The Universal One-Loop Effective Action
Drozd, Aleksandra; Quevillon, Jérémie; You, Tevong
2016-01-01
We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.
One-loop effective action in quantum gravitation
DEFF Research Database (Denmark)
Rachwal, Leslaw; Codello, Alessandro; Percacci, Roberto
2016-01-01
We present the formalism of computing one-loop effective action for Quantum Gravitation using non-local heat kernel methods. We found agreement with previous old results. In main part of my presentation I considered the system of E-H gravitation and scalar fields. We were able to derive non......-local quantum effective action up to the second order in heat kernel generalized curvatures. By going to flat spacetime expressions for gravitational form factors are possible to construct and compare with the results from effective field theory for gravity....
One-loop effective action for Einstein gravity in special background gauge
Lavrov, P M; Lavrov, P M; Reshetnyak, A A
1995-01-01
The one-loop effective action for Einstein gravity in a special one-parameter background gauge is calculated up to first order in a gauge parameter. It is shown that the effective action does not depend upon the gauge parameter on shell.
Anatomy of One-Loop Effective Action in Noncommutative Scalar Field Theories
Kiem, Youngjai; Sato, Haru-Tada; Yee, Jung-Tay; Kiem, Youngjai; Rey, Soo-Jong; Sato, Haru-Tada; Yee, Jung-Tay
2002-01-01
One-loop effective action of noncommutative scalar field theory with cubic self-interaction is studied. Utilizing worldline formulation, both planar and nonplanar part of the effective action are computed explicitly. We find complete agreement of the result with Seiberg-Witten limit of string worldsheet computation and standard Feynman diagrammatics. We prove that, at low-energy and large noncommutativity limit, nonplanar part of the effective action is simplified enormously and is resummable into a quadratic action of scalar open Wilson line operators.
Mixed Heavy-Light Matching in the Universal One-Loop Effective Action
Ellis, Sebastian A R; You, Tevong; Zhang, Zhengkang
2016-01-01
Recently, a general result for evaluating the path integral at one loop was obtained in the form of the Universal One-Loop Effective Action. It may be used to derive effective field theory operators of dimensions up to six, by evaluating the traces of matrices in this expression, with the mass-dependence encapsulated in the universal coefficients. Here we show that it can account for loops of mixed heavy-light particles in the matching procedure. Our prescription for computing these mixed contributions to the Wilson coefficients is conceptually simple. Moreover it has the advantage of maintaining the universal structure of the effective action, which we illustrate using the example of integrating out a heavy electroweak triplet scalar coupling to a light Higgs doublet. Finally we also identify new structures that were previously neglected in the universal results.
In-Out Formalism for One-Loop Effective Actions in QED and Gravity
Kim, Sang Pyo
2016-01-01
The in-out formalism is a systematic and powerful method for finding the effective actions in an electromagnetic field and a curved spacetime provided that the field equation has explicitly known solutions. The effective action becomes complex when pairs of charged particles are produced due to an electric field and curved spacetime. This may lead to a conjecture of one-to-one correspondence between the vacuum polarization (real part) and the vacuum persistence (imaginary part). We illustrate the one-loop effective action in a constant electric field in a Minkowski spacetime and in a uniform electric field in a two-dimensional (anti-) de sitter space.
Partially Massless Higher-Spin Theory II: One-Loop Effective Actions
Brust, Christopher
2016-01-01
We continue our study of a generalization of the D-dimensional linearized Vasiliev higher-spin equations to include a tower of partially massless (PM) fields. We compute one-loop effective actions by evaluating zeta functions for both the "minimal" and "non-minimal" parity-even versions of the theory. Specifically, we compute the log-divergent part of the effective action in odd-dimensional Euclidean AdS spaces for D=7 through 19 (dual to the $a$-type conformal anomaly of the dual boundary theory), and the finite part of the effective action in even-dimensional Euclidean AdS spaces for D=4 through 8 (dual to the free energy on a sphere of the dual boundary theory). We pay special attention to the case D=4, where module mixings occur in the dual field theory and subtlety arises in the one-loop computation. The results provide evidence that the theory is UV complete and one-loop exact, and we conjecture and provide evidence for a map between the inverse Newton's constant of the partially massless higher-spin th...
Extending the Universal One-Loop Effective Action: heavy-light coefficients
Ellis, Sebastian A. R.; Quevillon, Jérémie; You, Tevong; Zhang, Zhengkang
2017-08-01
The Universal One-Loop Effective Action (UOLEA) is a general expression for the effective action obtained by evaluating in a model-independent way the one-loop expansion of a functional path integral. It can be used to match UV theories to their low-energy EFTs more efficiently by avoiding redundant steps in the application of functional methods, simplifying the process of obtaining Wilson coefficients of operators up to dimension six. In addition to loops involving only heavy fields, matching may require the inclusion of loops containing both heavy and light particles. Here we use the recently-developed covariant diagram technique to extend the UOLEA to include heavy-light terms which retain the same universal structure as the previously-derived heavy-only terms. As an example of its application, we integrate out a heavy singlet scalar with a linear coupling to a light doublet Higgs. The extension presented here is a first step towards completing the UOLEA to incorporate all possible structures encountered in a covariant derivative expansion of the one-loop path integral.
One-loop effective action of QCD at high temperature using the heat kernel method
Energy Technology Data Exchange (ETDEWEB)
Megias, E. [Universidad de Granada (Spain). Dept. de Fisica Moderna]. E-mail: emegias@ugr.es
2004-07-01
Perturbation theory is an important tool to describe the properties of QCD at very high temperatures. Recently a new technique has been proposed to compute the one-loop effective action of QCD at finite temperature by making a gauge covariant derivative expansion, which is fully consistent with topologically small and large gauge transformations (also time dependent transformations). This technique is based on the heat kernel expansion, and the thermal Wilson line plays an essential role. We consider a general SU(N-c) gauge group. (author)
One-loop effective actions and 2D hydrodynamics with anomalies
Directory of Open Access Journals (Sweden)
Gim Seng Ng
2015-06-01
Full Text Available We revisit the study of a 2D quantum field theory in the hydrodynamic regime and develop a formalism based on Euclidean one-loop partition functions that is suitable to analyze transport properties due to gauge and gravitational anomalies. To do so, we generalize the method of a modified Dirac operator developed for zero-temperature anomalies to finite temperature, chemical potentials and rotations.
One-loop and D-instanton corrections to the effective action of open string models
Energy Technology Data Exchange (ETDEWEB)
Schmidt-Sommerfeld, Maximilian
2009-07-02
Methods for the calculation of certain corrections to effective actions, which comprehend the low-energy physics of string compactifications with open strings, are explained. First the shape of such actions is describes and some examples for compactifications are presented, especially a type I string model to which a dual model on the base of the heterotic string is known. Then corrections on the gauge coupling constant and on the gauge-kinetic function are discussed. general procedures for their calculation are sketched and applied to some models. The explicitly determinded corrections depend non-holomorphically on the moduli of the compactification manifold. It is explained that this is not in disagreement on the holomorphy of the gauge-kinetic function and how the latter can be extracted from the calculated results. Next D-instantons and their influence on the low-energy action are detailedly analyzed, whereby the zero modes of the instantons and global Abelian symmetries play a central role. A formula for the caclulation of scattering matrix elements in instanton sectors is given. It is to be expected that the considered instantons contribute to the superpotential of the low-energy action. However from the formula it becomes not immediately clear, how far this is possible. The mentioned formula seems to lead to expressions, which are in disagreement to the holomorphy of the superpotential. It is shown that non-holomorphic terms partly simplify, partly are so composed that the result is in accordance with the holomorphy of the superpotential. The D-instanton calculus is then used in order to derive the ADS superpotential, which is known from field theory. That this is possible is to be considered as successful test of the instanton calculus. D-instanton corrections to the gauge-kinetic functions are considered. S duality between the type I and the heterotic string is used in order to determine how the structure of the zero modes of the relevant instantons looks
One-loop effective lagrangians after matching
Energy Technology Data Exchange (ETDEWEB)
Aguila, F. del; Santiago, J. [Universidad de Granada, Departamento de Fisica Teorica y del Cosmos and CAFPE, Granada (Spain); Kunszt, Z. [ETH Zuerich, Institute for Theoretical Physics, Zuerich (Switzerland)
2016-05-15
We discuss the limitations of the covariant derivative expansion prescription advocated to compute the one-loop Standard Model (SM) effective lagrangian when the heavy fields couple linearly to the SM. In particular, one-loop contributions resulting from the exchange of both heavy and light fields must be explicitly taken into account through matching because the proposed functional approach alone does not account for them. We review a simple case with a heavy scalar singlet of charge -1 to illustrate the argument. As two other examples where this matching is needed and this functional method gives a vanishing result, up to renormalization of the heavy sector parameters, we re-evaluate the one-loop corrections to the T-parameter due to a heavy scalar triplet with vanishing hypercharge coupling to the Brout-Englert-Higgs boson and to a heavy vector-like quark singlet of charged 2/3 mixing with the top quark, respectively. In all cases we make use of a new code for matching fundamental and effective theories in models with arbitrary heavy field additions. (orig.)
Secular effects on inflation from one-loop quantum gravity
Cabrer, J. A.; Espriu, D.
2008-06-01
In this Letter we revisit and extend a previous analysis where the possible relevance of quantum gravity effects in a cosmological setup was studied. The object of interest are non-local (logarithmic) terms generated in the effective action of gravity due to the exchange in loops of massless modes (such as photons or the gravitons themselves). We correct one mistake existing in the previous work and discuss the issue in a more general setting in different cosmological scenarios. We obtain the one-loop quantum-corrected evolution equations for the cosmological scale factor up to a given order in a derivative expansion in two particular cases: a matter dominated universe with vanishing cosmological constant, and in a de Sitter universe. We show that the quantum corrections, albeit tiny, may have a secular effect that eventually modifies the expansion rate. For a de Sitter universe they tend to slow down the rate of the expansion, while the effect may be the opposite in a matter dominated universe.
One-loop Correction of the Tachyon Action in Boundary Superstring Field Theory
Alishahiha, M.
2001-01-01
We compute one-loop correction to the string field theory. We would expect that the one-loop correction comes from the partition function of the two-dimensional worldsheet theory on the annulus. The annulus correction suggests that the genus expansion is, somehow, governed by the effective string co
One-loop potential with scale invariance and effective operators
Ghilencea, D M
2016-01-01
We study quantum corrections to the scalar potential in classically scale invariant theories, using a manifestly scale invariant regularization. To this purpose, the subtraction scale $\\mu$ of the dimensional regularization is generated after spontaneous scale symmetry breaking, from a subtraction function of the fields, $\\mu(\\phi,\\sigma)$. This function is then uniquely determined from general principles showing that it depends on the dilaton only, with $\\mu(\\sigma)\\sim \\sigma$. The result is a scale invariant one-loop potential $U$ for a higgs field $\\phi$ and dilaton $\\sigma$ that contains an additional {\\it finite} quantum correction $\\Delta U(\\phi,\\sigma)$, beyond the Coleman Weinberg term. $\\Delta U$ contains new, non-polynomial effective operators like $\\phi^6/\\sigma^2$ whose quantum origin is explained. A flat direction is maintained at the quantum level, the model has vanishing vacuum energy and the one-loop correction to the mass of $\\phi$ remains small without tuning (of its self-coupling, etc) bey...
2D quantum gravity at one loop with Liouville and Mabuchi actions
Energy Technology Data Exchange (ETDEWEB)
Bilal, Adel, E-mail: adel.bilal@lpt.ens.fr [Centre National de la Recherche Scientifique, Laboratoire de Physique Théorique de l' École Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Ferrari, Frank, E-mail: frank.ferrari@ulb.ac.be [Service de Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus de la Plaine, CP 231, B-1050 Bruxelles (Belgium); Klevtsov, Semyon, E-mail: klevtsov@math.uni-koeln.de [Mathematisches Institut and Institut für Theoretische Physik, Universität zu Köln, Weyertal 86-90, 50931 Köln (Germany)
2014-03-15
We study a new two-dimensional quantum gravity theory, based on a gravitational action containing both the familiar Liouville term and the Mabuchi functional, which has been shown to be related to the coupling of non-conformal matter to gravity. We compute the one-loop string susceptibility from a first-principle, path integral approach in the Kähler parameterization of the metrics and discuss the particularities that arise in the case of the pure Mabuchi theory. While we mainly use the most convenient spectral cutoff regularization to perform our calculations, we also discuss the interesting subtleties associated with the multiplicative anomaly in the familiar ζ-function scheme, which turns out to have a genuine physical effect for our calculations. In particular, we derive and use a general multiplicative anomaly formula for Laplace-type operators on arbitrary compact Riemann surfaces.
The one loop renormalization of the effective Higgs sector and its implications
Yan Qi Shu; Yan, Qi-Shu; Du, Dong-Sheng
2002-01-01
We study the one-loop renormalization the standard model with anomalous Higgs couplings ($O(p^2)$) by using the background field method, and provide the whole divergence structure at one loop level. The one-loop divergence structure indicates that, under the quantum corrections, only after taking into account the mass terms of Z bosons ($O(p^2)$) and the whole bosonic sector of the electroweak chiral Lagrangian ($O(p^4)$), can the effective Lagrangian be complete up to $O(p^4)$.
On the one-loop effective potential in nonlocal supersymmetric theories
de Mello, E R Bezerra; Nascimento, J R; Petrov, A Yu
2016-01-01
Within the superfield approach, we consider the nonlocal generalization of the Wess-Zumino model and calculate the one-loop low-energy contributions to the effective action. Four different nonlocal models are considered, among which only the first model does not reduce to the standard Wess-Zumino model when we take the parameter of nonlocality of the model, $\\Lambda$, much greater than any energy scale; in addition, this model also depends on an extra parameter, $\\xi$. As to the other three models, the result looks like the renormalized effective potential for the usual Wess-Zumino model, where the normalization scale $\\mu$ is replaced by the $\\Lambda$. Moreover, the fourth model displays a divergence which can be eliminated through the appropriate wave function renormalization.
All one-loop scalar vertices in the effective potential approach
Camargo-Molina, José Eliel; Morais, António P.; Pasechnik, Roman; Sampaio, Marco O. P.; Wessén, Jonas
2016-08-01
Using the one-loop Coleman-Weinberg effective potential, we derive a general analytic expression for all the derivatives of the effective potential with respect to any number of classical scalar fields. The result is valid for a renormalisable theory in four dimensions with any number of scalars, fermions or gauge bosons. This result corresponds to the zero-external momentum contribution to a general one-loop diagram with N scalar external legs. We illustrate the use of the general result in two simple scalar singlet extensions of the Standard Model, to obtain the dominant contributions to the triple couplings of light scalar particles under the zero external momentum approximation.
All one-loop scalar vertices in the effective potential approach
Camargo-Molina, José Eliel; Pasechnik, Roman; Sampaio, Marco O P; Wessén, Jonas
2016-01-01
Using the one-loop Coleman-Weinberg effective potential, we derive a general analytic expression for all the derivatives of the effective potential with respect to any number of classical scalar fields. The result is valid for a renormalisable theory in four dimensions with any number of scalars, fermions or gauge bosons. This result corresponds to the zero-external momentum contribution to a general one-loop diagram with N scalar external legs. We illustrate the use of the general result in two simple scalar singlet extensions of the Standard Model, to obtain the dominant contributions to the triple couplings of light scalar particles under the zero external momentum approximation
Higgs Decay to Two Photons at One Loop in the Standard Model Effective Field Theory.
Hartmann, Christine; Trott, Michael
2015-11-06
We present the calculation of the CP conserving contributions to Γ(h→γγ), from dimension six operators at one-loop order, in the linear standard model effective field theory. We discuss the impact of these corrections on interpreting current and future experimental bounds on this decay.
One-loop effects of extra dimensions on the WWγ and WWZ vertices
Flores-Tlalpa, A.; Montaño, J.; Novales-Sánchez, H.; Ramírez-Zavaleta, F.; Toscano, J. J.
2011-01-01
The one-loop contribution of the excited Kaluza-Klein (KK) modes of the SUL(2) gauge group on the off-shell W-W+γ and W-W+Z vertices is calculated in the context of a pure Yang-Mills theory in five dimensions and its phenomenological implications discussed. The use of a gauge-fixing procedure for the excited KK modes that is covariant under the standard gauge transformations of the SUL(2) group is stressed. A gauge-fixing term and the Faddeev-Popov ghost sector for the KK gauge modes that are separately invariant under the standard gauge transformations of SUL(2) are presented. It is shown that the one-loop contributions of the KK modes to the off-shell W-W+γ and W-W+Z vertices are free of ultraviolet divergences and well-behaved at high energies. It is found that for a size of the fifth dimension of R-1˜1TeV, the one-loop contribution of the KK modes to these vertices is about 1 order of magnitude lower than the corresponding standard model radiative correction. This contribution is similar to the one estimated for new gauge bosons contributions in other contexts. Tree-level effects on these vertices induced by operators of higher canonical dimension are also investigated. It is found that these effects are lower than those generated at the one-loop order by the KK gauge modes.
The One-Loop Effective K\\"ahler Potential. I: Chiral Multiplets
Flauger, Raphael; Schmidt-Colinet, Cornelius; Sudano, Matthew
2012-01-01
We derive a universal formula for the one-loop renormalization of the effective K\\"ahler potential that applies to general supersymmetric effective field theories of chiral multiplets, with arbitrary interactions respecting N=1 supersymmetry in four dimensions. The resulting expression depends only on the tree-level mass spectrum and the form of the regulator. This formula simplifies and generalizes existing results in the literature. We include two examples to illustrate its use.
New physics effects in the Higgs trilinear self-coupling through one-loop radiative corrections
Moyotl, A; Castilla-Valdez, H; Pérez, M A
2016-01-01
We compute the one-loop corrections to the triple Higgs self-interaction $hhh$ in the framework of the Standard Model (SM), the Two Higgs Doublet Model type III (THDM-III) and the Littlest Higgs Model with T parity (LHBM+T). Our results are compared with previous results for the SM. In particular, we find that an imaginary part for the $\\lambda_{hhh}$ form factor is induced when one of the Higgs boson legs is off-mass shell with 4-momentum magnitude higher than the Higgs boson mass. This contribution is sensitive to virtual effects of the Higgs self-interaction, that induces a radiative correction to the $hhh$ coupling of order 11%. However, the radiative corrections associated to the new degrees of freedom of the THDM-III and the LHBM+T are rather smaller and comparable to the $W^\\pm$ and $Z^0$ gauge bosons one-loop corrections.
One-loop effective potential of the Higgs field on the Schwarzschild background
Kazinski, P. O.
2009-12-01
A one-loop effective potential of the Higgs field on the Schwarzschild background is derived in the framework of a toy model: a SO(N) scalar multiplet interacting with the gauge fields, the SO(N) gauge symmetry being broken by the Higgs mechanism. As expected, the potential depends on the space point and results in a mass shift of all massive particles near a black hole. It is shown that the obtained potential is generally covariant, depends on the space point through the metric component g00 in the adapted coordinates, and has the same form for an arbitrary static, spherically symmetric background. Some properties of this potential are investigated. In particular, if the conformal symmetry holds valid for massless particles on the given background, there exist only two possible scenarios depending on the sign of an arbitrary constant arising from the regularization procedure: the masses of all massive particles grow infinitely, when they approach the black hole horizon, or the gauge symmetry is restored at a finite distance from the horizon and all particles become massless. If the conformal symmetry is spoiled, an additional term in the effective potential appears and the intermediate regime arises. Several normalization conditions fixing the undefined constants are proposed, and estimations for the mass shifts are given in these cases. It should be mentioned that the use of the one-loop approximation becomes questionable in the region where the one-loop effective potential acquires large values. So, in that region, we can believe in the obtained results only to a certain extent.
Effective Field Theory of Integrating out Sfermions in the MSSM: Complete One-Loop Analysis
Huo, Ran
2015-01-01
We apply the covariant derivative expansion of the Coleman-Weinberg potential to the sfermion sector in the minimal supersymmetric standard model, matching it to the relevant dimension-6 operators in the standard model effective field theory at one-loop level. Emphasis is paid to nondegenerate large soft supersymmetry breaking mass squares, and the most general analytical Wilson coefficients are obtained for all pure bosonic dimension-6 operators. In addition to the non-logarithmic contributions, they generally have another logarithmic contributions. Various numerical results are shown, in particular the constraints in the large $X_t$ branch reproducing the $125$~GeV Higgs mass can be pushed to high values to almost completely probe the low stop mass region at the future FCC-ee experiment, even given the Higgs mass calculation uncertainty.
One-loop effective potential of the Higgs field on the Schwarzschild background
Kazinski, P O
2009-01-01
A one-loop effective potential of the Higgs field on the Schwarzschild background is derived in the framework of a toy model: a SO(N) scalar multiplet interacting with the gauge fields, the SO(N) gauge symmetry being broken by the Higgs mechanism. As expected, the potential depends on the space point and results in a mass shift of all massive particles near a black hole. Some properties of this potential are investigated. In particular, it turns out that there exist only two possible scenarios depending on a sign of an arbitrary constant arising from the regularization procedure: the masses of all massive particles grow infinitely when they approach the black hole horizon, or the gauge symmetry is restored at a finite distance from the horizon and all particles become massless. Several normalization conditions fixing the undefined constants are proposed, and estimations for the mass shifts are given in these cases.
One-loop effects of extra dimensions on the WW\\gamma and WWZ vertices
Flores-Tlalpa, A; Novales-Sánchez, H; Ramirez-Zavaleta, F; Toscano, J J
2010-01-01
The one-loop contribution of the excited Kaluza-Klein (KK) modes of the $SU_L(2)$ gauge group on the off-shell $WW\\gamma$ and $WWZ$ vertices is calculated in the context of a pure Yang-Mills theory in five dimensions and its phenomenological implications discussed. The use of a gauge-fixing procedure for the excited KK modes that is covariant under the standard gauge transformations of the $SU_L(2)$ group is stressed. A gauge-fixing term and the Faddeev-pov ghost sector for the KK gauge modes that are separately invariant under the standard gauge transformations of $SU_L(2)$ are presented. It is shown that the contributions of the KK modes to the off shell $WW\\gamma$ and $WWZ$ vertices are free of ultraviolet divergences and well-behaved at high energies. It is found that for a size of the fifth dimension of the order of 1 TeV, the one-loop contribution of the KK modes to these vertices is about one order of magnitude lower than the corresponding standard model radiative correction. This contribution is simil...
One-loop effects on MSSM parameter determination via chargino production at the LC
Energy Technology Data Exchange (ETDEWEB)
Bharucha, Aoife [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kalinowski, Jan [Warsaw Univ. (Poland). Faculty of Physics; Moortgat-Pick, Gudrid [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Rolbiecki, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); IFT-UAM/CSIC, Madrid (Spain). Inst. de Fisica Teorica; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-11-15
At a future linear collider very precise measurements, typically with errors of <1%, are expected to be achievable. Such an accuracy gives sensitivity to the quantum corrections, which therefore must be incorporated in theoretical calculations in order to determine the underlying new physics parameters from prospective linear collider measurements. In the context of the chargino-neutralino sector of the minimal supersymmetric standard model, this involves fitting one-loop predictions to prospective measurements of the cross sections, forward-backward asymmetries and of the accessible chargino and neutralino masses. Taking recent results from LHC SUSY and Higgs searches into account we consider three benchmark scenarios, each with characteristic features. Our analysis shows how an accurate determination of the desired parameters is possible, providing in addition access to the stop masses and mixing angle.
One-loop effects on MSSM parameter determination via chargino production at the LC
Energy Technology Data Exchange (ETDEWEB)
Bharucha, Aoife [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kalinowski, Jan [Warsaw Univ. (Poland). Faculty of Physics; Moortgat-Pick, Gudrid [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Rolbiecki, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); IFT-UAM/CSIC, Madrid (Spain). Inst. de Fisica Teorica; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2012-11-15
At a future linear collider very precise measurements, typically with errors of <1%, are expected to be achievable. Such an accuracy gives sensitivity to the quantum corrections, which therefore must be incorporated in theoretical calculations in order to determine the underlying new physics parameters from prospective linear collider measurements. In the context of the chargino-neutralino sector of the minimal supersymmetric standard model, this involves fitting one-loop predictions to prospective measurements of the cross sections, forward-backward asymmetries and of the accessible chargino and neutralino masses. Taking recent results from LHC SUSY and Higgs searches into account we consider three benchmark scenarios, each with characteristic features. Our analysis shows how an accurate determination of the desired parameters is possible, providing in addition access to the stop masses and mixing angle.
QCD One-Loop Effective Coupling Constant and Quark Mass Given in a Mass-Dependent Renormalization
Institute of Scientific and Technical Information of China (English)
SU Jun-Chen; SHAN Lian-You; CAO Ying-Hui
2001-01-01
The QCD one-loop renormalization is restudied in a mass-dependent subtraction scheme in which the quark mass is not set to vanish and the renormalization point is chosen to be an arbitrary time-like momentum. The correctness of the subtraction is ensured by the Ward identities which are respected in all the processes of subtraction.By considering the mass effect, the effective coupling constant and the effective quark masses derived by solving the renormalization group equations are given in improved expressions which are different from the previous results.PACS numbers: 11.10.Gh, 11.10.Hi, 12.38.-t, 12.38.Bx
One loop effects of natural SUSY in third generation fermion production at the ILC
Kouda, Yusaku; Kurihara, Yoshimasa; Ishikawa, Tadashi; Jimbo, Masato; Kato, Kiyoshi; Kuroda, Masaaki
2016-01-01
We investigate the 1-loop effects of supersymmetric particles on the third-generation fermion-pair production at the ILC within the framework of the Minimal Supersymmetric Standard Model. Three sets of the SUSY parameters are proposed which are consistent with the observed Higgs mass, the muon $g$-$2$, the Dark Matter abundance, etc. We discuss on the possibility of discovering the signals consistent with SUSY as well as of experimentally distinguishing the proposed sets of SUSY parameters.
Resumming the POPE at One Loop
Lam, Ho Tat
2016-01-01
The Pentagon Operator Product Expansion represents polygonal Wilson loops in planar $\\mathcal{N}=4$ super Yang-Mills in terms of a series of flux tube excitations for finite coupling. We demonstrate how to re-sum this series at the one loop level for the hexagonal Wilson loop dual to the six-point MHV amplitude. By summing over a series of effective excitations we find expressions which integrate to logarithms and polylogarithms, reproducing the known one-loop result.
One-loop Matching and Running with Covariant Derivative Expansion
Henning, Brian; Murayama, Hitoshi
2016-01-01
We develop tools for performing effective field theory (EFT) calculations in a manifestly gauge-covariant fashion. We clarify how functional methods account for one-loop diagrams resulting from the exchange of both heavy and light fields, as some confusion has recently arisen in the literature. To efficiently evaluate functional traces containing these "mixed" one-loop terms, we develop a new covariant derivative expansion (CDE) technique that is capable of evaluating a much wider class of traces than previous methods. The technique is detailed in an appendix, so that it can be read independently from the rest of this work. We review the well-known matching procedure to one-loop order with functional methods. What we add to this story is showing how to isolate one-loop terms coming from diagrams involving only heavy propagators from diagrams with mixed heavy and light propagators. This is done using a non-local effective action, which physically connects to the notion of "integrating out" heavy fields. Lastly...
Energy Technology Data Exchange (ETDEWEB)
S. Pastore,L. Girlanda,R. Schiavilla,M. Viviani,S. Pastore,L. Girlanda,R. Schiavilla,M. Viviani
2011-08-01
The electromagnetic charge operator in a two-nucleon system is derived in chiral effective field theory ($\\chi$EFT) up to order $e\\, Q$ (or N4LO), where $Q$ denotes the low-momentum scale and $e$ is the electric charge. The specific form of the N3LO and N4LO corrections from, respectively, one-pion-exchange and two-pion-exchange depends on the off-the-energy-shell prescriptions adopted for the non-static terms in the corresponding potentials. We show that different prescriptions lead to unitarily equivalent potentials and accompanying charge operators. Thus, provided a consistent set is adopted, predictions for physical observables will remain unaffected by the non-uniqueness associated with these off-the-energy-shell effects.
Covariant diagrams for one-loop matching
Zhang, Zhengkang
2016-01-01
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gauge-covariant quantities and are thus dubbed "covariant diagrams." The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
Covariant diagrams for one-loop matching
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhengkang [Michigan Univ., Ann Arbor, MI (United States). Michigan Center for Theoretical Physics; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2016-10-15
We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gaugecovariant quantities and are thus dubbed ''covariant diagrams.'' The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.
One-loop Partition Functions of 3D Gravity
Giombi, Simone; Yin, Xi
2008-01-01
We consider the one-loop partition function of free quantum field theory in locally Anti-de Sitter space-times. In three dimensions, the one loop determinants for scalar, gauge and graviton excitations are computed explicitly using heat kernel techniques. We obtain precisely the result anticipated by Brown and Henneaux: the partition function includes a sum over "boundary excitations" of AdS3, which are the Virasoro descendants of empty Anti-de Sitter space. This result also allows us to compute the one-loop corrections to the Euclidean action of the BTZ black hole as well its higher genus generalizations.
Reyes, Carlos M.; Urrutia, L. F.
2017-01-01
We study perturbative unitarity in a Lorentz-symmetry-violating QED model with higher-order derivative operators in the light of the results of Lee and Wick to preserve unitarity in indefinite metric theories. Specifically, we consider the fermionic sector of the Myers-Pospelov model, which includes dimension-five operators, coupled to standard photons. We canonically quantize the model, paying attention to its effective character, and show that its Hamiltonian is stable, emphasizing the exact stage at which the indefinite metric appears and decomposes into a positive-metric sector and a negative-metric sector. Finally, we verify the optical theorem at the one-loop level in the annihilation channel of the forward-scattering process e+(p2,r )+e-(p1,s ) by applying the Lee-Wick prescription, in which the states associated with the negative metric are left out from the asymptotic Hilbert space, but nevertheless are considered in the loop integration via the propagator.
