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Sample records for born-infeld theory

  1. Wormholes in Einstein-Born-Infeld theory

    SciTech Connect

    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.

  2. Monopoles in non-Abelian Born-Infeld-Higgs theory and Born-Infeld collapse

    NASA Astrophysics Data System (ADS)

    Dyadichev, V. V.; Gal'Tsov, D. V.

    2002-06-01

    Regular magnetic monopoles in the non-Abelian Born-Infeld-Higgs theory are known to exist in the region of the field strength parameter β>βcr, bounded from below. Beyond this region, only pointlike (embedded Abelian) monopoles exist, and we show that the transition from the regular to singular structure is reminiscent of gravitational collapse. Near the threshold behavior is characterized by the rapidly increasing negative pressure, which typically arises in the high density non-Abelian Born-Infeld (NBI) matter. Another feature, shared by both the NBI and gravitating monopoles, is the existence of excited states, which can be thought of as bound states of monopoles and sphalerons. These are labeled by the number N of nodes of the Yang-Mills function. Their masses are greater than the mass of the ground state monopole, and they are expected to be unstable. The sequence of masses MN rapidly converges to the mass of the embedded Abelian solution with a constant Higgs boson. The ratio of the sphaleron size to that of the monopole grows with decreasing β, and, at the same time, both fall down until the solutions cease to exist, again exhibiting a collapse to the point-like monopole. The results are presented and compared both for the ordinary and the symmetrized trace NBI actions.

  3. 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.

  4. Screening of scalar fields in Dirac-Born-Infeld theory

    NASA Astrophysics Data System (ADS)

    Burrage, Clare; Khoury, Justin

    2014-07-01

    We study a new screening mechanism which is present in Dirac-Born-Infeld (DBI)-like theories. A scalar field with a DBI-like Lagrangian is minimally coupled to matter. In the vicinity of sufficiently dense sources, nonlinearities in the scalar dominate and result in an approximately constant acceleration on a test particle, thereby suppressing the scalar force relative to gravity. Unlike generic P(X) or chameleon theories, screening happens within the regime of validity of the effective field theory thanks to the DBI symmetry. We derive an exact form for the field profile around multiple sources and determine the constraints on the theory parameters from tests of gravity. Perturbations around the spherically-symmetric background propagate superluminally, but we argue for a chronology protection analogous to Galileons. This is the first example of a screening mechanism for which quantum corrections to the theory are under control and exact solutions to cosmological N-body problems can be found.

  5. 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.

  6. Corrected Article: Wormholes in Einstein-Born-Infeld theory [Phys. Rev. D 80, 104033 (2009)

    SciTech Connect

    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.

  7. Analysis of regularizing properties of nonlinear electrodynamics in the Einstein-Born-Infeld theory

    SciTech Connect

    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.

  8. 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.

  9. 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.

  10. A survey of solutions in a gravitational Born-Infeld theory

    SciTech Connect

    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.

  11. 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.

  12. Born-Infeld corrections to Coulombian interactions.

    PubMed

    Ferraro, Rafael; Lipchak, María Evangelina

    2008-04-01

    Two-dimensional Born-Infeld electrostatic fields behaving as the superposition of two pointlike charges in the linearized (Maxwellian) limit are investigated by means of a nonholomorphic mapping of the complex plane. The changes in the Coulombian interaction between two charges in Born-Infeld theory are computed. Remarkably, the force between equal charges goes to zero as they approach each other.

  13. Born-Infeld/gravity correspondence

    NASA Astrophysics Data System (ADS)

    Grignani, Gianluca; Harmark, Troels; Marini, Andrea; Orselli, Marta

    2016-09-01

    In this paper we explore the correspondence between four-dimensional Born-Infeld theory and five-dimensional classical gravity. The Born-Infeld theory side corresponds to the low-energy effective theory for open strings ending on coincident D3-branes in a (slowly varying) background Kalb-Ramond field, including all higher-derivative corrections. On the gravity side one has the gravitational (closed-string) description of D3-branes in the same background Kalb-Ramond field and the correspondence is thus a consequence of the open/closed-string duality. According to the correspondence the gravity side provides a description of the strong coupling limit of Born-Infeld theory. This is a correspondence between effective theories in a similar sense as in the fluid/gravity correspondence. We match the Born-Infeld and gravity sides up to, and including, two-derivative corrections. To this end, we find a new gravity solution for D3-branes with flat embedding in the background of an arbitrary constant background Kalb-Ramond field and show that there are no two-derivative corrections to this for a slowly varying Kalb-Ramond field.

  14. 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.

  15. 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.

  16. Black holes in Born-Infeld extended new massive gravity

    SciTech Connect

    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.

  17. 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.

  18. Skyrmions from a Born-Infeld action

    NASA Astrophysics Data System (ADS)

    Dion, B.; Marleau, L.; Simon, G.

    1996-02-01

    We consider geometrically motivated Higgs sector solitons based on a general covariant kinetic term proposed originally by Born and Infeld. We introduce this new term by generalizing the Born-Infeld action to a non-Abelian SU(2) gauge theory and by using the hidden gauge symmetry formalism. The static and stability properties of the solitons are then analyzed and compared with Skyrme-like models.

  19. Anisotropy in Born-Infeld brane cosmology

    SciTech Connect

    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.

  20. Nonsingular promises from Born-Infeld gravity.

    PubMed

    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

  1. 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.

  2. Born-Infeld gravity in three dimensions

    SciTech Connect

    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.

  3. Born-Infeld cosmology with scalar Born-Infeld matter

    NASA Astrophysics Data System (ADS)

    Jana, Soumya; Kar, Sayan

    2016-09-01

    Cosmology in Eddington-inspired Born-Infeld gravity is investigated using a scalar Born-Infeld field (e.g. tachyon condensate) as matter. In this way, both in the gravity and matter sectors we have Born-Infeld-like structures characterized by their actions and via two separate constants, κ and αT2 , respectively. With a particular choice of the form of ϕ ˙ (the time derivative of the Born-Infeld scalar), analytical cosmological solutions are found. Thereafter, we explore some of the unique features of the corresponding cosmological spacetimes. For κ >0 , our solution has a de Sitter-like expansion both at early and late times, with an intermediate deceleration sandwiched between the accelerating phases. On the other hand, when κ <0 , the initial de Sitter phase is replaced by a bounce. Our solutions, at late time, fit well with available supernova data—a fact we demonstrate explicitly. The estimated properties of the Universe obtained from the fitting of the κ >0 solution are as good as in Λ CDM cosmology. However, the κ <0 solution has to be discarded due to the occurrence of a bounce at an unacceptably low redshift.

  4. Cosmic String Global Superconducting Dirac Born Infeld

    NASA Astrophysics Data System (ADS)

    Ikrima, Ika; Ramadhan, Handhika S.; Mart, Terry

    2016-08-01

    Superconducting cosmic string possibly plays an important role in the formation of the universe structure. The physics of this phenomenon has been explored by studying the field theory in the string interior. Numerical solutions of superconducting strings with all relevant fields are presented in this paper. The field is constructed from a generalization of the usual field theory of superconducting global string, but the kinetic term consists of the Dirac Born Infeld (DBI). Some changes in the characteristic of the superconducting string DBI from the usual superconducting string case have been observed. The observation includes physical mechanism of all related fields.

  5. Non-Abelian Born Infeld action, geometry and supersymmetry

    NASA Astrophysics Data System (ADS)

    Julio Cirilo-Lombardo, Diego

    2005-12-01

    In this work, we propose a new non-Abelian generalization of the Born Infeld Lagrangian. It is based on a geometrical property of the Abelian Born Infeld Lagrangian in its determinantal form. Our goal is to extend the Abelian second-type Born Infeld action to the non-Abelian form preserving this geometrical property, which permits us to compute the generalized volume element as a linear combination of the components of metric and the Yang Mills energy momentum tensors. Under the BPS-like condition, the action proposed reduces to that of the Yang Mills theory, independently of the gauge group. New instanton-wormhole solution and static and spherically symmetric solution in curved spacetime for an SU(2) isotopic ansatz are solved and the N= 1 supersymmetric extension of the model is performed.

  6. Born-Infeld inspired bosonic action in a noncommutative geometry

    SciTech Connect

    Serie, Emmanuel; Masson, Thierry; Kerner, Richard

    2004-09-15

    The Born-Infeld Lagrangian for non-Abelian gauge theory is adapted to the case of the generalized gauge fields arising in noncommutative matrix geometry. Basic properties of static and time-dependent solutions of the scalar sector of this model are investigated.

  7. 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.

  8. 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.

  9. 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.

  10. Extended phase space thermodynamics and P- V criticality: Brans-Dicke-Born-Infeld vs. Einstein-Born-Infeld-dilaton black holes

    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.

  11. Testing Born-Infeld electrodynamics in waveguides.

    PubMed

    Ferraro, Rafael

    2007-12-01

    Waveguides can be employed to test nonlinear effects in electrodynamics. We solve Born-Infeld equations for TE waves in a rectangular waveguide. We show that the energy velocity acquires a dependence on the amplitude, and harmonic components appear as a consequence of the nonlinear behavior.

  12. Surface singularities in Eddington-inspired Born-Infeld gravity.

    PubMed

    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.

  13. Surface singularities in Eddington-inspired Born-Infeld gravity.

    PubMed

    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

  14. Parallel-plate and spherical capacitors in Born-Infeld electrostatics: An analytical study

    NASA Astrophysics Data System (ADS)

    Moayedi, S. K.; Shafabakhsh, M.

    2016-03-01

    In 1934, Max Born and Leopold Infeld suggested and developed a nonlinear modification of Maxwell electrodynamics, in which the electrostatic self-energy of an electron was a finite value. In this paper, after a brief introduction to Lagrangian formulation of Born-Infeld electrodynamics with an external source, the explicit forms of Gauss's law and the electrostatic energy density in Born-Infeld theory are obtained. The capacitance and the stored electrostatic energy for a parallel-plate and spherical capacitors are computed in the framework of Born-Infeld electrostatics. We show that the usual relations U=1/2C_{Maxwell}(triangle φ)2 and U=q2/2C_{Maxwell} are not valid for a capacitor in Born-Infeld electrostatics. Numerical estimations in this research show that the nonlinear corrections to the capacitance and the stored electrostatic energy for a capacitor in Born-Infeld electrostatics are considerable when the potential difference between the plates of a capacitor is very large.

  15. The Born-Infeld vortices induced from a generalized Higgs mechanism

    NASA Astrophysics Data System (ADS)

    Han, Xiaosen

    2016-04-01

    We construct self-dual Born-Infeld vortices induced from a generalized Higgs mechanism. Two specific models of the theory are of focused interest where the Higgs potential is either of a |φ|4- or |φ|6-type. For the |φ|4-model, we obtain a sharp existence and uniqueness theorem for doubly periodic and planar vortices. For doubly periodic solutions, a necessary and sufficient condition for the existence is explicitly derived in terms of the vortex number, the Born-Infeld parameter, and the size of the periodic lattice domain. For the |φ|6-model, we show that both topological and non-topological vortices are present. This new phenomenon distinguishes the model from the classical Born-Infeld-Higgs theory studied earlier in the literature. A series of results regarding doubly periodic, topological, and non-topological vortices in the |φ|6-model are also established.

  16. 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.

  17. On the Electrostatic Born-Infeld Equation with Extended Charges

    NASA Astrophysics Data System (ADS)

    Bonheure, Denis; d'Avenia, Pietro; Pomponio, Alessio

    2016-09-01

    In this paper, we deal with the electrostatic Born-Infeld equation -operatorname{div} (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.

  18. 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.

  19. Cascading dust inflation in Born-Infeld gravity

    SciTech Connect

    Jiménez, Jose Beltrán; Heisenberg, Lavinia; Olmo, Gonzalo J.; Ringeval, Christophe E-mail: lavinia.heisenberg@eth-its.ethz.ch E-mail: christophe.ringeval@uclouvain.be

    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.

  20. Extremal Einstein-Born-Infeld black holes in dilaton gravity

    NASA Astrophysics Data System (ADS)

    Rad, Masoud Sepehri; Hendi, Seyed Hossein; Matsuno, Ken; Sheykhi, Ahmad

    2015-12-01

    Motivated by considerable interests of Myers-Perry black holes, we employ the perturbative method to obtain a family of extremal charged rotating black hole solutions in odd dimensional Einstein-Born-Infeld-dilaton gravity. We start with an extremal Myers-Perry black hole with equal angular momenta, and then by adding the dilaton field and the nonlinear Born-Infeld electrodynamics, we find an extremal nonlinearly charged rotating black holes. The perturbative parameter is assumed to be the electric charge q and the perturbations are performed up to the third order. We then study the physical properties of these Born-Infeld-dilaton black holes. In particular, we show that the perturbative parameter, q, the dilaton coupling constant, α, and the Born-Infeld parameter, β, modify the Smarr formula and the values of the gyromagnetic ratio of the extremal charged rotating black holes.

  1. Born-Infeld gravity with a unique vacuum and a massless graviton

    NASA Astrophysics Data System (ADS)

    Güllü, Ibrahim; Şişman, Tahsin ćaǧrı; Tekin, Bayram

    2015-11-01

    We construct an n -dimensional Born-Infeld-type gravity theory that has the same properties as Einstein's gravity in terms of the vacuum and particle content: Namely, the theory has a unique viable vacuum (maximally symmetric solution) and a single massless unitary spin-2 graviton about this vacuum. The Born-Infeld gravity, in some sense, is the most natural, minimal generalization of Einstein's gravity with a better UV behavior and hence is a potentially less singular theory at small distances. The Gauss-Bonnet combination plays a nontrivial role in the construction of the theory. As an extreme example, we consider the infinite-dimensional limit where an interesting exponential gravity arises.

  2. 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.

  3. New Born-Infeld and Dp-brane actions under 2-metric and 3-metric prescriptions

    SciTech Connect

    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.

  4. 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.

  5. 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.

  6. 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.

  7. Born-Infeld gravity with a massless graviton in four dimensions

    NASA Astrophysics Data System (ADS)

    Güllü, Ibrahim; Şişman, Tahsin ćaǧrı; Tekin, Bayram

    2015-02-01

    We construct Born-Infeld (BI) type gravity theories which describe tree-level unitary (nonghost and nontachyonic) massless spin-2 modes around their maximally symmetric vacua in four dimensions. Building unitary BI actions around flat vacuum is straightforward, but this is a complicated task around (anti)-de Sitter backgrounds. In this work, we solve the issue and give details of constructing perturbatively viable determinantal BI theories. It is interesting that the Gauss-Bonnet combination, which is a total derivative in four dimensions, plays an important role in the construction of viable BI theories.

  8. Coulomb field scattering in Born-Infeld electrodynamics

    SciTech Connect

    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.

  9. Magnetic branes in third order Lovelock-Born-Infeld gravity

    SciTech Connect

    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.

  10. 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.

  11. Modified Eddington-inspired-Born-Infeld gravity with a trace term

    DOE PAGESBeta

    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

  12. Holographic thermalization with a chemical potential from Born-Infeld electrodynamics

    NASA Astrophysics Data System (ADS)

    Camilo, Giancarlo; Cuadros-Melgar, Bertha; Abdalla, Elcio

    2015-02-01

    The problem of holographic thermalization in the framework of Einstein gravity coupled to Born-Infeld nonlinear electrodynamics is investigated. We use equal time two-point correlation functions and expectation values of Wilson loop operators in the boundary quantum field theory as probes of thermalization, which have dual gravity descriptions in terms of geodesic lengths and minimal area surfaces in the bulk spacetime. The full range of values of the chemical potential per temperature ratio μ/T on the boundary is explored. The numerical results show that the effect of the charge on the thermalization time is similar to the one obtained with Maxwell electrodynamics, namely the larger the charge the later thermalization occurs. The Born-Infeld parameter, on the other hand, has the opposite effect: the more nonlinear the theory is, the sooner it thermalizes. We also study the thermalization velocity and how the parameters affect the phase transition point separating the thermalization process into an accelerating phase and a decelerating phase.

  13. 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.

  14. 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.

  15. 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 aBorn-Infeld black hole with outer and inner horizons. Similarly, the effect of β on the infinite redshift surface and in turn on the ergo-region is also included. It is well known that a black hole can cast a shadow as an optical appearance due to its strong gravitational field. We also investigate the shadow cast by the both static and rotating Einstein-Born-Infeld black hole and demonstrate that the null geodesic equations can be integrated, which 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 shadow of an Einstein-Born-Infeld black hole is slightly smaller than for the Reissner-Nordstrom black hole, which consists of concentric circles, for different values of the Born-Infeld parameter β , whose radius decreases with increase of the value of the parameter β . Finally, we have studied observable distortion parameter for shadow of the rotating Einstein-Born-Infeld black hole.

  16. 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.

  17. The virial theorem in Eddington-Born-Infeld gravity

    SciTech Connect

    Santos, Noelia S.; Santos, Janilo E-mail: janilo@dfte.ufrn.br

    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.

  18. 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.

  19. Holographic superconductors in Gauss-Bonnet gravity with Born-Infeld electrodynamics

    SciTech Connect

    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.

  20. Eddington-inspired Born-Infeld gravity: nuclear physics constraints and the validity of the continuous fluid approximation

    SciTech Connect

    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.

  1. 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.

  2. Topological black holes in Lovelock-Born-Infeld gravity

    SciTech Connect

    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.

  3. 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.

  4. Born-Infeld and charged black holes with non-linear source in f(T) gravity

    NASA Astrophysics Data System (ADS)

    Junior, Ednaldo L. B.; Rodrigues, Manuel E.; Houndjo, Mahouton J. S.

