Photonic processes in Born-Infeld theory
NASA Astrophysics Data System (ADS)
Dávila, José Manuel; Schubert, Christian; Trejo, María Anabel
2014-12-01
We study the processes of photon-photon scattering and photon splitting in a magnetic field in Born-Infeld theory. In both cases we combine the terms from the tree-level Born-Infeld Lagrangian with the usual one-loop QED contributions, where those are approximated by the Euler-Heisenberg Lagrangian, including also the interference terms. For photon-photon scattering we obtain the total cross-section in the low-energy approximation. For photon splitting we compute the total absorption coefficient in the hexagon (weak field) approximation, and also show that, due to the non-birefringence property of Born-Infeld theory, the selection rules found by Adler for the QED case continue to hold in this more general setting. We discuss the bounds on the free parameter of Born-Infeld theory that may be obtained from this type of processes.
Wormholes in Einstein-Born-Infeld theory
Richarte, Martin G.; Simeone, Claudio
2009-11-15
Spherically symmetric thin-shell wormholes are studied within the framework of Einstein-Born-Infeld theory. We analyze the exotic matter content, and find that for certain values of the Born-Infeld parameter the amount of exotic matter on the shell can be reduced in relation to the Maxwell case. We also examine the mechanical stability of the wormhole configurations under radial perturbations preserving the spherical symmetry. In addition, in the Appendix the repulsive or attractive character of the wormhole geometries is briefly discussed.
Flux compactifications in Einstein-Born-Infeld theories
NASA Astrophysics Data System (ADS)
Ramadhan, Handhika S.; Cahyo, Brian A.; Iqbal, Muhammad
2015-07-01
We investigate the flux compactification mechanism in simple toy models of Einstein-Born-Infeld theories. These are the direct generalizations of the Einstein-Maxwell flux compactifications that recently gained fame as a toy model for tunneling in the landscape. Our investigation reveals that the Born-Infeld form does not significantly modify the qualitative result of the Einstein-Maxwell theory. For the case of Einstein-Higgs theory, however, we found that the effect of Born-Infeld nonlinearity is to render all q >1 extradimensional compactification unstable against semiclassical tunneling to nothing.
Static potential in a topologically massive Born-Infeld theory
NASA Astrophysics Data System (ADS)
Gaete, Patricio
2004-03-01
For a (2+1)-dimensional topologically massive Born-Infeld theory, we compute the interaction potential within the structure of the gauge-invariant but path-dependent variables formalism. The result is equivalent to that of QED3 with a Thirring interaction term among fermions, in the short distance regime.
Dualities in M-theory and Born-Infeld Theory
Brace, Daniel, M
2001-08-01
We discuss two examples of duality. The first arises in the context of toroidal compactification of the discrete light cone quantization of M-theory. In the presence of nontrivial moduli coming from the M-theory three form, it has been conjectured that the system is described by supersymmetric Yang-Mills gauge theory on a noncommutative torus. We are able to provide evidence for this conjecture, by showing that the dualities of this M-theory compactification, which correspond to T-duality in Type IIA string theory, are also dualities of the noncommutative supersymmetric Yang-Mills description. One can also consider this as evidence for the accuracy of the Matrix Theory description of M-theory in this background. The second type of duality is the self-duality of theories with U(1) gauge fields. After discussing the general theory of duality invariance for theories with complex gauge fields, we are able to find a generalization of the well known U(1) Born-Infeld theory that contains any number of gauge fields and which is invariant under the maximal duality group. We then find a supersymmetric extension of our results, and also show that our results can be extended to find Born-Infeld type actions in any even dimensional spacetime.
Rotating black branes in Brans-Dicke-Born-Infeld theory
NASA Astrophysics Data System (ADS)
Hendi, S. H.
2008-08-01
In this paper, we present a new class of charged rotating black brane solutions in the higher dimensional Brans-Dicke-Born-Infeld theory and investigate their properties. Solving the field equations directly is a nontrivial task because they include the second derivatives of the scalar field. We remove this difficulty through a conformal transformation. Also, we find that the suitable Lagrangian of Einstein-Born-Infeld-dilaton gravity is not the same as presented by Dehghani et al. [J. Cosmol. Astropart. Phys. 0702, 020 (2007)]. We show that the given solutions can present black brane, with inner and outer event horizons, an extreme black brane, or a naked singularity provided the parameters of the solutions are chosen suitably. These black brane solutions are neither asymptotically flat nor (anti-)de Sitter. Then we calculate finite Euclidean action, the conserved, and thermodynamic quantities through the use of counterterm method. Finally, we argue that these quantities satisfy the first law of thermodynamics, and the entropy does not follow the area law.
c-Map for Born-Infeld theories
NASA Astrophysics Data System (ADS)
Andrianopoli, L.; D'Auria, R.; Ferrara, S.; Trigiante, M.
2016-07-01
The c-map of four dimensional non-linear theories of electromagnetism is considered both in the rigid case and in its coupling to gravity. In this way theories with antisymmetric tensors and scalars are obtained, and the three non-linear representations of N = 2 supersymmetry partially broken to N = 1 related. The manifest Sp (2 n) and U (n) covariance of these theories in their multifield extensions is also exhibited. This construction extends to H-invariant non-linear theories of Born-Infeld type with non-dynamical scalars spanning a symmetric coset manifold G/H and the vector field strengths and their duals in a symplectic representation of G as is the case for extended supergravity.
Eddington-Born-Infeld theory and the dark sector
NASA Astrophysics Data System (ADS)
Skordis, Constantinos
2009-10-01
I consider a unified description of the phenomena of dark matter and dark energy which is given by a simple modification of gravity. Gravity is modified with new degrees of freedom which come from a second connection, different from the usual Levi-Civita connection. A candidate action, the Eddington-Born-Infeld action (EBI) for these degrees of freedom was proposed by Bañados and is shown to be dual to a theory with two metrics called bi-gravity. This modification directly gives solutions to the field equations which mimic dark matter for spherically symmetric systems while for cosmological spacetimes it gives, in addition, the effect of dark energy. I shall further show that the effect of dark matter is present even at the linearized cosmological level and that this makes it in harmony with all known large scale cosmological observations.
Corrected Article: Wormholes in Einstein-Born-Infeld theory [Phys. Rev. D 80, 104033 (2009)
Richarte, Martin G.; Simeone, Claudio
2010-05-15
Spherically symmetric thin-shell wormholes are studied within the framework of Einstein-Born-Infeld theory. We analyze the exotic matter content, and find that for certain values of the Born-Infeld parameter the amount of exotic matter on the shell can be reduced in relation with the Maxwell case. We also examine the mechanical stability of the wormhole configurations under radial perturbations preserving the spherical symmetry.
Analysis of regularizing properties of nonlinear electrodynamics in the Einstein-Born-Infeld theory
Denisov, V. I. Sokolov, V. A.
2011-12-15
New regularizing manifestations of the Einstein-Born-Infeld theory for a massive charged force center in the space-time are considered. The properties of isotropic geodesics in this space are analyzed. It is shown that the charge may exceed the maximum possible charge in the Reissner-Nordstroem solution; the possibility of eliminating one of the metric horizons is also noted.
Solitons and black holes in non-Abelian Einstein-Born-Infeld theory
NASA Astrophysics Data System (ADS)
Dyadichev, V. V.; Gal'tsov, D. V.
2000-08-01
Recently it was shown that the Born-Infeld modification of the quadratic Yang-Mills action gives rise to classical particle-like solutions in the flat space which have a striking similarity with the Bartnik-McKinnon solutions obtained within the gravity coupled Yang-Mills theory. We show that both families of solutions are continuously related within the framework of the Einstein-Born-Infeld theory via interpolating sequences of parameters. We also investigate an internal structure of the associated black holes and find that the Born-Infeld non-linearity changes drastically the black hole interior typical for the usual quadratic Yang-Mills theory. In the latter case a generic solution exhibits violent metric oscillations near the singularity. In the Born-Infeld case the generic interior solution is smooth, the metric tends to the standard Schwarzschild type singularity, and we did not observe internal horizons. Smoothing of the `violent' EYM singularity may be interpreted as a result of non-gravitational quantum effects.
Anisotropic power-law solutions for a supersymmetry Dirac-Born-Infeld theory
NASA Astrophysics Data System (ADS)
Do, Tuan Q.; Kao, W. F.
2016-04-01
A new set of Bianchi type I power-law expanding solutions is obtained for a supersymmetric Dirac-Born-Infeld (SDBI) theory coupled to a gauge field. Stability analysis is also performed to show that this set of power-law expanding solutions is stable. In particular, this set of power-law solutions provides an explicit example to the role played by the supersymmetry correction term. We also show by a general approach that any stable anisotropic solution of SDBI model will turn unstable when a phantom field is introduced. We also show that the result of the scalar perturbation indicates that the SDBI model is a realistic model.
NASA Astrophysics Data System (ADS)
Bernardini, Alex Eduardo; Bertolami, Orfeu
An equivalence between Born-Infeld and effective real scalar field theories for brane structures is built in some specific warped space-time scenarios. Once the equations of motion for tachyon fields related to the Born-Infeld action are written as first-order equations, a simple analytical connection with a particular class of real scalar field superpotentials can be found. This equivalence leads to the conclusion that, for a certain class of superpotentials, both systems can support identical thick brane solutions as well as brane structures described through localized energy densities, T_{00}(y), in the 5(th) dimension, y. Our results indicate that thick brane solutions realized by the Born-Infeld cosmology can be connected to real scalar field brane scenarios which can be used to effectively map the tachyon condensation mechanism, which is relevant in several dark sector scenarios.
Hyperons in neutron stars within an Eddington-inspired Born-Infeld theory of gravity
NASA Astrophysics Data System (ADS)
Qauli, A. I.; Iqbal, M.; Sulaksono, A.; Ramadhan, H. S.
2016-05-01
We investigate the mass-radius relation of the neutron star (NS) with hyperons inside its core by using the Eddington-inspired Born-Infeld (EiBI) theory of gravity. The equation of state of the star is calculated by using the relativistic mean field model under which the standard SU(6) prescription and hyperon potential depths are used to determine the hyperon coupling constants. We found that, for 4 ×106 m2≲κ ≲6 ×106 m2 , the corresponding NS mass and radius predicted by the EiBI theory of gravity is compatible with observational constraints of maximum NS mass and radius. The corresponding κ value is also compatible with the κ range predicted by the astrophysical-cosmological constraints. We also found that the parameter κ could control the size and the compactness of a neutron star.
Duality rotations and type D solutions of Einstein-Born-Infeld theory
NASA Astrophysics Data System (ADS)
Salazar, H.; Garcia, A.; Plebanski, J. F.
Explicit type D solutions, which generalize the charged Taub-NUT metric with cosmological constant, are constructed within nonlinear electrodynamics of the Born-Infeld type, constrained by the condition that freedom of duality rotations is included. The Carter (+,-) type D separable metrics in an optimal coordinatization is discussed, and the nonlinear electrodynamics in general relativity is described in terms of the null tetrad formalism. The class of nonlinear theories endowed with the freedom of duality rotations is defined. It is shown that B(+,-) branches are indeed carriers of solutions to the dynamical scheme of nonlinear electrodynamics, deriving explicit solutions which generalize the Taub-NUT charged solutions with lambda for the case of 'nonlinear charges'.
A survey of solutions in a gravitational Born-Infeld theory
Chern, Jann-Long Yang, Sze-Guang
2014-03-15
An elliptic equation that arises from a cosmic string model with the action of the Born-Infeld nonlinear electromagnetism, is considered. We classify and establish the uniqueness of radially symmetric solutions.
Is Eddington-Born-Infeld theory really free of cosmological singularities?
NASA Astrophysics Data System (ADS)
Bouhmadi-López, Mariam; Chen, Che-Yu; Chen, Pisin
2014-03-01
The Eddington-inspired-Born-Infeld (EiBI) theory has recently been resurrected. Such a theory is characterized by being equivalent to Einstein theory in vacuum but differing from it in the presence of matter. One of the virtues of the theory is that it avoids the Big Bang singularity for a radiation-filled universe. In this paper, we analyze singularity avoidance in this kind of model. More precisely, we analyze the behavior of a homogeneous and isotropic universe filled with phantom energy in addition to the dark and baryonic matter. Unlike the Big Bang singularity that can be avoided in this kind of model through a bounce or a loitering effect on the physical metric, we find that the Big Rip singularity is unavoidable in the EiBI phantom model even though it can be postponed towards a slightly further future cosmic time as compared with the same singularity in other models based on the standard general relativity and with the same matter content as described above.
Cosmology in a reduced Born-Infeld f (T ) theory of gravity
NASA Astrophysics Data System (ADS)
Jana, Soumya
2014-12-01
A perfect fluid, spatially flat cosmology in a f (T ) model, derived from a recently proposed general Born-Infeld-type theory of gravity is studied. Four-dimensional cosmological solutions are obtained assuming the equation of state p =ω ρ . For a positive value of λ (a parameter in the theory) the solution is singular (of the big bang type) but may have accelerated expansion at an early stage. For λ <0 there exists a nonzero minimum scale factor and a finite maximum value of the energy density, but the curvature scalar diverges. Interestingly, for λ <0 , the Universe may undergo an eternal accelerated expansion with a de Sitter expansion phase at late times. We find these features without considering any extra matter field or even negative pressure. Fitting our model with supernova data we find that the simplest dust model (p =0 ), with λ >0 , is able to generate acceleration and fits well, although the resulting properties of the Universe differ much from the known, present day, accepted values. The best fit model requires (with λ >0 ) an additional component of the physical matter density, with a negative value of the equation of state parameter, along with dust. The λ <0 solutions do not fit well with observations. Though these models do not explain the dark energy problem with consistency, their analysis does shed light on the plausibility of an alternative geometrical explanation.
Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram
2010-05-15
We define various Born-Infeld gravity theories in 3+1 dimensions which reduce to Horava's model at the quadratic level in small curvature expansion. In their exact forms, our actions provide z{yields}{infinity} extensions of Horava's gravity, but when small curvature expansion is used, they reproduce finite z models, including some half-integer ones.
Dyonic (A)dS black holes in Einstein-Born-Infeld theory in diverse dimensions
NASA Astrophysics Data System (ADS)
Li, Shoulong; Lü, H.; Wei, Hao
2016-07-01
We study Einstein-Born-Infeld gravity and construct the dyonic (A)dS planar black holes in general even dimensions, that carry both the electric charge and magnetic fluxes along the planar space. In four dimensions, the solution can be constructed with also spherical and hyperbolic topologies. We study the black hole thermodynamics and obtain the first law. We also classify the singularity structure.
Comment on "Extended Born-Infeld theory and the bouncing magnetic universe"
NASA Astrophysics Data System (ADS)
García-Salcedo, Ricardo; Gonzalez, Tame; Horta-Rangel, Antonio; Quiros, Israel
2014-12-01
In a recent paper [Phys. Rev. D 85, 023528 (2012), 10.1103/PhysRevD.85.023528] the authors proposed a generalized Born-Infeld electrodynamics coupled to general relativity which produces a nonsingular bouncing universe. For a magnetic universe the resulting cosmic evolution inevitably interpolates between asymptotic de Sitter states. Here we show that (i) the conclusion about the inevitability of the asymptotic vacuum regime in a magnetic universe is wrong, (ii) a sudden curvature singularity—not better than the big bang—arises, but for spaces of positive curvature, (iii) the square sound speed can be a negative quantity, signaling instability against small perturbations of the background energy density, and (iv) the speed of sound can exceed the speed of light, which raises a causality issue.
Black holes in Born-Infeld extended new massive gravity
Ghodsi, Ahmad; Yekta, Davood Mahdavian
2011-05-15
In this paper we find different types of black holes for the Born-Infeld extended new massive gravity. Our solutions include (un)charged warped (anti-)de Sitter black holes for four and six derivative expanded action. We also look at the black holes in unexpanded Born-Infeld action. In each case we calculate the entropy, angular momentum and mass of the black holes. We also find the central charges for the conformal field theory duals.
Dirac-born-infeld and k-inflation: The CMB anisotropies from string theory
NASA Astrophysics Data System (ADS)
Ringeval, Christophe
2010-01-01
Inflationary models within string theory exhibit unusual scalar field dynamics involving non-minimal kinetic terms and generically referred to as k-inflation. In this situation, the standard slow-roll approach used to determine the behavior of the primordial cosmological perturbations cannot longer be used. We present a generic method, based on the uniform approximation, to analytically derive the primordial power spectra of scalar and tensor perturbations. At leading order, the scalar spectral index, its running and the tensor-to-scalar ratio are modified by the new dynamics. We provide their new expression, correct previous results at next-to-leading order and clarify the definition of what is the tensor-to-scalar ratio when the sound horizon and Hubble radius are not the same. Finally, we discuss the constraints the parameters encoding the non-minimal kinetic terms have to satisfy, such as the sound speed and the energy scale of k-inflation, in view of the fifth year Wilkinson Microwave Anisotropy Probe (WMAP5) data.
Anisotropy in Born-Infeld brane cosmology
Haghani, Zahra; Sepangi, Hamid Reza; Shahidi, Shahab
2011-03-15
The accelerated expansion of the Universe together with its present day isotropy has posed an interesting challenge to the numerous model theories presented over the years to describe them. In this paper, we address the above questions in the context of a braneworld model where the Universe is filled with Born-Infeld matter. We show that in such a model, the Universe evolves from a highly anisotropic state to its present isotropic form, which has entered an accelerated expanding phase.
Nonsingular promises from Born-Infeld gravity.
Fiorini, Franco
2013-07-26
Born-Infeld determinantal gravity formulated in Weitzenböck spacetime is discussed in the context of Friedmann-Robertson-Walker (FRW) cosmologies. It is shown how the standard model big bang singularity is absent in certain spatially flat FRW spacetimes, where the high energy regime is characterized by a de Sitter inflationary stage of geometrical character, i.e., without the presence of the inflaton field. This taming of the initial singularity is also achieved for some spatially curved FRW manifolds where the singularity is replaced by a de Sitter stage or a big bounce of the scale factor depending on certain combinations of free parameters appearing in the action. Unlike other Born-Infeld-like theories in vogue, the one here presented is also capable of deforming vacuum general relativistic solutions. PMID:23931349
Nonsingular Promises from Born-Infeld Gravity
NASA Astrophysics Data System (ADS)
Fiorini, Franco
2013-07-01
Born-Infeld determinantal gravity formulated in Weitzenböck spacetime is discussed in the context of Friedmann-Robertson-Walker (FRW) cosmologies. It is shown how the standard model big bang singularity is absent in certain spatially flat FRW spacetimes, where the high energy regime is characterized by a de Sitter inflationary stage of geometrical character, i.e., without the presence of the inflaton field. This taming of the initial singularity is also achieved for some spatially curved FRW manifolds where the singularity is replaced by a de Sitter stage or a big bounce of the scale factor depending on certain combinations of free parameters appearing in the action. Unlike other Born-Infeld-like theories in vogue, the one here presented is also capable of deforming vacuum general relativistic solutions.
Born-Infeld gravity in three dimensions
Alishahiha, Mohsen; Naseh, Ali; Soltanpanahi, Hesam
2010-07-15
In this paper we explore different aspects of three dimensional Born-Infeld as well as Born-Infeld-Chern-Simons gravity. We show that the models have anti-de Sitter and anti-de Sitter wave vacuum solutions. Moreover, we observe that although Born-Infeld-Chern-Simons gravity admits a logarithmic solution, Born-Infeld gravity does not, though it has a limiting logarithmic solution as we approach the critical point.
Born-Infeld gravity coupled to Born-Infeld electrodynamics
NASA Astrophysics Data System (ADS)
Jana, Soumya; Kar, Sayan
2015-10-01
We investigate spherically symmetric, static spacetimes in Eddington-inspired Born-Infeld gravity coupled to Born-Infeld electrodynamics. The two constants, b2 and κ which parametrize the Born-Infeld structures in the electrodynamics (matter) and gravity sectors, characterize the features of our analytical solutions. Black holes or naked singularities are found to arise, depending on the values of b2 and κ , as well as charge and mass. Several such solutions are classified and understood through the analysis of the associated metric functions for fixed κ , varying b2 and vice versa. Further, we also compare the new metric functions with those for the known b2→∞ (Maxwell) and the κ →0 (geonic black hole) cases. Interestingly, for a particular relation between these two parameters, b2=1 /4 κ , κ >0 , we obtain a solution resembling the well-known Reissner-Nordström line element, albeit some modifications. Using this particular solution as the background spacetime, we study null geodesics for Born-Infeld photons and also gravitational lensing. Among the interesting features we note (i) an increase in the radius of the photon sphere with increasing κ and (ii) a net positive contribution in the leading order correction term involving κ , in the weak lensing formula for the deflection angle. We also investigate the effective potential and light propagation for various other solutions through numerics and plots. In summary, our paper is the first attempt towards figuring out how Born-Infeld structures in both the matter and gravity sectors can influence the nature and character of resulting gravitational fields.
Exact solutions of Lovelock-Born-Infeld black holes
Aiello, Matias; Ferraro, Rafael; Giribet, Gaston
2004-11-15
The exact five-dimensional charged black hole solution in Lovelock gravity coupled to Born-Infeld electrodynamics is presented. This solution interpolates between the Hoffmann black hole for the Einstein-Born-Infeld theory and other solutions in the Lovelock theory previously studied in the literature. It is shown how the conical singularity of the metric around the origin can be removed by a proper choice of the black hole parameters. The differences existing with the Reissner-Nordstroem black holes are discussed. In particular, we show the existence of charged black holes with a unique horizon.
Wormhole geometries in Eddington-Inspired Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Harko, Tiberiu; Lobo, Francisco S. N.; Mak, M. K.; Sushkov, Sergey V.
2015-10-01
Eddington-inspired Born-Infeld (EiBI) gravity is a recently proposed modified theory of gravity, based on the classic work of Eddington and Born-Infeld nonlinear electrodynamics. In this paper, we consider the possibility that wormhole geometries are sustained in EiBI gravity. We present the gravitational field equations for an anisotropic stress-energy tensor and consider the generic conditions, for the auxiliary metric, at the wormhole throat. In addition to this, we obtain an exact solution for an asymptotically flat wormhole.
Preheating in Dirac-Born-Infeld inflation
Bouatta, Nazim; Davis, Anne-Christine; Ribeiro, Raquel H.; Seery, David E-mail: A.C.Davis@damtp.cam.ac.uk E-mail: D.Seery@sussex.ac.uk
2010-09-01
We study how the universe reheats following an era of chaotic Dirac-Born-Infeld inflation, and compare the rate of particle production with that in models based on canonical kinetic terms. Particle production occurs through non-perturbative resonances whose structure is modified by the nonlinearities of the Dirac-Born-Infeld action. We investigate these modifications and show that the reheating process may be efficient. We estimate the initial temperature of the subsequent hot, radiation-dominated phase.
Born-Infeld condensate as a possible origin of neutrino masses and dark energy
NASA Astrophysics Data System (ADS)
Addazi, Andrea; Capozziello, Salvatore; Odintsov, Sergei
2016-09-01
We discuss the possibility that a Born-Infeld condensate coupled to neutrinos can generate both neutrino masses and an effective cosmological constant. In particular, an effective field theory is provided capable of dynamically realizing the neutrino superfluid phase firstly suggested by Ginzburg and Zharkov. In such a case, neutrinos acquire a mass gap inside the Born-Infeld ether forming a long-range Cooper pair. Phenomenological implications of the approach are also discussed.
Born-Infeld thin-shell wormholes supported by generalized Cosmic Chaplygin gas
NASA Astrophysics Data System (ADS)
Azam, M.
2016-03-01
This paper investigates thin-shell wormholes in Born-Infeld theory supported by generalized Cosmic Chaplygin gas (GCCG). We study their stability via radial perturbations for distinct values of charge and Born-Infeld parameter. The comparison of wormhole solutions corresponding to generalized Chaplygin gas, modified Chaplygin gas with GCCG quation of state is established. It is found that similar type of wormhole solutions exists for small value of charge and Born-Infeld parameter for all type of equation of state, while some extra stable as well as unstable solution are found corresponding to large value of charge and Born-Infeld parameter. Thus, it is concluded that GCCG and large value of charge may responsible for such extra solutions.
Topological vortices in generalized Born-Infeld-Higgs electrodynamics
NASA Astrophysics Data System (ADS)
Casana, R.; Hora, E. da; Rubiera-Garcia, D.; Santos, C. dos
2015-08-01
A consistent BPS formalism to study the existence of topological axially symmetric vortices in generalized versions of the Born-Infeld-Higgs electrodynamics is implemented. Such a generalization modifies the field dynamics via the introduction of three nonnegative functions depending only in the Higgs field, namely, , , and . A set of first-order differential equations is attained when these functions satisfy a constraint related to the Ampère law. Such a constraint allows one to minimize the system's energy in such way that it becomes proportional to the magnetic flux. Our results provides an enhancement of the role of topological vortex solutions in Born-Infeld-Higgs electrodynamics. Finally, we analyze a set of models entailing the recovery of a generalized version of Maxwell-Higgs electrodynamics in a certain limit of the theory.
Extended Born-Infeld dynamics and cosmology
NASA Astrophysics Data System (ADS)
Novello, M.; Makler, M.; Werneck, L. S.; Romero, C. A.
2005-02-01
We introduce an extension of the Born-Infeld action for a scalar field and show that it can act as unifying dark matter, providing an explanation for both structure formation and the accelerated expansion of the universe. We investigate the cosmological dynamics of this theory in a particular case, referred to as the “Milne-Born-Infeld” (MBI) Lagrangian. We show that this model, whose equation of state has effectively a single free parameter, is consistent with recent type Ia supernovae data, providing a fit as good as for the ΛCDM model with the same number of degrees of freedom. Furthermore, this parameter is tightly constrained by current data, making the model easily testable with other observables. Contrary to previous candidates for unifying dark matter, the sound velocity of the MBI model is vanishing both close to the dark-matter state as well as near the cosmological constant state. This could avoid the problems on the matter power spectrum that were present in previous adiabatic dark-matter/dark-energy unification models. We also present a short discussion on the causal propagation in nonlinear scalar field theories such as the one proposed here.
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Tad, R. Moradi; Armanfard, Z.; Talezadeh, M. S.
2016-05-01
Motivated by a thermodynamic analogy of black holes and Van der Waals liquid/gas systems, in this paper, we study P- V criticality of both dilatonic Born-Infeld black holes and their conformal solutions, Brans-Dicke-Born-Infeld solutions. Due to the conformal constraint, we have to neglect the old Lagrangian of dilatonic Born-Infeld theory and its black hole solutions, and introduce a new one. We obtain spherically symmetric nonlinearly charged black hole solutions in both Einstein and Jordan frames and then we calculate the related conserved and thermodynamic quantities. After that, we extend the phase space by considering the proportionality of the cosmological constant and thermodynamical pressure. We obtain critical values of the thermodynamic coordinates through numerical methods and plot the relevant P- V and G- T diagrams. Investigation of the mentioned diagrams helps us to study the thermodynamical phase transition. We also analyze the effects of varying different parameters on the phase transition of black holes.
Surface singularities in Eddington-inspired Born-Infeld gravity.
Pani, Paolo; Sotiriou, Thomas P
2012-12-21
Eddington-inspired Born-Infeld gravity was recently proposed as an alternative to general relativity that offers a resolution of spacetime singularities. The theory differs from Einstein's gravity only inside matter due to nondynamical degrees of freedom, and it is compatible with all current observations. We show that the theory is reminiscent of Palatini f(R) gravity and that it shares the same pathologies, such as curvature singularities at the surface of polytropic stars and unacceptable Newtonian limit. This casts serious doubt on its viability. PMID:23368444
Approximated solutions to Born-Infeld dynamics
NASA Astrophysics Data System (ADS)
Ferraro, Rafael; Nigro, Mauro
2016-02-01
The Born-Infeld equation in the plane is usefully captured in complex language. The general exact solution can be written as a combination of holomorphic and anti-holomorphic functions. However, this solution only expresses the potential in an implicit way. We rework the formulation to obtain the complex potential in an explicit way, by means of a perturbative procedure. We take care of the secular behavior common to this kind of approach, by resorting to a symmetry the equation has at the considered order of approximation. We apply the method to build approximated solutions to Born-Infeld electrodynamics. We solve for BI electromagnetic waves traveling in opposite directions. We study the propagation at interfaces, with the aim of searching for effects susceptible to experimental detection. In particular, we show that a reflected wave is produced when a wave is incident on a semi-space containing a magnetostatic field.
On the Electrostatic Born-Infeld Equation with Extended Charges
NASA Astrophysics Data System (ADS)
Bonheure, Denis; d'Avenia, Pietro; Pomponio, Alessio
2016-02-01
In this paper, we deal with the electrostatic Born-Infeld equation (nablaφ/√{1-|nabla φ|^2} )= ρ quad{in} R^N, lim_{|x|to } φ(x)= 0, quad quad quad quad (BI) where {ρ} is an assigned extended charge density. We are interested in the existence and uniqueness of the potential {φ} and finiteness of the energy of the electrostatic field {-nabla φ} . We first relax the problem and treat it with the direct method of the Calculus of Variations for a broad class of charge densities. Assuming {ρ} is radially distributed, we recover the weak formulation of (BI) and the regularity of the solution of the Poisson equation (under the same smoothness assumptions). In the case of a locally bounded charge, we also recover the weak formulation without assuming any symmetry. The solution is even classical if {ρ} is smooth. Then we analyze the case where the density {ρ} is a superposition of point charges and discuss the results in (Kiessling, Commun Math Phys 314:509-523, 2012). Other models are discussed, as for instance a system arising from the coupling of the nonlinear Klein-Gordon equation with the Born-Infeld theory.
Cosmological singularities in Born-Infeld determinantal gravity
NASA Astrophysics Data System (ADS)
Bouhmadi-López, Mariam; Chen, Che-Yu; Chen, Pisin
2014-12-01
The Born-Infeld determinantal gravity has been recently proposed as a way to smooth the big bang singularity. This theory is formulated on the Weitzenböck space-time and the teleparallel representation is used instead of the standard Riemannian representation. We find that although this theory is shown to be singularity free for a certain region of the parameter space in which the divergence of the Hubble rate in the high-energy regime is substituted by a de Sitter stage or a bounce in a Friedmann-Lemaître-Robertson-Walker universe, cosmological singularities—such as a big rip, big bang, big freeze, and sudden singularities—can emerge in other regions of the configuration space of the theory. We also show that all these singular events exist even though the universe is filled with a perfect fluid with a constant equation of state.
Cascading dust inflation in Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Beltrán Jiménez, Jose; Heisenberg, Lavinia; Olmo, Gonzalo J.; Ringeval, Christophe
2015-11-01
In the framework of Born-Infeld inspired gravity theories, which deviates from General Relativity (GR) in the high curvature regime, we discuss the viability of Cosmic Inflation without scalar fields. For energy densities higher than the new mass scale of the theory, a gravitating dust component is shown to generically induce an accelerated expansion of the Universe. Within such a simple scenario, inflation gracefully exits when the GR regime is recovered, but the Universe would remain matter dominated. In order to implement a reheating era after inflation, we then consider inflation to be driven by a mixture of unstable dust species decaying into radiation. Because the speed of sound gravitates within the Born-Infeld model under consideration, our scenario ends up being predictive on various open questions of the inflationary paradigm. The total number of e-folds of acceleration is given by the lifetime of the unstable dust components and is related to the duration of reheating. As a result, inflation does not last much longer than the number of e-folds of deceleration allowing a small spatial curvature and large scale deviations to isotropy to be observable today. Energy densities are self-regulated as inflation can only start for a total energy density less than a threshold value, again related to the species' lifetime. Above this threshold, the Universe may bounce thereby avoiding a singularity. Another distinctive feature is that the accelerated expansion is of the superinflationary kind, namely the first Hubble flow function is negative. We show however that the tensor modes are never excited and the tensor-to-scalar ratio is always vanishing, independently of the energy scale of inflation.
Warm Dirac-Born-Infeld inflation
Cai Yifu; Dent, James B.; Easson, Damien A.
2011-05-15
We propose a warm inflationary model in the context of relativistic D-brane inflation in a warped throat, which has Dirac-Born-Infeld (DBI) kinetic term and is coupled to radiation through a dissipation term. The perturbation freezes at the sound horizon and the power spectrum is determined by a combination of the dissipative parameter and the sound speed parameter. The thermal dissipation ameliorates the eta problem and softens theoretical constraints from the extra-dimensional volume and from observational bounds on the tensor-to-scalar ratio. The warm DBI model can lead to appreciable non-Gaussianity of the equilateral type. As a phenomenological model, ignoring compactification constraints, we show that large-field warm inflation models do not necessarily yield a large tensor-to-scalar ratio.
Eddington-Born-Infeld gravity and the large scale structure of the Universe
NASA Astrophysics Data System (ADS)
Bañados, M.; Ferreira, P. G.; Skordis, C.
2009-03-01
It has been argued that a Universe governed by Eddington-Born-Infeld gravity can be compatible with current cosmological constraints. The extra fields introduced in this theory can behave as both dark matter and dark energy, unifying the dark sector in one coherent framework. We show the various roles the extra fields can play in the expansion of the Universe and study the evolution of linear perturbations in the various regimes. We find that, as a unified theory of the dark sector, Eddington-Born-Infeld gravity will lead to excessive fluctuations in the cosmic microwave background on large scales. In the presence of a cosmological constant, however, the extra fields can behave as a form of nonparticulate dark matter and can lead to a cosmology which is entirely compatible with current observations of large scale structure. We discuss the interpretation of this form of dark matter and how it can differ from standard, particulate dark matter.
FAST TRACK COMMUNICATION: Born-Infeld extension of new massive gravity
NASA Astrophysics Data System (ADS)
Güllü, İbrahim; Çaǧri Şişman, Tahsin; Tekin, Bayram
2010-08-01
We present a three-dimensional gravitational Born-Infeld theory which reduces to the recently found new massive gravity (NMG) at the quadratic level in the small curvature expansion and at the cubic order reproduces the deformation of NMG obtained from AdS/CFT. Our action provides a remarkable extension of NMG to all orders in the curvature and might define a consistent quantum gravity.
Remarks on the Tunneling Behavior of Scalar Particles Across Einsein-Born-Infeld Black Holes
NASA Astrophysics Data System (ADS)
Tang, Jian; Wu, JingHe
2016-04-01
Motived by the recent work, we discuss the tunneling radiation of the scalar particle from the Einsein-Born-Infeld black hole. The self-gravitional interaction is taken into account in this paper. The result shows that the tunneling rate is related to the exponential of the change of Bekenstein-Hawking entropy and the corrected emission spectrum deviates from the thermnal one. The unitary theory is satisfied.
New Born-Infeld and Dp-brane actions under 2-metric and 3-metric prescriptions
Miao Yangang
2007-04-15
The parent action method is utilized to the Born-Infeld and Dp-brane theories. Various new forms of Born-Infeld and Dp-brane actions are derived by using this systematic approach, in which both the already known 2-metric and newly proposed 3-metric prescriptions are considered. An auxiliary worldvolume tensor field, denoted by {omega}{sub {mu}}{sub {nu}}, is introduced and treated probably as an additional worldvolume metric because it plays a similar role to that of the auxiliary worldvolume (also called intrinsic) metric {gamma}{sub {mu}}{sub {nu}}. Some properties, such as duality, permutation and Weyl invariance as a local worldvolume symmetry of the new forms are analyzed. In particular, a new symmetry, i.e. the double Weyl invariance is discovered in 3-metric forms.
Mass inflation in Eddington-inspired Born-Infeld black holes: Analytical scaling solutions
NASA Astrophysics Data System (ADS)
Avelino, P. P.
2016-05-01
We study the inner dynamics of accreting Eddington-inspired Born-Infeld black holes using the homogeneous approximation and taking charge as a surrogate for angular momentum. We show that there is a minimum of the accretion rate below which mass inflation does not occur, and we derive an analytical expression for this threshold as a function of the fundamental scale of the theory, the accretion rate, the mass, and the charge of the black hole. Our result explicitly demonstrates that, no matter how close Eddington-inspired Born-Infeld gravity is to general relativity, there is always a minimum accretion rate below which there is no mass inflation. For larger accretion rates, mass inflation takes place inside the black hole as in general relativity until the extremely rapid density variations bring it to an abrupt end. We derive analytical scaling solutions for the value of the energy density and of the Misner-Sharp mass attained at the end of mass inflation as a function of the fundamental scale of the theory, the accretion rate, the mass, and the charge of the black hole, and compare these with the corresponding numerical solutions. We find that, except for unreasonably high accretion rates, our analytical results appear to provide an accurate description of homogeneous mass inflation inside accreting Eddington-inspired Born-Infeld black holes.
Primordial brusque bounce in Born-Infeld determinantal gravity
NASA Astrophysics Data System (ADS)
Fiorini, Franco
2016-07-01
We study a particular exact solution to the Born-Infeld determinantal gravity consisting of a cosmological model which undergoes a "brusque bounce." The latter consists of an event characterized by a non-null (but finite) value of the squared Hubble rate H2 occurring at a minimum (non-null) scale factor. The energy density and pressure of the fluid covering the whole manifold are perfectly well behaved in such an event, but the curvature invariants turn out to be undefined there because of the undefined character of H ˙. It is shown that the spacetime that results is geodesically complete and singularity free, and that it corresponds to a picture of an eternal Universe in which a (somewhat unconventional) bounce replaces the standard big bang singularity. This example tends to asize that, beyond Einstein's theory of general relativity, and in the context of extended theories of gravity formulated by purely torsional means, the criterion of a singularity based on pathologies of scalars constructed upon the Riemann curvature tensor becomes objectionable.
Lorentzian wormholes in Eddington-inspired Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Shaikh, Rajibul
2015-07-01
We show that it is possible to construct a wide class of Lorentzian wormholes in Eddington-inspired Born-Infeld gravity with a stress energy which does not violate the weak or null energy condition. The wormholes exist in a certain region of the parameter space. In fact, it is shown that there is a critical value of a parameter defined in our work, below which we have wormholes. Above the critical value, we have a regular black hole spacetime. We put a restriction on the equation of state parameter α (pθ=α ρ ) to have wormholes. We also put a lower limit on both the theory parameter |κ | and the throat radius, to restrict the tidal acceleration (at the throat) below one Earth gravity. As a special case of our general solution, we retrieve the wormhole supported by an electric field for a charge-to-mass ratio greater than the critical value (Q/M) c≈1.144 .
Singular inflation from Born-Infeld-f(R) gravity
NASA Astrophysics Data System (ADS)
Elizalde, Emilio; Makarenko, Andrey N.
2016-07-01
Accelerating dynamics from Born-Infeld-f(R) gravity are studied in a simplified conformal approach without matter. Explicit unification of inflation with late-time acceleration is realized within this singular inflation approach, which is similar to Odintsov-Oikonomou singular f(R) inflation. Our model turns out to be consistent with the latest release of Planck data.
On the flat spacetime Galileons and the Born-Infeld type structures
NASA Astrophysics Data System (ADS)
Campuzano, Cuauhtemoc; Cordero, Rubén; Cruz, Miguel; Rojas, Efraín
2015-04-01
We show how the flat spacetime Galileon field theories (FSGFT) in arbitrary dimensions can be obtained through a Born-Infeld (BI) type structure. This construction involves a brane metric and nonlinear combinations of derivatives of a scalar field. Our setup gives rise to some Galileon tensors and vectors useful for the variational analysis which are related to the momentum density of the probe Lovelock branes floating in a N-dimensional flat bulk. We find further that the Noether currents associated to these Galileon theories may be written in terms of such tensors.
Coulomb field scattering in Born-Infeld electrodynamics
Tennant, Daniel
2011-02-15
In the context of Born-Infeld electrodynamics, the electromagnetic fields interact with each other via their nonlinear couplings. A calculation will be performed where an incoming electromagnetic plane wave scatters off a Coulomb field in the geometrical optics approximation. In addition to finding the first-order angle of deflection, exact solutions for the trajectory will also be found. The possibility of electromagnetic bound states will be discussed.
Critical behavior of Born-Infeld dilaton black holes
NASA Astrophysics Data System (ADS)
Dehghani, M. H.; Sheykhi, A.; Dayyani, Z.
2016-01-01
We explore the critical behavior of (n +1 )-dimensional topological Born-Infeld-dilaton black holes in an extended phase space. We treat the cosmological constant and the Born-Infeld (BI) parameter as the thermodynamic pressure and BI vacuum polarization which can vary. We obtain thermodynamic quantities of the system such as pressure, temperature, Gibbs free energy, and investigate the behavior of these quantities. We also study the analogy of the van der Waals liquid-gas system with the Born-Infeld-dilaton black holes in canonical ensemble in which we can treat the black hole charge as a fixed external parameter. Moreover, we show that the critical values of pressure, temperature and volume are physical provided the coupling constant of dilaton gravity is less than 1 and the horizon is sphere. Finally, we calculate the critical exponents and show that although thermodynamic quantities depend on the dilaton coupling constant, BI parameter and the dimension of the spacetime, they are universal and are independent of metric parameters.
Magnetic branes in third order Lovelock-Born-Infeld gravity
Dehghani, M. H.; Bostani, N.; Hendi, S. H.
2008-09-15
Considering both the nonlinear invariant terms constructed by the electromagnetic field and the Riemann tensor in gravity action, we obtain a new class of (n+1)-dimensional magnetic brane solutions in third order Lovelock-Born-Infeld gravity. This class of solutions yields a spacetime with a longitudinal nonlinear magnetic field generated by a static source. These solutions have no curvature singularity and no horizons but have a conic geometry with a deficit angle {delta}. We find that, as the Born-Infeld parameter decreases, which is a measure of the increase of the nonlinearity of the electromagnetic field, the deficit angle increases. We generalize this class of solutions to the case of spinning magnetic solutions and find that, when one or more rotation parameters are nonzero, the brane has a net electric charge which is proportional to the magnitude of the rotation parameters. Finally, we use the counterterm method in third order Lovelock gravity and compute the conserved quantities of these spacetimes. We found that the conserved quantities do not depend on the Born-Infeld parameter, which is evident from the fact that the effects of the nonlinearity of the electromagnetic fields on the boundary at infinity are wiped away. We also find that the properties of our solution, such as deficit angle, are independent of Lovelock coefficients.
Shock wave polarizations and optical metrics in the Born and the Born-Infeld electrodynamics
NASA Astrophysics Data System (ADS)
Minz, Christoph; von Borzeszkowski, Horst-Heino; Chrobok, Thoralf; Schellstede, Gerold
2016-01-01
We analyze the behavior of shock waves in nonlinear theories of electrodynamics. For this, by use of generalized Hadamard step functions of increasing order, the electromagnetic potential is developed in a series expansion near the shock wave front. This brings about a corresponding expansion of the respective electromagnetic field equations which allows for deriving relations that determine the jump coefficients in the expansion series of the potential. We compute the components of a suitable gauge-normalized version of the jump coefficients given for a prescribed tetrad compatible with the shock front foliation. The solution of the first-order jump relations shows that, in contrast to linear Maxwell's electrodynamics, in general the propagation of shock waves in nonlinear theories is governed by optical metrics and polarization conditions describing the propagation of two differently polarized waves (leading to a possible appearance of birefringence). In detail, shock waves are analyzed in the Born and Born-Infeld theories verifying that the Born-Infeld model exhibits no birefringence and the Born model does. The obtained results are compared to those ones found in literature. New results for the polarization of the two different waves are derived for Born-type electrodynamics.
Modified Eddington-inspired-Born-Infeld Gravity with a Trace Term
NASA Astrophysics Data System (ADS)
Chen, Che-Yu; Bouhmadi-López, Mariam; Chen, Pisin
2016-01-01
In this paper, a modified Eddington-inspired-Born-Infeld (EiBI) theory with a pure trace term g_{μ ν }R being added to the determinantal action is analysed from a cosmological point of view. It corresponds to the most general action constructed from a rank two tensor that contains up to first order terms in curvature. This term can equally be seen as a conformal factor multiplying the metric g_{μ ν }. This very interesting type of amendment has not been considered within the Palatini formalism despite the large amount of works on the Born-Infeld-inspired theory of gravity. This model can provide smooth bouncing solutions which were not allowed in the EiBI model for the same EiBI coupling. Most interestingly, for a radiation filled universe there are some regions of the parameter space that can naturally lead to a de Sitter inflationary stage without the need of any exotic matter field. Finally, in this model we discover a new type of cosmic "quasi-sudden" singularity, where the cosmic time derivative of the Hubble rate becomes very large but finite at a finite cosmic time.