One loop divergences and anomalies from chiral superfields in supergravity
Butter, Daniel
2009-01-01
We apply the heat kernel method (using Avramidi's non-recursive technique) to the study of the effective action of chiral matter in a complex representation of an arbitrary gauge sector coupled to background U(1) supergravity. This generalizes previous methods, which restricted to 1) real representations of the gauge sector in traditional Poincar\\'e supergravity or 2) vanishing supergravity background. In this new scheme, we identify a classical ambiguity in these theories which mixes the supergravity U(1) with the gauge U(1). At the quantum level, this ambiguity is maintained since the effective action changes only by a local counterterm as one shifts a U(1) factor between the supergravity and gauge sectors. An immediate application of our formalism is the calculation of the one-loop gauge, Kahler, and reparametrization anomalies of chiral matter coupled to minimal supergravity from purely chiral loops. Our approach gives an anomaly whose covariant part is both manifestly supersymmetric and non-perturbative ...
A supersymmetric exotic field theory in (1+1) dimensions. One loop soliton quantum mass corrections
Aguirre, A R
2016-01-01
We consider one loop quantum corrections to soliton mass for the $N=1$ supersymmetric extension of the $\\phi^2 \\cos^2(\\ln \\phi^2)$ scalar field theory in (1+1) dimensions. First, we compute the one loop quantum soliton mass correction of the bosonic sector by using a mixture of the scattering phase shift and the Euclidean effective action technique. Afterwards the computation in the supersymmetric case is naturally extended by considering the fermionic phase shifts associated to the Majorana fields. As a result we derive a general formula for the one loop quantum corrections to the soliton mass of the SUSY kink, and obtain for this exotic model the same value as for the SUSY sine-Gordon and $\\phi^4$ models.
A convergent series for the QED effective action.
Cho, Y M; Pak, D G
2001-03-05
The one-loop effective action of QED obtained by Heisenberg and Euler and by Schwinger has been expressed by an asymptotic perturbative series which is divergent. In this Letter we present a nonperturbative but convergent series of the effective action. With the convergent series we establish the existence of the manifest electric-magnetic duality in the one-loop effective action of QED.
On the one loop corrections to inflation and the CMB anisotropies
DEFF Research Database (Denmark)
Sloth, Martin Snoager
2006-01-01
We investigate the one loop effective potential of inflation in a standard model of chaotic inflation. The leading one loop corrections to the effective inflaton potential are evaluated in the quasi de Sitter background, and we estimate the one loop correction to the two-point function of the inf...
Integrand reduction beyond one-loop calculations
Ossola, Giovanni
2016-01-01
In this presentation, we review the general features of integrand-reduction techniques, with a particular focus on their generalization beyond one loop. We start with a brief discussion of the one-loop scenario, a case in which integrand-reduction algorithms are well established and played over the past decade an important role in the development of automated tools for the theoretical evaluation of physical observables. The generalization of integrand-reduction techniques to all loops has been the subject of several efforts in the recent past, thus providing a better understanding of the universal properties of scattering amplitudes. The ultimate goal of these studies is the development of efficient alternative computational techniques for the evaluation of Feynman integrals beyond one loop.
Quenched chiral perturbation theory to one loop
Colangelo, Gilberto; Pallante, Elisabetta
1998-01-01
We calculate the divergences of the generating functional of quenched chiral perturbation theory at one loop, and renormalize the theory by an appropriate definition of the counterterms. We show that the quenched chiral logarithms can be accounted for by defining a renormalized B0 parameter which, a
Quenched Chiral Perturbation Theory to one loop
Colangelo, G.; Pallante, E.
1998-01-01
The divergences of the generating functional of quenched Chiral Perturbation theory (qCHPT) to one loop are computed in closed form. We show how the quenched chiral logarithms can be reabsorbed in the renormalization of the B0 parameter of the leading order Lagrangian. Finally, we do the chiral powe
Polynomial structures in one-loop amplitudes
Britto, R.; Feng, B.; Yang, G.
2008-01-01
A general one-loop scattering amplitude may be expanded in terms of master integrals. The coefficients of the master integrals can be obtained from tree-level input in a two-step process. First, use known formulas to write the coefficients of (4-2epsilon)-dimensional master integrals; these formulas
Integral coefficients for one-loop amplitudes
Britto, R.; Feng, B.
2008-01-01
We present a set of algebraic functions for evaluating the coefficients of the scalar integral basis of a general one-loop amplitude. The functions are derived from unitarity cuts, but the complete cut-integral procedure has been carried out in generality so that it never needs to be repeated. Where
One-loop non-renormalization results in EFTs
Directory of Open Access Journals (Sweden)
J. Elias-Miró
2015-07-01
Full Text Available In Effective Field Theories (EFTs with higher-dimensional operators many anomalous dimensions vanish at the one-loop level. With the use of supersymmetry, and a classification of the operators according to their embedding in super-operators, we are able to understand why many of these anomalous dimensions are zero. The key observation is that one-loop contributions from superpartners trivially vanish in many cases under consideration, making the superfield formalism a powerful tool even for non-supersymmetric models. We show this in detail in a simple U(1 model with a scalar and fermions, and explain how to extend this to SM EFTs and the QCD Chiral Lagrangian. This provides an understanding of why most “current–current” operators do not renormalize “loop” operators at the one-loop level, and allows to find the few exceptions to this ubiquitous rule.
Automated one-loop calculations with GOSAM
Energy Technology Data Exchange (ETDEWEB)
Cullen, Gavin [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, Nicolas [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Physics; Max-Planck-Institut fuer Physik, Muenchen (Germany); Heinrich, Gudrun; Reiter, Thomas [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, Gionata [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, Pierpaolo [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, Giovanni [New York City Univ., NY (United States). New York City College of Technology; New York City Univ., NY (United States). The Graduate School and University Center; Tramontano, Francesco [European Organization for Nuclear Research (CERN), Geneva (Switzerland)
2011-11-15
We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop. (orig.)
One-loop Noncommutative U(1) Gauge Theory from Bosonic Worldline Approach
Kiem, Y H; Ryou, C; Sato, H T; Kiem, Youngjai; Kim, Yeonjung; Ryou, Cheol; Sato, Haru-Tada
2002-01-01
We develop a method to compute the one-loop effective action of noncommutative U(1) gauge theory based on the bosonic worldline formalism, and derive compact expressions for N-point 1PI amplitudes. The method, resembling perturbative string computations, shows that open Wilson lines emerge as a gauge invariant completion of certain terms in the effective action. The terms involving open Wilson lines are of the form reminiscent of closed string exchanges between the states living on the two boundaries of a cylinder. They are also consistent with recent matrix theory analysis and the results from noncommutative scalar field theories with cubic interactions.
One-loop divergences in massive gravity theory
Buchbinder, Ioseph L; Shapiro, Ilya L
2012-01-01
The one-loop divergences are calculated for the recently proposed ghost-free version of massive gravity, where the action depends on both metric and external tensor field f. The non-polynomial structure of the massive term is reduced to a more standard form by means of auxiliary tensor field, which is settled on-shell after quantum calculations are performed. As one should expect, the counterterms do not reproduce the form of the classical action. Moreover, the result has the form of the power series in f.
One-loop divergences in massive gravity theory
Buchbinder, I. L.; Pereira, D. D.; Shapiro, I. L.
2012-05-01
The one-loop divergences are calculated for the recently proposed ghost-free massive gravity model, where the action depends on both metric and external tensor field f. The non-polynomial structure of the massive term is reduced to a more standard form by means of auxiliary tensor field, which is settled on-shell after quantum calculations are performed. As one should expect, the counter-terms do not reproduce the form of the classical action. Moreover, the result has the form of the power series in f.
Dimensionally regulated one-loop integrals
Bern, Z; Kosower, D A
1993-01-01
We describe methods for evaluating one-loop integrals in $4-2\\e$ dimensions. We give a recursion relation that expresses the scalar $n$-point integral as a cyclicly symmetric combination of $(n-1)$-point integrals. The computation of such integrals thus reduces to the calculation of box diagrams ($n=4$). The tensor integrals required in gauge theory may be obtained by differentiating the scalar integral with respect to certain combinations of the kinematic variables. Such relations also lead to differential equations for scalar integrals. For box integrals with massless internal lines these differential equations are easy to solve.
Modern Feynman Diagrammatic One-Loop Calculations
Reiter, Thomas; Greiner, Nicolas; Guffanti, Alberto; Guillet, Jean-Philippe; Heinrich, Gudrun; Karg, Stefan; Kauer, Nikolas; Kleinschmidt, Tobias; Koch-Janusz, Maciej; Luisoni, Gionata; Mastrolia, Pierpaolo; Ossola, Giovanni; Pilon, Eric; Rodgers, Mark; Tramontano, Francesco; Wigmore, Ioan
2010-01-01
In this talk we present techniques for calculating one-loop amplitudes for multi-leg processes using Feynman diagrammatic methods in a semi-algebraic context. Our approach combines the advantages of the different methods allowing for a fast evaluation of the amplitude while monitoring the numerical stability of the calculation. In phase space regions close to singular kinematics we use a method avoiding spurious Gram determinants in the calculation. As an application of our approach we report on the status of the calculation of the amplitude for the process $pp\\to b\\bar{b}b\\bar{b}+X$.
Minimally doubled fermions at one-loop level
Capitani, Stefano; Wittig, Hartmut
2009-01-01
Single fermionic degrees of freedom together with standard chiral symmetry at finite lattice spacing, correct continuum limit and local interactions only are precluded by the Nielsen-Ninomiya no-go theorem. The class of minimally doubled fermion actions exhibits exactly two chiral modes. Recent interest in these actions has been sparked by the investigation of fermionic actions defined on "hyperdiamond" lattices. Due to the necessity of breaking hypercubic symmetry explicitly, radiative corrections generate operator mixings with relevant and marginal operators that should vanish in continuum QCD. These cannot be avoided and must be taken into account in particular by a peculiar wave-function renormalisation and additive momentum renormalisation. Renormalisation properties at one-loop level of the self-energy, local bilinears and conserved vector and axial-vector currents are presented for Borici-Creutz and Karsten-Wilczek actions. Distinct differences and similarities between both actions are elucidated.
One-loop nonlinear correction for QED
Furtado, J. S. N.; Silva, G. R.
2016-08-01
In this work, we study the generation of a nonlinear correction for QED, namely, the Euler-Heisenberg effective action. In order to achieve this, we consider two methods. The first method employed consists in make use of Feynman parametrization to solve the integrals properly, while in the second method a derivative expansion in the external momentum was considered.
Kalinichenko, I S
2016-01-01
The explicit expressions for the high-temperature expansions of the one-loop corrections to the omega-potential coming from the charged scalar and Dirac particles and, separately, from antiparticles in a constant homogeneous magnetic field are derived. The explicit expressions for the non-perturbative corrections to the effective action at finite temperature and density are obtained. The thermodynamic properties of a gas of charged scalars in a constant homogeneous magnetic field are analyzed in the one-loop approximation. It turns out that, in this approximation, the system suffers the first order phase transition from the diamagnetic to the superconducting state at sufficiently high densities. The improvement of the one-loop result by summing the ring diagrams is investigated. This improvement leads to a drastic change of the thermodynamic properties of the system. The gas of charged scalars passes to the ferromagnetic state in place of the superconducting one at high densities and sufficiently low temperat...
On the One Loop Corrections to Inflation II
DEFF Research Database (Denmark)
Sloth, Martin Snoager
2006-01-01
model of chaotic inflation with a quadratic inflationary potential. We discuss the physical interpretation of the effect in terms of the tensor-to-scalar consistency relation. Finally, we discuss the relation to the work of Weinberg on quantum contributions to cosmological correlators.......In this paper we extend our previous treatment of the one-loop corrections to inflation. Previously we calculated the one-loop corrections to the background and the two-point correlation function of inflaton fluctuations in a specific model of chaotic inflation. We showed that the loop corrections...... depend on the total number of e-foldings and estimated that the effect could be as large as a few percent in a lambda-phi-four model of chaotic inflation. In the present paper we generalize the calculations to general inflationary potentials. We find that effect can be as large as 70% in the simplest...
Effective action for stochastic partial differential equations
Energy Technology Data Exchange (ETDEWEB)
Hochberg, David [Laboratorio de Astrofisica Espacial y Fisica Fundamental, Apartado 50727, 28080 Madrid, (Spain); Centro de Astrobiologia, INTA, Carratera Ajalvir, Km. 4, 28850 Torrejon, Madrid, (Spain); Molina-Paris, Carmen [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Perez-Mercader, Juan [Laboratorio de Astrofisica Espacial y Fisica Fundamental, Apartado 50727, 28080 Madrid, (Spain); Visser, Matt [Physics Department, Washington University, Saint Louis, Missouri 63130-4899 (United States)
1999-12-01
Stochastic partial differential equations (SPDEs) are the basic tool for modeling systems where noise is important. SPDEs are used for models of turbulence, pattern formation, and the structural development of the universe itself. It is reasonably well known that certain SPDEs can be manipulated to be equivalent to (nonquantum) field theories that nevertheless exhibit deep and important relationships with quantum field theory. In this paper we systematically extend these ideas: We set up a functional integral formalism and demonstrate how to extract all the one-loop physics for an arbitrary SPDE subject to arbitrary Gaussian noise. It is extremely important to realize that Gaussian noise does not imply that the field variables undergo Gaussian fluctuations, and that these nonquantum field theories are fully interacting. The limitation to one loop is not as serious as might be supposed: Experience with quantum field theories (QFTs) has taught us that one-loop physics is often quite adequate to give a good description of the salient issues. The limitation to one loop does, however, offer marked technical advantages: Because at one loop almost any field theory can be rendered finite using zeta function technology, we can sidestep the complications inherent in the Martin-Siggia-Rose formalism (the SPDE analog of the Becchi-Rouet-Stora-Tyutin formalism used in QFT) and instead focus attention on a minimalist approach that uses only the physical fields (this ''direct approach'' is the SPDE analog of canonical quantization using physical fields). After setting up the general formalism for the characteristic functional (partition function), we show how to define the effective action to all loops, and then focus on the one-loop effective action and its specialization to constant fields: the effective potential. The physical interpretation of the effective action and effective potential for SPDEs is addressed and we show that key features carry over from
Effective action for stochastic partial differential equations.
Hochberg, D; Molina-París, C; Pérez-Mercader, J; Visser, M
1999-12-01
Stochastic partial differential equations (SPDEs) are the basic tool for modeling systems where noise is important. SPDEs are used for models of turbulence, pattern formation, and the structural development of the universe itself. It is reasonably well known that certain SPDEs can be manipulated to be equivalent to (nonquantum) field theories that nevertheless exhibit deep and important relationships with quantum field theory. In this paper we systematically extend these ideas: We set up a functional integral formalism and demonstrate how to extract all the one-loop physics for an arbitrary SPDE subject to arbitrary Gaussian noise. It is extremely important to realize that Gaussian noise does not imply that the field variables undergo Gaussian fluctuations, and that these nonquantum field theories are fully interacting. The limitation to one loop is not as serious as might be supposed: Experience with quantum field theories (QFTs) has taught us that one-loop physics is often quite adequate to give a good description of the salient issues. The limitation to one loop does, however, offer marked technical advantages: Because at one loop almost any field theory can be rendered finite using zeta function technology, we can sidestep the complications inherent in the Martin-Siggia-Rose formalism (the SPDE analog of the Becchi-Rouet-Stora-Tyutin formalism used in QFT) and instead focus attention on a minimalist approach that uses only the physical fields (this "direct approach" is the SPDE analog of canonical quantization using physical fields). After setting up the general formalism for the characteristic functional (partition function), we show how to define the effective action to all loops, and then focus on the one-loop effective action and its specialization to constant fields: the effective potential. The physical interpretation of the effective action and effective potential for SPDEs is addressed and we show that key features carry over from QFT to the case of
Universality and ambiguity in fermionic effective actions
de Berredo-Peixoto, Guilherme; Shapiro, Ilya L
2012-01-01
We discuss an ambiguity in the one-loop effective action of massive fields which takes place in massive fermionic theories. The universality of logarithmic UV divergences in different space-time dimensions leads to the non-universality of the finite part of effective action, which can be called the non-local multiplicative anomaly. The general criteria of existence of this phenomena are formulated and applied to fermionic operators with different external fields.
On the one loop corrections to inflation and the CMB anisotropies
Energy Technology Data Exchange (ETDEWEB)
Sloth, Martin S. [Department of Physics, University of California, Davis, CA 95616 (United States)]. E-mail: sloth@physics.ucdavis.edu
2006-07-31
We investigate the one loop effective potential of inflation in a standard model of chaotic inflation. The leading one loop corrections to the effective inflaton potential are evaluated in the quasi de Sitter background, and we estimate the one loop correction to the two-point function of the inflaton perturbations in the Hartree approximation. In this approximation, the one loop corrections depends on the total number of e-foldings of inflation and the maximal effect is estimated to be a correction to the power spectrum of a few percent. However, such a correction may be difficult to disentangle from the background in the simplest scenario.
On the one loop corrections to inflation and the CMB anisotropies
Sloth, M S
2006-01-01
We investigate the one loop effective potential of inflation in a standard model of chaotic inflation. The leading one loop corrections to the effective inflaton potential are evaluated in the quasi de Sitter background, and we estimate the one loop correction to the two-point function of the inflaton perturbations in the Hartree approximation. In this approximation, the one loop corrections depends on the total number of e-foldings of inflation and the maximal effect is estimated to be a correction to the power spectrum of a few percent. However, such a correction may be difficult to disentangle from the background in the simplest scenario.
Direct Extraction of One Loop Rational Terms
Badger, S D
2009-01-01
We present a method for the direct extraction of rational contributions to one-loop scattering amplitudes, missed by standard four-dimensional unitarity techniques. Working in D=4-2*epsilon dimensions, we interpret the dependence on the additional dimensions as equivalent to introducing an internal mass. We combine this with the use of generalised unitarity to write the loop amplitudes in terms of products of massive tree amplitudes. We find that the rational terms in 4-2*epsilon dimensions can be determined from quadruple, triple and double cuts without the need for independent pentagon contributions using a massive integral basis. The additional mass-dependent integral coefficients may then be extracted analytically or numerically using discrete Fourier projections. We check the method by computing the rational parts of all gluon helicity amplitudes with up to six external legs.
One-loop Yukawa couplings in local models
Energy Technology Data Exchange (ETDEWEB)
Conlon, Joseph P. [Rudolf Peierls Center for Theoretical Physics, Oxford (United Kingdom); Balliol College, Oxford (United Kingdom); Goodsell, Mark [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Palti, Eran [Centre de Physique Theorique, Ecole Polytechnique, CNRS, Palaiseau (France)
2010-07-15
We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops. (orig.)
Singularity-free cosmological solutions of the superstring effective action
Energy Technology Data Exchange (ETDEWEB)
Antoniadis, I. (Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique Theorique); Rizos, J. (Ecole Polytechnique, 91 - Palaiseau (France). Centre de Physique Theorique); Tamvakis, K. (Ioannina Univ. (Greece). Dept. of Physics)
1994-03-07
We study the cosmological solutions of the one-loop corrected superstring effective action, in a Friedmann-Robertson-Walker background, and in the presence of the dilaton and modulus fields. A particularly interesting class of solutions is found which avoid the initial singularity and are consistent with the perturbative treatment of the effective action. (orig.)
Gauge dependence of the effective action in Einstein gravity
Energy Technology Data Exchange (ETDEWEB)
Lavrov, P.M.; Reshetnyak, A.A. [Tomsk State Pedagogical Institute (Russian Federation)
1995-10-01
Einstein gravity is considered in a special one-parameter background gauge. The one-loop effective action of the theory is calculated to the first order in the gauge parameter. It is shown that, on the mass shell, the effective action is independent of the gauge parameter. 57 refs.
One-loop diagrams in the random Euclidean matching problem
Lucibello, Carlo; Parisi, Giorgio; Sicuro, Gabriele
2017-01-01
The matching problem is a notorious combinatorial optimization problem that has attracted for many years the attention of the statistical physics community. Here we analyze the Euclidean version of the problem, i.e., the optimal matching problem between points randomly distributed on a d -dimensional Euclidean space, where the cost to minimize depends on the points' pairwise distances. Using Mayer's cluster expansion we write a formal expression for the replicated action that is suitable for a saddle point computation. We give the diagrammatic rules for each term of the expansion, and we analyze in detail the one-loop diagrams. A characteristic feature of the theory, when diagrams are perturbatively computed around the mean field part of the action, is the vanishing of the mass at zero momentum. In the non-Euclidean case of uncorrelated costs instead, we predict and numerically verify an anomalous scaling for the sub-sub-leading correction to the asymptotic average cost.
Worldsheet one-loop energy correction to IIA Giant Magnon
Bai, Xiaojian; Park, I Y
2013-01-01
We compute one-loop corrections to the energy of a IIA giant magnon solution in the $AdS_4 \\times CP^3$ background by using the standard quantum field theory (QFT) techniques. The string action is expanded around the solution to the quadratic order in the fluctuation fields. The resulting action has 2D coordinate dependent-coefficients, a feature that complicates the analysis. The solution contains a worldsheet velocity parameter $v$, and is expanded in terms of the parameter. A perturbative analysis is carried out by treating the $v$-dependent parts as vertices. The energy is computed by first putting the system in a box of length $L$ and Fourier-transforming the fields into the discrete momentum modes. We compare our result with the results obtained by the algebraic curve method.
Kalinichenko, Igor; Kazinski, Peter
2014-08-01
The explicit expressions for the one-loop non-perturbative corrections to the gravitational effective action induced by a scalar field on a stationary gravitational background are obtained both at zero and finite temperatures. The perturbative and non-perturbative contributions to the one-loop effective action are explicitly separated. It is proved that, after a suitable renormalization, the perturbative part of the effective action at zero temperature can be expressed in a covariant form solely in terms of the metric and its derivatives. This part coincides with the known large mass expansion of the one-loop effective action. The non-perturbative part of the renormalized one-loop effective action at zero temperature is proved to depend explicitly on the Killing vector defining the vacuum state of quantum fields. This part cannot be expressed in a covariant way through the metric and its derivatives alone. The implications of this result for the structure and symmetries of the effective action for gravity are discussed.
Kalinichenko, I S
2014-01-01
The explicit expressions for the one-loop non-perturbative corrections to the gravitational effective action induced by a scalar field on a stationary gravitational background are obtained both at zero and finite temperatures. The perturbative and non-perturbative contributions to the one-loop effective action are explicitly separated. It is proved that, after a suitable renormalization, the perturbative part of the effective action at zero temperature can be expressed in a covariant form solely in terms of the metric and its derivatives. This part coincides with the known large mass expansion of the one-loop effective action. The non-perturbative part of the renormalized one-loop effective action at zero temperature is proved to depend explicitly on the Killing vector defining the vacuum state of quantum fields. This part cannot be expressed in a covariant way through the metric and its derivatives alone. The implications of this result for the structure and symmetries of the effective action for gravity are...
One-loop lattice artifacts of a dynamical charm quark
Energy Technology Data Exchange (ETDEWEB)
Athenodorou, Andreas; Sommer, Rainer [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2011-10-15
For a few observables in O(a) improved lattice QCD, we compute discretization effects arising from the vacuum polarization of a heavy quark at one-loop order. In particular, the force between static quarks, the running coupling in the Schroedinger functional and a related quantity, anti {upsilon}, are considered. Results show that the cutoff effects of a dynamical charm quark are typically smaller than those present in the pure gauge theory. This perturbative result is a good indication that dynamical charm quarks are feasible already now. (orig.)
The five gluon amplitude and one-loop integrals
Bern, Zvi; Kosower, David A.
1992-01-01
We review the conventional field theory description of the string motivated technique. This technique is applied to the one-loop five-gluon amplitude. To evaluate the amplitude a general method for computing dimensionally regulated one-loop integrals is outlined including results for one-loop integrals required for the pentagon diagram and beyond. Finally, two five-gluon helicity amplitudes are given.
One-Loop Divergences in 6D Conformal Gravity
Pang, Yi
2012-01-01
Using Exact Renormalization Group Equation approach and background field method, we investigate the one-loop problem in a six-dimensional conformal gravity theory whose Lagrangian takes the same form as holographic Weyl anomaly of multiple coincident M5-branes. We choose the backgrounds to be the symmetric Einstein spaces including S6, CP3, S2 \\times S4, S2 \\times CP2, S3 \\times S3 and S2 \\times S2 \\times S2. Evaluating the functional sums gives power-law and logarithmic divergences. We extract from the specific values of logarithmic divergence on above backgrounds, the coefficient in front of Euler density and two linear equations constraining the coefficients in front of three type-B conformal invariants. As a test of the effectiveness of Exact Renormalization Group Equation approach to quantum conformal gravity, we reexaminethe one-loop problem in four-dimensional conformal gravity and confirm the logarithmic divergence derived from generalized Schwinger-DeWitt method.
On the calculation of effective actions by string methods
Schmidt, M G
1993-01-01
Strassler's formulation of the string-derived Bern-Kosower formalism is reconsidered with particular emphasis on effective actions and form factors. Two- and three point form factors in the nonabelian effective action are calculated and compared with those obtained in the heat kernel approach of Barvinsky, Vilkovisky et al. We discuss the Fock-Schwinger gauge and propose a manifestly covariant calculational scheme for one-loop effective actions in gauge theory.
Invariant measure of the one-loop quantum gravitational backreaction on inflation
Miao, S. P.; Tsamis, N. C.; Woodard, R. P.
2017-06-01
We use dimensional regularization in pure quantum gravity on a de Sitter background to evaluate the one-loop expectation value of an invariant operator which gives the local expansion rate. We show that the renormalization of this nonlocal composite operator can be accomplished using the counterterms of a simple local theory of gravity plus matter, at least at one-loop order. This renormalization completely absorbs the one-loop correction, which accords with the prediction that the lowest secular backreaction should be a two-loop effect.
Analytic results for the effective action
Blau, Steven K; Wipf, Andreas; 10.1142/S0217751X91002549
2009-01-01
Motivated by the seminal work of Schwinger, we obtain explicit closed form expressions for the one-loop effective action in a constant electromagnetic field. We discuss both massive and massless charged scalars and spinors in two, three, and four dimensions. Both strong field and weak field limits are calculable. The latter limit results in an asymptotic expansion whose first term reproduces the Euler-Heisenberg effective Lagrangian. We use the zeta function renormalization prescription, and indicate its relationship to Schwinger's renormalized effective action.
Transverse Ward-Takahashi Relation to One Loop
Institute of Scientific and Technical Information of China (English)
HEHan-Xin
2005-01-01
We calculate the transverse Ward-Takahashi relation for the vector vertex in momentum space at one-loop order in four-dimensional Abelian gauge theory. We demonstrate explicitly that the result is exactly the same as that derived by using one-loop vector vertex calculations.
A Numerical Unitarity Formalism for Evaluating One-Loop Amplitudes
Ellis, Richard Keith; Kunszt, Z
2008-01-01
Recent progress in unitarity techniques for one-loop scattering amplitudes makes a numerical implementation of this method possible. We present a 4-dimensional unitarity method for calculating the cut-constructible part of amplitudes and implement the method in a numerical procedure. Our technique can be applied to any one-loop scattering amplitude and offers the possibility that one-loop calculations can be performed in an automatic fashion, as tree-level amplitudes are currently done. Instead of individual Feynman diagrams, the ingredients for our one-loop evaluation are tree-level amplitudes, which are often already known. To study the practicality of this method we evaluate the cut-constructible part of the 4, 5 and 6 gluon one-loop amplitudes numerically, using the analytically known 4, 5 and 6 gluon tree-level amplitudes. Comparisons with analytic answers are performed to ascertain the numerical accuracy of the method.
One-loop gap equations for the magnetic mass in d=3 gauge theory
Cornwall, John M.
1998-03-01
Recently several workers have attempted determinations of the so-called magnetic mass of d=3 non-Abelian gauge theories through a one-loop gap equation, using a free massive propagator as input. Self-consistency is attained only on-shell, because the usual Feynman-graph construction is gauge-dependent off-shell. We examine two previous studies of the pinch technique proper self-energy, which is gauge-invariant at all momenta, using a free propagator as input, and show that it leads to inconsistent and unphysical results. In one case the residue of the pole has the wrong sign (necessarily implying the presence of a tachyonic pole); in the second case the residue is positive, but two orders of magnitude larger than the input residue, which shows that the residue is on the verge of becoming ghost-like. This happens because of the infrared instability of d=3 gauge theory. A possible alternative one-loop determination via the effective action also fails. The lesson is that gap equations must be considered at least at the two-loop level.
One-loop adjoint masses for non-supersymmetric intersecting branes
Energy Technology Data Exchange (ETDEWEB)
Anastasopoulos, P. [Technische Univ., Vienna (Austria). 1. Inst. fuer Theoretische Physik; Antoniadis, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Benakli, K. [CNRS, UPMC Univ. Paris (France). Lab. de Physique Theorique et Haute Energies; Goodsell, M.D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Vichi, A. [Institute de Theorie des Phenomenes Physiques, EPFL, Lausanne (Switzerland)
2011-05-15
We consider breaking of supersymmetry in intersecting D-brane configurations by slight deviation of the angles from their supersymmetric values. We compute the masses generated by radiative corrections for the adjoint scalars on the brane world-volumes. In the open string channel, the string two-point function receives contributions only from the infrared and the ultraviolet limits. The latter is due to tree-level closed string uncanceled NS-NS tadpoles, which we explicitly reproduce from the effective Born-Infeld action. On the other hand, the infrared region reproduces the one-loop mediation of supersymmetry breaking in the effective gauge theory, via messengers and their Kaluza-Klein excitations. In the toroidal set-up considered here, it receives contributions only from N {approx} 4 and N {approx} 2 supersymmetric configurations, and thus always leads at leading order to a tachyonic direction, in agreement with effective field theory expectations. (orig.)
