT) suppressed the induction of proteases, particularly at the second stage of coleoptile development, and it slowed down the increase in the nuclease activity after 6th day of the seedling life. It is suggested that phytohormones and antioxidants participate in regulation of apoptosis in the ageing coleoptile, directly or indirectly effecting the proteolytic apparatus in the coleoptile cells.
Semi-classical central charge in topologically massive gravity
Compère, Geoffrey
2008-01-01
It is shown that the warped black holes geometries obtained recently in 0807.3040 admit an algebra of asymptotic symmetries isomorphic to the semi-direct product of a Virasoro algebra and an algebra of currents. The realization of this asymptotic symmetry by canonical charges allows one to find the central charge of the Virasoro algebra. The negative value $c = -\\frac{(5\\hat{\
On scale-free extensions of massive (bi-)gravity
Cusin, Giulia; Noller, Johannes
2016-01-01
We discuss a scale-free model of bigravity, in which the mass parameter of the standard bigravity potential is promoted to a dynamical scalar field. This modification retains the ghost-free bigravity structure, in particular it remains free of the Boulware-Deser ghost. We investigate the theory's interaction structure, focusing on its consistent scaling limits and strong coupling scales. Furthermore we explore the model's quadratic action, both around generic background configurations and paying special attention to cosmological backgrounds and to the associated background evolution. Finally we consider the possibility of realizing a phase of late-time acceleration as well as a quasi-de Sitter inflationary stage at early times, when the promoted "mass scalar" becomes the inflaton.
On scale-free extensions of massive (bi-)gravity
Cusin, Giulia; Khosravi, Nima; Noller, Johannes
2017-02-01
We discuss a scale-free model of bigravity, in which the mass parameter of the standard bigravity potential is promoted to a dynamical scalar field. This modification retains the ghost-free bigravity structure, in particular it remains free of the Boulware-Deser ghost. We investigate the theory's interaction structure, focusing on its consistent scaling limits and strong coupling scales. Furthermore we explore the model's quadratic action, both around generic background configurations and paying special attention to cosmological backgrounds and to the associated background evolution. Finally we consider the possibility of realising a phase of late-time acceleration as well as a quasi-de Sitter inflationary stage at early times, when the promoted "mass scalar" becomes the inflaton.
Propagating Degrees of Freedom in f(R Gravity
Directory of Open Access Journals (Sweden)
Yun Soo Myung
2016-01-01
Full Text Available We have computed the number of polarization modes of gravitational waves propagating in the Minkowski background in f(R gravity. These are three of two from transverse-traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. There is no massless breathing mode and the massive trace mode corresponds to the Ricci scalar. A newly defined metric tensor in f(R gravity satisfies the transverse-traceless (TT condition as well as the TT wave equation.
Freitas, Kellen Heloizy Garcia; Fatibello-Filho, Orlando
2010-05-15
A simple electrochemical method was developed for the single and simultaneous determination of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in food samples using square-wave voltammetry (SWV). A carbon composite electrode modified (MCCE) with copper (II) phosphate immobilized in a polyester resin was proposed. The modified electrode allowed the detection of BHA and BHT at potentials lower than those observed at unmodified electrodes. A separation of about 430mV between the peak oxidation potentials of BHA and BHT in binary mixtures was obtained. The calibration curves for the simultaneous determination of BHA and BHT demonstrated an excellent linear response in the range from 3.4x10(-7) to 4.1x10(-5)molL(-1) for both compounds. The detection limits for the simultaneous determination of BHA and BHT were 7.2x10(-8) and 9.3x10(-8)molL(-1), respectively. In addition, the stability and repeatability of the electrode were determined. The proposed method was successfully applied in the simultaneous determination of BHA and BHT in several food samples, and the results obtained were found to be similar to those obtained using the high performance liquid chromatography method with agreement at 95% confidence level.
Bauer, A K; Dwyer-Nield, L D; Hankin, J A; Murphy, R C; Malkinson, A M
2001-12-01
An inflammatory response accompanies the reversible pneumotoxicity caused by butylated hydroxytoluene (BHT) administration to mice. Lung tumor formation is promoted by BHT administration following an initiating agent in BALB/cByJ mice, but not in CXB4 mice. To assess the contribution of inflammation to this differential susceptibility, we quantitatively characterized inflammation after one 150 mg/kg body weight, followed by three weekly 200 mg/kg ip injections of BHT into male mice of both strains. This examination included inflammatory cell infiltrate and protein contents in bronchoalveolar lavage (BAL) fluid, cyclooxygenase (COX)-1 and COX-2 expression in lung extracts, and PGE(2) and PGI(2) production by isolated bronchiolar Clara cells. BAL macrophage and lymphocyte numbers increased in BALB mice (PBHT in CXB4 mice. BALB mice fed aspirin (400 mg/kg of chow) for two weeks prior to BHT treatment had reduced inflammatory cell infiltration. Our results support a hypothesis that resistance to BHT-induced inflammation in CXB4 mice accounts, at least in part, for the lack of effect of BHT on lung tumor multiplicity in this strain.