Modified Eddington-inspired-Born-Infeld gravity with a trace term
Chen, Che -Yu; Bouhmadi-Lopez, Mariam; Chen, Pisin
2016-01-22
In this study, a modified Eddington-inspired-Born-Infeld (EiBI) theory with a pure trace term gμνR being added to the determinantal action is analysed from a cosmological point of view. It corresponds to the most general action constructed from a rank two tensor that contains up to first order terms in curvature. This term can equally be seen as a conformal factor multiplying the metric gμν . This very interesting type of amendment has not been considered within the Palatini formalism despite the large amount of works on the Born-Infeld-inspired theory of gravity. This model can provide smooth bouncing solutions which weremore » not allowed in the EiBI model for the same EiBI coupling. Most interestingly, for a radiation filled universe there are some regions of the parameter space that can naturally lead to a de Sitter inflationary stage without the need of any exotic matter field. Finally, in this model we discover a new type of cosmic “quasi-sudden” singularity, where the cosmic time derivative of the Hubble rate becomes very large but finite at a finite cosmic time.« less
Horizon structure and shadow of rotating Einstein-Born-Infeld black holes
NASA Astrophysics Data System (ADS)
Atamurotov, Farruh
2016-07-01
We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the Born-Infeld parameter goes to innity ( ! 1). We nd that for a given , mass M and charge Q, there exist critical spinning parameter aE and rEH, which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and aE decreases and rEH increases with increase in the Born-Infeld parameter . While a < aE describe a non-extremal Einstein-Born- Infeld black hole with outer and inner horizons. Similarly, the effect of on innite redshift surface and in turn on ergoregion is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational eld. We also investigate the shadow cast by the rotating Einstein- Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated that allows us to investigate the shadow cast by a black hole which is found to be a dark zone covered by a circle. Interestingly, the shadows of Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole which are concentric circles, for different values of the Born-Infeld parameter , whose radius decreases with increase in the value of parameter . The shadows for the rotating Einstein-Born-Infeld solution are also included.
Spectral indices in Eddington-inspired Born-Infeld inflation
NASA Astrophysics Data System (ADS)
Cho, Inyong; Gong, Jinn-Ouk
2015-09-01
We investigate the scalar and tensor spectral indices of the quadratic inflation model in Eddington-inspired Born-Infeld (EiBI) gravity. We find that the EiBI corrections to the spectral indices are of second and first order in the slow-roll approximation for the scalar and tensor perturbations, respectively. This is very promising since the quadratic inflation model in general relativity provides a very nice fit for the spectral indices. Together with the suppression of the tensor-to-scalar ratio, EiBI inflation is agrees well with the observational data.
Energy decomposition within Einstein-Born-Infeld black holes
NASA Astrophysics Data System (ADS)
Pereira, Jonas P.; Rueda, Jorge A.
2015-03-01
We analyze the consequences of the recently found generalization of the Christodoulou-Ruffini black hole mass decomposition for Einstein-Born-Infeld black holes [characterized by the parameters (Q ,M ,b ), where M =M (Mirr,Q ,b ) , b scale field, Q charge, Mirr "irreducible mass," physically meaning the energy of a black hole when its charge is null] and their interactions. We show in this context that their description is largely simplified and can basically be split into two families depending upon the parameter b |Q |. If b |Q |≤1 /2 , then black holes could have even zero irreducible masses and they always exhibit single nondegenerated horizons. If b |Q |>1 /2 , then an associated black hole must have a minimum irreducible mass (related to its minimum energy) and has two horizons up to a transitional irreducible mass. For larger irreducible masses, single horizon structures raise again. By assuming that black holes emit thermal uncharged scalar particles, we further show in light of the black hole mass decomposition that one satisfying b |Q |>1 /2 takes an infinite amount of time to reach the zero temperature, settling down exactly at its minimum energy. Finally, we argue that depending on the fundamental parameter b , the radiation (electromagnetic and gravitational) coming from Einstein-Born-Infeld black holes could differ significantly from Einstein-Maxwell ones. Hence, it could be used to assess such a parameter.
Dirac-Born-Infeld inflation model with kinetic coupling to Einstein gravity
NASA Astrophysics Data System (ADS)
Qiu, Taotao
2016-06-01
In this paper, we study a new class of inflation models which generalize the Dirac-Born-Infeld (DBI) action with the addition of a nonminimal kinetic coupling (NKC) term. We dub this model as the new DBI inflation model. The NKC term does not bring a new dynamical degree of freedom, so the equations of motion remain of second order. However, with such coupling, the action is no longer linear with respect to the Einstein curvature term (R or Gμ ν), which leads to a correction term of k4 in the perturbations. The new DBI inflation model can be viewed as a theory beyond Horndeski. Without violating approximate scale invariance, such correction may lead to new effects on the inflationary spectra that can be tested by future observations.
Horizon structure of rotating Einstein-Born-Infeld black holes and shadow
NASA Astrophysics Data System (ADS)
Atamurotov, Farruh; Ghosh, Sushant G.; Ahmedov, Bobomurat
2016-05-01
We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the Born-Infeld parameter goes to infinity (β → ∞). We find that for a given β , mass M, and charge Q, there exist a critical spinning parameter aE and rHE, which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and aE decreases and rHE increases with increase of the Born-Infeld parameter β , while a
Horizon structure and shadow of rotating Einstein-Born-Infeld black holes
NASA Astrophysics Data System (ADS)
Atamurotov, Farruh
2016-07-01
We investigate the horizon structure of the rotating Einstein-Born-Infeld solution which goes over to the Einstein-Maxwell's Kerr-Newman solution as the Born-Infeld parameter goes to innity ( ! 1). We nd that for a given , mass M and charge Q, there exist critical spinning parameter aE and rEH, which corresponds to an extremal Einstein-Born-Infeld black hole with degenerate horizons, and aE decreases and rEH increases with increase in the Born-Infeld parameter . While a < aE describe a non-extremal Einstein-Born- Infeld black hole with outer and inner horizons. Similarly, the e ect of on innite redshift surface and in turn on ergoregion is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational eld. We also investigate the shadow cast by the rotating Einstein- Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated that allows us to investigate the shadow cast by a black hole which is found to be a dark zone covered by a circle. Interestingly, the shadows of Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole which are concentric circles, for di erent values of the Born-Infeld parameter , whose radius decreases with increase in the value of parameter . The shadows for the rotating Einstein-Born-Infeld solution are also included.
Classical and quantum cosmology of Born-Infeld type models
NASA Astrophysics Data System (ADS)
Kamenshchik, Alexander; Kiefer, Claus; Kwidzinski, Nick
2016-04-01
We discuss Born-Infeld type fields (tachyon fields) in classical and quantum cosmology. We first partly review and partly extend the discussion of the classical solutions and focus in particular on the occurrence of singularities. For quantization, we employ geometrodynamics. In the case of constant potential, we discuss both Wheeler-DeWitt quantization and reduced quantization. We are able to give various solutions and discuss their asymptotics. For the case of general potential, we transform the Wheeler-DeWitt equation to a form where it leads to a difference equation. Such a difference equation was previously found in the quantization of black holes. We give explicit results for the cases of constant potential and inverse squared potential and point out special features possessed by solutions of the difference equation.
The virial theorem in Eddington-Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Santos, Noelia S.; Santos, Janilo
2015-12-01
We consider the possibility that the Eddington-Born-Infeld (EBI) modified gravity provides an alternative explanation for the mass discrepancy in clusters of galaxies. For this purpose we derive the modified Einstein field equations, finding an additional "geometrical mass" term which provides an effective contribution to the gravitational binding energy. Using some approximations and assumptions for weak gravitational fields, and taking into account the collisionless relativistic Boltzmann equation, we derive a generalized version of the virial theorem in the framework of EBI gravity. We show that the "geometrical mass" term may account for the well known virial mass discrepancy in clusters of galaxies. We also derive the velocity dispersion relation for galaxies in the clusters, which could provide an efficient method for testing EBI gravity from astrophysical observations.
Holographic superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics
Jing Jiliang; Wang Liancheng; Pan Qiyuan; Chen Songbai
2011-03-15
We investigate the holographic superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics. We find that the Gauss-Bonnet constant, the model parameters, and the Born-Infeld coupling parameter will affect the formation of the scalar hair, the transition point of the phase transition from the second order to the first order, and the relation connecting the gap frequency in conductivity with the critical temperature. The combination of Gauss-Bonnet gravity and the Born-Infeld electrodynamics provides richer physics in the phase transition and the condensation of the scalar hair.
Avelino, P.P.
2012-11-01
In this paper we investigate the classical non-relativistic limit of the Eddington-inspired Born-Infeld theory of gravity. We show that strong bounds on the value of the only additional parameter of the theory κ, with respect to general relativity, may be obtained by requiring that gravity plays a subdominant role compared to electromagnetic interactions inside atomic nuclei. We also discuss the validity of the continuous fluid approximation used in this and other astrophysical and cosmological studies. We argue that although the continuous fluid approximation is expected to be valid in the case of sufficiently smooth density distributions, its use should eventually be validated at a quantum level.
Holographic paramagnetism-ferromagnetism phase transition in the Born-Infeld electrodynamics
NASA Astrophysics Data System (ADS)
Wu, Ya-Bo; Zhang, Cheng-Yuan; Lu, Jun-Wang; Fan, Bi; Shu, Shuang; Liu, Yu-Chen
2016-09-01
In the probe limit, we investigate the effects of the Born-Infeld electrodynamics on the holographic paramagnetism-ferromagnetism phase transition in the background of a Schwarzschild-AdS black hole spacetime. We find that the presence of Born-Infeld scale parameter b decreases the critical temperature and makes the magnetic moment harder to form in the case of without external field. Furthermore, the increase of b will result in extending the period of the external magnetic field.
Aiello, Matias; Bengochea, Gabriel R; Ferraro, Rafael E-mail: gabriel@iafe.uba.ar
2008-06-15
Born-Infeld electromagnetic waves interacting with a static magnetic background in an expanding universe are studied. The non-linear character of Born-Infeld electrodynamics modifies the relation between the energy flux and the distance to the source, which gains a new dependence on the redshift that is governed by the background field. We compute the luminosity distance as a function of the redshift and compare with Maxwellian curves for supernovae type Ia.
Topological black holes in Lovelock-Born-Infeld gravity
Dehghani, M. H.; Alinejadi, N.; Hendi, S. H.
2008-05-15
In this paper, we present topological black holes of third order Lovelock gravity in the presence of cosmological constant and nonlinear electromagnetic Born-Infeld field. Depending on the metric parameters, these solutions may be interpreted as black hole solutions with inner and outer event horizons, an extreme black hole or naked singularity. We investigate the thermodynamics of asymptotically flat solutions and show that the thermodynamic and conserved quantities of these black holes satisfy the first law of thermodynamic. We also endow the Ricci flat solutions with a global rotation and calculate the finite action and conserved quantities of these class of solutions by using the counterterm method. We compute the entropy through the use of the Gibbs-Duhem relation and find that the entropy obeys the area law. We obtain a Smarr-type formula for the mass as a function of the entropy, the angular momenta, and the charge, and compute temperature, angular velocities, and electric potential and show that these thermodynamic quantities coincide with their values which are computed through the use of geometry. Finally, we perform a stability analysis for this class of solutions in both the canonical and the grand-canonical ensemble and show that the presence of a nonlinear electromagnetic field and higher curvature terms has no effect on the stability of the black branes, and they are stable in the whole phase space.
Eddington-inspired Born-Infeld gravity: Phenomenology of nonlinear gravity-matter coupling
NASA Astrophysics Data System (ADS)
Pani, Paolo; Delsate, Térence; Cardoso, Vitor
2012-04-01
Viable corrections to the matter sector of Poisson’s equation may result in qualitatively different astrophysical phenomenology, for example, the gravitational collapse and the properties of compact objects can change drastically. We discuss a class of modified nonrelativistic theories and focus on a relativistic completion, Eddington-inspired Born-Infeld gravity. This recently proposed theory is equivalent to General Relativity in vacuum, but its nontrivial coupling to matter prevents singularities in early cosmology and in the nonrelativistic collapse of noninteracting particles. We extend our previous analysis, discussing further developments. We present a full numerical study of spherically symmetric nonrelativistic gravitational collapse of dust. For any positive coupling, the final state of the collapse is a regular pressureless star rather than a singularity. We also argue that there is no Chandrasekhar limit for the mass of a nonrelativistic white dwarf in this theory. Finally, we extend our previous results in the fully relativistic theory by constructing static and slowly rotating compact stars governed by nuclear-physics inspired equations of state. In the relativistic theory, there exists an upper bound on the mass of compact objects, suggesting that black holes can still be formed in the relativistic collapse.
Primordial power spectra of Eddington-inspired Born-Infeld inflation in strong gravity limit
NASA Astrophysics Data System (ADS)
Cho, Inyong; Singh, Naveen K.
2015-07-01
We investigate the scalar and the tensor perturbations of the φ2 inflation model in the strong-gravity limit of Eddington-inspired Born-Infeld (EiBI) theory. In order to consider the strong EiBI-gravity effect, we take the value of κ large, where κ is the EiBI theory parameter. The energy density of the Universe at the early stage is very high, and the Universe is in a strong-gravity regime. Therefore, the perturbation feature is not altered from what was investigated earlier. At the attractor inflationary stage, however, the feature is changed in the strong EiBI-gravity limit. The correction to the scalar perturbation in this limit comes mainly via the background matter field, while that to the tensor perturbation comes directly from the gravity (κ ) effect. The change in the value of the scalar spectrum is little compared with that in the weak EiBI-gravity limit, or in general relativity. The form of the tensor spectrum is the same as that in the weak limit, but the value of the spectrum can be suppressed down to zero in the strong limit. Therefore, the resulting tensor-to-scalar ratio can also be suppressed in the same way, which makes the φ2 model in EiBI theory viable.
Magnetized relativistic stellar models in Eddington-inspired Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Sotani, Hajime
2015-04-01
We consider the structure of the magnetic fields inside the neutron stars in Eddington-inspired Born-Infeld (EiBI) gravity. In order to construct the magnetic fields, we derive the relativistic Grad-Shafranov equation in EiBI and numerically determine the magnetic distribution in such a way that the interior magnetic fields should be connected to the exterior distribution. Then, we find that the magnetic distribution inside the neutron stars in EiBI is qualitatively similar to that in general relativity, where the deviation of magnetic distribution in EiBI from that in general relativity is almost comparable to uncertainty due to the equation of state for the neutron star matter. However, we also find that the magnetic fields in the crust region are almost independent of the coupling constant in EiBI, which suggests a possibility of obtaining the information about the crust equation of state independent from the gravitational theory via the observations of the phenomena associated with the crust region. In any case, since the imprint of EiBI gravity on the magnetic fields is weak, the magnetic fields could be a poor probe of gravitational theories, considering the many magnetic uncertainties.
On the generalized wormhole in the Eddington-inspired Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Tamang, Amarjit; Potapov, Alexander A.; Lukmanova, Regina; Izmailov, Ramil; Nandi, Kamal K.
2015-12-01
In this paper, we wish to investigate certain observable effects in the recently obtained wormhole solution of the Eddington-inspired Born-Infeld (EiBI) theory, which generalizes the zero-mass Ellis-Bronnikov wormhole of general relativity. The solutions of EiBI theory contain an extra parameter κ having the inverse dimension of the cosmological constant Λ, and which is expected to modify various general relativistic observables such as the masses of wormhole mouths, tidal forces and light deflection. A remarkable result is that a non-zero κ could prevent the tidal forces in the geodesic orthonormal frame from becoming arbitrarily large near a small throat radius ({r}0˜ 0) contrary to what happens near a small Schwarzschild horizon radius (M˜ 0). The role of κ in the flare-out and energy conditions is also analyzed, which reveals that the energy conditions are violated. We show that the exotic matter in the EiBI wormhole cannot be interpreted as a phantom (ω =\\frac{{p}{{r}}}{ρ }\\lt -1) or ghost field ϕ of general relativity due to the fact that both ρ and p r are negative for all κ.
Resonances of Spin-1/2 Fermions in Eddington-Inspired Born-Infeld Gravity
NASA Astrophysics Data System (ADS)
Fu, Qi-Ming; Zhao, Li; Du, Yun-Zhi; Gu, Bao-Min
2016-03-01
We investigate the fermionic resonances for both chiralities in five-dimensional Eddington-inspired Born-Infeld (EiBI) theory. In order to localize fermion on the brane, it needs to be considered the Yukawa coupling between the fermion and the background scalar field. In our models, since the background scalar field has kink, double kink, or anti-kink solution, the system has rich resonant Kaluza–Klein (KK) modes structure. The massive KK fermionic modes feel a volcano potential, which result in a fermionic zero mode and a set of continuous massive KK modes. The inner structure of the branes and a free parameter in background scalar field influence the resonant behaviors of the massive KK fermions. Supported in part by the National Natural Science Foundation of China under Grant No. 11075065, the Huo Ying-Dong Education Foundation of Chinese Ministry of Education under Grant No. 121106 and the Fundamental Research Funds for the Central Universities under Grant No. lzujbky-2014-31
Inner structure of black holes in Eddington-inspired Born-Infeld gravity: The role of mass inflation
NASA Astrophysics Data System (ADS)
Avelino, P. P.
2016-02-01
We investigate the interior dynamics of accreting black holes in Eddington-inspired Born-Infeld gravity using the homogeneous approximation and taking charge as a surrogate for angular momentum, showing that accretion can have an enormous impact on their inner structure. We find that, unlike in general relativity, there is a minimum accretion rate below which the mass inflation instability, which drives the center-of-mass streaming density to exponentially high values in an extremely short interval of time, does not occur. We further show that, above this threshold, mass inflation takes place inside black holes much in the same way as in general relativity, but is brought to a halt at an energy density which is, in general, much smaller than the fundamental energy density of the theory. We conjecture that some of these results may be a common feature of modified gravity theories in which significant deviations from general relativity manifest themselves at high densities.
NASA Astrophysics Data System (ADS)
Sotani, Hajime; Miyamoto, Umpei
2015-08-01
We systematically examine the properties of null geodesics around an electrically charged, asymptotically flat black hole in Eddington-inspired Born-Infeld gravity, varying the electric charge of the black hole and the coupling constant in the theory. We find that the radius of the unstable circular orbit for a massless particle decreases with the coupling constant, if the value of the electrical charge is fixed. Additionally, we consider the strong gravitational lensing around such a black hole. We show that the deflection angle, the position angle of the relativistic images, and the magnification due to the light bending in strong gravitational field are quite sensitive to the parameters determining the black hole solution. Thus, through the accurate observations associated with the strong gravitational lensing, it might be possible to reveal the gravitational theory in a strong field regime.
Palatini-Born-Infeld gravity, bouncing universe, and black hole formation
NASA Astrophysics Data System (ADS)
Komada, Meguru; Nojiri, Shin'ichi; Katsuragawa, Taishi
2016-04-01
We consider the Palatini formalism of the Born-Infeld gravity. In the Palatini formalism, the propagating mode is only graviton, whose situation is different from that in the metric formalism. We discuss the FRW cosmology by using an effective potential. Especially we consider the condition that the bouncing could occur. We also give some speculations about the black hole formation
Thermodynamics of Einstein-Born-Infeld black holes in three dimensions
Myung, Yun Soo; Kim, Yong-Wan; Park, Young-Jai
2008-08-15
We show that all thermodynamic quantities of the Einstein-Born-Infeld black holes in three dimensions can be obtained from the dilaton and its potential of two-dimensional dilaton gravity through dimensional reduction. These are all between nonrotating uncharged BTZ (Banados-Teitelboim-Zanelli) black hole (NBTZ) and charged BTZ black hole (CBTZ)
Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-Infeld
Jiménez, Jose Beltrán; Heisenberg, Lavinia; Olmo, Gonzalo J. E-mail: Lavinia.Heisenberg@unige.ch
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.
An extended magnetostatic Born-Infeld model with a concave lower order term
Chen, Jun; Pan, Xing-Bin
2013-11-15
This paper concerns an extended Born-Infeld model with a concave lower order term for the magnetostatic case. Three types of boundary value problems are considered: the boundary condition prescribing the tangential component of A, the natural boundary condition, and the boundary condition prescribing the tangential component of curl A. In each case we obtain existence and regularity of solutions for small boundary data.
Massive vector multiplet inflation with Dirac-Born-Infeld type action
NASA Astrophysics Data System (ADS)
Abe, Hiroyuki; Sakamura, Yutaka; Yamada, Yusuke
2015-06-01
We investigate the inflation model with a massive vector multiplet in a case that the action of the vector multiplet is extended to the Dirac-Born-Infeld (DBI) type one. We show the massive DBI action in four-dimensional N =1 supergravity and find that the higher-order corrections associated with the DBI extension make the scalar potential flat with a simple choice of the matter couplings. We also discuss the DBI extension of the new minimal Starobinsky model and find that it is dual to a special class of the massive DBI action.
Ehrenfest's scheme and thermodynamic geometry in Born-Infeld AdS black holes
NASA Astrophysics Data System (ADS)
Lala, Arindam; Roychowdhury, Dibakar
2012-10-01
In this paper, we analyze the phase transition phenomena in Born-Infeld anti-de Sitter (BI AdS) black holes using Ehrenfest’s scheme of standard thermodynamics. The critical points are marked by the divergences in the heat capacity. In order to investigate the nature of the phase transition, we analytically check both Ehrenfest equations near the critical points. Our analysis reveals that this is indeed a second order phase transition. Finally, we analyze the nature of the phase transition using the state space geometry approach. This is found to be compatible with Ehrenfest’s scheme.
The nonlinear stability of the trivial solution to the Maxwell-Born-Infeld system
NASA Astrophysics Data System (ADS)
Speck, Jared
2012-08-01
In this article, we use an electromagnetic gauge-free framework to establish the existence of small-data global solutions to the Maxwell-Born-Infeld (MBI) system on the Minkowski spacetime background in 1+3 dimensions. Because the nonlinearities in the system have a special null structure, we are also able to show that these solutions decay at least as fast as solutions to the linear Maxwell-Maxwell system. In addition, we show that on any Lorentzian manifold, the MBI system is hyperbolic in the interior of the field-strength regime in which its Lagrangian is real-valued.
Dark energy as a Born-Infeld gauge interaction violating the equivalence principle.
Füzfa, A; Alimi, J-M
2006-08-11
We investigate the possibility that dark energy does not couple to gravitation in the same way as ordinary matter, yielding a violation of the weak and strong equivalence principles on cosmological scales. We build a transient mechanism in which gravitation is pushed away from general relativity by a Born-Infeld gauge interaction acting as an abnormally weighting (dark) energy. This mechanism accounts for the Hubble diagram of far-away supernovae by cosmic acceleration and time variation of the gravitational constant while accounting naturally for the present tests on general relativity. PMID:17026155
c-functions in the Born-Infeld extended new massive gravity
Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram
2010-07-15
We derive and study the equations of motion of the Born-Infeld extension of new massive gravity for globally and asymptotically (anti-)de Sitter spaces, and show that the assumptions of the null-energy condition and holography (that bounds the c-function) lead to two simple c-functions, one of which is equivalent to the c-function of Einstein's gravity. We also show that, at the fixed point, the c-function gives the central charge of the Virasoro algebra and the coefficient of the Weyl anomaly up to a constant.
Notes on Born-Infeld-like modified gravity
NASA Astrophysics Data System (ADS)
Kruglov, S. I.
2016-02-01
We investigate the modified F(R) gravity theory with the function F(R) = (1-√{1-2λ R-σ(λ R)2})/λ. The action is converted into Einstein-Hilbert action at small values of λ and σ. The local tests give a bound on the parameters, λ(1+σ)≤2×10^{-6} cm2. The Jordan and Einstein frames are considered, the potential, and the mass of the scalar field were obtained. The constant curvature solutions of the model are found. It was demonstrated that the de Sitter space is unstable but a solution with zero Ricci scalar is stable. The cosmological parameters of the model are evaluated. Critical points of autonomous equations are obtained and described.
Thermodynamics of rotating black branes in (n+1)-dimensional Einstein-Born-Infeld gravity
Dehghani, M. H.; Sedehi, H. R. Rastegar
2006-12-15
We construct a new class of charged rotating solutions of (n+1)-dimensional Einstein-Born-Infeld gravity with cylindrical or toroidal horizons in the presence of cosmological constant and investigate their properties. These solutions are asymptotically (anti)-de Sitter and reduce to the solutions of Einstein-Maxwell gravity as the Born-Infeld parameters goes to infinity. We find that these solutions can represent black branes, with inner and outer event horizons, an extreme black brane or a naked singularity provided the parameters of the solutions are chosen suitably. We compute temperature, mass, angular momentum, entropy, charge and electric potential of the black brane solutions. We obtain a Smarr-type formula and show that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis by computing the heat capacity and the determinant of Hessian matrix of mass of the system with infinite boundary with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles, and show that the system is thermally stable in the whole phase space. Also, we find that there exists an unstable phase when the finite size effect is taken into account.
Thermodynamics of black holes in (n+1)-dimensional Einstein-Born-Infeld-dilaton gravity
Sheykhi, A.; Riazi, N.
2007-01-15
We construct a new class of (n+1)-dimensional (n{>=}3) black hole solutions in Einstein-Born-Infeld-dilaton gravity with Liouville-type potential for the dilaton field and investigate their properties. These solutions are neither asymptotically flat nor (anti)-de Sitter. We find that these solutions can represent black holes, with inner and outer event horizons, an extreme black hole, or a naked singularity provided the parameters of the solutions are chosen suitably. We compute the thermodynamic quantities of the black hole solutions and find that these quantities satisfy the first law of thermodynamics. We also perform a stability analysis and investigate the effect of dilaton on the stability of the solutions.
Origin of the universe: A hint from Eddington-inspired Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Kim, Hyeong-Chan
2014-09-01
We study the `initial state' of an anisotropic universe in Eddington-inspired Born-Infeld gravity filled with a scalar field, whose potential has various forms. With this purpose, the evolution of a spatially-flat, homogeneous, anisotropic Kasner universe is studied. We find an exact evolution of the universe for each scalar potential by imposing a maximal pressure condition. The solution is shown to describe the initial state of the universe. The state is regular if the scalar potential does not increase faster than the quadratic power for large-field values. We also show that the anisotropy does not raise any defect in the early universe, contrary to the case of general relativity.
Holographic fermionic spectrum from Born-Infeld AdS black hole
NASA Astrophysics Data System (ADS)
Wu, Jian-Pin
2016-07-01
In this letter, we systematically explore the holographic (non-)relativistic fermionic spectrum without/with dipole coupling dual to Born-Infeld anti-de Sitter (BI-AdS) black hole. For the relativistic fermionic fixed point, this holographic fermionic system exhibits non-Fermi liquid behavior. Also, with the increase of BI parameter γ, the non-Fermi liquid becomes even "more non-Fermi". When the dipole coupling term is included, we find that the BI term makes it a lot tougher to form the gap. While for the non-relativistic fermionic system with large dipole coupling in BI-AdS background, with the increase of BI parameter, the gap comes into being again.
Formation of caustics in Dirac-Born-Infeld type scalar field systems
Goswami, U. D.; Nandan, H.; Sami, M.
2010-11-15
We investigate the formation of caustics in the Dirac-Born-Infeld type scalar field systems for generic classes of potentials, viz., massive rolling scalar with potential, V({phi})=V{sub 0}e{sup {+-}(1/2)M2{phi}2} and inverse power-law potentials with V({phi})=V{sub 0}/{phi}{sup n}, 0
Asymptotic properties of a supposedly regular (Dirac-Born-Infeld) modification of general relativity
García-Salcedo, Ricardo; Gonzalez, Tame; Napoles, Yunelsy; Leyva, Yoelsy; Moreno, Claudia; Quiros, Israel E-mail: tame@uclv.edu.cu E-mail: yna@uclv.edu.cu E-mail: iquiros@fisica.ugto.mx
2010-02-01
We apply the dynamical systems tools to study the asymptotic properties of a cosmological model based on a non-linear modification of General Relativity in which the standard Einstein-Hilbert action is replaced by one of Dirac-Born-Infeld type. It is shown that the dynamics of this model is extremely rich: there are found equilibrium points in the phase space that can be associated with matter-dominated, matter-curvature scaling, de Sitter, and even phantom-like solutions. Depending on the value of the overall parameters the dynamics in phase space can show multi-attractor structure into the future (multiple future attractors may co-exist). This is a consequence of bifurcations in control parameter space, showing strong dependence of the model's dynamical properties on the free parameters. Contrary to what is expected from non-linear modifications of general relativity of this kind, removal of the initial spacetime singularity is not a generic feature of the corresponding cosmological model. Instead, the starting point of the cosmic dynamics — the past attractor in the phase space — is a state of infinitely large value of the Hubble rate squared, usually associated with the big bang singularity.
Einstein-Born-Infeld-massive gravity: adS-black hole solutions and their thermodynamical properties
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Panah, B. Eslam; Panahiyan, S.
2015-11-01
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, 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.
- criticality of topological black holes in Lovelock-Born-Infeld gravity
NASA Astrophysics Data System (ADS)
Mo, Jie-Xiong; Liu, Wen-Biao
2014-04-01
To understand the effect of third order Lovelock gravity, - criticality of topological AdS black holes in Lovelock-Born-Infeld gravity is investigated. The thermodynamics is further explored with some more extensions and in some more detail than the previous literature. A detailed analysis of the limit case is performed for the seven-dimensional black holes. It is shown that, for the spherical topology, - criticality exists for both the uncharged and the charged cases. Our results demonstrate again that the charge is not the indispensable condition of - criticality. It may be attributed to the effect of higher derivative terms of the curvature because similar phenomenon was also found for Gauss-Bonnet black holes. For , there would be no - criticality. Interesting findings occur in the case , in which positive solutions of critical points are found for both the uncharged and the charged cases. However, the - diagram is quite strange. To check whether these findings are physical, we give the analysis on the non-negative definiteness condition of the entropy. It is shown that, for any nontrivial value of , the entropy is always positive for any specific volume . Since no - criticality exists for in Einstein gravity and Gauss-Bonnet gravity, we can relate our findings with the peculiar property of third order Lovelock gravity. The entropy in third order Lovelock gravity consists of extra terms which are absent in the Gauss-Bonnet black holes, which makes the critical points satisfy the constraint of non-negative definiteness condition of the entropy. We also check the Gibbs free energy graph and "swallow tail" behavior can be observed. Moreover, the effect of nonlinear electrodynamics is also included in our research.
NASA Astrophysics Data System (ADS)
Guo, Xiong-Ying; Zhang, Li-Chun; Zhao, Ren
2014-06-01
We employ the simple analytic method and the variational method of the Strum-Liouville (S-L) eigenvalue problem to analytically study the holographic superconductor phase transition in Gauss-Bonnet gravity with Born-Infeld (BI) electrodynamics in the probe limit, respectively. We find that the scalar hair formation at low temperatures is indeed affected by the Gauss-Bonnet as well as the BI coupling parameters, but also by the scalar field mass and the spacetime dimensional. Our analytic result has been found in agreement with the numerical results.
NASA Astrophysics Data System (ADS)
Accioly, Antonio; Gaete, Patricio; Helaÿel-Neto, José A.
We calculate the lowest-order corrections to the static potential for both the generalized Born-Infeld electrodynamics and an Euler-Heisenberg-like model, in the presence of a constant external magnetic field. Our analysis is carried out within the framework of the gauge-invariant but path-dependent variables formalism. The calculation reveals a long-range correction ((1)/(r5)-type) to the Coulomb potential for the generalized Born-Infeld electrodynamics. Interestingly enough, in the Euler-Heisenberg-like model, the static potential remains Coulombian. Therefore, contrary to popular belief, the quantized truncated action and the truncated quantized action do not commute at all.
NASA Astrophysics Data System (ADS)
Bouhmadi-López, Mariam; Chen, Che-Yu; Chen, Pisin
2015-02-01
The Eddington-inspired-Born-Infeld scenario (EiBI) can prevent the big bang singularity for a matter content whose equation of state is constant and positive. In a recent paper [Bouhmadi-Lopez et al. (Eur. Phys. J. C 74:2802, 2014)] we showed that, on the contrary, it is impossible to smooth a big rip in the EiBI setup. In fact the situations are still different for other singularities. In this paper we show that a big freeze singularity in GR can in some cases be smoothed to a sudden or a type IV singularity under the EiBI scenario. Similarly, a sudden or a type IV singularity in GR can be replaced in some regions of the parameter space by a type IV singularity or a loitering behaviour, respectively, in the EiBI framework. Furthermore, we find that the auxiliary metric related to the physical connection usually has a smoother behaviour than that based on the physical metric. In addition, we show that bound structures close to a big rip or a little rip will be destroyed before the advent of the singularity and will remain bound close to a sudden, big freeze or type IV singularity. We then constrain the model following a cosmographic approach, which is well known to be model independent, for a given Friedmann-Lemaître-Robertson-Walker geometry. It turns out that among the various past or present singularities, the cosmographic analysis can pick up the physical region that determines the occurrence of a type IV singularity or a loitering effect in the past. Moreover, to determine which of the future singularities or doomsdays is more probable, observational constraints on the higher-order cosmographic parameters are required.
NASA Astrophysics Data System (ADS)
Sepehri, Alireza
2016-07-01
Recently, some authors (Cruz and Rojas, 2013 [1]) have constructed a Born-Infeld type action which may be written in terms of the Lovelock brane Lagrangians for a given dimension p. We reconsider their model in M-theory and study the process of birth and growth of nonlinear spinor and bosonic gravity during the construction of Mp-branes. Then, by application of this idea to BIonic system, we construct a BIonic superconductor in the background of nonlinear gravity. In this model, first, M0-branes link to each other and build an M5-brane and an anti-M5-brane connected by an M2-brane. M0-branes are zero dimensional objects that only scalars are attached to them. By constructing higher dimensional branes from M0-branes, gauge fields are produced. Also, if M0-branes don't link to each other completely, the symmetry of system is broken and fermions are created. The curvature produced by fermions has the opposite sign the curvature produced by gauge fields. Fermions on M5-branes and M2 plays the role of bridge between them. By passing time, M2 dissolves in M5's and nonlinear bosonic and spinor gravities are produced. By closing M5-branes towards each other, coupling of two identical fermions on two branes to each other causes that the square mass of their system becomes negative and some tachyonic states are created. For removing these tachyons, M5-branes compact, the sign of gravity between branes reverses, anti-gravity is produced which causes that branes and identical fermions get away from each other. This is the reason for the emergence of Pauli exclusion principle in Bionic system. Also, the spinor gravity vanishes and its energy builds a new M2 between M5-branes. We obtain the resistivity in this system and find that its value decreases by closing M5 branes to each other and shrinks to zero at colliding point of branes. This idea has different applications. For example, in cosmology, universes are located on M5-branes and M2-brane has the role of bridge between
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Dehghani, A.
2015-03-01
In this paper, we obtain topological black hole solutions of third-order Lovelock gravity coupled with two classes of Born-Infeld-type nonlinear electrodynamics with anti-de Sitter asymptotic structure. We investigate geometric and thermodynamics properties of the solutions and obtain conserved quantities of the black holes. We examine the first law of thermodynamics and find that the conserved and thermodynamic quantities of the black hole solutions satisfy the first law of thermodynamics. Finally, we calculate the heat capacity and determinant of the Hessian matrix to evaluate thermal stability in both canonical and grand canonical ensembles. Moreover, we consider the extended phase space thermodynamics to obtain a generalized first law of thermodynamics as well as the extended Smarr formula.
NASA Astrophysics Data System (ADS)
Izmailov, Ramil; Potapov, Alexander A.; Filippov, Alexander I.; Ghosh, Mithun; Nandi, Kamal K.
2015-03-01
We investigate the stability of circular material orbits in the analytic galactic metric recently derived by Harko et al., Mod. Phys. Lett. A29, 1450049 (2014). It turns out that stability depends more strongly on the dark matter central density ρ0 than on other parameters of the solution. This property then yields an upper limit on ρ0 for each individual galaxy, which we call here ρ 0 upper, such that stable circular orbits are possible only when the constraint ρ 0<= ρ 0 upper is satisfied. This is our new result. To approximately quantify the upper limit, we consider as a familiar example our Milky Way galaxy that has a projected dark matter radius RDM 180 kpc and find that ρ 0 upper ˜ 2.37× 1011 M⊙ kpc-3. This limit turns out to be about four orders of magnitude larger than the latest data on central density ρ0 arising from the fit to the Navarro-Frenk-White (NFW) and Burkert density profiles. Such consistency indicates that the Eddington-inspired Born-Infeld (EiBI) solution could qualify as yet another viable alternative model for dark matter.
On-Shell Recursion Relations for Effective Field Theories.
Cheung, Clifford; Kampf, Karol; Novotny, Jiri; Shen, Chia-Hsien; Trnka, Jaroslav
2016-01-29
We derive the first ever on-shell recursion relations applicable to effective field theories. Based solely on factorization and the soft behavior of amplitudes, these recursion relations employ a new rescaling momentum shift to construct all tree-level scattering amplitudes in the nonlinear sigma model, Dirac-Born-Infeld theory, and the Galileon. Our results prove that all theories with enhanced soft behavior are on-shell constructible. PMID:26871321
Eddington's theory of gravity and its progeny.
Bañados, Máximo; Ferreira, Pedro G
2010-07-01
We resurrect Eddington's proposal for the gravitational action in the presence of a cosmological constant and extend it to include matter fields. We show that the Newton-Poisson equation is modified in the presence of sources and that charged black holes show great similarities with those arising in Born-Infeld electrodynamics coupled to gravity. When we consider homogeneous and isotropic space-times, we find that there is a minimum length (and maximum density) at early times, clearly pointing to an alternative theory of the big bang. We thus argue that the modern formulation of Eddington's theory, Born-Infeld gravity, presents us with a novel, nonsingular description of the Universe. PMID:20867432
Fundamental string solutions in open string field theories
Michishita, Yoji
2006-02-15
In Witten's open cubic bosonic string field theory and Berkovits' superstring field theory we investigate solutions of the equations of motion with appropriate source terms, which correspond to Callan-Maldacena solution in Born-Infeld theory representing fundamental strings ending on the D-branes. The solutions are given in order by order manner, and we show some full order properties in the sense of {alpha}{sup '} expansion. In superstring case we show that the solution is 1/2 BPS in full order.
Effective Field Theories from Soft Limits of Scattering Amplitudes.
Cheung, Clifford; Kampf, Karol; Novotny, Jiri; Trnka, Jaroslav
2015-06-01
We derive scalar effective field theories-Lagrangians, symmetries, and all-from on-shell scattering amplitudes constructed purely from Lorentz invariance, factorization, a fixed power counting order in derivatives, and a fixed order at which amplitudes vanish in the soft limit. These constraints leave free parameters in the amplitude which are the coupling constants of well-known theories: Nambu-Goldstone bosons, Dirac-Born-Infeld scalars, and Galilean internal shift symmetries. Moreover, soft limits imply conditions on the Noether current which can then be inverted to derive Lagrangians for each theory. We propose a natural classification of all scalar effective field theories according to two numbers which encode the derivative power counting and soft behavior of the corresponding amplitudes. In those cases where there is no consistent amplitude, the corresponding theory does not exist. PMID:26196613
All bulk and boundary unitary cubic curvature theories in three dimensions
Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram
2011-01-15
We construct all the bulk and boundary unitary cubic curvature parity invariant gravity theories in three dimensions in (anti)-de Sitter spaces. For bulk unitarity, our construction is based on the principle that the free theory of the cubic curvature theory reduces to one of the three known unitary theories which are the cosmological Einstein-Hilbert theory, the quadratic theory of the scalar curvature, or the new massive gravity (NMG). Bulk and boundary unitarity in NMG is in conflict; therefore, cubic theories that are unitary both in the bulk and on the boundary have free theories that reduce to the other two alternatives. We also study the unitarity of the Born-Infeld extensions of NMG to all orders in curvature.
Effective Field Theories from Soft Limits of Scattering Amplitudes
NASA Astrophysics Data System (ADS)
Cheung, Clifford; Kampf, Karol; Novotny, Jiri; Trnka, Jaroslav
2015-06-01
We derive scalar effective field theories—Lagrangians, symmetries, and all—from on-shell scattering amplitudes constructed purely from Lorentz invariance, factorization, a fixed power counting order in derivatives, and a fixed order at which amplitudes vanish in the soft limit. These constraints leave free parameters in the amplitude which are the coupling constants of well-known theories: Nambu-Goldstone bosons, Dirac-Born-Infeld scalars, and Galilean internal shift symmetries. Moreover, soft limits imply conditions on the Noether current which can then be inverted to derive Lagrangians for each theory. We propose a natural classification of all scalar effective field theories according to two numbers which encode the derivative power counting and soft behavior of the corresponding amplitudes. In those cases where there is no consistent amplitude, the corresponding theory does not exist.
BTZ-like black holes in even dimensional Lovelock theories
Canfora, Fabrizio; Giacomini, Alex
2010-07-15
In the present paper, a new class of black hole solutions is constructed in even dimensional Lovelock Born-Infeld theory. These solutions are interesting since, in some respects, they are closer to black hole solutions of an odd dimensional Lovelock Chern-Simons theory than to the more usual black hole solutions in even dimensions. This hybrid behavior arises when non-Einstein base manifolds are considered. The entropies of these solutions have been analyzed using Wald formalism. These metrics exhibit a quite nontrivial behavior. Their entropies can change sign and can even be identically zero depending on the geometry of the corresponding base manifolds. Therefore, the request of thermodynamical stability constrains the geometry of the non-Einstein base manifolds. It will be shown that some of these solutions can support nonvanishing torsion. Eventually, the possibility to define a sort of topological charge associated with torsion will be discussed.
Vacuum static compactified wormholes in eight-dimensional Lovelock theory
Canfora, Fabrizio; Giacomini, Alex
2008-10-15
In this paper, new exact solutions in eight-dimensional Lovelock theory will be presented. These solutions are the vacuum static wormhole, the black hole, and generalized Bertotti-Robinson space-times with nontrivial torsion. All of the solutions have a cross product structure of the type M{sub 5}x{sigma}{sub 3}, where M{sub 5} is a five-dimensional manifold and {sigma}{sub 3} a compact constant curvature manifold. The wormhole is the first example of a smooth vacuum static Lovelock wormhole which is neither Chern-Simons nor Born-Infeld. It will be also discussed how the presence of torsion affects the 'navigableness' of the wormhole for scalar and spinning particles. It will be shown that the wormhole with torsion may act as 'geometrical filter': A very large torsion may 'increase the traversability' for scalars while acting as a 'polarizator' on spinning particles. This may have interesting phenomenological consequences.
The Nonlinear Field Space Theory
NASA Astrophysics Data System (ADS)
Mielczarek, Jakub; Trześniewski, Tomasz
2016-08-01
In recent years the idea that not only the configuration space of particles, i.e. spacetime, but also the corresponding momentum space may have nontrivial geometry has attracted significant attention, especially in the context of quantum gravity. The aim of this letter is to extend this concept to the domain of field theories, by introducing field spaces (i.e. phase spaces of field values) that are not affine spaces. After discussing the motivation and general aspects of our approach we present a detailed analysis of the prototype (quantum) Nonlinear Field Space Theory of a scalar field on the Minkowski background. We show that the nonlinear structure of a field space leads to numerous interesting predictions, including: non-locality, generalization of the uncertainty relations, algebra deformations, constraining of the maximal occupation number, shifting of the vacuum energy and renormalization of the charge and speed of propagation of field excitations. Furthermore, a compact field space is a natural way to implement the "Principle of finiteness" of physical theories, which once motivated the Born-Infeld theory. Thus the presented framework has a variety of potential applications in the theories of fundamental interactions (e.g. quantum gravity), as well as in condensed matter physics (e.g. continuous spin chains), and can shed new light on the issue of divergences in quantum field theories.