    2015-06-01

    We investigate f(T) theory coupled with a nonlinear source of electrodynamics, for a spherically symmetric and static spacetime in 4D. We re-obtain the Born-Infeld and Reissner-Nordstrom-AdS solutions. We generalize the no-go theorem for any content that obeys the relationship Script T00=Script T11 for the energy-momentum tensor and a given set of tetrads. Our results show new classes of solutions where the metrics are related through b(r)=-Na(r). We do the introductory analysis showing that solutions are that of asymptotically flat black holes, with a singularity at the origin of the radial coordinate, covered by a single event horizon. We also reconstruct the action for this class of solutions and obtain the functional form f(T)=f0(-T)(N+3)/[2(N+1)] and Script LNED=Script L0(-F)(N+3)/[2(N+1)]. Using the Lagrangian density of Born-Infeld, we obtain a new class of charged black holes where the action reads f(T)=-16βBI[1-√1+(T/4βBI)].

  5. Born-Infeld and charged black holes with non-linear source in f(T) gravity

    SciTech Connect

    Junior, Ednaldo L.B.; Rodrigues, Manuel E.; Houndjo, Mahouton J.S. E-mail: esialg@gmail.com

    2015-06-01

    We investigate f(T) theory coupled with a nonlinear source of electrodynamics, for a spherically symmetric and static spacetime in 4D. We re-obtain the Born-Infeld and Reissner-Nordstrom-AdS solutions. We generalize the no-go theorem for any content that obeys the relationship T{sup 0}{sub 0}=T{sup 1}{sub 1} for the energy-momentum tensor and a given set of tetrads. Our results show new classes of solutions where the metrics are related through b(r)=−Na(r). We do the introductory analysis showing that solutions are that of asymptotically flat black holes, with a singularity at the origin of the radial coordinate, covered by a single event horizon. We also reconstruct the action for this class of solutions and obtain the functional form f(T)=f{sub 0}(−T){sup (N+3)/[2(N+1)]} and L{sub NED}=L{sub 0}(−F){sup (N+3)/[2(N+1)]}. Using the Lagrangian density of Born-Infeld, we obtain a new class of charged black holes where the action reads f(T)=−16β{sub BI}[1−√1+(T/4β{sub BI})].

  6. Einstein-Born-Infeld black holes with a scalar hair in three dimensions

    NASA Astrophysics Data System (ADS)

    Mazharimousavi, S. Habib; Halilsoy, M.

    2015-09-01

    We present black hole solutions in (2+1)-dimensional Einstein’s theory of gravity coupled with Born-Infeld (BI) nonlinear electrodynamic and a massless self-interacting scalar field. The model has five free parameters: mass M, cosmological constant ℓ, electric q and scalar r0 charges and BI parameter β. To attain exact solution for such a highly nonlinear system we adjust, i.e. finely tune, the parameters of the theory with the integration constants. In the limit β → 0, we recover the results of Einstein-Maxwell-Scalar theory, obtained before. The self-interacting potential admits finite minima apt for the vacuum contribution. Hawking temperature of the model is investigated versus properly tuned parameters. By employing this tuned-solution as basis, we obtain also a dynamic solution which in the proper limit admits the known solution in Einstein gravity coupled with self-interacting scalar field. Finally, we establish the equations of a general scalar-tensor field coupled to nonlinear electrodynamics (NED) field in 2+1 dimensions without searching for exact solutions.

  7. Born-Infeld Black Holes Coupled to a Massive Scalar Field

    NASA Astrophysics Data System (ADS)

    Georgieva, Daniela A.; Stefanov, Ivan Zh.; Yazadjiev, Stoytcho S.; Todorov, Michail D.

    Born-Infeld black holes in the scalar-tensor theories of gravity with massless scalar field have been recently obtained [I. Stefanov, S. Yazadjiev and M. Todorov, Phys. Rev. D 75 (2007) 084036; Mod. Phys. Lett. A. 23(34) (2008) 2915; Class. Quantum Gravity 26 (2009) 015006]. The aim of the current paper is to study the effect of the inclusion of a potential for the scalar field in the theory, through a combination of analytical techniques and numerical methods. The black holes coupled to a massive scalar field have richer causal structure in comparison to the massless scalar field case. In the former case, the black holes may have a second, inner horizon. The presence of potential for the scalar field allows the existence of extremal black holes for certain values of the mass of the scalar field and the magnetic (electric) charge of the black hole. The solutions are stable against spherically symmetric perturbations. Arguments in favor of the general stability of the solutions coming from the application of the "turning point" method are also presented.

  8. 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.

  9. 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

  10. Thermodynamics of Einstein-Born-Infeld black holes in three dimensions

    SciTech Connect

    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)

  11. Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-Infeld

    SciTech Connect

    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.

  12. Black hole solutions in functional extensions of Born-Infeld gravity

    NASA Astrophysics Data System (ADS)

    Bambi, Cosimo; Rubiera-Garcia, D.; Wang, Yixu

    2016-09-01

    We consider electrovacuum black hole spacetimes in classical extensions of Eddington-inspired Born-Infeld gravity. By rewriting the Born-Infeld action as the square root of the determinant of a matrix Ω ^ , we consider the family of models f (|Ω ^|) and study black hole solutions for a power-law family of models labeled by a simple parameter. We show how the innermost structure of the corresponding black holes is modified as compared to their general relativity counterparts, discussing in which cases a wormhole structure replaces the pointlike singularity. We go forward to argue that in such cases a geodesically complete and, thus, nonsingular spacetime is present, despite the existence of curvature divergences at the wormhole throat.

  13. An extended magnetostatic Born-Infeld model with a concave lower order term

    SciTech Connect

    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.

  14. Born-Infeld AdS black holes as heat engines

    NASA Astrophysics Data System (ADS)

    Johnson, Clifford V.

    2016-07-01

    We study the efficiency of heat engines that perform mechanical work via the pdV terms present in the first law in extended gravitational thermodynamics. We use charged black holes as the working substance, for a particular choice of engine cycle. The context is Einstein gravity with negative cosmological constant and a Born-Infeld nonlinear electrodynamics sector. We compare the results for these ‘holographic’ heat engines to previous results obtained for Einstein-Maxwell black holes, and for the case where there is a Gauss-Bonnet sector.

  15. Dark energy as a Born-Infeld gauge interaction violating the equivalence principle.

    PubMed

    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

  16. Dark energy as a Born-Infeld gauge interaction violating the equivalence principle.

    PubMed

    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.

  17. Thermodynamics of rotating black branes in (n+1)-dimensional Einstein-Born-Infeld gravity

    SciTech Connect

    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.

  18. Thermodynamics of black holes in (n+1)-dimensional Einstein-Born-Infeld-dilaton gravity

    SciTech Connect

    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.

  19. 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.

  20. Formation of caustics in Dirac-Born-Infeld type scalar field systems

    SciTech Connect

    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

  1. 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.

  2. D-branes in generalized geometry and Dirac-Born-Infeld action

    NASA Astrophysics Data System (ADS)

    Asakawa, T.; Sasa, S.; Watamura, S.

    2012-10-01

    The purpose of this paper is to formulate the Dirac-Born-Infeld (DBI) action in a framework of generalized geometry and clarify its symmetry. A D-brane is defined as a Dirac structure where scalar fields and gauge field are treated on an equal footing in a static gauge. We derive generalized Lie derivatives corresponding to the diffeomorphism and B- field gauge transformations and show that the DBI action is invariant under non-linearly realized symmetries for all types of diffeomorphisms and B-field gauge transformations. Consequently, we can interpret not only the scalar field but also the gauge field on the D-brane as the generalized Nambu-Goldstone boson.

  3. Asymptotic properties of a supposedly regular (Dirac-Born-Infeld) modification of general relativity

    SciTech Connect

    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.

  4. - 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.

  5. Constraint on dark matter central density in the Eddington inspired Born-Infeld (EiBI) gravity with input from Weyl gravity

    NASA Astrophysics Data System (ADS)

    Potapov, Alexander A.; Izmailov, Ramil; Mikolaychuk, Olga; Mikolaychuk, Nikolay; Ghosh, Mithun; Nandi, Kamal K.

    2015-07-01

    Recently, Harko et al. (2014) derived an approximate metric of the galactic halo in the Eddington inspired Born-Infeld (EiBI) gravity. In this metric, we show that there is an upper limit ρ 0upper on the central density ρ 0 of dark matter such that stable circular orbits are possible only when the constraint ρ 0<= ρ 0upper is satisfied in each galactic sample. To quantify different ρ 0upper for different samples, we follow the novel approach of Edery & Paranjape (1998), where we use as input the geometric halo radius RWR from Weyl gravity and equate it with the dark matter radius RDM from EiBI gravity for the same halo boundary. This input then shows that the known fitted values of ρ 0 obey the constraint ρ 0<= ρ 0upperpropto (RWR)-2. Using the mass-to-light ratios giving α , we shall also evaluate ρ 0lower propto (α -1)MlumRWR-3 and the average dark matter density langle ρ rangle lower. Quantitatively, it turns out that the interval ρ 0lower <= ρ 0<= ρ 0upper verifies reasonably well against many dark matter dominated low surface brightness (LSB) galaxies for which values of ρ 0 are independently known. The interval holds also in the case of Milky Way galaxy. Qualitatively, the existence of a stability induced upper limit ρ 0upper is a remarkable prediction of the EiBI theory.

  6. Constraint on dark matter central density in the Eddington inspired Born-Infeld (EiBI) gravity with input from Weyl gravity

    SciTech Connect

    Potapov, Alexander A.; Mikolaychuk, Olga; Mikolaychuk, Nikolay; Nandi, Kamal K.; Izmailov, Ramil; Ghosh, Mithun E-mail: izmailov.ramil@gmail.com E-mail: mikov94@mail.ru E-mail: kamalnandi1952@yahoo.co.in

    2015-07-01

    Recently, Harko et al. (2014) derived an approximate metric of the galactic halo in the Eddington inspired Born-Infeld (EiBI) gravity. In this metric, we show that there is an upper limit ρ {sub 0}{sup upper} on the central density ρ {sub 0} of dark matter such that stable circular orbits are possible only when the constraint ρ {sub 0}≤ ρ {sub 0}{sup upper} is satisfied in each galactic sample. To quantify different ρ {sub 0}{sup upper} for different samples, we follow the novel approach of Edery and Paranjape (1998), where we use as input the geometric halo radius R{sub WR} from Weyl gravity and equate it with the dark matter radius R{sub DM} from EiBI gravity for the same halo boundary. This input then shows that the known fitted values of ρ {sub 0} obey the constraint ρ {sub 0}≤ ρ {sub 0}{sup upper}∝  (R{sub WR}){sup −2}. Using the mass-to-light ratios giving α , we shall also evaluate ρ {sub 0}{sup lower} ∝  (α −1)M{sub lum}R{sub WR}{sup −3} and the average dark matter density  ( ρ ) {sup lower}. Quantitatively, it turns out that the interval ρ {sub 0}{sup lower} ≤ ρ {sub 0}≤  ρ {sub 0}{sup upper} verifies reasonably well against many dark matter dominated low surface brightness (LSB) galaxies for which values of ρ {sub 0} are independently known. The interval holds also in the case of Milky Way galaxy. Qualitatively, the existence of a stability induced upper limit  ρ {sub 0}{sup upper} is a remarkable prediction of the EiBI theory.

  7. Born-Infeld extension of Lovelock brane gravity in the system of M0-branes and its application for the emergence of Pauli exclusion principle in BIonic superconductors

    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

  8. Thermodynamics of third-order Lovelock-AdS black holes in the presence of Born-Infeld type nonlinear electrodynamics

    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.

  9. Eddington's theory of gravity and its progeny.

    PubMed

    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.

  10. P-V criticality and geometrical thermodynamics of black holes with Born-Infeld type nonlinear electrodynamics

    NASA Astrophysics Data System (ADS)

    Hendi, S. H.; Panahiyan, S.; Eslam Panah, B.

    2016-10-01

    In this paper, we take into account the black-hole solutions of Einstein gravity in the presence of logarithmic and exponential forms of nonlinear electrodynamics. At first, we consider the cosmological constant as a dynamical pressure to study the phase transitions and analogy of the black holes with the Van der Waals liquid-gas system in the extended phase space. We make a comparison between linear and nonlinear electrodynamics and show that the lowest critical temperature belongs to Maxwell theory. Also, we make some arguments regarding how power of nonlinearity brings the system to Schwarzschild-like and Reissner-Nordström-like limitations. Next, we study the critical behavior of the system in the context of heat capacity. We show that critical behavior of system is similar to the one in phase diagrams of extended phase space. We also extend the study of phase transition points through geometrical thermodynamics (GTs). We introduce two new thermodynamical metrics for extended phase space and show that divergencies of thermodynamical Ricci scalar (TRS) of the new metrics coincide with phase transition points of the system. Then, we introduce a new method for obtaining critical pressure and horizon radius by considering denominator of the heat capacity.

  11. Eddington's theory of gravity and its progeny.

    PubMed

    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

  12. String theory in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Ambjørn, Jan; Makeenko, Yuri M.; Semenoff, Gordon W.; Szabo, Richard J.

    2003-02-01

    A review of various aspects of superstrings in background electromagnetic fields is presented. Topics covered include the Born-Infeld action, spectrum of open strings in background gauge fields, the Schwinger mechanism, finite-temperature formalism and Hagedorn behaviour in external fields, Debye screening, D-brane scattering, thermodynamics of D-branes, and noncommutative field and string theories on D-branes. The electric field instabilities are emphasized throughout and contrasted with the case of magnetic fields. A new derivation of the velocity-dependent potential between moving D-branes is presented, as is a new result for the velocity corrections to the one-loop thermal effective potential.

  13. Dark energy properties in DBI theory

    SciTech Connect

    Ahn, Changrim; Kim, Chanju; Linder, Eric V.

    2009-12-15

    The Dirac-Born-Infeld (DBI) action from string theory provides several new classes of dark energy behavior beyond quintessence due to its relativistic kinematics. We constrain parameters of natural potentials and brane tensions with cosmological observations as well as showing how to design these functions for a desired expansion history. We enlarge the attractor solutions, including new ways of obtaining cosmological constant behavior, to the case of generalized DBI theory with multiple branes. An interesting novel signature of DBI attractors is that the sound speed is driven to zero, unlike for quintessence where it is the speed of light.

  14. All bulk and boundary unitary cubic curvature theories in three dimensions

    SciTech Connect

    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.

  15. Massive Gravity theories and limits of ghost-free bigravity models

    NASA Astrophysics Data System (ADS)

    Paulos, Miguel F.; Tolley, Andrew J.

    2012-09-01

    We construct a class of theories which extend New Massive Gravity to higher orders in curvature in any dimension. The lagrangians arise as limits of a new class of bimetric theories of Lovelock gravity, which are unitary theories free from the Boulware-Deser ghost. These Lovelock bigravity models represent the most general non-chiral ghost-free theories of an interacting massless and massive spin-two field in any dimension. The scaling limit is taken in such a way that unitarity is explicitly broken, but the Boulware-Deser ghost remains absent. This automatically implies the existence of a holographic c-theorem for these theories. We also show that the Born-Infeld extension of New Massive Gravity falls into our class of models demonstrating that this theory is also free of the Boulware-Deser ghost. These results extend existing connections between New Massive Gravity, bigravity theories, Galileon theories and holographic c-theorems.

  16. Enhanced inflation in the Dirac-Born-Infeld framework

    SciTech Connect

    Chimento, Luis P.; Richarte, Martin G.; Lazkoz, Ruth

    2011-03-15

    We consider the Einstein equations within the Dirac-Born-Infield (DBI) scenario for a spatially flat Friedmann-Robertson-Walker (FRW) spacetime without a cosmological constant. We derive the inflationary scenario by applying the symmetry transformations which preserve the form of the Friedmann and conservation equations. These form invariance transformations generate a symmetry group parametrized by the Lorentz factor {gamma}. We explicitly obtain an inflationary scenario by the cooperative effect of adding energy density into the Friedmann equation. For the case of a constant Lorentz factor, and under the slow roll assumption, we find the transformation rules for the scalar and tensor power spectra of perturbations as well as their ratio under the action of the form invariance symmetry group. Within this case and due to its relevance for the inflationary paradigm, we find the general solution of the dynamical equations for a DBI field driven by an exponential potential and show a broad set of inflationary solutions. The general solution can be split into three subsets and all these behave asymptotically as a power-law solution at early and at late times.

  17. BTZ-like black holes in even dimensional Lovelock theories

    SciTech Connect

    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.

  18. Vacuum static compactified wormholes in eight-dimensional Lovelock theory

    SciTech Connect

    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.

  19. 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.

  20. DBI Galileon in the effective field theory of inflation: orthogonal non-Gaussianities and constraints from the Trispectrum

    SciTech Connect

    Renaux-Petel, Sébastien

    2013-08-01

    Very few explicit inflationary scenarios are known to generate a large bispectrum of orthogonal shape. Dirac-Born-Infeld Galileon inflation, in which an induced gravity term is added to the DBI action, is one such model. We formulate it in the language of the effective field theory of inflation by identifying the unitary gauge operators that govern the behavior of its cosmological fluctuations. We show how to recover rather easily from this its power spectrum and bispectrum, which we calculated previously using standard cosmological perturbation theory. We push our calculations up to the determination of the fourth-order action and of the trispectrum, in which shapes absent in k-inflation arise due to the presence of higher-order derivative operators. We finally discuss the combined constraints set on this model by current observational bounds on the bispectrum and trispectrum.

  1. 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.

  2. 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.

  3. Interacting giant gravitons from spin matrix theory

    NASA Astrophysics Data System (ADS)

    Harmark, Troels

    2016-09-01

    Using the non-Abelian Dirac-Born-Infeld action we find an effective matrix model that describes the dynamics of weakly interacting giant gravitons wrapped on three-spheres in the anti-de Sitter (AdS) part of AdS5×S5 at high energies with two angular momenta on the S5. In parallel we consider the limit of N =4 super Yang-Mills theory near a certain unitarity bound where it reduces to the quantum mechanical theory called S U (2 ) spin matrix theory. We show that the exact same matrix model that describes the giant gravitons on the string theory side also provides the effective description in the strong coupling and large energy limit of the spin matrix theory. Thus, we are able to match nonsupersymmetric dynamics of D-branes on AdS5×S5 to a finite-N regime in N =4 super Yang-Mills theory near a unitarity bound.