Planckian Interacting Massive Particles as Dark Matter
Garny, Mathias; Sandora, McCullen; Sloth, Martin S.
2016-03-01
The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01 Mp is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter.
Planckian Interacting Massive Particles as Dark Matter.
Garny, Mathias; Sandora, McCullen; Sloth, Martin S
2016-03-11
The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01M_{p} is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter.
Nam, Soonkeon
2016-01-01
We apply the Wald formalism to obtain masses and angular momenta of black holes in three dimensional gravity theories using first order formalism. Wald formalism suggests mass and angular momentum of black hole as an integration of some charge variation form at its boundary. The action of the three dimensional gravity theories can be represented by the form including some auxiliary fields. As well-known examples we have calculated mass and angular momentum of some black holes in topologically massive gravity and new massive gravity theories using first order formalism. We have also calculated mass and angular momentum of BTZ black hole and new type black hole in minimal massive gravity theory with the action represented by first order formalism.
Propagating degrees of freedom in f(R) gravity
Myung, Yun Soo
2016-01-01
We have computed the number of polarization modes of gravitational waves propagating in the Minkowski background in f(R) gravity. This is three of two from transverse-traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. There is no massless breathing mode and the massive trace mode corresponds to the Ricci scalar. A newly defined metric tensor satisfies the transverse-traceless (TT) condition as well as the TT wave equation.
Linker, Patrick
2016-01-01
A couple of quantum gravity theories were proposed to make theoretical predictions about the behavior of gravity. The most recent approach to quantum gravity, called E-theory, is proposed mathematical, but there is not formulated much about what dynamics of gravity this theory proposes. This research paper treats the main results of the application of E-theory to General relativity involving conservation laws and scattering of particles in presence of gravity. Also the low-energy limit of thi...
Lee, Jun Hyun; Jung, Mun Yhung
2010-08-01
Singlet oxygen quenching by synthetic antioxidants (BHA, BHT, and TBHQ) was directly observed by spectroscopic monitoring of luminescence at 1268 nm. The luminescence data showed unambiguous evidence of singlet oxygen quenching by synthetic phenolic antioxidants with the highest activity for TBHQ, followed by BHA and BHT. The protective activities of these synthetic antioxidants on alpha-terpinene oxidation with chemically-induced singlet oxygen under dark further confirmed their singlet oxygen quenching abilities. Total singlet oxygen quenching rate constants (k(r) + k(q)) of BHA, BHT, and TBHQ were determined in a system containing alpha-terpinene (as a singlet oxygen trap) and methylene blue (as a sensitizer) during light irradiation, and the values were 5.14 x 10(7), 3.41 x 10(6), and 1.99 x 10(8) M(-1)s(-1), respectively. After the k(r) value of alpha-terpinene was first determined, the k(r) values of the synthetic antioxidants were calculated by measuring their relative reaction rates with singlet oxygen to that of alpha-terpinene under the identical conditions. The k(r) values of the BHA, BHT, and TBHQ were 3.90 x 10(5), 1.23 x 10(5), and 2.93 x 10(6), M(-1)s(-1). The percent partition of chemical quenching over total singlet oxygen quenching (k(r) x 100)/(k(r) + k(q)) for BHA, BHT, and TBHQ were 0.76%, 3.61%, and 1.47%, respectively. The results showed that the synthetic antioxidants quench singlet oxygen almost exclusively through the mechanism of physical quenching. This represents the first report on the singlet oxygen quenching mechanism of these synthetic antioxidants. Practical Application: The synthetic antioxidants, especially TBHQ, have been found to have a strong singlet oxygen quenching ability. This article also clearly showed that singlet oxygen quenching by synthetic antioxidants was mainly by the physical quenching mechanism. The results suggested that these synthetic antioxidants, especially TBHQ, could be used practically for the protection
Cosmic decoherence: massive fields
Energy Technology Data Exchange (ETDEWEB)
Liu, Junyu [Department of Physics, California Institute of Technology,Pasadena, California 91125 (United States); School of the Gifted Young, University of Science and Technology of China,Hefei, Anhui 230026 (China); Sou, Chon-Man; Wang, Yi [Department of Physics, The Hong Kong University of Science and Technology,Clear Water Bay, Kowloon, Hong Kong (China)
2016-10-14
We study the decoherence of massive fields during inflation based on the Zurek’s density matrix approach. With the cubic interaction between inflaton and massive fields, the reduced density matrix for the massive fields can be calculated in the Schrödinger picture which is related to the variance of the non-Gaussian exponent in the wave functional. The decoherence rate is computed in the one-loop form from functional integration. For heavy fields with m≳O(H), quantum fluctuations will easily stay in the quantum state and decoherence is unlikely. While for light fields with mass smaller than O(H), quantum fluctuations are easily decohered within 5∼10 e-folds after Hubble crossing. Thus heavy fields can play a key role in studying problems involving inflationary quantum information.