Effective action approach to dynamical generation of fermion mixing
Blasone, Massimo; Smaldone, Luca
2016-01-01
In this paper we discuss a mechanism for the dynamical generation of flavor mixing, in the framework of the Nambu--Jona Lasinio model. Our approach is illustrated both with the conventional operatorial formalism and with functional integral and ensuing one-loop effective action. The results obtained are briefly discussed.
Effective action for a quantum scalar field in warped spaces
Energy Technology Data Exchange (ETDEWEB)
Hoff da Silva, J.M.; Mendonca, E.L.; Scatena, E. [Universidade Estadual Paulista ' ' Julio de Mesquita Filho' ' -UNESP, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil)
2015-11-15
We investigate the one-loop corrections, at zero as well as finite temperature, of a scalar field taking place in a braneworld motivated warped background. After to reach a well-defined problem, we calculate the effective action with the corresponding quantum corrections to each case. (orig.)
One-Loop Corrections to Five-Gluon Amplitudes
Bern, Z; Kosower, D A
1993-01-01
We present the one-loop helicity amplitudes with five external gluons. The computation employs string-based methods, new techniques for performing tensor integrals, and improvements in the spinor helicity method.
One-loop amplitudes on the Riemann sphere
National Research Council Canada - National Science Library
Geyer, Yvonne; Mason, Lionel; Monteiro, Ricardo; Tourkine, Piotr
2016-01-01
.... Their derivation from ambitwistor string theory led to proposals for formulae at one loop on a torus for 10 dimensional supergravity, and we recently showed how these can be reduced to the Riemann...
Boundary String Field Theory at One-loop
Lee, T; Yang, Y; Lee, Taejin; Yang, Yi
2001-01-01
We apply the boundary string field theory (BSFT) to a unstable D-brane system to study the open-closed string duality at one loop in the presence of the tachyon condensation. The partition function at one-loop level is calculated by using both open and closed string channels. We find that the results from two different channels coincide, thus the open-closed string duality holds even off-shell.
Results from GRACE/SUSY at one-loop
Indian Academy of Sciences (India)
J Fujimoto; T Ishikawa; M Jimbo; T Kaneko; T Kon; Y kurihara; M Kuroda; Y Shimizu; Y Yasui
2007-11-01
We report the recent development on the SUSY calculations with the help of GRACE system. GRACE/SUSY/1LOOP is the computer code which can generate Feynman diagrams in the MSSM automatically and compute one-loop amplitudes in the numerical way. We present new results of various two-body decay widths and chargino pair production at ILC (international linear collider) at one-loop level.
One loop graviton corrections to dynamical photons in de Sitter
Glavan, D; Prokopec, Tomislav; Woodard, R P
2016-01-01
We employ a recent, general gauge computation of the one loop graviton contribution to the vacuum polarization on de Sitter to solve for one loop corrections to the photon mode function. The vacuum polarization takes the form of a gauge independent, spin 2 contribution and a gauge dependent, spin 0 contribution. We show that the leading secular corrections derive entirely from the spin 2 contribution.
LOOL: Mathematica package for evaluating leading order one loop functions
Ilakovac, Amon; Popov, Luka
2014-01-01
One-loop functions with loop masses larger than external masses and momenta can always be expanded in terms of external masses and momenta. The precision requested for observables determines the number of the expansion terms retained in the evaluation. The evaluation of these expansion terms turns out to be much simpler than the exact evaluation of the corresponding one-loop function. Here we present the program which evaluates those expansion terms. This Mathematica package provides two subr...
LOOL: Mathematica package for evaluating leading order one loop functions
Ilakovac, Amon
2014-01-01
One-loop functions with loop masses larger than external masses and momenta can always be expanded in terms of external masses and momenta. The precision requested for observables determines the number of the expansion terms retained in the evaluation. The evaluation of these expansion terms turns out to be much simpler than the exact evaluation of the corresponding one-loop function. Here we present the program which evaluates those expansion terms. This Mathematica package provides two subroutines. First one performs analytical evaluation of basic one loop integrals. The second one is used to construct composite functions out of those integrals. Composite functions thus obtained are ready for numerical evaluation with literary no time consumption.
Superstring one-loop and gravitino contributions to planckian scattering
Bellini, Alessandro; Ademollo, Marco; Ciafaloni, Marcello
1993-03-01
Corrections to the semiclassical approximation in nearly forward planckian energy collisions are reconsidered. Starting from the one-loop superstring amplitude, we are able to disentangle the first subleading high-energy contribution at large impact parameters, and we thus directly compute the one-loop correction to the superstring eikonal. By comparing this result with previous ones by Amati, Ciafaloni and Veneziano (ACV) for pure gravity, we identify one-loop gravitino contributions which agree with previous results by Lipatov. We finally argue, on the basis of analyticity and unitarity, that gravitinos do not contribute at all the large-distance two-loop ACV correction, which thus acquires a universal "classical" interpretation.
Automated one-loop calculations with GoSam
Energy Technology Data Exchange (ETDEWEB)
Cullen, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, N.; Heinrich, G.; Reiter, T. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, G. [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, P. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, G. [City Univ. of New York, NY (United States). New York City College of Technology; Tramontano, F. [CERN, Geneva (Switzerland). AS Div.
2012-01-15
In this talk, the program package GOSAM is presented which can be used for the automated calculation of one-loop amplitudes for multi-particle processes. The integrands are generated in terms of Feynman diagrams and can be reduced by d-dimensional integrand-level decomposition, or tensor reduction, or a combination of both. Through various examples we show that GOSAM can produce one-loop amplitudes for both QCD and electroweak theory; model files for theories Beyond the Standard Model can be linked as well. (orig.)
Gravitino one-loop contribution to Planckian Scattering
Bellini, A; Ciafaloni, Marcello
1993-01-01
Corrections to the semiclassical approximation in nearly forward Planckian energy collisions are here reconsidered. Starting from the one-loop superstring amplitude, we are able to disentangle the first subleading high-energy contribution at large impact parameters, and we thus directly compute the one-loop correction to the superstring eikonal. We finally argue, on the basis of analyticity and unitarity, that gravitinos do not contribute at all to the large distance two-loop ACV correction, which thus acquires a universal ``classical'' interpretation.
One-loop radiative corrections to the QED Casimir energy
Energy Technology Data Exchange (ETDEWEB)
Moazzemi, Reza; Mojavezi, Amirhosein [University of Qom, Department of Physics, Qom (Iran, Islamic Republic of)
2016-05-15
In this paper, we investigate one-loop radiative corrections to the Casimir energy in the presence of two perfectly conducting parallel plates for QED theory within the renormalized perturbation theory. In fact, there are three contributions for radiative corrections to the Casimir energy, up to order α, has been computed by Bordag et. al (Ann. Phys. 165:192, 1985), approximately. Here, up to this order, we consider corrections due to two one-loop terms, i.e., photonic and fermionic loop corrections resulting from renormalized QED Lagrangian, more precisely. Our results show that only the fermionic loop has a very minor correction and the correction of photonic loop vanishes. (orig.)
Recursive generation of one-loop SM amplitudes
Energy Technology Data Exchange (ETDEWEB)
Actis, Stefano [Paul Scherrer Institut, Wuerenlingen (Switzerland); Paul Scherrer Institut, Villigen (Switzerland); Denner, Ansgar; Hofer, Lars; Scharf, Andreas [Universitaet Wuerzburg (Germany); Uccirati, Sandro [Universita di Torino, Turin (Italy)
2013-07-01
We introduce the computer code Recola for the recursive generation of tree-level and one-loop amplitudes in the full Standard Model, including electroweak corrections. The presented algorithm for the calculation of one-loop amplitudes uses Dyson-Schwinger recursion relations to determine the coefficients of the tensor integrals. As a first application of Recola we discuss Z+2jets production at the LHC and present results for the next-to-leading-order electroweak corrections to the dominant partonic channels.
One Loop Renormalization of the Littlest Higgs Model
Grinstein, Benjamin; Uttayarat, Patipan
2011-01-01
In Little Higgs models a collective symmetry prevents the Higgs from acquiring a quadratically divergent mass at one loop. This collective symmetry is broken by weakly gauged interactions. Terms, like Yukawa couplings, that display collective symmetry in the bare Lagrangian are generically renormalized into a sum of terms that do not respect the collective symmetry except possibly at one renormalization point where the couplings are related so that the symmetry is restored. We study here the one loop renormalization of a prototypical example, the Littlest Higgs Model. Some features of the renormalization of this model are novel, unfamiliar form similar chiral Lagrangian studies.
Loop expansion of the average effective action in the functional renormalization group approach
Lavrov, Peter M.; Merzlikin, Boris S.
2015-10-01
We formulate a perturbation expansion for the effective action in a new approach to the functional renormalization group method based on the concept of composite fields for regulator functions being their most essential ingredients. We demonstrate explicitly the principal difference between the properties of effective actions in these two approaches existing already on the one-loop level in a simple gauge model.
Loop expansion of average effective action in functional renormalization group approach
Lavrov, Peter M
2015-01-01
We formulate a perturbation expansion for the effective action in new approach to the functional renormalization group (FRG) method based on concept of composite fields for regulator functions being therein most essential ingredients. We demonstrate explicitly the principal difference between properties of effective actions in these two approaches existing already on the one-loop level in a simple gauge model.
Anomalous effective action, Noether current, Virasoro algebra and Horizon entropy
Energy Technology Data Exchange (ETDEWEB)
Majhi, Bibhas Ranjan [IUCAA, Ganeshkhind, Pune University Campus, Post Bag 4, Pune (India); Hebrew University of Jerusalem, Racah Institute of Physics, Jerusalem (Israel); Chakraborty, Sumanta [IUCAA, Ganeshkhind, Pune University Campus, Post Bag 4, Pune (India)
2014-05-15
Several investigations show that in a very small length scale there exist corrections to the entropy of black hole horizon. Due to fluctuations of the background metric and the external fields the action incorporates corrections. In the low energy regime, the one-loop effective action in four dimensions leads to trace anomaly. We start from the Noether current corresponding to the Einstein-Hilbert plus the one-loop effective action to calculate the charge for the diffeomorphisms which preserve the Killing horizon structure. Then a bracket for the charges is calculated. We show that the Fourier modes of the bracket are exactly similar to the Virasoro algebra. Then using the Cardy formula the entropy is evaluated. Finally, the explicit terms of the entropy expression is calculated for a classical background. It turns out that the usual expression for the entropy; i.e. the Bekenstein-Hawking form, is not modified. (orig.)
One-loop amplitudes on the Riemann sphere
Geyer, Yvonne; Monteiro, Ricardo; Tourkine, Piotr
2016-01-01
The scattering equations provide a powerful framework for the study of scattering amplitudes in a variety of theories. Their derivation from ambitwistor string theory led to proposals for formulae at one loop on a torus for 10 dimensional supergravity, and we recently showed how these can be reduced to the Riemann sphere and checked in simple cases. We also proposed analogous formulae for other theories including maximal super-Yang-Mills theory and supergravity in other dimensions at one loop. We give further details of these results and extend them in two directions. Firstly, we propose new formulae for the one-loop integrands of Yang-Mills theory and gravity in the absence of supersymmetry. These follow from the identification of the states running in the loop as expressed in the ambitwistor-string correlator. Secondly, we give a systematic proof of the non-supersymmetric formulae using the worldsheet factorisation properties of the nodal Riemann sphere underlying the scattering equations at one loop. Our f...
One-loop tensor Feynman integral reduction with signed minors
DEFF Research Database (Denmark)
Fleischer, Jochem; Riemann, Tord; Yundin, Valery
2012-01-01
We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in ter...
One loop amplitude for Heterotic string on $T^2$
Sasmal, Soumya
2016-01-01
We revisit the results of one loop string amplitude calculations for the Heterotic string theory compactified on a torus with or without Wilson lines. We give the complete elliptic genus and the harmonic part of the CP-even amplitude for the gauge groups $SO(32)$, $E_8 \\times E_8$, $SO(16)^2$ and $SO(8)^4$.
Automation of one-loop calculations with GoSam
Energy Technology Data Exchange (ETDEWEB)
Soden-Fraunhofen, Johann Felix von [Max-Planck-Institut fuer Physik, Muenchen (Germany)
2012-07-01
The program package GoSam can be used to calculate multi-leg one-loop amplitudes within and beyond the Standard Model. An extension is additionally presented which allows to calculate integrals where the rank is larger than the number of propagators. One possible application of this feature is the calculation of QCD corrections within models involving extra dimensions.
Closed-form decomposition of one-loop massive amplitudes
Britto, R.; Feng, B.; Mastrolia, P.
2008-01-01
We present formulas for the coefficients of 2-, 3-, 4-, and 5-point master integrals for one-loop massive amplitudes. The coefficients are derived from unitarity cuts in D dimensions. The input parameters can be read off from any unitarity-cut integrand, as assembled from tree-level expressions,
Gauge-invariance in one-loop quantum cosmology
Vasilevich, D V
1995-01-01
We study the problem of gauge-invariance and gauge-dependence in one-loop quantum cosmology. We formulate some requirements which should be satisfied by boundary conditions in order to give gauge-independent path integral. The case of QED is studied in some detail. We outline difficulties in gauge-invariant quantization of gravitational field in a bounded region.
One-loop sfermion corrections to $e^{-}e^{+} \\to W^{-}W^{+}$ in the MSSM
Alam, S; Kanemura, S; Szalapski, R; Umeda, Y; Alam, Sher; Hagiwara, Kaoru; Kanemura, Shinya; Szalapski, Robert; Umeda, Yoshiaki
2000-01-01
We study one-loop effects of sfermions on helicity amplitudes for $\\eeww$ inthe Minimal Supersymmetric Standard Model. The one-loop contributions arecalculated in the $\\bar{\\rm MS}$ renormalization scheme. In order to verify thevalidity of the analytic calculation and the numerical program, the followingtests are performed. (i) The BRS sum rules hold exactly among the analyticexpressions of the form factors of the $\\eeww$ amplitude and those of theamplitudes where the external $W^\\pm$ bosons are replaced by the correspondingGoldstone bosons $\\chi^\\pm$, hence they hold within the expected accuracy ofthe numerical program. (ii) The one-loop sfermion contribution to theamplitudes decouple in the heavy mass limit. This property is used to test theoverall normalization of the amplitudes. In order to observe the analyticallyexact decoupling, the amplitudes are expanded by the $\\bar{\\rm MS}$ couplingsof the Standard Model. (iii) The high-energy analytic formulas of the helicityamplitudes, which are verified by using...
The one loop gluon emission light cone wave function
Lappi, Tuomas
2016-01-01
Light cone perturbation theory has become an essential tool to calculate cross sections for various small-$x$ dilute-dense processes such as deep inelastic scattering and forward proton-proton and proton-nucleus collisions. Here we set out to do one loop calculations in an explicit helicity basis in the four dimensional helicity scheme. As a first process we calculate light cone wave function for one gluon emission to one-loop order in Hamiltonian perturbation theory on the light front. We regulate ultraviolet divergences with transverse dimensional regularization and soft divergences with using a cut-off on longitudinal momentum. We show that when all the renormalization constants are combined, the ultraviolet divergences can be absorbed into the standard QCD running coupling constant, and give an explicit expression for the remaining finite part.
One Loop Mass Renormalization of Unstable Particles in Superstring Theory
Sen, Ashoke
2016-01-01
Most of the massive states in superstring theory are expected to undergo mass renormalization at one loop order. Typically these corrections should contain imaginary parts, indicating that the states are unstable against decay into lighter particles. However in such cases, direct computation of the renormalized mass using superstring perturbation theory yields divergent result. Previous approaches to this problem involve various analytic continuation techniques, or deforming the integral over the moduli space of the torus with two punctures into the complexified moduli space near the boundary. In this paper we use insights from string field theory to describe a different approach that gives manifestly finite result for the mass shift satisfying unitarity relations. The procedure is applicable to all states of (compactified) type II and heterotic string theories. We illustrate this by computing the one loop correction to the mass of the first massive state on the leading Regge trajectory in SO(32) heterotic st...
Effective Action of Scalar QED in Electric Field Backgrounds
Kim, Sang Pyo; Yoon, Yongsung
2008-01-01
We use the evolution operator method to find the one-loop effective action of scalar QED in electric field backgrounds in terms of the Bogoliubov coefficient between the ingoing and the outgoing vacuum. The effective action shows the general relation between the vacuum persistence and the mean number of created pairs for any electric field. We obtain the exact effective action for a constant electric field and a pulsed electric field, E_0 sech^2 (t/tau), and show that the imaginary part correctly yields the vacuum persistence.
N >= 4 Supergravity Amplitudes from Gauge Theory at One Loop
Bern, Z; Johansson, H
2011-01-01
We expose simple and practical relations between the integrated four- and five-point one-loop amplitudes of N >= 4 supergravity and the corresponding (super-)Yang-Mills amplitudes. The link between the amplitudes is simply understood using the recently uncovered duality between color and kinematics that leads to a double-copy structure for gravity. These examples provide additional direct confirmations of the duality and double-copy properties at loop level for a sample of different theories.
One-loop tensor Feynman integral reduction with signed minors
DEFF Research Database (Denmark)
Fleischer, Jochem; Riemann, Tord; Yundin, Valery
2012-01-01
We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in terms...... in a systematic way. The final expressions for the numerical evaluation are then compact combinations of the contributing basic scalar functions....
The elastic QCD dipole amplitude at one-loop
Navelet, H
1999-01-01
We derive the analytic expression of the two one-loop dipole contributions to the elastic 4-gluon amplitude in QCD. The first one corresponds to the double QCD pomeron exchange, the other to an order alpha^2 correction to one-pomeron exchange. Both are expressed in terms of the square of the recently derived triple QCD pomeron vertex and involve a summation over all conformal Eigenvectors of the BFKL kernel.
Symbols of one-loop integrals from mixed Tate motives
Spradlin, Marcus; Volovich, Anastasia
2011-11-01
We use a result on mixed Tate motives due to Goncharov [1] to show that the symbol of an arbitrary one-loop 2 m-gon integral in 2 m dimensions may be read off directly from its Feynman parameterization. The algorithm proceeds via recursion in m seeded by the well-known box integrals in four dimensions. As a simple application of this method we write down the symbol of a three-mass hexagon integral in six dimensions.
EW and QCD One-Loop Amplitudes with RECOLA
Actis, Stefano; Hofer, Lars; Scharf, Andreas; Uccirati, Sandro
2013-01-01
We present the computer code RECOLA for the computation of EW and QCD amplitudes in the Standard Model at next-to-leading order. One-loop amplitudes are represented as linear combinations of tensor integrals whose coefficients are calculated by means of recursive relations similar to Dyson-Schwinger equations. A novel treatment of colour enables us to recursively construct the colour structure of the amplitude efficiently. RECOLA is linked with the library COLLIER for the computation of the tensor integrals.
One-loop triple collinear splitting amplitudes in QCD
Badger, Simon; Peraro, Tiziano
2015-01-01
We study the factorisation properties of one-loop scattering amplitudes in the triple collinear limit and extract the universal splitting amplitudes for processes initiated by a gluon. The splitting amplitudes are derived from the analytic Higgs plus four partons amplitudes. We present compact results for primitive helicity splitting amplitudes making use of super-symmetric decompositions. The universality of the collinear factorisation is checked numerically against the full colour six parton squared matrix elements.
Kirpichnikov, D. V.
2013-01-01
We discuss the one loop effects of massless fermion fields on the low energy vector brane-to-brane propagators in the framework of two QED brane-world scenarios. We show that one loop photon brane-to-brane propagator has a power law pathologic IR divergences in the 5D QED brane-world model with gap between the vector zero mode and continuous states. We also find that bulk fermions do not give rise to IR divergences in a photon brane-to-brane Green's function at least at the one loop level in ...
One-loop corrections to the baryon axial vector current
Indian Academy of Sciences (India)
M A Hernández-Ruíz
2012-10-01
The symmetry breaking corrections to the pion–baryon couplings vanish to first order in $1/N_{c}$, where $N_{c}$ is the number of colours. Loop graphs with octet and decuplet intermediate states cancel to various orders in $N_{c}$ as a consequence of the large-$N_{c}$ spin-flavour symmetry of QCD baryons. The baryon axial vector current is computed at one-loop order in heavy baryon chiral perturbation theory in the large Nc limit. $1/N_{c}$ corrections in the case of $g_{A}$ in QCD are presented here.
One-loop corrections for Higgs-portal dark matter
Arroyo, J Armando
2016-01-01
Models endowed with Higgs portals can probe into the hidden sectors of particle physics while providing stable dark matter candidates. Previous tree-level computations in such scenarios have shown that experimental bounds constrain dark matter to a very narrow region in parameter space. Aiming at improving the study of the implications of those constraints, we inspect one-loop corrections to the annihilation cross section for scalar dark matter into observable fermions. We find that these loop contributions might be enough to drastically change those results by deforming in about 10% the allowed parameter space for dark matter particles with masses even below 1 TeV. These findings encourage further investigation.
Closed-Form Decomposition of One-Loop Massive Amplitudes
Britto, Ruth; Mastrolia, Pierpaolo
2008-01-01
We present formulas for the coefficients of 2-, 3-, 4- and 5-point master integrals for one-loop massive amplitudes. The coefficients are derived from unitarity cuts in D dimensions. The input parameters can be read off from any unitarity-cut integrand, as assembled from tree-level expressions, after simple algebraic manipulations. The formulas presented here are suitable for analytical as well as numerical evaluation. Their validity is confirmed in two known cases of helicity amplitudes contributing to gg -> gg and gg -> gH, where the masses of the Higgs and the fermion circulating in the loop are kept as free parameters.
One-loop kink mass shifts: a computational approach
Alonso-Izquierdo, Alberto
2011-01-01
In this paper we develop a procedure to compute the one-loop quantum correction to the kink masses in generic (1+1)-dimensional one-component scalar field theoretical models. The procedure uses the generalized zeta function regularization method helped by the Gilkey-de Witt asymptotic expansion of the heat function via Mellin's transform. We find a formula for the one-loop kink mass shift that depends only on the part of the energy density with no field derivatives, evaluated by means of a symbolic software algorithm that automates the computation. The improved algorithm with respect to earlier work in this subject has been tested in the sine-Gordon and $\\lambda(\\phi)_2^4$ models. The quantum corrections of the sG-soliton and $\\lambda(\\phi^4)_2$-kink masses have been estimated with a relative error of 0.00006% and 0.00007% respectively. Thereafter, the algorithm is applied to other models. In particular, an interesting one-parametric family of double sine-Gordon models interpolating between the ordinary sine-...
Bootstrapping One-Loop QCD Amplitudeswith General Helicities
Energy Technology Data Exchange (ETDEWEB)
Berger, Carola F.; Bern, Zvi; Dixon, Lance J.; Forde, Darren; Kosower, David A.
2006-04-25
The recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD combines the unitarity method with loop-level on-shell recursion. For generic helicity configurations, the recursion relations may involve undetermined contributions from non-standard complex singularities or from large values of the shift parameter. Here we develop a strategy for sidestepping difficulties through use of pairs of recursion relations. To illustrate the strategy, we present sets of recursion relations needed for obtaining n-gluon amplitudes in QCD. We give a recursive solution for the one-loop n-gluon QCD amplitudes with three or four color-adjacent gluons of negative helicity and the remaining ones of positive helicity. We provide an explicit analytic formula for the QCD amplitude A{sub 6;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}), as well as numerical results for A{sub 7;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}), A{sub 8;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}, 8{sup +}), and A{sub 8;1}(1{sup -}, 2{sup -}, 3{sup -}, 4{sup -}, 5{sup +}, 6{sup +}, 7{sup +}, 8{sup +}). We expect the on-shell bootstrap approach to have widespread applications to phenomenological studies at colliders.
One-loop renormalization of a gravity-scalar system
Energy Technology Data Exchange (ETDEWEB)
Park, I.Y. [Philander Smith College, Department of Applied Mathematics, Little Rock, AR (United States)
2017-05-15
Extending the renormalizability proposal of the physical sector of 4D Einstein gravity, we have recently proposed renormalizability of the 3D physical sector of gravity-matter systems. The main goal of the present work is to conduct systematic one-loop renormalization of a gravity-matter system by applying our foliation-based quantization scheme. In this work we explicitly carry out renormalization of a gravity-scalar system with a Higgs-type potential. With the fluctuation part of the scalar field gauged away, the system becomes renormalizable through a metric field redefinition. We use dimensional regularization throughout. One of the salient aspects of our analysis is how the graviton propagator acquires the ''mass'' term. One-loop calculations lead to renormalization of the cosmological and Newton constants. We discuss other implications of our results as well: time-varying vacuum energy density and masses of the elementary particles as well as the potential relevance of Neumann boundary condition for black hole information. (orig.)
On the one-loop corrections to inflation II: The consistency relation
Energy Technology Data Exchange (ETDEWEB)
Sloth, Martin S. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)]. E-mail: sloth@phys.au.dk
2007-07-16
In this paper we extend our previous treatment of the one-loop corrections to inflation. Previously we calculated the one-loop corrections to the background and the two-point correlation function of inflaton fluctuations in a specific model of chaotic inflation. We showed that the loop corrections depend on the total number of e-foldings and estimated that the effect could be as large as a few percent in a {lambda}{phi}{sup 4} model of chaotic inflation. In the present paper we generalize the calculations to general inflationary potentials. We find that effect can be as large as 70% in the simplest model of chaotic inflation with a quadratic m{sup 2}{phi}{sup 2} inflationary potential. We discuss the physical interpretation of the effect in terms of the tensor-to-scalar consistency relation. Finally, we discuss the relation to the work of Weinberg on quantum contributions to cosmological correlators.
On the One Loop Corrections to Inflation II: The Consistency Relation
Sloth, M S
2006-01-01
In this paper we extend our previous treatment of the one-loop corrections to inflation. Previously we calculated the one-loop corrections to the background and the two-point correlation function of inflaton fluctuations in a specific model of chaotic inflation. We showed that the loop corrections depend on the total number of e-foldings and estimated that the effect could be as large as a few percent in a lambda-phi-four model of chaotic inflation. In the present paper we generalize the calculations to general inflationary potentials. We find that effect can be as large as 35% in the simplest model of chaotic inflation with a quadratic inflationary potential. We discuss the physical interpretation of the effect in terms of the tensor-to-scalar consistency relation. Finally, we discuss the relation to the work of Weinberg on quantum contributions to cosmological correlators.
Direct Extraction of One-loop Integral Coefficients
Energy Technology Data Exchange (ETDEWEB)
Forde, Darren
2007-04-16
We present a general procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted by considering two-particle and triple unitarity cuts of the corresponding bubble and triangle integral functions. After choosing a specific parameterization of the cut loop momentum we can uniquely identify the coefficients of the desired integral functions simply by examining the behavior of the cut integrand as the unconstrained parameters of the cut loop momentum approach infinity. In this way we can produce compact forms for scalar integral coefficients. Applications of this method are presented for both QCD and electroweak processes, including an alternative form for the recently computed three-mass triangle coefficient in the six-photon amplitude A{sub 6}(1{sup -}, 2{sup +}, 3{sup -}, 4{sup +}, 5{sup -}, 6{sup +}). The direct nature of this extraction procedure allows for a very straightforward automation of the procedure.
One-loop spectroscopy of semiclassically quantized strings: bosonic sector
Forini, V; Pawellek, M; Vescovi, E
2014-01-01
We make a further step in the analytically exact quantization of spinning string states in semiclassical approximation, by evaluating the exact one-loop partition function for a class of two-spin string solutions for which quadratic fluctuations form a non-trivial system of coupled modes. This is the case of a folded string in the $SU(2)$ sector, in the limit described by a quantum Landau-Lifshitz model. The same applies to the full bosonic sector of fluctuations over the folded spinning string in $AdS_5$ with an angular momentum $J$ in $S^5$. Fluctuations are governed by a special class of fourth-order differential operators, with coefficients being meromorphic functions on the torus, which we are able to solve exactly.
A differential operator for integrating one-loop scattering equations
Chen, Gang; Wang, Tianheng; Xu, Feng
2016-01-01
We propose a differential operator for computing the residues associated with a class of meromorphic $n$-forms that frequently appear in the Cachazo-He-Yuan form of the scattering amplitudes. This differential operator is conjectured to be uniquely determined by the local duality theorem and the intersection number of the divisors in the $n$-form. We use the operator to evaluate the tree-level amplitude of $\\phi^3$ theory and the one-loop integrand of Yang-Mills theory from their CHY forms. The method can reduce the complexity of the calculation. In addition, the expression for the 1-loop four-point Yang-Mills integrand obtained in our approach has a clear correspondence with the Q-cut results.
One-loop renormalization of quantum electrodynamics in curved spacetime
Panangaden, Prakash
1981-04-01
In this paper we discuss the renormalizability of quantum electrodynamics (QED) in a general curved spacetime. A generating functional is introduced and position-space Feynman rules are obtained. Functional techniques are used to show that a form of Ward's identity can be derived in curved spacetime. A local momentum representation for the scalar and vector propagators is introduced. The one-loop diagrams for the electron and photon self-energy are computed and it is shown that there are no divergences that are not present in flat space. It is shown that this latter result depends crucially on the gauge invariance of the theory and is not merely a trivial consequence of renormalizability of QED in flat spacetime.