Circumventing the eta problem in building an inflationary model in string theory
Easson, Damien A.; Gregory, Ruth
2009-10-15
The eta problem is one of the most significant obstacles to building a successful inflationary model in string theory. Planck mass suppressed corrections to the inflaton potential generally lead to inflaton masses of order the Hubble scale and generate contributions of order unity to the {eta} slow-roll parameter rendering prolonged slow-roll inflation impossible. We demonstrate the severity of this problem in the context of brane antibrane inflation in a warped throat of a Calabi-Yau flux compactification with all phenomenologically dangerous moduli stabilized. Using numerical solutions we show that the eta problem can be avoided in scenarios where the inflaton is nonminimally coupled to gravity and has Dirac-Born-Infeld kinetic term. We show that the resulting cosmic microwave background observables such as measures of non-Gaussianites can, in principle, serve as a probe of scalar-gravity couplings.
Covariantized matrix theory for D-particles
NASA Astrophysics Data System (ADS)
Yoneya, Tamiaki
2016-06-01
We reformulate the Matrix theory of D-particles in a manifestly Lorentz-covariant fashion in the sense of 11 dimesnional flat Minkowski space-time, from the view-point of the so-called DLCQ interpretation of the light-front Matrix theory. The theory is characterized by various symmetry properties including higher gauge symmetries, which contain the usual SU( N ) symmetry as a special case and are extended from the structure naturally appearing in association with a discretized version of Nambu's 3-bracket. The theory is scale invariant, and the emergence of the 11 dimensional gravitational length, or M-theory scale, is interpreted as a consequence of a breaking of the scaling symmetry through a super-selection rule. In the light-front gauge with the DLCQ compactification of 11 dimensions, the theory reduces to the usual light-front formulation. In the time-like gauge with the ordinary M-theory spatial compactification, it reduces to a non-Abelian Born-Infeld-like theory, which in the limit of large N becomes equivalent with the original BFSS theory.
Extensions of theories from soft limits
NASA Astrophysics Data System (ADS)
Cachazo, Freddy; Cha, Peter; Mizera, Sebastian
2016-06-01
We study a variety of field theories with vanishing single soft limits. In all cases, the structure of the soft limit is controlled by a larger theory, which provides an extension of the original one by adding more fields and interactions. Our main example is the U( N ) non-linear sigma model in its CHY representation. Its extension is a theory in which the NLSM Goldstone bosons interact with a cubic biadjoint scalar. Other theories we study and extend are the special Galileon and Born-Infeld theory, including its maximally supersymmetric version in four dimensions, the DBI-Volkov-Akulov theory. In all the cases, we propose the CHY representation of the complete tree-level S-matrix of the extended theories. In fact, CHY formulas are the key technique for studying the single soft limit behavior of the original theories. As a byproduct, we show that the tree-level S-matrix of the extended NLSM theory can be constructed using a very compact BCFW-like recursion relation, where physical poles are at most linear in the deformation parameter.
DBI scalar field theory for QGP hydrodynamics
NASA Astrophysics Data System (ADS)
Nastase, Horatiu
2016-07-01
A way to describe the hydrodynamics of the quark-gluon plasma using a Dirac-Born-Infeld (DBI) action is proposed, based on the model found by Heisenberg for high energy scattering of nucleons. The expanding plasma is described as a shockwave in a DBI model for a real scalar standing in for the pion, and I show that one obtains a fluid description in terms of a relativistic fluid that near the shock is approximately ideal (η ≃0 ) and conformal. One can introduce an extra term inside the square root of the DBI action that generates a shear viscosity term in the energy-momentum tensor near the shock, as well as a bulk viscosity, and regulates the behavior of the energy density at the shock, making it finite. The resulting fluid satisfies the relativistic Navier-Stokes equation with uμ,ρ ,P ,η defined in terms of ϕ and its derivatives. One finds a relation between the parameters of the theory and the quark-gluon plasma thermodynamics, α /β2=η /(s T ), and by fixing α and β from usual (low multiplicity) particle scattering, one finds T ∝mπ.
Gauge transformation of double field theory for open string
NASA Astrophysics Data System (ADS)
Ma, Chen-Te
2015-09-01
We combine symmetry structures of ordinary (parallel directions) and dual (transversal directions) coordinates to construct the Dirac-Born-Infeld theory. The ordinary coordinates are associated with the Neumann boundary conditions and the dual coordinates are associated with the Dirichlet boundary conditions. Gauge fields become scalar fields by exchanging the ordinary and dual coordinates. A gauge transformation of a generalized metric is governed by the generalized Lie derivative. The gauge transformation of the massless closed string theory gives the C -bracket, but the gauge transformation of the open string theory gives the F -bracket. The F -bracket with the strong constraints is different from the Courant bracket by an exact one-form. This exact one-form should come from the one-form gauge field. Based on a symmetry point of view, we deduce a suitable action with a nonzero H -flux at the low-energy level. From an equation of motion of the scalar dilaton, it defines a generalized scalar curvature. Finally, we construct a double sigma model with a boundary term and show that this model with constraints is classically equivalent to the ordinary sigma model.
Testing universal relations of neutron stars with a nonlinear matter-gravity coupling theory
Sham, Y.-H.; Lin, L.-M.; Leung, P. T. E-mail: lmlin@phy.cuhk.edu.hk
2014-02-01
Due to our ignorance of the equation of state (EOS) beyond nuclear density, there is still no unique theoretical model for neutron stars (NSs). It is therefore surprising that universal EOS-independent relations connecting different physical quantities of NSs can exist. Lau et al. found that the frequency of the f-mode oscillation, the mass, and the moment of inertia are connected by universal relations. More recently, Yagi and Yunes discovered the I-Love-Q universal relations among the mass, the moment of inertia, the Love number, and the quadrupole moment. In this paper, we study these universal relations in the Eddington-inspired Born-Infeld (EiBI) gravity. This theory differs from general relativity (GR) significantly only at high densities due to the nonlinear coupling between matter and gravity. It thus provides us an ideal case to test how robust the universal relations of NSs are with respect to the change of the gravity theory. Due to the apparent EOS formulation of EiBI gravity developed recently by Delsate and Steinhoff, we are able to study the universal relations in EiBI gravity using the same techniques as those in GR. We find that the universal relations in EiBI gravity are essentially the same as those in GR. Our work shows that, within the currently viable coupling constant, there exists at least one modified gravity theory that is indistinguishable from GR in view of the unexpected universal relations.
Aspects of inflation in string theory
NASA Astrophysics Data System (ADS)
Baumann, Daniel
2008-10-01
In this thesis we make small steps towards the ambitious goal of a microphysical understanding of the inflationary era in the early universe. We identify three key questions that require a proper understanding of the ultraviolet limit of the theory: (i) the delicate flatness of the inflaton potential, (ii) the possibility of observable gravitational waves and (iii) a large non-Gaussianity of the primordial density fluctuations. We study these fundamental aspects of inflation in the context of string theory. V (φ): In the first half of the thesis, we give the first fully explicit derivation of the potential for warped D-brane inflation. The analysis exposes the eta-problem, relates effective parameters in the inflaton Lagrangian to microscopic string theory input, and illustrates important correlations between the parameters of the potential. We show that compactification constraints significantly limit the possibility of obtaining inflationary solutions in these scenarios. r: All inflationary models that predict an observable gravitational wave signal require that the inflaton field evolves over a super-Planckian range. In the second half of the thesis, we derive a microscopic bound on the maximal inflaton field variation for D-brane models. The bound arises from the compact nature of the extra dimensions and puts a strong upper limit on the gravitational wave signal. fNL: Finally, we explain that our limit on the field range also significantly constrains the parameter space of Dirac-Born-Infeld inflation. In this case the bound strongly restricts the possibility of a large non-Gaussianity in the primordial fluctuations.
Study on a Unified Model of Dark Matter and Dark Energy from Dbi Theory
NASA Astrophysics Data System (ADS)
Lu, Jianbo; Xu, Lixin; Wu, Yabo; Liu, Molin; Li, Tianqiang
2013-07-01
In this paper, we study a unified model of dark matter and dark energy obtained from Dirac-Born-Infeld (DBI) action in string theory. Two accelerated expansions in universe can be unified in this action. By using the Markov Chain Monte Carlo method, we fit the current observational data to constrain the model parameters in this unified model, where various density parameters as model parameters are included, and their constraint values are: Ω K = -0.0012+0.0037+0.0072-0.0036-0.0071, Ω b = 0.0461+0.0009+0.0017-0.0009-0.0017, Ω f = 0.171+0.108+0.195-0.108-0.160 and Ω 0m = 0.281+0.011+0.020-0.011-0.021. In addition, the Hubble constant and cosmic age are H0 = 70.163+1.029+2.045-1.029-1.988 and Age =13.788+0.160+0.318-0.160-0.312 (Gyr), respectively. According to the constraint results on model parameters we discuss the evolutions of some cosmological quantities in structure formation, such as the density contrast and the growth variable. At last, the evolution of geometrical quantity is studied to distinguish the unified models of dark sectors with the cosmological constant model. It is shown that this unified model of dark matter and dark energy is attractive to interpret the accelerating universe.
Coulomb's Law Modification in Nonlinear and in Noncommutative Electrodynamics
NASA Astrophysics Data System (ADS)
Gaete, Patricio; Schmidt, Iván
We study the lowest-order modifications of the static potential for Born-Infeld electrodynamics and for the θ-expanded version of the noncommutative U(1) gauge theory, within the framework of the gauge-invariant but path-dependent variables formalism. The calculation shows a long-range correction (1/r5-type) to the Coulomb potential in Born-Infeld electrodynamics. However, the Coulomb nature of the potential (to order e2) is preserved in noncommutative electrodynamics.
Tunneling in quantum field theory and semiclassical gravity
NASA Astrophysics Data System (ADS)
Wohns, Dan Funch
In this dissertation we discuss aspects of the transitions between metastable vacua in scalar field theories. These transitions are caused by nucleation of bubbles of one vacuum in a background of another vacuum, and may have relevance in cosmology. Such processes are typically exponentially suppressed in the height and width of the barriers between the vacua. We demonstrate several scenarios where this intuition fails. We use a functional Schrodinger approach to show that tunneling of a scalar field through two barriers can be exponentially faster than tunneling through a single barrier. We determine the conditions that the effective potential must satisfy for a large enhancement in the tunneling rate to be possible. Both the tunneling rate to nearby vacua and to distant vacua in field space can be enhanced by this process. It may be possible to test this phenomenon using superfluid Helium-3. Nucleation of the B phase in samples of the supercooled A phase of superfluid Helium-3 is observed in seconds or minutes, while the characteristic decay time is calculated to be longer than the age of the universe. We propose a resolution to this discrepancy using resonant tunneling. This explanation makes the distinctive prediction that there exist multiple peaks in the nucleation probability as a function of temperature, pressure, and magnetic field. Next we investigate in detail Coleman-de Luccia tunneling. We show that there are four types of tunneling, depending on the importance of thermal and horizon effects. We estimate corrections to the Hawking-Moss tunneling rate, which can be large. Finally, the tunneling rate for a scalar field described by the Dirac-Born-Infeld action is calculated in the Hawking-Moss limit using a stochastic approach.
Charged anti-de Sitter scalar-tensor black holes and their thermodynamic phase structure
Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Kokkotas, Kostas D.; Stefanov, Ivan Zh.; Todorov, Michail D.
2010-05-15
In the present paper we numerically construct new charged anti-de Sitter black holes coupled to nonlinear Born-Infeld electrodynamics within a certain class of scalar-tensor theories. The properties of the solutions are investigated both numerically and analytically. We also study the thermodynamics of the black holes in the canonical ensemble. For large values of the Born-Infeld parameter and for a certain interval of the charge values we find the existence of a first-order phase transition between small and very large black holes. An unexpected result is that for a certain small charge subinterval two phase transitions have been observed, one of zeroth and one of first order. It is important to note that such phase transitions are also observed for pure Einstein-Born-Infeld-AdS black holes.
Non-perturbative aspects of particle acceleration in non-linear electrodynamics
NASA Astrophysics Data System (ADS)
Burton, David A.; Flood, Stephen P.; Wen, Haibao
2015-04-01
We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can "surf" a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.
Non-perturbative aspects of particle acceleration in non-linear electrodynamics
Burton, David A.; Flood, Stephen P.; Wen, Haibao
2015-04-15
We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can “surf” a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.
Skyrme-like models and supersymmetry in 3 +1 dimensions
NASA Astrophysics Data System (ADS)
Queiruga, J. M.
2015-11-01
We construct supersymmetric extensions for different Skyrme-like models in 3 +1 dimensions. BPS equations and BPS bounds are obtained from supersymmetry in some cases. We discuss also the emergence of several Skyrme-like models from supersymmetric Yang-Mills theory and Born-Infeld theory in 5 dimensions.
Off-shell D-brane action at order α'2 in flat spacetime
NASA Astrophysics Data System (ADS)
Garousi, Mohammad R.
2016-03-01
We use compatibility of the second fundamental form corrections to Dirac-Born-Infeld action at order α'2 which includes the trace of the second fundamental form, with T-duality and with the linear S-duality as guiding principles, to find an off-shell D-brane action at order α'2 in type II superstring theories in flat spcetime.
Constructing Graphs over with Small Prescribed Mean-Curvature
NASA Astrophysics Data System (ADS)
Carley, Holly; Kiessling, Michael K.-H.
2015-12-01
In this paper nonlinear Hodge theory and Banach algebra estimates are employed to construct a convergent series expansion which solves the prescribed mean curvature equation for n-dimensional hypersurfaces in (+ sign) and (- sign) which are graphs of a smooth function , and whose mean curvature function H is α-Hölder continuous and integrable, with small norm. The radius of convergence is estimated explicitly from below. Our approach is inspired by, and applied to, the Maxwell-Born-Infeld theory of electromagnetism in , for which our method yields the first systematic way of explicitly computing the electrostatic potential for regular charge densities and small Born parameter, with explicit error estimates at any order of truncation of the series. In particular, our results level the ground for a controlled computation of Born-Infeld effects on the Hydrogen spectrum.
Relations between canonical and non-canonical inflation
Gwyn, Rhiannon; Rummel, Markus; Westphal, Alexander E-mail: markus.rummel@physics.ox.ac.uk
2013-12-01
We look for potential observational degeneracies between canonical and non-canonical models of inflation of a single field φ. Non-canonical inflationary models are characterized by higher than linear powers of the standard kinetic term X in the effective Lagrangian p(X,φ) and arise for instance in the context of the Dirac-Born-Infeld (DBI) action in string theory. An on-shell transformation is introduced that transforms non-canonical inflationary theories to theories with a canonical kinetic term. The 2-point function observables of the original non-canonical theory and its canonical transform are found to match in the case of DBI inflation.
Scattering equations and matrices: from Einstein to Yang-Mills, DBI and NLSM
NASA Astrophysics Data System (ADS)
Cachazo, Freddy; He, Song; Yuan, Ellis Ye
2015-07-01
The tree-level S-matrix of Einstein's theory is known to have a representation as an integral over the moduli space of punctured spheres localized to the solutions of the scattering equations. In this paper we introduce three operations that can be applied on the integrand in order to produce other theories. Starting in d + M dimensions we use dimensional reduction to construct Einstein-Maxwell with gauge group U(1) M . The second operation turns gravitons into gluons and we call it "squeezing". This gives rise to a formula for all multi-trace mixed amplitudes in Einstein-Yang-Mills. Dimensionally reducing Yang-Mills we find the S-matrix of a special Yang-Mills-Scalar (YMS) theory, and by the squeezing operation we find that of a YMS theory with an additional cubic scalar vertex. A corollary of the YMS formula gives one for a single massless scalar with a ϕ 4 interaction. Starting again from Einstein's theory but in d + d dimensions we introduce a "generalized dimensional reduction" that produces the Born-Infeld theory or a special Galileon theory in d dimensions depending on how it is applied. An extension of Born-Infeld formula leads to one for the Dirac-Born-Infeld (DBI) theory. By applying the same operation to Yang-Mills we obtain the U( N ) non-linear sigma model (NLSM). Finally, we show how the Kawai-Lewellen-Tye relations naturally follow from our formulation and provide additional connections among these theories. One such relation constructs DBI from YMS and NLSM.
Some remarks on unilateral matrix equations
Cerchiai, Bianca L.; Zumino, Bruno
2001-02-01
We briefly review the results of our paper LBNL-46775: We study certain solutions of left-unilateral matrix equations. These are algebraic equations where the coefficients and the unknown are square matrices of the same order, or, more abstractly, elements of an associative, but possibly noncommutative algebra, and all coefficients are on the left. Recently such equations have appeared in a discussion of generalized Born-Infeld theories. In particular, two equations, their perturbative solutions and the relation between them are studied, applying a unified approach based on the generalized Bezout theorem for matrix polynomials.
Deformations with maximal supersymmetries part 2: off-shell formulation
NASA Astrophysics Data System (ADS)
Chang, Chi-Ming; Lin, Ying-Hsuan; Wang, Yifan; Yin, Xi
2016-04-01
Continuing our exploration of maximally supersymmetric gauge theories (MSYM) deformed by higher dimensional operators, in this paper we consider an off-shell approach based on pure spinor superspace and focus on constructing supersymmetric deformations beyond the first order. In particular, we give a construction of the Batalin-Vilkovisky action of an all-order non-Abelian Born-Infeld deformation of MSYM in the non-minimal pure spinor formalism. We also discuss subtleties in the integration over the pure spinor superspace and the relevance of Berkovits-Nekrasov regularization.
Modified gravity in three dimensional metric-affine scenarios
NASA Astrophysics Data System (ADS)
Bambi, Cosimo; Ghasemi-Nodehi, M.; Rubiera-Garcia, D.
2015-08-01
We consider metric-affine scenarios where a modified gravitational action is sourced by electrovacuum fields in a three dimensional space-time. We first study the case of f (R ) theories, finding deviations near the center as compared to the solutions of general relativity. We then consider Born-Infeld gravity, which has raised a lot of interest in the last few years regarding its applications in astrophysics and cosmology, and show that new features always arise at a finite distance from the center. Several properties of the resulting space-times, in particular in presence of a cosmological constant term, are discussed.
About non standard Lagrangians in cosmology
Dimitrijevic, Dragoljub D.; Milosevic, Milan
2012-08-17
A review of non standard Lagrangians present in modern cosmological models will be considered. Well known example of non standard Lagrangian is Dirac-Born-Infeld (DBI) type Lagrangian for tachyon field. Another type of non standard Lagrangian under consideration contains scalar field which describes open p-adic string tachyon and is called p-adic string theory Lagrangian. We will investigate homogenous cases of both DBI and p-adic fields and obtain Lagrangians of the standard type which have the same equations of motions as aforementioned non standard one.
Slowly rotating black holes with nonlinear electrodynamics in five dimensions
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Sepehri Rad, M.
2014-10-01
Employing linear order perturbation theory with the rotation parameter as the perturbative parameter, we obtain asymptotically AdS slowly rotating black hole solutions in the Einstein gravity with Born-Infeld (BI) type nonlinear electrodynamics (NED). We start from asymptotically AdS static black hole solutions coupled to BI type NED in five dimensions. Then, we consider the effect of adding a small amount of angular momenta to the seed solutions. Finally, we investigate the geometry and thermodynamic properties of the solutions.
Massive gravity coupled to Galileons is ghost-free.
Andrews, Melinda; Goon, Garrett; Hinterbichler, Kurt; Stokes, James; Trodden, Mark
2013-08-01
It is possible to couple Dirac-Born-Infeld 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. PMID:23971555
Four wave mixing as a probe of the vacuum
NASA Astrophysics Data System (ADS)
Tennant, Daniel M.
2016-06-01
Much attention has been paid to the quantum structure of the vacuum. Higher order processes in quantum electrodynamics are strongly believed to cause polarization and even breakdown of the vacuum in the presence of strong fields soon to be accessible in high intensity laser experiments. Less explored consequences of strong field electrodynamics include effects from Born-Infeld type of electromagnetic theories, a nonlinear electrodynamics that follows from classical considerations as opposed to coupling to virtual fluctuations. In this article, I will demonstrate how vacuum four wave mixing has the possibility to differentiate between these two types of vacuum responses: quantum effects on one hand and nonlinear classical extensions on the other.
Distinguishing k-defects from their canonical twins
Andrews, Melinda; Lewandowski, Matt; Trodden, Mark; Wesley, Daniel
2010-11-15
We study k-defects--topological defects in theories with more than two derivatives and second-order equations of motion--and describe some striking ways in which these defects both resemble and differ from their analogues in canonical scalar field theories. We show that, for some models, the homotopy structure of the vacuum manifold is insufficient to establish the existence of k-defects, in contrast to the canonical case. These results also constrain certain families of Dirac-Born-Infeld instanton solutions in the 4-dimensional effective theory. We then describe a class of k-defect solutions, which we dub ''doppelgaengers,'' that precisely match the field profile and energy density of their canonical scalar field theory counterparts. We give a complete characterization of Lagrangians which admit doppelgaenger domain walls. By numerically computing the fluctuation eigenmodes about domain wall solutions, we find different spectra for doppelgaengers and canonical walls, allowing us to distinguish between k-defects and the canonical walls they mimic. We search for doppelgaengers for cosmic strings by numerically constructing solutions of Dirac-Born-Infeld and canonical scalar field theories. Despite investigating several examples, we are unable to find doppelgaenger cosmic strings, hence the existence of doppelgaengers for defects with codimension >1 remains an open question.
String Theory and Gauge Theories
Maldacena, Juan
2009-02-20
We will see how gauge theories, in the limit that the number of colors is large, give string theories. We will discuss some examples of particular gauge theories where the corresponding string theory is known precisely, starting with the case of the maximally supersymmetric theory in four dimensions which corresponds to ten dimensional string theory. We will discuss recent developments in this area.
Easson, Damien A; Gregory, Ruth; Mota, David F; Tasinato, Gianmassimo; Zavala, Ivonne E-mail: r.a.w.gregory@durham.ac.uk E-mail: tasinato@thphys.ox.ac.uk
2008-02-15
We study the cosmological implications of including angular motion in the Dirac-Born-Infeld brane inflation scenario. The non-canonical kinetic terms of the Dirac-Born-Infeld action give an interesting alternative to slow-roll inflation, and cycling branes can drive periods of accelerated expansion in the Universe. We present explicit numerical solutions demonstrating brane inflation in the Klebanov-Strassler throat. We find that demanding sufficient inflation takes place in the throat is in conflict with keeping the brane's total energy low enough that local gravitational back-reaction on the Calabi-Yau manifold can be safely ignored. We deduce that spinflation (brane inflation with angular momentum) can ease this tension by providing extra e-foldings at the start of inflation. Cosmological expansion rapidly damps the angular momentum causing an exit to a more conventional brane inflation scenario. Finally, we set up a general framework for cosmological perturbation theory in this scenario, where we have multi-field non-standard kinetic term inflation.
ERIC Educational Resources Information Center
Williams, Jeffrey
1994-01-01
Considers the recent flood of anthologies of literary criticism and theory as exemplifications of the confluence of pedagogical concerns, economics of publishing, and other historical factors. Looks specifically at how these anthologies present theory. Cites problems with their formatting theory and proposes alternative ways of organizing theory…
Scattering equations, twistor-string formulas and double-soft limits in four dimensions
NASA Astrophysics Data System (ADS)
He, Song; Liu, Zhengwen; Wu, Jun-Bao
2016-07-01
We study scattering equations and formulas for tree amplitudes of various theories in four dimensions, in terms of spinor helicity variables and on-shell superspace for supersymmetric theories. As originally obtained in Witten's twistor string theory and other twistor-string models, the equations can take either polynomial or rational forms, and we clarify the simple relation between them. We present new, four-dimensional formulas for all tree amplitudes in the non-linear sigma model, a special Galileon theory and the maximally supersymmetric completion of the Dirac-Born-Infeld theory. Furthermore, we apply the formulas to study various double-soft theorems in these theories, including the emissions of a pair of soft photons, fermions and scalars for super-amplitudes in super-DBI theory.
Sanfilippo, Antonio P.
2005-12-27
Graph theory is a branch of discrete combinatorial mathematics that studies the properties of graphs. The theory was pioneered by the Swiss mathematician Leonhard Euler in the 18th century, commenced its formal development during the second half of the 19th century, and has witnessed substantial growth during the last seventy years, with applications in areas as diverse as engineering, computer science, physics, sociology, chemistry and biology. Graph theory has also had a strong impact in computational linguistics by providing the foundations for the theory of features structures that has emerged as one of the most widely used frameworks for the representation of grammar formalisms.
NASA Astrophysics Data System (ADS)
Solari, Soren; Smith, Andrew; Minnett, Rupert; Hecht-Nielsen, Robert
2008-06-01
Confabulation Theory [Hecht-Nielsen R. Confabulation theory. Springer-Verlag; 2007] is the first comprehensive theory of human and animal cognition. Here, we briefly describe Confabulation Theory and discuss experimental results that suggest the theory is correct. Simply put, Confabulation Theory proposes that thinking is like moving. In humans, the theory postulates that there are roughly 4000 thalamocortical modules, the “muscles of thought”. Each module performs an internal competition ( confabulation) between its symbols, influenced by inputs delivered via learned axonal associations with symbols in other modules. In each module, this competition is controlled, as in an individual muscle, by a single graded (i.e., analog) thought control signal. The final result of this confabulation process is a single active symbol, the expression of which also results in launching of action commands that trigger and control subsequent movements and/or thought processes. Modules are manipulated in groups under coordinated, event-contingent control, in a similar manner to our 700 muscles. Confabulation Theory hypothesizes that the control of thinking is a direct evolutionary outgrowth of the control of movement. Establishing a complete understanding of Confabulation Theory will require launching and sustaining a massive new phalanx of confabulation neuroscience research.
Interacting spin-2 fields in the Stückelberg picture
Noller, Johannes; Ferreira, Pedro G.; Scargill, James H.C. E-mail: james.scargill@physics.ox.ac.uk
2014-02-01
We revisit and extend the 'Effective field theory for massive gravitons' constructed by Arkani-Hamed, Georgi and Schwartz in the light of recent progress in constructing ghost-free theories with multiple interacting spin-2 fields. We show that there exist several dual ways of restoring gauge invariance in such multi-gravity theories, find a generalised Fierz-Pauli tuning condition relevant in this context and highlight subtleties in demixing tensor and scalar modes. The generic multi-gravity feature of scalar mixing and its consequences for higher order interactions are discussed. In particular we show how the decoupling limit is qualitatively changed in theories of interacting spin-2 fields. We relate this to dRGT (de Rham, Gabadadze, Tolley) massive gravity, Hassan-Rosen bigravity and the multi-gravity constructions by Hinterbichler and Rosen. As an additional application we show that EBI (Eddington-Born-Infeld) bigravity and higher order generalisations thereof possess ghost-like instabilities.
Interacting spin-2 fields in the Stückelberg picture
NASA Astrophysics Data System (ADS)
Noller, Johannes; Scargill, James H. C.; Ferreira, Pedro G.
2014-02-01
We revisit and extend the `Effective field theory for massive gravitons' constructed by Arkani-Hamed, Georgi and Schwartz in the light of recent progress in constructing ghost-free theories with multiple interacting spin-2 fields. We show that there exist several dual ways of restoring gauge invariance in such multi-gravity theories, find a generalised Fierz-Pauli tuning condition relevant in this context and highlight subtleties in demixing tensor and scalar modes. The generic multi-gravity feature of scalar mixing and its consequences for higher order interactions are discussed. In particular we show how the decoupling limit is qualitatively changed in theories of interacting spin-2 fields. We relate this to dRGT (de Rham, Gabadadze, Tolley) massive gravity, Hassan-Rosen bigravity and the multi-gravity constructions by Hinterbichler and Rosen. As an additional application we show that EBI (Eddington-Born-Infeld) bigravity and higher order generalisations thereof possess ghost-like instabilities.
New Massive Gravity and AdS{sub 4} Counterterms
Jatkar, Dileep P.; Sinha, Aninda
2011-04-29
We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS{sub 4}). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS{sub 4} Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS{sub 3} gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory.
New massive gravity and AdS(4) counterterms.
Jatkar, Dileep P; Sinha, Aninda
2011-04-29
We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS(4)). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS(4) Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS(3) gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory. PMID:21635026
NASA Astrophysics Data System (ADS)
Susskind, Leonard
2013-01-01
After reviewing the original motivation for the formulation of string theory and what we learned from it, I discuss some of the implications of the holographic principle and of string dualities for the question of the building blocks of nature.
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
A theory based on the premise that, on the microscopic scale, physical quantities have discrete, rather than a continuous range of, values. The theory was devised in the early part of the twentieth century to account for certain phenomena that could not be explained by classical physics. In 1900, the German physicist, Max Planck (1858-1947), was able precisely to describe the previously unexplaine...
New double soft emission theorems
NASA Astrophysics Data System (ADS)
Cachazo, Freddy; He, Song; Yuan, Ellis Ye
2015-09-01
We study the behavior of the tree-level S-matrix of a variety of theories as two particles become soft. By analogy with the recently found subleading soft theorems for gravitons and gluons, we explore subleading terms in double soft emissions. We first consider double soft scalar emissions and find subleading terms that are controlled by the angular momentum operator acting on hard particles. The order of the subleading theorems depends on the presence or not of color structures. Next we obtain a compact formula for the leading term in a double soft photon emission. The theories studied are a special Galileon, Dirac-Born-Infeld, Einstein-Maxwell-Scalar, nonlinear sigma model and Yang-Mills-Scalar. We use the recently found Cachazo-He-Yuan representation of these theories in order to give a simple proof of the leading order part of all these theorems.
More on closed string induced higher derivative interactions on D-branes
NASA Astrophysics Data System (ADS)
Hatefi, Ehsan; Park, I. Y.
2012-06-01
In our continued efforts of matching full string computations with the corresponding effective field theory computations, we evaluate string theory correlators in closed forms. In particular, we consider a correlator between three super Yang-Mills vertex operators and one Ramond-Ramond C-field vertex operator: ⟨VCVϕVAVA⟩. We show that the infinite number of massless poles of this amplitude can be reproduced by the Born-Infeld action, the Wess-Zumino terms, and their higher derivative corrections. More specifically, we find, up to an on-shell ambiguity, two scalar field and two gauge field couplings to all orders in α' such that the infinite number of massless poles of the field theory amplitude exactly match the infinite number of massless poles of the S-matrix elements of ⟨VCVϕVAVA⟩. We comment on the close intertwinedness of an open string and a closed string that must be behind the matching.
Observational signatures of gravitational couplings in DBI inflation
Easson, Damien A.; Mukohyama, Shinji; Powell, Brian A.
2010-01-15
In scalar-tensor theories the scalar fields generically couple nontrivially to gravity. We study the observable properties of inflationary models with nonminimally coupled inflaton and Dirac-Born-Infeld (DBI) kinetic term. Within the assumptions of the priors of our Monte-Carlo simulations we find these models can generate new interesting observable signatures. Our discussion focuses on string theory inspired phenomenological models of relativistic D-brane inflation. While successful string theory constructions of ultraviolet DBI brane inflation remain elusive, we show that in suitable regions of the parameter space it is possible to use cosmological observables to probe the nonminimal coupling. Fortunately, the most observationally promising range of parameters include models yielding intermediate levels of non-Gaussianity in the range consistent with WMAP 5-year data, and to be constrained further by the Planck satellite.
Effective theories of universal theories
NASA Astrophysics Data System (ADS)
Wells, James D.; Zhang, Zhengkang
2016-01-01
It is well-known but sometimes overlooked that constraints on the oblique parameters (most notably S and T parameters) are generally speaking only applicable to a special class of new physics scenarios known as universal theories. In the effective field theory (EFT) framework, the oblique parameters should not be associated with Wilson coefficients in a particular operator basis, unless restrictions have been imposed on the EFT so that it describes universal theories. We work out these restrictions, and present a detailed EFT analysis of universal theories. We find that at the dimension-6 level, universal theories are completely characterized by 16 parameters. They are conveniently chosen to be: 5 oblique parameters that agree with the commonly-adopted ones, 4 anomalous triple-gauge couplings, 3 rescaling factors for the h 3, hf f , hV V vertices, 3 parameters for hV V vertices absent in the Standard Model, and 1 four-fermion coupling of order y f 2 . All these parameters are defined in an unambiguous and basis-independent way, allowing for consistent constraints on the universal theories parameter space from precision electroweak and Higgs data.
NASA Astrophysics Data System (ADS)
Moraru, Gheorghe; Mursa, Condrat
2006-12-01
In this book we present the basic concepts of the theory of elasticity: stress and deformation states (plane and three-dimensional) and generalized Hooke's law. We present a number of problems which have applications in strength analysis. The book includes a synthesis of the theory of elasticity and modern methods of applied mathematics. This book is designed for students, post graduate students and specialists in strength analysis. the book contains a number of appendixes which includes: elements of matrix-calculation, concepts of tensorial calculation, the Fourier transform, the notion of improper integrals,singular and hypersingular integrals, generalized functions, the Dirac Delta function
ERIC Educational Resources Information Center
Moorman, Thomas
1992-01-01
Students experience the distinction between observable fact and scientific theory by taking a critical look at how spaghetti can be sucked up into the mouth. A demonstration shows that air is needed to suck up the spaghetti but that the scientific explanation is not as simple. (MDH)
ERIC Educational Resources Information Center
Toso, Robert B.
2000-01-01
Inspired by William Glasser's Reality Therapy ideas, Control Theory (CT) is a disciplinary approach that stresses people's ability to control only their own behavior, based on internal motivations to satisfy five basic needs. At one North Dakota high school, CT-trained teachers are the program's best recruiters. (MLH)
NASA Astrophysics Data System (ADS)
Paschos, E. A.
2005-01-01
The electroweak theory unifies two basic forces of nature: the weak force and electromagnetism. This book is a concise introduction to the structure of the electroweak theory and its applications. It describes the structure and properties of field theories with global and local symmetries, leading to the construction of the standard model. It describes the new particles and processes predicted by the theory, and compares them with experimental results. It also covers neutral currents, the properties of W and Z bosons, the properties of quarks and mesons containing heavy quarks, neutrino oscillations, CP-asymmetries in K, D, and B meson decays, and the search for Higgs particles. Each chapter contains problems, stemming from the long teaching experience of the author, to supplement the text. This will be of great interest to graduate students and researchers in elementary particle physics. Password protected solutions are available to lecturers at www.cambridge.org/9780521860987. Each chapter has an introduction highlighting its contents and giving a historical perspective. Chapters are cross-referenced, interrelating concepts and sections of the book. Contains 49 exercises
Optimal bispectrum constraints on single-field models of inflation
Anderson, Gemma J.; Regan, Donough; Seery, David E-mail: D.Regan@sussex.ac.uk
2014-07-01
We use WMAP 9-year bispectrum data to constrain the free parameters of an 'effective field theory' describing fluctuations in single-field inflation. The Lagrangian of the theory contains a finite number of operators associated with unknown mass scales. Each operator produces a fixed bispectrum shape, which we decompose into partial waves in order to construct a likelihood function. Based on this likelihood we are able to constrain four linearly independent combinations of the mass scales. As an example of our framework we specialize our results to the case of 'Dirac-Born-Infeld' and 'ghost' inflation and obtain the posterior probability for each model, which in Bayesian schemes is a useful tool for model comparison. Our results suggest that DBI-like models with two or more free parameters are disfavoured by the data by comparison with single-parameter models in the same class.
Wormholes and nonsingular spacetimes in Palatini f (R ) gravity
NASA Astrophysics Data System (ADS)
Bambi, Cosimo; Cardenas-Avendano, Alejandro; Olmo, Gonzalo J.; Rubiera-Garcia, D.
2016-03-01
We reconsider the problem of f (R ) theories of gravity coupled to Born-Infeld theory of electrodynamics formulated in a Palatini approach, where metric and connection are independent fields. By studying electrovacuum configurations in a static and spherically symmetric spacetime, we find solutions which reduce to their Reissner-Nordström counterparts at large distances but undergo important nonperturbative modifications close to the center. Our new analysis reveals that the pointlike singularity is replaced by a finite-size wormhole structure, which provides a geodesically complete and thus nonsingular spacetime, despite the existence of curvature divergences at the wormhole throat. Implications of these results, in particular for the cosmic censorship conjecture, are discussed.
Primordial non-Gaussianity in noncanonical warm inflation
NASA Astrophysics Data System (ADS)
Zhang, Xiao-Min; Zhu, Jian-Yang
2015-03-01
We study the bispectrum of the primordial curvature perturbation on uniform density hypersurfaces generated by a kind of the noncanonical warm inflation, wherein the inflation is provided by a noncanonical scalar inflaton field that is coupled to radiation through a thermal dissipation effect. We obtain an analytic form for the nonlinear parameter fNL that describes the non-Gaussianity in first-order cosmological perturbation theory and analyze the magnitude of this nonlinear parameter. We make a comparison between our result and those of the standard inflation and the canonical warm inflation. We also discuss when the contribution to the non-Gaussianity due to the second-order perturbation theory becomes more important and what the observations predict. We take the Dirac-Born-Infeld inflation as a concrete example to find how the sound speed and the thermal dissipation strength to decide the non-Gaussianity and get a lower bound of the sound speed constrained by Planck.
Phantom energy mediates a long-range repulsive force.
Amendola, Luca
2004-10-29
Scalar field models with nonstandard kinetic terms have been proposed in the context of k inflation, of Born-Infeld Lagrangians, of phantom energy and, more in general, of low-energy string theory. In general, scalar fields are expected to couple to matter inducing a new interaction. In this Letter I derive the cosmological perturbation equations and the Yukawa correction to gravity for such general models. I find three interesting results: first, when the field behaves as phantom energy (equation of state less than -1), then the coupling strength is negative, inducing a long-range repulsive force; second, the dark-energy field might cluster on astrophysical scales; third, applying the formalism to a Brans-Dicke theory with a general kinetic term it is shown that its Newtonian effects depend on a single parameter that generalizes the Brans-Dicke constant. PMID:15525149
Galileons coupled to massive gravity: general analysis and cosmological solutions
Goon, Garrett; Trodden, Mark; Gümrükçüoğlu, A. Emir; Hinterbichler, Kurt; Mukohyama, Shinji E-mail: Emir.Gumrukcuoglu@nottingham.ac.uk E-mail: shinji.mukohyama@ipmu.jp
2014-08-01
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.
Asymptotically flat black holes in 2 +1 dimensions
NASA Astrophysics Data System (ADS)
Alkaç, Gökhan; Kilicarslan, Ercan; Tekin, Bayram
2016-04-01
Asymptotically flat black holes in 2 +1 dimensions are a rarity. We study the recently found black flower solutions (asymptotically flat black holes with deformed horizons), static black holes, rotating black holes and the dynamical black flowers (black holes with radiative gravitons) of the purely quadratic version of new massive gravity. We show how they appear in this theory and we also show that they are also solutions to the infinite order extended version of the new massive gravity, that is the Born-Infeld extension of new massive gravity with an amputated Einsteinian piece. The same metrics also solve the topologically extended versions of these theories, with modified conserved charges and the thermodynamical quantities, such as the Wald entropy. Besides these we find new conformally flat radiating type solutions to these extended gravity models. We also show that these metrics do not arise in Einstein's gravity coupled to physical perfect fluids.
On the effective character of a non-abelian DBI action
NASA Astrophysics Data System (ADS)
Osorio, M. A. R.; Suárez, M.
2001-03-01
We study the way Lorentz covariance can be reconstructed from Matrix Theory as a IMF description of M-theory. The problem is actually related to the interplay between a non-abelian Dirac-Born-Infeld action and Super-Yang-Mills as its generalized non-relativistic approximation. All this physics shows up by means of an analysis of the asymptotic expansion of the Bessel functions Kν that profusely appear in the computations of amplitudes at finite temperature and solitonic calculations. We hope this might help to better understand the issue of getting a Lorentz covariant formulation in relation with the /N-->+∞ limit. There are also some computations that could be of some interest in Relativistic Statistical Mechanics.
Theory Survey or Survey Theory?
ERIC Educational Resources Information Center
Dean, Jodi
2010-01-01
Matthew Moore's survey of political theorists in U.S. American colleges and universities is an impressive contribution to political science (Moore 2010). It is the first such survey of political theory as a subfield, the response rate is very high, and the answers to the survey questions provide new information about how political theorists look…
NASA Technical Reports Server (NTRS)
Johnson, W.
1980-01-01
A comprehensive presentation is made of the engineering analysis methods used in the design, development and evaluation of helicopters. After an introduction covering the fundamentals of helicopter rotors, configuration and operation, rotary wing history, and the analytical notation used in the text, the following topics are discussed: (1) vertical flight, including momentum, blade element and vortex theories, induced power, vertical drag and ground effect; (2) forward flight, including in addition to momentum and vortex theory for this mode such phenomena as rotor flapping and its higher harmonics, tip loss and root cutout, compressibility and pitch-flap coupling; (3) hover and forward flight performance assessment; (4) helicopter rotor design; (5) rotary wing aerodynamics; (6) rotary wing structural dynamics, including flutter, flap-lag dynamics ground resonance and vibration and loads; (7) helicopter aeroelasticity; (8) stability and control (flying qualities); (9) stall; and (10) noise.
Classical resolution of black hole singularities in arbitrary dimension
NASA Astrophysics Data System (ADS)
Bazeia, D.; Losano, L.; Olmo, Gonzalo J.; Rubiera-Garcia, D.; Sanchez-Puente, A.
2015-08-01
A metric-affine approach is employed to study higher-dimensional modified gravity theories involving different powers and contractions of the Ricci tensor. It is shown that the field equations are always second-order, as opposed to the standard metric approach, where this is only achieved for Lagrangians of the Lovelock type. We point out that this property might have relevant implications for the AdS/CFT correspondence in black hole scenarios. We illustrate these aspects by considering the case of Born-Infeld gravity in d dimensions, where we work out exact solutions for electrovacuum configurations. Our results put forward that black hole singularities in arbitrary dimensions can be cured in a purely classical geometric scenario governed by second-order field equations.
Holographic s-wave condensate with nonlinear electrodynamics: A nontrivial boundary value problem
NASA Astrophysics Data System (ADS)
Banerjee, Rabin; Gangopadhyay, Sunandan; Roychowdhury, Dibakar; Lala, Arindam
2013-05-01
In this paper, considering the probe limit, we analytically study the onset of holographic s-wave condensate in the planar Schwarzschild-AdS background. Inspired by various low-energy features of string theory, in the present work we replace the conventional Maxwell action with a (nonlinear) Born-Infeld action which essentially corresponds to the higher-derivative corrections of the gauge fields. Based on a variational method which is commonly known as the Sturm-Liouville eigenvalue problem and considering a nontrivial asymptotic solution for the scalar field, we compute the critical temperature for the s-wave condensation. The results thus obtained analytically agree well with the numerical findings [J. Jing and S. Chen, Phys. Lett. B 686, 68 (2010)]. As a next step, we extend our perturbative technique to compute the order parameter for the condensation. Interestingly, our analytic results are found to be of the same order as the numerical values obtained earlier.
Emergent cosmological constant from colliding electromagnetic waves
Halilsoy, M.; Mazharimousavi, S. Habib; Gurtug, O. E-mail: habib.mazhari@emu.edu.tr
2014-11-01
In this study we advocate the view that the cosmological constant is of electromagnetic (em) origin, which can be generated from the collision of em shock waves coupled with gravitational shock waves. The wave profiles that participate in the collision have different amplitudes. It is shown that, circular polarization with equal amplitude waves does not generate cosmological constant. We also prove that the generation of the cosmological constant is related to the linear polarization. The addition of cross polarization generates no cosmological constant. Depending on the value of the wave amplitudes, the generated cosmological constant can be positive or negative. We show additionally that, the collision of nonlinear em waves in a particular class of Born-Infeld theory also yields a cosmological constant.
Ellis, John; Mavromatos, Nick E.; Nanopoulos, Dimitri V. E-mail: nikolaos.mavromatos@kcl.ac.uk
2014-11-01
In a recent paper we showed how Starobinsky-like inflation could emerge from dilaton dynamics in brane cosmology scenarios based on string theory, in which our universe is represented as a three-brane and the effective potential acquires a constant term from a density of effectively point-like non-perturbative defects on the brane: ''D-particles''. Here we explore how quantum fluctuations of the ensemble of D-particles during the inflationary period may modify the effective inflationary potential due to the dilaton. We then discuss two specific ways in which an enhanced ratio of tensor to scalar perturbations may arise: via either a condensate of vector fields with a Born-Infeld action that may be due to such recoil fluctuations, or graviton production in the D-particle vacuum.