Cosmic Decoherence: Massive Fields
Liu, Junyu; Wang, Yi
2016-01-01
We study the decoherence of massive fields during inflation based on the Zurek's density matrix approach. With the cubic interaction between inflaton and massive fields, the reduced density matrix for the massive fields can be calculated in the Schr\\"odinger picture which is related to the variance of the non-Gaussian exponent in the wave functional. The decoherence rate is computed in the one-loop form from functional integration. For heavy fields with $m\\gtrsim \\mathcal{O}(H)$, quantum fluctuations will easily stay in the quantum state and decoherence is unlikely. While for light fields with mass smaller than $\\mathcal{O}(H)$, quantum fluctuations are easily decohered within $5\\sim10$ e-folds after Hubble crossing. Thus heavy fields can play a key role in studying problems involving inflationary quantum information.
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.
Fasimpaur, Karen
2013-01-01
MOOCs--massive open online courses--are all the rage these days, with hundreds of thousands of participants signing up and investors plunking down millions to get a piece of the pie. Why is there so much excitement about this new disruptive form of online learning, and how does this model apply to professional learning for teachers? Traditional…
Preibisch, T; Zinnecker, H; Preibisch, Thomas; Weigelt, Gerd; Zinnecker, Hans
2000-01-01
We discuss the observed multiplicity of massive stars and implications on theories of massive star formation. After a short summary of the literature on massive star multiplicity, we focus on the O- and B-type stars in the Orion Nebula Cluster, which constitute a homogenous sample of very young massive stars. 13 of these stars have recently been the targets of a bispectrum speckle interferometry survey for companions. Considering the visual and also the known spectroscopic companions of these stars, the total number of companions is at least 14. Extrapolation with correction for the unresolved systems suggests that there are at least 1.5 and perhaps as much as 4 companions per primary star on average. This number is clearly higher than the mean number of about 0.5 companions per primary star found for the low-mass stars in the general field population and also in the Orion Nebula cluster. This suggests that a different mechanism is at work in the formation of high-mass multiple systems in the dense Orion Nebu...
Massive antenatal fetomaternal hemorrhage
DEFF Research Database (Denmark)
Dziegiel, Morten Hanefeld; Koldkjaer, Ole; Berkowicz, Adela
2005-01-01
Massive fetomaternal hemorrhage (FMH) can lead to life-threatening anemia. Quantification based on flow cytometry with anti-hemoglobin F (HbF) is applicable in all cases but underestimation of large fetal bleeds has been reported. A large FMH from an ABO-compatible fetus allows an estimation...
Neutralino annihilation into massive quarks with supersymmetric QCD corrections
Herrmann, Björn; Klasen, Michael; Kovařík, Karol
2009-03-01
We compute the full O(αs) supersymmetric (SUSY)-QCD corrections for neutralino annihilation into massive quarks through gauge or Higgs bosons and squarks in the minimal supersymmetric standard model, including the known resummation of logarithmically enhanced terms. The numerical impact of the corrections on the extraction of SUSY mass parameters from cosmological data is analyzed for gravity-mediated SUSY-breaking scenarios and shown to be sizable, so that these corrections must be included in common analysis tools.
Neutralino Annihilation into Massive Quarks with SUSY-QCD Corrections
Herrmann, Björn; Kovarik, Karol
2009-01-01
We compute the full O(alpha_s) supersymmetric (SUSY) QCD corrections for neutralino annihilation into massive quarks through gauge or Higgs bosons and squarks in the Minimal Supersymmetric Standard Model (MSSM), including the known resummation of logarithmically enhanced terms. The numerical impact of the corrections on the extraction of SUSY mass parameters from cosmological data is analyzed for gravity-mediated SUSY breaking scenarios and shown to be sizable, so that these corrections must be included in common analysis tools.
UV, optical and near-IR diagnostics of massive stars
Martins, F
2010-01-01
We present an overview of a few spectroscopic diagnostics of massive stars. We explore the following wavelength ranges: UV (1000 to 2000 A), optical (4000--7000 A) and near-infrared (mainly H and K bands). The diagnostics we highlight are available in O and Wolf-Rayet stars as well as in B supergiants. We focus on the following parameters: effective temperature, gravity, surface abundances, luminosity, mass loss rate, terminal velocity, wind clumping, rotation/macroturbulence and surface magnetic field.
Interactive Lagrangian density between massive photons and gravitons
Institute of Scientific and Technical Information of China (English)
DENG Yan-bin
2006-01-01
The interactive Lagrangian density of massive photons and gravitons is proposed after an investigation into the interaction between photons with or without mass under the influence of gravity either as classical field, gravitational wave, or gravitons from a perspective of quantum field. This interactive Lagrangian density can provide a step-stone for further research of gravitational wave and the possible rest mass of photon.
... medlineplus.gov/ency/article/003587.htm Urine specific gravity test To use the sharing features on this page, please enable JavaScript. Urine specific gravity is a laboratory test that shows the concentration ...
National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (24,284 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity...
Northern Oklahoma Gravity Data
National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (710 records) were compiled by Professor Ahern. This data base was received in June 1992. Principal gravity parameters include latitude,...
National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...