  4. Kinetic mixing in scalar-tensor theories of gravity

    NASA Astrophysics Data System (ADS)

    Bettoni, Dario; Zumalacárregui, Miguel

    2015-05-01

    Kinetic mixing between the metric and scalar degrees of freedom is an essential ingredient in contemporary scalar-tensor theories. This often makes it hard to understand their physical content, especially when derivative mixing is present, as is the case for Horndeski action. In this work we develop a method that allows us to write a Ricci-curvature-free scalar field equation, and we discuss some of the advantages of such a rephrasing in the study of stability issues in the presence of matter, the existence of an Einstein frame, and the generalization of the disformal screening mechanism. For quartic Horndeski theories, such a procedure leaves, in general, a residual coupling to the curvature, given by the Weyl tensor. This gives rise to a binary classification of scalar-tensor theories into stirred theories, in which the curvature can be substituted, and shaken theories, in which a residual coupling to the curvature remains. Quite remarkably, we have found that generalized Dirac-Born-Infeld Galileons belong to the first class. Finally, we discuss kinetic mixing in quintic theories, in which nonlinear mixing terms appear, and in the recently proposed theories beyond Horndeski that display a novel form of kinetic mixing, in which the field equation is sourced by derivatives of the energy-momentum tensor.

  5. 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.

  6. 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.

  7. Embedding DBI inflation in scalar-tensor theory

    SciTech Connect

    Bruck, Carsten van de; Weller, Joel M.; Mota, David F. E-mail: d.f.mota@astro.uio.no

    2011-03-01

    The Dirac-Born-Infeld (DBI) action has been widely studied as an interesting example of a model of k-inflation in which the sound speed of the cosmological perturbations differs from unity. In this article we consider a scalar-tensor theory in which the matter component is a field with a DBI action. Transforming to the Einstein frame, we explore the effect of the resulting coupling on the background dynamics of the fields and the first-order perturbations. We find that the coupling forces the scalar field into the minimum of its effective potential. While the additional scalar field contributes significantly to the energy density during inflation, the dynamics are determined by the DBI field, which has the interesting effect of increasing the number of efolds of inflation and decreasing the boost factor of the DBI field. Focusing on this case, we show, with the benefit of numerical examples, that the power spectrum of the primordial perturbations is determined by the behaviour of the perturbations of the modified DBI field.

  8. Testing universal relations of neutron stars with a nonlinear matter-gravity coupling theory

    SciTech Connect

    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.

  9. 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.

  10. Charged anti-de Sitter scalar-tensor black holes and their thermodynamic phase structure

    SciTech Connect

    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.

  11. Non-perturbative aspects of particle acceleration in non-linear electrodynamics

    SciTech Connect

    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.

  12. 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.

  13. 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.

  14. Thermodynamics of Scalar-tensor AdS Black Holes Coupled to Nonlinear Electrodynamics

    SciTech Connect

    Doneva, D.; Yazadjiev, S.; Kokkotas, K.; Stefanov, I.; Todorov, M.

    2010-11-25

    We construct new numerical solutions describing charged anti-de Sitter black holes coupled to nonlinear Born-Infeld electrodynamics within a certain class of scalar-tensor theories and we study their thermodynamic phase structure. It is shown that for certain charge intervals phase transitions of zeroth and first order exist.

  15. Stability of charged thin shells

    SciTech Connect

    Eiroa, Ernesto F.; Simeone, Claudio

    2011-05-15

    In this article we study the mechanical stability of spherically symmetric thin shells with charge, in Einstein-Maxwell and Einstein-Born-Infeld theories. We analyze linearized perturbations preserving the symmetry, for shells around vacuum and shells surrounding noncharged black holes.

  16. Some special features of a rotating-moving Dp-brane

    NASA Astrophysics Data System (ADS)

    Safarzadeh-Maleki, Farzin

    2016-07-01

    Using the boundary string field theory (BSFT) techniques we study the boundary state and partition function for a dynamical (rotating-moving) Dp-brane coupled to the electromagnetic and tachyonic background fields in superstring theory. By making use of the created partition function, the super BSFT action with a tachyonic field and Dirac-Born-Infeld-type action will be constructed. By analyzing the obtained action interesting features will be revealed.

  17. 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.

  18. Relations between canonical and non-canonical inflation

    SciTech Connect

    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.

  19. 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.

  20. Massive gravity coupled to Galileons is ghost-free.

    PubMed

    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.

  1. Some remarks on unilateral matrix equations

    SciTech Connect

    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.

  2. 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.

  3. 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.

  4. 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.

  5. Massive gravity coupled to Galileons is ghost-free.

    PubMed

    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

  6. Distinguishing k-defects from their canonical twins

    SciTech Connect

    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.

  7. Multiple D/p-branes in weak background fields

    NASA Astrophysics Data System (ADS)

    Taylor, Washington, IV; Van Raamsdonk, Mark

    2000-05-01

    We find the terms in the non-abelian world-volume action of a system of many Dp-branes which describe the leading coupling to all type II supergravity background fields. These results are found by T-dualizing earlier results for D0-branes, which in turn were determined from calculations of the M(atrix) theory description of the supercurrent of 11D supergravity. Our results are compatible with earlier results on the supersymmetric Born-Infeld action for a single D-brane in a general background and with Tseytlin's symmetrized trace proposal for extending the abelian Born-Infeld action to a non-abelian theory. In the case p=3, the operators we find on the D-brane world-volume are closely related to those which couple to supergravity fields in the AdS 5× S5 IIB supergravity background. This gives an explicit construction, including normalization, of some of the operators used in the celebrated AdS/CFT correspondence for 3-branes. We also discuss the S-duality of the action in the case p=3, finding that the S-duality of the action determines how certain operators in the N=4 4D SYM theory transform under S-duality. These S-duality results give some new insight into the puzzle of the transverse 5-brane in M(atrix) theory.

  8. String Theory and Gauge Theories

    SciTech Connect

    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.

  9. Geographical Theories.

    ERIC Educational Resources Information Center

    Golledge, Reginald G.

    1996-01-01

    Discusses the origin of theories in geography and particularly the development of location theories. Considers the influence of economic theory on agricultural land use, industrial location, and geographic location theories. Explores a set of interrelated activities that show how the marketing process illustrates process theory. (MJP)

  10. Spinflation

    SciTech Connect

    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.

  11. 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.

  12. Packaging Theory.

    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…

  13. Grounded theory.

    PubMed

    Harris, Tina

    2015-04-29

    Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it. It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read.

  14. Probability Theory

    NASA Astrophysics Data System (ADS)

    Jaynes, E. T.; Bretthorst, G. Larry

    2003-04-01

    Foreword; Preface; Part I. Principles and Elementary Applications: 1. Plausible reasoning; 2. The quantitative rules; 3. Elementary sampling theory; 4. Elementary hypothesis testing; 5. Queer uses for probability theory; 6. Elementary parameter estimation; 7. The central, Gaussian or normal distribution; 8. Sufficiency, ancillarity, and all that; 9. Repetitive experiments, probability and frequency; 10. Physics of 'random experiments'; Part II. Advanced Applications: 11. Discrete prior probabilities, the entropy principle; 12. Ignorance priors and transformation groups; 13. Decision theory: historical background; 14. Simple applications of decision theory; 15. Paradoxes of probability theory; 16. Orthodox methods: historical background; 17. Principles and pathology of orthodox statistics; 18. The Ap distribution and rule of succession; 19. Physical measurements; 20. Model comparison; 21. Outliers and robustness; 22. Introduction to communication theory; References; Appendix A. Other approaches to probability theory; Appendix B. Mathematical formalities and style; Appendix C. Convolutions and cumulants.

  15. Interacting spin-2 fields in the Stückelberg picture

    SciTech Connect

    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.

  16. New massive gravity and AdS(4) counterterms.

    PubMed

    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

  17. New Massive Gravity and AdS{sub 4} Counterterms

    SciTech Connect

    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.

  18. Graph Theory

    SciTech Connect

    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.

  19. Game theory.

    PubMed

    Dufwenberg, Martin

    2011-03-01

    Game theory is a toolkit for examining situations where decision makers influence each other. I discuss the nature of game-theoretic analysis, the history of game theory, why game theory is useful for understanding human psychology, and why game theory has played a key role in the recent explosion of interest in the field of behavioral economics. WIREs Cogni Sci 2011 2 167-173 DOI: 10.1002/wcs.119 For further resources related to this article, please visit the WIREs website.

  20. Confabulation Theory

    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.

  1. Tachyon effective dynamics and de Sitter vacua

    SciTech Connect

    Carneiro da Cunha, Bruno

    2004-09-15

    We show that the Dirac-Born-Infeld (DBI) action for the singlet sector of the tachyon in two-dimensional string theory has a SL(2,R) symmetry, a real-time counterpart of the ground ring. The action can be rewritten as that of point particles moving in a de Sitter space, whose coordinates are given by the value of the eigenvalue and time. The symmetry then manifests as the isometry group of de Sitter space in two dimensions. We use this fact to write the collective field theory for a large number of branes, which has a natural interpretation as a fermion field in this de Sitter space. After spending some time building geometrical insight on facts about the condensation process, the state corresponding to a sD-brane is identified and standard results in quantum field theory in curved spacetime are used to compute the backreaction of the thermal background.

  2. 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.

  3. Phantom energy mediates a long-range repulsive force.

    PubMed

    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.

  4. Holographic Quantum Liquid

    SciTech Connect

    Karch, A.; Son, D. T.; Starinets, A. O.

    2009-02-06

    Quantum liquids are characterized by the distinctive properties such as the low-temperature behavior of heat capacity and the spectrum of low-energy quasiparticle excitations. In particular, at low temperature, Fermi liquids exhibit the zero sound, predicted by Landau in 1957 and subsequently observed in liquid He-3. In this Letter, we ask whether such characteristic behavior is present in theories with a holographically dual description. We consider a class of gauge theories with fundamental matter fields whose holographic dual in the appropriate limit is given in terms of the Dirac-Born-Infeld action in anti-de Sitter space. We find that these systems also exhibit a sound mode at zero temperature despite having a non-Fermi-liquid behavior of the specific heat. These properties suggest that holography identifies a new type of quantum liquid which potentially could be experimentally realized in strongly correlated systems.

  5. Matrix σ-MODELS for Multi D-Brane Dynamics

    NASA Astrophysics Data System (ADS)

    Lizzi, Fedele; Mavromatos, Nick E.; Szabo, Richard J.

    We describe a dynamical worldsheet origin for the Lagrangian describing the low-energy dynamics of a system of parallel D-branes. We show how matrix-valued collective coordinate fields for the D-branes naturally arise as couplings of a worldsheet σ-model, and that the quantum dynamics require that these couplings be mutually noncommutative. We show that the low-energy effective action for the σ-model couplings describes the propagation of an open string in the background of the multiple D-brane configuration, in which all string interactions between the constituent branes are integrated out and the genus expansion is taken into account, with a matrix-valued coupling. The effective field theory is governed by the non-Abelian Born-Infeld target space action which leads to the standard one for D-brane field theory.

  6. 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.

  7. Optimal bispectrum constraints on single-field models of inflation

    SciTech Connect

    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.

  8. Galileons coupled to massive gravity: general analysis and cosmological solutions

    SciTech Connect

    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.

  9. 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.

  10. Effective theories of universal theories

    DOE PAGESBeta

    Wells, James D.; Zhang, Zhengkang

    2016-01-20

    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. The oblique parameters should not be associated with Wilson coefficients in a particular operator basis in the effective field theory (EFT) framework, unless restrictions have been imposed on the EFT so that it describes universal theories. Here, 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 16more » 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 h3, hff, hV V vertices, 3 parameters for hV V vertices absent in the Standard Model, and 1 four-fermion coupling of order yf2. Furthermore, 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.« less

  11. Communication Theory.

    ERIC Educational Resources Information Center

    Penland, Patrick R.

    Three papers are presented which delineate the foundation of theory and principles which underlie the research and instructional approach to communications at the Graduate School of Library and Information Science, University of Pittsburgh. Cybernetic principles provide the integration, and validation is based in part on a situation-producing…

  12. Electroweak Theory

    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

  13. Leadership Theories.

    ERIC Educational Resources Information Center

    Sferra, Bobbie A.; Paddock, Susan C.

    This booklet describes various theoretical aspects of leadership, including the proper exercise of authority, effective delegation, goal setting, exercise of control, assignment of responsibility, performance evaluation, and group process facilitation. It begins by describing the evolution of general theories of leadership from historic concepts…

  14. Control Theory.

    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)

  15. 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…

  16. Bimetric structure formation: Non-Gaussian predictions

    SciTech Connect

    Magueijo, Joao; Noller, Johannes; Piazza, Federico

    2010-08-15

    The minimal bimetric theory employing a disformal transformation between matter and gravity metrics is known to produce exactly scale-invariant fluctuations. It has a purely equilateral non-Gaussian signal, with an amplitude smaller than that of Dirac Born Infeld inflation (with opposite sign) but larger than standard inflation. We consider nonminimal bimetric models, where the coupling B appearing in the disformal transformation g-circumflex{sub {mu}{nu}}=g{sub {mu}{nu}}-B{partial_derivative}{sub {mu}{phi}{partial_derivative}{nu}{phi}} can run with {phi}. For power-law B({phi}) these models predict tilted spectra. For each value of the spectral index, a distinctive distortion to the equilateral property can be found. The constraint between this distortion and the spectral index can be seen as a 'consistency relation' for nonminimal bimetric models.

  17. Bimetric structure formation: Non-Gaussian predictions

    NASA Astrophysics Data System (ADS)

    Magueijo, João; Noller, Johannes; Piazza, Federico

    2010-08-01

    The minimal bimetric theory employing a disformal transformation between matter and gravity metrics is known to produce exactly scale-invariant fluctuations. It has a purely equilateral non-Gaussian signal, with an amplitude smaller than that of Dirac Born Infeld inflation (with opposite sign) but larger than standard inflation. We consider nonminimal bimetric models, where the coupling B appearing in the disformal transformation g^μν=gμν-B∂μϕ∂νϕ can run with ϕ. For power-law B(ϕ) these models predict tilted spectra. For each value of the spectral index, a distinctive distortion to the equilateral property can be found. The constraint between this distortion and the spectral index can be seen as a “consistency relation” for nonminimal bimetric models.

  18. D-flation

    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.

  19. D-flation

    SciTech Connect

    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.

  20. Emergent cosmological constant from colliding electromagnetic waves

    SciTech Connect

    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.

  1. Scale invariance and a gravitational model with non-eternal inflation

    SciTech Connect

    Herdeiro, Carlos; Hirano, Shinji E-mail: hirano@eken.phys.nagoya-u.ac.jp

    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.

  2. Quantum theory of gravity

    SciTech Connect

    Christensen, S.M.

    1984-01-01

    The book of essay entitled Quantum Theory of Gravity, edited by Steven M. Christensen is reviewed. The book contains over thirty papers dealing with the subject of the unification of quantum field theory and general relativity theory. Contributions include discussions of non-Abelian gauge theories, supersymmetry, issues in renormalization and quantization and matters related to the interpretation of theories.

  3. Generating Curriculum Theory Through Grounded Theory Research.

    ERIC Educational Resources Information Center

    Gehrke, Nathalie J.; Parker, Walter C.

    The purpose of this paper is threefold: to describe grounded theory research strategies, to present a summary of several studies in education that have followed this approach, and to explore the potential uses of the grounded theory techniques in curriculum theory generation. The paper is arranged into six parts. In the first and second parts of…

  4. String Theory and M-Theory

    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

  5. Grounded theory, feminist theory, critical theory: toward theoretical triangulation.

    PubMed

    Kushner, Kaysi Eastlick; Morrow, Raymond

    2003-01-01

    Nursing and social science scholars have examined the compatibility between feminist and grounded theory traditions in scientific knowledge generation, concluding that they are complementary, yet not without certain tensions. This line of inquiry is extended to propose a critical feminist grounded theory methodology. The construction of symbolic interactionist, feminist, and critical feminist variants of grounded theory methodology is examined in terms of the presuppositions of each tradition and their interplay as a process of theoretical triangulation.

  6. 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.

  7. Theories and Modes

    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…

  8. 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.

  9. 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…

  10. 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…

  11. 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)

  12. Disengagement theory revisited.

    PubMed

    Markson, E W

    1975-01-01

    Cumming and Henry erected the basic frame for a socio-cultural theory of normal aging in their 1961 book, Growing Old. The basic postulates of this theory are reviewed, and the overall structure of the theory briefly examined. Critical data necessary either to accept or reject disengagement theory are not yet available, although useful information has been gathered since the theory first appeared. Part of the difficulty in amassing "proof" or "disproof" is inherent in the intricate and complex nature of the aging process itself. This orienting paper introduced a set of contributtions by other commentators on disengagement theory.

  13. Elementary particle theory

    SciTech Connect

    Marciano, W.J.

    1984-12-01

    The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references. (WHK)

  14. Dissipative Field Theory

    SciTech Connect

    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.

  15. Covariant Noncommutative Field Theory

    SciTech Connect

    Estrada-Jimenez, S.; Garcia-Compean, H.; Obregon, O.; Ramirez, C.

    2008-07-02

    The covariant approach to noncommutative field and gauge theories is revisited. In the process the formalism is applied to field theories invariant under diffeomorphisms. Local differentiable forms are defined in this context. The lagrangian and hamiltonian formalism is consistently introduced.

  16. 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.…

  17. Measurement Decision Theory.

    ERIC Educational Resources Information Center

    Rudner, Lawrence M.