A fully general relativistic numerical simulation code for spherically symmetric matter
NASA Astrophysics Data System (ADS)
Park, Dong-Ho; Cho, Inyong; Kang, Gungwon; Lee, Hyung Mok
2013-02-01
We present a fully general relativistic open-source code that can be used for simulating a system of spherically symmetric perfect fluid matter. It is based on the Arnowitt-Deser-Misner 3+1 formalism with maximal slicing and isotropic spatial coordinates. For hydrodynamic matter High Resolution Shock Capturing (HRSC) schemes with a monotonized central-difference limiter and approximated Riemann solvers are used in the Eulerian viewpoint. The accuracy and the convergence of our numerical code are verified by performing several test problems. These include a relativistic blast wave, relativistic spherical accretion of matter into a black hole, Tolman-Oppenheimer-Volkoff (TOV) stars and Oppenheimer-Snyder (OS) dust collapses. In particular, a dynamical code test is done for the OS collapse by explicitly performing numerical coordinate transformations between our coordinate 8system and the one used for the analytic solution. Finally, some TOV star solutions are presented for the Eddington-inspired Born-Infeld gravity theory.
NASA Astrophysics Data System (ADS)
Ellis, John; Mavromatos, Nick E.; Nanopoulos, Dimitri V.
2014-11-01
In a recent paper we showed how Starobinsky-like inflation could emerge from dilaton dynamics in brane cosmology scenarios based on string theory, in which our universe is represented as a three-brane and the effective potential acquires a constant term from a density of effectively point-like non-perturbative defects on the brane: ``D-particles''. Here we explore how quantum fluctuations of the ensemble of D-particles during the inflationary period may modify the effective inflationary potential due to the dilaton. We then discuss two specific ways in which an enhanced ratio of tensor to scalar perturbations may arise: via either a condensate of vector fields with a Born-Infeld action that may be due to such recoil fluctuations, or graviton production in the D-particle vacuum.
Matrix flavor brane and dual Wilson line
NASA Astrophysics Data System (ADS)
Karch, Andreas; Sun, Sichun
2014-03-01
We study a novel non-Abelian matrix configuration of probe D-branes in AdS5. This configuration gives rise to a new D-brane phenomenon related to the known "Myers effect" in the context of holography. It is dual to a deformation of the field theory by a Wilson line threaded fermion bilinear. We study the two-point function of these short Wilson lines from both the non-Abelian Dirac-Born-Infeld action and a classical string world sheet calculation and identify the region where they agree. We also study a related configuration where the non-Abelian nature of the embedding functions is enhanced by a background flux as in the Myers effect.
Zhang, Qing; Huang, Yong-Chang
2011-11-01
We derive a Dirac-Born-Infeld (DBI) potential and DBI inflation action by rescaling the metric. The determinant of the induced metric naturally includes the kinetic energy and the potential energy. In particular, the potential energy and kinetic energy can convert into each other in any order, which is in agreement with the limit of classical physics. This is quite different from the usual DBI action. We show that the Taylor expansion of the DBI action can be reduced into the form in the non-linear classical physics. These investigations are the support for the statement that the results of string theory are consistent with quantum mechanics and classical physics. We deduce the Phantom, K-essence, Quintessence and Generalized Klein-Gordon Equation from the DBI model.
Scale invariance and a gravitational model with non-eternal inflation
NASA Astrophysics Data System (ADS)
Herdeiro, Carlos; Hirano, Shinji
2012-05-01
We propose a 3+1 dimensional model of gravity which results in inflation at early times, followed by radiation- and matter-dominated epochs and a subsequent acceleration at late times. Both the inflation and late time acceleration are nearly de Sitter with a large hierarchy between the effective cosmological constants. There is no scalar field agent of inflation, and the transition from the inflation to the radiation-dominated period is smooth. This model is designed so that it yields, at the cost of giving up on Lorentz invariance in the gravitational sector, the Dirac-Born-Infeld type conformal scalar theory when the universe is conformally flat. It, however, resembles Einstein's gravity with the Gibbons-Hawking-York boundary term in weakly curved space-times.
Super jackstraws and super waterwheels
NASA Astrophysics Data System (ADS)
Cho, Jin-Ho
2007-01-01
We construct various new BPS states of D-branes preserving 8 supersymmetries. These include super Jackstraws (a bunch of scattered D- or (p, q)-strings preserving supersymmetries), and super waterwheels (a number of D2-branes intersecting at generic angles on parallel lines while preserving supersymmetries). Super D-Jackstraws are scattered in various dimensions but are dynamical with all their intersections following a common null direction. Meanwhile, super (p, q)-Jackstraws form a planar static configuration. We show that the SO(2) subgroup of SL(2, R), the group of classical S-duality transformations in IIB theory, can be used to generate this latter configuration of variously charged (p, q)-strings intersecting at various angles. The waterwheel configuration of D2-branes preserves 8 supersymmetries as long as the `critical' Born-Infeld electric fields are along the common direction.
Remarks on nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Gaete, Patricio; Helayël-Neto, José
2014-11-01
We consider both generalized Born-Infeld and exponential electrodynamics. The field energy of a point-like charge is finite only for Born-Infeld-like electrodynamics. However, both Born-Infeld-type and exponential electrodynamics display the vacuum birefringence phenomenon. Subsequently, we calculate the lowest-order modifications to the interaction energy for both classes of electrodynamics, within the framework of the gauge-invariant path-dependent variables formalism. These are shown to result in long-range (-type) corrections to the Coulomb potential. Once again, for their noncommutative versions, the interaction energy is ultraviolet finite.
Theory and Vocational Education.
ERIC Educational Resources Information Center
Swanson, Gordon I.
1988-01-01
The search for an explanation of day-to-day problems is the appropriate framework for describing theory. Theory and research have reciprocal relationships: Theory gives direction to research and research refines theory. Vocational education occurs in the context of many theoretical frames. Understanding this theory relatedness is important to…
Decidability of formal theories and hyperincursivity theory
NASA Astrophysics Data System (ADS)
Grappone, Arturo G.
2000-05-01
This paper shows the limits of the Proof Standard Theory (briefly, PST) and gives some ideas of how to build a proof anticipatory theory (briefly, PAT) that has no such limits. Also, this paper considers that Gödel's proof of the undecidability of Principia Mathematica formal theory is not valid for axiomatic theories that use a PAT to build their proofs because the (hyper)incursive functions are self-representable.
NASA Astrophysics Data System (ADS)
Becker, Katrin; Becker, Melanie; Schwarz, John H.
String theory is one of the most exciting and challenging areas of modern theoretical physics. This book guides the reader from the basics of string theory to recent developments. It introduces the basics of perturbative string theory, world-sheet supersymmetry, space-time supersymmetry, conformal field theory and the heterotic string, before describing modern developments, including D-branes, string dualities and M-theory. It then covers string geometry and flux compactifications, applications to cosmology and particle physics, black holes in string theory and M-theory, and the microscopic origin of black-hole entropy. It concludes with Matrix theory, the AdS/CFT duality and its generalizations. This book is ideal for graduate students and researchers in modern string theory, and will make an excellent textbook for a one-year course on string theory. It contains over 120 exercises with solutions, and over 200 homework problems with solutions available on a password protected website for lecturers at www.cambridge.org/9780521860697. Comprehensive coverage of topics from basics of string theory to recent developments Ideal textbook for a one-year course in string theory Includes over 100 exercises with solutions Contains over 200 homework problems with solutions available to lecturers on-line
Foundations for a theory of gravitation theories
NASA Technical Reports Server (NTRS)
Thorne, K. S.; Lee, D. L.; Lightman, A. P.
1972-01-01
A foundation is laid for future analyses of gravitation theories. This foundation is applicable to any theory formulated in terms of geometric objects defined on a 4-dimensional spacetime manifold. The foundation consists of (1) a glossary of fundamental concepts; (2) a theorem that delineates the overlap between Lagrangian-based theories and metric theories; (3) a conjecture (due to Schiff) that the Weak Equivalence Principle implies the Einstein Equivalence Principle; and (4) a plausibility argument supporting this conjecture for the special case of relativistic, Lagrangian-based theories.
ERIC Educational Resources Information Center
Apsche, Jack A.
2005-01-01
In his work on the Theory of Modes, Beck (1996) suggested that there were flaws with his cognitive theory. He suggested that though there are shortcomings to his cognitive theory, there were not similar shortcomings to the practice of Cognitive Therapy. The author suggests that if there are shortcomings to cognitive theory the same shortcomings…
ERIC Educational Resources Information Center
MacLure, Maggie
2010-01-01
Theory frequently offends. The paper argues that this is its strength: the value of theory lies in its power to get in the way. Theory is needed to block the reproduction of banality, and thereby, hopefully, open new possibilities for thinking and doing. However, I also note that theory has become somewhat disengaged from its objects, diminishing…
Quantum Theory is an Information Theory
NASA Astrophysics Data System (ADS)
D'Ariano, Giacomo M.; Perinotti, Paolo
2016-03-01
In this paper we review the general framework of operational probabilistic theories (OPT), along with the six axioms from which quantum theory can be derived. We argue that the OPT framework along with a relaxed version of five of the axioms, define a general information theory. We close the paper with considerations about the role of the observer in an OPT, and the interpretation of the von Neumann postulate and the Schrödinger-cat paradox.
Nonrelativistic superstring theories
Kim, Bom Soo
2007-12-15
We construct a supersymmetric version of the critical nonrelativistic bosonic string theory [B. S. Kim, Phys. Rev. D 76, 106007 (2007).] with its manifest global symmetry. We introduce the anticommuting bc conformal field theory (CFT) which is the super partner of the {beta}{gamma} CFT. The conformal weights of the b and c fields are both 1/2. The action of the fermionic sector can be transformed into that of the relativistic superstring theory. We explicitly quantize the theory with manifest SO(8) symmetry and find that the spectrum is similar to that of type IIB superstring theory. There is one notable difference: the fermions are nonchiral. We further consider noncritical generalizations of the supersymmetric theory using the superspace formulation. There is an infinite range of possible string theories similar to the supercritical string theories. We comment on the connection between the critical nonrelativistic string theory and the lightlike linear dilaton theory.
Teaching Theory X and Theory Y in Organizational Communication
ERIC Educational Resources Information Center
Noland, Carey
2014-01-01
The purpose of the activity described here is to integrate McGregor's Theory X and Theory Y into a group application: design a syllabus that embodies either Theory X or Theory Y tenets. Students should be able to differentiate between Theory X and Theory Y, create a syllabus based on Theory X or Theory Y tenets, evaluate the different syllabi…
Separation-individuation theory and attachment theory.
Blum, Harold P
2004-01-01
Separation-individuation and attachment theories are compared and assessed in the context of psychoanalytic developmental theory and their application to clinical work. As introduced by Margaret Mahler and John Bowlby, respectively, both theories were initially regarded as diverging from traditional views. Separation-individuation theory, though it has had to be corrected in important respects, and attachment theory, despite certain limitations, have nonetheless enriched psychoanalytic thought. Without attachment an infant would die, and with severely insecure attachment is at greater risk for serious disorders. Development depends on continued attachment to a responsive and responsible caregiver. Continued attachment to the primary object was regarded by Mahler as as intrinsic to the process of separation-individuation. Attachment theory does not account for the essential development of separateness, and separation-individuation is important for the promotion of autonomy, independence, and identity. Salient historical and theoretical issues are addressed, including the renewed interest in attachment theory and the related decline of interest in separation-individuation theory. PMID:15222460
Generalizability Theory and Classical Test Theory
ERIC Educational Resources Information Center
Brennan, Robert L.
2011-01-01
Broadly conceived, reliability involves quantifying the consistencies and inconsistencies in observed scores. Generalizability theory, or G theory, is particularly well suited to addressing such matters in that it enables an investigator to quantify and distinguish the sources of inconsistencies in observed scores that arise, or could arise, over…
Equivalency Theory and Distance Education.
ERIC Educational Resources Information Center
Simonson, Michael
1999-01-01
Discusses distance education and the need for an accepted theory. Highlights include theories of independent study; theory of industrialization of teaching; theory of interaction and communication; and equivalency theory that is based on local control, personalized instruction, and telecommunications. (LRW)
[Mathematics and string theory
Jaffe, A.; Yau, Shing-Tung.
1993-01-01
Work on this grant was centered on connections between non- commutative geometry and physics. Topics covered included: cyclic cohomology, non-commutative manifolds, index theory, reflection positivity, space quantization, quantum groups, number theory, etc.
Kheirandish, F.; Amooshahi, M.
2008-11-18
Quantum field theory of a damped vibrating string as the simplest dissipative scalar field theory is investigated by introducing a minimal coupling method. The rate of energy flowing between the system and its environment is obtained.
Theories of Career Development. A Comparison of the Theories.
ERIC Educational Resources Information Center
Osipow, Samuel H.
These seven theories of career development are examined in previous chapters: (1) Roe's personality theory, (2) Holland's career typology theory, (3) the Ginzberg, Ginsburg, Axelrod, and Herma Theory, (4) psychoanalytic conceptions, (5) Super's developmental self-concept theory, (6) other personality theories, and (7) social systems theories.…
ERIC Educational Resources Information Center
Davis, Philip W.
This volume explores objectively the essential characteristic of nine twentieth-century linguistic theories with the theoretical variant for discussion based on one closely representative of work within a given approach or usually associated with the name of the theory. First, the theory of Ferdinand de Saussure is discussed based on his book,…
Constructor theory of probability
2016-01-01
Unitary quantum theory, having no Born Rule, is non-probabilistic. Hence the notorious problem of reconciling it with the unpredictability and appearance of stochasticity in quantum measurements. Generalizing and improving upon the so-called ‘decision-theoretic approach’, I shall recast that problem in the recently proposed constructor theory of information—where quantum theory is represented as one of a class of superinformation theories, which are local, non-probabilistic theories conforming to certain constructor-theoretic conditions. I prove that the unpredictability of measurement outcomes (to which constructor theory gives an exact meaning) necessarily arises in superinformation theories. Then I explain how the appearance of stochasticity in (finitely many) repeated measurements can arise under superinformation theories. And I establish sufficient conditions for a superinformation theory to inform decisions (made under it) as if it were probabilistic, via a Deutsch–Wallace-type argument—thus defining a class of decision-supporting superinformation theories. This broadens the domain of applicability of that argument to cover constructor-theory compliant theories. In addition, in this version some of the argument's assumptions, previously construed as merely decision-theoretic, follow from physical properties expressed by constructor-theoretic principles. PMID:27616914
Testing Theory through Theatrics.
ERIC Educational Resources Information Center
Sellers, Sandra Courtney
2002-01-01
In a nursing theory course, the final exam consists of a role play in which students assume the identity of a theorist they have studied and answer questions in the context of that role. Questions are designed demonstrate their knowledge of major nursing theories and models and the relevance of theory to practice. (SK)
ERIC Educational Resources Information Center
Pais, Alexandre; Valero, Paola
2014-01-01
What is the place of social theory in mathematics education research, and what is it for? This special issue of "Educational Studies in Mathematics" offers insights on what could be the role of some sociological theories in a field that has historically privileged learning theories coming from psychology and mathematics as the main…
Comparing Measurement Theories.
ERIC Educational Resources Information Center
Schumacker, Randall E.
In comparing measurement theories, it is evident that the awareness of the concept of measurement error during the time of Galileo has lead to the formulation of observed scores comprising a true score and error (classical theory), universe score and various random error components (generalizability theory), or individual latent ability and error…
Reflections on Activity Theory
ERIC Educational Resources Information Center
Bakhurst, David
2009-01-01
It is sometimes suggested that activity theory represents the most important legacy of Soviet philosophy and psychology. But what exactly "is" activity theory? The canonical account in the West is given by Engestrom, who identifies three stages in the theory's development: from Vygotsky's insights, through Leontiev's articulation of the…
ERIC Educational Resources Information Center
Peim, Nick
2009-01-01
This paper seeks to re-examine Yrio Engestrom's activity theory as a technology of knowledge designed to enable positive transformations of specific practices. The paper focuses on a key paper where Engestrom defines the nature and present state of activity theory. Beginning with a brief account of the relations between activity theory and…
ERIC Educational Resources Information Center
Missinne, Leo E.; Wilcox, Victoria
This paper discusses the life, theories, and therapeutic techniques of psychotherapist, Viktor E. Frankl. A brief biography of Frankl is included discussing the relationship of his early experiences as a physician to his theory of personality. Frankl's theory focusing on man's need for meaning and emphasizing the spiritual dimension in each human…
La theorie autrement (Theory in Another Light).
ERIC Educational Resources Information Center
Bertocchini, Paola; Costanzo, Edwige
1985-01-01
Outlines a technique using articles from "Le Francais dans le Monde" to teach reading comprehension and theory simultaneously to teachers of French as a second language. Describes a program in Italy using this approach. (MSE)
NASA Technical Reports Server (NTRS)
Owre, Sam; Shankar, Natarajan; Butler, Ricky W. (Technical Monitor)
2001-01-01
The purpose of this task was to provide a mechanism for theory interpretations in a prototype verification system (PVS) so that it is possible to demonstrate the consistency of a theory by exhibiting an interpretation that validates the axioms. The mechanization makes it possible to show that one collection of theories is correctly interpreted by another collection of theories under a user-specified interpretation for the uninterpreted types and constants. A theory instance is generated and imported, while the axiom instances are generated as proof obligations to ensure that the interpretation is valid. Interpretations can be used to show that an implementation is a correct refinement of a specification, that an axiomatically defined specification is consistent, or that a axiomatically defined specification captures its intended models. In addition, the theory parameter mechanism has been extended with a notion of theory as parameter so that a theory instance can be given as an actual parameter to an imported theory. Theory interpretations can thus be used to refine an abstract specification or to demonstrate the consistency of an axiomatic theory. In this report we describe the mechanism in detail. This extension is a part of PVS version 3.0, which will be publicly released in mid-2001.
Zhou, Huan-Xiang
2012-01-01
Some of the rate theories that are most useful for modeling biological processes are reviewed. By delving into some of the details and subtleties in the development of the theories, the review will hopefully help the reader gain a more than superficial perspective. Examples are presented to illustrate how rate theories can be used to generate insight at the microscopic level into biomolecular behaviors. Attempt is made to clear up a number of misconceptions in the literature regarding popular rate theories, including the appearance of Planck’s constant in the transition-state theory and the Smoluchowski result as an upper limit for protein-protein and protein-DNA association rate constants. Future work in combining the implementation of rate theories through computer simulations with experimental probes of rate processes, and in modeling effects of intracellular environments so theories can be used for generating rate constants for systems biology studies is particularly exciting. PMID:20691138
Supersymmetry and String Theory
NASA Astrophysics Data System (ADS)
Dine, Michael
2016-01-01
Preface to the first edition; Preface to the second edition; A note on choice of metric; Text website; Part I. Effective Field Theory: The Standard Model, Supersymmetry, Unification: 1. Before the Standard Model; 2. The Standard Model; 3. Phenomenology of the Standard Model; 4. The Standard Model as an effective field theory; 5. Anomalies, instantons and the strong CP problem; 6. Grand unification; 7. Magnetic monopoles and solitons; 8. Technicolor: a first attempt to explain hierarchies; Part II. Supersymmetry: 9. Supersymmetry; 10. A first look at supersymmetry breaking; 11. The Minimal Supersymmetric Standard Model; 12. Supersymmetric grand unification; 13. Supersymmetric dynamics; 14. Dynamical supersymmetry breaking; 15. Theories with more than four conserved supercharges; 16. More supersymmetric dynamics; 17. An introduction to general relativity; 18. Cosmology; 19. Astroparticle physics and inflation; Part III. String Theory: 20. Introduction; 21. The bosonic string; 22. The superstring; 23. The heterotic string; 24. Effective actions in ten dimensions; 25. Compactification of string theory I. Tori and orbifolds; 26. Compactification of string theory II. Calabi–Yau compactifications; 27. Dynamics of string theory at weak coupling; 28. Beyond weak coupling: non-perturbative string theory; 29. Large and warped extra dimensions; 30. The landscape: a challenge to the naturalness principle; 31. Coda: where are we headed?; Part IV. The Appendices: Appendix A. Two-component spinors; Appendix B. Goldstone's theorem and the pi mesons; Appendix C. Some practice with the path integral in field theory; Appendix D. The beta function in supersymmetric Yang–Mills theory; References; Index.
Gelman, Susan A.; Noles, Nicholaus S.
2013-01-01
Human cognition entails domain-specific cognitive processes that influence memory, attention, categorization, problem-solving, reasoning, and knowledge organization. This review examines domain-specific causal theories, which are of particular interest for permitting an examination of how knowledge structures change over time. We first describe the properties of commonsense theories, and how commonsense theories differ from scientific theories, illustrating with children’s classification of biological and non-biological kinds. We next consider the implications of domain-specificity for broader issues regarding cognitive development and conceptual change. We then examine the extent to which domain-specific theories interact, and how people reconcile competing causal frameworks. Future directions for research include examining how different content domains interact, the nature of theory change, the role of context (including culture, language, and social interaction) in inducing different frameworks, and the neural bases for domain-specific reasoning. PMID:24187603
Generalized higher gauge theory
NASA Astrophysics Data System (ADS)
Ritter, Patricia; Sämann, Christian; Schmidt, Lennart
2016-04-01
We study a generalization of higher gauge theory which makes use of generalized geometry and seems to be closely related to double field theory. The local kinematical data of this theory is captured by morphisms of graded manifolds between the canonical exact Courant Lie 2-algebroid T M ⊕ T ∗ M over some manifold M and a semistrict gauge Lie 2-algebra. We discuss generalized curvatures and infinitesimal gauge transformations. Finite gauge transformation as well as global kinematical data are then obtained from principal 2-bundles over 2-spaces. As dynamical principle, we consider first the canonical Chern-Simons action for such a gauge theory. We then show that a previously proposed 3-Lie algebra model for the six-dimensional (2,0) theory is very naturally interpreted as a generalized higher gauge theory.
Naylor, Ron
2007-03-01
The aim of Galileo's tidal theory was to show that the tides were produced entirely by the earth's motion and thereby to demonstrate the physical truth of Copernicanism. However, in the Dialogue Concerning the Two Chief World Systems Galileo did not explain some of the most significant aspects of the theory completely. As a consequence, the way the theory works has long been disputed. Though there exist a number of interpretations in the literature, the most widely accepted are based on ideas that are not explicitly articulated by Galileo in the Dialogue. This essay attempts to understand the way the theory functions in terms of Galilean physics. It is an interpretation of the theory based solely on Galileo's arguments--and one that reveals it to have had some unrecognized consequences. This interpretation indicates that Galileo's theory would not have worked in the manner he described in the Dialogue. PMID:17539198
Extended theories of gravitation
NASA Astrophysics Data System (ADS)
Fatibene, Lorenzo; Garruto, Simon
2016-04-01
In this paper, we shall review the equivalence between Palatini-f(ℛ) theories and Brans-Dicke (BD) theories at the level of action principles. We shall define the Helmholtz Lagrangian associated to Palatini-f(ℛ) theory and we will define some transformations which will be useful to recover Einstein frame and BD frame. We shall see an explicit example of matter field and we will discuss how the conformal factor affects the physical quantities.
Theory Modeling and Simulation
Shlachter, Jack
2012-08-23
Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.
Automated Lattice Perturbation Theory
Monahan, Christopher
2014-11-01
I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.
NASA Technical Reports Server (NTRS)
Ostwald, Wolfgang
1988-01-01
A brief summary of the fundamentals of the Linear theory of flotation is given. The theory by no means contradicts the previous Laminar theory or even the thermodynamics (Wark-Siedler), rather it is a refinement of the known Hardy-Langmuir-Harkin conceptions for the case when there are not two phases and phase boundaries, but rather three phases and corresponding phase boundary edges. The appearance of such three-phase boundaries (ore, water, air) is characteristic for modern flotation methods.
Between Theory and Observations
NASA Astrophysics Data System (ADS)
Wepster, Steven
Three great mathematicians dominate the history of lunar theory in the middle of the eighteenth century: Leonhard Euler, Alexis Clairaut, and Jean le Rond d’Alembert. Each of them made a lasting contribution to the theory of celestial mechanics and their results had a broader impact than on lunar theory alone. To name but a few examples, Euler codified the trigonometric functions and pioneered the method of variation of orbital constants; Clairaut solved the arduous problem of the motion of the lunar apogee, thereby dealing a decisive blow to the sceptics of Newton’s law of gravitation; and d’Alembert worked out an accurate theory of precession and nutation.
Lincoln, Don
2014-09-30
The Big Bang is the name of the most respected theory of the creation of the universe. Basically, the theory says that the universe was once smaller and denser and has been expending for eons. One common misconception is that the Big Bang theory says something about the instant that set the expansion into motion, however this isn’t true. In this video, Fermilab’s Dr. Don Lincoln tells about the Big Bang theory and sketches some speculative ideas about what caused the universe to come into existence.
NASA Technical Reports Server (NTRS)
Baird, J. K.
1986-01-01
The Ostwald-ripening theory is deduced and discussed starting from the fundamental principles such as Ising model concept, Mayer cluster expansion, Langer condensation point theory, Ginzburg-Landau free energy, Stillinger cutoff-pair potential, LSW-theory and MLSW-theory. Mathematical intricacies are reduced to an understanding version. Comparison of selected works, from 1949 to 1984, on solution of diffusion equation with and without sink/sources term(s) is presented. Kahlweit's 1980 work and Marqusee-Ross' 1954 work are more emphasized. Odijk and Lekkerkerker's 1985 work on rodlike macromolecules is introduced in order to simulate interested investigators.
ERIC Educational Resources Information Center
Costley, Kevin C.
2006-01-01
University professors teaching pre-service teachers base much of their philosophies on theories. Students often ask "Why do we have theories?" "What is the purpose of theories?" "If we like a theory, do we have to use all of the theory?" The most frequent controversial issue is how to use a particular theory in a practical way. In the quest for…
ERIC Educational Resources Information Center
Skemp, Richard R.
Provided is an examination of the methodology used to study the problems of learning addition and subtraction skills used by developmental researchers. The report has sections on categories of theory and their methodologies, which review: (1) Behaviorist, Neo-Behaviorist and Piagetian Theories; (2) the Behaviorist and Piagetian Paradigms; (3)…
Universality and string theory
NASA Astrophysics Data System (ADS)
Bachlechner, Thomas Christian
The first run at the Large Hadron Collider has deeply challenged conventional notions of naturalness, and CMB polarization experiments are about to open a new window to early universe cosmology. As a compelling candidate for the ultraviolet completion of the standard model, string theory provides a prime opportunity to study both early universe cosmology and particle physics. However, relating low energy observations to ultraviolet physics requires knowledge of the metastable states of string theory through the study of vacua. While it is difficult to directly obtain infrared data from explicit string theory constructions, string theory imposes constraints on low energy physics. The study of ensembles of low energy theories consistent with ultra-violet constraints provides insight on generic features we might expect to occur in string compactifications. In this thesis we present a statistical treatment of vacuum stability and vacuum properties in the context of random supergravity theories motivated by string theory. Early universe cosmology provides another avenue to high energy physics. From the low energy perspective large field inflation is typically considered highly unnatural: the scale relevant for the diameter of flat regions in moduli space is sub-Planckian in regions of perturbative control. To approach this problem, we consider generic Calabi-Yau compactifications of string theory and find that super-Planckian diameters of axion fundamental domains in fact arise generically. We further demonstrate that such super-Planckian flat regions are plausibly consistent with theWeak Gravity Conjecture.
Organization Theory as Ideology.
ERIC Educational Resources Information Center
Greenfield, Thomas B.
The theory that organizations are ideological inventions of the human mind is discussed. Organizational science is described as an ideology which is based upon social concepts and experiences. The main justification for organizational theory is that it attempts to answer why we behave as we do in social organizations. Ways in which ideas and…
ERIC Educational Resources Information Center
Jaeger, Audrey J.; Dunstan, Stephany; Thornton, Courtney; Rockenbach, Alyssa B.; Gayles, Joy G.; Haley, Karen J.
2013-01-01
When making decisions that impact student learning, college educators often consider previous experiences, precedent, common sense, and advice from colleagues. But how often do they consider theory? At a recent state-level educators' meeting, the authors of this article asked 50 student affairs educators about the use of theory in their practice.…
Sexual Murderers' Implicit Theories
ERIC Educational Resources Information Center
Beech, Anthony; Fisher, Dawn; Ward, Tony
2005-01-01
Interviews with 28 sexual murderers were subjected to grounded theory analysis. Five implicit theories (ITs) were identified: dangerous world, male sex drive is uncontrollable, entitlement, women as sexual objects, and women as unknowable. These ITs were found to be identical to those identified in the literature as being present in rapists. The…
ERIC Educational Resources Information Center
Shor, Mikhael
2003-01-01
States making game theory relevant and accessible to students is challenging. Describes the primary goal of GameTheory.net is to provide interactive teaching tools. Indicates the site strives to unite educators from economics, political and computer science, and ecology by providing a repository of lecture notes and tests for courses using…
NASA Technical Reports Server (NTRS)
Iesan, D.
1980-01-01
The development of the theory of thermoelasticity, which examines the interactions between the deformation of elastic media and the thermal field, is traced and the fundamental problems of the theory are presented. Results of recent studies on the subject are presented. Emphasis is primarily on media with generalized anisotropy, or isotropy media. Thermomechanical problems and mathematical formulations and resolutions are included.
Theory and Motivational Psychology.
ERIC Educational Resources Information Center
Atkinson, John W.
Motivational psychology and test theory are compared in this discussion, which focuses on distinguishing the effects of motivation and of ability on test performance and educational achievement. Recent theory in achievement motivation considers the motivational significance of future goals as they affect present activities that are instrumental in…
Catterall, Simon; Hubisz, Jay; Balachandran, Aiyalam; Schechter, Joe
2013-01-05
This final report describes the activities of the high energy theory group at Syracuse University for the period 1 January 2010 through April 30 2013. The research conducted by the group includes lattice gauge theory, non-commutative geometry, phenomenology and mathematical physics.
ERIC Educational Resources Information Center
Skabelund, Donald E.
1974-01-01
Presents an analysis of scientific theory which is applicable to the full range of historical situations. Indicates that theory can be resolved into three generalization levels, one neutral element, and two modes. Included are examples illustrating the constituency of the three levels in two modes. (CC)
Siegel, Allen M
2009-04-01
In "Theory Is Personal," Allen Siegel MD, a Chicago psychoanalyst and Assistant Professor of Clinical Psychiatry at Rush University Medical Center, shares the very personal story of how he came to his theory. Sometimes we find our theory. Other times, Siegel argues, it is our theory that finds us. In this article Siegel catalogues his early encounters with figures--contemporary and real--from Sigmund Freud to influential department chairs to an analyst who would become legendary for introducing a bold new theory into the psychoanalytic canon. Charting key experiences that shaped his adoption of this new approach--a depression in response to his first patient, a clinical treatment with Heinz Kohut, and exposure to others who dared to challenge Freud--Siegel describes the theory that brought both himself and his patients to life. After outlining the principles that guide the new theory and practice known as self psychology, Siegel tells of the empathic ambiance that can now emerge in the consulting room. Finally, he shows how this new theory of human motivation provides not merely a rationale for psychotherapy but an explanatory apparatus for understanding human action in the world beyond the consulting room. He turns to a brief study of aggression and war, as expressed in a 1932 correspondence between Albert Einstein and Sigmund Freud, to illustrate how the understanding of aggression and war changes significantly when empathy is the field's data collecting instrument. PMID:19379249
ERIC Educational Resources Information Center
Mayer, William V.
In this paper the author examines the question of whether evolution is a theory or a dogma. He refutes the contention that there is a monolithic scientific conspiracy to present evolution as dogma and suggests that his own presentation might be more appropriately entitled "Creationism: Theory or Dogma." (PEB)
ERIC Educational Resources Information Center
Roller, Duane H. D.
1981-01-01
Focusing on history of physics, which began about 600 B.C. with the Ionian Greeks and reaching full development within three centuries, suggests that the creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists. (Author/SK)
French Theory's American Adventures
ERIC Educational Resources Information Center
Cusset, Francois
2008-01-01
In this article, the author discusses how it is simply too late to be still speaking about French theory and its role in the intellectual life of the United States today. It seems to many observers that the gap between real-life politics and theory's guerrillas is much too wide already, after 30 years of academic fever, for the two worlds to even…
ERIC Educational Resources Information Center
Rexhepi, Jevdet; Torres, Carlos Alberto
2011-01-01
This paper discusses Critical Theory, a model of theorizing in the field of the political sociology of education. We argue for a "reimagined" Critical Theory to herald an empowering, liberatory education that fosters curiosity and critical thinking, and a means for successful bottom-up, top-down political engagement. We present arguments at a…
ERIC Educational Resources Information Center
Weinberg, Janet H.
1975-01-01
Presented is an explanation of a non-Darwinian theory of evolution based on the premise that functional differences are the result of many small mutations such as the substitution of one amino acid for another in a large protein molecule. A brief overview of Darwinian evolution and other theories are presented. (EB)
Evaluating Conceptual Metaphor Theory
ERIC Educational Resources Information Center
Gibbs, Raymond W., Jr.
2011-01-01
A major revolution in the study of metaphor occurred 30 years ago with the introduction of "conceptual metaphor theory" (CMT). Unlike previous theories of metaphor and metaphorical meaning, CMT proposed that metaphor is not just an aspect of language, but a fundamental part of human thought. Indeed, most metaphorical language arises from…
ERIC Educational Resources Information Center
Minter, Robert L.
2011-01-01
This article addresses the myriad of pedagogical and andragogical issues facing university educators in the student learning process. It briefly explores the proliferation of learning theories in an attempt to develop awareness among faculty who teach at the university/college levels that not all theories of learning apply to the adult learner. In…
NASA Astrophysics Data System (ADS)
Roller, Duane H. D.
1981-03-01
Physics began about 600 B.C. with the Ionian Greeks and reached full development within three centuries. The creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists.
Towards Extended Vantage Theory
ERIC Educational Resources Information Center
Glaz, Adam
2010-01-01
The applicability of Vantage Theory (VT), a model of (colour) categorization, to linguistic data largely depends on the modifications and adaptations of the model for the purpose. An attempt to do so proposed here, called Extended Vantage Theory (EVT), slightly reformulates the VT conception of vantage by capitalizing on some of the entailments of…
NASA Astrophysics Data System (ADS)
Bergshoeff, Eric A.; Hohm, Olaf; Penas, Victor A.; Riccioni, Fabio
2016-06-01
We present the dual formulation of double field theory at the linearized level. This is a classically equivalent theory describing the duals of the dilaton, the Kalb-Ramond field and the graviton in a T-duality or O( D, D) covariant way. In agreement with previous proposals, the resulting theory encodes fields in mixed Young-tableau representations, combining them into an antisymmetric 4-tensor under O( D, D). In contrast to previous proposals, the theory also requires an antisymmetric 2-tensor and a singlet, which are not all pure gauge. The need for these additional fields is analogous to a similar phenomenon for "exotic" dualizations, and we clarify this by comparing with the dualizations of the component fields. We close with some speculative remarks on the significance of these observations for the full non-linear theory yet to be constructed.
NASA Astrophysics Data System (ADS)
Dankova, T. S.; Rosensteel, G.
1998-10-01
Mean field theory has an unexpected group theoretic mathematical foundation. Instead of representation theory which applies to most group theoretic quantum models, Hartree-Fock and Hartree-Fock-Bogoliubov have been formulated in terms of coadjoint orbits for the groups U(n) and O(2n). The general theory of mean fields is formulated for an arbitrary Lie algebra L of fermion operators. The moment map provides the correspondence between the Hilbert space of microscopic wave functions and the dual space L^* of densities. The coadjoint orbits of the group in the dual space are phase spaces on which time-dependent mean field theory is equivalent to a classical Hamiltonian dynamical system. Indeed it forms a finite-dimensional Lax system. The mean field theories for the Elliott SU(3) and symplectic Sp(3,R) algebras are constructed explicitly in the coadjoint orbit framework.
NASA Astrophysics Data System (ADS)
Stewart, I.
1982-02-01
A discussion is presented of catastrophe theory, with attention to the developmental feedback between this field of mathematics and its applications in the physical sciences. Prominent concepts of catastrophe theory are co-dimension, determinacy, unfoldings, and organizing centers. The ways in which these concepts may be used are shown in light of specific applications taken from the literature, and the methods are generalized to areas not yet recognized to be within the purview of catastrophe theory. Note is taken of the philosophical background provided for this body of theory by the topological dynamics concept of structural stability. Catastrophe theory is in conclusion characterized as an important contribution to the understanding of nonlinear phenomena.
Riding on irrelevant operators
De Rham, Claudia; Ribeiro, Raquel H. E-mail: RaquelHRibeiro@case.edu
2014-11-01
We investigate the stability of a class of derivative theories known as P(X) and Galileons against corrections generated by quantum effects. We use an exact renormalisation group approach to argue that these theories are stable under quantum corrections at all loops in regions where the kinetic term is large compared to the strong coupling scale. This is the regime of interest for screening or Vainshtein mechanisms, and in inflationary models that rely on large kinetic terms. Next, we clarify the role played by the symmetries. While symmetries protect the form of the quantum corrections, theories equipped with more symmetries do not necessarily have a broader range of scales for which they are valid. We show this by deriving explicitly the regime of validity of the classical solutions for P(X) theories including Dirac-Born-Infeld (DBI) models, both in generic and for specific background field configurations. Indeed, we find that despite the existence of an additional symmetry, the DBI effective field theory has a regime of validity similar to an arbitrary P(X) theory. We explore the implications of our results for both early and late universe contexts. Conversely, when applied to static and spherical screening mechanisms, we deduce that the regime of validity of typical power-law P(X) theories is much larger than that of DBI.
Dempster-Shafer theory and connections to information theory
NASA Astrophysics Data System (ADS)
Peri, Joseph S. J.
2013-05-01
The Dempster-Shafer theory is founded on probability theory. The entire machinery of probability theory, and that of measure theory, is at one's disposal for the understanding and the extension of the Dempster-Shafer theory. It is well known that information theory is also founded on probability theory. Claude Shannon developed, in the 1940's, the basic concepts of the theory and demonstrated their utility in communications and coding. Shannonian information theory is not, however, the only type of information theory. In the 1960's and 1970's, further developments in this field were made by French and Italian mathematicians. They developed information theory axiomatically, and discovered not only the Wiener- Shannon composition law, but also the hyperbolic law and the Inf-law. The objective of this paper is to demonstrate the mathematical connections between the Dempster Shafer theory and the various types of information theory. A simple engineering example will be used to demonstrate the utility of the concepts.
NASA Astrophysics Data System (ADS)
Bastin, Ted
2009-07-01
List of participants; Preface; Part I. Introduction: 1. The function of the colloquium - editorial; 2. The conceptual problem of quantum theory from the experimentalist's point of view O. R. Frisch; Part II. Niels Bohr and Complementarity: The Place of the Classical Language: 3. The Copenhagen interpretation C. F. von Weizsäcker; 4. On Bohr's views concerning the quantum theory D. Bohm; Part III. The Measurement Problem: 5. Quantal observation in statistical interpretation H. J. Groenewold; 6. Macroscopic physics, quantum mechanics and quantum theory of measurement G. M. Prosperi; 7. Comment on the Daneri-Loinger-Prosperi quantum theory of measurement Jeffrey Bub; 8. The phenomenology of observation and explanation in quantum theory J. H. M. Whiteman; 9. Measurement theory and complex systems M. A. Garstens; Part IV. New Directions within Quantum Theory: What does the Quantum Theoretical Formalism Really Tell Us?: 10. On the role of hidden variables in the fundamental structure of physics D. Bohm; 11. Beyond what? Discussion: space-time order within existing quantum theory C. W. Kilmister; 12. Definability and measurability in quantum theory Yakir Aharonov and Aage Petersen; 13. The bootstrap idea and the foundations of quantum theory Geoffrey F. Chew; Part V. A Fresh Start?: 14. Angular momentum: an approach to combinatorial space-time Roger Penrose; 15. A note on discreteness, phase space and cohomology theory B. J. Hiley; 16. Cohomology of observations R. H. Atkin; 17. The origin of half-integral spin in a discrete physical space Ted Bastin; Part VI. Philosophical Papers: 18. The unity of physics C. F. von Weizsäcker; 19. A philosophical obstacle to the rise of new theories in microphysics Mario Bunge; 20. The incompleteness of quantum mechanics or the emperor's missing clothes H. R. Post; 21. How does a particle get from A to B?; Ted Bastin; 22. Informational generalization of entropy in physics Jerome Rothstein; 23. Can life explain quantum mechanics? H. H
Theory of Multiple Intelligences: Is It a Scientific Theory?
ERIC Educational Resources Information Center
Chen, Jie-Qi
2004-01-01
This essay discusses the status of multiple intelligences (MI) theory as a scientific theory by addressing three issues: the empirical evidence Gardner used to establish MI theory, the methodology he employed to validate MI theory, and the purpose or function of MI theory.
Introduction to string theory and conformal field theory
Belavin, A. A. Tarnopolsky, G. M.
2010-05-15
A concise survey of noncritical string theory and two-dimensional conformal field theory is presented. A detailed derivation of a conformal anomaly and the definition and general properties of conformal field theory are given. Minimal string theory, which is a special version of the theory, is considered. Expressions for the string susceptibility and gravitational dimensions are derived.
Field-theory methods in coagulation theory
Lushnikov, A. A.
2011-08-15
Coagulating systems are systems of chaotically moving particles that collide and coalesce, producing daughter particles of mass equal to the sum of the masses involved in the respective collision event. The present article puts forth basic ideas underlying the application of methods of quantum-field theory to the theory of coagulating systems. Instead of the generally accepted treatment based on the use of a standard kinetic equation that describes the time evolution of concentrations of particles consisting of a preset number of identical objects (monomers in the following), one introduces the probability W(Q, t) to find the system in some state Q at an instant t for a specific rate of transitions between various states. Each state Q is characterized by a set of occupation numbers Q = (n{sub 1}, n{sub 2}, ..., n{sub g}, ...), where n{sub g} is the total number of particles containing precisely g monomers. Thereupon, one introduces the generating functional {Psi} for the probability W(Q, t). The time evolution of {Psi} is described by an equation that is similar to the Schroedinger equation for a one-dimensional Bose field. This equation is solved exactly for transition rates proportional to the product of the masses of colliding particles. It is shown that, within a finite time interval, which is independent of the total mass of the entire system, a giant particle of mass about the mass of the entire system may appear in this system. The particle in question is unobservable in the thermodynamic limit, and this explains the well-known paradox of mass-concentration nonconservation in classical kinetic theory. The theory described in the present article is successfully applied in studying the time evolution of random graphs.
Field-theory methods in coagulation theory
NASA Astrophysics Data System (ADS)
Lushnikov, A. A.
2011-08-01
Coagulating systems are systems of chaotically moving particles that collide and coalesce, producing daughter particles of mass equal to the sum of the masses involved in the respective collision event. The present article puts forth basic ideas underlying the application of methods of quantum-field theory to the theory of coagulating systems. Instead of the generally accepted treatment based on the use of a standard kinetic equation that describes the time evolution of concentrations of particles consisting of a preset number of identical objects (monomers in the following), one introduces the probability W( Q, t) to find the system in some state Q at an instant t for a specific rate of transitions between various states. Each state Q is characterized by a set of occupation numbers Q = { n 1, n 2, ..., n g , ...}, where n g is the total number of particles containing precisely g monomers. Thereupon, one introduces the generating functional Ψ for the probability W( Q, t). The time evolution of Ψ is described by an equation that is similar to the Schrödinger equation for a one-dimensional Bose field. This equation is solved exactly for transition rates proportional to the product of the masses of colliding particles. It is shown that, within a finite time interval, which is independent of the total mass of the entire system, a giant particle of mass about the mass of the entire system may appear in this system. The particle in question is unobservable in the thermodynamic limit, and this explains the well-known paradox of mass-concentration nonconservation in classical kinetic theory. The theory described in the present article is successfully applied in studying the time evolution of random graphs.
NASA Astrophysics Data System (ADS)
Svozil, K.