National Oceanic and Atmospheric Administration, Department of Commerce — The Decade of North American Geology (DNAG) gravity grid values, spaced at 6 km, were used to produce the Gravity Anomaly Map of North America (1987; scale...
Cadiz, California Gravity Data
National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (32 records) were gathered by Mr. Seth I. Gutman for AridTech Inc., Denver, Colorado using a Worden Prospector gravity meter. This data base...
Classical Weyl Transverse Gravity
Oda, Ichiro
2016-01-01
We study various classical aspects of the Weyl transverse (WTDiff) gravity in a general space-time dimension. First of all, we clarify a classical equivalence among three kinds of gravitational theories, those are, the conformally-invariant scalar tensor gravity, Einstein's general relativity and the WTDiff gravity via the gauge fixing procedure. Secondly, we show that in the WTDiff gravity the cosmological constant is a mere integration constant as in unimodular gravity, but it does not receive any radiative corrections unlike the unimodular gravity. A key point in this proof is to construct a covariantly conserved energy-momentum tensor, which is achieved on the basis of this equivalence relation. Thirdly, we demonstrate that the Noether current for the Weyl transformation is identically vanishing, thereby implying that the Weyl symmetry existing in both the conformally-invariant scalar tensor gravity and the WTDiff gravity is a "fake" symmetry. We find it possible to extend this proof to all matter fields,...
Bimetric gravity and dark matter
Bernard, Laura; Heisenberg, Lavinia
2015-01-01
We review some recent proposals for relativistic models of dark matter in the context of bimetric gravity. The aim is to solve the problems of cold dark matter (CDM) at galactic scales, and to reproduce the phenomenology of the modified Newtonian dynamics (MOND), while still being in agreement with the standard cosmological model $\\Lambda$-CDM at large scales. In this context a promising alternative is dipolar dark matter (DDM) in which two different species of dark matter particles are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. The phenomenology of MOND then results from a mechanism of gravitational polarization. Probably the best formulation of the model is within the framework of recently developed massive bigravity theories. Then the gravitational sector of the model is safe by construction, but a ghostly degree of freedom in the decoupling limit is still present in the dark matter sector. Future work should analyse the cosmological solutions of...
Gravitomagnetic effects in conformal gravity
Said, Jackson Levi; Adami, Kristian Zarb
2014-01-01
Gravitomagnetic effects are characterized by two phenomena: first, the geodetic effect which describes the precession of the spin of a gyroscope in a free orbit around a massive object, second, the Lense-Thirring effect which describes the precession of the orbital plane about a rotating source mass. We calculate both these effects in the fourth-order theory of conformal Weyl gravity for the test case of circular orbits. We show that for the geodetic effect a linear term arises which may be interesting for high radial orbits, whereas for the Lense-Thirring effect the additional term has a diminishing effect for most orbits. Circular orbits are also considered in general leading up to a generalization of Kepler's third law.
Perturbations of Dark Matter Gravity
Maia, M D; Müller, D; 10.1142/S0218271809015072
2009-01-01
Until recently the study of the gravitational field of dark matter was primarily concerned with its local effects on the motion of stars in galaxies and galaxy clusters. On the other hand, the WMAP experiment has shown that the gravitational field produced by dark matter amplifies the higher acoustic modes of the CMBR power spectrum, more intensely than the gravitational field of baryons. Such a wide range of experimental evidences from cosmology to local gravity suggests the necessity of a comprehensive analysis of the dark matter gravitational field per se, regardless of any other attributes that dark matter may eventually possess. In this paper we introduce and apply Nash's theory of perturbative geometry to the study of the dark matter gravitational field alone, in a higher-dimensional framework. It is shown that the dark matter gravitational perturbations in the early universe can be explained by the extrinsic curvature of the standard cosmology. Together with the estimated presence of massive neutrinos,...
Bukley, Angie; Paloski, William; Clement, Gilles
2006-01-01
This chapter discusses potential technologies for achieving artificial gravity in a space vehicle. We begin with a series of definitions and a general description of the rotational dynamics behind the forces ultimately exerted on the human body during centrifugation, such as gravity level, gravity gradient, and Coriolis force. Human factors considerations and comfort limits associated with a rotating environment are then discussed. Finally, engineering options for designing space vehicles with artificial gravity are presented.
Terrestrial Gravity Fluctuations
Harms, Jan
2015-12-01
Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10-23 Hz-1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of
Terrestrial Gravity Fluctuations.
Harms, Jan
2015-01-01
Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10(-23) Hz(-1/2) above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of
Terrestrial Gravity Fluctuations
Directory of Open Access Journals (Sweden)
Jan Harms
2015-12-01
Full Text Available Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10^–23 Hz^–1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our
Terrestrial Gravity Fluctuations
Harms, Jan
2015-01-01
The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of terrestrial gravity fluctuations will have great impact on the future development of GW detectors and high-precision gravimetry in general, and many open questions need to be answered still as emphasized in this article.