One-loop structure of the U(1) gauge model on the truncated Heisenberg space
Burić, Maja; Nenadović, Luka; Prekrat, Dragan
2016-12-01
We calculate divergent one-loop corrections to the propagators of the U(1) gauge theory on the truncated Heisenberg space, which is one of the extensions of the Grosse-Wulkenhaar model. The model is purely geometric, based on the Yang-Mills action; the corresponding gauge-fixed theory is BRST invariant. We quantize perturbatively and, along with the usual wave-function and mass renormalizations, we find divergent nonlocal terms of the Box ^{-1} and Box ^{-2} type. We discuss the meaning of these terms and possible improvements of the model.
Radiative corrections to the non commutative photon propagator at one-loop order
Energy Technology Data Exchange (ETDEWEB)
Boutalbi, E.; Kouadik, S. [Laboratory of Particle Physics and Statistical Physics, Ecole Normale Superieure BP 92 Vieux kouba (Algeria); Faculty of Technologies Sciences,University of Medea (Algeria)
2012-06-27
We study the non-commutative gauge theory on the Moyal space. We add the harmonic potential introduced by Grosse and Wulkenhaar to the Maxwell Lagrange as well as the Gauge fixation. We determine the non-commutative U{sub *}(1) Gauge action which is invariant under the BRST transformations in the matrix basis. We determine in this basis the quadratic parts and the vertex of the Gauge field A{sub {mu}} and of the Faddeev-Popov ghost fields c(bar sign)andc. Finally, we study the perturbative correction to one loop order of the one point function in the matrix basis.
One-loop structure of the U(1) gauge model on the truncated Heisenberg space
Burić, Maja; Prekrat, Dragan
2016-01-01
We calculate divergent one-loop corrections to the propagators of the U(1) gauge theory on the truncated Heisenberg space, which is one of the extensions of the Grosse-Wulkenhaar model. The model is purely geometric, based on the Yang-Mills action; the corresponding gauge-fixed theory is BRST invariant. We quantize perturbatively and, along with the usual wave-function and mass renormalizations, we find divergent nonlocal terms of the $\\Box^{-1}$ and $\\Box^{-2}$ type. We discuss the meaning of these terms and possible improvements of the model.
A Mathematica package for calculation of one-loop penguins in FCNC processes
Bednyakov, Alexander Vadimovich; Tanyıldızı, Şükrü Hanif
2015-09-01
In this work, we present a Mathematica package Peng4BSM@LO which calculates the contributions to the Wilson Coefficients of certain effective operators originating from the one-loop penguin Feynman diagrams. Both vector and scalar external legs are considered. The key feature of our package is the ability to find the corresponding expressions in almost any New Physics model which extends the SM and has no flavor changing neutral current (FCNC) transitions at the tree level.
On the low-energy limit of one-loop photon-graviton amplitudes
Energy Technology Data Exchange (ETDEWEB)
Bastianelli, F. [Dipartimento di Fisica, Universita di Bologna and INFN Sezione di Bologna, Via Irnerio 46, I-40126 Bologna (Italy); Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Muehlenberg 1, D-14476 Potsdam (Germany); Corradini, O. [Centro de Estudios en Fisica y Matematicas Basicas y Aplicadas, Universidad Autonoma de Chiapas, C.P. 29000, Tuxtla Gutierrez (Mexico); Davila, J.M. [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C-3, Apdo. Postal 2-82, C.P. 58040, Morelia, Michoacan (Mexico); Schubert, C., E-mail: schubert@ifm.umich.mx [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Muehlenberg 1, D-14476 Potsdam (Germany); Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C-3, Apdo. Postal 2-82, C.P. 58040, Morelia, Michoacan (Mexico)
2012-09-19
We present first results of a systematic study of the structure of the low-energy limit of the one-loop photon-graviton amplitudes induced by massive scalars and spinors. Our main objective is the search of KLT-type relations where effectively two photons merge into a graviton. We find such a relation at the graviton-photon-photon level. We also derive the diffeomorphism Ward identity for the 1PI one-graviton-N-photon amplitudes.
The $Z$ decay width in the SMEFT: $y_t$ and $\\lambda$ corrections at one loop
Hartmann, Christine; Trott, Michael
2016-01-01
We calculate one loop $y_t$ and $\\lambda$ dependent corrections to $\\bar{\\Gamma}_Z,\\bar{R}_f^0$ and the partial $Z$ widths due to dimension six operators in the Standard Model Effective Field Theory (SMEFT), including finite terms. We assume $\\rm CP$ symmetry and a $\\rm U(3)^5$ symmetry in the UV matching onto the dimension six operators, dominantly broken by the Standard Model Yukawa matrices. Corrections to these observables are predicted using the input parameters $\\{\\hat{\\alpha}_{ew}, \\hat{M}_Z, \\hat{G}_F, \\hat{m}_t, \\hat{m}_h\\}$ extracted with one loop corrections in the same limit. We show that at one loop the number of SMEFT parameters contributing to the precise LEPI pseudo-observables exceeds the number of measurements. As a result the SMEFT parameters contributing to LEP data are formally unbounded when the size of loop corrections are reached until other data is considered in a global analysis. The size of these loop effects is generically a correction of order $\\sim\\%$ to leading effects in the SM...
Three-Point Functions of Twist-Two Operators in N=4 SYM at One Loop
Plefka, Jan
2012-01-01
We calculate three-point functions of two protected operators and one twist-two operator with arbitrary even spin j in N=4 SYM theory to one-loop order. In order to carry out the calculations we project the indices of the spin j operator to the light-cone and evaluate the correlator in a soft-limit where the momentum coming in at the spin j operator becomes zero. This limit largely simplifies the perturbative calculation, since all three-point diagrams effectively reduce to two-point diagrams and the dependence on the one-loop mixing matrix drops out completely. The results of our direct calculation are in agreement with the structure constants obtained by F.A. Dolan and H. Osborn from the operator product expansion of four-point functions of half-BPS operators.
One-loop anomaly mediated scalar masses and (g - 2){sub μ} in pure gravity mediation
Energy Technology Data Exchange (ETDEWEB)
Evans, Jason L.; Olive, Keith A. [University of Minnesota, School of Physics and Astronomy, William I. Fine Theoretical Physics Institute, Minneapolis, MN (United States); Ibe, Masahiro [ICRR, University of Tokyo, Kashiwa (Japan); University of Tokyo, Kavli IPMU (WPI), TODIAS, Kashiwa (Japan); Yanagida, Tsutomu T. [University of Tokyo, Kavli IPMU (WPI), TODIAS, Kashiwa (Japan)
2014-02-15
We consider the effects of non-universalities among sfermion generations in models of PureGravity Mediation (PGM). In PGM models and in many models with strongly stabilized moduli, the gravitino mass may be O(100) TeV, whereas gaugino masses, generated through anomalies at one loop, remain relatively light O(1) TeV. In models with scalar mass universality, input scalar masses are generally very heavy (m{sub 0} ≅ m{sub 3/2}), resulting in a mass spectrum resembling that in split supersymmetry. However, if one adopts a no-scale or partial no-scale structure for theKahler manifold, sfermion masses may vanish at the tree level. It is usually assumed that the leading order anomaly mediated contribution to scalar masses appears at two loops. However, there are at least two possible sources for one-loop scalar masses. These may arise if Pauli.Villars fields are introduced as messengers of supersymmetry breaking. We consider the consequences of a spectrum in which the scalar masses associated with the third generation are heavy (order m{sub 3/2}) with one-loop scalar masses for the first two generations. A similar spectrum is expected to arise in GUT models based on E{sub 7}/SO(10) where the first two generations of scalars act as pseudo-Nambu-Goldstone bosons. Explicit breaking of this symmetry by the gauge couplings then generates one-loop masses for the first two generations. In particular, we show that it may be possible to reconcile the g{sub μ} - 2 discrepancy with potentially observable scalars and gauginos at the LHC. (orig.)
One-loop tensor Feynman integral reduction with signed minors
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Yundin, V. [Copenhagen Univ. (Denmark). Niels Bohr International Academy and Discovery Center
2011-12-15
We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in terms of a basis of scalar integrals, which is provided by an external library, e.g. QCDLoop. We shortly describe installation and use of PJFry. Examples for numerical results are shown, including a special treatment for small or vanishing inverse four-point Gram determinants. An extremely efficient application of the formalism is the immediate evaluation of complete contractions of the tensor integrals with external momenta. This leads to the problem of evaluating sums over products of signed minors with scalar products of chords. Chords are differences of external momenta. These sums may be evaluated analytically in a systematic way. The final expressions for the numerical evaluation are then compact combinations of the contributing basic scalar functions. (orig.)
One-loop corrections from higher dimensional tree amplitudes
Cachazo, Freddy; He, Song; Yuan, Ellis Ye
2016-08-01
We show how one-loop corrections to scattering amplitudes of scalars and gauge bosons can be obtained from tree amplitudes in one higher dimension. Starting with a complete tree-level scattering amplitude of n + 2 particles in five dimensions, one assumes that two of them cannot be "detected" and therefore an integration over their LIPS is carried out. The resulting object, function of the remaining n particles, is taken to be four-dimensional by restricting the corresponding momenta. We perform this procedure in the context of the tree-level CHY formulation of amplitudes. The scattering equations obtained in the procedure coincide with those derived by Geyer et al. from ambitwistor constructions and recently studied by two of the authors for bi-adjoint scalars. They have two sectors of solutions: regular and singular. We prove that the contribution from regular solutions generically gives rise to unphysical poles. However, using a BCFW argument we prove that the unphysical contributions are always homogeneous functions of the loop momentum and can be discarded. We also show that the contribution from singular solutions turns out to be homogeneous as well.
One-Loop Corrections from Higher Dimensional Tree Amplitudes
Cachazo, Freddy; Yuan, Ellis Ye
2015-01-01
We show how one-loop corrections to scattering amplitudes of scalars and gauge bosons can be obtained from tree amplitudes in one higher dimension. Starting with a complete tree-level scattering amplitude of n+2 particles in five dimensions, one assumes that two of them cannot be "detected" and therefore an integration over their LIPS is carried out. The resulting object, function of the remaining n particles, is taken to be four-dimensional by restricting the corresponding momenta. We perform this procedure in the context of the tree-level CHY formulation of amplitudes. The scattering equations obtained in the procedure coincide with those derived by Geyer et al from ambitwistor constructions and recently studied by two of the authors for bi-adjoint scalars. They have two sectors of solutions: regular and singular. We prove that the contribution from regular solutions generically gives rise to unphysical poles. However, using a BCFW argument we prove that the unphysical contributions are always homogeneous f...
Three-dimensional noncommutative Yukawa theory: Induced effective action and propagating modes
Bufalo, R
2016-01-01
In this paper, we establish the analysis of noncommutative Yukawa theory, encompassing neutral and charged scalar fields. We approach the analysis by considering carefully the derivation of the respective effective actions. Hence, based on the obtained results, we compute the one-loop contributions to the neutral and charged scalar field self-energy, as well as to the Chern-Simons polarization tensor. In order to properly define the behaviour of the quantum fields, the known UV/IR mixing due to radiative corrections is analysed in the one-loop physical dispersion relation of the scalar and gauge fields.
Ninja: Automated Integrand Reduction via Laurent Expansion for One-Loop Amplitudes
Peraro, Tiziano
2014-01-01
We present the public C++ library Ninja, which implements the Integrand Reduction via Laurent Expansion method for the computation of one-loop integrals. The algorithm is suited for applications to complex one-loop processes.
One-loop stabilization of the fuzzy four-sphere via softly broken SUSY
Steinacker, Harold C
2015-01-01
We describe a stabilization mechanism for fuzzy $S^4_N$ in the Euclidean IIB matrix model in the presence of a positive mass term. The one-loop effective potential for the radius contains an attractive contribution attributed to supergravity, while the mass term induces a repulsive contribution for small radius due to SUSY breaking. This leads to a stabilization of the radius. The mechanism should be pertinent to recent results on the genesis of 3+1-dimensional space-time in the Minkowskian IIB model.
One-loop stabilization of the fuzzy four-sphere via softly broken SUSY
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C. [Faculty of Physics, University of Vienna,Boltzmanngasse 5, A-1090 Vienna (Austria)
2015-12-17
We describe a stabilization mechanism for fuzzy S{sub N}{sup 4} in the Euclidean IIB matrix model due to vacuum energy in the presence of a positive mass term. The one-loop effective potential for the radius contains an attractive contribution attributed to supergravity, while the mass term induces a repulsive contribution for small radius due to SUSY breaking. This leads to a stabilization of the radius. The mechanism should be pertinent to recent results on the genesis of 3+1-dimensional space-time in the Minkowskian IIB model.
Kirpichnikov, D. V.
2013-12-01
We discuss the one-loop effects of massless fermion fields on the low energy vector brane-to-brane propagators in the framework of two QED brane-world scenarios. We show that the one-loop photon brane-to-brane propagator has a power-law pathologic IR divergence in the five-dimensional QED brane-world model with a mass gap between the vector zero mode and continuous states. We also find that bulk fermions do not give rise to IR divergences in a photon brane-to-brane Green’s function, at least at the one-loop level in the framework of a six-dimensional QED brane model with a gapless mass spectrum between vector zero mode and higher states.
Kirpichnikov, D V
2013-01-01
We discuss the one loop effects of massless fermion fields on the low energy vector brane-to-brane propagators in the framework of two QED brane-world scenarios. We show that one loop photon brane-to-brane propagator has a power law pathologic IR divergences in the 5D QED brane-world model with gap between the vector zero mode and continuous states. We also find that bulk fermions do not give rise to IR divergences in a photon brane-to-brane Green's function at least at the one loop level in the framework of 6D QED brane model with gapless mass spectrum between vector zero mode and higher states.
A one-loop test for construction of 4D N=4 SYM from 2D SYM via fuzzy sphere geometry
Matsuura, So
2015-01-01
As a perturbative check of the construction of four-dimensional (4D) ${\\cal N}=4$ supersymmetric Yang-Mills theory (SYM) from mass deformed ${\\cal N}=(8,8)$ SYM on the two-dimensional (2D) lattice, the one-loop effective action for scalar kinetic terms is computed in ${\\cal N}=4$ $U(k)$ SYM on ${\\mathbb R}^2 \\times$ (fuzzy $S^2$), which is obtained by expanding 2D ${\\cal N}=(8,8)$ $U(N)$ SYM with mass deformation around its fuzzy sphere classical solution. The radius of the fuzzy sphere is proportional to the inverse of the mass. We consider the two successive limits; (1) decompactify the fuzzy sphere to a noncommutative (Moyal) plane and (2) turn off the noncommutativity of the Moyal plane. It is clear at the classical level to obtain the ordinary ${\\cal N}=4$ SYM on ${\\mathbb R}^4$ in the limits, while it is nontrivial at the quantum level. The one-loop effective action for $SU(k)$ sector of the gauge group $U(k)$ coincides with that of the ordinary 4D ${\\cal N}=4$ SYM in the above limits. Although "noncomm...
One-loop corrections, uncertainties and approximations in neutralino annihilations: Examples
Boudjema, Fawzi; Kulkarni, Suchita
2011-01-01
The extracted value of the relic density has reached the few per-cent level precision. One can therefore no longer content oneself with calculations of this observable where the annihilation processes are computed at tree-level, especially in supersymmetry where radiative corrections are usually large. Implementing full one-loop corrections to all annihilation processes that would be needed in a scan over parameters is a daunting task. On the other hand one may ask whether the bulk of the corrections are taken into account through effective couplings of the neutralino that improve the tree-level calculation and would be easy to implement. We address this issue by concentrating in this first study on the neutralino coupling to i) fermions and sfermions and ii) Z. After constructing the effective couplings we compare their efficiency compared to the full one-loop calculation and comment on the failures and success of the approach. As a bonus we point out that large non decoupling effects of heavy sfermions coul...
One-loop pseudo-Goldstone masses in the minimal S O (10 ) Higgs model
Gráf, Lukáš; Malinský, Michal; Mede, Timon; Susič, Vasja
2017-04-01
We calculate the prominent perturbative contributions shaping the one-loop scalar spectrum of the minimal renormalizable nonsupersymmetric S O (10 ) Higgs model whose unified gauge symmetry is spontaneously broken by an adjoint scalar. Focusing on its potentially realistic 45 ⊕126 variant in which the rank is reduced by a vacuum expectation value of the 5-index antisymmetric self-dual tensor, we provide a thorough analysis of the corresponding Coleman-Weinberg one-loop effective potential, paying particular attention to the masses of the potentially tachyonic pseudo-Goldstone bosons transforming as (1, 3, 0) and (8, 1, 0) under the standard model (SM) gauge group. The results confirm the assumed existence of extended regions in the parameter space supporting a locally stable SM-like quantum vacuum inaccessible at the tree level. The effective potential tedium is compared to that encountered in the previously studied 45 ⊕16 S O (10 ) Higgs model where the polynomial corrections to the relevant pseudo-Goldstone masses turn out to be easily calculable within a very simplified purely diagrammatic approach.
One-loop pseudo-Goldstone masses in the minimal $SO(10)$ Higgs model
Gráf, Lukáš; Mede, Timon; Susič, Vasja
2016-01-01
We calculate the prominent perturbative contributions shaping the one-loop scalar spectrum of the minimal non-supersymmetric renormalizable $SO(10)$ Higgs model whose unified gauge symmetry is spontaneously broken by an adjoint scalar. Focusing on its potentially realistic $45\\oplus 126$ variant in which the rank is reduced by a VEV of the 5-index self-dual antisymmetric tensor, we provide a thorough analysis of the corresponding one-loop Coleman-Weinberg potential, paying particular attention to the masses of the potentially tachyonic pseudo-Goldstone bosons (PGBs) transforming as $(8,1,0)$ and $(1,3,0)$ under the Standard Model gauge group. The results confirm the assumed existence of extended regions in the parameter space supporting a locally stable SM-like quantum vacuum inaccessible at the tree-level. The effective potential (EP) tedium is compared to that encountered in the previously studied $45\\oplus 16$ $SO(10)$ Higgs model where the polynomial corrections to the relevant pseudo-Goldstone masses tur...
Partial Supergravity Breaking and the Effective Action of Consistent Truncations
Grimm, Thomas W; Lust, Severin
2014-01-01
We study vacua of N = 4 half-maximal gauged supergravity in five dimensions and determine crucial properties of the effective theory around the vacuum. The main focus is on configurations with exactly two broken supersymmetries, since they frequently appear in consistent truncations of string theory and supergravity. Evaluating one-loop corrections to the Chern-Simons terms we find necessary conditions to ensure that a consistent truncation also gives rise to a proper effective action of an underlying more fundamental theory. To obtain concrete examples, we determine the N=4 action of M-theory on six-dimensional SU(2)-structure manifolds with background fluxes. Calabi-Yau threefolds with vanishing Euler number are examples of SU(2)-structure manifolds that yield N=2 Minkowski vacua. We find that that one-loop corrections to the Chern-Simons terms vanish trivially and thus do not impose constraints on identifying effective theories. This result is traced back to the absence of isometries on these geometries. E...
Computing the effective action with the functional renormalization group
Energy Technology Data Exchange (ETDEWEB)
Codello, Alessandro [CP3-Origins and the Danish IAS University of Southern Denmark, Odense (Denmark); Percacci, Roberto [SISSA, Trieste (Italy); INFN, Sezione di Trieste, Trieste (Italy); Rachwal, Leslaw [Fudan University, Department of Physics, Center for Field Theory and Particle Physics, Shanghai (China); Tonero, Alberto [ICTP-SAIFR and IFT, Sao Paulo (Brazil)
2016-04-15
The ''exact'' or ''functional'' renormalization group equation describes the renormalization group flow of the effective average action Γ{sub k}. The ordinary effective action Γ{sub 0} can be obtained by integrating the flow equation from an ultraviolet scale k = Λ down to k = 0. We give several examples of such calculations at one-loop, both in renormalizable and in effective field theories. We reproduce the four-point scattering amplitude in the case of a real scalar field theory with quartic potential and in the case of the pion chiral Lagrangian. In the case of gauge theories, we reproduce the vacuum polarization of QED and of Yang-Mills theory. We also compute the two-point functions for scalars and gravitons in the effective field theory of scalar fields minimally coupled to gravity. (orig.)
On resumming inflationary perturbations beyond one-loop
DEFF Research Database (Denmark)
Riotto, Antonio; Sloth, Martin Snoager
2008-01-01
It is well known that the correlation functions of a scalar field in a quasi-de Sitter space exhibit at the loop level cumulative infra-red effects proportional to the total number of e-foldings of inflation. Using the in-in formalism, we explore the behavior of these infra-red effects in the large...
One-loop divergences in chiral perturbation theory and right-invariant metrics on SU(3)
Energy Technology Data Exchange (ETDEWEB)
Esposito-Farese, G. (Centre National de la Recherche Scientifique, 13 - Marseille (France). Centre de Physique Theorique)
1991-04-01
In the framework of chiral perturbation theory, we compute the one-loop divergences of the effective Lagrangian describing strong and non-leptonic weak interactions of pseudoscalar mesons. We use the background field method and the heat-kernel expansion, and underline the geometrical meaning of the different terms, showing how the right-invariance of the metrics on SU(3) allows to clarify and simplify the calculations. Our results are given in terms of a minimal set of independent counterterms, and shorten previous ones of the literature, in the particular case where the electromagnetic field is the only external source which is considered. We also show that a geometrical construction of the effective Lagrangian at order O(p{sup 4}) allows to derive some relations between the finite parts of the coupling constants. These relations do not depend on the scale {mu} used to renormalize. (orig.).
On Resumming Inflationary Perturbations beyond One-loop
Riotto, Antonio
2008-01-01
It is well known that the correlation functions of a scalar field in a quasi-de Sitter space exhibit at the loop level cumulative infra-red effects proportional to the total number of e-foldings of inflation. Using the in-in formalism, we explore the behavior of these infra-red effects in the large N limit of an O(N) invariant scalar field theory with quartic self-interactions. By resumming all higher-order loop diagrams non-perturbatively, we show that the infra-red effects disappear and that the connected four-point correlation function, which is a signal of non-Gaussianity, is non-perturbatively enhanced with respect to its tree-level value.
On resumming inflationary perturbations beyond one-loop
Energy Technology Data Exchange (ETDEWEB)
Riotto, Antonio [CERN, Theory Division, Geneve 23, CH-1211 (Switzerland); Sloth, Martin S, E-mail: antonio.riotto@cern.ch, E-mail: sloth@phys.au.dk [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)
2008-04-15
It is well known that the correlation functions of a scalar field in a quasi-de Sitter space exhibit at the loop level cumulative infrared effects proportional to the total number of e-foldings of inflation. Using the in-in formalism, we explore the behavior of these infrared effects in the large N limit of an O(N)-invariant scalar field theory with quartic self-interactions. By resumming all higher-order loop diagrams non-perturbatively, we show that the connected four-point correlation function, which is a signal of non-Gaussianity, is non-perturbatively enhanced with respect to its tree-level value.
One-Loop Gauge Theory Amplitudes in N=4 Super Yang-Mills from MHV Vertices
Brandhuber, A; Travaglini, G; Brandhuber, Andreas; Spence, Bill; Travaglini, Gabriele
2004-01-01
We propose a new, twistor string theory inspired formalism to calculate loop amplitudes in N=4 super Yang-Mills theory. In this approach, maximal helicity violating (MHV) tree amplitudes of N=4 super Yang-Mills are used as vertices, using an off-shell prescription introduced by Cachazo, Svrcek and Witten, and combined into effective diagrams that incorporate large numbers of conventional Feynman diagrams. As an example, we apply this formalism to the particular class of MHV one-loop scattering amplitudes with an arbitrary number of external legs in N=4 super Yang-Mills. Remarkably, our approach naturally leads to a representation of the amplitudes as dispersion integrals, which we evaluate exactly. Our results for the MHV amplitudes are in precise agreement with the expressions for this class of amplitudes obtained previously by Bern, Dixon, Dunbar and Kosower using the cut-constructibility approach.
One-Loop Partition Functions in Deformed $\\mathcal{N}=4$ SYM Theory
Fokken, Jan
2014-01-01
We study the thermodynamic behaviour of the real $\\beta$- and $\\gamma_i$-deformation of $\\mathcal{N}=4$ Super Yang-Mills theory on $\\mathbb{R}\\times S^3$ in the planar limit. These theories were shown to be the most general asymptotically integrable supersymmetric and non-supersymmetric field-theory deformations of $\\mathcal{N}=4$ Super Yang-Mills theory, respectively. We calculate the first loop correction to their partition functions using an extension of the dilatation-operator and P\\'{o}lya-counting approach. In particular, we account for the one-loop finite-size effects which occur for operators of length one and two. Remarkably, we find that the $\\mathcal{O}(\\lambda)$ correction to the Hagedorn temperature is independent of the deformation parameters, although the partition function depends on them in a non-trivial way.
Impacts of biasing schemes in the one-loop integrated perturbation theory
Matsubara, Takahiko; Desjacques, Vincent
2016-06-01
The impact of biasing schemes on the clustering of tracers of the large-scale structure is analytically studied in the weakly nonlinear regime. For this purpose, we use the one-loop approximation of the integrated perturbation theory together with the renormalized bias functions of various, physically motivated Lagrangian bias schemes. These include the halo, peaks, and excursion set peaks model, for which we derive useful formulas for the evaluation of their renormalized bias functions. The shapes of the power spectra and correlation functions are affected by the different bias models at the level of a few percent on weakly nonlinear scales. These effects are studied quantitatively both in real and redshift space. The amplitude of the scale-dependent bias in the presence of primordial non-Gaussianity also depends on the details of the bias models. If left unaccounted for, these theoretical uncertainties could affect the robustness of the cosmological constraints extracted from galaxy clustering data.
Gauge theory one-loop amplitudes and the Britto-Cachazo-Feng-Witten recursion relations
Kharel, Savan; Siopsis, George
2012-07-01
We calculate gauge theory one-loop amplitudes with the aid of the complex shift used in the Britto-Cachazo-Feng-Witten (BCFW) recursion relations of tree amplitudes. We apply the shift to the integrand and show that the contribution from the limit of infinite shift vanishes after integrating over the loop momentum, with a judicious choice of basis for polarization vectors. This enables us to write the one-loop amplitude in terms of on shell tree and lower-point one-loop amplitudes. Some of the tree amplitudes are forward amplitudes. We show that their potential singularities do not contribute and the BCFW recursion relations can be applied in such a way as to avoid these singularities altogether. We calculate in detail n-point one-loop amplitudes for n=2, 3, 4, and outline the generalization of our method to n>4.
Dual-color decompositions at one-loop level in Yang-Mills theory
Du, Yi-Jian; Fu, Chih-Hao
2014-01-01
In this work, we extend the construction of dual color decomposition in Yang-Mills theory to one-loop level, i.e., we show how to write one-loop integrands in Yang-Mills theory to the dual DDM-form and the dual trace-form. In dual forms, integrands are decomposed in terms of color-ordered one-loop integrands for color scalar theory with proper dual color coefficients.In dual DDM decomposition, The dual color coefficients can be obtained directly from BCJ-form by applying Jacobi-like identities for kinematic factors. In dual trace decomposition, the dual trace factors can be obtained by imposing one-loop KK relations, reflection relation and their relation with the kinematic factors in dual DDM-form.
Structure constants of planar N =4 Yang Mills at one loop
Alday, L F; Gava, E; Narain, K S; Alday, Luis F.; David, Justin R.; Gava, Edi
2005-01-01
We study structure constants of gauge invariant operators in planar N=4 Yang-Mills at one loop with the motivation of determining features of the string dual of weak coupling Yang-Mills. We derive a simple renormalization group invariant formula characterizing the corrections to structure constants of any primary operator in the planar limit. Applying this to the scalar SO(6) sector we find that the one loop corrections to structure constants of gauge invariant operators is determined by the one loop anomalous dimension Hamiltonian in this sector. We then evaluate the one loop corrections to structure constants for scalars with arbitrary number of derivatives in a given holomorphic direction. We find that the corrections can be characterized by suitable derivatives on the four point tree function of a massless scalar with quartic coupling. We show that individual diagrams violating conformal invariance can be combined together to restore it using a linear inhomogeneous partial differential equation satisfied ...
Infrared behaviour of the one-loop scattering equations and supergravity integrands
Casali, Eduardo
2014-01-01
The recently introduced ambitwistor string led to a striking proposal for one-loop maximal supergravity amplitudes, localised on the solutions of the ambitwistor one-loop scattering equations. However, these amplitudes have not yet been explicitly analysed due to the apparent complexity of the equations that determine the localisation. In this paper we propose an analytic solution to the four-point one-loop scattering equations in the infrared (IR) regime of the amplitude. Using this solution, we compute the ambitwistor integrand and demonstrate that it correctly reproduces the four-graviton integrand, in the IR regime. This solution qualitatively extends to n points. To conclude, we explain that the ambitwistor one-loop scattering equations actually correspond to the standard Gross & Mende saddle point.
One-loop gauge theory amplitudes with an arbitrary number of external legs
Energy Technology Data Exchange (ETDEWEB)
Bern, Z.; Dunbar, D.C. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics; Dixon, L. [Stanford Univ., CA (United States). Stanford Linear Accelerator Center; Kosower, D.A. [Centre d`Etudes de Saclay, Gif-sur-Yvette (France). Service de Physique Theorique de Saclay
1994-05-01
The authors review recent progress in calculations of one-loop QCD amplitudes. By imposing the consistency requirements of unitarity and correct behavior as the momenta of two legs become collinear, they construct ansaetze for one-loop amplitudes with an arbitrary number of external legs. For supersymmetric amplitudes, which can be thought of as components of QCD amplitudes, the cuts uniquely specify the amplitude.