1995-11-01
Inasmuch as physical theories are formalizable, set theory provides a framework for theoretical physics. Four speculations about the relevance of set theoretical modeling for physics are presented: the role of transcendental set theory (i) in chaos theory, (ii) for paradoxical decompositions of solid three-dimensional objects, (iii) in the theory of effective computability (Church-Turing thesis) related to the possible “solution of supertasks,” and (iv) for weak solutions. Several approaches to set theory and their advantages and disadvatages for physical applications are discussed: Canlorian “naive” (i.e., nonaxiomatic) set theory, contructivism, and operationalism. In the author's opinion, an attitude of “suspended attention” (a term borrowed from psychoanalysis) seems most promising for progress. Physical and set theoretical entities must be operationalized wherever possible. At the same time, physicists should be open to “bizarre” or “mindboggling” new formalisms, which need not be operationalizable or testable at the lime of their creation, but which may successfully lead to novel fields of phenomenology and technology.
Svozil, K.
1995-11-01
Inasmuch as physical theories are formalizable, set theory provides a framework for theoretical physics. Four speculations about the relevance of set theoretical modeling for physics are presented: the role of transcendental set theory (i) in chaos theory, (ii) for paradoxical decompositions of solid three-dimensional objects, (iii) in the theory of effective computability (Church-Turing thesis) related to the possible {open_quotes}solution of supertasks,{close_quotes} and (iv) for weak solutions. Several approaches to set theory and their advantages and disadvantages for physical applications are discussed: Cantorian {open_quotes}naive{close_quotes} (i.e., nonaxiomatic) set theory, contructivism, and operationalism. In the author`s opinion, an attitude, of {open_quotes}suspended attention{close_quotes} (a term borrowed from psychoanalysis) seems most promising for progress. Physical and set theoretical entities must be operationalized wherever possible. At the same time, physicists should be open to {open_quotes}bizarre{close_quotes} or {open_quotes}mindboggling{close_quotes} new formalisms, which need not be operationalizable or testable at the time of their creation, but which may successfully lead to novel fields of phenomenology and technology.
NASA Astrophysics Data System (ADS)
Gaiotto, Davide; Razamat, Shlomo S.
2015-07-01
We construct classes of superconformal theories elements of which are labeled by punctured Riemann surfaces. Degenerations of the surfaces correspond, in some cases, to weak coupling limits. Different classes are labeled by two integers ( N, k). The k = 1 case coincides with A N - 1 theories of class and simple examples of theories with k > 1 are orbifolds of some of the A N - 1 class theories. For the space of theories to be complete in an appropriate sense we find it necessary to conjecture existence of new strongly coupled SCFTs. These SCFTs when coupled to additional matter can be related by dualities to gauge theories. We discuss in detail the A 1 case with k = 2 using the supersymmetric index as our analysis tool. The index of theories in classes with k > 1 can be constructed using eigenfunctions of elliptic quantum mechanical models generalizing the Ruijsenaars-Schneider integrable model. When the elliptic curve of the model degenerates these eigenfunctions become polynomials with coefficients being algebraic expressions in fugacities, generalizing the Macdonald polynomials with rational coefficients appearing when k = 1.
Quaternionic quantum field theory
Adler, S.L.
1985-08-19
We show that a quaternionic quantum field theory can be formulated when the numbers of bosonic and fermionic degrees of freedom are equal and the fermions, as well as the bosons, obey a second-order wave equation. The theory is initially defined in terms of a quaternion-imaginary Lagrangian using the Feynman sum over histories. A Schroedinger equation can be derived from the functional integral, which identifies the quaternion-imaginary quantum Hamiltonian. Conversely, the transformation theory based on this Hamiltonian can be used to rederive the functional-integral formulation.
NASA Technical Reports Server (NTRS)
Zhang, Zhimin; Tomlinson, John; Martin, Clyde
1994-01-01
In this work, the relationship between splines and the control theory has been analyzed. We show that spline functions can be constructed naturally from the control theory. By establishing a framework based on control theory, we provide a simple and systematic way to construct splines. We have constructed the traditional spline functions including the polynomial splines and the classical exponential spline. We have also discovered some new spline functions such as trigonometric splines and the combination of polynomial, exponential and trigonometric splines. The method proposed in this paper is easy to implement. Some numerical experiments are performed to investigate properties of different spline approximations.
CONSTRUCTION OF EDUCATIONAL THEORY MODELS.
ERIC Educational Resources Information Center
MACCIA, ELIZABETH S.; AND OTHERS
THIS STUDY DELINEATED MODELS WHICH HAVE POTENTIAL USE IN GENERATING EDUCATIONAL THEORY. A THEORY MODELS METHOD WAS FORMULATED. BY SELECTING AND ORDERING CONCEPTS FROM OTHER DISCIPLINES, THE INVESTIGATORS FORMULATED SEVEN THEORY MODELS. THE FINAL STEP OF DEVISING EDUCATIONAL THEORY FROM THE THEORY MODELS WAS PERFORMED ONLY TO THE EXTENT REQUIRED TO…
Jones, B.J.T.
1980-01-01
The current status of some theories of galaxy formation that are consistent with the hot big bang origin of the universe is reviewed. In the cosmic turbulence theory, an attempt is made to explain not only the characteristic masses and angular momenta of galaxies, but to describe in detail the spectrum of galaxy clustering problems with regard to the observed abundances of the light elements, a Kolmogorov spectrum of turbulence and the fireball are discussed. Attention is given to a primordial chaotic magnetic field, the comparison between baryon-symmetric cosmologies, the origin of galactic spin and theories starting from isothermal perturbations. Also considered are the dilemma of the initial conditions with respect to the era after 10 to the -4th s, and the pancake theory, in which the planar structures that arise provide a natural explanation for filamentary structures.
Electromagnetic scattering theory
NASA Technical Reports Server (NTRS)
Bird, J. F.; Farrell, R. A.
1986-01-01
Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.
Lyons, A. ); Hawking, S.W. )
1991-12-15
We discuss the wormhole effective interactions in string theory, thought of as a sum over two-dimensional field theories on different world sheets. The effective interactions are calculated in the dilute wormhole approximation,'' initially by considering the Green's functions on higher-genus Riemann surfaces, and then by calculating the effect of a complete basis of wave functions on scattering amplitudes for a surface with a boundary. The sum over wormholes is equivalent to having a world sheet of trivial topology and summing over different space-time and matter-field backgrounds. To leading order these consist of the massless fluctuations, since the tachyon cancels out when a sum is done over different spin structures going through the wormhole. In this way we recover quantized general relativity as an effective theory, from a sum over field theories on higher-genus Riemann surfaces.
ERIC Educational Resources Information Center
Gunter, Helen M.
2013-01-01
This article reports on a seminar by the Critical Educational Policy and Leadership Research Interest Group in June 2012. The article reports on the papers and our engagement with the need to use theory to develop descriptions and understandings.
NASA Astrophysics Data System (ADS)
Cheng, Hsin-Chia; Thaler, Jesse; Wang, Lian-Tao
2006-09-01
Using the language of theory space, i.e. moose models, we develop a unified framework for studying composite Higgs models at the LHC. This framework — denoted little M-theory — is conveniently described by a theoretically consistent three-site moose diagram which implements minimal flavor and isospin violation. By taking different limits of the couplings, one can interpolate between simple group-like and minimal moose-like models with and without T-parity. In this way, little M-theory reveals a large model space for composite Higgs theories. We argue that this framework is suitable as a starting point for a comprehensive study of composite Higgs scenarios. The rich collider phenomenology of this framework is briefly discussed.
NASA Technical Reports Server (NTRS)
Jones, R. T. (Compiler)
1979-01-01
A collection of papers on modern theoretical aerodynamics is presented. Included are theories of incompressible potential flow and research on the aerodynamic forces on wing and wing sections of aircraft and on airship hulls.
DOE R&D Accomplishments Database
Salam, A.
1956-04-01
Lectures with mathematical analysis are given on Dispersion Theory and Causality and Dispersion Relations for Pion-nucleon Scattering. The appendix includes the S-matrix in terms of Heisenberg Operators. (F. S.)
Combining Theory With Practice
ERIC Educational Resources Information Center
Houa, Souen
1975-01-01
Using specific examples, the author discusses how the Chinese educators link theory with practice in order to associate education with the three great revolutionary motive forces--the class struggle, the drive towards productivity, and scientific experimentation. (Author/RM)
Motherhood: a discrepancy theory.
Adams, Mary
2015-01-01
Motherhood is a highly anticipated and positive event for most women. Society has constructed many ideal images of motherhood, giving women standards to live up to, and many times setting them up for disappointment. When this disappointment occurs, an emotional reaction follows, which may be fear, guilt, or shame. However, some women are able to experience this mismatch between an ideal and actual self and adapt with minimal emotional reaction. There was not a nursing theory that described this phenomenon. "Self-Discrepancy: A Theory Relating Self and Affect" (Higgins, 1987), from the psychology discipline provided concepts and definitions that could be used to derive a nursing theory. The derivation resulted in a testable mid-range theory that could have a significant impact on nursing interventions for postpartum mood disorders. PMID:26062291
ERIC Educational Resources Information Center
Werner, Suzanne K.
2003-01-01
Describes a series of activities exploring Leonardo da Vinci's tree theory that are designed to strengthen 8th grade students' data collection and problem solving skills in physical science classes. (KHR)
Ahlén, Olof
2015-12-17
These proceedings from the second Caesar Lattes meeting in Rio de Janeiro 2015 are a brief introduction to how automorphic forms appear in the low energy effective action of maximally supersymmetric string theory. The explicit example of the R{sup 4}-interaction of type IIB string theory in ten dimensions is discussed. Its Fourier expansion is interpreted in terms of perturbative and non-perturbative contributions to the four graviton amplitude.
NASA Astrophysics Data System (ADS)
Ahlén, Olof
2015-12-01
These proceedings from the second Caesar Lattes meeting in Rio de Janeiro 2015 are a brief introduction to how automorphic forms appear in the low energy effective action of maximally supersymmetric string theory. The explicit example of the R4-interaction of type IIB string theory in ten dimensions is discussed. Its Fourier expansion is interpreted in terms of perturbative and non-perturbative contributions to the four graviton amplitude.
Leadership and attachment theory.
Bresnahan, Christopher G; Mitroff, Ian I
2007-09-01
Comments on the six articles contained in the special issue of the American Psychologist (January 2007) devoted to leadership, written by W. Bennis; S. J. Zaccaro; V. H. Vroom and A. G. Yago; B. J. Avolio; R. J. Sternberg; and R. J. Hackman and R. Wageman. The current authors opine that the inclusion of attachment theory in the study of leadership could strengthen leadership theories as a whole. PMID:17874909
Nodal Diffusion & Transport Theory
1992-02-19
DIF3D solves multigroup diffusion theory eigenvalue, adjoint, fixed source, and criticality (concentration, buckling, and dimension search) problems in 1, 2, and 3-space dimensions for orthogonal (rectangular or cylindrical), triangular, and hexagonal geometries. Anisotropic diffusion theory coefficients are permitted. Flux and power density maps by mesh cell and regionwise balance integrals are provided. Although primarily designed for fast reactor problems, upscattering and internal black boundary conditions are also treated.
Krueger, Joachim I
2016-01-01
The theory of group-selected Big God religions is a master narrative of cultural evolution. The evidence is a positive manifold of correlated assumptions and variables. Although provocative, the theory is overly elastic. Its critical ingredient - belief in Big Gods - is neither necessary nor sufficient to account for in-group prosociality and discipline. Four specific issues illustrate this elasticity. PMID:26948734
Leadership styles and theories.
Giltinane, Charlotte Louise
It is useful for healthcare professionals to be able to identify the leadership styles and theories relevant to their nursing practice. Being adept in recognising these styles enables nurses to develop their skills to become better leaders, as well as improving relationships with colleagues and other leaders, who have previously been challenging to work with. This article explores different leadership styles and theories, and explains how they relate to nursing practice. PMID:23905259
Marletto, Chiara
2015-01-01
Neo-Darwinian evolutionary theory explains how the appearance of purposive design in the adaptations of living organisms can have come about without their intentionally being designed. The explanation relies crucially on the possibility of certain physical processes: mainly, gene replication and natural selection. In this paper, I show that for those processes to be possible without the design of biological adaptations being encoded in the laws of physics, those laws must have certain other properties. The theory of what these properties are is not part of evolution theory proper, yet without it the neo-Darwinian theory does not fully achieve its purpose of explaining the appearance of design. To this end, I apply constructor theory's new mode of explanation to express exactly within physics the appearance of design, no-design laws, and the logic of self-reproduction and natural selection. I conclude that self-reproduction, replication and natural selection are possible under no-design laws, the only non-trivial condition being that they allow digital information to be physically instantiated. This has an exact characterization in the constructor theory of information. I also show that under no-design laws an accurate replicator requires the existence of a ‘vehicle’ constituting, together with the replicator, a self-reproducer. PMID:25589566
NASA Astrophysics Data System (ADS)
Detournay, Stéphane; Hartman, Thomas; Hofman, Diego M.
2012-12-01
We study field theories in two spacetime dimensions invariant under a chiral scaling symmetry that acts only on right-movers. The local symmetries include one copy of the Virasoro algebra and a U(1) current algebra. This differs from the two-dimensional conformal group but in some respects is equally powerful in constraining the theory. In particular, the symmetries on a torus lead to modular covariance of the partition function, which is used to derive a universal formula for the asymptotic density of states. For an application we turn to the holographic description of black holes in quantum gravity, motivated by the fact that the symmetries in the near-horizon geometry of any extremal black hole are identical to those of a two-dimensional field theory with chiral scaling. We consider two examples: black holes in warped AdS3 in topologically massive gravity and in string theory. In both cases, the density of states in the two-dimensional field theory reproduces the Bekenstein-Hawking entropy of black holes in the gravity theory.
Theory of hydromagnetic turbulence
NASA Technical Reports Server (NTRS)
Montgomery, D.
1983-01-01
The present state of MHD turbulence theory as a possible solar wind research tool is surveyed. The theory is statistical, and does not make statements about individual events. The ensembles considered typically have individual realizations which differ qualitatively, unlike equilibrium statistical mechanics. Most of the theory deals with highly symmetric situations; most of these symmetries have yet to be tested in the solar wind. The applicability of MHD itself to solar wind parameters is highly questionable; yet it has no competitors, as a potentially comprehensive dynamical description. The purpose of solar wind research require sharper articulation. If they are to understand radial turbulent plasma flows from spheres, laboratory experiments and numerical solution of equations of motion may be cheap alternative to spacecraft. If "real life" information is demanded, multiple spacecraft with variable separation may be necessary to go further. The principal emphasis in the theory so far has been on spectral behavior for spatial covariances in wave number space. There is no respectable theory of these for highly anisotropic situations. A rather slow development of theory acts as a brake on justifiable measurement, at this point.
Manturov, Vassily O
2010-06-29
In this work we study knot theories with a parity property for crossings: every crossing is declared to be even or odd according to a certain preassigned rule. If this rule satisfies a set of simple axioms related to the Reidemeister moves, then certain simple invariants solving the minimality problem can be defined, and invariant maps on the set of knots can be constructed. The most important example of a knot theory with parity is the theory of virtual knots. Using the parity property arising from Gauss diagrams we show that even a gross simplification of the theory of virtual knots, namely, the theory of free knots, admits simple and highly nontrivial invariants. This gives a solution to a problem of Turaev, who conjectured that all free knots are trivial. In this work we show that free knots are generally not invertible, and provide invariants which detect the invertibility of free knots. The passage to ordinary virtual knots allows us to strengthen known invariants (such as the Kauffman bracket) using parity considerations. We also discuss other examples of knot theories with parity. Bibliography: 27 items.
Kline, A David
2006-04-01
The received account of whistleblowing, developed over the last quarter century, is identified with the work of Norman Bowie and Richard DeGeorge. Michael Davis has detailed three anomalies for the received view: the paradoxes of burden, missing harm and failure. In addition, he has proposed an alternative account of whistleblowing, viz., the Complicity Theory. This paper examines the Complicity Theory. The supposed anomalies rest on misunderstandings of the received view or misreadings of model cases of whistleblowing, for example, the Challenger disaster and the Ford Pinto. Nevertheless, the Complicity Theory is important for as in science the contrast with alternative competing accounts often helps us better understand the received view. Several aspects of the received view are reviewed and strengthened through comparison with Complicity Theory, including why whistleblowing needs moral justification. Complicity Theory is also critiqued. The fundamental failure of Complicity Theory is its failure to explain why government and the public encourage and protect whistleblowers despite the possibility of considerable harm to the relevant company in reputation, lost jobs, and lost shareholder value. PMID:16609713
Who Needs Learning Theory Anyway?
ERIC Educational Resources Information Center
Zemke, Ron
2002-01-01
Looks at a variety of learning theories: andragogy, behaviorism, cognitivism, conditions of learning, Gestalt, and social learning. Addresses the difficulty of selecting an appropriate theory for training. (JOW)
Relating theories via renormalization
NASA Astrophysics Data System (ADS)
Kadanoff, Leo P.
2013-02-01
The renormalization method is specifically aimed at connecting theories describing physical processes at different length scales and thereby connecting different theories in the physical sciences. The renormalization method used today is the outgrowth of 150 years of scientific study of thermal physics and phase transitions. Different phases of matter show qualitatively different behaviors separated by abrupt phase transitions. These qualitative differences seem to be present in experimentally observed condensed-matter systems. However, the "extended singularity theorem" in statistical mechanics shows that sharp changes can only occur in infinitely large systems. Abrupt changes from one phase to another are signaled by fluctuations that show correlation over infinitely long distances, and are measured by correlation functions that show algebraic decay as well as various kinds of singularities and infinities in thermodynamic derivatives and in measured system parameters. Renormalization methods were first developed in field theory to get around difficulties caused by apparent divergences at both small and large scales. However, no renormalization gives a fully satisfactory formulation of field theory. The renormalization (semi-)group theory of phase transitions was put together by Kenneth G. Wilson in 1971 based upon ideas of scaling and universality developed earlier in the context of phase transitions and of couplings dependent upon spatial scale coming from field theory. Correlations among regions with fluctuations in their order underlie renormalization ideas. Wilson's theory is the first approach to phase transitions to agree with the extended singularity theorem. Some of the history of the study of these correlations and singularities is recounted, along with the history of renormalization and related concepts of scaling and universality. Applications, particularly to condensed-matter physics and particle physics, are summarized. This note is partially a
NASA Astrophysics Data System (ADS)
Akhmeteli, Andrey
2013-03-01
Is it possible to offer a ``no drama'' quantum theory? Something as simple (in principle) as classical electrodynamics - a theory described by a system of partial differential equations (PDE) in 3+1 dimensions, but reproducing unitary evolution of a quantum field theory in the Fock space? The following results suggest an affirmative answer: 1. The scalar field can be algebraically eliminated from scalar electrodynamics; the resulting equations describe independent evolution of the electromagnetic field (EMF). 2. After introduction of a complex 4-potential (producing the same EMF as the standard real 4-potential), the spinor field can be algebraically eliminated from spinor electrodynamics; the resulting equations describe independent evolution of EMF. 3. The resulting theories for EMF can be embedded into quantum field theories. Another fundamental result: in a general case, the Dirac equation is equivalent to a 4th order PDE for just one component, which can be made real by a gauge transform. Issues related to the Bell theorem are discussed. A. Akhmeteli, Int'l Journal of Quantum Information, Vol. 9, Suppl., 17-26 (2011) A. Akhmeteli, Journal of Mathematical Physics, Vol. 52, 082303 (2011) A. Akhmeteli, quant-ph/1111.4630 A. Akhmeteli, J. Phys.: Conf. Ser., Vol. 361, 012037 (2012)
NASA Astrophysics Data System (ADS)
Akhmeteli, Andrey
2012-02-01
Is it possible to offer a ``no drama'' quantum theory? Something as simple (in principle) as classical electrodynamics - a theory described by a system of partial differential equations (PDE) in 3+1 dimensions, but reproducing unitary evolution of a quantum field theory in the configuration space? The following results suggest an affirmative answer: 1. The scalar field can be algebraically eliminated from scalar electrodynamics; the resulting equations describe independent evolution of the electromagnetic field (EMF). 2. After introduction of a complex 4-potential (producing the same EMF as the standard real 4-potential), the spinor field can be algebraically eliminated from spinor electrodynamics; the resulting equations describe independent evolution of EMF. 3. The resulting theories for EMF can be embedded into quantum field theories. Another fundamental result: in a general case, the Dirac equation is equivalent to a 4th order PDE for just one component, which can be made real by a gauge transform. Issues related to the Bell theorem are discussed. A. Akhmeteli, Int'l Journal of Quantum Information, Vol. 9, Suppl., 17-26 (2011) A. Akhmeteli, Journal of Mathematical Physics, Vol. 52, 082303 (2011) A. Akhmeteli, quant-ph/1108.1588
NASA Astrophysics Data System (ADS)
Akhmeteli, Andrey
2012-05-01
Is it possible to offer a "no drama" quantum theory? Something as simple (in principle) as classical electrodynamics - a theory described by a system of partial differential equations in 3+1 dimensions, but reproducing unitary evolution of a quantum field theory in the configuration space? The following results suggest an affirmative answer: 1. The scalar field can be algebraically eliminated from scalar electrodynamics; the resulting equations describe independent evolution of the electromagnetic field. 2. After introduction of a complex 4-potential (producing the same electromagnetic field as the standard real 4-potential), the spinor field can be algebraically eliminated from spinor electrodynamics; the resulting equations describe independent evolution of the electromagnetic field. 3. The resulting theories for the electromagnetic field can be embedded into quantum field theories. Another fundamental result: in a general case, the Dirac equation is equivalent to a 4th order partial differential equations for just one component, which can be made real by a gauge transform. Issues related to the Bell theorem are discussed.
Beyond generalized Proca theories
NASA Astrophysics Data System (ADS)
Heisenberg, Lavinia; Kase, Ryotaro; Tsujikawa, Shinji
2016-09-01
We consider higher-order derivative interactions beyond second-order generalized Proca theories that propagate only the three desired polarizations of a massive vector field besides the two tensor polarizations from gravity. These new interactions follow the similar construction criteria to those arising in the extension of scalar-tensor Horndeski theories to Gleyzes-Langlois-Piazza-Vernizzi (GLPV) theories. On the isotropic cosmological background, we show the existence of a constraint with a vanishing Hamiltonian that removes the would-be Ostrogradski ghost. We study the behavior of linear perturbations on top of the isotropic cosmological background in the presence of a matter perfect fluid and find the same number of propagating degrees of freedom as in generalized Proca theories (two tensor polarizations, two transverse vector modes, and two scalar modes). Moreover, we obtain the conditions for the avoidance of ghosts and Laplacian instabilities of tensor, vector, and scalar perturbations. We observe key differences in the scalar sound speed, which is mixed with the matter sound speed outside the domain of generalized Proca theories.
NASA Astrophysics Data System (ADS)
Tiburzi, Brian C.
The era of high-precision lattice QCD has led to synergy between lattice computations and phenomenological input from chiral perturbation theory. We provide an introduction to chiral perturbation theory with a bent towards understanding properties of the nucleon and other low-lying baryons. Four main topics are the basis for this chapter. We begin with a discussion of broken symmetries and the procedure to construct the chiral Lagrangian. The second topic concerns specialized applications of chiral perturbation theory tailored to lattice QCD, such as partial quenching, lattice discretization, and finite-volume effects. We describe inclusion of the nucleon in chiral perturbation theory using a heavy-fermion Euclidean action. Issues of convergence are taken up as our final topic. We consider expansions in powers of the strange-quark mass, and the appearance of unphysical singularities in the heavy-particle formulation. Our aim is to guide lattice practitioners in understanding the predictions chiral perturbation theory makes for baryons, and show how the lattice will play a role in testing the rigor of the chiral expansion at physical values of the quark masses.
Generalized teleparallel theory
NASA Astrophysics Data System (ADS)
Junior, Ednaldo L. B.; Rodrigues, Manuel E.
2016-07-01
We construct a theory in which the gravitational interaction is described only by torsion, but that generalizes the teleparallel theory still keeping the invariance of local Lorentz transformations in one particular case. We show that our theory falls, in a certain limit of a real parameter, under f(bar{R}) gravity or, in another limit of the same real parameter, under modified f( T) gravity; on interpolating between these two theories it still can fall under several other theories. We explicitly show the equivalence with f(bar{R}) gravity for the cases of a Friedmann-Lemaître-Robertson-Walker flat metric for diagonal tetrads, and a metric with spherical symmetry for diagonal and non-diagonal tetrads. We study four applications, one in the reconstruction of the de Sitter universe cosmological model, for obtaining a static spherically symmetric solution of de Sitter type for a perfect fluid, for evolution of the state parameter ω _{DE}, and for the thermodynamics of the apparent horizon.
NASA Astrophysics Data System (ADS)
Modesto, Leonardo; Piva, Marco; Rachwał, Lesław
2016-07-01
We explicitly compute the one-loop exact beta function for a nonlocal extension of the standard gauge theory, in particular, Yang-Mills and QED. The theory, made of a weakly nonlocal kinetic term and a local potential of the gauge field, is unitary (ghost-free) and perturbatively super-renormalizable. Moreover, in the action we can always choose the potential (consisting of one "killer operator") to make zero the beta function of the running gauge coupling constant. The outcome is a UV finite theory for any gauge interaction. Our calculations are done in D =4 , but the results can be generalized to even or odd spacetime dimensions. We compute the contribution to the beta function from two different killer operators by using two independent techniques, namely, the Feynman diagrams and the Barvinsky-Vilkovisky traces. By making the theories finite, we are able to solve also the Landau pole problems, in particular, in QED. Without any potential, the beta function of the one-loop super-renormalizable theory shows a universal Landau pole in the running coupling constant in the ultraviolet regime (UV), regardless of the specific higher-derivative structure. However, the dressed propagator shows neither the Landau pole in the UV nor the singularities in the infrared regime (IR).
Astronomy and political theory
NASA Astrophysics Data System (ADS)
Campion, Nicholas
2011-06-01
This paper will argue that astronomical models have long been applied to political theory, from the use of the Sun as a symbol of the emperor in Rome to the application of Copernican theory to the needs of absolute monarchy. We will begin with consideration of astral divination (the use of astronomy to ascertain divine intentions) in the ancient Near East. Particular attention will be paid to the use of Newton's discovery that the universe operates according to a single set of laws in order to support concepts of political quality and eighteenth century Natural Rights theory. We will conclude with consideration of arguments that the discovery of the expanding, multi-galaxy universe, stimulated political uncertainty in the 1930s, and that photographs of the Earth from Apollo spacecraft encouraged concepts of the `global village'.
NASA Astrophysics Data System (ADS)
Wiesel, William E.; Pohlen, David J.
1994-01-01
Classical Floquet theory is reviewed with careful attention to the case of repeated eigenvalues common in Hamiltonian systems. Floquet theory generates a canonical transformation to modal variables if the periodic matrix can be made symplectic at the initial time. It is shown that this symplectic normalization can always be carried out, again with careful attention to the degenerate case. The periodic modal vectors and canonical modal variables can always be chosen to be purely real. It is possible to introduce real valued action-angle variables for all modes. Physical interpretation of the canonical degenerate normal modal variables are offered. Finally, it is shown that this transformation enables canonical perturbation theory to be carried out using Floquet modal variables.
Supersymmetric Quantum Field Theories
NASA Astrophysics Data System (ADS)
Grigore, D. R.
2005-03-01
We consider some supersymmetric multiplets in a purely quantum framework. A crucial point is to ensure the positivity of the scalar product in the Hilbert space of the quantum system. For the vector multiplet we obtain some discrepancies with respect to the literature in the expression of the super-propagator and we prove that the model is consistent only for positive mass. The gauge structure is constructed purely deductive and leads to the necessity of introducing scalar ghost superfields, in analogy to the usual gauge theories. Then we consider a supersymmetric extension of quantum gauge theory based on a vector multiplet containing supersymmetric partners of spin 3/2 for the vector fields. As an application we consider the supersymmetric electroweak theory. The resulting self-couplings of the gauge bosons agree with the standard model up to a divergence.
NASA Astrophysics Data System (ADS)
Schmaltz, Martin; Tucker-Smith, David
2005-12-01
Recently there has been renewed interest in the possibility that the Higgs particle of the Standard Model is a pseudo-Nambu-Goldstone boson. This development was spurred by the observation that if certain global symmetries are broken only by the interplay between two or more coupling constants, then the Higgs mass-squared is free from quadratic divergences at one loop. This collective symmetry breaking is the essential ingredient in little Higgs theories, which are weakly coupled extensions of the Standard Model with little or no fine tuning, describing physics up to an energy scale 10 TeV. Here we give a pedagogical introduction to little Higgs theories. We review their structure and phenomenology, focusing mainly on the SU(3) theory, the Minimal Moose, and the littlest Higgs as concrete examples.
Palenik, Mark C.; Dunlap, Brett I.
2015-07-28
Despite the fundamental importance of electron density in density functional theory, perturbations are still usually dealt with using Hartree-Fock-like orbital equations known as coupled-perturbed Kohn-Sham (CPKS). As an alternative, we develop a perturbation theory that solves for the perturbed density directly, removing the need for CPKS. This replaces CPKS with a true Hohenberg-Kohn density perturbation theory. In CPKS, the perturbed density is found in the basis of products of occupied and virtual orbitals, which becomes ever more over-complete as the size of the orbital basis set increases. In our method, the perturbation to the density is expanded in terms of a series of density basis functions and found directly. It is possible to solve for the density in such a way that it makes the total energy stationary even if the density basis is incomplete.
Chen, Jun
2011-10-01
The concept of pain has remained a topic of long debate since its emergence in ancient times. The initial ideas of pain were formulated in both the East and the West before 1800. Since 1800, due to the development of experimental sciences, different theories of pain have emerged and become central topics of debate. However, the existing theories of pain may be appropriate for the interpretation of some aspects of pain, but are not yet comprehensive. The history of pain problems is as long as that of human beings; however, the understanding of pain mechanisms is still far from sufficient. Thus, intensive research is required. This historical review mainly focuses on the development of pain theories and the fundamental discoveries in this field. Other historical events associated with pain therapies and remedies are beyond the scope of this review. PMID:21934730
Allmark, Peter
2003-04-01
Science seems to develop by inducing new knowledge from observation. However, it is hard to find a rational justification for induction. Popper offers one attempt to resolve this problem. Nursing theorists have tended to ignore or reject Popper, often on the false belief that he is a logical positivist (and hence hostile to qualitative research). Logical positivism claims that meaningful sentences containing any empirical content should ultimately be reducible to simple, observation statements. Popper refutes positivism by showing that there are no such simple statements. He is not a positivist. For Popper, the scientist begins with problems and puts forward trial solutions. These are subjected to rigorous testing aimed at falsifying them. A new theoretical position is then reached in which the scientist knows either that the trial solutions are false or that they have not yet been falsified. Science is characterized by the fact that it tests its ideas through attempted falsification. Non-science tests its ideas through attempted refutation. Nursing theory is a mixture of science and non-science. Popper's method requires rigorous testing of theory in both realms. As such, some nursing theory should be discarded. Popper's view faces at least two important criticisms. One is that a scientist can always reject an apparent falsification by instead altering some auxiliary hypothesis (e.g. denying the accuracy of the falsifying observation). Popper can deal with this argument by saying that defence of a theory in this way will eventually break down if the theory is false. The second criticism is that Popper's method does ultimately draw upon induction. This criticism is true, but his method can be usefully adapted. An adapted from of Popper's philosophy of science provides a good basis for nursing theory. PMID:14498963
Kachru, Shamit; McAllister, Liam; Sundrum, Raman
2007-04-04
We study sequestering, a prerequisite for flavor-blind supersymmetry breaking in several high-scale mediation mechanisms, in compactifications of type IIB string theory. We find that although sequestering is typically absent in unwarped backgrounds, strongly warped compactifications do readily sequester. The AdS/CFT dual description in terms of conformal sequestering plays an important role in our analysis, and we establish how sequestering works both on the gravity side and on the gauge theory side. We pay special attention to subtle compactification effects that can disrupt sequestering. Our result is a step toward realizing an appealing pattern of soft terms in a KKLT compactification.
Balatsky, A.V.; Scalapino, D.; Wilkins, J.; Pines, D.; Bedell, K.; Schrieffer, J.R.; Fisk, Z.
1998-12-01
This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have obtained a description of symmetry of the order parameter and pairing state in high-Tc superconductors. They developed a theory of ferromagnetic instability of Fermi-liquid. They have conducted an experimental investigation of the intermetallic compounds and Zintl-type compound. They investigated the properties of Cu-0 ladders. They have developed the theory of liftshitz tails in superconductors. They have conducted a number of summer workshops.
Diagrammatic semiclassical laser theory
Zaitsev, Oleg; Deych, Lev
2010-02-15
We derive semiclassical laser equations valid in all orders of nonlinearity. With the help of a diagrammatic representation, the perturbation series in powers of electric field can be resummed in terms of a certain class of diagrams. The resummation makes it possible to take into account a weak effect of population pulsations in a controlled way while treating the nonlinearity exactly. The proposed laser theory reproduces the all-order nonlinear equations in the approximation of constant population inversion and the third-order equations with population-pulsation terms as special cases. The theory can be applied to arbitrarily open and irregular lasers, such as random lasers.
Delbruck, C; Raffelhuschen, B
1993-09-01
"The present and expected migration flows in Europe require a detailed analysis of determinants and elements of migration decisions. This survey encompasses a view on classical--labor market and demand side oriented--theories, the more recent human capital approach as well as on migration under asymmetric information. Since these theories so far yield an unsatisfactory basis for description and forecasting of multilateral migration flows, a closer look at empirical methods of migration research is taken. Consequently, a description of possible policy oriented applications of the gravity model and the random utility approach, with their descriptive and normative characteristics, is given." (SUMMARY IN ENG) PMID:12319309
NASA Astrophysics Data System (ADS)
Clarke, C. J.; Pringle, J. E.
2004-07-01
We show how the viscous evolution of Keplerian accretion discs can be understood in terms of simple kinetic theory. Although standard physics texts give a simple derivation of momentum transfer in a linear shear flow using kinetic theory, many authors, as detailed by Hayashi & Matsuda, have had difficulties applying the same considerations to a circular shear flow. We show here how this may be done, and note that the essential ingredients are to take proper account of, first, isotropy locally in the frame of the fluid and, secondly, the geometry of the mean flow.
Walsh, Timothy Francis; Reese, Garth M.; Bhardwaj, Manoj Kumar
2004-08-01
This manual describes the theory behind many of the constructs in Salinas. For a more detailed description of how to use Salinas , we refer the reader to Salinas, User's Notes. Many of the constructs in Salinas are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Salinas are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programer-notes manual, the user's notes and of course the material in the open literature.
Holographic effective field theories
NASA Astrophysics Data System (ADS)
Martucci, Luca; Zaffaroni, Alberto
2016-06-01
We derive the four-dimensional low-energy effective field theory governing the moduli space of strongly coupled superconformal quiver gauge theories associated with D3-branes at Calabi-Yau conical singularities in the holographic regime of validity. We use the dual supergravity description provided by warped resolved conical geometries with mobile D3-branes. Information on the baryonic directions of the moduli space is also obtained by using wrapped Euclidean D3-branes. We illustrate our general results by discussing in detail their application to the Klebanov-Witten model.
NASA Astrophysics Data System (ADS)
Jejjala, Vishnu; Minic, Djordje; Ng, Y. Jack; Tze, Chia-Hsiung
We propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov scalings in 2+1 dimensions. This string theory of turbulence should be understood in light of the AdS/CFT dictionary. Our argument is crucially based on the use of Migdal's loop variables and the self-consistent solutions of Migdal's loop equations for turbulence. In particular, there is an area law for turbulence in 2+1 dimensions related to the Kraichnan scaling.
Baryon chiral perturbation theory
NASA Astrophysics Data System (ADS)
Scherer, S.
2012-03-01
We provide a short introduction to the one-nucleon sector of chiral perturbation theory and address the issue of power counting and renormalization. We discuss the infrared regularization and the extended on-mass-shell scheme. Both allow for the inclusion of further degrees of freedom beyond pions and nucleons and the application to higher-loop calculations. As applications we consider the chiral expansion of the nucleon mass to order Script O(q6) and the inclusion of vector and axial-vector mesons in the calculation of nucleon form factors. Finally, we address the complex-mass scheme for describing unstable particles in effective field theory.
Chris Quigg
2001-08-10
After a short essay on the current state of particle physics, the author reviews the antecedents of the modern picture of the weak and electromagnetic interactions and then undertakes a brief survey of the SU(2){sub L} {circle_times} U(1){sub Y} electroweak theory. The authors reviews the features of electroweak phenomenology at tree level and beyond, presents an introduction to the Higgs boson and the 1-TeV scale, and examines arguments for enlarging the electroweak theory. The author concludes with a brief look at low-scale gravity.
Turner, H.
1996-12-31
This paper presents mathematical results that can sometimes be used to simplify the task of reasoning about a default theory, by {open_quotes}splitting it into parts.{close_quotes} These so-called Splitting Theorems for default logic are related in spirit to {open_quotes}partial evaluation{close_quotes} in logic programming, in which results obtained from one part of a program are used to simplify the remainder of the program. In this paper we focus primarily on the statement and proof of the Splitting Theorems for default logic. We illustrate the usefulness of the results by applying them to an example default theory for commonsense reasoning about action.
Perspective: Nonadiabatic dynamics theory
NASA Astrophysics Data System (ADS)
Tully, John C.
2012-12-01
Nonadiabatic dynamics—nuclear motion evolving on multiple potential energy surfaces—has captivated the interest of chemists for decades. Exciting advances in experimentation and theory have combined to greatly enhance our understanding of the rates and pathways of nonadiabatic chemical transformations. Nevertheless, there is a growing urgency for further development of theories that are practical and yet capable of reliable predictions, driven by fields such as solar energy, interstellar and atmospheric chemistry, photochemistry, vision, single molecule electronics, radiation damage, and many more. This Perspective examines the most significant theoretical and computational obstacles to achieving this goal, and suggests some possible strategies that may prove fruitful.
Dempster-Shafer theory and connections to Choquet's theory of capacities and information theory
NASA Astrophysics Data System (ADS)
Peri, Joseph S. J.
2014-06-01
The axiomatic development of information theory, during the 1960's, led to the discovery of various composition laws. The Wiener-Shannon law is well understood, but the Inf law holds particular interest because it creates a connection with the Dempster-Shafer theory. Proceeding along these lines, in a previous paper, I demonstrated the connection between the Dempster-Shafer theory and Information theory. In 1954, Gustave Choquet developed the theory of capacities in connection with potential theory. The basic concepts of capacity theory arise from electrostatics, but a capacity is a generalization of the concept of measure in Analysis. It is well known that Belief and Plausibility in the Dempster-Shafer theory are Choquet capacities. However, it is not well known that the inverse of an information measure is a Choquet capacity. The objective of this paper is to demonstrate the connections among the Dempster- Shafer theory, Information theory and Choquet's theory of capacities.
New insights on the matter-gravity coupling paradigm.
Delsate, Térence; Steinhoff, Jan
2012-07-13
The coupling between matter and gravity in general relativity is given by a proportionality relation between the stress tensor and the geometry. This is an oriented assumption driven by the fact that both the stress tensor and the Einstein tensor are divergenceless. However, general relativity is in essence a nonlinear theory, so there is no obvious reason why the coupling to matter should be linear. On another hand, modified theories of gravity usually affect the vacuum dynamics, yet keep the coupling to matter linear. In this Letter, we address the implications of consistent nonlinear gravity-matter coupling. The Eddington-inspired Born-Infeld theory recently introduced by Bañados and Ferreira provides an enlightening realization of such coupling modifications. We find that this theory coupled to a perfect fluid reduces to general relativity coupled to a nonlinearly modified perfect fluid, leading to an ambiguity between modified coupling and modified equation of state. We discuss observational consequences of this degeneracy and argue that such a completion of general relativity is viable from both an experimental and theoretical point of view through energy conditions, consistency, and singularity-avoidance perspectives. We use these results to discuss the impact of changing the coupling paradigm. PMID:23030149
NASA Astrophysics Data System (ADS)
Herdeiro, Carlos; Hirano, Shinji; Sato, Yuki
2011-12-01
n-DBI gravity is a gravitational theory introduced in [C. Herdeiro and S. Hirano, arXiv:1109.1468.], motivated by Dirac-Born-Infeld type conformal scalar theory and designed to yield noneternal inflation spontaneously. It contains a foliation structure provided by an everywhere timelike vector field n, which couples to the gravitational sector of the theory, but decouples in the small curvature limit. We show that any solution of Einstein gravity with a particular curvature property is a solution of n-DBI gravity. Among them is a class of geometries isometric to a Reissner-Nordström-(anti)-de Sitter black hole, which is obtained within the spherically symmetric solutions of n-DBI gravity minimally coupled to the Maxwell field. These solutions have, however, two distinct features from their Einstein gravity counterparts: (1) the cosmological constant appears as an integration constant and can be positive, negative, or vanishing, making it a variable quantity of the theory; and (2) there is a nonuniqueness of solutions with the same total mass, charge, and effective cosmological constant. Such inequivalent solutions cannot be mapped to each other by a foliation preserving diffeomorphism. Physically they are distinguished by the expansion and shear of the congruence tangent to n, which define scalar invariants on each leaf of the foliation.
Scalar speed limits and cosmology: Acceleration from D-cceleration
NASA Astrophysics Data System (ADS)
Silverstein, Eva; Tong, David
2004-11-01
Causality on the gravity side of the AdS/CFT correspondence restricts motion on the moduli space of the N=4 super Yang-Mills theory by imposing a speed limit on how fast the scalar field may roll. This effect can be traced to higher-derivative operators arising from integrating out light degrees of freedom near the origin. In the strong coupling limit of the theory, the dynamics is well approximated by the Dirac-Born-Infeld Lagrangian for a probe D3-brane moving toward the horizon of the AdS Poincaré patch, combined with an estimate of the (ultimately suppressed) rate of particle and string production in the system. We analyze the motion of a rolling scalar field explicitly in the strong coupling regime of the field theory and extend the analysis to cosmological systems obtained by coupling this type of field theory to four-dimensional gravity. This leads to a mechanism for slow roll inflation for a massive scalar at sub-Planckian vacuum expectation value without need for a flat potential (realizing a version of k inflation in a microphysical framework). It also leads to a variety of novel Friedman-Roberston-Walker cosmologies, some of which are related to those obtained with tachyon matter.
New Insights on the Matter-Gravity Coupling Paradigm
NASA Astrophysics Data System (ADS)
Delsate, Térence; Steinhoff, Jan
2012-07-01
The coupling between matter and gravity in general relativity is given by a proportionality relation between the stress tensor and the geometry. This is an oriented assumption driven by the fact that both the stress tensor and the Einstein tensor are divergenceless. However, general relativity is in essence a nonlinear theory, so there is no obvious reason why the coupling to matter should be linear. On another hand, modified theories of gravity usually affect the vacuum dynamics, yet keep the coupling to matter linear. In this Letter, we address the implications of consistent nonlinear gravity-matter coupling. The Eddington-inspired Born-Infeld theory recently introduced by Bañados and Ferreira provides an enlightening realization of such coupling modifications. We find that this theory coupled to a perfect fluid reduces to general relativity coupled to a nonlinearly modified perfect fluid, leading to an ambiguity between modified coupling and modified equation of state. We discuss observational consequences of this degeneracy and argue that such a completion of general relativity is viable from both an experimental and theoretical point of view through energy conditions, consistency, and singularity-avoidance perspectives. We use these results to discuss the impact of changing the coupling paradigm.
Self Psychology as Feminist Theory.
ERIC Educational Resources Information Center
Gardiner, Judith Kegan
1987-01-01
Although the "self psychology" theories of Heinz Kohut tend to neglect gender, they hold promise for feminist theory because they avoid some problems and limitations of the object-relations theory, especially its conflation of femininity with heterosexuality and apparent closure to historical change. Feminist self-psychology theory, in contrast,…
Theory-Based Stakeholder Evaluation
ERIC Educational Resources Information Center
Hansen, Morten Balle; Vedung, Evert
2010-01-01
This article introduces a new approach to program theory evaluation called theory-based stakeholder evaluation or the TSE model for short. Most theory-based approaches are program theory driven and some are stakeholder oriented as well. Practically, all of the latter fuse the program perceptions of the various stakeholder groups into one unitary…
NASA Technical Reports Server (NTRS)
Ni, W.