Kupfer, Rene; Dwyer-Nield, Lori D; Malkinson, Alvin M; Thompson, John A
2002-08-01
Acute pulmonary toxicity and tumor promotion by the food additive 2,6-di-tert-butyl-4-methylphenol (BHT) in mice are well documented. These effects have been attributed to either of two quinone methides, 2,6-di-tert-butyl-4-methylenecyclohexa-2,5-dienone (BHT-QM) formed through direct oxidation of BHT by pulmonary cytochrome P450 or a quinone methide formed by hydroxylation of a tert-butyl group of BHT (to form BHTOH) followed by oxidation of this metabolite to BHTOH-QM. BHTOH-QM is a more reactive electrophile compared to BHT-QM due to intramolecular interactions of the side-chain hydroxyl with the carbonyl oxygen. To further examine this bioactivation pathway, an analogue of BHTOH was prepared, 2-tert-butyl-6-(1'-hydroxy-1'-methyl)ethyl-4-methylphenol (BPPOH), that is structurally very similar to BHTOH but forms a quinone methide (BPPOH-QM) capable of more efficient intramolecular hydrogen bonding and, therefore, higher electrophilicity than BHTOH-QM. BPPOH-QM was synthesized and its reactivity with water, methanol, and glutathione determined to be >10-fold higher than that of BHTOH-QM. The conversions of BPPOH and BHTOH to quinone methides in lung microsomes from male BALB/cByJ mice were quantitatively similar, but in vivo the former was pneumotoxic at one-half of the dose required for the latter and one-eighth of the dose required for BHT, as determined by increased lung weight:body weight ratios following a single i.p. injection. Similar differences were found in the doses of BHT, BHTOH, or BPPOH required for tumor promotion after a single initiating dose of 3-methylcholanthrene followed by three weekly injections of the phenol. The downregulaton of calpain II, previously shown to accompany lung tumor promotion by BHT and BHTOH, also occurred with BPPOH. The correlation between biologic activities of these phenols and the reactivities of their corresponding quinone methides provides additional support for the role of BHTOH-QM as the principal metabolite
抗氧化剂BHT微胶囊化产品超微结构的测定%Study on Superstructure of Microencapsulated Antioxidant BHT
Institute of Scientific and Technical Information of China (English)
陈梅香
2012-01-01
Scanning electron microscopy (SEM) was applied to study the superstructure of microencapsulated star butylated hydroxytoluene (BHT) manufactured by various preparation techniques. The results showed that preparation techniques had significant effects on the structure of microencapsulated products, and thus affected the qualities of products. The research about superstructure of BHT could provide information for analyses on the quality of microencapsulate products.%用扫描电子显微镜(SEM)研究抗氧化剂二丁基羟基甲苯(BHT)微胶囊化产品的超微结构.观察了喷雾干燥法不同壁材组成和工艺条件下制作的微胶囊化产品的表面结构和内部结构,同时考察了喷雾干燥进风温度对微胶囊化产品膜结构的影响.结果表明,不同壁材组成和工艺条件下制作的微胶囊化产品的超微结构有较大差异,合适的壁材组成和工艺条件有利于提高产品质量,同时喷雾干燥进风温度对微胶囊化产品的结构有很大影响,从而也影响到产品的质量.微胶囊化产品超微结构的研究为分析影响产品质量的因素提供了重要依据.
Bergshoeff, E.; Pope, C.N.; Stelle, K.S.
1990-01-01
We discuss the notion of higher-spin covariance in w∞ gravity. We show how a recently proposed covariant w∞ gravity action can be obtained from non-chiral w∞ gravity by making field redefinitions that introduce new gauge-field components with corresponding new gauge transformations.
Massive "spin-2" theories in arbitrary $D \\ge 3$ dimensions
Dalmazi, D; Mendonça, E L
2014-01-01
Here we show that in arbitrary dimensions $D\\ge 3$ there are two families of second order Lagrangians describing massive "spin-2" particles via a nonsymmetric rank-2 tensor. They differ from the usual Fierz-Pauli theory in general. At zero mass one of the families is Weyl invariant. Such massless theory has no particle content in $D=3$ and gives rise, via master action, to a dual higher order (in derivatives) description of massive spin-2 particles in $D=3$ where both the second and the fourth order terms are Weyl invariant, contrary to the linearized New Massive Gravity. However, only the fourth order term is invariant under arbitrary antisymmetric shifts. Consequently, the antisymmetric part of the tensor $e_{[\\mu\
A Massive-born Neutron Star with a Massive White Dwarf Companion
Cognard, Ismaël; Freire, Paulo C. C.; Guillemot, Lucas; Theureau, Gilles; Tauris, Thomas M.; Wex, Norbert; Graikou, Eleni; Kramer, Michael; Stappers, Benjamin; Lyne, Andrew G.; Bassa, Cees; Desvignes, Gregory; Lazarus, Patrick
2017-08-01
We report on the results of a 4 year timing campaign of PSR J2222-0137, a 2.44 day binary pulsar with a massive white dwarf (WD) companion, with the Nançay, Effelsberg, and Lovell radio telescopes. Using the Shapiro delay for this system, we find a pulsar mass m p = 1.76 ± 0.06 M ⊙ and a WD mass m c = 1.293 ± 0.025 M ⊙. We also measure the rate of advance of periastron for this system, which is marginally consistent with the general relativity prediction for these masses. The short lifetime of the massive WD progenitor star led to a rapid X-ray binary phase with little (< 10-2 M ⊙) mass accretion onto the neutron star; hence, the current pulsar mass is, within uncertainties, its birth mass, which is the largest measured to date. We discuss the discrepancy with previous mass measurements for this system; we conclude that the measurements presented here are likely to be more accurate. Finally, we highlight the usefulness of this system for testing alternative theories of gravity by tightly constraining the presence of dipolar radiation. This is of particular importance for certain aspects of strong-field gravity, like spontaneous scalarization, since the mass of PSR J2222-0137 puts that system into a poorly tested parameter range.