    This paper describes and evaluates the use of decision theory as a tool for classifying examinees based on their item response patterns. Decision theory, developed by A. Wald (1947) and now widely used in engineering, agriculture, and computing, provides a simple model for the analysis of categorical data. Measurement decision theory requires only…

  18. Activity Theory and Ontology

    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…

  19. 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…

  20. Constructor theory of probability

    PubMed Central

    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.

  1. Constructor theory of probability

    PubMed Central

    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

  2. Frankl's Theory and Therapy.

    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…

  3. Whither Social Theory?

    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…

  4. Quantum Electrodynamics: Theory

    ScienceCinema

    Lincoln, Don

    2016-07-12

    The Standard Model of particle physics is composed of several theories that are added together. The most precise component theory is the theory of quantum electrodynamics or QED. In this video, Fermilab’s Dr. Don Lincoln explains how theoretical QED calculations can be done. This video links to other videos, giving the viewer a deep understanding of the process.

  5. Constructor theory of probability

    NASA Astrophysics Data System (ADS)

    Marletto, Chiara

    2016-08-01

    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.

  6. 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)

  7. Family systems theory, attachment theory, and culture.

    PubMed

    Rothbaum, Fred; Rosen, Karen; Ujiie, Tatsuo; Uchida, Nobuko

    2002-01-01

    Family systems theory and attachment theory have important similarities and complementarities. Here we consider two areas in which the theories converge: (a) in family system theorists' description of an overly close, or "enmeshed," mother-child dyad, which attachment theorists conceptualize as the interaction of children's ambivalent attachment and mothers' preoccupied attachment; (b) in family system theorists' description of the "pursuer-distance cycle" of marital conflict, which attachment theorists conceptualize as the interaction of preoccupied and dismissive partners. We briefly review family systems theory evidence, and more extensively review attachment theory evidence, pertaining to these points of convergence. We also review cross-cultural research, which leads us to conclude that the dynamics described in both theories reflect, in part, Western ways of thinking and Western patterns of relatedness. Evidence from Japan suggests that extremely close ties between mother and child are perceived as adaptive, and are more common, and that children experience less adverse effects from such relationships than do children in the West. Moreover, in Japan there is less emphasis on the importance of the exclusive spousal relationship, and less need for the mother and father to find time alone to rekindle romantic, intimate feelings and to resolve conflicts by openly communicating their differences. Thus, the "maladaptive" pattern frequently cited by Western theorists of an extremely close mother-child relationship, an unromantic, conflictual marriage characterized by little verbal communication and a peripheral, distant father, may function very differently in other cultures. While we believe that both theories will be greatly enriched by their integration, we caution against the application of either theory outside the cultures in which they were developed.

  8. Theory Interpretations in PVS

    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.

  9. Rate theories for biologists

    PubMed Central

    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

  10. [Introduction to grounded theory].

    PubMed

    Wang, Shou-Yu; Windsor, Carol; Yates, Patsy

    2012-02-01

    Grounded theory, first developed by Glaser and Strauss in the 1960s, was introduced into nursing education as a distinct research methodology in the 1970s. The theory is grounded in a critique of the dominant contemporary approach to social inquiry, which imposed "enduring" theoretical propositions onto study data. Rather than starting from a set theoretical framework, grounded theory relies on researchers distinguishing meaningful constructs from generated data and then identifying an appropriate theory. Grounded theory is thus particularly useful in investigating complex issues and behaviours not previously addressed and concepts and relationships in particular populations or places that are still undeveloped or weakly connected. Grounded theory data analysis processes include open, axial and selective coding levels. The purpose of this article was to explore the grounded theory research process and provide an initial understanding of this methodology.

  11. 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.

  12. Children's theories of motivation.

    PubMed

    Gurland, Suzanne T; Glowacky, Victoria C

    2011-09-01

    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 the long term for appealing activities. Individual difference analyses revealed that some children held operant theories of motivation, in which rewards were central, and others held hybrid theories, in which rewards were key, but some allowance was made for interest to be self-sustaining in the absence of inducements. Children's theories predicted their academic self-regulation. Their theories are discussed relative to an expert theory of motivation.

  13. Galileo's tidal theory.

    PubMed

    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

  14. Galileo's tidal theory.

    PubMed

    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.

  15. Domains and Naive Theories

    PubMed Central

    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

  16. Children's theories of motivation.

    PubMed

    Gurland, Suzanne T; Glowacky, Victoria C

    2011-09-01

    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 the long term for appealing activities. Individual difference analyses revealed that some children held operant theories of motivation, in which rewards were central, and others held hybrid theories, in which rewards were key, but some allowance was made for interest to be self-sustaining in the absence of inducements. Children's theories predicted their academic self-regulation. Their theories are discussed relative to an expert theory of motivation. PMID:21513944

  17. Riding on irrelevant operators

    SciTech Connect

    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.

  18. Automated Lattice Perturbation Theory

    SciTech Connect

    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.

  19. Theory Modeling and Simulation

    SciTech Connect

    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.

  20. Ostwald ripening theory

    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.

  1. The Big Bang Theory

    ScienceCinema

    Lincoln, Don

    2016-07-12

    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.

  2. The Big Bang Theory

    SciTech Connect

    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.

  3. 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.

  4. Why Do We Have Theories?

    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…

  5. [United theory of aging].

    PubMed

    Trubitsyn, A G

    2012-01-01

    In attempts to develop a means of life prolongation the humankind has created more than three hundred theories of the aging; each of them offers the original cause of aging. However, none of them has given practical result by now. The majority of the theories have now only historical interest. There are several different theories that are mainly under consideration currently. They are based on reliable, proven evidence: the free radical theory, the protein error theory, the replicative senescence theory, the theory of reparation weakening, the immunological theory, several versions of neuroendocrinal theories, and programmed aging theory. The theory presented here is based on conception that the life as the phenomenon represents many of the interconnected physical and chemical processes propelled by energy of the mitochondrial bioenergetical machine. Gradual degradation of all vital processes is caused by the programmed decrease in level of bioenergetics. This theory unites all existing theories of aging constructed on authentic facts: it is shown, that such fundamental phenomena accompanying aging process as the increase in level of reactive oxygen species (ROS), the decrease in the general level of protein synthesis, the limitation of cellular dividing (Haiflick limit), decrease in efficiency of reparation mechanisms are caused by bioenergetics attenuation. Each of these phenomena in turn generates a number of harmful secondary processes. Any of the theories bases on one of these destructive phenomena or their combination. Hence, each of them describes one of sides of process of the aging initially caused by programmed decrease of level of bioenergetics. This united theory gives the chance to understand the nature of aging clock and explains a phenomenon of increase in longevity at the condition of food restriction. Failures of attempts to develop means from aging are explained by that the manipulations with the separate secondary phenomena of attenuation of

  6. Theory of thermoelasticity

    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.

  7. Education without Theory

    ERIC Educational Resources Information Center

    Carr, Wilfred

    2006-01-01

    This paper proceeds through four stages. First, it provides an account of the origins and evolution of the concept of educational theory. Second, it uses this historical narrative to show how what we now call "educational theory" is deeply rooted in the foundationalist discourse of late nineteenth and early twentieth century modernity. Third, it…

  8. Put Theory into Practice

    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.…

  9. 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.

  10. Evolution: Theory or Dogma?

    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)

  11. History, Theory, and Education

    ERIC Educational Resources Information Center

    Rury, John L.

    2011-01-01

    In this article, the author discusses the question of theory as it may pertain to the history of education, with particular attention to the United States. Historians, like everyone else, have little choice regarding the use of theory; to one extent or another they must. The question is how much and to what end. The author aims to consider the…

  12. Reimagining Critical Theory

    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…

  13. 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…

  14. 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…

  15. Greek Atomic Theory.

    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)

  16. The Learning Theory Jungle

    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…

  17. 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…

  18. Game Theory .net.

    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…

  19. Theories of Play.

    ERIC Educational Resources Information Center

    Peller, Lili E.

    1996-01-01

    Discusses several theories of play advanced before the development of psychoanalysis, including the theories of surplus energy, recreation, and practice. Examines the psychoanalytical view advanced by Freud and others, which focuses on the emotional release of play and its role in discovery and learning. (MDM)

  20. 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…

  1. Student Development as Theory.

    ERIC Educational Resources Information Center

    Rogers, Russell R.

    Student development theory has been adopted as the guiding theoretical framework of the student affairs profession. Unfortunately this adoption has largely occurred without a critical analysis of the concept of student development as a gestalt. A case can be made that for the most part the theories of student development are logically coherent in…

  2. Elementary Particle Theory

    SciTech Connect

    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.

  3. Test Theory Reconceived.

    ERIC Educational Resources Information Center

    Mislevy, Robert J.

    Educational test theory consists of statistical and methodological tools to support inferences about examinees' knowledge, skills, and accomplishments. The evolution of test theory has been shaped by the nature of users' inferences which, until recently, have been framed almost exclusively in terms of trait and behavioral psychology. Progress in…

  4. Progress in string theory

    NASA Astrophysics Data System (ADS)

    Maldacena, Juan Martín

    D-Branes on Calabi-Yau manifolds / Paul S. Aspinwall -- Lectures on AdS/CFT / Juan M. Maldacena -- Tachyon dynamics in open string theory / Ashoke Sen -- TASI/PITP/ISS lectures on moduli and microphysics / Eva Silverstein -- The duality cascade / Matthew J. Strassler -- Perturbative computations in string field theory / Washington Taylor -- Student seminars -- Student participants -- Lecturers, directors, and local organizing committee.

  5. What Is Integral Theory?

    ERIC Educational Resources Information Center

    Marquis, Andre

    2007-01-01

    Integral theory is a way of knowing that helps foster the recognition that disparate aspects of reality--such as biological constitution, cultural worldviews, felt-sense of selfhood, and social systems--are all critically important to any knowledge quest. Integral theory provides an "all quadrants, all levels" (K. Wilber, 2006, p. 26)…

  6. A theory of knowledge

    NASA Astrophysics Data System (ADS)

    Pachner, J.

    1984-11-01

    In order to make reliable predictions in any region of human activity, it is necessary to distinguish clearly what is based on experience and what is a construction of intellect. The theory of knowledge developed in the present paper is an attempt to devise a set of axioms that demarcate experience, as the only source of our knowledge of the external world, from the ideas, scientific models, and theories by means of which the scientific predictions are made. After a discussion of the causality in relation to the laws of nature, the axioms of the expounded theory are formulated in the formalism of set theory. The theory is then applied to some problems in physics to demonstrate its usefulness.

  7. Theory and speciation.

    PubMed

    Turelli, M; Barton, N H.; Coyne, J A.

    2001-07-01

    The study of speciation has become one of the most active areas of evolutionary biology, and substantial progress has been made in documenting and understanding phenomena ranging from sympatric speciation and reinforcement to the evolutionary genetics of postzygotic isolation. This progress has been driven largely by empirical results, and most useful theoretical work has concentrated on making sense of empirical patterns. Given the complexity of speciation, mathematical theory is subordinate to verbal theory and generalizations about data. Nevertheless, mathematical theory can provide a useful classification of verbal theories; can help determine the biological plausibility of verbal theories; can determine whether alternative mechanisms of speciation are consistent with empirical patterns; and can occasionally provide predictions that go beyond empirical generalizations. We discuss recent examples of progress in each of these areas.

  8. Algebraic Mean Field Theory

    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.

  9. Evolutionary game theory

    NASA Astrophysics Data System (ADS)

    Smith, John Maynard

    1986-10-01

    It is often the case that the best thing for an animal or plant to do depends on what other members of the population are doing. In more technical language, the fitnesses of different phenotypes are frequency-dependent. Evolutionary game theory has been developed to analyse such cases. In this paper I aim to do three things. First, I describe the concepts of evolutionary game theory in the context of a simple game, the Hawk-Dove game, and compare them with the concepts of classical game theory originating with Von Neumann and Morgenstern (1953) [1]. Second, I list some of the applications of the theory. Finally, I suggest how the theory can tell us something about the evolution of learning.

  10. Z-theory: chasing m/f theory

    NASA Astrophysics Data System (ADS)

    Nekrasov, Nikita

    2005-03-01

    We present the evidence for the existence of the topological string analogue of M-theory, which we call Z-theory. The corners of Z-theory moduli space correspond to the Donaldson-Thomas theory, Kodaira-Spencer theory, Gromov-Witten theory, and Donaldson-Witten theory. We discuss the relations of Z-theory with Hitchin's gravities in six and seven dimensions, and make our own proposal, involving spinor generalization of Chern-Simons theory of three-forms. To cite this article: N. Nekrasov, C. R. Physique 6 (2005).

  11. Quantum Theory and Beyond

    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

  12. 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.

  13. Introduction to string theory and conformal field theory

    SciTech Connect

    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.

  14. Theory X and Theory Y in the Organizational Structure.

    ERIC Educational Resources Information Center

    Barry, Thomas J.

    This document defines contrasting assumptions about the labor force--theory X and theory Y--and shows how they apply to the pyramid organizational structure, examines the assumptions of the two theories, and finally, based on a survey and individual interviews, proposes a merger of theories X and Y to produce theory Z. Organizational structures…

  15. String theory as a higher spin theory

    NASA Astrophysics Data System (ADS)

    Gaberdiel, Matthias R.; Gopakumar, Rajesh

    2016-09-01

    The symmetries of string theory on {AdS}_3× {S}^3× T^4 at the dual of the symmetric product orbifold point are described by a so-called Higher Spin Square (HSS). We show that the massive string spectrum in this background organises itself in terms of representations of this HSS, just as the matter in a conventional higher spin theory does so in terms of representations of the higher spin algebra. In particular, the entire untwisted sector of the orbifold can be viewed as the Fock space built out of the multiparticle states of a single representation of the HSS, the so-called `minimal' representation. The states in the twisted sector can be described in terms of tensor products of a novel family of representations that are somewhat larger than the minimal one.

  16. Set theory and physics

    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.

  17. Set theory and physics

    SciTech Connect

    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.

  18. Splines and control theory

    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.

  19. Neurological theory of hypertension.

    PubMed

    Eggers, A E

    2003-06-01

    Review of the older literature on the relationship between migraine and hypertension, written in the era before either condition could be treated, discloses a high rate of co-morbidity. A neurological theory of essential hypertension is proposed in which the two diseases are brought together into one entity. It is hypothesized that abnormally functioning serotonergic pacemaker cells in the dorsal raphe nucleus, as part of a chronic stress response, inappropriately activate and inhibit parts of the central and autonomic nervous systems, so as to cause the two conditions. This theory builds on a previously published neural theory of migraine.

  20. 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…

  1. Nonstandard Methods in Lie Theory

    ERIC Educational Resources Information Center

    Goldbring, Isaac Martin

    2009-01-01

    In this thesis, we apply model theory to Lie theory and geometric group theory. These applications of model theory come via nonstandard analysis. In Lie theory, we use nonstandard methods to prove two results. First, we give a positive solution to the local form of Hilbert's Fifth Problem, which asks whether every locally euclidean local…

  2. Drawing Out Theory: Art and the Teaching of Political Theory.

    ERIC Educational Resources Information Center

    Miller, Char R.

    2000-01-01

    Discusses how to use art in introductory political theory courses. Provides examples of incorporating art to teach political theory, such as examining Machiavelli's "The Prince" and Michelangelo's "David" to understand Florentine (Florence, Italy) political theory. (CMK)

  3. Why We "Knead" Theory

    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.

  4. 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.

  5. Lectures on Dispersion Theory

    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.)

  6. Classical Aerodynamic Theory

    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.

  7. Wormholes in string theory

    SciTech Connect

    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.

  8. Little M-theory

    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.

  9. Leonardo's Tree Theory.

    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)

  10. Compatible quantum theory.

    PubMed

    Friedberg, R; Hohenberg, P C

    2014-09-01

    Formulations of quantum mechanics (QM) can be characterized as realistic, operationalist, or a combination of the two. In this paper a realistic theory is defined as describing a closed system entirely by means of entities and concepts pertaining to the system. An operationalist theory, on the other hand, requires in addition entities external to the system. A realistic formulation comprises an ontology, the set of (mathematical) entities that describe the system, and assertions, the set of correct statements (predictions) the theory makes about the objects in the ontology. Classical mechanics is the prime example of a realistic physical theory. A straightforward generalization of classical mechanics to QM is hampered by the inconsistency of quantum properties with classical logic, a circumstance that was noted many years ago by Birkhoff and von Neumann. The present realistic formulation of the histories approach originally introduced by Griffiths, which we call 'compatible quantum theory (CQT)', consists of a 'microscopic' part (MIQM), which applies to a closed quantum system of any size, and a 'macroscopic' part (MAQM), which requires the participation of a large (ideally, an infinite) system. The first (MIQM) can be fully formulated based solely on the assumption of a Hilbert space ontology and the noncontextuality of probability values, relying in an essential way on Gleason's theorem and on an application to dynamics due in large part to Nistico. Thus, the present formulation, in contrast to earlier ones, derives the Born probability formulas and the consistency (decoherence) conditions for frameworks. The microscopic theory does not, however, possess a unique corpus of assertions, but rather a multiplicity of contextual truths ('c-truths'), each one associated with a different framework. This circumstance leads us to consider the microscopic theory to be physically indeterminate and therefore incomplete, though logically coherent. The completion of the theory

  11. Theory of lifting surfaces

    NASA Technical Reports Server (NTRS)

    Prandtl , L

    1920-01-01

    The general basis of the theory of lifting surfaces is discussed. The problem of the flow of a fluid about a lifting surface of infinite span is examined in terms of the existence of vortexes in the current. A general theory of permanent flow is discussed. Formulas for determining the influence of aspect ratio that may be applied to all wings, whatever their plane form, are given.

  12. Instantons in string theory

    SciTech Connect

    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.

  13. Hell of a theory.

    PubMed

    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

  14. Kinetic Theory of Gases

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The theory, developed in the nineteenth century, notably by Rudolf Clausius (1822-88) and James Clerk Maxwell (1831-79), that the properties of a gas (temperature, pressure, etc) could be described in terms of the motions (and kinetic energy) of the molecules comprising the gases. The theory has wide implications in astrophysics. In particular, the perfect gas law, which relates the pressure, vol...