Effective Action of Softly Broken Supersymmetric Theories
Nibbelink, S G; Nibbelink, Stefan Groot; Nyawelo, Tino S.
2007-01-01
We study the renormalization of (softly) broken supersymmetric theories at the one loop level in detail. We perform this analysis in a superspace approach in which the supersymmetry breaking interactions are parameterized using spurion insertions. We comment on the uniqueness of this parameterization. We compute the one loop renormalization of such theories by calculating superspace vacuum graphs with multiple spurion insertions. To preform this computation efficiently we develop algebraic properties of spurion operators, that naturally arise because the spurions are often surrounded by superspace projection operators. Our results are general apart from the restrictions that higher super covariant derivative terms and some finite effects due to non-commutativity of superfield dependent mass matrices are ignored. One of the soft potentials induces renormalization of the Kaehler potential.
Computing the effective action with the functional renormalization group
DEFF Research Database (Denmark)
Codello, Alessandro; Percacci, Roberto; Rachwał, Lesław
2016-01-01
The “exact” or “functional” renormalization group equation describes the renormalization group flow of the effective average action Γ k. The ordinary effective action Γ 0 can be obtained by integrating the flow equation from an ultraviolet scale k= Λ down to k= 0. We give several examples of such...... of QED and of Yang–Mills theory. We also compute the two-point functions for scalars and gravitons in the effective field theory of scalar fields minimally coupled to gravity.......The “exact” or “functional” renormalization group equation describes the renormalization group flow of the effective average action Γ k. The ordinary effective action Γ 0 can be obtained by integrating the flow equation from an ultraviolet scale k= Λ down to k= 0. We give several examples...... of such calculations at one-loop, both in renormalizable and in effective field theories. We reproduce the four-point scattering amplitude in the case of a real scalar field theory with quartic potential and in the case of the pion chiral Lagrangian. In the case of gauge theories, we reproduce the vacuum polarization...
Systematic study of the d=5 Weinberg operator at one-loop order
Bonnet, Florian; Ota, Toshihiko; Winter, Walter
2012-01-01
We perform a systematic study of the $d=5$ Weinberg operator at the one-loop level. We identify three different categories of neutrino mass generation: (1) finite irreducible diagrams; (2) finite extensions of the usual seesaw mechanisms at one-loop and (3) divergent loop realizations of the seesaws. All radiative one-loop neutrino mass models must fall into one of these classes. Case (1) gives the leading contribution to neutrino mass naturally and a classic example of this class is the Zee model. We demonstrate that in order to prevent that a tree level contribution dominates in case (2), Majorana fermions running in the loop and an additional $\\mathbb{Z}_2$ symmetry are needed for a genuinely leading one-loop contribution. In the type-II loop extensions, the lepton number violating coupling will be generated at one loop, whereas the type-I/III extensions can be interpreted as loop-induced inverse or linear seesaw mechanisms. For the divergent diagrams in category (3), the tree level contribution cannot be ...
Effective Actions of IIB Matrix Model on S^3
Kaneko, Hiromichi; Matsumoto, Koichiro
2007-01-01
S^3 is a simple principle bundle which is locally S^2 \\times S^1. It has been shown that such a space can be constructed in terms of matrix models. It has been also shown that such a space can be realized by a generalized compactification procedure in the S^1 direction. We investigate the effective action of supersymmetric gauge theory on S^3 with an angular momentum cutoff and that of a matrix model compactification. The both cases can be realized in a deformed IIB matrix model with a Myers Term. We find that the highly divergent contributions at the tree and one loop level are sensitive to the uv cutoff. However the two loop level contributions are universal since they are only logarithmically divergent. We expect that the higher loop contributions are insensitive to the uv cutoff since 3d gauge theory is super renormalizable.
A Proposal for a Standard Interface Between Monte Carlo Tools And One-Loop Programs
Energy Technology Data Exchange (ETDEWEB)
Binoth, T.; /Edinburgh U.; Boudjema, F.; /Annecy, LAPP; Dissertori, G.; Lazopoulos, A.; /Zurich, ETH; Denner, A.; /PSI, Villigen; Dittmaier, S.; /Freiburg U.; Frederix, R.; Greiner, N.; Hoeche, Stefan; /Zurich U.; Giele, W.; Skands, P.; Winter, J.; /Fermilab; Gleisberg, T.; /SLAC; Archibald, J.; Heinrich, G.; Krauss, F.; Maitre, D.; /Durham U., IPPP; Huber, M.; /Munich, Max Planck Inst.; Huston, J.; /Michigan State U.; Kauer, N.; /Royal Holloway, U. of London; Maltoni, F.; /Louvain U., CP3 /Milan Bicocca U. /INFN, Turin /Turin U. /Granada U., Theor. Phys. Astrophys. /CERN /NIKHEF, Amsterdam /Heidelberg U. /Oxford U., Theor. Phys.
2011-11-11
Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenological predictions at the next-to-leading order level. This note summarises the discussion of the next-to-leading order multi-leg (NLM) working group on this issue which has been taking place during the workshop on Physics at TeV Colliders at Les Houches, France, in June 2009. The result is a proposal for a standard interface between Monte Carlo tools and one-loop matrix element programs.
A proposal for a standard interface between Monte Carlo tools and one-loop programs
Energy Technology Data Exchange (ETDEWEB)
Binoth, T.; Boudjema, F.; Dissertori, G.; Lazopoulos, A.; Denner, A.; Dittmaier, S.; Frederix, R.; Greiner, N.; Hoche, S.; Giele, W.; Skands, P.
2010-01-01
Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenological predictions at the next-to-leading order level. This note summarizes the discussion of the next-to-leading order multi-leg (NLM) working group on this issue which has been taking place during the workshop on Physics at TeV colliders at Les Houches, France, in June 2009. The result is a proposal for a standard interface between Monte Carlo tools and one-loop matrix element programs.
One-loop approximation of Mφller scattering in generalized Krein-space quantization
Institute of Scientific and Technical Information of China (English)
F. PAYANDEH; M. MEHRAFARIN; M. V. TAKOOK
2009-01-01
It has been shown that the negative-norm states necessarily appear in a covariant quantization of the free minimally coupled scalar field in de Sitter spacetime. In this processes ultraviolet and infrared di-vergences have been automatically eliminated. A natural renormalization of the one-loop interacting quantum field in Minkowski spacetime (λψ4) has been achieved through the consideration of the nega-tive-norm states defined in Krein space. It has been shown that the combination of quantum field theory in Krein space together with consideration of quantum metric fluctuation, results in quantum field the-cry without any divergences. Pursuing this approach, we express Wick's theorem and calculate Mφiler scattering in the one-loop approximation in generalized Krein space. The mathematical consequence of this method is the disappearance of the ultraviolet divergence in the one-loop approximation.
One-loop approximation of Mφller scattering in generalized Krein-space quantization
Institute of Scientific and Technical Information of China (English)
F.; PAYANDEH; M.; MEHRAFARIN; M.; V.; TAKOOK
2009-01-01
It has been shown that the negative-norm states necessarily appear in a covariant quantization of the free minimally coupled scalar field in de Sitter spacetime. In this processes ultraviolet and infrared di- vergences have been automatically eliminated. A natural renormalization of the one-loop interacting quantum field in Minkowski spacetime (λφ 4) has been achieved through the consideration of the nega- tive-norm states defined in Krein space. It has been shown that the combination of quantum field theory in Krein space together with consideration of quantum metric fluctuation, results in quantum field the- ory without any divergences. Pursuing this approach, we express Wick’s theorem and calculate Mφller scattering in the one-loop approximation in generalized Krein space. The mathematical consequence of this method is the disappearance of the ultraviolet divergence in the one-loop approximation.
Third generation sfermions decays into Z and W gauge bosons: full one-loop analysis
Arhrib, A; Arhrib, Abdesslam; Benbrik, Rachid
2004-01-01
The complete one-loop radiative corrections to third generation scalar fermions into gauge bosons Z and W^\\pm is considered. We focus on \\wt{f}_2 \\to Z \\wt{f}_1 and \\wt{f}_i \\to W^\\pm \\wt{f'}_1 (f,f'=t,b). We include both SUSY-QCD, QED and full electroweak corrections. It is found that the electroweak corrections can be of the same order as the SUSY-QCD corrections. The two sets of corrections interfere destructively in some region of parameter space. The full one loop correction can reach 10% in some SUGRA scenario, while in model independent analysis like general MSSM, the one loop correction can reach 20% for large \\tan\\beta and large trilinear soft breaking terms A_b.
Recursive generation of one-loop amplitudes in the Standard Model
Actis, Stefano; Hofer, Lars; Scharf, Andreas; Uccirati, Sandro
2012-01-01
We introduce the computer code Recola for the recursive generation of tree-level and one-loop amplitudes in the Standard Model. Tree-level amplitudes are constructed using off-shell currents instead of Feynman diagrams as basic building blocks. One-loop amplitudes are represented as linear combinations of tensor integrals whose coefficients are calculated similarly to the tree-level amplitudes by recursive construction of loop off-shell currents. We introduce a novel algorithm for the treatment of colour, assigning a colour structure to each off-shell current which enables us to recursively construct the colour structure of the amplitude efficiently. Recola is interfaced with a tensor-integral library and provides complete one-loop Standard Model amplitudes including rational terms and counterterms. As a first application we consider Z+2jets production at the LHC and calculate with Recola the next-to-leading-order electroweak corrections to the dominant partonic channels.
One-loop calculations in quantum field theory: from Feynman diagrams to unitarity cuts
Energy Technology Data Exchange (ETDEWEB)
Ellis, R. Keith [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Kunszt, Zoltan [Institute for Theoretical Physics (Switzerland); Melnikov, Kirill [Johns Hopkins Univ., Baltimore, MD (United States); Zanderighi, Giulia [Rudolf Peierls Centre for Theoretical Physics (United Kingdom)
2012-09-01
The success of the experimental program at the Tevatron re-inforced the idea that precision physics at hadron colliders is desirable and, indeed, possible. The Tevatron data strongly suggests that one-loop computations in QCD describe hard scattering well. Extrapolating this observation to the LHC, we conclude that knowledge of many short-distance processes at next-to-leading order may be required to describe the physics of hard scattering. While the field of one-loop computations is quite mature, parton multiplicities in hard LHC events are so high that traditional computational techniques become inefficient. Recently new approaches based on unitarity have been developed for calculating one-loop scattering amplitudes in quantum field theory. These methods are especially suitable for the description of multi-particle processes in QCD and are amenable to numerical implementations. We present a systematic pedagogical description of both conceptual and technical aspects of the new methods.
One-loop $\\mathbf{\\beta}$-function of noncommutative scalar $QED_{4}$
Ghasemkhani, M; Rahmanpour, V; Nouri, E
2016-01-01
In this paper we consider the $\\beta$-function at one-loop approximation for noncommutative scalar QED. The renormalization of the full theory, including the basic vertices, and the renormalization group equation are fully established. Next, the complete set of the one-loop diagrams corresponding to the first-order radiative corrections to the basic functions is considered: gauge, charged scalar and ghost fields self-energies, three- and four-point vertex functions $\\left$ and $\\left$, respectively. We pay special attention to the noncommutative contributions to the renormalization constants. To conclude, the one-loop $\\beta$-function of noncommutative scalar QED is then computed and comparison to known results is presented.
Electric dipole moments of charged leptons at one loop in presence of massive neutrinos
Novales-Sánchez, H; Toscano, J J; Vázquez-Hernández, O
2016-01-01
Violation of $CP$ invariance is a quite relevant phenomenon that is found in the Standard Model, though in small amount. This has been an incentive to look for high-energy descriptions in which $CP$ violation is increased, thus enhancing effects that are suppressed in the Standard Model, such as the electric dipole moments of elementary particles. In the present investigation, we point out that charged currents in which axial couplings are different from vector couplings are able to produce one-loop contributions to electric dipole moments of charged leptons if neutrinos are massive and if these currents violate $CP$. We develop our discussion around charged currents involving heavy neutrinos and a $W'$ gauge boson coupling to Standard Model charged leptons. Using the most stringent bound on the electron electric dipole moment, provided by the ACME Collaboration, we determine that the difference between axial and vector currents lies within $\\sim10^{-10}$ and $\\sim10^{-11}$ for heavy-neutrino masses between $...
Analytic one-loop amplitudes for a Higgs boson plus four partons
Energy Technology Data Exchange (ETDEWEB)
Dixon, Lance J.; Sofianatos, Yorgos; /SLAC
2009-06-02
We compute the one-loop QCD amplitudes for the processes H{anti q}q{anti Q}Q and H{anti q}qgg, the latter restricted to the case of opposite-helicity gluons. Analytic expressions are presented for the color- and helicity-decomposed amplitudes. The coupling of the Higgs boson to gluons is treated by an effective interaction in the limit of large top quark mass. The Higgs field is split into a complex field {phi} and its complex conjugate {phi}{sup {dagger}}. The split is useful because amplitudes involving {phi} have different analytic structure from those involving {phi}{sup {dagger}}. We compute the cut-containing pieces of the amplitudes using generalized unitarity. The remaining rational parts are obtained by on-shell recursion. Our results for H{anti q}q{anti Q}Q agree with previous semi-numerical computations. We also show how to convert existing semi-numerical results for the production of a scalar Higgs boson into analogous results for a pseudoscalar Higgs boson.
GoSam. A program for automated one-loop calculations
Energy Technology Data Exchange (ETDEWEB)
Cullen, G. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Greiner, N.; Heinrich, G.; Reiter, T. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Luisoni, G. [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Mastrolia, P. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Padua Univ. (Italy). Dipt. di Fisica; Ossola, G. [City Univ. of New York, NY (United States). New York City College of Technology; Tramontano, F. [European Organization for Nuclear Research (CERN), Geneva (Switzerland)
2011-11-15
The program package GoSam is presented which aims at the automated calculation of one-loop amplitudes for multi-particle processes. The amplitudes are generated in terms of Feynman diagrams and can be reduced using either D-dimensional integrand-level decomposition or tensor reduction, or a combination of both. GoSam can be used to calculate one-loop corrections to both QCD and electroweak theory, and model files for theories Beyond the Standard Model can be linked as well. A standard interface to programs calculating real radiation is also included. The flexibility of the program is demonstrated by various examples. (orig.)
Automation of One-Loop Calculations with GoSam: Present Status and Future Outlook
Cullen, Gavin; Heinrich, Gudrun; Luisoni, Gionata; Mastrolia, Pierpaolo; Ossola, Giovanni; Reiter, Thomas; Tramontano, Francesco
2011-01-01
In this presentation, we describe the GoSam (Golem/Samurai) framework for the automated computation of multi-particle scattering amplitudes at the one-loop level. The amplitudes are generated analytically in terms of Feynman diagrams, and can be evaluated using either D-dimensional integrand reduction or tensor decomposition. GoSam can be used to compute one-loop corrections to Standard Model (QCD and EW) processes, and it is ready to link generic model files for theories Beyond SM. We show the main features of GoSam through its application to several examples of different complexity.
On one-loop entanglement entropy of two short intervals from OPE of twist operators
Li, Zhibin
2016-01-01
We investigate the one-loop entanglement entropy of two short intervals with small cross ratio $x$ on a complex plane in two-dimensional conformal field theory (CFT) using operator product expansion of twist operators. We focus on the one-loop entanglement entropy instead of the general order $n$ R\\'enyi entropy, and this makes the calculation much easier. We consider the contributions of stress tensor to order $x^{10}$, contributions of $W_3$ operator to order $x^{12}$, and contributions of $W_4$ operator to order $x^{14}$. The CFT results agree with the ones in gravity.
Action-Specific Effects Underwater
Witt, Jessica; Schuck, Donald M; Taylor, J. Eric T.
2011-01-01
Action-specific effects on perception are apparent in terrestrial environments. For example, targets that require more effort to walk, jump, or throw to look farther away than when the targets require less effort. Here, we examined whether action-specific effects would generalize to an underwater environment. Instead, perception might be geometrically precise, rather than action-specific, in an environment that is novel from an evolutionary perspective. We manipulated ease to swim by giving p...
One-loop pentagon integral in $d$ dimensions from differential equations in $\\epsilon$-form
Kozlov, Mikhail G
2015-01-01
We apply differential equations technique to the calculation of the one-loop massless diagram with five onshell legs. Using reduction to $\\epsilon$-form, we manage to obtain a simple one-fold integral representation exact in space-time dimensionality. Expansion of the obtained result in $\\epsilon$ and analytical continuation to physical regions are discussed.
Appell functions and the scalar one-loop three-point integrals in Feynman diagrams
Energy Technology Data Exchange (ETDEWEB)
Cabral-Rosetti, L G [Departamento de Posgrado, Centro Interdisciplinario de Investigacion y Docencia en Educacion Tecnica (CIIDET), Av. Universidad 282 Pte., Col. Centro, A. Postal 752, C.P. 76000, Santiago de Queretaro, Qro. (Mexico); Sanchis-Lozano, M A [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, 46100 Burjassot, Valencia (Spain)
2006-05-15
The scalar three-point function appearing in one-loop Feynman diagrams is compactly expressed in terms of a generalized hypergeometric function of two variables. Use is made of the connection between such Appell function and dilogarithms coming from a previous investigation. Special cases are obtained for particular values of internal masses and external momenta.
Appell Functions and the Scalar One-Loop Three-point Integrals in Feynman Diagrams
Cabral-Rosetti, L G; Cabral-Rosetti, Luis G.; Sanchis-Lozano, Miguel A.
2006-01-01
The scalar three-point function appearing in one-loop Feynman diagrams is compactly expressed in terms of a generalized hypergeometric function of two variables. Use is made of the connection between such Appell function and dilogarithms coming from a previous investigation. Special cases are obtained for particular values of internal masses and external momenta.
One-loop helicity amplitudes for t anti t production at hadron colliders
Energy Technology Data Exchange (ETDEWEB)
Badger, Simon [The Niels Bohr International Academy and Discovery Center, Copenhagen (Denmark). Niels Bohr Inst.; Sattler, Ralf [Humboldt Univ. Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Yundin, Valery [Silesia Univ., Katowice (Poland). Inst. of Physics; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2011-01-15
We present compact analytic expressions for all one-loop helicity amplitudes contributing to t anti t production at hadron colliders. Using recently developed generalised unitarity methods and a traditional Feynman based approach we produce a fast and flexible implementation. (ORIG.)
Higgs-Higgs Interaction. The One-Loop Amplitude in the Standard Model
Dvoeglazov, Valeriy V
2016-01-01
The amplitude of Higgs-Higgs interaction is calculated in the Standard Model in the framework of the Sirlin's renormalization scheme in the unitary gauge. The one-loop corrections for lambda, the constant of 4-chi interaction are compared with the previous results of L. Durand et al. obtained on using the technique of the equivalence theorem, and in the different gauges.
Attacking One-loop Multi-leg Feynman Integrals with the Loop-Tree Duality
Chachamis, Grigorios; Draggiotis, Petros; Rodrigo, German
2016-01-01
We discuss briefly the first numerical implementation of the Loop-Tree Duality (LTD) method. We apply the LTD method in order to calculate ultraviolet and infrared finite multi-leg one-loop Feynman integrals. We attack scalar and tensor integrals with up to six legs (hexagons). The LTD method shows an excellent performance independently of the number of external legs.
One-loop Quantum Electrodynamic Correction to the Gravitational Potentials on de Sitter
Wang, C L
2015-01-01
We compute the one loop photon contribution to the graviton self-energy on de Sitter background and use it to solve the linearized Einstein equation for a point mass. Our results show that a co-moving observer sees a logarithmic spatial running Newton's constant. Equivalently a static observer reports a secular suppression of the Newtonian potential.
The complete one-loop spin chain for N=2 Super-Yang-Mills
Vecchia, P D
2004-01-01
We show that the complete planar one-loop mixing matrix of the N=2 Super Yang--Mills theory can be obtained from a reduction of that of the N=4 theory. For composite operators of scalar fields, this yields an anisotropic XXZ spin chain, whose spectrum of excitations displays a mass gap.
Symmetric point four-point functions at one loop in QCD
Gracey, J. A.
2017-03-01
We evaluate the quartic ghost and quark Green's functions as well as the gluon-ghost, gluon-quark and ghost-quark four-point functions of quantum chromodynamics at one loop at the fully symmetric point in a linear covariant gauge. Similar expressions for the analogous Green's functions in quantum electrodynamics are also provided.
Algebraic reduction of one-loop Feynman diagrams to scalar integrals. Pt 2. [LERG-I
Energy Technology Data Exchange (ETDEWEB)
Stuart, R.G. (Centro de Investigacion y Estudios Avanzados, Dept. di Fisica, Mexico City (Mexico)); Gongora-T, A. (Universidad Nacional Autonoma de Mexico, Inst. de Fisica, Mexico City (Mexico))
1990-01-01
An extended scheme for the reduction of one-loop form factors occurring in a general gauged quantum field theory to scalar integrals is discussed and an alternative method that may be applied in the case when the scheme fails is indicated. The extensions are implemented in a new version of the package LERG-I, written in REDUCE. (orig.).
Colour decompositions of multi-quark one-loop QCD amplitudes
DEFF Research Database (Denmark)
Ita, Harald; Ozeren, Kemal
2012-01-01
We describe the decomposition of one-loop QCD amplitudes in terms of colour-ordered building blocks. We give new expressions for the coefficients of QCD colour structures in terms of ordered objects called primitive amplitudes, for processes with up to seven partons. These results are needed...
Complete low-energy effective action in N=4 SYM: a direct N=2 supergraph calculation
Energy Technology Data Exchange (ETDEWEB)
Buchbinder, I.L. E-mail: joseph@tspu.edu.ru; Ivanov, E.A. E-mail: eivanov@thsun1.jinr.ru; Petrov, A.Yu. E-mail: petrov@fma.if.usp.brpetrov@tspu.edu.ru
2003-03-10
Using the covariant N=2 harmonic supergraph techniques we calculate the one-loop low-energy effective action of N=4 super-Yang-Mills theory in Coulomb branch with gauge group SU(2) spontaneously broken down to U(1). The full dependence of the low-energy effective action on both the hypermultiplet and gauge fields is determined. The direct quantum calculation confirms the correctness of the exact N=4 SYM low-energy effective action derived in on the purely algebraic ground by invoking a hidden N=2 supersymmetry which completes the manifest N=2 one to N=4. Our results provide an exhaustive solution to the problem of finding out the exact completely N=4 supersymmetric low-energy effective action for the theory under consideration.
Self-Duality Helicity and Higher-Loop Euler-Heisenberg Effective Actions
Dunne, Gerald V.; Schubert, Christian
2004-10-01
The Euler-Heisenberg effective action in a self-dual background is remarkably simple at two-loop. This simplicity is due to the inter-relationship between self-duality, helicity and supersymmetry. Applications include two-loop helicity amplitudes, beta-functions and nonperturbative effects. The two-loop Euler-Heisenberg effective Lagrangian for QED in a self-dual background field is naturally expressed in terms of one-loop quantities. This mirrors similar behavior recently found in two-loop amplitudes in N=4 SUSY Yang-Mills theory.
One loop quantum fluctuations to the energy of the non-topological soliton in Friedberg-Lee model
Shu, Song
2016-01-01
I have used a practical method to calculate the one-loop quantum correction to the energy of the non-topological soliton in Friedberg-Lee model. The quantum effects which come from the quarks of the Dirac sea scattering with the soliton bag are calculated by a summation of the discrete and continuum energy spectrum of the Dirac equation in the background field of soliton. The phase shift of the continuum spectrum is numerically calculated in an efficient way and all the divergences are removed by the same renormalization procedure.
arXiv Cuts from residues: the one-loop case
Abreu, Samuel; Duhr, Claude; Gardi, Einan
2017-06-14
Using the multivariate residue calculus of Leray, we give a precise definition of the notion of a cut Feynman integral in dimensional regularization, as a residue evaluated on the variety where some of the propagators are put on shell. These are naturally associated to Landau singularities of the first type. Focusing on the one-loop case, we give an explicit parametrization to compute such cut integrals, with which we study some of their properties and list explicit results for maximal and next-to-maximal cuts. By analyzing homology groups, we show that cut integrals associated to Landau singularities of the second type are specific combinations of the usual cut integrals, and we obtain linear relations among different cuts of the same integral. We also show that all one-loop Feynman integrals and their cuts belong to the same class of functions, which can be written as parametric integrals.
Quantum magnetic flux lines, BPS vortex zero modes, and one-loop string tension shifts
Alonso-Izquierdo, A.; Mateos Guilarte, J.; de la Torre Mayado, M.
2016-08-01
Spectral heat kernel/zeta function regularization procedures are employed in this paper to control the divergences arising from vacuum fluctuations of Bogomolnyi-Prasad-Sommerfield vortices in the Abelian Higgs model. Zero modes of vortex fluctuations are the source of difficulties appearing when the standard Gilkey-de Witt expansion is the tool used in the calculations of one-loop shifts of vortex masses and string tensions. A modified GdW expansion is developed to diminish the impact of the infrared divergences due to the vortex zero modes of fluctuation. With this new technique at our disposal we compute the one-loop vortex mass shifts in the planar AHM and the quantum corrections to the string tension of the magnetic flux tubes living in three dimensions. In both cases it is observed that weak repulsive forces surge between these classically noninteracting topological defects caused by vacuum quantum fluctuations.
On-shell recurrence relations for one-loop QCD amplitudes
Bern, Zvi; Kosower, David A
2005-01-01
We present examples of on-shell recurrence relations for determining rational functions appearing in one-loop QCD amplitudes. In particular, we give relations for one-loop QCD amplitudes with all legs of positive helicity, or with one leg of negative helicity and the rest of positive helicity. Our recursion relations are similar to the tree-level ones described by Britto, Cachazo, Feng and Witten. A number of new features arise for loop amplitudes in non-supersymmetric theories like QCD, including boundary terms and double poles. We show how to eliminate the boundary terms, which would interfere with obtaining useful relations. Using the relations we give compact explicit expressions for the n-gluon amplitudes with one negative-helicity gluon, up through n=7.
Package-X: A Mathematica package for the analytic calculation of one-loop integrals
Patel, Hiren H.
2015-12-01
Package-X, a Mathematica package for the analytic computation of one-loop integrals dimensionally regulated near 4 spacetime dimensions is described. Package-X computes arbitrarily high rank tensor integrals with up to three propagators, and gives compact expressions of UV divergent, IR divergent, and finite parts for any kinematic configuration involving real-valued external invariants and internal masses. Output expressions can be readily evaluated numerically and manipulated symbolically with built-in Mathematica functions. Emphasis is on evaluation speed, on readability of results, and especially on user-friendliness. Also included is a routine to compute traces of products of Dirac matrices, and a collection of projectors to facilitate the computation of fermion form factors at one-loop. The package is intended to be used both as a research tool and as an educational tool.
Non-gaussianity at tree- and one-loop levels from vector field perturbations
Valenzuela-Toledo, Cesar A; Lyth, David H
2009-01-01
We study the spectrum P_\\zeta and bispectrum B_\\zeta of the primordial curvature perturbation \\zeta when the latter is generated by scalar and vector field perturbations. The tree-level and one-loop contributions from vector field perturbations are worked out considering the possibility that the one-loop contributions may be dominant over the tree level terms (both (either) in P_\\zeta and (or) in B_\\zeta) and viceversa. The level of non-gaussianity in the bispectrum, f_{NL}, is calculated and related to the level of statistical anisotropy in the power spectrum, g_\\zeta. For very small amounts of statistical anisotropy in the power spectrum, the level of non-gaussianity may be very high, in some cases exceeding the current observational limit.
All One-loop Maximally Helicity Violating Gluonic Amplitudes in QCD
Energy Technology Data Exchange (ETDEWEB)
Berger, Carola F.; Bern, Zvi; Dixon, Lance J.; Forde, Darren; Kosower, David A.
2006-07-05
We use on-shell recursion relations to compute analytically the one-loop corrections to maximally-helicity-violating n-gluon amplitudes in QCD. The cut-containing parts have been computed previously; our work supplies the remaining rational parts for these amplitudes, which contain two gluons of negative helicity and the rest positive, in an arbitrary color ordering. We also present formulae specific to the six-gluon cases, with helicities (-+-+++) and (-++-++), as well as numerical results for six, seven, and eight gluons. Our construction of the n-gluon amplitudes illustrates the relatively modest growth in complexity of the on-shell-recursive calculation as the number of external legs increases. These amplitudes add to the growing body of one-loop amplitudes known for all n, which are useful for studies of general properties of amplitudes, including their twistor-space structure.
One-Loop Corrections of Single Spin Asymmetries at Twist-3 in Drell-Yan Processes
Chen, A P; Zhang, G P
2016-01-01
We study single spin asymmetries at one-loop accuracy in Drell-Yan processes in which one of the initial hadrons is transversely polarized. The spin-dependent part of differential cross-sections can be factorized with various hadronic matrix elements of twist-2 and twist-3 operators. These operators can be of even- and odd-chirality. In this work, the studied observables of asymmetries are differential cross-sections with different weights. These weights are selected so that the observables are spin-dependent and their virtual corrections are completely determined by quark form factor. In the calculations of one-loop corrections we meet collinear divergences in the contributions involving chirality-odd and chirality-even operators. We find that all of the divergences can be correctly subtracted. Therefore, our results give an explicit example of QCD factorization with twist-3 operators, especially, QCD factorization with chirality-odd twist-3 operators.