Testing gravity theories using tensor perturbations
Lin, Weikang; Ishak, Mustapha
2016-12-01
Primordial gravitational waves constitute a promising probe of the very early Universe and the laws of gravity. We study in this work changes to tensor-mode perturbations that can arise in various proposed modified gravity theories. These include additional friction effects, nonstandard dispersion relations involving a massive graviton, a modified speed, and a small-scale modification. We introduce a physically motivated parametrization of these effects and use current available data to obtain exclusion regions in the parameter spaces. Taking into account the foreground subtraction, we then perform a forecast analysis focusing on the tensor-mode modified-gravity parameters as constrained by the future experiments COrE, Stage-IV and PIXIE. For a fiducial value of the tensor-to-scalar ratio r =0.01 , we find that an additional friction of 3.5-4.5% compared to GR will be detected at 3 -σ by these experiments, while a decrease in friction will be more difficult to detect. The speed of gravitational waves needs to be by 5-15% different from the speed of light for detection. We find that the minimum detectable graviton mass is about 7.8 - 9.7 ×10-33 eV , which is of the same order of magnitude as the graviton mass that allows massive gravity theories to produce late-time cosmic acceleration. Finally, we study the tensor-mode perturbations in modified gravity during inflation using our parametrization. We find that, in addition to being related to r , the tensor spectral index would be related to the friction parameter ν0 by nT=-3 ν0-r /8 . Assuming that the friction parameter is unchanged throughout the history of the Universe, and that ν0 is much larger than r , the future experiments considered here will be able to distinguish this modified-gravity consistency relation from the standard inflation consistency relation, and thus can be used as a further test of modified gravity. In summary, tensor-mode perturbations and cosmic-microwave-background B
Dengiz, Suat
2014-01-01
Weyl-invariant extensions of three-dimensional New Massive Gravity, generic n-dimensional Quadratic Curvature Gravity theories and three-dimensional Born-Infeld gravity theory are analyzed in details. As required by Weyl-invariance, the actions of these gauge theories do not contain any dimensionful parameter hence the local symmetry is spontaneously broken in (Anti) de Sitter vacua in complete analogy with the Standard Model Higgs mechanism. In flat vacuum, symmetry breaking mechanism is more complicated: The dimensionful parameters come from dimensional transmutation in the quantum field theory; therefore, the conformal symmetry is radiatively broken (at two loop level in 3-dimensions and at one-loop level in 4-dimensions) \\`{a} la Coleman-Weinberg mechanism. In the broken phases, save for New Massive Gravity, the theories generically propagate with a unitary (tachyon and ghost-free) massless tensor, massive (or massless) vector and massless scalar particles for the particular intervals of the dimensionless...
Quantum Gravito-Optics: A Light Route from Semiclassical Gravity to Quantum Gravity
Unnikrishnan, C S
2015-01-01
Quantum gravity remains an elusive theory, in spite of our thorough understanding of the quantum theory and the general theory of relativity separately, presumably due to the lack of any observational clues. We argue that the theory of quantum gravity has a strong constraining anchor in the sector of gravitational radiation ensuring reliable physical clues, albeit in a limited observable form. In particular, all types of gravitational waves expected to be observable in LIGO-like advanced detectors are fully quantum mechanical states of radiation. Exact equivalence of the full quantum gravity theory with the familiar semiclassical theory is ensured in the radiation sector, in most real situations where the relevant quantum operator functions are normal ordered, by the analogue of the optical equivalence theorem in quantum optics. We show that this is indeed the case for detection of the waves from a massive binary system, a single gravitational atom, that emits coherent radiation. The idea of quantum-gravitati...
Spectral modelling of massive binary systems
Palate, Matthieu; Koenigsberger, Gloria; Moreno, Edmundo
2013-01-01
Aims: We simulate the spectra of massive binaries at different phases of the orbital cycle, accounting for the gravitational influence of the companion star on the shape and physical properties of the stellar surface. Methods: We used the Roche potential modified to account for radiation pressure to compute the stellar surface of close circular systems and we used the TIDES code for surface computation of eccentric systems. In both cases, we accounted for gravity darkening and mutual heating generated by irradiation to compute the surface temperature. We then interpolated NLTE plane-parallel atmosphere model spectra in a grid to obtain the local spectrum at each surface point. We finally summed all contributions, accounting for the Doppler shift, limb-darkening, and visibility to obtain the total synthetic spectrum. We computed different orbital phases and sets of physical and orbital parameters. Results: Our models predict line strength variations through the orbital cycle, but fail to completely reproduce t...