  15. 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.

  16. Leadership and attachment theory.

    PubMed

    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.

  17. Leadership styles and theories.

    PubMed

    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

  18. Hell of a theory.

    PubMed

    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.

  19. Leadership styles and theories.

    PubMed

    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.

  20. On complicity theory.

    PubMed

    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.

  1. Constructor theory of life.

    PubMed

    Marletto, Chiara

    2015-03-01

    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.

  2. Constructor theory of life

    PubMed Central

    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

  3. 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.

  4. Parity in knot theory

    SciTech Connect

    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.

  5. Topics in string theory

    SciTech Connect

    Liu, J.

    1988-01-01

    The author discusses several aspects of string theory. First, he calculates the vacuum amplitude of un-oriented open and closed string theory using Polyakov formalism. He argues that the volume of the Mobius Group should be renormalized, and solve a minor paradox. Second, he gives an example of a membrane whose effective action is the generalization of Green-Schwarz covariant superstring action. As a by-product, he shows that is also provides an example of partially broken global supersymmetry. The rest of the dissertation is devoted to the study of string field theory in terms of the renormalization group approach. He emphasizes the pivotal role of the conformal invariance in string theory. He proposes the generalized Wilsonian conformal renormalization group equation of 2-dimensional quantum field theory as the field equation for string field theory following Banks and Martinec. He then finds general solutions to the linearized equation on the flat back-ground and its correspondence to all the physical vertex operators. He also makes detailed study of massless modes and offer some remarks about how gauge invariance arise in this approach. Finally, he solves the full nonlinear equation iteratively in terms of the solutions to the linearized equation and extract the Virasoro-Shapiro amplitudes from them.

  6. New insights on the matter-gravity coupling paradigm.

    PubMed

    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.

  7. Scalar speed limits and cosmology: Acceleration from D-cceleration

    SciTech Connect

    Silverstein, Eva

    2004-11-15

    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 Poincare 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.

  8. New insights on the matter-gravity coupling paradigm.

    PubMed

    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

  9. 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)

  10. 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

  11. 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.

  12. 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.

  13. Finite quantum gauge theories

    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).

  14. Physics as Information Theory

    SciTech Connect

    D'Ariano, Giacomo Mauro

    2010-10-20

    The experience from Quantum Information of the last twenty years has lead theorists to look at Quantum Theory and the whole of Physics from a different angle. A new information-theoretic paradigm is emerging, long time ago prophesied by John Archibald Wheeler with his popular coinage 'It from bit'. Theoretical groups are now addressing the problem of deriving Quantum Theory from informational principles, and similar lines are investigated in new approaches to Quantum Gravity. In my talk I will review some recent advances on these lines. The general idea synthesizing the new paradigm is that there is only Quantum Theory (without quantization rules): the whole Physics--including space-time and relativity--is emergent from quantum-information processing. And, since Quantum Theory itself is made with purely informational principles, the whole Physics must be reformulated in information-theoretical terms. The review is divided into the following parts: (a) The informational axiomatization of Quantum Theory; (b) How space-time and relativistic covariance emerge from the quantum computation; (c) What is the information-theoretical meaning of inertial mass and Planck constant, and how the quantum field emerges; (d) Observational consequences: mass-dependent refraction index of vacuum. I then conclude with some possible future research lines.

  15. Reinventing Grounded Theory: Some Questions about Theory, Ground and Discovery

    ERIC Educational Resources Information Center

    Thomas, Gary; James, David

    2006-01-01

    Grounded theory's popularity persists after three decades of broad-ranging critique. In this article three problematic notions are discussed--"theory," "ground" and "discovery"--which linger in the continuing use and development of grounded theory procedures. It is argued that far from providing the epistemic security promised by grounded theory,…

  16. Reader Theories, Cognitive Theories and Educational Media Research.

    ERIC Educational Resources Information Center

    Becker, Ann

    This paper is the introduction to an inquiry into the relationship of post-structural reader theories to cognitive theories in the study of educational media. Basic concepts in reader and cognitive theories are defined, including the notions of "meaning" and "learners." Similarities and differences in the theories are described. It is suggested…

  17. Application of Information Integration Theory to Methodology of Theory Development.

    ERIC Educational Resources Information Center

    Shanteau, James

    Information integration theory (IIT) seeks to develop a unified theory of judgment and behavior. This theory provides a conceptual framework that has been applied to a variety of research areas including personality impression formation and decision making. In these applications information integration theory has helped to resolve methodological…

  18. 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'.

  19. Research in particle theory

    SciTech Connect

    Mansouri, F.; Suranyi, P; Wijewardhana, L.C.R.

    1991-10-01

    In the test particle approximation, the scattering amplitude for two-particle scattering in (2+1)-dimensional Chern-Simons-Witten gravity and supergravity was computed and compared to the corresponding metric solutions. The formalism was then extended to the exact gauge theoretic treatment of the two-particle scattering problem and compared to 't Hooft's results from the metric approach. We have studied dynamical symmetry breaking in 2+1 dimensional field theories. We have analyzed strong Extended Technicolor (ETC) models where the ETC coupling is close to a critical value. There are effective scalar fields in each of the theories. We have worked our how such scalar particles can be produced and how they decay. The {phi}{sup 4} field theory was investigated in the Schrodinger representation. The critical behavior was extracted in an arbitrary number of dimensions in second order of a systematic truncation approximation. The correlation exponent agrees with known values within a few percent.

  20. Density perturbation theory

    SciTech Connect

    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.

  1. Popper and nursing theory.

    PubMed

    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

  2. Research in particle theory

    SciTech Connect

    Mansouri, F.; Suranyi, P.; Wijewardhana, L.C.R.

    1992-10-01

    Dynamics of 2+1 dimensional gravity is analyzed by coupling matter to Chern Simons Witten action in two ways and obtaining the exact gravity Hamiltonian for each case. 't Hoot's Hamiltonian is obtained as an approximation. The notion of space-time emerges in the very end as a broken phase of the gauge theory. We have studied the patterns of discrete and continuous symmetry breaking in 2+1 dimensional field theories. We formulate our analysis in terms of effective composite scalar field theories. Point-like sources in the Chern-Simons theory of gravity in 2+1 dimensions are described by their Poincare' charges. We have obtained exact solutions of the constraints of Chern-Simons theory with an arbitrary number of isolated point sources in relative motion. We then showed how the space-time metric is constructed. A reorganized perturbation expansion with a propagator of soft infrared behavior has been used to study the critical behavior of the mass gap. The condition of relativistic covariance fixes the form of the soft propagator. Approximants to the correlation critical exponent were obtained in two loop order for the two and three dimensional theories. We proposed a new model of QED exhibiting two phases and a Majorana mass spectrum of single particle states. The model has a new source of coupling constant renormalization which opposes screening and suggests the model may confine. Assuming that the bound states of e{sup +}e{sup {minus}} essentially obey a Majorana spectrum, we obtained a consistent fit of the GSI peaks as well as predicting new peaks and their spin assignments.

  3. Splitting a default theory

    SciTech Connect

    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.

  4. Kinetic theory viscosity

    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.

  5. The electroweak theory

    SciTech Connect

    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.

  6. Management theory and applications.

    PubMed

    Fallon, L F

    2001-01-01

    Management is critical as an organization pursues its mission. There are many theories of management, but all agree that an effective organizational structure can facilitate the operation of a company. The author describes the typical functional areas found in most organizations (finance, operations, marketing, information systems, legal, and human resources); examines how the organization of tasks and people are inter-linked; and shows that administrators who have a working knowledge of management theory tend to be effective in the performance of their jobs. PMID:11401785

  7. Sequestering in String Theory

    SciTech Connect

    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.

  8. Salinas : theory manual.

    SciTech Connect

    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.

  9. 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.

  10. Many body theory program

    SciTech Connect

    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.

  11. 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…

  12. A new theory of gravity

    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.

  13. Theory of Modes and Impulses

    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…

  14. Edifying Theory: Serving the Good.

    ERIC Educational Resources Information Center

    Manen, Max van

    1982-01-01

    This article, concerning the importance of and need for educational theory, elucidates the etymology of the word "theory," describes the importance of ethnomethodology to educational principles, and views the concerns of epistemology to curriculum theory. The question "What is the good of theory?" is debated in relation to the actual benefit of…

  15. Evolutionary theory and teleology.

    PubMed

    O'Grady, R T

    1984-04-21

    The order within and among living systems can be explained rationally by postulating a process of descent with modification, effected by factors which are extrinsic or intrinsic to the organisms. Because at the time Darwin proposed his theory of evolution there was no concept of intrinsic factors which could evolve, he postulated a process of extrinsic effects--natural selection. Biological order was thus seen as an imposed, rather than an emergent, property. Evolutionary change was seen as being determined by the functional efficiency (adaptedness) of the organism in its environment, rather than by spontaneous changes in intrinsically generated organizing factors. The initial incompleteness of Darwin's explanatory model, and the axiomatization of its postulates in neo-Darwinism, has resulted in a theory of functionalism, rather than structuralism. As such, it introduces an unnecessary teleology which confounds evolutionary studies and reduces the usefulness of the theory. This problem cannot be detected from within the neo-Darwinian paradigm because the different levels of end-directed activity--teleomatic, teleonomic, and teleological--are not recognized. They are, in fact, considered to influence one another. The theory of nonequilibrium evolution avoids these problems by returning to the basic principles of biological order and developing a structuralist explanation of intrinsically generated change. Extrinsic factors may affect the resultant evolutionary pattern, but they are neither necessary nor sufficient for evolution to occur.

  16. Personality Theory and TESOL

    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…

  17. 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…

  18. ADVANCES IN IMPEDANCE THEORY

    SciTech Connect

    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.

  19. 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…

  20. Generalizability Theory [Book Review].

    ERIC Educational Resources Information Center

    Kane, Michael

    2003-01-01

    This book presents a comprehensive overview of univariate and multivariate generalizability theory, a psychometric model that provides a powerful approach to the analysis of errors of measurement through the use of random-effects and mixed-model analysis of variance. (SLD)

  1. Postmodern Test Theory

    ERIC Educational Resources Information Center

    Mislevy, Robert J.

    2014-01-01

    Background/Context: This article explains the idea of a neopragmatic postmodernist test theory and offers some thoughts about what changing notions concerning the nature of and meanings assigned to knowledge imply for educational assessment, present and future. Purpose: Advances in the learning sciences--particularly situative and sociocognitive…

  2. 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…

  3. AP Music Theory Applied

    ERIC Educational Resources Information Center

    Spieker, Matthew H.

    2016-01-01

    Some American high schools include Advanced Placement (AP) Music Theory within their course offerings. Students who pass the AP exam can receive college credit either as a music or humanities credit. An AP class, however, offers music students more than future college credit; it ultimately improves musicianship skills and promotes deeper…

  4. Variational transition state theory

    SciTech Connect

    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.

  5. New Theory of Flight

    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.

  6. Game theory of mind.

    PubMed

    Yoshida, Wako; Dolan, Ray J; Friston, Karl J

    2008-12-01

    This paper introduces a model of 'theory of mind', namely, how we represent the intentions and goals of others to optimise our mutual interactions. We draw on ideas from optimum control and game theory to provide a 'game theory of mind'. First, we consider the representations of goals in terms of value functions that are prescribed by utility or rewards. Critically, the joint value functions and ensuing behaviour are optimised recursively, under the assumption that I represent your value function, your representation of mine, your representation of my representation of yours, and so on ad infinitum. However, if we assume that the degree of recursion is bounded, then players need to estimate the opponent's degree of recursion (i.e., sophistication) to respond optimally. This induces a problem of inferring the opponent's sophistication, given behavioural exchanges. We show it is possible to deduce whether players make inferences about each other and quantify their sophistication on the basis of choices in sequential games. This rests on comparing generative models of choices with, and without, inference. Model comparison is demonstrated using simulated and real data from a 'stag-hunt'. Finally, we note that exactly the same sophisticated behaviour can be achieved by optimising the utility function itself (through prosocial utility), producing unsophisticated but apparently altruistic agents. This may be relevant ethologically in hierarchal game theory and coevolution.

  7. Durkheim's Theory of Anomie

    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…

  8. (Mathematics and string theory)

    SciTech Connect

    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.

  9. Literary Theory: A Pedagogy.

    ERIC Educational Resources Information Center

    Bacon, Roger Lee

    This dissertation dealt with the preparation, designing, teaching, and evaluation of a course in literary theory. The course examined the following areas of literary study: definition, perception, description, explication, interpretation, and evaluation. It is centered on the following theses: (1) in literary pursuits criticism is teaching and…

  10. Theory of orthodontic motions

    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.

  11. Benchmarking nuclear fission theory

    DOE PAGESBeta

    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.

  12. Intuitive Test Theory

    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…

  13. Informed Grounded Theory

    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…

  14. Improved equivalent source theory.

    PubMed

    Umul, Yusuf Z

    2009-08-01

    The equivalent source theorem, which is an important technique in the study of radiation and scattering by apertures, is improved by using the two axioms of the modified theory of physical optics. The method is applied to the problem of radiation of electromagnetic waves by a parallel plate waveguide. The results are investigated numerically.

  15. Quantum theory of friction

    SciTech Connect

    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.

  16. William James's Moral Theory

    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…

  17. Canonical field theory

    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.

  18. 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;…

  19. Sustaining Writing Theory

    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…

  20. Personality Theory and TESOL

    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…

  1. Potential theory of radiation

    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.

  2. 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…

  3. 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.

  4. What Is Theory?

    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…

  5. Teaching Bohr Theory.

    ERIC Educational Resources Information Center

    Latimer, Colin J.

    1983-01-01

    Discusses some lesser known examples of atomic phenomena to illustrate to students that the old quantum theory in its simplest (Bohr) form is not an antiquity but can still make an important contribution to understanding such phenomena. Topics include hydrogenic/non-hydrogenic spectra and atoms in strong electric and magnetic fields. (Author/JN)

  6. Game Theory of Mind

    PubMed Central

    Yoshida, Wako; Dolan, Ray J.; Friston, Karl J.

    2008-01-01

    This paper introduces a model of ‘theory of mind’, namely, how we represent the intentions and goals of others to optimise our mutual interactions. We draw on ideas from optimum control and game theory to provide a ‘game theory of mind’. First, we consider the representations of goals in terms of value functions that are prescribed by utility or rewards. Critically, the joint value functions and ensuing behaviour are optimised recursively, under the assumption that I represent your value function, your representation of mine, your representation of my representation of yours, and so on ad infinitum. However, if we assume that the degree of recursion is bounded, then players need to estimate the opponent's degree of recursion (i.e., sophistication) to respond optimally. This induces a problem of inferring the opponent's sophistication, given behavioural exchanges. We show it is possible to deduce whether players make inferences about each other and quantify their sophistication on the basis of choices in sequential games. This rests on comparing generative models of choices with, and without, inference. Model comparison is demonstrated using simulated and real data from a ‘stag-hunt’. Finally, we note that exactly the same sophisticated behaviour can be achieved by optimising the utility function itself (through prosocial utility), producing unsophisticated but apparently altruistic agents. This may be relevant ethologically in hierarchal game theory and coevolution. PMID:19112488

  7. 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.

  8. 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)

  9. 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.

  10. From Practice to Theory.

    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)

  11. Theory. [SITE 2002 Section].

    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…

  12. Theories of language acquisition.

    PubMed

    Vetter, H J; Howell, R W

    1971-03-01

    Prior to the advent of generative grammar, theoretical approaches to language development relied heavily upon the concepts ofdifferential reinforcement andimitation. Current studies of linguistic acquisition are largely dominated by the hypothesis that the child constructs his language on the basis of a primitive grammar which gradually evolves into a more complex grammar. This approach presupposes that the investigator does not impose his own grammatical rules on the utterances of the child; that the sound system of the child and the rules he employs to form sentences are to be described in their own terms, independently of the model provided by the adult linguistic community; and that there is a series of steps or stages through which the child passes on his way toward mastery of the adult grammar in his linguistic environment. This paper attempts to trace the development of human vocalization through prelinguistic stages to the development of what can be clearly recognized as language behavior, and then progresses to transitional phases in which the language of the child begins to approximate that of the adult model. In the view of the authors, the most challenging problems which confront theories of linguistic acquisition arise in seeking to account for structure of sound sequences, in the rules that enable the speaker to go from meaning to sound and which enable the listener to go from sound to meaning. The principal area of concern for the investigator, according to the authors, is the discovery of those rules at various stages of the learning process. The paper concludes with a return to the question of what constitutes an adequate theory of language ontogenesis. It is suggested that such a theory will have to be keyed to theories of cognitive development and will have to include and go beyond a theory which accounts for adult language competence and performance, since these represent only the terminal stage of linguistic ontogenesis.

  13. Baryonic condensates on the conifold

    NASA Astrophysics Data System (ADS)

    Benna, Marcus K.; Dymarsky, Anatoly; Klebanov, Igor R.

    2007-08-01

    We provide new evidence for the gauge/string duality between the baryonic branch of the cascading SU(k(M+1)) × SU(kM) gauge theory and a family of type IIB flux backgrounds based on warped products of the deformed conifold and Bbb R3,1. We show that a Euclidean D5-brane wrapping all six deformed conifold directions can be used to measure the baryon expectation values, and present arguments based on κ-symmetry and the equations of motion that identify the gauge bundles required to ensure worldvolume supersymmetry of this object. Furthermore, we investigate its coupling to the pseudoscalar and scalar modes associated with the phase and magnitude, respectively, of the baryon expectation value. We find that these massless modes perturb the Dirac-Born-Infeld and Chern-Simons terms of the D5-brane action in a way consistent with our identification of the baryonic condensates. We match the scaling dimension of the baryon operators computed from the D5-brane action with that found in the cascading gauge theory. We also derive and numerically evaluate an expression that describes the variation of the baryon expectation values along the supergravity dual of the baryonic branch.