1972-01-01
A new relativistic theory of gravity is presented. This theory agrees with all experiments to date. It is a metric theory, it is Lagrangian-based, and it possesses a preferred frame with conformally-flat space slices. With an appropriate choice of certain adjustable functions and parameters, this theory possesses precisely the same post-Newtonian limit as general relativity.
Vector field theories in cosmology
Tartaglia, A.; Radicella, N.
2007-10-15
Recently proposed theories based on the cosmic presence of a vectorial field are compared and contrasted. In particular the so-called Einstein aether theory is discussed in parallel with a recent proposal of a strained space-time theory (cosmic defect theory). We show that the latter fits reasonably well the cosmic observed data with only one, or at most two, adjustable parameters, while other vector theories use much more. The Newtonian limits are also compared. Finally we show that the cosmic defect theory may be considered as a special case of the aether theories, corresponding to a more compact and consistent paradigm.
Intelligence: Theories and Testing.
ERIC Educational Resources Information Center
Papanastasiou, Elena C.
This paper reviews what is known about intelligence and the use of intelligence tests. Environmental and hereditary factors that affect performance on intelligence tests are reviewed, along with various theories that have been proposed about the basis of intelligence. Intelligence tests do not test intelligence per se but make inferences about a…
ERIC Educational Resources Information Center
Kaplan, Sandra N.
2012-01-01
The importance of putting theory into practice can be addressed and advocated to educators and gifted students through the presentation of a Continuum of Practice. Articulating the sequence and phases of practice can underscore how practice can take place; it also can change the perspective and meaning of practice.
Colloquium: Topological band theory
NASA Astrophysics Data System (ADS)
Bansil, A.; Lin, Hsin; Das, Tanmoy
2016-04-01
The first-principles band theory paradigm has been a key player not only in the process of discovering new classes of topologically interesting materials, but also for identifying salient characteristics of topological states, enabling direct and sharpened confrontation between theory and experiment. This review begins by discussing underpinnings of the topological band theory, which involve a layer of analysis and interpretation for assessing topological properties of band structures beyond the standard band theory construct. Methods for evaluating topological invariants are delineated, including crystals without inversion symmetry and interacting systems. The extent to which theoretically predicted properties and protections of topological states have been verified experimentally is discussed, including work on topological crystalline insulators, disorder and interaction driven topological insulators (TIs), topological superconductors, Weyl semimetal phases, and topological phase transitions. Successful strategies for new materials discovery process are outlined. A comprehensive survey of currently predicted 2D and 3D topological materials is provided. This includes binary, ternary, and quaternary compounds, transition metal and f -electron materials, Weyl and 3D Dirac semimetals, complex oxides, organometallics, skutterudites, and antiperovskites. Also included is the emerging area of 2D atomically thin films beyond graphene of various elements and their alloys, functional thin films, multilayer systems, and ultrathin films of 3D TIs, all of which hold exciting promise of wide-ranging applications. This Colloquium concludes by giving a perspective on research directions where further work will broadly benefit the topological materials field.
Children's Theories of Motivation
ERIC Educational Resources Information Center
Gurland, Suzanne T.; Glowacky, Victoria C.
2011-01-01
To investigate children's theories of motivation, we asked 166 children (8-12 years of age) to rate the effect of various motivational strategies on task interest, over the short and long terms, in activities described as appealing or unappealing. Children viewed the rewards strategy as resulting in greatest interest except when implemented over…
Attachment Theory and Mindfulness
ERIC Educational Resources Information Center
Snyder, Rose; Shapiro, Shauna; Treleaven, David
2012-01-01
We initiate a dialog between two central areas in the field of psychology today: attachment theory/research and mindfulness studies. The impact of the early mother-infant relationship on child development has been well established in the literature, with attachment theorists having focused on the correlation between a mother's capacity for…
Shikano, Yutaka
2011-03-28
I show that the weak value theory is useful from the viewpoints of the experimentally verifiability, consistency, capacity for explanation as to many quantum paradoxes, and practical advantages. As an example, the initial state in the Hardy paradox can be experimentally verified using the weak value via the weak measurement.
Barnett, Stephen M.; Cresser, James D.
2005-08-15
We present a Markovian quantum theory of friction. Our approach is based on the idea that collisions between a Brownian particle and single molecules of the surrounding medium constitute, as far as the particle is concerned, instantaneous simultaneous measurements of its position and momentum.
ERIC Educational Resources Information Center
Thornberg, Robert
2012-01-01
There is a widespread idea that in grounded theory (GT) research, the researcher has to delay the literature review until the end of the analysis to avoid contamination--a dictum that might turn educational researchers away from GT. Nevertheless, in this article the author (a) problematizes the dictum of delaying a literature review in classic…
ERIC Educational Resources Information Center
Stewart, Jim; Harte, Victoria; Sambrook, Sally
2011-01-01
Purpose: The aim of the paper is to examine the meaning and value of the notion of theory as a basis for other papers in the special issue which examine facets of theorising HRD. Design/methodology/approach: A small scale and targeted literature review was conducted which focused on writings in the philosophy and sociology of science in order to…
Theories of Modern Management.
ERIC Educational Resources Information Center
Knight, W. Hal
This chapter of "Principles of School Business Management" identifies management theories that provide a fundamental conceptual knowledge base that school business officials can use to understand the school organizational setting and its influences on the day-to-day operation of the educational process. Particular attention is paid to aspects of…
MFIX documentation theory guide
Syamlal, M.; Rogers, W.; O`Brien, T.J.
1993-12-01
This report describes the MFIX (Multiphase Flow with Interphase exchanges) computer model. MFIX is a general-purpose hydrodynamic model that describes chemical reactions and heat transfer in dense or dilute fluid-solids flows, flows typically occurring in energy conversion and chemical processing reactors. MFIX calculations give detailed information on pressure, temperature, composition, and velocity distributions in the reactors. With such information, the engineer can visualize the conditions in the reactor, conduct parametric studies and what-if experiments, and, thereby, assist in the design process. The MFIX model, developed at the Morgantown Energy Technology Center (METC), has the following capabilities: mass and momentum balance equations for gas and multiple solids phases; a gas phase and two solids phase energy equations; an arbitrary number of species balance equations for each of the phases; granular stress equations based on kinetic theory and frictional flow theory; a user-defined chemistry subroutine; three-dimensional Cartesian or cylindrical coordinate systems; nonuniform mesh size; impermeable and semi-permeable internal surfaces; user-friendly input data file; multiple, single-precision, binary, direct-access, output files that minimize disk storage and accelerate data retrieval; and extensive error reporting. This report, which is Volume 1 of the code documentation, describes the hydrodynamic theory used in the model: the conservation equations, constitutive relations, and the initial and boundary conditions. The literature on the hydrodynamic theory is briefly surveyed, and the bases for the different parts of the model are highlighted.
NASA Astrophysics Data System (ADS)
Hoffman, Johan; Jansson, Johan; Johnson, Claes
2016-06-01
We present a new mathematical theory explaining the fluid mechanics of subsonic flight, which is fundamentally different from the existing boundary layer-circulation theory by Prandtl-Kutta-Zhukovsky formed 100 year ago. The new theory is based on our new resolution of d'Alembert's paradox showing that slightly viscous bluff body flow can be viewed as zero-drag/lift potential flow modified by 3d rotational slip separation arising from a specific separation instability of potential flow, into turbulent flow with nonzero drag/lift. For a wing this separation mechanism maintains the large lift of potential flow generated at the leading edge at the price of small drag, resulting in a lift to drag quotient of size 15-20 for a small propeller plane at cruising speed with Reynolds number {Re≈ 107} and a jumbojet at take-off and landing with {Re≈ 108} , which allows flight at affordable power. The new mathematical theory is supported by computed turbulent solutions of the Navier-Stokes equations with a slip boundary condition as a model of observed small skin friction of a turbulent boundary layer always arising for {Re > 106} , in close accordance with experimental observations over the entire range of angle of attacks including stall using a few millions of mesh points for a full wing-body configuration.
ERIC Educational Resources Information Center
Langberg, Arnold
1984-01-01
Describes the individualized program of Mountain Open High School which at first coincidentally resembed Maurice Gibbons'"Walkabout" concept and was subsequently more consciously shaped by theory. Students move through three phases culminating in challenging independent projects of practical use. (MJL)
Variational transition state theory
Truhlar, D.G.
1993-12-01
This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
The theory which asserts that the universe originated a finite time ago by expanding from an infinitely compressed state. According to this model, space, time and matter originated together, and the universe has been expanding ever since. Key stages in the history of the Big Bang universe are summarized below....
NASA Technical Reports Server (NTRS)
Chiu, Huei-Huang
1989-01-01
A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended.
Extended conformal field theories
NASA Astrophysics Data System (ADS)
Taormina, Anne
1990-08-01
Some extended conformal field theories are briefly reviewed. They illustrate how non minimal models of the Virasoro algebra (c≥1) can become minimal with respect to a larger algebra. The accent is put on N-extended superconformal algebras, which are relevant in superstring compactification.
Stupakov, G.; /SLAC
2009-06-05
We review recent progress in the following areas of the impedance theory: calculation of impedance of tapers and small angle collimators; optical approximation and parabolic equation for the high-frequency impedance; impedance due to resistive inserts in a perfectly conducting pipe.
NASA Astrophysics Data System (ADS)
Shandera, Sarah
2015-04-01
I will discuss the importance of measurements or improved constraints of primordial tensor modes for theories of the primordial universe. In particular, I will review the implications of the amplitude of the tensor fluctuations for inflation and discuss what an era of B-mode cosmology could teach us about particle physics near the Planck scale.
NASA Technical Reports Server (NTRS)
Pepe, S.; Pepe, W. D.; Strauss, A. M.
1976-01-01
A general theory of orthodontic motion is developed that can be applied to determine the forces necessary to induce a given tooth to move to the predetermined desirable position. It is assumed that the natural (nonorthodontic) forces may be represented by a periodic function and the orthodontic forces may be superimposed upon the natural forces. A simple expression is derived for the applied stress.
ERIC Educational Resources Information Center
Cooper, Wesley
2003-01-01
James's moral theory, primarily as set out in "The Moral Philosopher and the Moral Life" (in his "The Will To Believe" (1897)), is presented here as having a two-level structure, an empirical or historical level where progress toward greater moral inclusiveness is central, and a metaphysical or end-of-history level--James's "kingdom of…
Apprentice Machine Theory Outline.
ERIC Educational Resources Information Center
Connecticut State Dept. of Education, Hartford. Div. of Vocational-Technical Schools.
This volume contains outlines for 16 courses in machine theory that are designed for machine tool apprentices. Addressed in the individual course outlines are the following topics: basic concepts; lathes; milling machines; drills, saws, and shapers; heat treatment and metallurgy; grinders; quality control; hydraulics and pneumatics;…
Handicapping Social Exchange Theory.
ERIC Educational Resources Information Center
Mishler, Barbara
The economic theory of social exchange has some serious shortcomings when applied to minorities--especially the disabled. First, it assumes dyads comprise the basic unit where exchange occurs and that rewards and costs must occur at that level. Second, the model standardizes the experience of white, Western European and American males. The model…
ERIC Educational Resources Information Center
Braun, Henry I.; Mislevy, Robert
2005-01-01
Many of us have an intuitive understanding of physics that works surprisingly well to guide everyday action, but we would not attempt to send a rocket to the moon with it. Unfortunately, the authors argue, our policy makers are not as cautious when it comes to basing our school accountability system on intuitive test theory. Intuitive physics…
Nonlinear Theory and Breakdown
NASA Technical Reports Server (NTRS)
Smith, Frank
2007-01-01
The main points of recent theoretical and computational studies on boundary-layer transition and turbulence are to be highlighted. The work is based on high Reynolds numbers and attention is drawn to nonlinear interactions, breakdowns and scales. The research focuses in particular on truly nonlinear theories, i.e. those for which the mean-flow profile is completely altered from its original state. There appear to be three such theories dealing with unsteady nonlinear pressure-displacement interactions (I), with vortex/wave interactions (II), and with Euler-scale flows (III). Specific recent findings noted for these three, and in quantitative agreement with experiments, are the following. Nonlinear finite-time break-ups occur in I, leading to sublayer eruption and vortex formation; here the theory agrees with experiments (Nishioka) regarding the first spike. II gives rise to finite-distance blowup of displacement thickness, then interaction and break-up as above; this theory agrees with experiments (Klebanoff, Nishioka) on the formation of three-dimensional streets. III leads to the prediction of turbulent boundary-layer micro-scale, displacement-and stress-sublayer-thicknesses.
ERIC Educational Resources Information Center
Patrick, Amy M.
2010-01-01
This article examines ways in which the fundamentals of both writing studies and sustainability studies overlap and complement each other, ultimately moving toward a theory of writing that not only is sustainable, but that also sustains writing practice across a variety of areas. For example, in order to be sustainable, both writing and…
Evolutionary Theory under Fire.
ERIC Educational Resources Information Center
Lewin, Roger
1980-01-01
Summarizes events of a conference on evolutionary biology in Chicago entitled: "Macroevolution." Reviews the theory of modern synthesis, a term used to explain Darwinism in terms of population biology and genetics. Issues presented at the conference are discussed in detail. (CS)
ERIC Educational Resources Information Center
Marks, Stephen R.
1974-01-01
Durkheim's theory of anomie is traced and argued to be a major development that followed the publication of "Suicide." Recognition of anomie as a macrosociological problem rendered it insoluble by Durkeheim's practical-humanistic orientation. In this connection his remedial proposals -- occupational, political, education, and "creation and…
NASA Astrophysics Data System (ADS)
You, Setthivoine
2015-11-01
A new canonical field theory has been developed to help interpret the interaction between plasma flows and magnetic fields. The theory augments the Lagrangian of general dynamical systems to rigourously demonstrate that canonical helicity transport is valid across single particle, kinetic and fluid regimes, on scales ranging from classical to general relativistic. The Lagrangian is augmented with two extra terms that represent the interaction between the motion of matter and electromagnetic fields. The dynamical equations can then be re-formulated as a canonical form of Maxwell's equations or a canonical form of Ohm's law valid across all non-quantum regimes. The field theory rigourously shows that helicity can be preserved in kinetic regimes and not only fluid regimes, that helicity transfer between species governs the formation of flows or magnetic fields, and that helicity changes little compared to total energy only if density gradients are shallow. The theory suggests a possible interpretation of particle energization partitioning during magnetic reconnection as canonical wave interactions. This work is supported by US DOE Grant DE-SC0010340.
Refiguring Composition through Theory
ERIC Educational Resources Information Center
Lynch-Biniek, Amy
2009-01-01
In this dissertation, I argue that curricular choices in Composition are overdetermined by the academic labor system and its negative effect on the status of composition theory. Despite the growth of disciplinary knowledge, composition programs are still staffed largely with underpaid and under supported faculty and graduate students, many of whom…
(Mathematics and string theory)
Not Available
1992-01-01
Over the past year our research activities concentrated around: (1) non-commutative differential geometry and its connections with quantum physics and (2) 2-dimensional(super) conformal quantum field theories and related non-linear {sigma}-models. This paper discusses these topics.
ERIC Educational Resources Information Center
Parker, Janice
1997-01-01
Presents an easy and inexpensive method to demonstrate VSEPR theory that involves the use of only a ring stand, clamp, cow magnets, and a ball bearing. Has the advantage of producing a series of models using invisible magnetic repulsion forces to show the orientations occurring in molecules where similarly invisible electron repulsion forces are…
Personality Theory and Psychotherapy
ERIC Educational Resources Information Center
Fagan, Joen; And Others
1974-01-01
This group of articles discusses various aspects of Gestalt Therapy including its major contributions, role in psychotherapy, and contributions of Gestalt psychology in general. There is some discussion of the philosophical background of Gestalt therapy along with Gestalt theory of emotion. A case study and an annotated bibliography are included…
ERIC Educational Resources Information Center
Christensen, Paula, Ed.
This document contains the following papers on theory from the SITE (Society for Information Technology & Teacher Education) 2002 conference: (1) "The Emerging Ecological Contribution of Online Resources and Tools to K-12 Classrooms" (Therese Laferriere, Robert Bracewell, Alain Breuleux); (2) "Pedagogical Ethnotechnography: A Bifocal Lens To…
ERIC Educational Resources Information Center
Christensen, Paula, Ed.
This document contains the following papers on theory from the SITE (Society for Information Technology & Teacher Education) 2001 Conference: (1) "IT with Integrity" (Savilla Banister); (2) "Applications of Knowledge Based Evaluation in Educational Technology" (Michael Connell); (3) "A Tutor's Advice Trains a Student's Self-Regulation Skill"…
ERIC Educational Resources Information Center
Al Shalabi, M. Fadi; Nodoushan, Mohammad Ali Salmani
2009-01-01
In this paper, it is argued, based on evidence from psychological literature, that there are three major approaches to the study of personality, namely (a) situationism, (b) interactionism, and (c) constructivism. It is also noticed that these approached have resulted in the emergence of three major types of personality theories: (1) type…
ERIC Educational Resources Information Center
Al Shalabi, M. Fadi; Salmani Nodoushan, Mohammad Ali
2009-01-01
In this paper, it is argued, based on evidence from psychological literature, that there are three major approaches to the study of personality, namely (1) situationism, (2) interactionism, and (3) constructivism. It is also noticed that these approaches have resulted in the emergence of three major types of personality theories: (i) type…
Benchmarking nuclear fission theory
Bertsch, G. F.; Loveland, W.; Nazarewicz, W.; Talou, P.
2015-05-14
We suggest a small set of fission observables to be used as test cases for validation of theoretical calculations. Thus, the purpose is to provide common data to facilitate the comparison of different fission theories and models. The proposed observables are chosen from fission barriers, spontaneous fission lifetimes, fission yield characteristics, and fission isomer excitation energies.
NASA Astrophysics Data System (ADS)
Speck, Jared R.
The two hyperbolic systems of PDEs we consider in this work are the source-free Maxwell-Born-Infeld (MBI) field equations and the Euler-Nordstrom system for gravitationally self-interacting fluids. The former system plays a central role in Kiessling's recently proposed self-consistent model of classical electrodynamics with point charges, a model that does not suffer from the infinities found in the classical Maxwell-Maxwell model with point charges. The latter system is a scalar gravity caricature of the incredibly more complex Euler-Einstein system. The primary original contributions of the thesis can be summarized as follows: (1) We give a sharp non-local criterion for the formation of singularities in plane-symmetric solutions to the source-free MBI field equations. We also use a domain of dependence argument to show that 3-d initial data agreeing with certain plane-symmetric data on a large enough ball lead to solutions that form singularities in finite time. This work is an extension of a theorem of Brenier, who studied singularity formation in periodic plane-symmetric solutions. (2) We prove well-posedness for the Euler-Nordstrom system with a cosmological constant (ENkappa) for initial data that are an HN perturbation (not necessarily small) of a uniform, quiet fluid, for N ≥ 3. The method of proof relies on the framework of energy currents that has been recently developed by Christodoulou. We turn to this method out of necessity: two common frameworks for showing well-posedness in HN, namely symmetric hyperbolicity and strict hyperbolicity, do not apply to the ENkappa system, while Christodoulou's techniques apply to all hyperbolic systems derivable from a Lagrangian, of which the ENkappa system is an example. (3) We insert the speed of light c as a parameter into the ENkappa system (and designate the family of systems ENck ) in order to study the non-relativistic limit c to infinity. Taking the formal limit in the equations gives the Euler
U-duality between NCOS theory and matrix theory
NASA Astrophysics Data System (ADS)
Hyun, Seungjoon
2001-03-01
We show that the NCOS (noncommutative open string) theories on torus T p ( p⩽5) are U-dual to matrix theory on torus with electric flux background. Under U-duality, the number of D-branes and the number of units of electric flux get interchanged. Furthermore, under the same U-duality the decoupling limit taken in the NCOS theory maps to the decoupling limit taken in the matrix theory, thus ensure the U-duality between those two class of theories. We consider the energy needed for Higgsing process and some bound states with finite energy and find agreements in both theories.
Non-Relativistic Superstring Theories
Kim, Bom Soo
2007-12-14
We construct a supersymmetric version of the 'critical' non-relativistic bosonic string theory [1] with its manifest global symmetry. We introduce the anticommuting bc CFT which is the super partner of the {beta}{gamma} CFT. The conformal weights of the b and c fields are both 1/2. The action of the fermionic sector can be transformed into that of the relativistic superstring theory. We explicitly quantize the theory with manifest SO(8) symmetry and find that the spectrum is similar to that of Type IIB superstring theory. There is one notable difference: the fermions are non-chiral. We further consider 'noncritical' generalizations of the supersymmetric theory using the superspace formulation. There is an infinite range of possible string theories similar to the supercritical string theories. We comment on the connection between the critical non-relativistic string theory and the lightlike Linear Dilaton theory.
Fleeson, William; Jayawickreme, Eranda
2014-01-01
Personality researchers should modify models of traits to include mechanisms of differential reaction to situations. Whole Trait Theory does so via five main points. First, the descriptive side of traits should be conceptualized as density distributions of states. Second, it is important to provide an explanatory account of the Big 5 traits. Third, adding an explanatory account to the Big 5 creates two parts to traits, an explanatory part and a descriptive part, and these two parts should be recognized as separate entities that are joined into whole traits. Fourth, Whole Trait Theory proposes that the explanatory side of traits consists of social-cognitive mechanisms. Fifth, social-cognitive mechanisms that produce Big-5 states should be identified. PMID:26097268
Jones, Dean P.
2015-01-01
Metazoan genomes encode exposure memory systems to enhance survival and reproductive potential by providing mechanisms for an individual to adjust during lifespan to environmental resources and challenges. These systems are inherently redox networks, arising during evolution of complex systems with O2 as a major determinant of bioenergetics, metabolic and structural organization, defense, and reproduction. The network structure decreases flexibility from conception onward due to differentiation and cumulative responses to environment (exposome). The redox theory of aging is that aging is a decline in plasticity of genome–exposome interaction that occurs as a consequence of execution of differentiation and exposure memory systems. This includes compromised mitochondrial and bioenergetic flexibility, impaired food utilization and metabolic homeostasis, decreased barrier and defense capabilities and loss of reproductive fidelity and fecundity. This theory accounts for hallmarks of aging, including failure to maintain oxidative or xenobiotic defenses, mitochondrial integrity, proteostasis, barrier structures, DNA repair, telomeres, immune function, metabolic regulation and regenerative capacity. PMID:25863726
Esposito-Farese, Gilles; Pitrou, Cyril; Uzan, Jean-Philippe
2010-03-15
This article provides a general study of the Hamiltonian stability and the hyperbolicity of vector field models involving both a general function of the Faraday tensor and its dual, f(F{sup 2},FF-tilde), as well as a Proca potential for the vector field, V(A{sup 2}). In particular it is demonstrated that theories involving only f(F{sup 2}) do not satisfy the hyperbolicity conditions. It is then shown that in this class of models, the cosmological dynamics always dilutes the vector field. In the case of a nonminimal coupling to gravity, it is established that theories involving Rf(A{sup 2}) or Rf(F{sup 2}) are generically pathologic. To finish, we exhibit a model where the vector field is not diluted during the cosmological evolution, because of a nonminimal vector field-curvature coupling which maintains second-order field equations. The relevance of such models for cosmology is discussed.
Topology and perturbation theory
NASA Astrophysics Data System (ADS)
Manjavidze, J.
2000-08-01
This paper contains description of the fields nonlinear modes successive quantization scheme. It is shown that the path integrals for absorption part of amplitudes are defined on the Dirac (δ-like) functional measure. This permits arbitrary transformation of the functional integral variables. New form of the perturbation theory achieved by mapping the quantum dynamics in the space WG of the (action, angle)-type collective variables. It is shown that the transformed perturbation theory contributions are accumulated exactly on the boundary ∂WG. Abilities of the developed formalism are illustrated by the Coulomb problem. This model is solved in the WC=(angle, angular momentum, Runge-Lentz vector) space and the reason of its exact integrability is emptiness of ∂WC.
NASA Astrophysics Data System (ADS)
Correa, Diego H.; Silva, Guillermo A.
2008-07-01
We discuss how geometrical and topological aspects of certain 1/2-BPS type IIB geometries are captured by their dual operators in N = 4 Super Yang-Mills theory. The type IIB solutions are characterized by arbitrary droplet pictures in a plane and we consider, in particular, axially symmetric droplets. The 1-loop anomalous dimension of the dual gauge theory operators probed with single traces is described by some bosonic lattice Hamiltonians. These Hamiltonians are shown to encode the topology of the droplets. In appropriate BMN limits, the Hamiltonians spectrum reproduces the spectrum of near-BPS string excitations propagating along each of the individual edges of the droplet. We also study semiclassical regimes for the Hamiltonians. For droplets having disconnected constituents, the Hamiltonian admits different complimentary semiclassical descriptions, each one replicating the semiclassical description for closed strings extending in each of the constituents.
Correa, Diego H.; Silva, Guillermo A.
2008-07-28
We discuss how geometrical and topological aspects of certain (1/2)-BPS type IIB geometries are captured by their dual operators in N = 4 Super Yang-Mills theory. The type IIB solutions are characterized by arbitrary droplet pictures in a plane and we consider, in particular, axially symmetric droplets. The 1-loop anomalous dimension of the dual gauge theory operators probed with single traces is described by some bosonic lattice Hamiltonians. These Hamiltonians are shown to encode the topology of the droplets. In appropriate BMN limits, the Hamiltonians spectrum reproduces the spectrum of near-BPS string excitations propagating along each of the individual edges of the droplet. We also study semiclassical regimes for the Hamiltonians. For droplets having disconnected constituents, the Hamiltonian admits different complimentary semiclassical descriptions, each one replicating the semiclassical description for closed strings extending in each of the constituents.
Panarchy: theory and application
Allen, Craig R.; Angeler, David G.; Garmestani, Ahjond S.; Gunderson, Lance H.; Holling, Crawford S.
2014-01-01
The concept of panarchy provides a framework that characterizes complex systems of people and nature as dynamically organized and structured within and across scales of space and time. It has been more than a decade since the introduction of panarchy. Over this period, its invocation in peer-reviewed literature has been steadily increasing, but its use remains primarily descriptive and abstract. Here, we discuss the use of the concept in the literature to date, highlight where the concept may be useful, and discuss limitations to the broader applicability of panarchy theory for research in the ecological and social sciences. Finally, we forward a set of testable hypotheses to evaluate key propositions that follow from panarchy theory.
Walsh, Timothy Francis; Reese, Garth M.; Bhardwaj, Manoj Kumar
2011-11-01
Salinas provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Salinas. For a more detailed description of how to use Salinas, we refer the reader to Salinas, User's Notes. Many of the constructs in Salinas are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Salinas are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature.
Gelman, Susan A.; Legare, Cristine H.
2013-01-01
Human cognition is characterized by enormous variability and structured by universal psychological constraints. The focus of this chapter is on the development of knowledge acquisition because it provides important insight into how the mind interprets new information and constructs new ways of understanding. We propose that mental content can be productively approached by examining the intuitive causal explanatory “theories” that people construct to explain, interpret, and intervene on the world around them, including theories of mind, of biology, or of physics. A substantial amount of research in cognitive developmental psychology supports the integral role of intuitive theories in human learning and provides evidence that they structure, constrain, and guide the development of human cognition. PMID:23436950
NASA Technical Reports Server (NTRS)
Wright, S. E.
1978-01-01
A theory is described for the radiation emission emission from acoustic multipole sources. The sources can be stationary or moving at speeds including supersonic and experience stationary or moving disturbances. The effect of finite source distributions and disturbances is investigated as well as the manner in which they interact. Distinction is made between source distributions that responsed as a function of time and those that respond as a function of space.
NASA Technical Reports Server (NTRS)
Callier, Frank M.; Desoer, Charles A.
1991-01-01
The aim of this book is to provide a systematic and rigorous access to the main topics of linear state-space system theory in both the continuous-time case and the discrete-time case; and the I/O description of linear systems. The main thrusts of the work are the analysis of system descriptions and derivations of their properties, LQ-optimal control, state feedback and state estimation, and MIMO unity-feedback systems.
Astrophysical materials science: Theory
NASA Technical Reports Server (NTRS)
Ashcroft, N. W.
1984-01-01
A method of structural expansions for use in determining the equation of state of metallic hydrogen (and indeed other metals) up to the 4th order in the perturbation theory was developed. The electrical and thermal transport properties of the planetary interior of Jupiter were calculated. The nature of the interaction between molecules at short range and the importance of multicenter terms in arriving at an adequate description of the thermodynamic functions of condensed molecular hydrogen were also investigated.
Paleo, Bruno Woltzenlogel
2012-01-01
Axiomatization of Physics (and science in general) has many drawbacks that are correctly criticized by opposing philosophical views of science. This paper shows that, by giving formal proofs a more prominent role in the formalization, many of the drawbacks can be solved and many of the opposing views are naturally conciliated. Moreover, this approach allows, by means of proof theory, to open new conceptual bridges between the disciplines of Physics and Computer Science. PMID:24976655
Dielectronic recombination theory
LaGattuta, K.J.
1991-12-31
A theory now in wide use for the calculation of dielectronic recombination cross sections ({sigma}{sup DR}) and rate coefficients ({alpha}{sup DR}) was one introduced originally by Feshbach for nuclear physics applications, and then later adapted for atomic scattering problems by Hahn. In the following, we briefly review this theory in a very general form, which allows one to account for the effects of overlapping and interacting resonances, as well as continuum-continuum coupling. An extension of our notation will then also allow for the inclusion of the effects of direct radiative recombination, along with a treatment of the interference between radiative and dielectronic recombination. Other approaches to the calculation of {sigma}{sup DR} have been described by Fano and by Seaton. We will not consider those theories here. Calculations of {alpha}{sup DR} have progressed considerably over the last 25 years, since the early work of Burgess. Advances in the reliability of theoretical predictions have also been promoted recently b a variety of direct laboratory measurements of {sigma}{sup DR}. While the measurements of {sigma}{sup DR} for {delta}n {ne} 0 excitations have tended to agree very well with calculations, the case of {delta}n = 0 has been much problematic. However, by invoking a mechanism originally proposed by Jacobs, which takes into account the effect of stray electric fields on high Rydberg states (HRS) participating in the DR process, new calculations have improved the agreement between theory and experiment for these cases. Nevertheless, certain discrepancies still remain.
Situational theory of leadership.
Waller, D J; Smith, S R; Warnock, J T
1989-11-01
The situational theory of leadership and the LEAD instruments for determining leadership style are explained, and the application of the situational leadership theory to the process of planning for and implementing organizational change is described. Early studies of leadership style identified two basic leadership styles: the task-oriented autocratic style and the relationship-oriented democratic style. Subsequent research found that most leaders exhibited one of four combinations of task and relationship behaviors. The situational leadership theory holds that the difference between the effectiveness and ineffectiveness of the four leadership styles is the appropriateness of the leader's behavior to the particular situation in which it is used. The task maturity of the individual or group being led must also be accounted for; follower readiness is defined in terms of the capacity to set high but attainable goals, willingness or ability to accept responsibility, and possession of the necessary education or experience for a specific task. A person's leadership style, range, and adaptability can be determined from the LEADSelf and LEADOther questionnaires. By applying the principles of the situational leadership theory and adapting their managerial styles to specific tasks and levels of follower maturity, the authors were successful in implementing 24-hour pharmacokinetic dosing services provided by staff pharmacists with little previous experience in clinical services. The situational leadership model enables a leader to identify a task, set goals, determine the task maturity of the individual or group, select an appropriate leadership style, and modify the style as change occurs. Pharmacy managers can use this model when implementing clinical pharmacy services. PMID:2589352
NASA Technical Reports Server (NTRS)
Wolpert, David H.
2005-01-01
Probability theory governs the outcome of a game; there is a distribution over mixed strat.'s, not a single "equilibrium". To predict a single mixed strategy must use our loss function (external to the game's players. Provides a quantification of any strategy's rationality. Prove rationality falls as cost of computation rises (for players who have not previously interacted). All extends to games with varying numbers of players.
NASA Astrophysics Data System (ADS)
Hartsock, Robert
2011-10-01
The Least Particle Theory states that the universe was cast as a great sea of energy. MaX Planck declared a quantum of energy to be the least value in the universe. We declare the quantum of energy to be the least particle in the universe. Stephen Hawking declared quantum mechanics to be of no value in todays gross mechanics. That's like saying the number 1 has no place in mathematics.
Chowdhry, M
2000-01-01
SUMMARY This paper discusses the role of the personal experience in the writing process. Using a personal/journal writing style the author charts the journey of a recent play Skin into Rainbows from first draft to production. The author plays with the constructs of writing and juxtapositions these against a form of Knot Theory to measure their value, playing with math and language techniques in a search for truth. PMID:24802683
Relativistic theory of gravitation
Logunov, A.A.; Mestvirishvili, M.A.
1986-01-01
In the present paper a relativistic theory of gravitation (RTG) is unambiguously constructed on the basis of the special relativity and geometrization principle. In this a gravitational field is treated as the Faraday--Maxwell spin-2 and spin-0 physical field possessing energy and momentum. The source of a gravitational field is the total conserved energy-momentum tensor of matter and of a gravitational field in Minkowski space. In the RTG the conservation laws are strictly fulfilled for the energy-moment and for the angular momentum of matter and a gravitational field. The theory explains the whole available set of experiments on gravity. By virtue of the geometrization principle, the Riemannian space in our theory is of field origin, since it appears as an effective force space due to the action of a gravitational field on matter. The RTG leads to an exceptionally strong prediction: The universe is not closed but just ''flat.'' This suggests that in the universe a ''missing mass'' should exist in a form of matter.
Probabilistic theories with purification
Chiribella, Giulio; D'Ariano, Giacomo Mauro; Perinotti, Paolo
2010-06-15
We investigate general probabilistic theories in which every mixed state has a purification, unique up to reversible channels on the purifying system. We show that the purification principle is equivalent to the existence of a reversible realization of every physical process, that is, to the fact that every physical process can be regarded as arising from a reversible interaction of the system with an environment, which is eventually discarded. From the purification principle we also construct an isomorphism between transformations and bipartite states that possesses all structural properties of the Choi-Jamiolkowski isomorphism in quantum theory. Such an isomorphism allows one to prove most of the basic features of quantum theory, like, e.g., existence of pure bipartite states giving perfect correlations in independent experiments, no information without disturbance, no joint discrimination of all pure states, no cloning, teleportation, no programming, no bit commitment, complementarity between correctable channels and deletion channels, characterization of entanglement-breaking channels as measure-and-prepare channels, and others, without resorting to the mathematical framework of Hilbert spaces.
NASA Technical Reports Server (NTRS)
Bass, J; Agostini, L
1955-01-01
The theory of turbulence reached its full growth at the end of the 19th century as a result of the work by Boussinesq and Reynolds. It then underwent a long period of stagnation which ended under the impulse given to it by the development of wind tunnels caused by the needs of aviation. Numerous researchers, attempted to put Reynolds' elementary statistical theory into a more precise form. During the war, some isolated scientists - von Weizsacker and Heisenberg in Germany, Kolmogoroff in Russia, Onsager in the U.S.A. - started a program of research. By a system of assumptions which make it possible to approach the structure of turbulence in well-defined limiting conditions quantitatively, they obtained a certain number of laws on the correlations and the spectrum. Since the late reports have improved the mathematical language of turbulence, it was deemed advisable to start with a detailed account of the mathematical methods applicable to turbulence, inspired at first by the work of the French school, above all for the basic principles, then the work of the foreigners, above all for the theory of the spectrum.
Celani, David P
2016-06-01
Fairbairn's unique structural theory with its three pairs of selves and objects has proven to be a highly usable and practical model of the human psyche, yet it has remained a minor player in the world of psychoanalysis. There are a number of factors that account for its lack of popularity, foremost among them the timing of the model's introduction to the analytic community. Fairbairn's four successive papers that described his metapsychology (1940, 1941, 1943, and 1944) were published just after Freud's death, when his theory was the dominant model of psychoanalysis. Additionally, Fairbairn's model was incomplete, used unfamiliar terminology, and, in its singularity, forced the analyst to abandon drive theory, the heart of Freud's metapsychology. This paper will examine and update Fairbairn's unique model of change-from the outset of pathology that begins with attachment to bad objects, to their metamorphosis into internal structures and finally to techniques of treatment that reduce their influence on the patients' internal world. The treatment section carefully follows Fairbairn's metapsychology, and focuses first on the analyst becoming a good object in the eyes of the patient, then unearthing bad object memories in a safe and compassionate interpersonal environment, engaging the patient's substructures in a manner that does not intensify preexisting internal templates, and finally aiding the patient in resuming his or her stalled emotional development. This exegesis of Fairbairn original model, along with recent modifications that have been made to it, demonstrates the consistency, clear focus, and utility of this little-known metapsychology. PMID:27248039
Constructor theory of information
Deutsch, David; Marletto, Chiara
2015-01-01
We propose a theory of information expressed solely in terms of which transformations of physical systems are possible and which are impossible—i.e. in constructor-theoretic terms. It includes conjectured, exact laws of physics expressing the regularities that allow information to be physically instantiated. Although these laws are directly about information, independently of the details of particular physical instantiations, information is not regarded as an a priori mathematical or logical concept, but as something whose nature and properties are determined by the laws of physics alone. This theory solves a problem at the foundations of existing information theory, namely that information and distinguishability are each defined in terms of the other. It also explains the relationship between classical and quantum information, and reveals the single, constructor-theoretic property underlying the most distinctive phenomena associated with the latter, including the lack of in-principle distinguishability of some states, the impossibility of cloning, the existence of pairs of variables that cannot simultaneously have sharp values, the fact that measurement processes can be both deterministic and unpredictable, the irreducible perturbation caused by measurement, and locally inaccessible information (as in entangled systems). PMID:25663803
NASA Astrophysics Data System (ADS)
Mojaza, Matin; Pica, Claudio; Sannino, Francesco
2010-12-01
We compute the nonzero temperature free energy up to the order g6ln(1/g) in the coupling constant for vectorlike SU(N) gauge theories featuring matter transforming according to different representations of the underlying gauge group. The number of matter fields, i.e. flavors, is arranged in such a way that the theory develops a perturbative stable infrared fixed point at zero temperature. Because of large distance conformality we trade the coupling constant with its fixed point value and define a reduced free energy which depends only on the number of flavors, colors, and matter representation. We show that the reduced free energy changes sign, at the second, fifth, and sixth order in the coupling, when decreasing the number of flavors from the upper end of the conformal window. If the change in sign is interpreted as a signal of an instability of the system then we infer a critical number of flavors. Surprisingly this number, if computed to the order g2, agrees with previous predictions for the lower boundary of the conformal window for nonsupersymmetric gauge theories. The higher order results tend to predict a higher number of critical flavors. These are universal properties, i.e. they are independent of the specific matter representation.
Beyond mean field theory: statistical field theory for neural networks
Buice, Michael A; Chow, Carson C
2014-01-01
Mean field theories have been a stalwart for studying the dynamics of networks of coupled neurons. They are convenient because they are relatively simple and possible to analyze. However, classical mean field theory neglects the effects of fluctuations and correlations due to single neuron effects. Here, we consider various possible approaches for going beyond mean field theory and incorporating correlation effects. Statistical field theory methods, in particular the Doi–Peliti–Janssen formalism, are particularly useful in this regard. PMID:25243014
Singularity theory and N = 2 superconformal field theories
Warner, N.P.
1989-01-01
The N = 2 superconformal field theories that appear at the fixed points of the renormalization group flows of Landau-Ginsburg models are discussed. Some of the techniques of singularity theory are employed to deduce properties of these superconformal theories. These ideas are then used to deduce the relationship between Calabi-Yau compactifications and tensored discrete series models. The chiral rings of general N = 2 superconformal theories are also described. 14 refs.
Critical Theory: Implications for School Leadership Theory and Practice.
ERIC Educational Resources Information Center
Peca, Kathy
The school leader's behaviors are inspired by theories, and theories are intrinsic to practice. This paper provides an overview of an emerging perspective in educational administration, critical theory. The paper first highlights the philosophies of Immanuel Kant, Fichte, Hegel, Marx, and the Frankfurt School. It then discusses critical theory…
Informal Theory: The Ignored Link in Theory-to-Practice
ERIC Educational Resources Information Center
Love, Patrick
2012-01-01
Applying theory to practice in student affairs is dominated by the assumption that formal theory is directly applied to practice. Among the problems with this assumption is that many practitioners believe they must choose between their lived experiences and formal theory, and that graduate students are taught that their experience "does not…
Contrasting Ohlsson's Resubsumption Theory with Chi's Categorical Shift Theory
ERIC Educational Resources Information Center
Chi, Michelene T. H.; Brem, Sarah K.
2009-01-01
Ohlsson's proposal of resubsumption as the dominant process in conceptual, or nonmonotonic, change presents a worthy challenge to more established theories, such as Chi's theory of ontological shift. The two approaches differ primarily in that Ohlsson's theory emphasizes a process of learning in which narrower, more specific concepts are subsumed…
Targeting the Teaching of Theory.
ERIC Educational Resources Information Center
Walton, Charles W.
1981-01-01
Suggests that six target areas in the teaching of theory and musicianship need more attention and emphasis: listening, analysis, music reading, creativity, music writing, and keyboard harmony. Discusses content and sequence in music theory and presents two sample applications. (SJL)
Theories Supporting Transfer of Training.
ERIC Educational Resources Information Center
Yamnill, Siriporn; McLean, Gary N.
2001-01-01
Reviews theories about factors affecting the transfer of training, including theories on motivation (expectancy, equity, goal setting), training transfer design (identical elements, principle, near and far), and transfer climate (organizational). (Contains 36 references.) (SK)
Schwarz, John H.
1999-07-15
In this talk I will survey some of the basic facts about superstring theories in 10 dimensions and the dualities that relate them to M theory in 11 dimensions. Then I will mention some important unresolved issues.
NASA Technical Reports Server (NTRS)
Ni, W.-T.
1973-01-01
A new relativistic theory of gravity is presented. This theory agrees with all experiments to date. It is a metric theory; it is Lagrangian-based; and it possesses a preferred frame with conformally flat space slices. With an appropriate choice of certain adjustable functions and parameters and of the cosmological model, this theory possesses precisely the same post-Newtonian limit as general relativity.
Inquiry Calculus and Information Theory
NASA Astrophysics Data System (ADS)
Center, Julian L.
2009-12-01
We consider the relationship between information theory and a calculus of inquiries. We show how an inquiry calculus can be constructed using lattice theory, and how the inquiry calculus relates to information theory. The key idea is to identify both inquiries and variables with partitions of the state space. We also show an approach to extending information theory that deals with the problem of negative entropies on questions that do not correspond to partitions.
Modern Biological Theories of Aging
Jin, Kunlin
2010-01-01
Despite recent advances in molecular biology and genetics, the mysteries that control human lifespan are yet to be unraveled. Many theories, which fall into two main categories: programmed and error theories, have been proposed to explain the process of aging, but neither of them appears to be fully satisfactory. These theories may interact with each other in a complex way. By understanding and testing the existing and new aging theories, it may be possible to promote successful aging. PMID:21132086
Logarithmic conformal field theory
NASA Astrophysics Data System (ADS)
Gainutdinov, Azat; Ridout, David; Runkel, Ingo
2013-12-01
Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more
Chaos Theory and Post Modernism
ERIC Educational Resources Information Center
Snell, Joel
2009-01-01
Chaos theory is often associated with post modernism. However, one may make the point that both terms are misunderstood. The point of this article is to define both terms and indicate their relationship. Description: Chaos theory is associated with a definition of a theory dealing with variables (butterflies) that are not directly related to a…
Theories of the Alcoholic Personality.
ERIC Educational Resources Information Center
Cox, W. Miles
Several theories of the alcoholic personality have been devised to determine the relationship between the clusters of personality characteristics of alcoholics and their abuse of alcohol. The oldest and probably best known theory is the dependency theory, formulated in the tradition of classical psychoanalysis, which associates the alcoholic's…
Play Theories: A Contemporary Review.