Gravity localization on hybrid branes
Energy Technology Data Exchange (ETDEWEB)
Veras, D.F.S., E-mail: franklin@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Caixa Postal 6030, 60455-760, Fortaleza, Ceará (Brazil); Cruz, W.T., E-mail: wilamicruz@gmail.com [Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE), Campus Juazeiro do Norte, 63040-540 Juazeiro do Norte, Ceará (Brazil); Maluf, R.V., E-mail: r.v.maluf@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Caixa Postal 6030, 60455-760, Fortaleza, Ceará (Brazil); Almeida, C.A.S., E-mail: carlos@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Caixa Postal 6030, 60455-760, Fortaleza, Ceará (Brazil)
2016-03-10
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.
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.
Gravity, holography and applications to condensed matter
Baggioli, Matteo
2016-01-01
Momentum relaxation is an ever-present and unavoidable ingredient of any realistic condensed matter system. In real-world materials the presence of a lattice, impurities or disorder forces momentum to dissipate and leads to relevant physical effects such as the finiteness of the DC transport properties, i.e. conductivities. The main purpose of this thesis is the introduction of momentum dissipation and its consequent effects into the framework of AdS/CMT, namely the applications of the gauge-gravity duality to condensed matter. A convenient and effective way of breaking the translational symmetry associated to such a conservation law is provided by massive gravity (MG) bulk theories. We consider generic massive gravity models embedded into asymptotically Anti de Sitter spacetime and we analyze them using holographic techniques. We study in detail their consistency and stability. We then focus our attention on the transport properties of the CFT duals. A big part of our work is devoted to the analysis of the e...
Quantization of Emergent Gravity
Yang, Hyun Seok
2013-01-01
Emergent gravity is based on a novel form of the equivalence principle known as the Darboux theorem or the Moser lemma in symplectic geometry stating that the electromagnetic force can always be eliminated by a local coordinate transformation as far as spacetime admits a symplectic structure, in other words, a microscopic spacetime becomes noncommutative (NC). If gravity emerges from U(1) gauge theory on NC spacetime, this picture of emergent gravity suggests a completely new quantization scheme where quantum gravity is defined by quantizing spacetime itself, leading to a dynamical NC spacetime. Therefore the quantization of emergent gravity is radically different from the conventional approach trying to quantize a phase space of metric fields. This approach for quantum gravity allows a background independent formulation where spacetime as well as matter fields is equally emergent from a universal vacuum of quantum gravity.
Quantization of emergent gravity
Yang, Hyun Seok
2015-02-01
Emergent gravity is based on a novel form of the equivalence principle known as the Darboux theorem or the Moser lemma in symplectic geometry stating that the electromagnetic force can always be eliminated by a local coordinate transformation as far as space-time admits a symplectic structure, in other words, a microscopic space-time becomes noncommutative (NC). If gravity emerges from U(1) gauge theory on NC space-time, this picture of emergent gravity suggests a completely new quantization scheme where quantum gravity is defined by quantizing space-time itself, leading to a dynamical NC space-time. Therefore the quantization of emergent gravity is radically different from the conventional approach trying to quantize a phase space of metric fields. This approach for quantum gravity allows a background-independent formulation where space-time and matter fields are equally emergent from a universal vacuum of quantum gravity.
Shendure, Jay; Fields, Stanley
2016-06-01
Human genetics has historically depended on the identification of individuals whose natural genetic variation underlies an observable trait or disease risk. Here we argue that new technologies now augment this historical approach by allowing the use of massively parallel assays in model systems to measure the functional effects of genetic variation in many human genes. These studies will help establish the disease risk of both observed and potential genetic variants and to overcome the problem of "variants of uncertain significance." Copyright © 2016 by the Genetics Society of America.
Handayani, S.; Dani, I. C.; Budiawan; Pakuanisa, D.
2017-05-01
The research of DNA adduct formation 8-hydroxy-2’-Deoxyguanosine (8-OHdG) as a biomarker of DNA damage due to oxidative stress was carried out by reacting the DNA base 2’-deoxyguanosine-5’-monophosphate with TBHQ and BHT. The formationof 8-OHdG was carried out in various conditions, at temperature of 37° C and 60° C, pH 7.4 and pH 8.4, within 5 hours of incubation time and in the addition of FeSO4. The formation of DNA adducts profile were analyzed using reversed phase HPLC with UV detector at a wavelength of 254 nm. The results of the study showed that TBHQ and BHT can trigger the formation of 8-OHdG from the reaction of 2’-hydroxy Deoxyguanosine-5’-monophosphate in the presence of Fe (II). Meanwhile, in the addition of hydrogen peroxide, the formation of DNA adducts only occur in the test substance TBHQ. The results showed that the condition of higher temperature at 60°C and pH 8,4 affects the higher formation of DNA adducts.