  14. DBI Galileons in the Einstein frame: Local gravity and cosmology

    NASA Astrophysics Data System (ADS)

    Zumalacárregui, Miguel; Koivisto, Tomi S.; Mota, David F.

    2013-04-01

    It is shown that a disformally coupled theory in which the gravitational sector has the Einstein-Hilbert form is equivalent to a quartic Dirac-Born-Infeld Galileon Lagrangian, possessing nonlinear higher derivative interactions, and hence allowing for the Vainshtein effect. This Einstein frame description considerably simplifies the dynamical equations and highlights the role of the different terms. The study of highly dense, nonrelativistic environments within this description unravels the existence of a disformal screening mechanism, while the study of static vacuum configurations reveals the existence of a Vainshtein radius, at which the asymptotic solution breaks down. Disformal couplings to matter also allow the construction of dark energy models, which behave differently than conformally coupled ones and introduce new effects on the growth of large scale structure over cosmological scales, on which the scalar force is not screened. We consider a simple disformally coupled dark matter model in detail, in which standard model particles follow geodesics of the gravitational metric and only dark matter is affected by the disformal scalar field. This particular model is not compatible with observations in the linearly perturbed regime. Nonetheless, disformally coupled theories offer enough freedom to construct realistic cosmological scenarios, which can be distinguished from the standard model through characteristic signatures.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Partially invariant solutions of models obtained from the Nambu-Goto action

    NASA Astrophysics Data System (ADS)

    Grundland, A. M.; Hariton, A. J.

    2004-08-01

    The concept of partially invariant solutions is discussed in the framework of the group analysis of models derived from the Nambu-Goto action. In particular, we consider the nonrelativistic Chaplygin gas and the relativistic Born-Infeld theory for a scalar field. Using a general systematic approach based on subgroup classification methods, nontrivial partially invariant solutions with defect structure δ=1 are constructed. For this purpose, a classification of the subgroups of the Lie point symmetry group, which have generic orbits of dimension 2, has been performed. These subgroups allow us to introduce the corresponding symmetry variables and next to reduce the initial equations to different nonequivalent classes of partial differential equations and ordinary differential equations. The latter can be transformed to standard form and, in some cases, solved in terms of elementary and Jacobi elliptic functions. This results in a large number of new partially invariant solutions, which are determined to be either reducible or irreducible with respect to the symmetry group. Some physical interpretation of the results in the area of fluid dynamics and field theory are discussed. The solutions represent traveling and centered waves, algebraic solitons, kinks, bumps, cnoidal and snoidal waves.

  20. Dark D-brane cosmology

    SciTech Connect

    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.

  1. The degeneracy problem in non-canonical inflation

    SciTech Connect

    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.

  2. Geometry from Gauge Theory

    SciTech Connect

    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.

  3. Vector theories in cosmology

    SciTech Connect

    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.

  4. Redox theory of aging

    PubMed Central

    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

  5. Theory in vivo.

    PubMed

    Duncan, D

    1993-02-01

    Due to a formerly held assumption that psychoanalytic theories operate exclusively in the positivistic manner associated with the natural sciences, current thinking on how they operate specifically or in their own terms is addressing a long-neglected task. In this paper it is suggested that inherent and acquired modes of theorizing interplay when an analyst is working; and that a dialogue involving these two modes which began in Freud's inner life has evolved into our communal conceptual discourse. A series of situationally connected interchanges with a female analysand, over a two-week period, is presented. An attempt is made to demonstrate some theorizing, not 'in vitro'--'in the test-tube' of abstraction, but where most use and discovery of theory happens, 'in vivo'--within the living experience of therapeutic analysis. PMID:8454402

  6. Panarchy: theory and application

    USGS Publications Warehouse

    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.

  7. Concepts and folk theories

    PubMed Central

    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

  8. Salinas : theory manual.

    SciTech Connect

    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.

  9. Degenerate density perturbation theory

    NASA Astrophysics Data System (ADS)

    Palenik, Mark C.; Dunlap, Brett I.

    2016-09-01

    Fractional occupation numbers can be used in density functional theory to create a symmetric Kohn-Sham potential, resulting in orbitals with degenerate eigenvalues. We develop the corresponding perturbation theory and apply it to a system of Nd degenerate electrons in a harmonic oscillator potential. The order-by-order expansions of both the fractional occupation numbers and unitary transformations within the degenerate subspace are determined by the requirement that a differentiable map exists connecting the initial and perturbed states. Using the X α exchange-correlation (XC) functional, we find an analytic solution for the first-order density and first- through third-order energies as a function of α , with and without a self-interaction correction. The fact that the XC Hessian is not positive definite plays an important role in the behavior of the occupation numbers.

  10. Dielectronic recombination theory

    SciTech Connect

    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.

  11. Situational theory of leadership.

    PubMed

    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.

  12. k/not theory.

    PubMed

    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.

  13. Physics and proof theory

    PubMed Central

    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

  14. Predictive Game Theory

    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.

  15. The Least Particle Theory

    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.

  16. k/not theory.

    PubMed

    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

  17. Fairbairn's Theory of Change.

    PubMed

    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

  18. Constructor theory of information

    PubMed Central

    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

  19. Studies in clustering theory

    NASA Astrophysics Data System (ADS)

    Stell, George

    In recent years the properties of percolation models have been studied intensively. The purpose of our project was to develop a general theory of percolation and clustering between particles of arbitrary size and shape, with arbitrary correlations between them. The goal of such a theory includes the treatment of continuum percolation as well as a novel treatment of lattice percolation. We made substantial progress toward this goal. The quantities basic to a description of clustering, the mean cluster size, mean number of clusters, etc., were developed. Concise formulas were given for the terms in such series, and proved, at least for sufficiently low densities, that the series are absolutely convergent. These series can now be used to construct Pade approximants that will allow one to probe the percolation transition. A scaled-particle theory of percolation was developed which gives analytic approximants for the mean number of clusters in a large class of two and three dimensional percolation models. Although this quantity is essential in many applications, e.g., explaining colligative properties, and interpreting low-angle light-scattering data, no systematic studies of it have been done before this work. Recently carried out detailed computer simulations show that the mean number of clusters is given to high accuracy by several of there approximations. Extensions of this work will allow calculation of the complete cluster size distribution.

  20. The Theories of Turbulence

    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.

  1. Immunology's theories of cognition.

    PubMed

    Tauber, Alfred I

    2013-01-01

    Contemporary immunology has established its fundamental theory as a biological expression of personal identity, wherein the "immune self" is defended by the immune system. Protection of this agent putatively requires a cognitive capacity by which the self and the foreign are perceived and thereby discriminated; from such information, discernment of the environment is achieved and activation of pathways leading to an immune response may be initiated. This so-called cognitive paradigm embeds such functions as "perception," "recognition," "learning," and "memory" to characterize immune processes, but the conceptual character of such functions has meanings that vary with the particular theory adopted. When different formulations of cognition are considered, immunology's conceptual infrastructure shifts: Extensions of conventional psychological understanding of representational cognition based on a subject-object dichotomy support notions of immune agency; alternatively, formulations of perception that dispense with representations and attendant notions of agency reconfigure the predicate epistemology dominating current immune theory. Reviewing immunological literature of the past five decades, these two understandings of perception--representational and non-representational (considered here from ecological, enactivist, and autopoietic perspectives)--offer competing views of immune cognitive functions. These, in turn, provide competing philosophical understandings of immunology's conceptual foundations, which reflect parallel controversies dominating current debates in philosophy of mind and attendant discussions about personal identity.

  2. Fairbairn's Theory of Change.

    PubMed

    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.

  3. Probabilistic theories with purification

    SciTech Connect

    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.

  4. Beyond mean field theory: statistical field theory for neural networks

    PubMed Central

    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

  5. 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…

  6. 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…

  7. Why Generalizability Theory Yields Better Results than Classical Test Theory.

    ERIC Educational Resources Information Center

    Eason, Sandra H.

    Generalizability theory provides a technique for accurately estimating the reliability of measurements. The power of this theory is based on the simultaneous analysis of multiple sources of error variances. Equally important, generalizability theory considers relationships among the sources of measurement error. Just as multivariate inferential…

  8. Linear Theory, Dimensional Theory, and the Face-Inversion Effect

    ERIC Educational Resources Information Center

    Loftus, Geoffrey R.; Oberg, Martin A.; Dillon, Allyss M.

    2004-01-01

    We contrast 2 theories within whose context problems are conceptualized and data interpreted. By traditional linear theory, a dependent variable is the sum of main-effect and interaction terms. By dimensional theory, independent variables yield values on internal dimensions that in turn determine performance. We frame our arguments within an…

  9. Superspace version of BF theories

    SciTech Connect

    Aidaoui, A.; Tahiri, M.

    2012-06-27

    The BF theory is presented in a superspace formalism. This permits us to see that the necessary fields of the quantized theory enlarged with auxiliary fields naturally occur and lead to a BRST-VSUY exact quantum action.

  10. 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)

  11. Thoughts About Theories and Statistics.

    PubMed

    Fawcett, Jacqueline

    2015-07-01

    The purpose of this essay is to share my ideas about the connection between theories and statistics. The essay content reflects my concerns about some researchers' and readers' apparent lack of clarity about what constitutes appropriate statistical testing and conclusions about the empirical adequacy of theories. The reciprocal relation between theories and statistics is emphasized and the conclusion is that statistics without direction from theory is no more than a hobby.

  12. Modern Biological Theories of Aging

    PubMed Central

    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

  13. A new theory of gravity.

    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.

  14. 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

  15. The Chaos Theory of Careers.

    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)

  16. A Theory of Memory Retrieval

    ERIC Educational Resources Information Center

    Ratcliff, Roger

    1978-01-01

    Cognitive psychology lacks explicit theories that encompass more than a single experimental paradigm. This research presents a theory of memory retrieval that not only applies over a range of paradigms but also deals with experimental data in greater depth and more detail than competing models. The theory provides a rationale for relating…

  17. Goal Theory and Individual Productivity.

    ERIC Educational Resources Information Center

    Frost, Peter J.

    The paper provides a review of goal theory as articulated by Edwin Locke. The theory is evaluated in terms of laboratory and field research and its practical usefulnes is explored as a means to improving individual productivity in "real world" organizations Research findings provide support for some goal theory propositions but suggest also the…

  18. 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…

  19. 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.

  20. 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…

  1. 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…

  2. Time Machines and Quantum Theory

    NASA Astrophysics Data System (ADS)

    Hadley, Mark J.

    2008-09-01

    There is a deep structural link between acausal spacetimes and quantum theory. As a consequence quantum theory may resolve some "paradoxes" of time travel. Conversely, non-time-orientable spacetimes naturally give rise to electric charges and spin half. If an explanation of quantum theory is possible, then general relativity with time travel could it.

  3. 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…

  4. Comments on quantum probability theory.

    PubMed

    Sloman, Steven

    2014-01-01

    Quantum probability theory (QP) is the best formal representation available of the most common form of judgment involving attribute comparison (inside judgment). People are capable, however, of judgments that involve proportions over sets of instances (outside judgment). Here, the theory does not do so well. I discuss the theory both in terms of descriptive adequacy and normative appropriateness.

  5. In Defense of Darwin's Theory.

    ERIC Educational Resources Information Center

    Naylor, Bruce G.; Handford, Paul

    1985-01-01

    Examines issues regarding the defensibility and utility of natural selection as a scientific theory, focusing on the process of population change over time. Topics considered include criticisms of Darwinian theory, tautology and the meaning of fitness, the ability of theories to predict and explain, and the sufficiency of natural selection. (DH)

  6. Reconsidering Moore's Transactional Distance Theory

    ERIC Educational Resources Information Center

    Giossos, Yiannis; Koutsouba, Maria; Lionarakis, Antonis; Skavantzos, Kosmas

    2009-01-01

    One of the core theories of distance education is Michael Graham Moore's "Theory of Transactional Distance" that provides the broad framework of the pedagogy of distance education and allows the generation of almost infinite number of hypotheses for research. However, the review of the existing studies relating to the theory showed the use of a…

  7. Informational derivation of quantum theory

    SciTech Connect

    Chiribella, Giulio; D'Ariano, Giacomo Mauro; Perinotti, Paolo

    2011-07-15

    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.

  8. Crosslinkage theory of senile cataracts.

    PubMed

    Bellows, J G; Bellows, R T

    1976-02-01

    The theory of crosslinkage as a cause of aging of all living organic tissues has withstood the test of time. Nearly all the past theories of senile cataract formation contain elements involving a potent crosslinking agent. Therefore crosslinkage may now be recognized as the common denominator in past theories of senile cataracts. This paper proposes that crosslinkage is the mechanism for senile cataract formation.

  9. 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.…

  10. 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.)

  11. [From the cell theory to the neuron theory].

    PubMed

    Tixier-Vidal, Andrée

    2010-01-01

    The relationship between the cell theory formulated by Schwann (1839) and by Virchow (1855) on the one hand, and, on the other hand, the neuron theory, as formulated by Waldeyer (1891) and by Cajal (1906), are discussed from a historical point of view. Both of them are the result of technical and conceptuel progress. Both of them had to fight against the dominant dogma before being accepted. The cell theory opposed the school of Bichat, the vitalist philosophy and the positivist philosophy of Auguste Comte. The neuron theory, which is clearly based on the cell theory, was mostly concerned with the mode of interneuronal communication; it opposed the concept of contiguity to Golgi's concept of continuity. At present, the cell theory remains central in every field of Biology. By contrast, the neuron theory, which until the middle of the XXth century opened the study of the nervous system to a necessary reductionnist approach, is no longer central to recent developments of neurosciences.

  12. Sintering Theory and Practice

    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

  13. 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

  14. Cosmic microwave background theory.

    PubMed

    Bond, J R

    1998-01-01

    A long-standing goal of theorists has been to constrain cosmological parameters that define the structure formation theory from cosmic microwave background (CMB) anisotropy experiments and large-scale structure (LSS) observations. The status and future promise of this enterprise is described. Current band-powers in -space are consistent with a DeltaT flat in frequency and broadly follow inflation-based expectations. That the levels are approximately (10(-5))2 provides strong support for the gravitational instability theory, while the Far Infrared Absolute Spectrophotometer (FIRAS) constraints on energy injection rule out cosmic explosions as a dominant source of LSS. Band-powers at 100 suggest that the universe could not have re-ionized too early. To get the LSS of Cosmic Background Explorer (COBE)-normalized fluctuations right provides encouraging support that the initial fluctuation spectrum was not far off the scale invariant form that inflation models prefer: e.g., for tilted Lambda cold dark matter sequences of fixed 13-Gyr age (with the Hubble constant H0 marginalized), ns = 1.17 +/- 0.3 for Differential Microwave Radiometer (DMR) only; 1.15 +/- 0.08 for DMR plus the SK95 experiment; 1.00 +/- 0.04 for DMR plus all smaller angle experiments; 1.00 +/- 0.05 when LSS constraints are included as well. The CMB alone currently gives weak constraints on Lambda and moderate constraints on Omegatot, but theoretical forecasts of future long duration balloon and satellite experiments are shown which predict percent-level accuracy among a large fraction of the 10+ parameters characterizing the cosmic structure formation theory, at least if it is an inflation variant.

  15. A theory of deterrence

    SciTech Connect

    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.

  16. Theory and spectroscopy

    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.

  17. Modular headache theory.

    PubMed

    Young, W B; Peres, M F; Rozen, T D

    2001-10-01

    Many people experience headaches that do not fulfil the International Headache Society's criteria for a specific headache disorder yet behave biologically like that disorder. Others fulfil criteria for one headache disorder and yet have features of another disorder. To explain these observations, we propose that groups of neurones called modules become activated to produce each symptom of a primary headache disorder, and that each module is linked to other modules that together produce an individual's headache. This theory has implications for the classification, research and treatment of primary and secondary headache patients.

  18. Curved shock theory

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2016-07-01

    Curved shock theory (CST) is introduced, developed and applied to relate pressure gradients, streamline curvatures, vorticity and shock curvatures in flows with planar or axial symmetry. Explicit expressions are given, in an influence coefficient format, that relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. The effect of pre-shock flow divergence/convergence, on vorticity generation, is related to the transverse shock curvature. A novel derivation for the post-shock vorticity is presented that includes the effects of pre-shock flow non-uniformities. CST applicability to unsteady flows is discussed.

  19. Theory of wing rock

    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.

  20. 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.

  1. Greek theories on eugenics.

    PubMed

    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.

  2. Theory of gearing

    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.

  3. Theory and modeling group

    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.

  4. Gradient equivalent crystal theory.

    PubMed

    Zypman, F R; Ferrante, J

    2006-07-01

    This paper presents an extension of the formalism of equivalent crystal theory (ECT) by introducing an electron density gradient term so that the total model density becomes a more accurate representation of the real local density. Specifically, we allow for the electron density around a lattice site to have directionality, in addition to an average value, as assumed in ECT. We propose that an atom senses its neighbouring density as a weighted sum-the weights given by the its own electronic probability. As a benchmark, the method is used to compute vacancy migration energy curves of iron. These energies are in good agreement with previously published results. PMID:21690822

  5. Nucleus from string theory

    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.

  6. Comparison of satellite theories

    NASA Technical Reports Server (NTRS)

    Hertz, H. G.

    1972-01-01

    The accuracy of five mathematical models in computing a nominal orbit for the Vanguard 2 satellite by using a position velocity vector is considered. Either numerical integration or analytical theories are used in all models as well as the same force model that corresponds to a potential with the zonal harmonics to order four. The amounts of spread in the values of the total energy and the z-component of the angular momentum for a set of times are considered as measures of accuracy.

  7. Neutrinos: Theory and Phenomenology

    SciTech Connect

    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.

  8. Toward an Integrated Theory of Play.

    ERIC Educational Resources Information Center

    Frost, Joe L.