ERIC Educational Resources Information Center
Mellou, Eleni
1994-01-01
Reviews two sets of play theories, classical and modern, noting that the reason and purpose for play are explained by classical theories; the role of play in child development, determined by modern theories. States that process of play has dual functions of personal expression and social adaptation. Examines the relationship between play and…
Informational derivation of quantum theory
NASA Astrophysics Data System (ADS)
Chiribella, Giulio; D'Ariano, Giacomo Mauro; Perinotti, Paolo
2011-07-01
We derive quantum theory from purely informational principles. Five elementary axioms—causality, perfect distinguishability, ideal compression, local distinguishability, and pure conditioning—define a broad class of theories of information processing that can be regarded as standard. One postulate—purification—singles out quantum theory within this class.
Knot Theory with Young Children
ERIC Educational Resources Information Center
Handa, Yuichi; Mattman, Thomas
2008-01-01
There are many interesting explorations that can be done in knot theory, the study of mathematical knots. This article offers some knot theory activities that are appropriate for elementary grade children. These activities teach some basic concepts from knot theory as a natural extension of commonly-taught geometric ideas. (Contains 10 figures.)
Networking Theories by Iterative Unpacking
ERIC Educational Resources Information Center
Koichu, Boris
2014-01-01
An iterative unpacking strategy consists of sequencing empirically-based theoretical developments so that at each step of theorizing one theory serves as an overarching conceptual framework, in which another theory, either existing or emerging, is embedded in order to elaborate on the chosen element(s) of the overarching theory. The strategy is…
Coding Issues in Grounded Theory
ERIC Educational Resources Information Center
Moghaddam, Alireza
2006-01-01
This paper discusses grounded theory as one of the qualitative research designs. It describes how grounded theory generates from data. Three phases of grounded theory--open coding, axial coding, and selective coding--are discussed, along with some of the issues which are the source of debate among grounded theorists, especially between its…
Program Theory Evaluation: Logic Analysis
ERIC Educational Resources Information Center
Brousselle, Astrid; Champagne, Francois
2011-01-01
Program theory evaluation, which has grown in use over the past 10 years, assesses whether a program is designed in such a way that it can achieve its intended outcomes. This article describes a particular type of program theory evaluation--logic analysis--that allows us to test the plausibility of a program's theory using scientific knowledge.…
ERIC Educational Resources Information Center
Pryor, Robert G. L.; Bright, Jim
2003-01-01
Four theoretical streams--contexualism/ecology, systems theory, realism/constructivism, and chaos theory--contributed to a theory of individuals as complex, unique, nonlinear, adaptive chaotic and open systems. Individuals use purposive action to construct careers but can make maladaptive and inappropriate choices. (Contains 42 references.) (SK)
NASA Astrophysics Data System (ADS)
Choy, Ting-Pong
One of the leading problems in condensed matter physics is what state of matter obtain when there is a strong Coulomb repulsion between the electrons. One of the exotic examples is the high temperature superconductivity which was discovered in copper-oxide ceramics (cuprates) over twenty years ago. Thus far, a satisfactory theory is absent. In particular, the nature of the electron state outside the superconducting phase remains controversial. In analogy with the BCS theory of a conventional superconductor, in which the metal is well known to be a Fermi liquid, a complete understanding of the normal state of cuprate is necessary prior to the study of the superconducting mechanism in the high temperature superconductors. In this thesis, we will provide a theory for these exotic normal state properties by studying the minimal microscopic model which captures the physics of strong electron correlation. Even in such a simple microscopic model, striking properties including charge localization and presence of a Luttinger surface resemble the normal state properties of cuprate. An exact low energy theory of a doped Mott insulator will be constructed by explicitly integrating (rather than projecting) out the degrees of freedom far away from the chemical potential. The exact low energy theory contains degrees of freedom that cannot be obtained from projective schemes. In particular, a charge 2e bosonic field which is not made out of elemental excitations emerges at low energies. Such a field accounts for dynamical spectral weight transfer across the Mott gap. At half-filling, we show that two such excitations emerge which play a crucial role in preserving the Luttinger surface along which the single-particle Green function vanishes. We also apply this method to the Anderson-U impurity and show that in addition to the Kondo interaction, bosonic degrees of freedom appear as well. We show that many of the normal state properties of the cuprates can result from this new charge
NASA Astrophysics Data System (ADS)
German, Randall M.
1996-01-01
Although sintering is an essential process in the manufacture of ceramics and certain metals, as well as several other industrial operations, until now, no single book has treated both the background theory and the practical application of this complex and often delicate procedure. In Sintering Theory and Practice, leading researcher and materials engineer Randall M. German presents a comprehensive treatment of this subject that will be of great use to manufacturers and scientists alike. This practical guide to sintering considers the fact that while the bonding process improves strength and other engineering properties of the compacted material, inappropriate methods of control may lead to cracking, distortion, and other defects. It provides a working knowledge of sintering, and shows how to avoid problems while accounting for variables such as particle size, maximum temperature, time at that temperature, and other problems that may cause changes in processing. The book describes the fundamental atomic events that govern the transformation from particles to solid, covers all forms of the sintering process, and provides a summary of many actual production cycles. Building from the ground up, it begins with definitions and progresses to measurement techniques, easing the transition, especially for students, into advanced topics such as single-phase solid-state sintering, microstructure changes, the complications of mixed particles, and pressure-assisted sintering. German draws on some six thousand references to provide a coherent and lucid treatment of the subject, making scientific principles and practical applications accessible to both students and professionals. In the process, he also points out and avoids the pitfalls found in various competing theories, concepts, and mathematical disputes within the field. A unique opportunity to discover what sintering is all about--both in theory and in practice What is sintering? We see the end product of this thermal
Logarithmic conformal field theory
NASA Astrophysics Data System (ADS)
Gainutdinov, Azat; Ridout, David; Runkel, Ingo
2013-12-01
Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more
NASA Astrophysics Data System (ADS)
Stanton, John F.
2015-05-01
The interaction between quantum-mechanical theory and spectroscopy is one of the most fertile interfaces in all of science, and has a richly storied history. Of course it was spectroscopy that provided essentially all of the evidence that not all was well (or, perhaps more correctly put, complete) with the world of 19th century classical physics. From the discoveries of the dark lines in the solar spectrum by Fraunhöfer in 1814 to the curiously simple geometric formula discovered seventy years later that described the hydrogen atom spectrum, spectroscopy and spectroscopists have consistently identified the areas of atomic and molecular science that are most in need of hard thinking by theoreticians. The rest of the story, of course, is well-known: spectroscopic results were used to understand and motivate the theory of radioactivity and ultimately the quantum theory, first in its immature form that was roughly contemporaneous with the first World War, and then the Heisenberg-Schrödinger-Dirac version that has withstood the test of time. Since the basic principles of quantum mechanics ware first understood, the subject has been successfully used to understand the patterns found in spectra, and how these relate to molecular structure, symmetry, energy levels, and dynamics. But further understanding required to attain these intellectual achievements has often come only as a result of vital and productive interactions between theoreticians and spectroscopists (of course, many people have strengths in both areas). And indeed, a field that might be termed "theoretical spectroscopy" was cultivated and is now an important part of modern molecular science.
Erickson, S.A. Jr.
1991-03-20
The purpose of this monograph is to start a theory of deterrence which has the capability of quantitatively answering the question of what is required to deter a nation or alliance from certain acts. Despite the existence of voluminous writing on deterrence, from the beginning of the nuclear age and even before, none of it attempts a theoretical discussion of how to calculate what it takes to deter a country from committing some acts which are objectionable to another country. Many theories of deterrence have already been created. They have exclusively been of two separate forms -- those of the social scientists, which deal with political questions, and how the concept of mass destruction psychological deters the initiation of war; and those of the mathematicians, who model the quantities of one country`s arsenal of strategic systems needed to destroy a certain portion of another country`s. Only the latter is quantitative, but they lack an essential element added to answer the question ``How much is enough?`` In order to use the techniques of operations research on the questions of what type and amount of weapons are adequate for deterrence, the definitions of quantities occurring in the calculations need to be made in quantifiable way. Numbers of weapons have been the only quantified parameter in previous deterrence calculations. Yet weapons alone do not deter. The threat of destruction and damage does. How is that threatenable damage to be measured, and as through defensive system construction, counterforce capability improvement, arms control, or other means, it becomes less when is the threshold for deterrence met and crossed? The calculation of this damage, and the implication of that damage to decision-makers capable of making a war initiation decision, is a complicated process, and it is what constitutes a theory of deterrence. 36 refs.
A 3+1 formalism for quantum electrodynamical corrections to Maxwell equations in general relativity
NASA Astrophysics Data System (ADS)
Pétri, J.
2015-08-01
Magnetized neutron stars constitute a special class of compact objects harbouring gravitational fields that deviate strongly from the Newtonian weak field limit. Moreover, strong electromagnetic fields anchored into the star give rise to non-linear corrections to Maxwell equations described by quantum electrodynamics (QED). Electromagnetic fields close to or above the critical value of BQ = 4.4 × 109 T are probably present in some pulsars and for most of the magnetars. To account properly for emission emanating from the neutron star surface like for instance thermal radiation and its polarization properties, it is important to include general relativistic (GR) effects simultaneously with non-linear electrodynamics. This can be achieved through a 3+1 formalism known in general relativity and that incorporates QED perturbations to Maxwell equations. Starting from the lowest order corrections to the Lagrangian for the electromagnetic field, as given for instance by Born-Infeld or Euler-Heisenberg theory, we derive the non-linear Maxwell equations in general relativity including quantum vacuum effects. We also derive a prescription for the force-free limit and show that these equations can be solved with classical finite volume methods for hyperbolic conservation laws. It is therefore straightforward to include general relativity and QED in the description of neutron star magnetospheres by using standard classical numerical techniques borrowed from Maxwell and Newton theory. As an application, we show that spin-down luminosity corrections associated with QED effects are negligible with respect to GR corrections.
Nonlinear perturbations of cosmological scalar fields with non-standard kinetic terms
NASA Astrophysics Data System (ADS)
Renaux-Petel, Sébastien; Tasinato, Gianmassimo
2009-01-01
We adopt a covariant formalism to derive exact evolution equations for nonlinear perturbations, in a universe dominated by two scalar fields. These scalar fields are characterized by non-canonical kinetic terms and an arbitrary field space metric, a situation typically encountered in inflationary models inspired by string theory. We decompose the nonlinear scalar perturbations into adiabatic and entropy modes, generalizing the definition adopted in the linear theory, and we derive the corresponding exact evolution equations. We also obtain a nonlinear generalization of the curvature perturbation on uniform density hypersurfaces, showing that on large scales it is sourced only by the nonlinear version of the entropy perturbation. We then expand these equations to second order in the perturbations, using a coordinate based formalism. Our results are relatively compact and elegant and enable one to identify the new effects coming from the non-canonical structure of the scalar fields Lagrangian. We also explain how to analyze, in our formalism, the interesting scenario of multi-field Dirac-Born-Infeld inflation.
Open/closed string duality and relativistic fluids
NASA Astrophysics Data System (ADS)
Niarchos, Vasilis
2016-07-01
We propose an open/closed string duality in general backgrounds extending previous ideas about open string completeness by Ashoke Sen. Our proposal sets up a general version of holography that works in gravity as a tomographic principle. We argue, in particular, that previous expectations of a supergravity/Dirac-Born-Infeld (DBI) correspondence are naturally embedded in this conjecture and can be tested in a well-defined manner. As an example, we consider the correspondence between open string field theories on extremal D-brane setups in flat space in the large-N , large 't Hooft limit, and asymptotically flat solutions in ten-dimensional type II supergravity. We focus on a convenient long-wavelength regime, where specific effects of higher-spin open string modes can be traced explicitly in the dual supergravity computation. For instance, in this regime we show how the full Abelian DBI action arises from supergravity as a straightforward reformulation of relativistic hydrodynamics. In the example of a (2 +1 )-dimensional open string theory this reformulation involves an Abelian Hodge duality. We also point out how different deformations of the DBI action, related to higher-derivative corrections and non-Abelian effects, can arise in this context as deformations in corresponding relativistic hydrodynamics.
Crystal clear lessons on the microstructure of spacetime and modified gravity
NASA Astrophysics Data System (ADS)
Lobo, Francisco S. N.; Olmo, Gonzalo J.; Rubiera-Garcia, D.
2015-06-01
We argue that a microscopic structure for spacetime such as that expected in a quantum foam scenario, in which microscopic wormholes and other topological structures should play a relevant role, might lead to an effective metric-affine geometry at larger scales. This idea is supported by the role that microscopic defects play in crystalline structures. With an explicit model, we show that wormhole formation is possible in a metric-affine scenario, where the wormhole and the matter fields play a role analogous to that of defects in crystals. Such wormholes also arise in Born-Infeld gravity, which is favored by an analogy with the estimated mass of a point defect in condensed matter systems. We also point out that in metric-affine geometries, Einstein's equations with an effective cosmological constant appear as an attractor in the vacuum limit for a vast family of theories of gravity. This illustrates how lessons from solid state physics can be useful in unveiling the properties of the microcosmos and defining new avenues for modified theories of gravity.
Three dimensional nonlinear magnetic AdS solutions through topological defects
NASA Astrophysics Data System (ADS)
Hendi, S. H.; Panah, B. Eslam; Momennia, M.; Panahiyan, S.
2015-09-01
Inspired by large applications of topological defects in describing different phenomena in physics, and considering the importance of three dimensional solutions in AdS/CFT correspondence, in this paper we obtain magnetic anti-de Sitter solutions of nonlinear electromagnetic fields. We take into account three classes of nonlinear electrodynamic models; first two classes are the well-known Born-Infeld like models including logarithmic and exponential forms and third class is known as the power Maxwell invariant nonlinear electrodynamics. We investigate the effects of these nonlinear sources on three dimensional magnetic solutions. We show that these asymptotical AdS solutions do not have any curvature singularity and horizon. We also generalize the static metric to the case of rotating solutions and find that the value of the electric charge depends on the rotation parameter. Finally, we consider the quadratic Maxwell invariant as a correction of Maxwell theory and we investigate the effects of nonlinearity as a correction. We study the behavior of the deficit angle in presence of these theories of nonlinearity and compare them with each other. We also show that some cases with negative deficit angle exists which are representing objects with different geometrical structure. We also show that in case of the static only magnetic field exists whereas by boosting the metric to rotating one, electric field appears too.
NASA Astrophysics Data System (ADS)
Milgrom, Mordehai
2002-02-01
I investigate the properties of forces on bodies in theories governed by the generalized Poisson equation μ(|ϕ| /a0)ϕ] ∝ Gρ, for the potential ϕ produced by a distribution of sources ρ. This equation describes, inter alia, media with a response coefficient, μ, that depends on the field strength, such as in nonlinear, dielectric or diamagnetic, media; nonlinear transport problems with field-strength-dependent conductivity or diffusion coefficient; nonlinear electrostatics, as in the Born-Infeld theory; certain stationary potential flows in compressible fluids, in which case the forces act on sources or obstacles in the flow. The expressions for the force on a point charge are derived exactly for the limits of very low and very high charge. The force on an arbitrary body in an external field of asymptotically constant gradient, -g0, is shown to be F = Qg0, where Q is the total effective charge of the body. The corollary Q = 0 → F = 0 is a generalization of d'Alembert's paradox. I show that for G > 0 (as in Newtonian gravity) two point charges of the same (opposite) sign still attract (repel). The opposite is true for G < 0. I discuss its generalization to extended bodies and derive virial relations.
Homogeneous and isotropic cosmologies with nonlinear electromagnetic radiation
Vollick, Dan N.
2008-09-15
In this paper I examine cosmological models that contain a stochastic background of nonlinear electromagnetic radiation. I show that for Born-Infeld electrodynamics the equation of state parameter, w=P/{rho}, remains close to 1/3 throughout the evolution of the universe if E{sup 2}=B{sup 2} in the late universe to a high degree of accuracy. Theories with electromagnetic Lagrangians of the form L=-(1/4)F{sup 2}+{alpha}F{sup 4} have recently been studied in magnetic universes, where the electric field vanishes. It was shown that the F{sup 4} term can produce a bounce in the early universe, avoiding an initial singularity. Here I show that the inclusion of an electric field, with E{sup 2}{approx_equal}B{sup 2} in the late universe, eliminates the bounce and the universe begins with an initial singularity. I also examine theories with Lagrangians of the form L=-(1/4)F{sup 2}-{mu}{sup 8}/F{sup 2}, which have been shown to produce a period of late time accelerated expansion in magnetic universes. I show that, if an electric field is introduced, the accelerated phase will only occur if E{sup 2}<3B{sup 2}.
Koivisto, Tomi; Wills, Danielle; Zavala, Ivonne E-mail: d.e.wills@durham.ac.uk
2014-06-01
Disformally coupled cosmologies arise from Dirac-Born-Infeld actions in Type II string theories, when matter resides on a moving hidden sector D-brane. Since such matter interacts only very weakly with the standard model particles, this scenario can provide a natural origin for the dark sector of the universe with a clear geometrical interpretation: dark energy is identified with the scalar field associated to the D-brane's position as it moves in the internal space, acting as quintessence, while dark matter is identified with the matter living on the D-brane, which can be modelled by a perfect fluid. The coupling functions are determined by the (warped) extra-dimensional geometry, and are thus constrained by the theory. The resulting cosmologies are studied using both dynamical system analysis and numerics. From the dynamical system point of view, one free parameter controls the cosmological dynamics, given by the ratio of the warp factor and the potential energy scales. The disformal coupling allows for new scaling solutions that can describe accelerating cosmologies alleviating the coincidence problem of dark energy. In addition, this scenario may ameliorate the fine-tuning problem of dark energy, whose small value may be attained dynamically, without requiring the mass of the dark energy field to be unnaturally low.
The degeneracy problem in non-canonical inflation
Easson, Damien A.; Powell, Brian A. E-mail: brian.powell007@gmail.com
2013-03-01
While attempting to connect inflationary theories to observational physics, a potential difficulty is the degeneracy problem: a single set of observables maps to a range of different inflaton potentials. Two important classes of models affected by the degeneracy problem are canonical and non-canonical models, the latter marked by the presence of a non-standard kinetic term that generates observables beyond the scalar and tensor two-point functions on CMB scales. The degeneracy problem is manifest when these distinguishing observables go undetected. We quantify the size of the resulting degeneracy in this case by studying the most well-motivated non-canonical theory having Dirac-Born-Infeld Lagrangian. Beyond the scalar and tensor two-point functions on CMB scales, we then consider the possible detection of equilateral non-Gaussianity at Planck-precision and a measurement of primordial gravitational waves from prospective space-based laser interferometers. The former detection breaks the degeneracy with canonical inflation but results in poor reconstruction prospects, while the latter measurement enables a determination of n{sub T} which, while not breaking the degeneracy, can be shown to greatly improve the non-canonical reconstruction.
Cosmological constraints on general, single field inflation
NASA Astrophysics Data System (ADS)
Agarwal, Nishant; Bean, Rachel
2009-01-01
Inflation is now an accepted paradigm in standard cosmology, with its predictions consistent with observations of the cosmic microwave background. It lacks, however, a firm physical theory, with many possible theoretical origins beyond the simplest, canonical, slow-roll inflation, including Dirac-Born-Infeld inflation and k-inflation. We discuss how a hierarchy of Hubble flow parameters, extended to include the evolution of the inflationary sound speed, can be applied to compare a general, single field inflationary action with cosmological observational data. We show that it is important to calculate the precise scalar and tensor primordial power spectra by integrating the full flow and perturbation equations, since values of observables can deviate appreciably from those obtained using typical second-order Taylor expanded approximations in flow parameters. As part of this, we find that a commonly applied approximation for the tensor-to-scalar ratio, r≈16csγ, becomes poor (deviating by as much as 50%) as cs deviates from 1 and hence the Taylor expansion including next-to-leading order contribution terms involving cs is required. By integrating the full flow equations, we use a Monte-Carlo-Markov-Chain approach to impose constraints on the parameter space of general single field inflation, and reconstruct the properties of such an underlying theory in light of recent cosmic microwave background and large-scale structure observations.
NASA Astrophysics Data System (ADS)
Hehl, Friedrich W.; Obukhov, Yuri N.
The coupling of the electromagnetic field to gravity is an age-old problem. Presently, there is a resurgence of interest in it, mainly for two reasons: (i) Experimental investigations are under way with ever increasing precision, be it in the laboratory or by observing outer space. (ii) One desires to test out alternatives to Einstein’s gravitational theory, in particular those of a gauge-theoretical nature, like Einstein-Cartan theory or metric-afine gravity.— A clean discussion requires a reflection on the foundations of electrodynamics. If one bases electrodynamics on the conservation laws of electric charge and magnetic flux, one finds Maxwell’s equations expressed in terms of the excitation H = (D,H) and the field strength F = (E,B) without any intervention of the metric or the linear connection of spacetime. In other words, there is still no coupling to gravity. Only the constitutive law H = functional(F) mediates such a coupling. We discuss the different ways of how metric, nonmetricity, torsion, and curvature can come into play here. Along the way, we touch on non-local laws (Mashhoon), non-linear ones (Born-Infeld, Heisenberg-Euler, Plebaśki), linear ones, including the Abelian axion (Ni), and fid a method for deriving the metric from linear electrodynamics (Toupin, Schönberg). Finally, we discuss possible non-minimal coupling schemes.
NASA Technical Reports Server (NTRS)
Hsu, C. H.; Lan, C. E.
1984-01-01
A theory is developed for predicting wing rock characteristics. From available data, it can be concluded that wing rock is triggered by flow asymmetries, developed by negative or weakly positive roll damping, and sustained by nonlinear aerodynamic roll damping. A new nonlinear aerodynamic model that includes all essential aerodynamic nonlinearities is developed. The Beecham-Titchener method is applied to obtain approximate analytic solutions for the amplitude and frequency of the limit cycle based on the three degree-of-freedom equations of motion. An iterative scheme is developed to calculate the average aerodynamic derivatives and dynamic characteristics at limit cycle conditions. Good agreement between theoretical and experimental results is obtained.
London, R.A.
1983-09-30
The theory of optical flashes created by x- and ..gamma..-ray burst heating of stars in binaries is reviewed. Calculations of spectra due to steady-state x-ray reprocessing and estimates of the fundamental time scales for the non-steady case are discussed. The results are applied to the extant optical data from x-ray and ..gamma..-ray bursters. Finally, I review predictions of flashes from ..gamma..-ray bursters detectable by a state of the art all-sky optical monitor.
NASA Astrophysics Data System (ADS)
Hashimoto, Koji; Morita, Takeshi
2011-08-01
In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass-number (A) dependence r∝A1/3 for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multibaryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1)×A1/3[fm], which is consistent with experiments.
NASA Astrophysics Data System (ADS)
Holman, Gordon D.
The primary purpose of the Theory and Modeling Group meeting was to identify scientists engaged or interested in theoretical work pertinent to the Max '91 program, and to encourage theorists to pursue modeling which is directly relevant to data which can be expected to result from the program. A list of participants and their institutions is presented. Two solar flare paradigms were discussed during the meeting -- the importance of magnetic reconnection in flares and the applicability of numerical simulation results to solar flare studies.
Unifying Theories of Confidentiality
NASA Astrophysics Data System (ADS)
Banks, Michael J.; Jacob, Jeremy L.
This paper presents a framework for reasoning about the security of confidential data within software systems. A novelty is that we use Hoare and He's Unifying Theories of Programming (UTP) to do so and derive advantage from this choice. We identify how information flow between users can be modelled in the UTP and devise conditions for verifying that system designs may not leak secret information to untrusted users. We also investigate how these conditions can be combined with existing notions of refinement to produce refinement relations suitable for deriving secure implementations of systems.
NASA Technical Reports Server (NTRS)
Holman, Gordon D.
1989-01-01
The primary purpose of the Theory and Modeling Group meeting was to identify scientists engaged or interested in theoretical work pertinent to the Max '91 program, and to encourage theorists to pursue modeling which is directly relevant to data which can be expected to result from the program. A list of participants and their institutions is presented. Two solar flare paradigms were discussed during the meeting -- the importance of magnetic reconnection in flares and the applicability of numerical simulation results to solar flare studies.
Mann, D W
1996-01-01
This paper reviews the historical and conceptual development of theories concerning the nature of the self, highlighting both common themes and differences among representative theorists and their systems. The evolution of the concept of the self is traced from its ancient foundations in Vedic thought through its classical period (Socrates) and into the present century, where the work of James, Freud, Klein, Fairbairn, Sullivan, Winnicott, and Kohut illustrate the major modern refinements of the concept. The paper concludes with my own recent work toward a synthesis of these developments. PMID:9384992
Theory of ultracold superstrings
Snoek, Michiel; Vandoren, S.; Stoof, H. T. C.
2006-09-15
The combination of a vortex line in a one-dimensional optical lattice with fermions bound to the vortex core makes up an ultracold superstring. We give a detailed derivation of the way to make this supersymmetric string in the laboratory. In particular, we discuss the presence of a fermionic bound state in the vortex core and the tuning of the laser beams needed to achieve supersymmetry. Moreover, we discuss experimental consequences of supersymmetry and identify the precise supersymmetry in the problem. Finally, we make the mathematical connection with string theory.
Neutrinos: Theory and Phenomenology
Parke, Stephen
2013-10-22
The theory and phenomenology of neutrinos will be addressed, especially that relating to the observation of neutrino flavor transformations. The current status and implications for future experiments will be discussed with special emphasis on the experiments that will determine the neutrino mass ordering, the dominant flavor content of the neutrino mass eigenstate with the smallest electron neutrino content and the size of CP violation in the neutrino sector. Beyond the neutrino Standard Model, the evidence for and a possible definitive experiment to confirm or refute the existence of light sterile neutrinos will be briefly discussed.
NASA Technical Reports Server (NTRS)
Litvin, Faydor L.
1989-01-01
Basic mathematical problems on the theory of gearing are covered in this book, such as the necessary and sufficient conditions of envelope existence, relations between principal curvatures and directions for surfaces of mating gears. Also included are singularities of surfaces accompanied by undercutting the process of generation, the phenomena of envelope of lines of contact, and the principles for generation of conjugate surfaces. Special attention is given to the algorithms for computer aided simulation of meshing and tooth contact. This edition was complemented with the results of research recently performed by the author and his doctoral students. The book contains sample problems and also problems for the reader to solve.
Resolutions in Cotorsion Theories
NASA Astrophysics Data System (ADS)
Akinci, Karen; Alizade, Rafail
2010-11-01
We consider the λ- (μ-) and λ¯- (μ¯-) dimensions of modules taken under a cotorsion theory (F, C) satisfying the Hereditary Condition, and establish some inequalities between the dimensions of the modules of a short exact sequence, not necessarily Hom (
NASA Astrophysics Data System (ADS)
Stutzman, W. L.; Thiele, G. A.
Antenna fundamentals and definitions are examined, taking into account electromagnetic fundamentals, the solution of Maxwell's equations for radiation problems, the ideal dipole, the radiation pattern, directivity and gain, reciprocity and antenna pattern measurements, antenna impedance and radiation efficiency, antenna polarization, antennas in communication links and radar, and the receiving properties of antennas. Some simple radiating systems are considered along with arrays, line sources, wire antennas, broadband antennas, moment methods, and aperture antennas. High-frequency methods and aspects of antenna synthesis are discussed, giving attention to geometrical optics, physical optics, wedge diffraction theory, the ray-fixed coordinate system, the cylindrical parabolic antenna, and linear array methods.
Vector Theory of Ultrasonic Imaging
NASA Astrophysics Data System (ADS)
Gan, W. S.
So far, works on ultrasonic diffraction imaging are based on scalar theory of sound wave. This is not correct as sound has vector nature. But when sound propagates in solids, its vector nature has to be considered as polarization occurs and transverse wave as well as longitudinal wave will appear. Vector theory is especially needed when the obstacle size is smaller than the wavelength. We use the Smythe-Kirchhoff approach for the vector theory of diffraction. We derive the image formation theory based on the vector diffraction theory. The effect of polarization on acoustical imaging is discussed.
A Transversely Isotropic Thermoelastic Theory
NASA Technical Reports Server (NTRS)
Arnold, S. M.
1989-01-01
A continuum theory is presented for representing the thermoelastic behavior of composites that can be idealized as transversely isotropic. This theory is consistent with anisotropic viscoplastic theories being developed presently at NASA Lewis Research Center. A multiaxial statement of the theory is presented, as well as plane stress and plane strain reductions. Experimental determination of the required material parameters and their theoretical constraints are discussed. Simple homogeneously stressed elements are examined to illustrate the effect of fiber orientation on the resulting strain distribution. Finally, the multiaxial stress-strain relations are expressed in matrix form to simplify and accelerate implementation of the theory into structural analysis codes.
Endochronic theory of dynamic viscoplasticity
Lin, H.C.
1983-06-01
This report summarizes the work completed on a project concerned with engineering models in dyanmic plasticity. The concept of the endochronic theory of viscoplasticity and its subsequent improvement are discussed briefly. Applications and extensions of the theory to various dynamic problems are presented. In particular, the strain-rate effect in the improved endochronic theory and its application to wave propagation problems are discussed. Comparing the numerical results with other calculations and experimental data, it appears that endochronic theory provides a promising representation of realistic material behavior. At the same time endochronic theory is often numerically more efficient than other formulations.
Recent developments in superstring theory
Schwarz, John H.
1998-01-01
There have been many remarkable developments in our understanding of superstring theory in the past few years, a period that has been described as “the second superstring revolution.” In particular, what once appeared to be five distinct theories are now recognized to be different manifestations of a single (unique) underlying theory. Some of the evidence for this, based on dualities and the appearance of an eleventh dimension, is presented. Also, a specific proposal for the underlying theory, called “Matrix Theory,” is described. The presentation is intended primarily for the benefit of nonexperts. PMID:9501161
Recent developments in superstring theory.
Schwarz, J H
1998-03-17
There have been many remarkable developments in our understanding of superstring theory in the past few years, a period that has been described as "the second superstring revolution." In particular, what once appeared to be five distinct theories are now recognized to be different manifestations of a single (unique) underlying theory. Some of the evidence for this, based on dualities and the appearance of an eleventh dimension, is presented. Also, a specific proposal for the underlying theory, called "Matrix Theory," is described. The presentation is intended primarily for the benefit of nonexperts. PMID:9501161
Foundations of Satisfiability Modulo Theories
NASA Astrophysics Data System (ADS)
Tinelli, Cesare
Satisfiability Modulo Theories (SMT) studies methods for checking the (un)- satisfiability of first-order formulas with respect to a given logical theory T . Distinguishing features of SMT, as opposed to traditional theorem proving, are that the background theory T need not be finitely or even first-order axiomatizable, and that specialized inference methods are used for each theory of interest. By being theory-specific and restricting their language to certain classes of formulas (such as, typically but not exclusively, quantifier-free formulas), these methods can be implemented into solvers that are more efficient in practice than general-purpose theorem provers.
[Polyvagal theory and emotional trauma].
Leikola, Anssi; Mäkelä, Jukka; Punkanen, Marko
2016-01-01
According to the polyvagal theory, the autonomic nervous system can, in deviation from the conventional theory, be divided in three distinct parts that are in hierarchical relationship with each other. The most-primitive autonomic control results in depression of vital functions, the more evolved one in fighting or escape and the most evolved one in social involvement. Practical application of the polyvagal theory has resulted in positive results above all in the treatment of emotional trauma. in Finland, therapy of complex trauma is founded on the theory of structural dissociation of the personality, which together with the polyvagal theory forms a practical frame of reference for psychotherapeutic work. PMID:27044181
NASA Astrophysics Data System (ADS)
Forbes, T. G.; Linker, J. A.; Chen, J.; Cid, C.; Kóta, J.; Lee, M. A.; Mann, G.; Mikić, Z.; Potgieter, M. S.; Schmidt, J. M.; Siscoe, G. L.; Vainio, R.; Antiochos, S. K.; Riley, P.
This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1) CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling; (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section on CME initiation three contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can be released violently to drive CMEs. The third model assumes that CMEs can be directly driven by currents from below the photosphere. CMEs evolve considerably as they expand from the magnetically dominated lower corona into the advectively dominated solar wind. The section on evolution and propagation presents two approaches to the problem. One is primarily analytical and focuses on the key physical processes involved. The other is primarily numerical and illustrates the complexity of possible interactions between the CME and the ambient medium. The section on flux rope fitting reviews the accuracy and reliability of various methods. The section on shock formation considers the effect of the rapid decrease in the magnetic field and plasma density with height. Finally, in the section on particle acceleration and transport, some recent developments in the theory of diffusive particle acceleration at CME shocks are discussed. These include efforts to combine self-consistently the process of particle acceleration in the vicinity of the shock with the subsequent escape and transport of particles to distant regions.
NASA Astrophysics Data System (ADS)
Forbes, T. G.; Linker, J. A.; Chen, J.; Cid, C.; Kóta, J.; Lee, M. A.; Mann, G.; Mikić, Z.; Potgieter, M. S.; Schmidt, J. M.; Siscoe, G. L.; Vainio, R.; Antiochos, S. K.; Riley, P.
2006-03-01
This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1) CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling; (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section on CME initiation three contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can be released violently to drive CMEs. The third model assumes that CMEs can be directly driven by currents from below the photosphere. CMEs evolve considerably as they expand from the magnetically dominated lower corona into the advectively dominated solar wind. The section on evolution and propagation presents two approaches to the problem. One is primarily analytical and focuses on the key physical processes involved. The other is primarily numerical and illustrates the complexity of possible interactions between the CME and the ambient medium. The section on flux rope fitting reviews the accuracy and reliability of various methods. The section on shock formation considers the effect of the rapid decrease in the magnetic field and plasma density with height. Finally, in the section on particle acceleration and transport, some recent developments in the theory of diffusive particle acceleration at CME shocks are discussed. These include efforts to combine self-consistently the process of particle acceleration in the vicinity of the shock with the subsequent escape and transport of particles to distant regions.
Itoi, Eiji; Nagamoto, Hideaki; Sano, Hirotaka; Yamamoto, Nobuyuki; Kawakami, Jun
2016-08-12
The deadman theory is composed of two angles: θ1 and θ2, and it is recommended that both be less than or equal to 45°. Based on this theory, surgeons insert the anchor at 45°. However, the biomechanical studies show controversial data. We reviewed the original article and the biomechanical studies in the literature. We further performed three additional studies: 1) a finite element analysis to calculate the pullout strength of thread-less anchors inserted at 45°, 90°, and 135° to the polyurethane foam; 2) the same pullout test using thread-less anchors and the polyurethane foam; and 3) the same pullout test using metal threaded suture anchors and the simulated cortical bone. From the review and the additional studies, we came to the following explanations for the controversy: #1, the trigonometric calculation is not always applicable because of bone deformation; #2, insertion angle of 45° is the best for a thread-less anchor, but not for a threaded anchor; #3, θ1⩽45° is true, but it is not equivalent to inserting an anchor at 45°. In conclusion, insertion angle of 45° is the strongest for a thread-less anchor, but 90° is the strongest for a threaded anchor. The pullout strength depends on the inclination of the anchor, friction of the anchor-bone interface, and quality of the bone. PMID:27567773
NASA Astrophysics Data System (ADS)
Salam, Abdus; Wigner, E. P.
2010-03-01
Preface; List of contributors; Bibliography of P. A. M. Dirac; 1. Dirac in Cambridge R. J. Eden and J. C. Polkinghorne; 2. Travels with Dirac in the Rockies J. H. Van Vleck; 3. 'The golden age of theoretical physics': P. A. M. Dirac's scientific work from 1924 to 1933 Jagdish Mehra; 4. Foundation of quantum field theory Res Jost; 5. The early history of the theory of electron: 1897-1947 A. Pais; 6. The Dirac equation A. S. Wightman; 7. Fermi-Dirac statistics Rudolph Peierls; 8. Indefinite metric in state space W. Heisenberg; 9. On bras and kets J. M. Jauch; 10. The Poisson bracket C. Lanczos; 11. La 'fonction' et les noyaux L. Schwartz; 12. On the Dirac magnetic poles Edoardo Amadli and Nicola Cabibbo; 13. The fundamental constants and their time variation Freeman J. Dyson; 14. On the time-energy uncertainty relation Eugene P. Wigner; 15. The path-integral quantisation of gravity Abdus Salam and J. Strathdee; Index; Plates.
NASA Astrophysics Data System (ADS)
Griffiths, Robert B.
2001-11-01
Quantum mechanics is one of the most fundamental yet difficult subjects in physics. Nonrelativistic quantum theory is presented here in a clear and systematic fashion, integrating Born's probabilistic interpretation with Schrödinger dynamics. Basic quantum principles are illustrated with simple examples requiring no mathematics beyond linear algebra and elementary probability theory. The quantum measurement process is consistently analyzed using fundamental quantum principles without referring to measurement. These same principles are used to resolve several of the paradoxes that have long perplexed physicists, including the double slit and Schrödinger's cat. The consistent histories formalism used here was first introduced by the author, and extended by M. Gell-Mann, J. Hartle and R. Omnès. Essential for researchers yet accessible to advanced undergraduate students in physics, chemistry, mathematics, and computer science, this book is supplementary to standard textbooks. It will also be of interest to physicists and philosophers working on the foundations of quantum mechanics. Comprehensive account Written by one of the main figures in the field Paperback edition of successful work on philosophy of quantum mechanics
NASA Astrophysics Data System (ADS)
Aharony, Ofer; Komargodski, Zohar; Yankielowicz, Shimon
2016-04-01
We consider Euclidean Conformal Field Theories perturbed by quenched disorder, namely by random fluctuations in their couplings. Such theories are relevant for second-order phase transitions in the presence of impurities or other forms of disorder. Theories with quenched disorder often flow to new fixed points of the renormalization group. We begin with disorder in free field theories. Imry and Ma showed that disordered free fields can only exist for d > 4. For d > 4 we show that disorder leads to new fixed points which are not scale-invariant. We then move on to large- N theories (vector models or gauge theories in the `t Hooft limit). We compute exactly the beta function for the disorder, and the correlation functions of the disordered theory. We generalize the results of Imry and Ma by showing that such disordered theories exist only when disorder couples to operators of dimension Δ > d/4. Sometimes the disordered fixed points are not scale-invariant, and in other cases they have unconventional dependence on the disorder, including non-trivial effects due to irrelevant operators. Holography maps disorder in conformal theories to stochastic differential equations in a higher dimensional space. We use this dictionary to reproduce our field theory results. We also study the leading 1 /N corrections, both by field theory methods and by holography. These corrections are particularly important when disorder scales with the number of degrees of freedom.
Forgetting and remembering alienation theory.
Yuill, Chris
2011-01-01
Alienation theory has acted as the stimulus for a great deal of research and writing in the history of sociology. It has formed the basis of many sociological "classics" focused on the workplace and the experiences of workers, and has also been mobilized to chart wider social malaise and individual troubles. Alienation theory usage has, however, declined significantly since its heyday of the 1960s and 1970s. Here, the reasons why alienation theory was "forgotten" and what can be gained by "remembering" alienation theory are explored. to realize this ambition this article proceeds by (1) briefly visiting differing definitions of alienation theory, before charting its high point, and the various debates and tensions of the time, during the 1960s and 1970s; (2) analysing the reasons why alienation theory fell from grace from the 1980s onwards; (3) elaborating how and why alienation theory is still relevant for sociology and the wider social sciences today. PMID:21809508
Ooguri, H. |
1997-09-01
A low energy effective theory of parallel D(irichlet) branes is a gauge theory with sixteen supercharges, but one can consider a web of brane to realize situations with reduced number of supersymmetry. In this talk, the authors discusses four-dimensional theories with N = 1 and 2 supersymmetry (i.e. four and eight supercharges). In the case of theories with N = 2 supersymmetry, the exact description of the Coulomb branch is given by reinterpreting the web of branes as a configuration of a single fivebrane in the IIA theory. Recently the authors studied the case with N = 1 supersymmetry, and found that description in terms of the fivebrane in M Theory captures strong coupling dynamics of the N = 1 gauge theory in four dimensions. In particular, they found that the configuration of the fivebrane geometrically encodes information on the Affleck-Dine-Seiberg superpotential and the structure of the quantum moduli space of vacua.
[Shedding light on chaos theory].
Chou, Shieu-Ming
2004-06-01
Gleick (1987) said that only three twentieth century scientific theories would be important enough to continue be of use in the twenty-first century: The Theory of Relativity, Quantum Theory, and Chaos Theory. Chaos Theory has become a craze which is being used to forge a new scientific system. It has also been extensively applied in a variety of professions. The purpose of this article is to introduce chaos theory and its nursing applications. Chaos is a sign of regular order. This is to say that chaos theory emphasizes the intrinsic potential for regular order within disordered phenomena. It is to be hoped that this article will inspire more nursing scientists to apply this concept to clinical, research, or administrative fields in our profession. PMID:15211774
Relevance theory: pragmatics and cognition.
Wearing, Catherine J
2015-01-01
Relevance Theory is a cognitively oriented theory of pragmatics, i.e., a theory of language use. It builds on the seminal work of H.P. Grice(1) to develop a pragmatic theory which is at once philosophically sensitive and empirically plausible (in both psychological and evolutionary terms). This entry reviews the central commitments and chief contributions of Relevance Theory, including its Gricean commitment to the centrality of intention-reading and inference in communication; the cognitively grounded notion of relevance which provides the mechanism for explaining pragmatic interpretation as an intention-driven, inferential process; and several key applications of the theory (lexical pragmatics, metaphor and irony, procedural meaning). Relevance Theory is an important contribution to our understanding of the pragmatics of communication. PMID:26263065
Changing theories of change: strategic shifting in implicit theory endorsement.
Leith, Scott A; Ward, Cindy L P; Giacomin, Miranda; Landau, Enoch S; Ehrlinger, Joyce; Wilson, Anne E
2014-10-01
People differ in their implicit theories about the malleability of characteristics such as intelligence and personality. These relatively chronic theories can be experimentally altered, and can be affected by parent or teacher feedback. Little is known about whether people might selectively shift their implicit beliefs in response to salient situational goals. We predicted that, when motivated to reach a desired conclusion, people might subtly shift their implicit theories of change and stability to garner supporting evidence for their desired position. Any motivated context in which a particular lay theory would help people to reach a preferred directional conclusion could elicit shifts in theory endorsement. We examine a variety of motivated situational contexts across 7 studies, finding that people's theories of change shifted in line with goals to protect self and liked others and to cast aspersions on disliked others. Studies 1-3 demonstrate how people regulate their implicit theories to manage self-view by more strongly endorsing an incremental theory after threatening performance feedback or memories of failure. Studies 4-6 revealed that people regulate the implicit theories they hold about favored and reviled political candidates, endorsing an incremental theory to forgive preferred candidates for past gaffes but leaning toward an entity theory to ensure past failings "stick" to opponents. Finally, in Study 7, people who were most threatened by a previously convicted child sex offender (i.e., parents reading about the offender moving to their neighborhood) gravitated most to the entity view that others do not change. Although chronic implicit theories are undoubtedly meaningful, this research reveals a previously unexplored source of fluidity by highlighting the active role people play in managing their implicit theories in response to goals. PMID:25222649
Raby, S.; Walker, T.; Babu, K.S.; Baer, H.; Balantekin, A.B.; Barger, V.; Berezhiani, Z.; de Gouvea, A.; Dermisek, R.; Dolgov, A.; Fileviez Perez, P.; Gabadadze, G.; Gal, A.; Gondolo, P.; Haxton, W.; Kamyshkov, Y.; Kayser, B.; Kearns, E.; Kopeliovich, B.; Lande, K.; Marfatia, D.; /Kansas U. /Maryland U. /Northeastern U. /UC, Berkeley /LBL, Berkeley /Minnesota U. /SLAC /UC, Santa Cruz /SUNY, Stony Brook /Oklahoma State U. /Iowa State U. /Carnegie Mellon U.