Seiss, Mario; Langer, Christopher; Hickel, Reinhard; Reichl, Franz-Xaver
2009-12-01
This study investigated the leaching of ingredients from several commercial dental composite resins cured with LED, and immersed in methanol or water for 24 h, respectively. The composites used were: Admira Dentin (VOCO), Artemis Schmelz (Enamel) (Ivoclar Vivadent), Els extra low shrinkage (Saremco Dental), Filtek Supreme XT Dentin (3 M ESPE), Gradia Direct (GC), Venus & Venus flow (Heraeus Kulzer), and XRV Herculite Prodigy Enamel (Kerr). From each dental composite four specimens with defined structure and 100-mg net weight were made. After the polymerization process, according to manufacturer's instructions, the specimens were immersed in either 1 ml water or 1 ml methanol and incubated at 37 degrees C for 24 h. Eluted ingredients triethyleneglycoldimethacrylate (TEGDMA), 2,6-di-tert-butyl-4-methylphenol (BHT), and 4-N,N-dimethylaminobenzoicacidethylester (DMABEE) were detected and quantified using gas chromatography-mass spectrometry (GC-MS). The amounts of the detected analytes from 100 mg polymerized composites ranged between the following values: TEGDMA: 0-0.5 mg (water), 0-1.6 mg (methanol); BHT: 0-0.03 μg (water), 0-0.11 mg (methanol); and DMABEE: 0-0.11 mg (water), 0-1.4 mg (methanol). We conclude from the results that the elution rates into methanol and water differ significantly. Furthermore, it is concluded that all the determined amounts eluting from the composites are far below toxic-relevant concentrations.
Massive star forming environments
Devine, Kathryn Elizabeth
2010-12-01
We present a study of the earliest stages of massive star formation, in which we focus on Infrared Dark Clouds (IRDCs) and young massive clusters. We present Very Large Array spectral line observations of ammonia (NH 3) and CCS toward four IRDCs. The NH3 lines provide diagnostics of the temperature and density structure within IRDCs. Based upon the NH 3 column density, IRDCs have masses of ˜ 103 to 10 4 M⊙ . We detect twenty NH3 clumps within four IRDCs, with radii regions are presented from the Near Infrared Imager (NIRIM) camera on the 3.5 m WIYN telescope. We report J, H, and K' band photometry in the clusters AFGL437, AFGL5180, and AFGL5142 and use these results to probe the stellar populations, extinction, and ages of the clusters. We find that all three clusters suffer significant extinction (AK ˜1), have ages ≤ 5 Myr, and are actively forming stars. We conclude that the properties of these embedded clusters are consistent with their evolving from IRDC clumps.
Three-dimensional Gravity, Holography and Black Holes
Lashkari, Nima
Gauge/gravity dualities and the matrix model provide us with exploratory frameworks for the study of quantum gravity (QG) in the presence of a cosmological constant that is negative or zero, respectively. Currently, in all the known examples instring theory, the gravity theory contains complicated matter fields and interactions. However, the idea of describing theories of quantum gravity in terms of dual non-gravitational theories, i.e. holography, has proven to go well beyond these examples. Motivated by holography, in the course of this thesis we explore simple models of quantum gravity with the goal of obtaining insight into non-perturbative QG, in particular the physics of black holes. We consider three-dimensional gravity with a negative cosmological constant. Weuse Ricci flow techniques to study flows between the potential vacua of topologically massive gravity and show that for large values of the Chern-Simons coupling anti-de Sitter space is the ground state. Moreover, we study spontaneous symmetry-breaking in vacua of theories of gravity coupled to scalars and gauge fields and find examples of discrete symmetry-breaking phases with exotic thermodynamic properties. We study three-dimensional gravity with a positive cosmological constant as a theory of quantum cosmology. We compute the full non-perturbative Euclidean partition function of de Sitter gravity by evaluating the gravity path integral on physically relevant Euclidean continuations of the static patch. The partition function diverges in a non-regularizable way and we interpret this as a hint that the theory does not exist at a quantum level. As we show however, the inclusion of the simplest form of interaction, the Chern-Simons term, removes the undesirable divergences.
Cosmological consequences of Modified Gravity (MOG)
Toth, Viktor T
2010-01-01
As an alternative to the LCDM concordance model, Scalar-Tensor-Vector Modified Gravity (MOG) theory reproduces key cosmological observations without postulating the presence of an exotic dark matter component. MOG is a field theory based on an action principle, with a variable gravitational constant and a repulsive vector field with variable range. MOG yields a phenomenological acceleration law that includes strong tensorial gravity partially canceled by a repulsive massive vector force. This acceleration law can be used to model the CMB acoustic spectrum and the matter power spectrum yielding good agreement with observation. A key prediction of MOG is the presence of strong baryonic oscillations, which will be detectable by future surveys. MOG is also consistent with Type Ia supernova data. We also describe on-going research of the coupling between MOG and continuous matter, consistent with the weak equivalence principle and solar system observations.