    Beginning with an extensive overview of theories, this paper proposes an integrative perspective on play. Early theories, which were proposed in the last half of the 19th century, included the surplus energy theory, the recapitulation theory, the instinct-practice theory, and the relaxation theory. More recent theories of play include Freud's and…

  9. [Polyvagal theory and emotional trauma].

    PubMed

    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

  10. 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.

  11. Quantum field theory of fluids.

    PubMed

    Gripaios, Ben; Sutherland, Dave

    2015-02-20

    The quantum theory of fields is largely based on studying perturbations around noninteracting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is "freer", in the sense that the noninteracting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree and loop level, we give evidence that a quantum perfect fluid can be consistently formulated as a low-energy, effective field theory. We speculate that the quantum behavior is radically different from both classical fluids and quantum fields.

  12. Recent developments in superstring theory

    PubMed Central

    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

  13. Recent developments in superstring theory.

    PubMed

    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.

  14. 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.

  15. Endochronic theory of dynamic viscoplasticity

    SciTech Connect

    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.

  16. Nuclear Theory - Nuclear Power

    NASA Astrophysics Data System (ADS)

    Svenne, J. P.; Canton, L.; Kozier, K. S.

    2008-01-01

    The results from modern nuclear theory are accurate and reliable enough to be used for practical applications, in particular for scattering that involves few-nucleon systems of importance to nuclear power. Using well-established nucleon-nucleon (NN) interactions that fit well the NN scattering data, and the AGS form of the three-body theory, we have performed precise calculations of low-energy neutron-deuteron (n+d) scattering. We show that three-nucleon force effects that have impact on the low-energy vector analyzing powers have no practical effects on the angular distribution of the n+d cross-section. There appear to be problems for this scattering in the evaluated nuclear data file (ENDF) libraries, at the incident neutron energies less than 3.2 MeV. Supporting experimental data in this energy region are rather old (>25 years), sparse and often inconsistent. Our three-body results at low energies, 50 keV to 10.0 MeV, are compared to the ENDF/B-VII.0 and JENDL (Japanese Evaluated Nuclear Data Library) -3.3 evaluated angular distributions. The impact of these results on the calculated reactivity for various critical systems involving heavy water is shown.

  17. Deadman theory revisited12.

    PubMed

    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

  18. Aspects of Quantum Theory

    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.

  19. [Psychological theories of motivation].

    PubMed

    Quoniam, Nolwenn; Bungener, Catherine

    2004-03-01

    The comprehension of the principles guiding the human actions has always been an important aspect of philosophy. The development of experimental psychology first completely rejected all mental explanations such as will, intentions or motives. Behavior should then only be understood as determined by conditioning and learning. However, different theories denied that human behavior could be considered as purely reactive to the environment and stressed the active role of the organism on the environment. Theories from the humanist psychology and the social psychology described two kinds of motivation. The extrinsic motivation results from external stimuli and the intrinsic motivation from the organism himself. Our behavior is therefore determined by an interaction between our beliefs, expectations, needs and the environment. Actually, the concept of motivation is not well specified. It refers either to a global dynamic structure responsible for action either to a specific tendency toward some specific actions. Anyway, motivation is a concept infered from behavior. Therefore, its evaluation could only be secondary. PMID:15683964

  20. Consistent Quantum Theory

    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

  1. Disorder in large- N theories

    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.

  2. Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

    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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

    SciTech Connect

    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.

  10. Observer Localization in Multiverse Theories

    NASA Astrophysics Data System (ADS)

    Hutter, Marcus

    2011-11-01

    The progression of theories suggested for our world, from ego- to geo- to helio-centric models to universe and multiverse theories and beyond, shows one tendency: The size of the described worlds increases, with humans being expelled from their center to ever more remote and random locations. If pushed too far, a potential theory of everything (TOE) is actually more a theories of nothing (TON). Indeed such theories have already been developed. I show that including observer localization into such theories is necessary and su_cient to avoid this problem. I develop a quantitative recipe to identify TOEs and distinguish them from TONs and theories in-between. This precisely shows what the problem is with some recently suggested universal TOEs.

  11. Forgetting and remembering alienation theory.

    PubMed

    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.

  12. Forgetting and remembering alienation theory.

    PubMed

    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

  13. Relevance theory: pragmatics and cognition.

    PubMed

    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.

  14. Changing theories of change: strategic shifting in implicit theory endorsement.

    PubMed

    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

  15. Changing theories of change: strategic shifting in implicit theory endorsement.

    PubMed

    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.

  16. DUSEL Theory White Paper

    SciTech Connect

    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

  17. Topics in Double Field Theory

    NASA Astrophysics Data System (ADS)

    Kwak, Seung Ki

    The existence of momentum and winding modes of closed string on a torus leads to a natural idea that the field theoretical approach of string theory should involve winding type coordinates as well as the usual space-time coordinates. Recently developed double field theory is motivated from this idea and it implements T-duality manifestly by doubling the coordinates. In this thesis we will mainly focus on the double field theory formulation of different string theories in its low energy limit: bosonic, heterotic, type II and its massive extensions, and N = 1 supergravity theory. In chapter 2 of the thesis we study the equivalence of different formulations of double field theory. There are three different formulations of double field theory: background field E formulation, generalized metric H formulation, and frame field EAM formulation. Starting from the frame field formalism and choosing an appropriate gauge, the equivalence of the three formulations of bosonic theory are explicitly verified. In chapter 3 we construct the double field theory formulation of heterotic strings. The global symmetry enlarges to O( D, D + n) for heterotic strings and the enlarged generalized metric features this symmetry. The structural form of bosonic theory can directly be applied to the heterotic theory with the enlarged generalized metric. In chapter 4 we develop a unified framework of double field theory for type II theories. The Ramond-Ramond potentials fit into spinor representations of the duality group O( D, D) and the theory displays Spin+( D, D) symmetry with its self-duality relation. For a specific form of RR 1-form the theory reduces to the massive deformation of type IIA theory due to Romans. In chapter 5 we formulate the N = 1 supersymmetric extension of double field theory including the coupling to n abelian vector multiplets. This theory features a local O(1, 9 + n) x O(1, 9) tangent space symmetry under which the fermions transform. (Copies available exclusively from

  18. 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).

  19. 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.

  20. "Reinforcement" in behavior theory.

    PubMed

    Schoenfeld, W N

    1978-01-01

    In its Pavlovian context, "reinforcement" was actually a descriptive term for the functional relation between an unconditional and a conditional stimulus. When it was adopted into operant conditioning, "reinforcement" became the central concept and the key operation, but with new qualifications, new referents, and new expectations. Some behavior theorists believed that "reinforcers" comprise a special and limited class of stimuli or events, and they speculated about what the essential "nature of reinforcement" might be. It is now known that any stimulus can serve a reinforcing function, with due recognition of such parameters as subject species characteristics, stimulus intensity, sensory modality, and schedule of application. This paper comments on these developments from the standpoint of reflex behavior theory.

  1. "Reinforcement" in behavior theory.

    PubMed

    Schoenfeld, W N

    1995-01-01

    In its Pavlovian context, "reinforcement" was actually a descriptive term for the functional relation between an unconditional and a conditional stimulus. When it was adopted into operant conditioning, "reinforcement" became the central concept and the key operation, but with new qualifications, new referents, and new expectations. Some behavior theorists believed that "reinforcers" comprise a special and limited class of stimuli or events, and they speculated about what the essential "nature of reinforcement" might be. It is now known that any stimulus can serve a reinforcing function, with due recognition of such parameters as subject species characteristics, stimulus intensity, sensory modality, and schedule of application. This paper comments on these developments from the stand-point of reflex behavior theory.

  2. Vulvodynia. Theory and management.

    PubMed

    Ridley, C M

    1998-10-01

    Vulvodynia, defined as vulval pain, soreness or burning as opposed to itching or pruritus, is a common and important problem. Although not a sexually transmitted disease, it often presents to physicians working in that field. The main groups of vulvodynia are those where the symptoms are the consequence of an active dermatosis or infection, and those where it is not attributable to such conditions. In the latter group, the patients fall into two main categories: those of dysesthetic vulvidynia, with constant unprovoked pain, and vulval vestibulitis, with pain provoked by attempted vaginal entry. The recent realization that dysesthetic vulvodynia and vulval vestibulitis may be regarded as pain syndromes is proving a fruitful concept as regards both theory and management of these troublesome conditions.

  3. Crack layer theory

    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.

  4. Commitment to health theory.

    PubMed

    Kelly, Cynthia W

    2008-01-01

    This article introduces commitment to health as a middle-range. Commitment to health (CTH) is derived from Prochaska and DiClemente's (1983) Transtheoretical Model of Behavior Change. CTH theory is designed to predict the likelihood of behavior change between the action and maintenance stages of change. Commitment is defined as a freely chosen internal resolve to perform health behaviors, even when encumbered or inconvenienced by difficulties. Health is defined as the optimal level of well-being. Commitment is an independent continuous variable, but it can be categorized into three time-oriented categories: (1) low-level, (2) middle-level, and (3) high-level commitment. The higher the level of commitment, the more likely the individual will adopt long-term behavior change. This article presents the definitions, assumptions, and relational statements of CTH.

  5. Theory of wing rock

    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.

  6. Classical Information Theory

    NASA Astrophysics Data System (ADS)

    Suhov, Y.

    We begin with the definition of information gained by knowing that an event A has occurred: iota (A) = -log_2 {{P}}(A). (A dual point of view is also useful (although more evasive), where iota (A) is the amount of information needed to specify event A.) Here and below {{P}} stands for the underlying probability distribution. So the rarer an event A, the more information we gain if we know it has occurred. (More broadly, the rarer an event A, the more impact it will have. For example, the unlikely event that occurred in 1938 when fishermen caught a coelacanth - a prehistoric fish believed to be extinct - required a significant change to beliefs about evolution and biology. On the other hand, the likely event of catching a herring or a tuna would hardly imply any change in theories.)

  7. Axions in String Theory

    SciTech Connect

    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.

  8. Chinese implicit leadership theory.

    PubMed

    Ling, W; Chia, R C; Fang, L

    2000-12-01

    In a 1st attempt to identify an implicit theory of leadership among Chinese people, the authors developed the Chinese Implicit Leadership Scale (CILS) in Study 1. In Study 2, they administered the CILS to 622 Chinese participants from 5 occupation groups, to explore differences in perceptions of leadership. Factor analysis yielded 4 factors of leadership: Personal Morality, Goal Efficiency, Interpersonal Competence, and Versatility. Social groups differing in age, gender, education level, and occupation rated these factors. Results showed no significant gender differences, and the underlying cause for social group differences was education level. All groups gave the highest ratings to Interpersonal Competence, reflecting the enormous importance of this factor, which is consistent with Chinese collectivist values.

  9. Greek theories on eugenics.

    PubMed Central

    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

  10. Theory of edge detection.

    PubMed

    Marr, D; Hildreth, E

    1980-02-29

    A theory of edge detection is presented. The analysis proceeds in two parts. (1) Intensity changes, which occur in a natural image over a wide range of scales, are detected separately at different scales. An appropriate filter for this purpose at a given scale is found to be the second derivative of a Gaussian, and it is shown that, provided some simple conditions are satisfied, these primary filters need not be orientation-dependent. Thus, intensity changes at a given scale are best detected by finding the zero values of delta 2G(x,y)*I(x,y) for image I, where G(x,y) is a two-dimensional Gaussian distribution and delta 2 is the Laplacian. The intensity changes thus discovered in each of the channels are then represented by oriented primitives called zero-crossing segments, and evidence is given that this representation is complete. (2) Intensity changes in images arise from surface discontinuities or from reflectance or illumination boundaries, and these all have the property that they are spatially. Because of this, the zero-crossing segments from the different channels are not independent, and rules are deduced for combining them into a description of the image. This description is called the raw primal sketch. The theory explains several basic psychophysical findings, and the operation of forming oriented zero-crossing segments from the output of centre-surround delta 2G filters acting on the image forms the basis for a physiological model of simple cells (see Marr & Ullman 1979).

  11. 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.

  12. 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.

  13. Conformal field theories from deformations of theories with Wn symmetry

    NASA Astrophysics Data System (ADS)

    Babaro, Juan Pablo; Giribet, Gaston; Ranjbar, Arash

    2016-10-01

    We construct a set of nonrational conformal field theories that consist of deformations of Toda field theory for s l (n ). In addition to preserving conformal invariance, the theories may still exhibit a remnant infinite-dimensional affine symmetry. The case n =3 is used to illustrate this phenomenon, together with further deformations that yield enhanced Kac-Moody symmetry algebras. For generic n we compute N -point correlation functions on the Riemann sphere and show that these can be expressed in terms of s l (n ) Toda field theory ((N -2 )n +2 ) -point correlation functions.

  14. Exploring gravitational theories beyond Horndeski

    SciTech Connect

    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.

  15. Exploring gravitational theories beyond Horndeski

    NASA Astrophysics Data System (ADS)

    Gleyzes, Jérôme; Langlois, David; Piazza, Federico; Vernizzi, Filippo

    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 G3. 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 G3 into Horndeski theories.

  16. Learning theory and intrapsychic conflict.

    PubMed

    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.

  17. 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.

  18. A succession of theories: purging redundancy from disturbance theory.

    PubMed

    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

  19. Selected topics in gauge theories

    SciTech Connect

    Beg, M.A.G.; Hernandez Galeana, A.

    1986-06-20

    Developments in gauge field theory in the past fourteen years are discussed. The canonical description of electroweak and strong interactions is described including the role played by QCD and QFD. The Salam-Weinberg theory of electroweak interactions is reviewed with emphasis on Higgs mass and renormalization group analysis. Implications of hyper-color theories are discussed. Composite models of quarks and leptons are considered including hyperfermions as part of a subquark multiplet. (AIP)

  20. Invariants from classical field theory

    SciTech Connect

    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.

  1. Hard amplitudes in gauge theories

    SciTech Connect

    Parke, S.J.

    1991-03-01

    In this lecture series 1 presents recent developments in perturbation theory methods for gauge theories for processes with many partons. These techniques and results are useful in the calculation of cross sections for processes with many final state partons which have applications in the study of multi-jet phenomena in high-energy colliders. The results illuminate many important and interesting properties of non-abelian gauge theories. 30 refs., 9 figs.

  2. A critique of Theory Z.

    PubMed

    Sullivan, J J

    1983-01-01

    Ouchi's Theory Z prescribes how employees should be motivated for increased productivity. Based on the theoretical work of Emile Durkheim, it views the modern large corporation as a communal alternative to the shortcomings of other institutions in industrial mass society. Ouchi's assertion that Japan is the industrial society in which Theory Z has flourished received limited support from research findings. Moreover, Ouchi's grounding of the theory in humanistic management seem unwarranted.

  3. Brain Physiology: Research and Theory.

    ERIC Educational Resources Information Center

    Esler, William K.

    1982-01-01

    Indicates how research about the physiology and chemistry of the brain verifies the educational applications of Piaget's theory. Discusses maturation, experience, social transmission, and equilibration. (Author/DC)

  4. New View of Relativity Theory

    NASA Astrophysics Data System (ADS)

    Martini, Luiz Cesar

    2014-04-01

    This article results from Introducing the Dimensional Continuous Space-Time Theory that was published in reference 1. The Dimensional Continuous Space-Time Theory shows a series of facts relative to matter, energy, space and concludes that empty space is inelastic, absolutely stationary, motionless, perpetual, without possibility of deformation neither can it be destroyed or created. A elementary cell of empty space or a certain amount of empty space can be occupied by any quantity of energy or matter without any alteration or deformation. As a consequence of these properties and being a integral part of the theory, the principles of Relativity Theory must be changed to become simple and intuitive.

  5. Nonstationary statistical theory for multipactor

    SciTech Connect

    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.

  6. Anatomy of a gauge theory

    SciTech Connect

    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.

  7. 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.

  8. Canonical density matrix perturbation theory.

    PubMed

    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

  9. 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.

  10. Toward a Unified Consciousness Theory

    ERIC Educational Resources Information Center

    Johnson, Richard H.

    1977-01-01

    The beginning of a holistic theory that can treat paranormal phenomena as normal human development is presented. Implications for counseling, counselor education, and counselor supervision are discussed. (Author)

  11. Canonical density matrix perturbation theory.

    PubMed

    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.

  12. 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.

  13. 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)

  14. 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,…

  15. 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…

  16. Particle Theory & Cosmology

    SciTech Connect

    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

  17. Double Exponential Relativity Theory Coupled Theoretically with Quantum Theory?

    SciTech Connect

    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.

  18. 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…

  19. Integrating Practice-to-Theory and Theory-to-Practice

    ERIC Educational Resources Information Center

    Johnson, R. Burke; Stefurak, Tres

    2012-01-01

    In "Towards a systemic theory of gifted education", Ziegler and Phillipson offer a useful critique of current research and the current paradigm in gifted education. They provide an interesting and useful merging of systems theory with their actiotope model, and using this paradigm they suggest many fruitful areas for future research. However, the…

  20. The Lorentz Theory of Electrons and Einstein's Theory of Relativity

    ERIC Educational Resources Information Center

    Goldberg, Stanley

    1969-01-01

    Traces the development of Lorentz's theory of electrons as applied to the problem of the electrodynamics of moving bodies. Presents evidence that the principle of relativity did not play an important role in Lorentz's theory, and that though Lorentz eventually acknowledged Einstein's work, he was unwilling to completely embrace the Einstein…

  1. 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…

  2. Introduction to conformal field theory and string theory

    SciTech Connect

    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.