2011-11-14
The scientific case for a Deep Underground Science and Engineering Laboratory [DUSEL] located at the Homestake mine in Lead, South Dakota is exceptional. The site of this future laboratory already claims a discovery for the detection of solar neutrinos, leading to a Nobel Prize for Ray Davis. Moreover this work provided the first step to our present understanding of solar neutrino oscillations and a chink in the armor of the Standard Model of particle physics. We now know, from several experiments located in deep underground experimental laboratories around the world, that neutrinos have mass and even more importantly this mass appears to fit into the framework of theories which unify all the known forces of nature, i.e. the strong, weak, electromagnetic and gravitational. Similarly, DUSEL can forge forward in the discovery of new realms of nature, housing six fundamental experiments that will test the frontiers of our knowledge: (1) Searching for nucleon decay (the decay of protons and neutrons predicted by grand unified theories of nature); (2) Searching for neutrino oscillations and CP violation by detecting neutrinos produced at a neutrino source (possibly located at Brookhaven National Laboratory and/or Fermi National Laboratory); (3) Searching for astrophysical neutrinos originating from the sun, from cosmic rays hitting the upper atmosphere or from other astrophysical sources, such a supernovae; (4) Searching for dark matter particles (the type of matter which does not interact electromagnetically, yet provides 24% of the mass of the Universe); (5) Looking for the rare process known as neutrino-less double beta decay which is predicted by most theories of neutrino mass and allows two neutrons in a nucleus to spontaneously change into two protons and two electrons; and (6) Searching for the rare process of neutron- anti-neutron oscillations, which would establish violation of baryon number symmetry. A large megaton water Cherenkov detector for neutrinos and
Gauge Coupling Unification in F-Theory Grand Unified Theories
Blumenhagen, Ralph
2009-02-20
We investigate gauge coupling unification for F-theory type IIB orientifold constructions of SU(5) grand unified theories (GUT) with gauge symmetry breaking via nontrivial hypercharge flux. This flux has the nontrivial effect that it splits the values of the three minimal supersymmetric standard model gauge couplings at the string scale, thus potentially spoiling the celebrated one-loop gauge coupling unification. It is shown how F-theory can evade this problem in a natural way.
Gauge coupling unification in F-theory grand unified theories.
Blumenhagen, Ralph
2009-02-20
We investigate gauge coupling unification for F-theory type IIB orientifold constructions of SU(5) grand unified theories (GUT) with gauge symmetry breaking via nontrivial hypercharge flux. This flux has the nontrivial effect that it splits the values of the three minimal supersymmetric standard model gauge couplings at the string scale, thus potentially spoiling the celebrated one-loop gauge coupling unification. It is shown how F-theory can evade this problem in a natural way. PMID:19257658
An Integrated Higgs Force Theory
NASA Astrophysics Data System (ADS)
Colella, Antonio
2016-03-01
An Integrated Higgs force theory (IHFT) was based on 2 key requirement amplifications: a matter particle/Higgs force was one and inseparable; a matter particle/Higgs force bidirectionally condensed/evaporated from/to super force. These were basis of 5 theories: particle creation, baryogenesis, superpartner/quark decays, spontaneous symmetry breaking, and stellar black holes. Our universe's 129 matter/force particles contained 64 supersymmetric Higgs particles; 9 transient matter particles/Higgs forces decayed to 8 permanent matter particles/Higgs forces; mass was given to a matter particle by its Higgs force and gravitons; and sum of 8 Higgs force energies of 8 permanent matter particles was dark energy. An IHFT's essence is the intimate physical relationships between 8 theories. These theories are independent because physicists in one theory worked independently of physicists in the other seven. An IHFT's premise is without sacrificing their integrities, 8 independent existing theories are replaced by 8 interrelated amplified theories. Requirement amplifications provide interfaces between the 8 theories. Intimate relationships between 8 theories including the above 5 and string, Higgs forces, and Super Universe are described. The sorting category selected was F. PARTICLES AND FIELDS (e.g., F1 Higgs Physics, F10 Alternative Beyond the Standard Model Physics, F11 Dark Sector Theories and Searches, and F12 Particle Cosmology).
NASA Technical Reports Server (NTRS)
Chudnovsky, A.
1987-01-01
A damage parameter is introduced in addition to conventional parameters of continuum mechanics and consider a crack surrounded by an array of microdefects within the continuum mechanics framework. A system consisting of the main crack and surrounding damage is called crack layer (CL). Crack layer propagation is an irreversible process. The general framework of the thermodynamics of irreversible processes are employed to identify the driving forces (causes) and to derive the constitutive equation of CL propagation, that is, the relationship between the rates of the crack growth and damage dissemination from one side and the conjugated thermodynamic forces from another. The proposed law of CL propagation is in good agreement with the experimental data on fatigue CL propagation in various materials. The theory also elaborates material toughness characterization.
NASA Technical Reports Server (NTRS)
Hsu, C.-H.; Lan, C. E.
1985-01-01
Wing rock is one type of lateral-directional instabilities at high angles of attack. To predict wing rock characteristics and to design airplanes to avoid wing rock, parameters affecting wing rock characteristics must be known. A new nonlinear aerodynamic model is developed to investigate the main aerodynamic nonlinearities causing wing rock. In the present theory, the Beecham-Titchener asymptotic method is used to derive expressions for the limit-cycle amplitude and frequency of wing rock from nonlinear flight dynamics equations. The resulting expressions are capable of explaining the existence of wing rock for all types of aircraft. Wing rock is developed by negative or weakly positive roll damping, and sustained by nonlinear aerodynamic roll damping. Good agreement between theoretical and experimental results is obtained.
Semistrict higher gauge theory
NASA Astrophysics Data System (ADS)
Jurčo, Branislav; Sämann, Christian; Wolf, Martin
2015-04-01
We develop semistrict higher gauge theory from first principles. In particular, we describe the differential Deligne cohomology underlying semistrict principal 2-bundles with connective structures. Principal 2-bundles are obtained in terms of weak 2-functors from the Čech groupoid to weak Lie 2-groups. As is demonstrated, some of these Lie 2-groups can be differentiated to semistrict Lie 2-algebras by a method due to Ševera. We further derive the full description of connective structures on semistrict principal 2-bundles including the non-linear gauge transformations. As an application, we use a twistor construction to derive superconformal constraint equations in six dimensions for a non-Abelian tensor multiplet taking values in a semistrict Lie 2-algebra.
Intermolecular perturbation theory
NASA Astrophysics Data System (ADS)
Hayes, I. C.; Hurst, G. J. B.; Stone, A. J.
The new intermolecular perturbation theory described in the preceding papers is applied to some van der Waals molecules. HeBe is used as a test case, and the perturbation method converges well at interatomic distances down to about 4 a0, giving results in excellent agreement with supermolecule calculations. ArHF and ArHCl have been studied using large basis sets, and the results agree well with experimental data. The ArHX configuration is favoured over the ArXH configuration mainly because of larger polarization and charge-transfer contributions. In NeH2 the equilibrium geometry is determined by a delicate balance between opposing effects; with a double-zeta-polarization basis the correct configuration is predicted.
Galton, D J
1998-01-01
With the recent developments in the Human Genome Mapping Project and the new technologies that are developing from it there is a renewal of concern about eugenic applications. Francis Galton (b1822, d1911), who developed the subject of eugenics, suggested that the ancient Greeks had contributed very little to social theories of eugenics. In fact the Greeks had a profound interest in methods of supplying their city states with the finest possible progeny. This paper therefore reviews the works of Plato (The Republic and Politics) and Aristotle (The Politics and The Athenian Constitution) which have a direct bearing on eugenic techniques and relates them to methods used in the present century. PMID:9752630
Towers of Gravitational Theories
NASA Astrophysics Data System (ADS)
Goldberger, Walter D.; Rothstein, Ira Z.
In this essay, we introduce a theoretical framework designed to describe black hole dynamics. The difficulties in understanding such dynamics stems from the proliferation of scales involved when one attempts to simultaneously describe all of the relevant dynamical degrees of freedom. These range from the modes that describe the black hole horizon, which are responsible for dissipative effects, to the long wavelength gravitational radiation that drains mechanical energy from macroscopic black hole bound states. We approach the problem from a Wilsonian point of view, by building a tower of theories of gravity each of which is valid at different scales. The methodology leads to multiple new results in diverse topics including phase transitions of Kaluza-Klein black holes and the interactions of spinning black hole in non-relativistic orbits. Moreover, our methods tie together speculative ideas regarding dualities for black hole horizons to real physical measurements in gravitational wave detectors.
Towers of gravitational theories
NASA Astrophysics Data System (ADS)
Goldberger, Walter D.; Rothstein, Ira Z.
2006-11-01
In this essay we introduce a theoretical framework designed to describe black hole dynamics. The difficulties in understanding such dynamics stems from the proliferation of scales involved when one attempts to simultaneously describe all of the relevant dynamical degrees of freedom. These range from the modes that describe the black hole horizon, which are responsible for dissipative effects, to the long wavelength gravitational radiation that drains mechanical energy from macroscopic black hole bound states. We approach the problem from a Wilsonian point of view, by building a tower of theories of gravity each of which is valid at different scales. The methodology leads to multiple new results in diverse topics including phase transitions of Kaluza-Klein black holes and the interactions of spinning black hole in non-relativistic orbits. Moreover, our methods tie together speculative ideas regarding dualities for black hole horizons to real physical measurements in gravitational wave detectors.
Galton, D J
1998-08-01
With the recent developments in the Human Genome Mapping Project and the new technologies that are developing from it there is a renewal of concern about eugenic applications. Francis Galton (b1822, d1911), who developed the subject of eugenics, suggested that the ancient Greeks had contributed very little to social theories of eugenics. In fact the Greeks had a profound interest in methods of supplying their city states with the finest possible progeny. This paper therefore reviews the works of Plato (The Republic and Politics) and Aristotle (The Politics and The Athenian Constitution) which have a direct bearing on eugenic techniques and relates them to methods used in the present century. PMID:9752630
Constrained sensitivity theory
Greenspan, E.; Williams, M.L.
1980-01-01
In sensitivity and uncertainty analysis of to-be-built reactors it is customary to use k-reset sensitivity functions - accounting for the combined effects of the change (or uncertainty) in the input data and of the alteration in some design variable applied to maintain criticality. Critical reactors are usually subjected to several constraints, such as power peaking factor and breeding ratio constraints, in addition to the criticality constraint. Perturbation theory formulations which can account, simultaneously, for several constraints both in critical reactors and in source driven systems (such as radiation shields and blankets of fusion devices) are presented. All the sensitivity and uncertainty analyses of source driven systems carried out so far used unconstrained sensitivity functions despite the fact that such systems can be also subjected to a variety of constraints.
NASA Technical Reports Server (NTRS)
Chudnovsky, A.
1984-01-01
A damage parameter is introduced in addition to conventional parameters of continuum mechanics and consider a crack surrounded by an array of microdefects within the continuum mechanics framework. A system consisting of the main crack and surrounding damage is called crack layer (CL). Crack layer propagation is an irreversible process. The general framework of the thermodynamics of irreversible processes are employed to identify the driving forces (causes) and to derive the constitutive equation of CL propagation, that is, the relationship between the rates of the crack growth and damage dissemination from one side and the conjugated thermodynamic forces from another. The proposed law of CL propagation is in good agreement with the experimental data on fatigue CL propagation in various materials. The theory also elaborates material toughness characterization.
Svrcek, Peter; Witten, Edward; /Princeton, Inst. Advanced Study
2006-06-09
In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.
Tribology theory versus experiment
NASA Technical Reports Server (NTRS)
Ferrante, John
1987-01-01
Tribology, the study of friction and wear of materials, has achieved a new interest because of the need for energy conservation. Fundamental understanding of this field is very complex and requires a knowledge of solid-state physics, material science, chemistry, and mechanical engineering. This paper is meant to be didactic in nature and outlines some of the considerations needed for a tribology research program. The approach is first to present a simple model, a field emission tip in contact with a flat surface, in order to elucidate important considerations, such as contact area, mechanical deformations, and interfacial bonding. Then examples from illustrative experiments are presented. Finally, the current status of physical theories concerning interfacial bonding are presented.
NASA Astrophysics Data System (ADS)
Cerveny, V.
2001-07-01
The seismic ray method plays an important role in seismology, seismic exploration, and in the interpretation of seismic measurements. Seismic Ray Theory presents the most comprehensive treatment of the method available. Many new concepts that extend the possibilities and increase the method's efficiency are included. The book has a tutorial character: derivations start with a relatively simple problem, in which the main ideas are easier to explain, and then advance to more complex problems. Most of the derived equations are expressed in algorithmic form and may be used directly for computer programming. This book will prove to be an invaluable advanced text and reference in all academic institutions in which seismology is taught or researched.
Elder, D
1984-06-01
The logic of genetic control of development may be based on a binary epigenetic code. This paper revises the author's previous scheme dealing with the numerology of annelid metamerism in these terms. Certain features of the code had been deduced to be combinatorial, others not. This paradoxical contrast is resolved here by the interpretation that these features relate to different operations of the code; the combinatiorial to coding identity of units, the non-combinatorial to coding production of units. Consideration of a second paradox in the theory of epigenetic coding leads to a new solution which further provides a basis for epimorphic regeneration, and may in particular throw light on the "regeneration-duplication" phenomenon. A possible test of the model is also put forward. PMID:6748695
Partition density functional theory
NASA Astrophysics Data System (ADS)
Nafziger, Jonathan
Partition density functional theory (PDFT) is a method for dividing a molecular electronic structure calculation into fragment calculations. The molecular density and energy corresponding to Kohn Sham density-functional theory (KS-DFT) may be exactly recovered from these fragments. Each fragment acts as an isolated system except for the influence of a global one-body 'partition' potential which deforms the fragment densities. In this work, the developments of PDFT are put into the context of other fragment-based density functional methods. We developed three numerical implementations of PDFT: One within the NWChem computational chemistry package using basis sets, and the other two developed from scratch using real-space grids. It is shown that all three of these programs can exactly reproduce a KS-DFT calculation via fragment calculations. The first of our in-house codes handles non-interacting electrons in arbitrary one-dimensional potentials with any number of fragments. This code is used to explore how the exact partition potential changes for different partitionings of the same system and also to study features which determine which systems yield non-integer PDFT occupations and which systems are locked into integer PDFT occupations. The second in-house code, CADMium, performs real-space calculations of diatomic molecules. Features of the exact partition potential are studied for a variety of cases and an analytical formula determining singularities in the partition potential is derived. We introduce an approximation for the non-additive kinetic energy and show how this quantity can be computed exactly. Finally a PDFT functional is developed to address the issues of static correlation and delocalization errors in approximations within DFT. The functional is applied to the dissociation of H2 + and H2.
F-theory and 2d (0, 2) theories
NASA Astrophysics Data System (ADS)
Schäfer-Nameki, Sakura; Weigand, Timo
2016-05-01
F-theory compactified on singular, elliptically fibered Calabi-Yau five-folds gives rise to two-dimensional gauge theories preserving N = (0 , 2) supersymmetry. In this paper we initiate the study of such compactifications and determine the dictionary between the geometric data of the elliptic fibration and the 2d gauge theory such as the matter content in terms of (0 , 2) superfields and their supersymmetric couplings. We study this setup both from a gauge-theoretic point of view, in terms of the partially twisted 7-brane theory, and provide a global geometric description based on the structure of the elliptic fibration and its singularities. Global consistency conditions are determined and checked against the dual M-theory compactification to one dimension. This includes a discussion of gauge anomalies, the structure of the Green-Schwarz terms and the Chern-Simons couplings in the dual M-theory supersymmetric quantum mechanics. Furthermore, by interpreting the resulting 2d (0 , 2) theories as heterotic worldsheet theories, we propose a correspondence between the geometric data of elliptically fibered Calabi-Yau five-folds and the target space of a heterotic gauged linear sigma-model (GLSM). In particular the correspondence between the Landau-Ginsburg and sigma-model phase of a 2d (0 , 2) GLSM is realized via different T-branes or gluing data in F-theory.
Applying Lakatos' Theory to the Theory of Mathematical Problem Solving.
ERIC Educational Resources Information Center
Nunokawa, Kazuhiko
1996-01-01
The relation between Lakatos' theory and issues in mathematics education, especially mathematical problem solving, is investigated by examining Lakatos' methodology of a scientific research program. (AIM)
Gauge Theories of Vector Particles
DOE R&D Accomplishments Database
Glashow, S. L.; Gell-Mann, M.
1961-04-24
The possibility of generalizing the Yang-Mills trick is examined. Thus we seek theories of vector bosons invariant under continuous groups of coordinate-dependent linear transformations. All such theories may be expressed as superpositions of certain "simple" theories; we show that each "simple theory is associated with a simple Lie algebra. We may introduce mass terms for the vector bosons at the price of destroying the gauge-invariance for coordinate-dependent gauge functions. The theories corresponding to three particular simple Lie algebras - those which admit precisely two commuting quantum numbers - are examined in some detail as examples. One of them might play a role in the physics of the strong interactions if there is an underlying super-symmetry, transcending charge independence, that is badly broken. The intermediate vector boson theory of weak interactions is discussed also. The so-called "schizon" model cannot be made to conform to the requirements of partial gauge-invariance.
Learning theory and intrapsychic conflict.
Gillett, E
1996-08-01
This paper is one in a series (Gillett, 1990, 1994) attempting to explore the implications of modern ideas about learning for psychoanalytic theories of treatment and pathogenesis. The key concept is that of learned expectations, which establishes links with Freud's 1926 theory of neurotic anxiety as caused by the expectation of danger. The new understanding of classical Pavlovian conditioning entails changes in the basic theory of intrapsychic conflict described in previous papers (1990, 1994). The relationship of learning theory to Freud's 1926 theory of intrapsychic conflict has received insufficient attention in the psychoanalytic literature because of insufficient familiarity with the repudiation of behaviourism by psychologists in favour of a representational theory of the mind. PMID:8876330
Conservation laws in embedding theory
NASA Astrophysics Data System (ADS)
Murillo, Oscar; Mustafaev, Alexander
2015-09-01
In this work is considered embedding theory, a theory in which independent variables which describe gravity are functions of the space-time embedding into a ten-dimensional pseudo-Euclidean space. Neother's theorem is used to find conservation laws for energy and angular momentum as a result from the action's invariance in relation to the rotation and translation of the system. The form of these conservation laws and their consequences depending on the different formulations of embedding theory is discussed. It is also analyzed a transition from embedding theory to a field theory in a flat space-time with a number of dimensions greater than four. The same procedure is followed in this case to find conservation laws, resulting in the solution of the problem of time present in Einstein's theory of general relativity.
Exploring gravitational theories beyond Horndeski
Gleyzes, Jérôme; Vernizzi, Filippo; Langlois, David; Piazza, Federico E-mail: langlois@apc.univ-partis7.fr E-mail: filippo.vernizzi@cea.fr
2015-02-01
We have recently proposed a new class of gravitational scalar-tensor theories free from Ostrogradski instabilities, in ref. [1]. As they generalize Horndeski theories, or ''generalized'' galileons, we call them G{sup 3}. These theories possess a simple formulation when the time hypersurfaces are chosen to coincide with the uniform scalar field hypersurfaces. We confirm that they contain only three propagating degrees of freedom by presenting the details of the Hamiltonian formulation. We examine the coupling between these theories and matter. Moreover, we investigate how they transform under a disformal redefinition of the metric. Remarkably, these theories are preserved by disformal transformations that depend on the scalar field gradient, which also allow to map subfamilies of G{sup 3} into Horndeski theories.
A succession of theories: purging redundancy from disturbance theory.
Pulsford, Stephanie A; Lindenmayer, David B; Driscoll, Don A
2016-02-01
The topics of succession and post-disturbance ecosystem recovery have a long and convoluted history. There is extensive redundancy within this body of theory, which has resulted in confusion, and the links among theories have not been adequately drawn. This review aims to distil the unique ideas from the array of theory related to ecosystem change in response to disturbance. This will help to reduce redundancy, and improve communication and understanding between researchers. We first outline the broad range of concepts that have developed over the past century to describe community change in response to disturbance. The body of work spans overlapping succession concepts presented by Clements in 1916, Egler in 1954, and Connell and Slatyer in 1977. Other theories describing community change include state and transition models, biological legacy theory, and the application of functional traits to predict responses to disturbance. Second, we identify areas of overlap of these theories, in addition to highlighting the conceptual and taxonomic limitations of each. In aligning each of these theories with one another, the limited scope and relative inflexibility of some theories becomes apparent, and redundancy becomes explicit. We identify a set of unique concepts to describe the range of mechanisms driving ecosystem responses to disturbance. We present a schematic model of our proposed synthesis which brings together the range of unique mechanisms that were identified in our review. The model describes five main mechanisms of transition away from a post-disturbance community: (i) pulse events with rapid state shifts; (ii) stochastic community drift; (iii) facilitation; (iv) competition; and (v) the influence of the initial composition of a post-disturbance community. In addition, stabilising processes such as biological legacies, inhibition or continuing disturbance may prevent a transition between community types. Integrating these six mechanisms with the functional
Invariants from classical field theory
Diaz, Rafael; Leal, Lorenzo
2008-06-15
We introduce a method that generates invariant functions from perturbative classical field theories depending on external parameters. By applying our methods to several field theories such as Abelian BF, Chern-Simons, and two-dimensional Yang-Mills theory, we obtain, respectively, the linking number for embedded submanifolds in compact varieties, the Gauss' and the second Milnor's invariant for links in S{sup 3}, and invariants under area-preserving diffeomorphisms for configurations of immersed planar curves.
Recent Progress in Superstring Theory
NASA Astrophysics Data System (ADS)
Schwarz, John H.
2002-12-01
Superstring theory has continued to develop at a rapid clip in the past few years. Following a quick review of some of the major discoveries prior to 1998, this talk focuses on a few of the more recent developments. The topics I have chosen to present are 1) the use of K-theory to classify conserved charges carried by D-branes; 2) tachyon condensation on unstable D-brane systems; and 3) an introduction to noncommutative field theories and their solitons.
Gravitational scalar-tensor theory
NASA Astrophysics Data System (ADS)
Naruko, Atsushi; Yoshida, Daisuke; Mukohyama, Shinji
2016-05-01
We consider a new form of gravity theories in which the action is written in terms of the Ricci scalar and its first and second derivatives. Despite the higher derivative nature of the action, the theory is ghost-free under an appropriate choice of the functional form of the Lagrangian. This model possesses 2 + 2 physical degrees of freedom, namely 2 scalar degrees and 2 tensor degrees. We exhaust all such theories with the Lagrangian of the form f(R,{({{\
NASA Astrophysics Data System (ADS)
Mišković, Olivera; Olea, Rodrigo
2011-01-01
Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, it extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.
The DBI action, higher-derivative supergravity, and flattening inflaton potentials
NASA Astrophysics Data System (ADS)
Bielleman, Sjoerd; Ibáñez, Luis E.; Pedro, Francisco G.; Valenzuela, Irene; Wieck, Clemens
2016-05-01
In string theory compactifications it is common to find an effective Lagrangian for the scalar fields with a non-canonical kinetic term. We study the effective action of the scalar position moduli of Type II D p-branes. In many instances the kinetic terms are in fact modified by a term proportional to the scalar potential itself. This can be linked to the appearance of higher-dimensional supersymmetric operators correcting the Kähler potential. We identify the supersymmetric dimension-eight operators describing the α' corrections captured by the D-brane Dirac-Born-Infeld action. Our analysis then allows an embedding of the D-brane moduli effective action into an {N}=1 supergravity formulation. The effects of the potential-dependent kinetic terms may be very important if one of the scalars is the inflaton, since they lead to a flattening of the scalar potential. We analyze this flattening effect in detail and compute its impact on the CMB observables for single-field inflation with monomial potentials.
Strong coupling BCS superconductivity and holography
NASA Astrophysics Data System (ADS)
Kalyana Rama, S.; Sarkar, Swarnendu; Sathiapalan, B.; Sircar, Nilanjan
2011-11-01
We attempt to give a holographic description of the microscopic theory of a BCS superconductor. Exploiting the analogy with chiral symmetry breaking in QCD we use the Sakai-Sugimoto model of two D8 branes in a D4 brane background with finite baryon number. In this case there is a new tachyonic instability which is plausibly the bulk analog of the Cooper pairing instability. We analyze the Yang-Mills approximation to the non-Abelian Dirac-Born-Infeld action. We give some exact solutions of the non-linear Yang-Mills equations in flat space and also give a stability analysis, showing that the instability disappears in the presence of an electric field. The holographic picture also suggests a dependence of T on the number density which is different from the usual (weak coupling) BCS. The flat space solutions are then generalized to curved space numerically and also, in an approximate way, analytically. This configuration should then correspond to the ground state of the boundary superconducting (superfluid) ground state. We also give some preliminary results on Green functions computations in the Sakai-Sugimoto model without any chemical potential.
Derivative self-interactions for a massive vector field
NASA Astrophysics Data System (ADS)
Beltrán Jiménez, Jose; Heisenberg, Lavinia
2016-06-01
In this work we revisit the construction of theories for a massive vector field with derivative self-interactions such that only the 3 desired polarizations corresponding to a Proca field propagate. We start from the decoupling limit by constructing healthy interactions containing second derivatives of the Stueckelberg field with itself and also with the transverse modes. The resulting interactions can then be straightforwardly generalized beyond the decoupling limit. We then proceed to a systematic construction of the interactions by using the Levi-Civita tensors. Both approaches lead to a finite family of allowed derivative self-interactions for the Proca field. This construction allows us to show that some higher order terms recently introduced as new interactions trivialize in 4 dimensions by virtue of the Cayley-Hamilton theorem. Moreover, we discuss how the resulting derivative interactions can be written in a compact determinantal form, which can also be regarded as a generalization of the Born-Infeld lagrangian for electromagnetism. Finally, we generalize our results for a curved background and give the necessary non-minimal couplings guaranteeing that no additional polarizations propagate even in the presence of gravity.
Effective actions of nongeometric five-branes
NASA Astrophysics Data System (ADS)
Chatzistavrakidis, Athanasios; Gautason, Fridrik Freyr; Moutsopoulos, George; Zagermann, Marco
2014-03-01
An interesting consequence of string dualities is that they reveal situations where the geometry of a string background appears to be globally ill defined, a phenomenon usually referred to as nongeometry. On the other hand, string theory contains extended objects with nontrivial monodromy around them, often dubbed defect or exotic branes in codimension-2. We determine and examine the worldvolume actions and the couplings of certain such branes. In particular, based on specific chains of T- and S-dualities, we derive the Dirac-Born-Infeld and Wess-Zumino actions, which describe the dynamics of type IIB five-branes as well as their couplings to the appropriate gauge potentials associated to mixed symmetry tensors. Based on these actions we discuss how these branes act as sources of nongeometric fluxes. In one case this flux is what is usually termed Q flux, associated to a T-fold compactification, while in the S-dual case a type of nongeometry related to the Ramond-Ramond sector is encountered.
Light by light diffraction in vacuum
Tommasini, Daniele; Michinel, Humberto
2010-07-15
We show that a laser beam can be diffracted by a more concentrated light pulse due to quantum vacuum effects. We compute analytically the intensity pattern in a realistic experimental configuration, and discuss how it can be used to measure the parameters describing photon-photon scattering in vacuum. In particular, we show that the quantum electrodynamics prediction can be detected in a single-shot experiment at future 100-PW lasers such as ELI or HIPER. On the other hand, if carried out at one of the present high-power facilities, such as OMEGA EP, this proposal can lead either to the discovery of nonstandard physics or to substantial improvement in the current limits by PVLAS collaboration on the photon-photon cross section at optical wavelengths. This example of manipulation of light by light is simpler to realize and more sensitive than existing, alternative proposals, and can also be used to test Born-Infeld theory or to search for axionlike or minicharged particles.
Comments on D-brane dynamics near NS5-branes
NASA Astrophysics Data System (ADS)
Sahakyan, David A.
2004-10-01
We study the properties of a D-brane in the presence of k NS5 branes. The Dirac-Born-Infeld action describing the dynamics of this D-brane is very similar to that of a non-BPS D-brane in ten dimensions. As the D-brane approaches the fivebranes, its equation of state approaches that of a pressureless fluid. In non-BPS D-brane case this is considered as an evidence for the decay of the D-brane into ``tachyon matter''. We show that in our case similar behavior is the consequence of the motion of the D-brane. In particular in the rest frame of the moving D-brane the equation of state is that of a usual D-brane, for which the pressure is equal to the energy density. We also compute the total cross-section for the decay of the D-brane into closed string modes and show that the emitted energy has a power like divergence for D0, D1 and D2 branes, while converges for higher dimensional D-branes. We also speculate on the possibility that the infalling D-brane describes a decaying defect in six dimensional Little String Theory.
Explicit integration of Friedmann's equation with nonlinear equations of state
NASA Astrophysics Data System (ADS)
Chen, Shouxin; Gibbons, Gary W.; Yang, Yisong
2015-05-01
In this paper we study the integrability of the Friedmann equations, when the equation of state for the perfect-fluid universe is nonlinear, in the light of the Chebyshev theorem. A series of important, yet not previously touched, problems will be worked out which include the generalized Chaplygin gas, two-term energy density, trinomial Friedmann, Born-Infeld, two-fluid models, and Chern-Simons modified gravity theory models. With the explicit integration, we are able to understand exactly the roles of the physical parameters in various models play in the cosmological evolution which may also offer clues to a profound understanding of the problems in general settings. For example, in the Chaplygin gas universe, a few integrable cases lead us to derive a universal formula for the asymptotic exponential growth rate of the scale factor, of an explicit form, whether the Friedmann equation is integrable or not, which reveals the coupled roles played by various physical sectors and it is seen that, as far as there is a tiny presence of nonlinear matter, conventional linear matter makes contribution to the dark matter, which becomes significant near the phantom divide line. The Friedmann equations also arise in areas of physics not directly related to cosmology. We provide some examples ranging from geometric optics and central orbits to soap films and the shape of glaciated valleys to which our results may be applied.
Closed string Ramond-Ramond proposed higher derivative interactions on fermionic amplitudes in IIB
NASA Astrophysics Data System (ADS)
Hatefi, Ehsan
2014-03-01
The complete form of the amplitude of one closed string Ramond-Ramond (RR), two fermionic strings and one scalar field in IIB superstring theory has been computed in detail. Deriving
Flavour fields in steady state: stress tensor and free energy
NASA Astrophysics Data System (ADS)
Banerjee, Avik; Kundu, Arnab; Kundu, Sandipan
2016-02-01
The dynamics of a probe brane in a given gravitational background is governed by the Dirac-Born-Infeld action. The corresponding open string metric arises naturally in studying the fluctuations on the probe. In Gauge-String duality, it is known that in the presence of a constant electric field on the worldvolume of the probe, the open string metric acquires an event horizon and therefore the fluctuation modes on the probe experience an effective temperature. In this article, we bring together various properties of such a system to a formal definition and a subsequent narration of the effective thermodynamics and the stress tensor of the corresponding flavour fields, also including a non-vanishing chemical potential. In doing so, we point out a potentially infinitely-degenerate scheme-dependence of regularizing the free energy, which nevertheless yields a universal contribution in certain cases. This universal piece appears as the coefficient of a log-divergence in free energy when a space-filling probe brane is embedded in AdS d+1-background, for d = 2, 4, and is related to conformal anomaly. For the special case of d = 2, the universal factor has a striking resemblance to the well-known heat current formula in (1 + 1)-dimensional conformal field theory in steady-state, which endows a plausible physical interpretation to it. Interestingly, we observe a vanishing conformal anomaly in d = 6.
Miskovic, Olivera; Olea, Rodrigo
2011-01-15
Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, it extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.
Consistency relation for the Lorentz invariant single-field inflation
Huang, Qing-Guo
2010-05-01
In this paper we compute the sizes of equilateral and orthogonal shape bispectrum for the general Lorentz invariant single-field inflation. The stability of field theory implies a non-negative square of sound speed which leads to a consistency relation between the sizes of orthogonal and equilateral shape bispectrum, namely f{sub NL}{sup orth.} ≤ −0.054f{sub NL}{sup equil.}. In particular, for the single-field Dirac-Born-Infeld (DBI) inflation, the consistency relation becomes f{sub NL}{sup orth.} = 0.070f{sub NL}{sup equil.} ≤ 0. These consistency relations are also valid in the mixed scenario where the quantum fluctuations of some other light scalar fields contribute to a part of total curvature perturbation on the super-horizon scale and may generate a local form bispectrum. A distinguishing prediction of the mixed scenario is τ{sub NL}{sup loc.} > ((6/5)f{sub NL}{sup loc.}){sup 2}. Comparing these consistency relations to WMAP 7yr data, there is still a big room for the Lorentz invariant inflation, but DBI inflation has been disfavored at more than 68% CL.
Soliton Theory and Its Applications
NASA Astrophysics Data System (ADS)
Gu, Chaohao
Soliton theory is an important branch of applied mathematics and mathematical physics. An active and productive field of research, it has important applications in fluid mechanics, nonlinear optics, classical and quantum fields theories etc. This book presents a broad view of soliton theory. It gives an expository survey of the most basic ideas and methods, such as physical background, inverse scattering, Backlünd transformations, finite-dimensional completely integrable systems, symmetry, Kac-moody algebra, solitons and differential geometry, numerical analysis for nonlinear waves, and gravitational solitons. Besides the essential points of the theory, several applications are sketched and some recent developments, partly by the authors and their collaborators, are presented.
Kreimer, Dirk . E-mail: kreimer@ihes.fr
2006-12-15
We exhibit the role of Hochschild cohomology in quantum field theory with particular emphasis on gauge theory and Dyson-Schwinger equations, the quantum equations of motion. These equations emerge from Hopf- and Lie algebra theory and free quantum field theory only. In the course of our analysis, we exhibit an intimate relation between the Slavnov-Taylor identities for the couplings and the existence of Hopf sub-algebras defined on the sum of all graphs at a given loop order, surpassing the need to work on single diagrams.
What's wrong with relativity theory?
NASA Astrophysics Data System (ADS)
Zhang, Meggie
2014-03-01
Relativity theory is the most successful theory in modern physics but insofar we have not be able to reconcile relativity theory and quantum physics. Through reevaluation results in literature we found hints leading to a new understanding of the basics of quantum physics. By reinterpretation quantum physic we have successfully conduced a photon-photon collision experiment which gives us support on our reinterpretation of quantum physics which in turn suggested relativity theory is in-complete and fell into a paradoxical trap. This helps us a new understanding of mass and gravity.
Nonstationary statistical theory for multipactor
Anza, S.; Vicente, C.; Gil, J.
2010-06-15
This work presents a new and general approach to the real dynamics of the multipactor process: the nonstationary statistical multipactor theory. The nonstationary theory removes the stationarity assumption of the classical theory and, as a consequence, it is able to adequately model electron exponential growth as well as absorption processes, above and below the multipactor breakdown level. In addition, it considers both double-surface and single-surface interactions constituting a full framework for nonresonant polyphase multipactor analysis. This work formulates the new theory and validates it with numerical and experimental results with excellent agreement.
Duality symmetries in string theory
Nunez, Carmen A.
1999-10-25
The search for a unified theory of quantum gravity and gauge interactions leads naturally to string theory. This field of research has received a revival of interest after the discovery of duality symmetries in recent years. We present a self contained account of some non-perturbative aspects of string theory which have been recently understood. The spectrum and interactions of the five consistent superstring theories in ten dimensions are recollected and the fundamental principles underlying this initial stage in the construction of the theory are briefly reviewed. We next discuss some evidences that these apparently different superstrings are just different aspects of one unique theory. The key to this development is given by the non-perturbative duality symmetries which have modified and improved our understanding of string dynamics in many ways. In particular, by relating the fundamental objects of one theory to solitons of another theory, they have unraveled the presence of extended objects in the theory which stand on an equal footing with strings. We introduce these higher dimensional objects, named D-branes, and discuss applications of D-brane physics.
Inflation from asymptotically safe theories
NASA Astrophysics Data System (ADS)
Nielsen, Niklas Grønlund; Sannino, Francesco; Svendsen, Ole
2015-05-01
We investigate models in which inflation is driven by an ultraviolet safe and interacting scalar sector stemming from a new class of nonsupersymmetric gauge field theories. These new theories, different from generic scalar models, are well defined to arbitrary short distances because of the existence of a controllable ultraviolet interacting fixed point. The scalar couplings at the ultraviolet fixed point and their overall running are predicted by the geometric structure of the underlying theory. We analyze the minimal and nonminimal coupling to gravity of these theories and the consequences for inflation. In the minimal coupling case the theory requires large nonperturbative quantum corrections to the quantum potential for the theory to agree with the data, while in the nonminimal coupling case the perturbative regime in the couplings of the theory is preferred. Requiring the theory to reproduce the observed amplitude of density perturbations constrains the geometric data of the theory such as the number of colors and flavors for generic values of the nonminimal coupling.
Canonical density matrix perturbation theory.
Niklasson, Anders M N; Cawkwell, M J; Rubensson, Emanuel H; Rudberg, Elias
2015-12-01
Density matrix perturbation theory [Niklasson and Challacombe, Phys. Rev. Lett. 92, 193001 (2004)] is generalized to canonical (NVT) free-energy ensembles in tight-binding, Hartree-Fock, or Kohn-Sham density-functional theory. The canonical density matrix perturbation theory can be used to calculate temperature-dependent response properties from the coupled perturbed self-consistent field equations as in density-functional perturbation theory. The method is well suited to take advantage of sparse matrix algebra to achieve linear scaling complexity in the computational cost as a function of system size for sufficiently large nonmetallic materials and metals at high temperatures. PMID:26764847
Introduction to Statistical Field Theory
NASA Astrophysics Data System (ADS)
Brézin, Edouard
2010-07-01
1. A few well-known basic results; 2. Introduction: order parameters, broken symmetries; 3. Examples of physical situations modelled by the Ising model; 4. A few results about the Ising model; 5. High temperature and low temperature expansions; 6. Some geometric problems related to phase transitions; 7. Phenomenological description of the critical behaviour; 8. Mean field theory; 9. Beyond mean field theory; 10. Introduction to the renormalization group; 11. Renormalization group for the φ4 theory; 12. Renormalized theory; 13. Goldstone modes; 14. Large n; Index.
Quantum set theory and applications
Rodriguez, E.
1984-01-01
The work of von Neumann tells us that the logic of quantum mechanics is not Boolenan. This suggests the formulation of a quantum theory of sets based on quantum logic much as modern set theory is based on Boolean logic. In the first part of this dissertation such a quantum set theory is developed. In the second part, quantum set theory is proposed as a universal language for physics. A quantum topology and the beginnings of a quantum geometry are developed in this language. Finally, a toy model is studied. It gives indications of possible lines for progress in this program.
Theories of Motivation--Borrowing the Best.
ERIC Educational Resources Information Center
Terpstra, David E.
1979-01-01
Five theories of motivation are discussed: Maslow's Need Hierarchy, Herzberg's dual-factor or motivation-hygiene theory, goal setting or task motivation, expectancy/valence-theory (also known as instrumentality theory, valence-instrumentality-expectancy theory, or expectancy theory), and reinforcement. (JH)
Theories of Serial Flow in Intergenerational Transfers.
ERIC Educational Resources Information Center
Cheal, David J.
1988-01-01
Presents and compares underlying assumptions of these theories as they might expand understanding of intergenerational transfers: social exchange theory, kin selection theory of altruism, human capital theory, social constructivist theory, and rational transfers theory. Recommends comparative studies to gain insight into strengths and weaknesses…
Management Theories and Broadcasting: A Handbook.
ERIC Educational Resources Information Center
Craig, J. Robert; Hindmarsh, Wayne A.
Today's contemporary management and motivation theories, as applied to the business of broadcasting, are the focus of the first section of this paper. It deals with the kinds and reactions of employees in broadcasting stations in relation to 11 motivational theories: (1) Theories X and Y, (2) Immaturity-Maturity Theory, (3) V Theory, (4) Z Theory,…
Shafi, Qaisar; Barr, Steven; Gaisser, Thomas; Stanev, Todor
2015-03-31
1. Executive Summary (April 1, 2012 - March 31, 2015) Title: Particle Theory, Particle Astrophysics and Cosmology Qaisar Shafi University of Delaware (Principal Investigator) Stephen M. Barr, University of Delaware (Co-Principal Investigator) Thomas K. Gaisser, University of Delaware (Co-Principal Investigator) Todor Stanev, University of Delaware (Co-Principal Investigator) The proposed research was carried out at the Bartol Research included Professors Qaisar Shafi Stephen Barr, Thomas K. Gaisser, and Todor Stanev, two postdoctoral fellows (Ilia Gogoladze and Liucheng Wang), and several graduate students. Five students of Qaisar Shafi completed their PhD during the period August 2011 - August 2014. Measures of the group’s high caliber performance during the 2012-2015 funding cycle included pub- lications in excellent refereed journals, contributions to working groups as well as white papers, and conference activities, which together provide an exceptional record of both individual performance as well as overall strength. Another important indicator of success is the outstanding quality of the past and current cohort of graduate students. The PhD students under our supervision regularly win the top departmental and university awards, and their publications records show excellence both in terms of quality and quantity. The topics covered under this grant cover the frontline research areas in today’s High Energy Theory & Phenomenology. For Professors Shafi and Barr they include LHC related topics including supersymmetry, collider physics, fl vor physics, dark matter physics, Higgs boson and seesaw physics, grand unifi and neutrino physics. The LHC two years ago discovered the Standard Model Higgs boson, thereby at least partially unlocking the secrets behind electroweak symmetry breaking. We remain optimistic that new and exciting physics will be found at LHC 14, which explain our focus on physics beyond the Standard Model. Professors Shafi continued his
Acquisition by Processing Theory: A Theory of Everything?
ERIC Educational Resources Information Center
Carroll, Susanne E.
2004-01-01
Truscott and Sharwood Smith (henceforth T&SS) propose a novel theory of language acquisition, "Acquisition by Processing Theory" (APT), designed to account for both first and second language acquisition, monolingual and bilingual speech perception and parsing, and speech production. This is a tall order. Like any theoretically ambitious…
Relevance Theory, Action Theory and Second Language Communication Strategies
ERIC Educational Resources Information Center
Foster-Cohen, Susan H.
2004-01-01
The discussion in this article offers a comparison between Relevance Theory as an account of human communication and Herbert Clark's (1996) sociocognitive Action Theory approach. It is argued that the differences are fundamental and impact analysis of all kinds of naturally occurring communicative data, including that produced by non-native…
Introduction to conformal field theory and string theory
Dixon, L.J.
1989-12-01
These lectures are meant to provide a brief introduction to conformal field theory (CFT) and string theory for those with no prior exposure to the subjects. There are many excellent reviews already available, and most of these go in to much more detail than I will be able to here. 52 refs., 11 figs.
The Theory Forum: Teaching Social Theory through Interactive Practice
ERIC Educational Resources Information Center
Osnowitz, Debra; Jenkins, Kathleen E.
2014-01-01
Common concerns in required theory courses are student disengagement when encountering difficult texts and hesitation to engage in theorizing. To address these challenges, we have developed an interactive exercise, which we call the theory forum. Students work in groups to develop questions from the perspective(s) of one or more theorists, and…
Theories and theorizers: a contextual approach to theories of cognition.
Barutta, Joaquín; Cornejo, Carlos; Ibáñez, Agustín
2011-06-01
An undisputable characteristic of cognitive science is its enormous diversity of theories. Not surprisingly, these often belong to different paradigms that focus on different processes and levels of analysis. A related problem is that researchers of cognition frequently seem to ascribe to incompatible approaches to research, creating a Tower of Babel of cognitive knowledge. This text presents a pragmatic model of meta-theoretical analysis, a theory conceived of to examine other theories, which allows cognitive theories to be described, integrated and compared. After a brief introduction to meta-theoretical analysis in cognitive science, the dynamic and structural components of a theory are described. The analysis of conceptual mappings between components and explanation strategies is also described, as well as the processes of intra-theory generalization and inter-theory comparison. The various components of the meta-theoretical model are presented with examples of different cognitive theories, mainly focusing on two current approaches to research: The dynamical approach to cognition and the computer metaphor of mind. Finally, two potential counter arguments to the model are presented and discussed. PMID:21344197
Double Exponential Relativity Theory Coupled Theoretically with Quantum Theory?
Montero Garcia, Jose de la Luz; Novoa Blanco, Jesus Francisco
2007-04-28
Here the problem of special relativity is analyzed into the context of a new theoretical formulation: the Double Exponential Theory of Special Relativity with respect to which the current Special or Restricted Theory of Relativity (STR) turns to be a particular case only.