One-Loop Corrected Thermodynamics of the Extremal and Non-Extremal Spinning BTZ Black Hole
Medved, A J M
2001-01-01
We consider the one-loop corrected geometry and thermodynamics of a rotating BTZ black hole by way of a dimensionally reduced dilaton model. The analysis begins with a comprehensive study of the non-extremal solution after which two different methods are invoked to study the extremal case. The first approach considers the extremal limit of the non-extremal calculations, whereas the second treatment is based on the following conjecture: extremal and non-extremal black holes ae qualitatively distinct entities. We show that only the latter method yields regularity and consistency at the one-loop level. This is suggestive of a generalized third law of thermodynamics that forbids continuous evolution from non-extremal to extremal black hole geometries.
Scale-Invariant Models with One-Loop Neutrino Mass and Dark Matter Candidates
Ahriche, Amine; McDonald, Kristian L; Nasri, Salah
2016-01-01
We construct a list of minimal scale-invariant models at the TeV scale that generate one-loop neutrino mass and give viable dark matter candidates. The models generically contain a singlet scalar and a $Z_2$-odd sector comprised of singlet, doublet and/or triplet SU(2) multiplets. The dark matter may reside in a single multiplet or arise as an admixture of several multiplets. We find fifteen independent models, for which the dark matter is a viable candidate and neutrino mass results from a diagram with just one of the irreducible scale-invariant one-loop topologies. A further eight "non-pure" cases give hybrid one-/two-loop masses. All models predict new TeV scale physics, including a singlet scalar that generically mixes with the Higgs boson.
Consistency in Regularizations of the Gauged NJL Model at One Loop Level
Battistel, O A
1999-01-01
In this work we revisit questions recently raised in the literature associated to relevant but divergent amplitudes in the gauged NJL model. The questions raised involve ambiguities and symmetry violations which concern the model's predictive power at one loop level. Our study shows by means of an alternative prescription to handle divergent amplitudes, that it is possible to obtain unambiguous and symmetry preserving amplitudes. The procedure adopted makes use solely of {\\it general} properties of an eventual regulator, thus avoiding an explicit form. We find, after a thorough analysis of the problem that there are well established conditions to be fulfiled by any consistent regularization prescription in order to avoid the problems of concern at one loop level.
The Structure of n-Point One-Loop Open Superstring Amplitudes
Mafra, Carlos R
2014-01-01
In this article we present the worldsheet integrand for one-loop amplitudes in maximally supersymmetric superstring theory involving any number n of massless open string states. The polarization dependence is organized into the same BRST invariant kinematic combinations which also govern the leading string correction to tree level amplitudes. The dimensions of the bases for both the kinematics and the associated worldsheet integrals is found to be the unsigned Stirling number S_3^{n-1} of first kind. We explain why the same combinatorial structures govern on the one hand finite one-loop amplitudes of equal helicity states in pure Yang Mills theory and on the other hand the color tensors at quadratic alpha prime order of the color dressed tree amplitude.
Systematics of one-loop Yang-Mills diagrams from bosonic string amplitudes
Frizzo, A; Russo, R; Frizzo, Alberto; Magnea, Lorenzo; Russo, Rodolfo
2001-01-01
We present a general algorithm to compute off-shell, one-loop multigluon Green functions using bosonic string amplitudes. We identify and parametrize the regions in the space of moduli of one-loop Riemann surfaces that contribute to the field theory limit of string amplitudes. Each of these regions can be precisely associated with a Feynman-like scalar graph with cubic and quartic vertices, whose lines represent the joint propagation of ghosts and gluons. We give a procedure to compute the contribution of each graph to a gluon Green function, for arbitrarily polarized off-shell gluons, reducible and irreducible diagrams, planar and non-planar topologies. Explicit examples are given for up to six gluons.
String-inspired BCJ numerators for one-loop MHV amplitudes
Energy Technology Data Exchange (ETDEWEB)
He, Song [State Key Laboratory of Theoretical Physics and Kavli Institute for Theoretical Physics China,Institute of Theoretical Physics, Chinese Academy of Sciences,Beijing 100190 (China); Perimeter Institute for Theoretical Physics,Waterloo, ON N2L 2Y5 (Canada); School of Natural Sciences, Institute for Advanced Study,Princeton, NJ 08540 (United States); Monteiro, Ricardo [Mathematical Institute, University of Oxford,Oxford OX2 6GG (United Kingdom); Schlotterer, Oliver [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,14476 Potsdam (Germany)
2016-01-27
We find simple expressions for the kinematic numerators of one-loop MHV amplitudes in maximally supersymmetric Yang-Mills theory and supergravity, at any multiplicity. The gauge-theory numerators satisfy the Bern-Carrasco-Johansson (BCJ) duality between color and kinematics, so that the gravity numerators are simply the square of the gauge-theory ones. The duality holds because the numerators can be written in terms of structure constants of a kinematic algebra, which is familiar from the BCJ organization of self-dual gauge theory and gravity. The close connection that we find between one-loop amplitudes in the self-dual case and in the maximally supersymmetric case is reminiscent of the dimension-shifting formula. The starting point for arriving at our expressions is the dimensional reduction of ten-dimensional amplitudes obtained in the field-theory limit of open superstrings.
Package-X: A Mathematica package for the analytic calculation of one-loop integrals
Patel, Hiren H
2015-01-01
Package-X, a Mathematica package for the analytic computation of one-loop integrals dimensionally regulated near 4 spacetime dimensions is described. Package-X computes arbitrarily high rank tensor integrals with up to three propagators, and gives compact expressions of UV divergent, IR divergent, and finite parts for any kinematic configuration involving real-valued external invariants and internal masses. Output expressions can be readily evaluated numerically and manipulated symbolically with built-in Mathematica functions. Emphasis is on evaluation speed, on readability of results, and especially on user-friendliness. Also included is a routine to compute traces of products of Dirac matrices, and a collection of projectors to facilitate the computation of fermion form factors at one-loop. The package is intended to be used both as a research tool and as an educational tool.
String-motivated one-loop amplitudes in gauge theories with half-maximal supersymmetry
Berg, Marcus; Buchberger, Igor; Schlotterer, Oliver
2017-07-01
We compute one-loop amplitudes in six-dimensional Yang-Mills theory with half-maximal supersymmetry from first principles: imposing gauge invariance and locality on an ansatz made from string-theory inspired kinematic building blocks yields unique expressions for the 3- and 4-point amplitudes. We check that the results are reproduced in the field-theory limit α ' → 0 of string amplitudes in K3 orbifolds, using simplifications made in a companion string-theory paper [1].
$\\gamma\\gamma$ \\to $\\pi\\pi\\pi$ to one loop in chiral perturbation theory
Talavera, P; Bijnens, J; Bramon, A; Cornet, F
1995-01-01
The \\gamma\\gamma \\to \\pi^0 \\pi^0 \\pi^0 and \\gamma\\gamma \\to \\pi^+ \\pi^- \\pi^0 amplitudes are discussed in the general context of Chiral Perturbation Theory (ChPT) to O(p^6). Chiral loops are found to play a major role. This makes these processes a good test of ChPT, mainly in its anomalous sector. We correct earlier numerical results at tree level and determine the one-loop results as well.
On the tensor reduction of one-loop pentagons and hexagons
Energy Technology Data Exchange (ETDEWEB)
Diakonidis, T.; Riemann, T.; Tausk, J.B. [Deutsches Elektronen-Synchrotron DESY, Zeuthen (Germany); Fleischer, J. [Deutsches Elektronen-Synchrotron DESY, Zeuthen (Germany)]|[Bielefeld Univ. (Germany). Fakultaet fuer Physik; Gluza, J.; Kajda, K. [Uniwersytet Slaski, Katowice (Poland). Inst. of Physics and Chemistry of Metals
2008-07-15
We perform analytical reductions of one-loop tensor integrals with 5 and 6 legs to scalar master integrals. They are based on the use of recurrence relations connecting integrals in different space-time dimensions. The reductions are expressed in a compact form in terms of signed minors, and have been implemented in a mathematica package called hexagon.m. We present several numerical examples. (orig.)
Unitarity cuts and Reduction to master integrals in d dimensions for one-loop amplitudes
Anastasiou, C; Feng, B; Kunszt, Z; Mastrolia, Pierpaolo; Anastasiou, Charalampos; Britto, Ruth; Feng, Bo; Kunszt, Zoltan; Mastrolia, Pierpaolo
2007-01-01
We present an alternative reduction to master integrals for one-loop amplitudes using a unitarity cut method in arbitrary dimensions. We carry out the reduction in two steps. The first step is a pure four-dimensional cut-integration of tree amplitudes with a mass parameter, and the second step is applying dimensional shift identities to master integrals. This reduction is performed at the integrand level, so that coefficients can be read out algebraically.
Complete one-loop calculations in the chargino/neutralino sector of the MSSM
Fritzsche, T
2004-01-01
The present status of the calculation of radiative corrections to chargino and neutralino pair production processes in the MSSM is summarized. The main focus will be on the use of the on-shell renormalization scheme for charginos and neutralinos in conjunction with DR-bar parameters, such as those of the SPA conventions. Associated soft and hard bremsstrahlung and an appropriate separation of QED-like parts in the full one-loop contributions will be addressed.
General $\\varepsilon$-representation for scalar one-loop Feynman integrals
Bluemlein, Johannes; Riemann, Tord
2015-01-01
A systematic study of the scalar one-loop two-, three-, and four-point Feynman integrals is performed. We consider all cases of mass assignment and external invariants and derive closed expressions in arbitrary space-time dimension in terms of higher transcendental functions. The integrals play a role as building blocks in general higher-loop or multi-leg processes. We also perform numerical checks of the calculations using AMBRE/MB and LoopTools/FF.
One-loop renormalization of fermionic currents with the overlap-Dirac operator
Alexandrou, C; Panagopoulos, H; Vicari, E
2000-01-01
We compute the one-loop lattice renormalization of the two-quark operators$\\bar{\\psi} \\Gamma \\psi$, where $\\Gamma$ denotes the generic Dirac matrix, forthe lattice formulation of QCD using the overlap-Dirac operator. We also study the renormalization of quark bilinears which are more extendedand have better chiral properties. Finally, we present improved estimates of these renormalization constants,coming from cactus resummation and from mean field perturbation theory.
One-loop corrections to the Higgs self-couplings in the singlet extension
Kanemura, Shinya; Kikuchi, Mariko; Yagyu, Kei
2017-04-01
We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state (H) appears in addition to the Higgs boson (h) with the mass 125 GeV. The hhh vertex is calculated at the one-loop level, and its possible deviation from the predictions in the standard model is evaluated under various theoretical constraints. The decay rate of H → hh is also computed at the one-loop level. We also take into account the bound from the precise measurement of the W boson mass, which gives the upper limit on the mixing angle α between two physical Higgs bosons for a given value of the mass of H (mH). We find that the deviation in the hhh coupling from the prediction in the standard model can maximally be about 250%, 150% and 75% for mH = 300, 500 and 1000 GeV, respectively, under the requirement that the cutoff scale of the model is higher than 3 TeV. We also discuss deviations from the standard model prediction in double Higgs boson production from the gluon fusion at the LHC using the one-loop corrected Higgs boson vertices.
Two-body decays of gluino at full one-loop level in the quark-flavour violating MSSM.
Eberl, Helmut; Ginina, Elena; Hidaka, Keisho
2017-01-01
We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalisation is done in the [Formula: see text] scheme. The gluon and photon radiations are included by adding the corresponding three-body decay widths. We discuss the dependence of the gluino decay widths on the QFV parameters. The main dependence stems from the [Formula: see text]-[Formula: see text] mixing in the decays to up-type squarks, and from the [Formula: see text]-[Formula: see text] mixing in the decays to down-type squarks due to the strong constraints from B-physics on the other quark-flavour-mixing parameters. The full one-loop corrections to the gluino decay widths are mostly negative and of the order of about -10%. The QFV part stays small in the total width but can vary up to -8% for the decay width into the lightest [Formula: see text] squark. For the corresponding branching ratio the effect is somehow washed out by at least a factor of two. The electroweak corrections can be as large as 35% of the SUSY QCD corrections.
Two-body decays of gluino at full one-loop level in the quark-flavour violating MSSM
Energy Technology Data Exchange (ETDEWEB)
Eberl, Helmut; Ginina, Elena [Institut fuer Hochenergiephysik der Oesterreichischen Akademie der Wissenschaften, Vienna (Austria); Hidaka, Keisho [Tokyo Gakugei University, Department of Physics, Tokyo (Japan)
2017-03-15
We study the two-body decays of the gluino at full one-loop level in the Minimal Supersymmetric Standard Model with quark-flavour violation (QFV) in the squark sector. The renormalisation is done in the DR scheme. The gluon and photon radiations are included by adding the corresponding three-body decay widths. We discuss the dependence of the gluino decay widths on the QFV parameters. The main dependence stems from the c{sub R}-t{sub R} mixing in the decays to up-type squarks, and from the s{sub R}-b{sub R} mixing in the decays to down-type squarks due to the strong constraints from B-physics on the other quark-flavour-mixing parameters. The full one-loop corrections to the gluino decay widths are mostly negative and of the order of about -10%. The QFV part stays small in the total width but can vary up to -8% for the decay width into the lightest u squark. For the corresponding branching ratio the effect is somehow washed out by at least a factor of two. The electroweak corrections can be as large as 35% of the SUSY QCD corrections. (orig.)
A Twistor Approach to One-Loop Amplitudes in N=1 Supersymmetric Yang-Mills Theory
Bedford, J; Spence, B; Travaglini, G; Bedford, James; Brandhuber, Andreas; Spence, Bill; Travaglini, Gabriele
2004-01-01
We extend the twistor string theory inspired formalism introduced in hep-th/0407214 for calculating loop amplitudes in N=4 super Yang-Mills theory to the case of N=1 (and N=2) super Yang-Mills. Our approach yields a novel representation of the gauge theory amplitudes as dispersion integrals, which are surprisingly simple to evaluate. As an application we calculate one-loop maximally helicity violating (MHV) scattering amplitudes with an arbitrary number of external legs. The result we obtain agrees precisely with the expressions for the N=1 MHV amplitudes derived previously by Bern, Dixon, Dunbar and Kosower using the cut-constructibility approach.
A solution for tensor reduction of one-loop N-point functions with N{>=}6
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2011-11-15
Collisions at the LHC produce many-particle final states, and for precise predictions the one-loop N-point corrections are needed. We study here the tensor reduction for Feynman integrals with N{>=}6. A general, recursive solution by Binoth et al. expresses N-point Feynman integrals of rank R in terms of (N-1)-point Feynman integrals of rank (R-1) (for N{>=}6). We show that the coefficients can be obtained analytically from suitable representations of the metric tensor. Contractions of the tensor integrals with external momenta can be efficiently expressed as well. We consider our approach particularly well suited for automatization. (orig.)
String-motivated one-loop amplitudes in gauge theories with half-maximal supersymmetry
Berg, Marcus; Schlotterer, Oliver
2016-01-01
We compute one-loop amplitudes in six-dimensional Yang-Mills theory with half-maximal supersymmetry from first principles: imposing gauge invariance and locality on an ansatz made from string-theory inspired kinematic building blocks yields unique expressions for the 3- and 4-point amplitudes. We check that the results are reproduced in the field-theory limit $\\alpha' \\rightarrow 0$ of string amplitudes in K3 orbifolds, using simplifications made in a companion string-theory paper 1603.05262.
COLLIER: A fortran-based complex one-loop library in extended regularizations
Denner, Ansgar; Dittmaier, Stefan; Hofer, Lars
2017-03-01
We present the library COLLIER for the numerical evaluation of one-loop scalar and tensor integrals in perturbative relativistic quantum field theories. The code provides numerical results for arbitrary tensor and scalar integrals for scattering processes in general quantum field theories. For tensor integrals either the coefficients in a covariant decomposition or the tensor components themselves are provided. COLLIER supports complex masses, which are needed in calculations involving unstable particles. Ultraviolet and infrared singularities are treated in dimensional regularization. For soft and collinear singularities mass regularization is available as an alternative.
The one loop contributions to c(t) electric dipole moment in the CP violating BLMSSM
Zhao, Shu-Min; Yang, Zhong-Jun; Zhang, Hai-Bin; Dong, Xing-Xing; Tao-Guo,
2016-01-01
In the CP violating supersymmetric extension of the standard model with local gauged baryon and lepton symmetries(BLMSSM), there are new CP violating sources which can give new contributions to the quark electric dipole moment (EDM). Considering the CP violating phases, we analyze the EDMs of the quarks c and t. We take into account the contributions from the one loop diagrams. The numerical results are analyzed with some assumptions on the relevant parameter space. The numerical results for the c and t EDMs can reach large values.
One loop photon-graviton mixing in an electromagnetic field: Part 1
Bastianelli, F; Bastianelli, Fiorenzo; Schubert, Christian
2005-01-01
Photon-graviton mixing in an electromagnetic field is a process of potential interest for cosmology and astrophysics. At the tree level it has been studied by many authors. We consider the one-loop contribution to this amplitude involving a charged spin 0 or spin 1/2 particle in the loop and an arbitrary constant field. In the first part of this article, the worldline formalism is used to obtain a compact two-parameter integral representation for this amplitude, valid for arbitrary photon energies and background field strengths. The calculation is manifestly covariant througout.
Refined counting of necklaces in one-loop N=4 SYM
Suzuki, Ryo
2017-06-01
We compute the grand partition function of N=4 SYM at one-loop in the SU(2) sector with general chemical potentials, extending the results of Pólya's theorem. We make use of finite group theory, applicable to all orders of perturbative 1 /N c expansion. We show that only the planar terms contribute to the grand partition function, which is therefore equal to the grand partition function of an ensemble of {XXX}_{1/2} spin chains. We discuss how Hagedorn temperature changes on the complex plane of chemical potentials.
One-loop contribution to the matter-driven expansion of the Universe
Broda, Bogusław
2015-01-01
Standard perturbative quantum gravity formalism is applied to compute the lowest order corrections to the spatially flat cosmological FLRW solution governed by ordinary matter. The presented approach is analogous to the one used to compute quantum corrections to the Coulomb potential in electrodynamics, or to the approach applied in computation of quantum corrections to the Schwarzschild solution in gravity. In this framework, it is shown that the corrections to the classical metric coming from the one-loop graviton vacuum polarization (self-energy) have (UV cutoff dependent) repulsive properties, which could be not negligible in the very early Universe.
On one-loop corrections in the CPT-even extension of QED
Belich, H; Nascimento, J R; Petrov, A Yu
2016-01-01
In this paper, we describe the generation of the CPT-even, aether-like terms via the new CPT-even magnetic-like coupling. We have carried out a study the loop corrections generated by this coupling. Previous investigations has been initiated on this issue and we have extended, first promoting the study to five dimensions where the theory is one-loop finite, second, in studying of higher-point functions, third, in studying of quantum corrections to vertices of the interaction.
One loop radiative corrections to the translation-invariant noncommutative Yukawa Theory
Bouchachia, Karim; Hachemane, Mahmoud; Schweda, Manfred
2015-01-01
We elaborate in this paper a translation-invariant model for fermions in 4-dimensional noncommutative Euclidean space. The construction is done on the basis of the renormalizable noncommutative translation-invariant Phi4 theory introduced by R. Gurau et al. We combine our model with the scalar model, in order to study the noncommutative pseudo-scalar Yukawa theory. After we derive the Feynman rules of the theory, we perform an explicit calculation of the quantum corrections at one loop level to the propagators and vertices.
Determining MSSM parameters via chargino production at the LC: a one-loop analysis
Bharucha, Aoife
2012-01-01
Very precise measurements of masses and cross sections are expected to be achievable with a future linear collider. With such an accuracy one must incorporate loop corrections in order to make meaningful predictions for the underlying new physics parameters. For the electroweakino sector, this involves fitting one-loop predictions to expected measurements of the cross section and forward-backward asymmetry for chargino pair production and of the accessible chargino and neutralino masses. We consider two scenarios with characteristic features, chosen taking recent LHC SUSY and Higgs searches into account. Our analysis allows the accurate determination of the desired parameters and, additionally, access to stop sector parameters that enter via loop corrections.
On one-loop corrections to matching conditions of lattice HQET including 1/m{sub b} terms
Energy Technology Data Exchange (ETDEWEB)
Korcyl, Piotr [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2013-12-15
HQET is an effective theory for QCD with N{sub f} light quarks and a massive valence quark if the mass of the latter is much bigger than LQCD. As any effective theory, HQET is predictive only when a set of parameters has been determined through a process called matching. The non-perturbative matching procedure including 1/m{sub b} terms, developed by the ALPHA collaboration, consists of 19 carefully chosen observables which are precisely computable in lattice QCD as well as in lattice HQET. The matching conditions are then a set of 19 equations which relate the QCD and HQET values of these observables. We present a study of one-loop corrections to two generic matching observables involving correlation function with an insertion of the A{sub 0} operator. Our results enable us to quantify the quality of the relevant observables in view of the envisaged nonperturbative implementation of this matching procedure.
One-loop corrections to the Higgs self-couplings in the singlet extension
Kanemura, Shinya; Yagyu, Kei
2016-01-01
We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state ($H$) appears in addition to the Higgs boson ($h$) with the mass 125 GeV. The $hhh$ vertex is calculated at the one-loop level, and its possible deviation from the predictions in the standard model is evaluated under various theoretical constraints. The decay rate of $H \\to hh$ is also computed at the one-loop level. We also take into account the bound from the precise measurement of the $W$ boson mass, which gives the upper limit on the mixing angle $\\alpha$ between two physical Higgs bosons for a given value of the mass of $H$ ($m_H^{}$). We find that the deviation in the $hhh$ coupling from the prediction in the standard model can maximally be about 250\\%, 150\\% and 75\\% for $m_H^{}=300$, 500 and 1000 GeV, respectively, under the requirement that the cutoff scale of the model is higher than 3 TeV. We also discuss...
PJFry. A C++ package for tensor reduction of one-loop Feynman integrals
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Yundin, V. [Copenhagen Univ. (Denmark). Niels Bohr International Academy and Discovery Center
2011-12-15
The C++ package PJFry 1.0.0 - a one loop tensor integral library - is introduced. We use an algebraic approach to tensor reduction. As a result, the tensor integrals are presented in terms of scalar one- to four-point functions, which have to be provided by an external library, e.g. QCDLoop/FF or OneLOop or LoopTools/FF. The reduction is implemented until five-point functions of rank five. A numerical example is shown, including a special treatment for small or vanishing inverse four-point Gram determinants. Future modules of PJFry might cover the treatment of n-point functions with n{>=}6; the corresponding formulae are worked out. Further, an extremely efficient approach to tensor reduction relies on evaluations of complete contractions of the tensor integrals with external momenta. For this, we worked out an algorithm for the analytical evaluation of sums over products of signed minors with scalar products of chords, i.e. differences of external momenta. As a result, the usual multiple sums over tensor coefficients are replaced for the numerical evaluation by compact combinations of the basic scalar functions. (orig.)
The corrections from one loop and two-loop Barr-Zee type diagrams to muon MDM in BLMSSM
Zhao, Shu-Min; Zhang, Hai-Bin; Yan, Ben; Zhan, Xi-Jie
2014-01-01
In a supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries(BLMSSM) and the Yukawa couplings between Higgs doublets and exotic quarks are considered, we study the one loop diagrams and the two-loop Barr-Zee type diagrams with a closed Fermi(scalar) loop between the vector Boson and Higgs. Using the effective Lagrangian method, we deduce the Wilson coefficients of dimension 6 operators contributing to the anomalous magnetic moment of muon, which satisfies the electromagnetic gauge invariance. In the numerical analysis, we consider the experiment constraints from Higgs and neutrino data. In some parameter space, the new physics contribution is large and even reaches $24\\times10^{-10}$, which can remedy the deviation well.
Mora, P J; Woodard, R P
2013-01-01
We use the Hartree approximation to the Einstein equation on de Sitter background to solve for the one loop correction to the graviton mode function. This should give a reasonable approximation to how the ensemble of inflationary gravitons affects a single external graviton. At late times we find that the one loop correction to the plane wave mode function $u(\\eta,k)$ goes like $G H^2 \\ln(a)/a^2$, where $a$ is the inflationary scale factor. One consequence is that the one loop corrections to the "electric" components of the linearized Weyl tensor grow compared to the tree order result.
One-loop superstring six-point amplitudes and anomalies in pure spinor superspace
Mafra, Carlos R.; Schlotterer, Oliver
2016-04-01
We present the massless six-point one-loop amplitudes in the open and closed superstring using BRST cohomology arguments from the pure spinor formalism. The hexagon gauge anomaly is traced back to a class of kinematic factors in pure spinor superspace which were recently introduced as BRST pseudo-invariants. This complements previous work where BRST invariance arguments were used to derive the non-anomalous part of the amplitude. The associated worldsheet functions are non-singular and demonstrated to yield total derivatives on moduli space upon gauge variation. These cohomology considerations yield an efficient organizing principle for closed-string amplitudes that match expectations from S-duality in the low-energy limit.
On quantum magnetic flux lines, BPS vortex zero modes, and one-loop string tension shifts
Alonso-Izquierdo, A; Mayado, M de la Torre
2016-01-01
Spectral heat kernel/zeta function regularization procedures are employed in this paper to control the divergences arising from vacuum fluctuations of Bogomolnyi-Prasad-Sommerfield vortices in the Abelian Higgs model. Zero modes of vortex fluctuations are the source of difficulties appearing when the standard Gilkey-de Witt expansion is performed. A modified GdW expansion is developed to diminish the impact of the infrared divergences due to the vortex zero modes. With this new technique at our disposal we compute the one-loop vortex mass shift in the planar AHM and the quantum corrections to the string tension of the magnetic flux tubes living in three dimensions. In both cases it is observed that weak repulsive forces surge between these classically non interacting topological defects caused by vacuum quantum fluctuations.
One-Loop Self-Dual and N=4 Super Yang-Mills
Bern, Z; Dunbar, D C; Kosower, D A
1997-01-01
We conjecture a simple relationship between the one-loop maximally helicity violating gluon amplitudes of ordinary QCD (all helicities identical) and those of N=4 supersymmetric Yang-Mills (all but two helicities identical). Because the amplitudes in self-dual Yang Mills have been shown to be the same as the maximally helicity violating ones in QCD, this conjecture implies that they are also related to the maximally helicity violating ones of N=4 supersymmetric Yang-Mills. We have an explicit proof of the relation up to the six-point amplitude; for amplitudes with more external legs, it remains a conjecture. A similar conjecture relates amplitudes in self-dual gravity to maximally helicity violating N=8 supergravity amplitudes.
NGluon. A package to calculate one-loop multi-gluon amplitudes
Energy Technology Data Exchange (ETDEWEB)
Badger, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Niels Bohr Institute, Copenhagen (Denmark). Niels Bohr International Academy and Discovery Center; Biedermann, B.; Uwer, P. [Humboldt Univ., Berlin (Germany). Inst. fuer Physik
2010-11-15
We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double precision the library yields reliable results for up to 14 gluons with only a small fraction of events requiring a re-evaluation using extended floating point arithmetic. We believe that the library presented here provides an important contribution to future LHC phenomenology. The program may also prove useful in cross checking results obtained by other methods. In addition, the code provides a sample implementation which may serve as a starting point for further developments. (orig.)
One-loop corrections to the Fermion masses and flavour symmetries
Energy Technology Data Exchange (ETDEWEB)
Grimus, Walter; Loeschner, Maximilian [Particle Physics Group, University of Vienna (Austria); Ludl, Patrick [SHEP, University of South Hampton (United Kingdom)
2016-07-01
Extensions of the Standard Model which explain non-vanishing neutrino masses and some of the peculiar features of the lepton mixing matrix by flavour symmetries always lead to a proliferation of scalars in the model. Then, the relation between Yukawa couplings and fermions in general involves several vacuum expectation values. It is therefore expedient to devise a renormalization procedure which is adapted to this situation. In this talk, we will present first results of an ongoing PhD project on one-loop corrections to fermion masses in a toy model featuring an arbitrary number of Majorana or Dirac fermions and scalar fields, testing the stability of tree level predictions and keeping focus on the renormalization of the vacuum expectation values. This can serve as a preliminary study of the radiative generation of the neutrino masses in explicit physical models, like the so called Scotogenic Model which will also be discussed in this talk.
The $\\mathcal{Q}$-cut Representation of One-loop Integrands and Unitarity Cut Method
Huang, Rijun; Rao, Junjie; Zhou, Kang; Feng, Bo
2015-01-01
Recently, a new construction for complete loop integrands of massless field theories has been proposed, with on-shell tree-level amplitudes delicately incorporated into its algorithm. This new approach reinterprets integrands in a novel form, namely the $\\mathcal{Q}$-cut representation. In this paper, by deriving one-loop integrands as examples, we elaborate in details the technique of this new representation, e.g., the summation over all possible $\\mathcal{Q}$-cuts as well as helicity states for the non-scalar internal particle in the loop. Moreover, we show that the integrand in the $\\mathcal{Q}$-cut representation naturally reduces to the integrand in the traditional unitarity cut method for each given cut channel, providing a cross-check for the new approach.
Analysis of the NMSSM Higgs Boson Masses at One-Loop Level
Ender, K; Muhlleitner, M; Rzehak, H
2012-01-01
For a reliable prediction of the NMSSM Higgs boson signatures at present and future high-energy colliders and a proper distinction of the NMSSM and MSSM Higgs sector the precise knowledge of the Higgs boson masses including higher-order corrections is indispensable. In this paper, the one-loop corrections to the neutral NMSSM Higgs boson masses and mixings are calculated in three different renormalisation schemes. In addition to the $\\bar{DR}$ renormalisation scheme, existing in the literature, two other schemes are adopted. Furthermore, the dependence on the value of the top quark mass is investigated. The resulting Higgs mass corrections have been compared and the residual theory error due to missing higher-order corrections can be estimated to be of the order of 10%.