  3. An Educational Theory Based on Game Theory. Preliminary Work.

    ERIC Educational Resources Information Center

    Chapman, Laura Hill

    Game theory may be a fruitful basis for educational theory. After describing games and related concepts like "utility," the author sets up examples of how games may be used as a basis for selecting teaching strategies. For instance, a teacher may decide to change many aspects of his teaching style, rather than just one at a time, if there is a…

  4. Theory of gaseous detonations.

    PubMed

    Clavin, Paul

    2004-09-01

    The objective of the present paper is to review some developments that have occurred in detonation theory over the last ten years. They concern nonlinear dynamics of detonation fronts, namely patterns of pulsating and/or cellular fronts, selection of the cell size, dynamical self-quenching, direct (blast) or spontaneous initiation, and transition from deflagration to detonation. These phenomena are all well documented by experiments since the sixties but remained unexplained until recently. In the first part of the paper, the patterns of cellular detonations are described by an asymptotic solution to nonlinear hyperbolic equations (reactive Euler equations) in the form of unsteady (sometime chaotic) and multidimensional traveling-waves. In the second part, turning points of quasi-steady solutions are shown to correspond to critical conditions of fully unsteady problems, either for (direct or spontaneous) initiation or for spontaneous failure (self-quenching). Physical insights are tentatively presented rather than technical aspects. The challenge is to identify the physical mechanisms with their relevant parameters, and more specifically to explain how the length-scales involved in detonation dynamics are larger by two order of magnitude (at least) than the length-scale involved in the steady planar traveling-wave solution (detonation thickness). PMID:15446993

  5. Paleoanthropology and evolutionary theory.

    PubMed

    Tattersall, Ian

    2012-01-01

    Paleoanthropologists of the first half of the twentieth century were little concerned either with evolutionary theory or with the technicalities and broader implications of zoological nomenclature. In consequence, the paleoanthropological literature of the period consisted largely of a series of descriptions accompanied by authoritative pronouncements, together with a huge excess of hominid genera and species. Given the intellectual flimsiness of the resulting paleoanthropological framework, it is hardly surprising that in 1950 the ornithologist Ernst Mayr met little resistance when he urged the new postwar generation of paleoanthropologists to accept not only the elegant reductionism of the Evolutionary Synthesis but a vast oversimplification of hominid phylogenetic history and nomenclature. Indeed, the impact of Mayr's onslaught was so great that even when developments in evolutionary biology during the last quarter of the century brought other paleontologists to the realization that much more has been involved in evolutionary histories than the simple action of natural selection within gradually transforming lineages, paleoanthropologists proved highly reluctant to follow. Even today, paleoanthropologists are struggling to reconcile an intuitive realization that the burgeoning hominid fossil record harbors a substantial diversity of species (bringing hominid evolutionary patterns into line with that of other successful mammalian families), with the desire to cram a huge variety of morphologies into an unrealistically minimalist systematic framework. As long as this theoretical ambivalence persists, our perception of events in hominid phylogeny will continue to be distorted.

  6. Chain entanglements. I. Theory

    NASA Astrophysics Data System (ADS)

    Fixman, Marshall

    1988-09-01

    A model of concentrated polymer solution dynamics is described. The forces in a linear generalized Langevin equation for the motion of a probe chain are derived on the assumption that all relaxation of the forces is due to motion of the surrounding matrix. Vicinal chain displacements are classified as viscoelastic deformation, reptation, and minor residual fluctuations. The latter provide a torsional relaxation of the primitive path that minimizes the significance of transverse forces on the probe chain. All displacements of vicinal segments are assumed proportional to the forces that they exert on the probe chain. In response to an external force, the displacement of the probe chain relative to a laboratory frame is increased by viscoelastic deformation of the matrix, but reptative diffusion relative to the deforming matrix is slowed down. The net effect on translational diffusion is negligible if the probe and vicinal chains have the same chain length N, but the friction constant for reptative motion is increased by a factor N1-xs. xs=1/2 if Gaussian conformational statistics applies during the disengagement process, while xs =0.6 if excluded volume statistics applies. The translational friction constant is βp ˜N2, as in reptation theory, but the viscosity is η˜N4-xs . The persistence of entanglements during the translational diffusion of the probe chain across many radii of gyration is rationalized pictorially in terms of correlated reptative motion of the probe and vicinal chains.

  7. The theory of sunspots

    NASA Technical Reports Server (NTRS)

    Thomas, John H.; Weiss, Nigel O.

    1992-01-01

    This review covers the present state of our theoretical understanding of the physics of sunspots, along with the principal observational results that need to be explained. The topics covered range from the detailed structure of an individual sunspot to the broad connection between sunspots and the global solar magnetic field and the solar cycle. Our aim is to give a critical discussion of the theoretical ideas and models without presenting mathematical details. After outlining the historical development of the basic concepts associated with the magnetohydrodynamic theory of sunspots, we discuss recent treatments of their properties and structure, placing special emphasis on developments that have occurred within the last ten years. There have been remarkable improvements in the theoretical modelling of sunspots, led by new ideas and by more elaborate and realistic numerical simulations. At the same time, new observations have raised new theoretical questions or caused old ones to be reconsidered. In particular, measurements of oscillations in and around sunspots have opened up the new field of sunspot seismology, while recent high-resolution observations have forced us to rethink the structure of a sunspot penumbra.

  8. Microlesions - Theory and reality

    NASA Technical Reports Server (NTRS)

    Worgul, Basil V.; Koniarek, Jan P.; Krebs, Wolf

    1989-01-01

    Efforts to assess radiation risk in space have been complicated by the considerable unknowns regarding the biological effects of the heavy ion component (HZE particles) of the cosmic rays. The attention has focused primarily on the assignation of a quality factor (Q) which would take into account the greater effectiveness of heavy ions vis-a-vis other forms of ionizing radiation. If, however, as the so-called 'microlesion theory' allows, the passage of HZE particles through living tissue produces unique biological damage, the traditional use of Q becomes meaningless. Therefore, it is critical to determine if microlesions, in fact, do exist. While the concept does not necessarily require detectable morphological damage, 'tunnel-lesions' or holes in ocular tissues have been cited as evidence of microlesions. These data, however, are open to reinterpretation. Ongoing light, scanning and transmission electron microscopic studies of the corneas, lenses and retinas of rat eyes exposed to 450 MeV/amu Fe-56 ions thus far have not revealed tunnel-lesion damage. The morphological effects of the heavy ions have been found to be qualitatively similar to the changes following other kinds of ionizing radiation.

  9. Theory of gaseous detonations.

    PubMed

    Clavin, Paul

    2004-09-01

    The objective of the present paper is to review some developments that have occurred in detonation theory over the last ten years. They concern nonlinear dynamics of detonation fronts, namely patterns of pulsating and/or cellular fronts, selection of the cell size, dynamical self-quenching, direct (blast) or spontaneous initiation, and transition from deflagration to detonation. These phenomena are all well documented by experiments since the sixties but remained unexplained until recently. In the first part of the paper, the patterns of cellular detonations are described by an asymptotic solution to nonlinear hyperbolic equations (reactive Euler equations) in the form of unsteady (sometime chaotic) and multidimensional traveling-waves. In the second part, turning points of quasi-steady solutions are shown to correspond to critical conditions of fully unsteady problems, either for (direct or spontaneous) initiation or for spontaneous failure (self-quenching). Physical insights are tentatively presented rather than technical aspects. The challenge is to identify the physical mechanisms with their relevant parameters, and more specifically to explain how the length-scales involved in detonation dynamics are larger by two order of magnitude (at least) than the length-scale involved in the steady planar traveling-wave solution (detonation thickness).

  10. [Chronotherapy and relativity theory].

    PubMed

    Polishchuk, N A

    2008-01-01

    The course of time itself in alive organisms is treated from positions of the special theory of the relativity created by A. Einstein in 1905 and added by the Nobel winners H.A.Lorentsem, M. Plankom, M. fon Laue. These achievements of fundamental physics have been put in a basis of special medical technology "Resonant chronophytotherapy" (SMT RCPT) which is applied in practice of treatment of chronic diseases for 27 years. Grass tinctures in various dosages are used in SMT RCPT, which patients take once a day during precisely designated time. Parameters "dosage-time" daily vary. SMT RCPT have been conducted in treatment of epilepsy bronchial asthma, rheumatism, sclerodermia, hypertension, chronic glomerulonephritis, vegeto-vascular dystonia, female sterility, circular alopecia, vitiligo, eczema, psoriasis, onychomycosis. SMT RCPT does have adverse events, has no contra-indications to its use, directed, first of all, on elimination of nonspecific signs of a disease, reduces dependence and complications of the use of chemical synthetic preparations. SMT RCPT can be combined with any kind of specific treatment. Internet-variant of SMT RCPT has been developed. Chronomedicine is priority tendency in industrialized countries of the world--the USA, the Great Britain, Germany, France, Russia, China, Japan and appears on lead positions among alternative methods of treatment, both traditional, and non-traditional. PMID:19145832

  11. New Pulsar Theory

    NASA Astrophysics Data System (ADS)

    Kebede, Legesse

    2015-08-01

    Standard pulsar theory is based on fields that are conserved from progenitor stars. This has limited the scope of pulsar astronomy to a kind of study very much confined to a limited type of pulsars, so called field pulsars. The large majority of pulsars are technically eliminated from statistical studies because they are either too massive, or are of very high magnetic field with no mechanism yet known which forces them to decay to very low frequency rotators in a matter of a few thousands of years. This is one distinct property of these highly magnetized pulsars. The current presentation focuses on a new source for the generation of pulsar fields namely spinning separated surface charges and it shows that pulsar fields are strictly mass dependent. Massive neutron stars are strongly magnetized ( ≥ 1018 G) and less massive ones are weakly magnetized (1011 - 1013 G). This work therefore dismisses the current belief that there have to be two classes of pulsars (field pulsars and anomalous pulsars). It leads to a decay law that provides results that are consistent with observations from these two so called distinct classes of pulsars. This work also suggests that pulsar fields should be infinitely multi-polar which helps to successfully addresses the longtime issues of pulse shape and promises that the current problem of pulsar radiation could be solvable..

  12. [Chronotherapy and relativity theory].

    PubMed

    Polishchuk, N A

    2008-01-01

    The course of time itself in alive organisms is treated from positions of the special theory of the relativity created by A. Einstein in 1905 and added by the Nobel winners H.A.Lorentsem, M. Plankom, M. fon Laue. These achievements of fundamental physics have been put in a basis of special medical technology "Resonant chronophytotherapy" (SMT RCPT) which is applied in practice of treatment of chronic diseases for 27 years. Grass tinctures in various dosages are used in SMT RCPT, which patients take once a day during precisely designated time. Parameters "dosage-time" daily vary. SMT RCPT have been conducted in treatment of epilepsy bronchial asthma, rheumatism, sclerodermia, hypertension, chronic glomerulonephritis, vegeto-vascular dystonia, female sterility, circular alopecia, vitiligo, eczema, psoriasis, onychomycosis. SMT RCPT does have adverse events, has no contra-indications to its use, directed, first of all, on elimination of nonspecific signs of a disease, reduces dependence and complications of the use of chemical synthetic preparations. SMT RCPT can be combined with any kind of specific treatment. Internet-variant of SMT RCPT has been developed. Chronomedicine is priority tendency in industrialized countries of the world--the USA, the Great Britain, Germany, France, Russia, China, Japan and appears on lead positions among alternative methods of treatment, both traditional, and non-traditional.

  13. Normative population theory.

    PubMed

    Cowen, T

    1989-01-01

    This article finds utilitarian and contractarian approaches to solving the problem of optimal population unacceptable. The principles of utility refer to the best population as the one which contains the greatest sum of utility or the one with the highest average utility. Yet Parfits's repugnant conclusion states that these can imply a very large population at a very low standard of living. Cowen's Methuselah's Paradox says that for any possible happy and meaningful life, we can imagine another, much longer life which demonstrates the absurdity of the utility principles. Lewis argues for a conception of well being based upon choices over whole irreducible states of affairs, i.e., an ordinal concept of value. The contractarian approach assumes that we would rationally choose what type of life we were to live if the choice were made without anyone knowing his particular standing in the world--the veil of ignorance. This requires the individuals to choose on the basis of self interest, but gives too much weight to the individuals actually being born. The most promising population theory appears to be the ideal participant method. Simply stated the optimal population is what an individual would prefer if he had to sequentially live out each life in his choice. Further, this method may be able to reduce the difficulties with evaluating alternate populations to the common problem of aggregating disparate preferences.

  14. General theory of evolution.

    PubMed

    Csányi, V

    1980-01-01

    The biological, neural, cultural and technical evolutions and their phenomena have been explored, and on the basis of our findings the formation of a general theory of evolution has been undertaken. In each of the systems studied, the presence of structural building units, excitable structures and an energy-flow going through the system can be observed. Under the organizing effect of this energy-flow, the spontaneous generation of the replicative information begins and the structures of the system establish functional relations with each other. It can be demonstrated that the evolution of structures has a replicative character. The evolution goes through a phase of non-identical replication, and reaches the phase of identical replication. The parts of the system become separated, that is, compartments develop within it. The replicative information becomes compartmentalized and it converges. As a consequence of the convergence, the compartments compose new structural units which is tantamount to the development of new evolutional levels. The direction of evolution is determined by the growth of replicative information, and this process is concluded when the total system becomes one replicative unit. In the last part of the paper a few of the basic principles of evolution concerning matter, energy and information are drawn up.

  15. Modeling and flow theory

    SciTech Connect

    Not Available

    1981-10-01

    (1) We recommend the establishment of an experimental test facility, appropriately instrumented, dedicated to research on theoretical modeling concepts. Validation of models for the various flow regimes, and establishment of the limitations or concepts used in the construction of models, are sorely needed areas of research. There exists no mechanism currently for funding of such research on a systematic basis. Such a facility would provide information fundamental to progress in the physics of turbulent multi-phase flow, which would also have impact on the understanding of coal utilization processes; (2) combustion research appears to have special institutional barriers to information exchange because it is an established, commercial ongoing effort, with heavy reliance on empirical data for proprietary configurations; (3) for both gasification and combustion reactors, current models appear to handle adequately some, perhaps even most, gross aspects of the reactors such as overall efficiency and major chemical output constituents. However, new and more stringent requirements concerning NOX, SOX and POX (small paticulate) production require greater understanding of process details and spatial inhomogenities, hence refinement of current models to include some greater detail is necessary; (4) further progress in the theory of single-phase turbulent flow would benefit our understanding of both combustors and gasifiers; and (5) another area in which theoretical development would be extremely useful is multi-phase flow.

  16. Superstatistics: Theory and Applications

    NASA Astrophysics Data System (ADS)

    Beck, C.

    2015-12-01

    Many driven nonequilibrium systems are described by a superposition of several dynamics on various time scales. If time scales are clearly separated then the formalism of superstatistics can be applied, leading effectively to a more general statistical mechanics relevant for complex systems. In these types of systems there is often dynamical behavior that is characterized by spatio-temporal fluctuations of an intensive parameter β. This parameter may be for example the inverse temperature, or an effective friction constant, or the amplitude of Gaussian white noise, or the energy dissipation in turbulent flows, or simply a local variance parameter extracted from a measured signal. A nonhomogenoeus spatially extended system with fluctuations in β on a large time scale, larger than the local relaxation time, leads to a superstatistical description, by averaging local Boltzmann factors using a suitable weight function f(β). Kappa distributions in space plasma physics are one example which naturally follows out of this formalism, but there are many applications in other areas as well. In this talk I will sketch the basic theory underlying the superstatistical approach and then describe a couple of recent applications.

  17. Toroidal spiral field theory.

    NASA Astrophysics Data System (ADS)

    Ginzburg, V. B.

    1996-09-01

    A toroidal spiral field is introduced that propagates around all the objects in the universe. The nature of this field can be either gravitational or electrostatic or magnetic, and it governs the motion of the objects as well as the forces that act upon them. The topology of the toroidal spiral field is obtained when the Bertrami vortex comprised of two helical fluxes of opposite vorticity is curved into a circle. The main parameter that defines the geometry of the toroidal spiral field is the inversion radius of a sphere at which the toroidal fluxes of opposite vorticity meet. The inversion sphere is the border surface at which the matter converts into anti-matter, and at which the law of physics are inverted. The theory covers the problem of two objects orbiting each other with possible sizes ranging from an elementary particle to a black hole and to a galaxy. The equations obtained define the radii of the stationary quantum orbits which can be applied to a structure of the hydrogen atom, including its nucleus, as well as to a structure of a planetary system and a black hole. They also establish the relativistic relationships for the gravitational and inertial masses as well as for the electrical charge which are quite different than those proposed by Lorentz.

  18. THEORY IN RELIGION AND AGING: AN OVERVIEW

    PubMed Central

    Levin, Jeff; Chatters, Linda M.; Taylor, Robert Joseph

    2011-01-01

    This paper provides an overview of theory in religion, aging, and health. It offers both a primer on theory and a roadmap for researchers. Four “tenses” of theory are described—distinct ways that theory comes into play in this field: grand theory, mid-range theory, use of theoretical models, and positing of constructs which mediate or moderate putative religious effects. Examples are given of both explicit and implicit uses of theory. Sources of theory for this field are then identified, emphasizing perspectives of sociologists and psychologists, and discussion is given to limitations of theory. Finally, reflections are offered as to why theory matters. PMID:20087662

  19. Implicit Theories of Peer Relationships

    ERIC Educational Resources Information Center

    Rudolph, Karen D.

    2010-01-01

    This research investigated the role of children's implicit theories of peer relationships in their psychological, emotional, and behavioral adjustment. Participants included 206 children (110 girls; 96 boys; M age = 10.13 years, SD = 1.16) who reported on their implicit theories of peer relationships, social goal orientation, need for approval,…

  20. Critical Social Theory: A Portrait

    ERIC Educational Resources Information Center

    Torres, Carlos A.

    2012-01-01

    The term Critical Social Theory is employed in this article following the tradition of the Frankfurt School, and particularly the work of Herbert Marcuse and his interpretation of the political and social philosophy of Hegel and Marx. Discussing the contribution of G.W.F. Hegel to social theory Marcuse argued that: "Hegel's system brings to a…