One-loop superstring six-point amplitudes and anomalies in pure spinor superspace
Mafra, Carlos R
2016-01-01
We present the massless six-point one-loop amplitudes in the open and closed superstring using BRST cohomology arguments from the pure spinor formalism. The hexagon gauge anomaly is traced back to a class of kinematic factors in pure spinor superspace which were recently introduced as BRST pseudo-invariants. This complements previous work where BRST invariance arguments were used to derive the non-anomalous part of the amplitude. The associated worldsheet functions are non-singular and demonstrated to yield total derivatives on moduli space upon gauge variation. These cohomology considerations yield an efficient organizing principle for closed-string amplitudes that match expectations from S-duality in the low-energy limit.
The Complete One-Loop Dilation Operator of N=2 SuperConformal QCD
Liendo, Pedro; Rastelli, Leonardo
2011-01-01
We evaluate the full planar one-loop dilation operator of N=2 SuperConformal QCD, the SU(N_c) super Yang-Mills theory with N_f = 2 N_c fundamental hypermultiplets, in the flavor-singlet sector. Remarkably, the spin-chain Hamiltonian turns out to be completely fixed by superconformal symmetry, as in N=4 SYM. We present a more general calculation, for the superconformal quiver theory with SU(N_c)X SU(N_c) gauge group, which interpolates between N=2 SCQCD and the Z_2 orbifold of N=4 SYM; here symmetry fixes the Hamiltonian up to a single parameter, corresponding to the ratio of the two marginal gauge couplings.
One-loop tests of the supersymmetric higher spin AdS4/CFT3 correspondence
Pang, Yi; Sezgin, Ergin; Zhu, Yaodong
2017-01-01
We compute one-loop free energy for D =4 Vasiliev higher spin gravities based on Konstein-Vasiliev algebras h u (m ;n |4 ) , h o (m ;n |4 ) , or h u s p (m ;n |4 ) and subject to higher spin-preserving boundary conditions, which are conjectured to be dual to the U (N ) , O (N ) or U S p (N ) singlet sectors, respectively, of free conformal field theories (CFTs) on the boundary of AdS4 . Ordinary supersymmetric higher spin theories appear as special cases of Konstein-Vasiliev theories, when the corresponding higher spin algebra contains O S p (N |4 ) as a subalgebra. In AdS4 with an S3 boundary, we use a regularization scheme for individual spins that employs their character such that the subsequent sum over all spins is finite, thereby avoiding the need for additional regularization. We find that the contribution of the infinite tower of bulk fermions vanishes. As a result, the free energy is the sum of those which arise in type A and type B models with internal symmetries, the known mismatch between the bulk and boundary free energies for type B model persists, and ordinary supersymmetric higher spin theories exhibit the mismatch as well. The only models that have a match are type A models with internal symmetries, corresponding to n =0 . The matching requires identification of the inverse Newton constant GN-1 with N plus a proper integer as was found previously for special cases. In AdS4 with an S1×S2 boundary, the bulk one-loop free energies match those of the dual free CFTs for arbitrary m and n . We also show that a supersymmetric double-trace deformation of free CFT based on O S p (1 |4 ) does not contribute to the O (N0) free energy, as expected from the bulk.
One-Loop One-Point Functions in Gauge-Gravity Dualities with Defects
Buhl-Mortensen, Isak; de Leeuw, Marius; Ipsen, Asger C.; Kristjansen, Charlotte; Wilhelm, Matthias
2016-12-01
We initiate the calculation of loop corrections to correlation functions in 4D defect conformal field theories (dCFTs). More precisely, we consider N =4 SYM theory with a codimension-one defect separating two regions of space, x3>0 and x30 . The holographic dual is the D 3 - D 5 probe brane system where the D 5 -brane geometry is AdS4×S2 and a background gauge field has k units of flux through the S2 . We diagonalize the mass matrix of the dCFT making use of fuzzy-sphere coordinates and we handle the x3 dependence of the mass terms in the 4D Minkowski space propagators by reformulating these as standard massive AdS4 propagators. Furthermore, we show that only two Feynman diagrams contribute to the one-loop correction to the one-point function of any single-trace operator and we explicitly calculate this correction in the planar limit for the simplest chiral primary. The result of this calculation is compared to an earlier string-theory computation in a certain double scaling limit and perfect agreement is found. Finally, we discuss how to generalize our calculation to any single-trace operator, to finite N , and to other types of observables such as Wilson loops.
One Loop Tests of Supersymmetric Higher Spin $AdS_4/CFT_3$
Pang, Yi; Zhu, Yaodong
2016-01-01
We compute one loop free energy for D=4 Vasiliev higher spin gravities based on Konstein-Vasiliev algebras hu(m;n|4), ho(m;n|4) or husp(m;n|4) and subject to higher spin preserving boundary conditions, which are conjectured to be dual to the U(N), O(N) or USp(N) singlet sectors, respectively, of free CFTs on the boundary of $AdS_4$. Ordinary supersymmetric higher spin theories appear as special cases of Konstein-Vasiliev theories, when the corresponding higher spin algebra contains $OSp({\\cal N}|4)$ as subalgebra. In $AdS_4$ with $S^3$ boundary, we use a modified spectral zeta function method, which avoids the ambiguity arising from summing over infinite number of spins. We find that the contribution of the infinite tower of bulk fermions vanishes. As a result, the free energy is the sum of those which arise in type A and type B models with internal symmetries, the known mismatch between the bulk and boundary free energies for type B model persists, and ordinary supersymmetric higher spin theories exhibit the...
One-loop one-point functions in AdS/dCFT
Buhl-Mortensen, Isak; Ipsen, Asger C; Kristjansen, Charlotte; Wilhelm, Matthias
2016-01-01
We initiate the calculation of loop corrections to correlation functions in 4D defect CFTs. More precisely, we consider N=4 SYM with a codimension-one defect separating two regions of space, x_3>0 and x_30. The holographic dual is the D3-D5 probe brane system where the D5 brane geometry is AdS_4 x S^2 and a background gauge field has k units of flux through the S^2. We diagonalise the mass matrix of the defect CFT making use of fuzzy-sphere coordinates and we handle the x_3-dependence of the mass terms in the 4D Minkowski space propagators by reformulating these as standard massive AdS_4 propagators. Furthermore, we show that only two Feynman diagrams contribute to the one-loop correction to the one-point function of any single-trace operator and we explicitly calculate this correction in the planar limit for the simplest chiral primary. The result of this calculation is compared to an earlier string-theory computation. Finally, we discuss how to generalise our calculation to any single-trace operator, to fin...
A complete algebraic reduction of one-loop tensor Feynman integrals
Energy Technology Data Exchange (ETDEWEB)
Fleischer, J. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2010-09-15
Guided by the need to eliminate inverse Gram determinants (){sub 5} from tensorial 5-point functions and sub-Gram determinants (){sub 4} from tensorial 4-point functions, we set up a new and very efficient approach for the tensor reduction of Feynman integrals. We eliminate all Gram determinants for one-loop 5-point integrals up to tensors of rank R=5 by reducing their tensor coefficients to higherdimensional 4-point tensor coefficients. These in turn are reduced to expressions which are free of inverse powers of (){sub 4}, but depend on higher-dimensional integrals I{sub 4}{sup (d)} with d{<=}2R. Their expression in terms of scalar integrals defined in the generic dimension, I{sub 4}; I{sub 3}; I{sub 2}; I{sub 1}, however, introduces coefficients [1=(){sub 4}]{sup R} for tensors of rank R. For small or vanishing (){sub 4}, an efficient expansion is found so that a stable numerical evaluation of massive and massless Feynman integrals at arbitrary values of the Gram determinants is made possible. Finally, some relations are mentioned which may be useful for analytic simplifications of the original Feynman diagrams. (orig.)
Delta r in the Two-Higgs-Doublet Model at full one loop level -- and beyond
Lopez-Val, David
2012-01-01
After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The Electroweak parameter Delta r relating the values of the gauge boson masses [MW,MZ] and the Fermi constant [G_F] is the traditional observable encoding high precision information of the electroweak physics at the quantum level. In this work we present a complete quantitative study of Delta r in the framework of the general (unconstrained) Two-Higgs-Doublet Model (2HDM). First of all we report on a systematic analysis of Delta r at the full one loop level in the general 2HDM, which to our knowledge was missing in the literature. Thereby we extract a theoretical prediction for the mass of the W-boson in this model, taking MZ, \\alpha_{em} and G_F as experimental inputs. We find typical corrections leading to mass shifts $\\delta MW \\sim 20-40 MeV$ which help to improve the agreement with the experimentally measured val...
Schabinger, Robert M
2011-01-01
In this paper we discuss in detail computational methods and new results for one-loop virtual corrections to N = 4 super Yang-Mills scattering amplitudes calculated to all orders in epsilon, the dimensional regularization parameter. It is often the case that one-loop gauge theory computations are carried out to order epsilon^0, since higher order in epsilon contributions vanish in the small epsilon limit. We will show, however, that the higher order contributions are actually quite useful. In the context of maximally supersymmetric Yang-Mills, we consider two examples in detail to illustrate our point. First we will concentrate on computations with gluonic external states and argue that N = 4 supersymmetry implies a simple relation between all-orders-in-epsilon one-loop N = 4 super Yang-Mills amplitudes and the first and second stringy corrections to analogous tree-level superstring amplitudes. For our second example we will derive a new result for the all-orders-in-epsilon one-loop superamplitude for planar ...
All Next-to-Maximally-Helicity-Violating One-Loop Gluon Amplitudes in N=4 Super-Yang-Mills Theory
Bern, Z; Kosower, D A; Bern, Zvi; Dixon, Lance J.; Kosower, David A.
2004-01-01
We compute the next-to-MHV one-loop n-gluon amplitudes in N=4 super-Yang-Mills theory. These amplitudes contain three negative-helicity gluons and an arbitrary number of positive-helicity gluons, and are the first infinite series of amplitudes beyond the simplest, MHV, amplitudes. We also discuss some aspects of their twistor-space structure.
One-loop renormalisation of the NMSSM in SloopS : 1. the neutralino-chargino and sfermion sectors
Belanger, G; Boudjema, F; Chalons, G
2016-01-01
We have completed the one-loop renormalisation of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) allowing for and comparing between different renormalisation schemes. A special attention is paid to on-shell schemes. We study a variety of these schemes based on alternative choices of the physical input parameters. In this paper we present our approach to the renormalisation of the NMSSM and report on our results for the neutralino-chargino and sfermion sectors. We will borrow some results from our study of the Higgs sector whose full discussion is left for a separate publication. We have implemented the set up for all the sectors of the NMSSM within \\sloops, a code for the automatic computation of one-loop corrections initially developed for the standard model and the MSSM. Among the many applications that allows the code, we present here the one-loop corrections to neutralino masses and to partial widths of neutralinos and charginos into final states with one gauge boson. One-loop electroweak and Q...
Order 1/N2 test of the Maldacena conjecture : cancellation of the one-loop Weyl anomaly.
Mansfield, Paul; Nolland, David
2000-01-01
We test the Maldacena conjecture for type IIB String Theory/ N=4 Yang-Mills by calculating the one-loop corrections in the bulk theory to the Weyl anomaly of the boundary CFT when the latter is coupled to a Ricci-flat metric. The contributions cancel within each supermultiplet, in agreement with the conjecture.
Avramidi, I G
1994-01-01
We continue the development of the effective covariant methods for calculating the heat kernel and the one-loop effective action in quantum field theory and quantum gravity. The status of the low-energy approximation in quantum gauge theories and quantum gravity is discussed in detail on the basis of analyzing the local Schwinger - De Witt expansion. It is argued that the low-energy limit, when defined in a covariant way, should be related to background fields with covariantly constant curvature, gauge field strength and potential. Some new approaches for calculating the low-energy heat kernel assuming a covariantly constant background are proposed. The one-loop low-energy effective action in Yang-Mills theory in flat space with arbitrary compact simple gauge group and arbitrary matter on a covariantly constant background is calculated. The stability problem of the chromomagnetic (Savvidy-type) vacuum is analyzed. It is shown, that this type of vacuum structure can be stable only in the case when more than on...
String states, loops and effective actions in noncommutative field theory and matrix models
Directory of Open Access Journals (Sweden)
Harold C. Steinacker
2016-09-01
Full Text Available Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
String states, loops and effective actions in noncommutative field theory and matrix models
Energy Technology Data Exchange (ETDEWEB)
Steinacker, Harold C., E-mail: harold.steinacker@univie.ac.at
2016-09-15
Refining previous work by Iso, Kawai and Kitazawa, we discuss bi-local string states as a tool for loop computations in noncommutative field theory and matrix models. Defined in terms of coherent states, they exhibit the stringy features of noncommutative field theory. This leads to a closed form for the 1-loop effective action in position space, capturing the long-range non-local UV/IR mixing for scalar fields. The formalism applies to generic fuzzy spaces. The non-locality is tamed in the maximally supersymmetric IKKT or IIB model, where it gives rise to supergravity. The linearized supergravity interactions are obtained directly in position space at one loop using string states on generic noncommutative branes.
Action orientation overcomes the ego depletion effect.
Dang, Junhua; Xiao, Shanshan; Shi, Yucai; Mao, Lihua
2015-04-01
It has been consistently demonstrated that initial exertion of self-control had negative influence on people's performance on subsequent self-control tasks. This phenomenon is referred to as the ego depletion effect. Based on action control theory, the current research investigated whether the ego depletion effect could be moderated by individuals' action versus state orientation. Our results showed that only state-oriented individuals exhibited ego depletion. For individuals with action orientation, however, their performance was not influenced by initial exertion of self-control. The beneficial effect of action orientation against ego depletion in our experiment results from its facilitation for adapting to the depleting task.
Wilsonian Effective Action of Superstring Theory
Sen, Ashoke
2016-01-01
By integrating out the heavy fields in type II or heterotic string field theory one can construct the effective action for the light fields. This effective theory inherits all the algebraic structures of the parent theory and the effective action automatically satisfies the Batalin-Vilkovisky quantum master equation. This theory is manifestly ultraviolet finite, has only light fields as its explicit degrees of freedom, and the Feynman diagrams of this theory reproduce the exact scattering amplitudes of light states in string theory to any arbitrary order in perturbation theory. Furthermore in this theory the degrees of freedom of light fields above certain energy scale are also implicitly integrated out. This energy scale is determined by a particular parameter labelling a family of equivalent actions, and can be made arbitrarily low, leading to the interpretation of the effective action as the Wilsonian effective action.
Wilsonian effective action of superstring theory
Sen, Ashoke
2017-01-01
By integrating out the heavy fields in type II or heterotic string field theory one can construct the effective action for the light fields. This effective theory inherits all the algebraic structures of the parent theory and the effective action automatically satisfies the Batalin-Vilkovisky quantum master equation. This theory is manifestly ultraviolet finite, has only light fields as its explicit degrees of freedom, and the Feynman diagrams of this theory reproduce the exact scattering amplitudes of light states in string theory to any arbitrary order in perturbation theory. Furthermore in this theory the degrees of freedom of light fields above certain energy scale are also implicitly integrated out. This energy scale is determined by a particular parameter labelling a family of equivalent actions, and can be made arbitrarily low, leading to the interpretation of the effective action as the Wilsonian effective action.
Vacuum effective action: semiclassical approach
Energy Technology Data Exchange (ETDEWEB)
Shapiro, I L [Departamento de Fisica, ICE, Universidade Federal de Juiz de Fora, MG (Brazil)
2007-11-15
We present a brief review of quantum corrections to the action of gravity. The main attention is concentrated on the quantum theory of matter fields (QFT) on classical metric background. The list of most interesting possible applications of quantum corrections includes inflation and the Dark Energy problem. We show that both problems can be, in principle, resolved within the semiclassical theory, without invoking quantum gravity or string theory.
Non-Zero Magnetic Screening Mass in QED and QCD at One Loop Level in Non-Equilibrium
Cooper, F; Nayak, G C; Cooper, Fred; Kao, Chung-Wen; Nayak, Gouranga C.
2002-01-01
Using the Schwinger-Keldysh closed time path integral formalism we show that the magnetic screening mass in QED and QCD at one loop level is non-zero as long as the single particle distribution function f(\\vec{k}) is non-isotropic, {i.e.} it depends on the direction of the momentum. For isotropic distribution functions such as those corresponding to thermal equilibrium the magnetic screening mass at one loop level is found to be zero which is consistent with finite temperature field theory. The non-zero magnetic screening mass in non-isotropic non-equlibrium situations has fundamental importance in that it acts as a natural cut-off to remove infrared divergences in the magnetic sector. Thus it allows one to avoid infrared problems which previously made it difficult to use a transport theory approach using perturbative QCD or QED scattering kernels to study the thermalization of a QED or QCD plasma.
Lattice Wess-Zumino model with Ginsparg-Wilson fermions: One-loop results and GPU benchmarks
Chen, Chen; Giedt, Joel
2010-01-01
We numerically evaluate the one-loop counterterms for the four-dimensional Wess-Zumino model formulated on the lattice using Ginsparg-Wilson fermions of the overlap (Neuberger) variety, such that a lattice version of U(1)_R symmetry is exactly preserved in the limit of vanishing bare mass. We confirm previous findings by other authors that at one loop there is no renormalization of the superpotential in the lattice theory. We discuss aspects of the simulation of this model that is planned for a follow-up work, and outline a strategy for nonperturbative improvement of the lattice supercurrent through measurements of \\susy\\ Ward identities. Related to this, some benchmarks for our graphics processing unit code are provided. An initial simulation finds a nearly vanishing vacuum expectation value for the auxiliary field, consistent with approximate supersymmetry.
Alexandrou, C; Panagopoulos, H; Vicari, E
2000-01-01
We compute the ratio between the scale $\\Lambda_L$ associated with a lattice formulation of QCD using the overlap-Dirac operator, and $\\Lambda_{MS-bar}$. To this end, the one-loop relation between the lattice coupling $g_0$ and the coupling renormalized in the MS-bar scheme is calculated, using the lattice background field technique. We also compute the one-loop renormalization $Z_\\Gamma$ of the two-quark operators $\\bar{\\psi} \\Gamma \\psi$, where $\\Gamma$ denotes a generic Dirac matrix. Furthermore, we study the renormalization of quark bilinears which are more extended and have better chiral properties. Finally, we present improved estimates of $Z_\\Gamma$, coming from cactus resummation and from mean field perturbation theory.
One-loop amplitudes of winding strings in AdS$_3$ and the Coulomb gas approach
Giribet, Gaston
2015-01-01
We discuss a Coulomb gas realization of $n$-point correlation functions in the $SL(2,\\mathbb{R})$ Wess-Zumino-Witten (WZW) model that is suitable to compute scattering amplitudes of winding strings in 3-dimensional Anti-de Sitter space at tree-level and one-loop. This is a refined version of previously proposed free-field realizations that, among other features, accomplishes to make the $H_3^+$ WZW-Liouville correspondence manifest.
Indian Academy of Sciences (India)
S SOMORENDRO SINGH; G SAXENA
2017-06-01
We calculate quark number density and susceptibility under one-loop correction in the mean-field potential. The calculation shows continuous increase in the number density and susceptibility up to the temperature $T = 0.4 \\rm{GeV}$. Then the values of number density and susceptibility approach the very weakly result with higher values of temperature. The result indicates that the calculated values fit well with increase in temperature to match the lattice QCD simulations of the same quantities.
Ibarra, Alejandro
2015-01-01
We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark ...
Energy Technology Data Exchange (ETDEWEB)
Ibarra, Alejandro; Wild, Sebastian [Physik-Department T30d, Technische Universität München, James-Franck-Straße, 85748 Garching (Germany)
2015-05-26
We analyze the direct detection signals of a toy model consisting of a Dirac dark matter particle which couples to one Standard Model fermion via a scalar mediator. For all scenarios, the dark matter particle scatters off nucleons via one loop-induced electromagnetic and electroweak moments, as well as via the one-loop exchange of a Higgs boson. Besides, and depending on the details of the model, the scattering can also be mediated at tree level via the exchange of the scalar mediator or at one loop via gluon-gluon interactions. We show that, for thermally produced dark matter particles, the current limits from the LUX experiment on these scenarios are remarkably strong, even for dark matter coupling only to leptons. We also discuss future prospects for XENON1T and DARWIN and we argue that multi-ton xenon detectors will be able to probe practically the whole parameter space of the model consistent with thermal production and perturbativity. We also discuss briefly the implications of our results for the dark matter interpretation of the Galactic GeV excess.
Cui, Jian-Wei; Ma, Yong-Liang; Wu, Yue-Liang
2011-07-01
The QED trace anomaly is calculated at one-loop level based on the loop regularization method which is realized in 4-dimensional space-time and preserves gauge symmetry and Poincaré symmetry in spite of the introduction of two mass scales, namely, the ultraviolet (UV) cutoff Mc and infrared (IR) cutoff μs. It is shown that the dilation Ward identity which relates the three-point diagrams with the vacuum polarization diagrams gets the standard form of trace anomaly through quantum corrections in taking the consistent limit Mc→∞ and μs=0 which recovers the original integrals. This explicitly demonstrates that the loop regularization method is indeed a self-consistent regularization scheme which is applicable to the calculations not only for the chiral anomaly but also for the trace anomaly, at least at one-loop level. It is also seen that the consistency conditions which relate the tensor-type and scalar-type irreducible loop integrals (ILIs) are crucial for obtaining a consistent result. As a comparison, we also present the one-loop calculations by using the usual Pauli-Villars regularization and the dimensional regularization.
The Gospel according to DeWitt revisited: quantum effective action in braneworld models
Barvinsky, A O
2005-01-01
We construct quantum effective action in spacetimes with branes (boundaries) and establish its relation to the "cosmological wave function" of the bulk -- the solution of the corresponding Wheeler-DeWitt equation which can be considered as a means of the holographic description of braneworld models. We show that for a special type of the bulk-brane gauge fixing procedure the one-loop part of the action decouples into the additive sum of brane-to-brane and bulk-to-bulk effective actions, and this decomposition proliferates in a special way in higher orders of the Feynman diagrammatic expansion. This property is based on a special duality relation between the Dirichlet and Neumann boundary value problems when applied to the functional determinants of wave operators and the field-theoretic version of the well-known semiclassical Van Vleck-Morette determinant. It facilitates the gauge-independent way of treating the strong-coupling and VDVZ problems in brane induced gravity models. Importance of this technique in...
Supersymmetric action of multiple D0-branes from matrix theory
Energy Technology Data Exchange (ETDEWEB)
Asano, Masako E-mail: asano@post.kek.jp; Sekino, Yasuhiro E-mail: sekino@th.phys.titech.ac.jp
2002-11-11
We study one-loop effective action of Berkooz-Douglas matrix theory and obtain non-Abelian action of D0-branes in the longitudinal 5-brane background. In this paper, we extend the analysis of hep-th/0201248 and calculate the part of the effective action containing fermions. We show that the effective action is manifestly invariant under the loop-corrected SUSY transformation, and give the explicit transformation laws. The effective action consists of blocks which are closed under the SUSY, and it includes the supersymmetric completion of the couplings to the longitudinal 5-branes proposed by Taylor and Van Raamsdonk as a subset.
Complex Effective Action and Schwinger Effect
Kim, Sang Pyo
2016-01-01
Spontaneous pair production from background fields or spacetimes is one of the most prominent phenomena predicted by quantum field theory. The Schwinger mechanism of production of charged pairs by a strong electric field and the Hawking radiation of all species of particles from a black hole are the consequence of nonperturbative quantum effects. In this review article, the vacuum structure and pair production is reviewed in the in-out formalism, which provides a consistent framework for quantum field theory in the sense that the complex action explains not only the vacuum persistence but also pair production. The current technology of intense lasers is still lower by a few order than the Schwinger limit for electron-positron pair production, while magnetic fields of magnetars on the surface are higher than the Schwinger limit and even higher at the core. On the other hand, the zero effective mass of electron and hole in graphene and Dirac or Weyl semimetals will open a window for experimental test of quantum...
Euler-Heisenberg-Weiss action for QCD+QED
Ozaki, Sho; Hattori, Koichi; Itakura, Kazunori
2015-01-01
We derive an analytic expression for one-loop effective action of QCD+QED at zero and finite temperatures by using the Schwinger's proper time method. The result is a nonlinear effective action not only for electromagnetic and chromo-electromagnetic fields but also the Polyakov loop, and thus reproduces the Euler-Heisenberg action in QED, QCD, and QED+QCD, and also the Weiss potential for the Polyakov loop at finite temperature. As applications of this "Euler-Heisenberg-Weiss" action in QCD+QED, we investigate quark pair productions induced by QCD+QED fields at zero temperature and the Polyakov loop in the presence of strong electromagnetic fields. Quark one-loop contribution to the effective potential of the Polyakov loop explicitly breaks the center symmetry, and is found to be enhanced by the magnetic field, which is consistent with the inverse magnetic catalysis observed in lattice QCD simulation.
Gauge Coupling Field, Currents, Anomalies and N=1 Super-Yang-Mills Effective Actions
Ambrosetti, Nicola; Derendinger, Jean-Pierre; Hartog, Jelle
2016-01-01
Working with a gauge coupling field in a linear superfield, we construct effective Lagrangians for N=1 super-Yang-Mills theory fully compatible with the expected all-order behaviour or physical quantities. Using the one-loop dependence on its ultraviolet cutoff and anomaly matching or cancellation of R and dilatation anomalies, we obtain the Wilsonian effective Lagrangian. With similar anomaly matching or cancellation methods, we derive the effective action for gaugino condensates, as a function of the real coupling field. Both effective actions lead to a derivation of the NSVZ beta function from algebraic arguments only. The extension of results to N=2 theories or to matter systems is briefly considered. The main tool for the discussion of anomalies is a generic supercurrent structure with 16_B+16_F operators (the S multiplet), which we derive using superspace identities and field equations for a fully general gauge theory Lagrangian with the linear gauge coupling superfield, and with various U(1)_R currents...
Gauge coupling field, currents, anomalies and N=1 super-Yang–Mills effective actions
Directory of Open Access Journals (Sweden)
Nicola Ambrosetti
2017-02-01
Full Text Available Working with a gauge coupling field in a linear superfield, we construct effective Lagrangians for N=1 super-Yang–Mills theory fully compatible with the expected all-order behavior or physical quantities. Using the one-loop dependence on its ultraviolet cutoff and anomaly matching or cancellation of R and dilatation anomalies, we obtain the Wilsonian effective Lagrangian. With similar anomaly matching or cancellation methods, we derive the effective action for gaugino condensates, as a function of the real coupling field. Both effective actions lead to a derivation of the NSVZ β function from algebraic arguments only. The extension of results to N=2 theories or to matter systems is briefly considered. The main tool for the discussion of anomalies is a generic supercurrent structure with 16B+16F operators (the S multiplet, which we derive using superspace identities and field equations for a fully general gauge theory Lagrangian with the linear gauge coupling superfield, and with various U(1R currents. As a byproduct, we show under which conditions the S multiplet can be improved to contain the Callan–Coleman–Jackiw energy-momentum tensor whose trace measures the breaking of scale invariance.
Gauge coupling field, currents, anomalies and N = 1 super-Yang-Mills effective actions
Ambrosetti, Nicola; Arnold, Daniel; Derendinger, Jean-Pierre; Hartong, Jelle
2017-02-01
Working with a gauge coupling field in a linear superfield, we construct effective Lagrangians for N = 1 super-Yang-Mills theory fully compatible with the expected all-order behavior or physical quantities. Using the one-loop dependence on its ultraviolet cutoff and anomaly matching or cancellation of R and dilatation anomalies, we obtain the Wilsonian effective Lagrangian. With similar anomaly matching or cancellation methods, we derive the effective action for gaugino condensates, as a function of the real coupling field. Both effective actions lead to a derivation of the NSVZ β function from algebraic arguments only. The extension of results to N = 2 theories or to matter systems is briefly considered. The main tool for the discussion of anomalies is a generic supercurrent structure with 16B +16F operators (the S multiplet), which we derive using superspace identities and field equations for a fully general gauge theory Lagrangian with the linear gauge coupling superfield, and with various U(1)R currents. As a byproduct, we show under which conditions the S multiplet can be improved to contain the Callan-Coleman-Jackiw energy-momentum tensor whose trace measures the breaking of scale invariance.
Effective supergravity actions for conifold transitions
Energy Technology Data Exchange (ETDEWEB)
Mohaupt, Thomas; Saueressig, Frank E-mail: F.S.Saueressig@phys.uu.nl
2005-03-01
We construct gauged supergravity actions which describe the dynamics of M-theory on a Calabi-Yau threefold in the vicinity of a conifold transition. The actions explicitly include N charged hypermultiplets descending from wrapped M2-branes which become massless at the conifold point. While the vector multiplet sector can be treated exactly, we approximate the hypermultiplet sector by the non-compact Wolf spaces X(1+N). The effective action is then uniquely determined by the charges of the wrapped M2-branes. (author)
QED effective action for an O(2)xO(3) symmetric field in the full mass range
Ahmadiniaz, N; Raya, A; Schubert, C
2013-01-01
An interesting class of background field configurations in QED are the O(2)xO(3) symmetric fields. Those backgrounds have some instanton-like properties and yield a one-loop effective action that is highly nontrivial but amenable to numerical calculation, for both scalar and spinor QED. Here we use the recently developed "partial-wave-cutoff method" for a numerical analysis of both effective actions in the full mass range. In particular, at large mass we are able to match the asymptotic behavior of the physically renormalized effective action against the leading two mass levels of the inverse mass (or heat kernel) expansion. At small mass we obtain good numerical results even in the massless case for the appropriately (unphysically) renormalized effective action after the removal of the chiral anomaly term through a small radial cutoff factor. In particular, we show that the effective action after this removal remains finite in the massless limit, which also provides indirect support for M. Fry's hypothesis t...
HFOLD - A program package for calculating two-body MSSM Higgs decays at full one-loop level.
Frisch, W; Eberl, H; Hluchá, H
2011-10-01
HFOLD (Higgs Full One Loop Decays) is a Fortran program package for calculating all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The package is done in the SUSY Parameter Analysis convention and supports the SUSY Les Houches Accord input and output format. PROGRAM SUMMARY: Program title: HFOLD Catalogue identifier: AEJG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 340 621 No. of bytes in distributed program, including test data, etc.: 1 760 051 Distribution format: tar.gz Programming language: Fortran 77 Computer: Workstation, PC Operating system: Linux RAM: 524 288 000 Bytes Classification: 11.1 External routines: LoopTools 2.2 (http://www.feynarts.de/looptools/), SLHALib 2.2 (http://www.feynarts.de/slha/). The LoopTools code is included in the distribution package. Nature of problem: A future high-energy e+e- linear collider will be the best environment for the precise measurements of masses, cross sections, branching ratios, etc. Experimental accuracies are expected at the per-cent down to the per-mile level. These must be matched from the theoretical side. Therefore higher order calculations are mandatory. Solution method: This program package calculates all MSSM Higgs two-body decay widths and the corresponding branching ratios at full one-loop level. The renormalization is done in the DR scheme following the SUSY Parameter Analysis convention. The program supports the SUSY Les Houches Accord input and output format. Running time: The example provided takes only a few seconds to run.
Action-based effects on music perception
Directory of Open Access Journals (Sweden)
Pieter-Jan eMaes
2014-01-01
Full Text Available The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral phenomena. In contrast, embodied accounts to music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework capturing the ways that the human motor system, and the actions it produces, can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modelling, and vice versa, to predict the sensory outcomes of planned actions (forward modelling. Embodied accounts typically adhere to inverse modelling to explain action effects on music perception (Leman, 2007. We extent this account by pinpointing forward modelling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system, and the action it produces, suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music cognition in the sense that it needs to be considered as a dynamic process, in which aspects of action, perception, introspection, and social interaction are of crucial
Action-based effects on music perception
Maes, Pieter-Jan; Leman, Marc; Palmer, Caroline; Wanderley, Marcelo M.
2013-01-01
The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral processes. In contrast, embodied accounts of music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework that captures the ways in which the human motor system and its actions can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory, postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modeling), and vice versa, to predict the sensory outcomes of planned actions (forward modeling). Embodied accounts typically refer to inverse modeling to explain action effects on music perception (Leman, 2007). We extend this account by pinpointing forward modeling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system and its actions suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music) cognition in the sense that it needs to be considered as a dynamical process, in which aspects of action, perception, introspection, and social interaction are of crucial importance. PMID:24454299
Package-X 2.0: A Mathematica package for the analytic calculation of one-loop integrals
Patel, Hiren H.
2017-09-01
This article summarizes new features and enhancements of the first major update of Package-X. Package-X 2.0 can now generate analytic expressions for arbitrarily high rank dimensionally regulated tensor integrals with up to four distinct propagators, each with arbitrary integer weight, near an arbitrary even number of spacetime dimensions, giving UV divergent, IR divergent, and finite parts at (almost) any real-valued kinematic point. Additionally, it can generate multivariable Taylor series expansions of these integrals around any non-singular kinematic point to arbitrary order. All special functions and abbreviations output by Package-X 2.0 support Mathematica's arbitrary precision evaluation capabilities to deal with issues of numerical stability. Finally, tensor algebraic routines of Package-X have been polished and extended to support open fermion chains both on and off shell. The documentation (equivalent to over 100 printed pages) is accessed through Mathematica's Wolfram Documentation Center and contains information on all Package-X symbols, with over 300 basic usage examples, 3 project-scale tutorials, and instructions on linking to FEYNCALC and LOOPTOOLS. Program files doi:http://dx.doi.org/10.17632/yfkwrd4d5t.1 Licensing provisions: CC by 4.0 Programming language: Mathematica (Wolfram Language) Journal reference of previous version: H. H. Patel, Comput. Phys. Commun 197, 276 (2015) Does the new version supersede the previous version?: Yes Summary of revisions: Extension to four point one-loop integrals with higher powers of denominator factors, separate extraction of UV and IR divergent parts, testing for power IR divergences, construction of Taylor series expansions of one-loop integrals, numerical evaluation with arbitrary precision arithmetic, manipulation of fermion chains, improved tensor algebraic routines, and much expanded documentation. Nature of problem: Analytic calculation of one-loop integrals in relativistic quantum field theory. Solution
Action-effect bindings and ideomotor learning in intention- and stimulus-based actions
Directory of Open Access Journals (Sweden)
Arvid eHerwig
2012-10-01
Full Text Available According to ideomotor theory, action-effect associations are crucial for voluntary action control. Recently, a number of studies started to investigate the conditions that mediate the acquisition and application of action-effect associations by comparing actions carried out in response to exogenous stimuli (stimulus-based with actions selected endogenously (intention-based. There is evidence that the acquisition and/or application of action-effect associations is boosted when acting in an intention-based action mode. For instance, bidirectional action-effect associations were diagnosed in a forced choice test phase if participants previously experienced action-effect couplings in an intention-based but not in a stimulus-based action mode. The present study aims at investigating effects of the action mode on action-effect associations in more detail. In a series of experiments, we compared the strength and durability of short-term action-effect associations (binding immediately following intention- as well as stimulus-based actions. Moreover, long-term action-effect associations (learning were assessed in a subsequent test phase. Our results show short-term action-effect associations of equal strength and durability for both action modes. However, replicating previous results, long-term associations were observed only following intention-based actions. These findings indicate that the effect of the action mode on long-term associations cannot merely be a result of accumulated short-term action-effect bindings. Instead, only those episodic bindings are selectively perpetuated or retrieved that integrate action-relevant aspects of the processing event, i.e., in case of intention-based actions, the link between action and ensuing effect.
Tsoupros, G
2000-01-01
The effect of quantum corrections to a conformally invariant field theory for a self-interacting scalar field on a curved manifold with boundary is considered. The analysis is most easily performed in a space of constant curvature the boundary of which is characterised by constant extrinsic curvature. An extension of the spherical formulation in the presence of a boundary is attained through use of the method of images. Contrary to the consolidated vanishing effect in maximally symmetric space-times the contribution of the massless "tadpole" diagram no longer vanishes in dimensional regularisation. As a result, conformal invariance is broken due to boundary-related vacuum contributions. The evaluation of one-loop contributions to the two-point function suggests an extension, in the presence of matter couplings, of the simultaneous volume and boundary renormalisation in the effective action.
One-loop transition amplitudes in the D1D5 CFT
Carson, Zaq; Hampton, Shaun; Mathur, Samir D.
2017-01-01
We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed off the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. We consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coefficients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are taken to be much larger than unity. We also prove a number of useful relationships valid for processes with an arbitrary number of twist insertions.
One-Loop Transition Amplitudes in the D1D5 CFT
Carson, Zaq; Mathur, Samir D
2016-01-01
We consider the issue of thermalization in the D1D5 CFT. Thermalization is expected to correspond to the formation of a black hole in the dual gravity theory. We start from the orbifold point, where the theory is essentially free, and does not thermalize. In earlier work it was noted that there was no clear thermalization effect when the theory was deformed off the orbifold point to first order in the relevant twist perturbation. In this paper we consider the deformation to second order in the twist, where we do find effects that can cause thermalization of an initial perturbation. We consider a 1-loop process where two untwisted copies of the CFT are twisted to one copy and then again untwisted to two copies. We start with a single oscillator excitation on the initial CFT, and compute the effect of the two twists on this state. We find simple approximate expressions for the Bogoliubov coefficients and the behavior of the single oscillator excitation in the continuum limit, where the mode numbers involved are...
Energy Technology Data Exchange (ETDEWEB)
Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Zurich Univ. (Switzerland). Inst. for Theoretical Physics; Smith, Robert E. [Zurich Univ. (Switzerland). Inst. for Theoretical Physics
2009-10-15
We generalize the ''renormalized'' perturbation theory (RPT) formalism of M. Crocce and R. Scoccimarro (2006) to deal with multiple fluids in the Universe and here we present the complete calculations up to the one-loop level in the RPT. We apply this approach to the problem of following the nonlinear evolution of baryon and cold dark matter (CDM) perturbations, evolving from the distinct sets of initial conditions, from the high redshift post-recombination Universe right through to the present day. In current theoretical and numerical models of structure formation, it is standard practice to treat baryons and CDM as an effective single matter fluid - the so called dark matter only modeling. In this approximation, one uses a weighed sum of late time baryon and CDM transfer functions to set initial mass fluctuations. In this paper we explore whether this approach can be employed for high precision modeling of structure formation. We show that, even if we only follow the linear evolution, there is a large-scale scale-dependent bias between baryons and CDM for the currently favored WMAP5 {lambda}CDM model. This time evolving bias is significant (> 1%) until the present day, when it is driven towards unity through gravitational relaxation processes. Using the RPT formalism we test this approximation in the non-linear regime. We show that the non-linear CDM power spectrum in the 2-component fluid differs from that obtained from an effective mean-mass 1-component fluid by {proportional_to} 3% on scales of order k {proportional_to} 0.05 h Mpc{sup -1} at z = 10, and by {proportional_to} 0.5% at z = 0. However, for the case of the non-linear evolution of the baryons the situation is worse and we find that the power spectrum is suppressed, relative to the total matter, by {proportional_to} 15% on scales k {proportional_to} 0.05 hMpc{sup -1} at z = 10, and by {proportional_to} 3 - 5% at z = 0. Importantly, besides the suppression of the spectrum, the
The one-loop elastic coefficients for the Helfrich membrane in higher dimensions
Energy Technology Data Exchange (ETDEWEB)
Santiago, J A [Centro de Investigacion Avanzada en Ingenieria Industrial, Universidad Autonoma del Estado de Hidalgo, Pachuca 42090 (Mexico); Zamora, A [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico DF 04510 (Mexico)
2005-02-11
Using a covariant geometric approach we obtain the effective bending couplings for a two-dimensional rigid membrane embedded into a (2 + D)-dimensional Euclidean space. The Hamiltonian for the membrane has three terms: the first one is quadratic in its mean extrinsic curvature. The second one is proportional to its Gaussian curvature and the last one is proportional to its area. The results we obtain are in agreement with those finding that thermal fluctuations soften the two-dimensional membrane embedded into a three-dimensional Euclidean space.
Lattice Wess-Zumino model with Ginsparg-Wilson fermions: One-loop results and GPU benchmarks
Chen, Chen; Dzienkowski, Eric; Giedt, Joel
2010-10-01
We numerically evaluate the one-loop counterterms for the four-dimensional Wess-Zumino model formulated on the lattice using Ginsparg-Wilson fermions of the overlap (Neuberger) variety, together with an auxiliary fermion (plus superpartners), such that a lattice version of U(1)R symmetry is exactly preserved in the limit of vanishing bare mass. We confirm previous findings by other authors that at one loop there is no renormalization of the superpotential in the lattice theory, but that there is a mismatch in the wave-function renormalization of the auxiliary field. We study the range of the Dirac operator that results when the auxiliary fermion is integrated out, and show that localization does occur, but that it is less pronounced than the exponential localization of the overlap operator. We also present preliminary simulation results for this model, and outline a strategy for nonperturbative improvement of the lattice supercurrent through measurements of supersymmetry Ward identities. Related to this, some benchmarks for our graphics processing unit code are provided. Our simulation results find a nearly vanishing vacuum expectation value for the auxiliary field, consistent with approximate supersymmetry at weak coupling.
Bélanger, G; Fujimoto, J; Ishikawa, T; Kaneko, T; Kato, K; Shimizu, Y
2003-01-01
A general non-linear gauge condition is implemented into GRACE, an automated system for the calculation of physical processes in high-energy physics. These new gauge-fixing conditions are used as a very efficient means to check the results of large scale automated computation in the standard model. We describe in detail the implementation of the general gauge condition and the renormalisation procedure at one-loop in the standard model. Explicit formulae for all two-point functions in a generalised non-linear gauge are given, together with the complete set of counterterms. We also show how infrared divergences are dealt with in the system. A new technique for the reduction of the tensor integrals is described. We give a comprehensive presentation of some systematic test-runs which have been performed at the one-loop level for a wide variety of two-to-two processes to show the validity of the gauge check. These cover fermion-fermion scattering, gauge boson scattering into fermions, gauge bosons and Higgs boson...
A recursive method to calculate UV-divergent parts at one-loop level in dimensional regularization
Feng, Feng
2012-07-01
A method is introduced to calculate the UV-divergent parts at one-loop level in dimensional regularization. The method is based on the recursion, and the basic integrals are just the scaleless integrals after the recursive reduction, which involve no other momentum scales except the loop momentum itself. The method can be easily implemented in any symbolic computer language, and a implementation in MATHEMATICA is ready to use. Catalogue identifier: AELY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AELY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 26 361 No. of bytes in distributed program, including test data, etc.: 412 084 Distribution format: tar.gz Programming language: Mathematica Computer: Any computer where the Mathematica is running. Operating system: Any capable of running Mathematica. Classification: 11.1 External routines: FeynCalc (http://www.feyncalc.org/), FeynArts (http://www.feynarts.de/) Nature of problem: To get the UV-divergent part of any one-loop expression. Solution method: UVPart is a Mathematica package where the recursive method has been implemented. Running time: In general it is below one second.
Charged Higgs Boson Production at e+e- Colliders in the Complex MSSM: A Full One-Loop Analysis
Heinemeyer, S
2016-01-01
For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector precise knowledge of their production properties is mandatory. We evaluate the cross sections for the charged Higgs boson production at e+e- colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanism e+e- -> H+H- and e+e- -> H^\\pm W^\\mp, including soft and hard QED radiation. The dependence of the Higgs boson production cross sections on the relevant cMSSM parameters is analyzed numerically. We find sizable contributions to many cross sections. They are, depending on the production channel, roughly of 5-10% of the tree-level results, but can go up to 20% or higher. The full one-loop contributions are important for a future linear e+e- collider such as the ILC or CLIC.
Ding, Mingnan; Lu, Bing-Sui; Xing, Xiangjun
2016-10-01
Self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a m :-n electrolyte. A perturbation series is developed in terms of g =4 π κ b , where b a n d 1 /κ are Bjerrum length and bare Debye length, respectively. To the zeroth order, we obtain the nonlinear Poisson-Boltzmann theory. For asymmetric electrolytes (m ≠n ), the first order (one-loop) correction to mean potential contains a secular term, which indicates the breakdown of the regular perturbation method. Using a renormalizaton group transformation, we remove the secular term and obtain a globally well-behaved one-loop approximation with a renormalized Debye length and a renormalized surface charge density. Furthermore, we find that if the counterions are multivalent, the surface charge density is renormalized substantially downwards and may undergo a change of sign, if the bare surface charge density is sufficiently large. Our results agrees with large MC simulation even when the density of electrolytes is relatively high.
Higgs windows to new physics through d = 6 operators: Constraints and one-loop anomalous dimensions
Elias-Miro, J; Masso, E; Pomarol, A
2013-01-01
The leading contributions from heavy new physics to Higgs processes can be captured in a model-independent way by dimension-six operators in an effective Lagrangian approach. We present a complete analysis of how these contributions affect Higgs couplings. Under certain well-motivated assumptions, we find that 8 CP-even plus 3 CP-odd Wilson coefficients parametrize the main impact in Higgs physics, as all other coefficients are constrained by non-Higgs SM measurements. We calculate the most relevant anomalous dimensions for these Wilson coefficients, which describe operator mixing from the heavy scale down to the electroweak scale. This allows us to find the leading-log corrections to the predictions for the Higgs couplings in specific models, such as the MSSM or composite Higgs, which we find to be significant in certain cases.
One-Loop Radiative Correction to the Triple Higgs Coupling in the Higgs Singlet Model
He, Shi-Ping
2016-01-01
Though the 125 GeV Higgs boson is consistent with the standard model (SM) prediction until now, the triple coupling can deviate from the SM value in the physics beyond the SM (BSM). In this paper, the radiative correction to the triple Higgs coupling is calculated in the minimal extension of the SM by adding a real gauge singlet scalar. In this model there are two scalars $h$ and $H$ and both of them are mixed states of the doublet and singlet. Provided that the mixing angle is set to be zero, $h$ is the pure left-over of the doublet and its behavior is the same as that of the SM except the triple $h$ couping. In this SM limit case, the effect of the singlet $H$ will decouple from the fermions and gauge bosons, and firstly shown up in the triple $h$ coupling. Our numerical results show that the deviation is sizable. For $\\lambda_{\\Phi{S}}=1$ (see text for the parameter definition), the deviation $\\delta_{hhh}^{(1)}$ can be $40\\%$. For $\\lambda_{\\Phi{S}}=1.5$, the $\\delta_{hhh}^{(1)}$ can reach $140\\%$. The si...
One-loop radiative correction to the triple Higgs coupling in the Higgs singlet model
He, Shi-Ping; Zhu, Shou-hua
2017-01-01
Though the 125 GeV Higgs boson is consistent with the standard model (SM) prediction until now, the triple Higgs coupling can deviate from the SM value in the physics beyond the SM (BSM). In this paper, the radiative correction to the triple Higgs coupling is calculated in the minimal extension of the SM by adding a real gauge singlet scalar. In this model there are two scalars h and H and both of them are mixing states of the doublet and singlet. Provided that the mixing angle is set to be zero, namely the SM limit, h is the pure left-over of the doublet and its behavior is the same as that of the SM at the tree level. However the loop corrections can alter h-related couplings. In this SM limit case, the effect of the singlet H may show up in the h-related couplings, especially the triple h coupling. Our numerical results show that the deviation is sizable. For λΦS = 1 (see text for the parameter definition), the deviation δhhh(1) can be 40%. For λΦS = 1.5, the δhhh(1) can reach 140%. The sizable radiative correction is mainly caused by three reasons: the magnitude of the coupling λΦS, light mass of the additional scalar and the threshold enhancement. The radiative corrections for the hVV, hff couplings are from the counter-terms, which are the universal correction in this model and always at O(1%). The hZZ coupling, which can be precisely measured, may be a complementarity to the triple h coupling to search for the BSM. In the optimal case, the triple h coupling is very sensitive to the BSM physics, and this model can be tested at future high luminosity hadron colliders and electron-positron colliders.
Effective action for strongly correlated electron systems
Energy Technology Data Exchange (ETDEWEB)
Ferraz, A., E-mail: aferraz.iccmp@gmail.com [International Institute of Physics - UFRN, Department of Experimental and Theoretical Physics - UFRN, Natal (Brazil); Kochetov, E.A. [International Institute of Physics - UFRN, Natal (Brazil); Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)
2011-12-21
The su(2|1) coherent-state path-integral representation of the partition function of the t-J model of strongly correlated electrons is derived at finite doping. The emergent effective action is compared to the one proposed earlier on phenomenological grounds by Shankar to describe holes in an antiferromagnet [R. Shankar, Nucl. Phys. B 330 (1990) 433]. The t-J model effective action is found to have an important 'extra' factor with no analogue in Shankar's action. It represents the local constraint of no double electron occupancy and reflects the rearrangement of the underlying phase-space manifold due to the presence of strong electron correlation. This important ingredient is shown to be essential to describe the physics of strongly correlated electron systems.
(-)-Carvone: antispasmodic effect and mode of action.
Souza, Fábia Valéria M; da Rocha, Marcelly Barbosa; de Souza, Damião P; Marçal, Rosilene Moretti
2013-03-01
(-)-Carvone is a monoterpene ketone found in spearmint (Mentha spicata var. crispa) essential oil that is widely used as an odor and flavor additive. An intestinal antispasmodic effect was recently reported for (-)-carvone, and it has been shown to be more potent than its (+)-antipode. The mechanism of (-)-carvone action in the intestines has not been investigated. To gain a better understanding of the (-)-carvone antispasmodic effect, we investigated its pharmacological effects in the guinea pig ileum. Terminal portions of the ileum were mounted for isotonic contraction recordings. The effect of (-)-carvone was compared with that of the classical calcium channel blocker (CCB) verapamil. In isolated ileal smooth muscle, (-)-carvone did not produce direct contractile or relaxation responses and did not modify electrically elicited contractions or low K(+)-evoked contractions. The submaximal contractions induced by histamine (p<0.001), BaCl2 (p<0.05), and carbachol (p<0.01) were significantly reduced by (-)-carvone. The contractile response elicited by high concentrations of carbachol was reduced but not abolished by (-)-carvone. No additive action was detected with co-incubation of (-)-carvone and verapamil on carbachol-induced contraction. (-)-Carvone reduced the contraction induced by high K(+) and was almost 100 times more potent than verapamil. Thus, (-)-carvone showed a typical and potent CCB-like action. Many effects described for both (-)-carvone and spearmint oil can be explained as a CCB-like mode of action.
Institute of Scientific and Technical Information of China (English)
SUN Yi; CHANG Hao-Ran
2012-01-01
By further examining the symmetry of external momenta and masses in Feynman integrals,we fulfilled the method proposed by Battistel and Dallabona,and showed that recursion relations in this method can be applied to simplify Feynman integrals directly.
One-loop Wilson loops and the particle-interface potential in AdS/dCFT
Directory of Open Access Journals (Sweden)
Marius de Leeuw
2017-05-01
Full Text Available We initiate the calculation of quantum corrections to Wilson loops in a class of four-dimensional defect conformal field theories with vacuum expectation values based on N=4 super Yang–Mills theory. Concretely, we consider an infinite straight Wilson line, obtaining explicit results for the one-loop correction to its expectation value in the large-N limit. This allows us to extract the particle-interface potential of the theory. In a further double-scaling limit, we compare our results to those of a previous calculation in the dual string-theory set-up consisting of a D5-D3 probe-brane system with flux, and we find perfect agreement.
Liu, Zhen
2016-01-01
We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
Directory of Open Access Journals (Sweden)
Zhen Liu
2017-02-01
Full Text Available We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
High-temperature expansion of the one-loop free energy of a scalar field on a curved background
Kalinichenko, I S
2013-01-01
The high-temperature expansion of the one-loop contribution to the free energy of a scalar field on a stationary gravitational background is derived. The explicit expressions for the divergent and finite parts of the high-temperature expansion in a three-dimensional space without boundaries are obtained. These formulas generalize the known one for the static spacetime. In particular, for a massless conformal scalar field, the leading correction to the Planck law proportional to the temperature squared turns out to be nonzero due to the non-static nature of the metric. The explicit expression for the so-called energy-time anomaly is found. The interrelation between this anomaly and the conformal (trace) anomaly is established.
High-temperature expansion of the one-loop free energy of a scalar field on a curved background
Kalinichenko, I. S.; Kazinski, P. O.
2013-04-01
The complete form of the high-temperature expansion of the one-loop contribution to the free energy of a scalar field on a stationary gravitational background is derived. The explicit expressions for the divergent and finite parts of the high-temperature expansion in a three-dimensional space without boundaries are obtained. These formulas generalize the known one for the stationary spacetime. In particular, we confirm that for a massless conformal scalar field the leading correction to the Planck law proportional to the temperature squared turns out to be nonzero due to the nonstatic nature of the metric. The explicit expression for the so-called energy-time anomaly is found. The interrelation between this anomaly and the conformal (trace) anomaly is established. The natural simplest Lagrangian for the “Killing vector field” is given.
Directory of Open Access Journals (Sweden)
Shinya Kanemura
2015-07-01
Full Text Available We calculate radiative corrections to a full set of coupling constants for the 125 GeV Higgs boson at the one-loop level in two Higgs doublet models with four types of Yukawa interaction under the softly-broken discrete Z2 symmetry. The renormalization calculations are performed in the on-shell scheme, in which the gauge dependence in the mixing parameter which appears in the previous calculation is consistently avoided. We first show the details of our renormalization scheme, and present the complete set of the analytic formulae of the renormalized couplings. We then numerically demonstrate how the inner parameters of the model can be extracted by the future precision measurements of these couplings at the high luminosity LHC and the International Linear Collider.
One-loop Wilson loops and the particle-interface potential in AdS/dCFT
de Leeuw, Marius; Kristjansen, Charlotte; Wilhelm, Matthias
2016-01-01
We initiate the calculation of quantum corrections to Wilson loops in a class of four-dimensional defect conformal field theories with vacuum expectation values (vevs) based on N=4 super Yang-Mills theory. Concretely, we consider an infinite straight Wilson line, obtaining explicit results for the one-loop correction to its expectation value. This allows us to extract the particle-interface potential of the theory. We compare our results to those of a previous calculation in the dual string-theory set-up consisting of a D3-D5 probe-brane system with flux. In a double-scaling limit, we find agreement up to contributions that correspond to a shift in the vev of the scalar fields.
Kanemura, Shinya; Yagyu, Kei
2015-01-01
We calculate radiative corrections to a full set of coupling constants for the 125 GeV Higgs boson at the one-loop level in two Higgs doublet models with four types of Yukawa interaction under the softly-broken discrete $Z_2$ symmetry. The renormalization calculations are performed in the on-shell scheme, in which the gauge dependence in the mixing parameter which appears in the previous calculation is consistently avoided. We first show the details of our renormalizaton scheme, and present the complete set of the analytic formulae of the renormalized couplings. We then numerically demonstrate how the inner parameters of the model can be extracted by the future precision measurements of these couplings at the high luminosity LHC and the International Linear Collider.
Matos, T
2011-01-01
Starting with a scalar field in a thermal bath and using the one loop quantum correction potential, we rewrite the Klein-Gordon equation in its thermodynamical representation and study the behavior of this scalar field due to temperature variations in the equations of motion. We find the generalization of a Gross-Pitaevskii like equation for a relativistic Bose gas with finite temperature, the corresponding thermodynamic and viscosity expressions, and an expression for the postulate of the first law of the thermodynamics for this BECs. We also propose that the equations obtained might help to explain at some level the phase transition of a Bose-Einstein Condensate in terms of quantum field theory in a simple way.
One-Loop Calculations and Detailed Analysis of the Localized Non-Commutative p^{-2} U(1 Gauge Model
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Daniel N. Blaschke
2010-05-01
Full Text Available This paper carries forward a series of articles describing our enterprise to construct a gauge equivalent for the θ-deformed non-commutative p^{-2} model originally introduced by Gurau et al. [Comm. Math. Phys. 287 (2009, 275-290]. It is shown that breaking terms of the form used by Vilar et al. [J. Phys. A: Math. Theor. 43 (2010, 135401, 13 pages] and ourselves [Eur. Phys. J. C: Part. Fields 62 (2009, 433-443] to localize the BRST covariant operator (D^2θ^2D^2^{-1} lead to difficulties concerning renormalization. The reason is that this dimensionless operator is invariant with respect to any symmetry of the model, and can be inserted to arbitrary power. In the present article we discuss explicit one-loop calculations, and analyze the mechanism the mentioned problems originate from.
Liu, Zhen; Gu, Pei-Hong
2017-02-01
We extend some two Higgs doublet models, where the Yukawa couplings for the charged fermion mass generation only involve one Higgs doublet, by two singlet scalars respectively carrying a singly electric charge and a doubly electric charge. The doublet and singlet scalars together can mediate a two-loop diagram to generate a tiny Majorana mass matrix of the standard model neutrinos. Remarkably, the structure of the neutrino mass matrix is fully determined by the symmetric Yukawa couplings of the doubly charged scalar to the right-handed leptons. Meanwhile, a one-loop induced neutrinoless double beta decay can arrive at a testable level even if the electron neutrino has an extremely small Majorana mass. We also study other experimental constraints and implications including some rare processes and Higgs phenomenology.
Reyes, Carlos M
2016-01-01
We study perturbative unitarity in a Lorentz symmetry violating QED model with higher-order derivative operators in the light of the results of Lee and Wick to preserve unitarity in indefinite metric theories. Specifically, we consider the fermionic sector of the Myers-Pospelov model, which includes dimension five operators, coupled to standard photons. We canonically quantize the model and show that its Hamiltonian is stable, emphasizing the exact stage at which the indefinite metric appears and decomposes into a positive-metric sector and negative-metric sector. Finally, we verify the optical theorem at the one-loop level in the annihilation channel of the forward scattering process $e^+(p_2, r) + e^-(p_1,s)$ by applying the Lee-Wick prescription in which the states associated with the negative metric are left out from the asymptotic Hilbert space.
The One-Loop Six-Dimensional Hexagon Integral and its Relation to MHV Amplitudes in N=4 SYM
Energy Technology Data Exchange (ETDEWEB)
Dixon, Lance J.; /CERN /SLAC; Drummond, James M.; /CERN /Annecy, LAPTH; Henn, Johannes M.; /Humboldt U., Berlin
2011-08-19
We provide an analytic formula for the (rescaled) one-loop scalar hexagon integral {tilde {Phi}}{sub 6} with all external legs massless, in terms of classical polylogarithms. We show that this integral is closely connected to two integrals appearing in one- and two-loop amplitudes in planar N = 4 super-Yang-Mills theory, {Omega}{sup (1)} and {Omega}{sup (2)}. The derivative of {Omega}{sup (2)} with respect to one of the conformal invariants yields {tilde {Phi}}{sub 6}, while another first-order differential operator applied to {tilde {Phi}}{sub 6} yields {Omega}{sup (1)}. We also introduce some kinematic variables that rationalize the arguments of the polylogarithms, making it easy to verify the latter differential equation. We also give a further example of a six-dimensional integral relevant for amplitudes in N = 4 super-Yang-Mills.
Variational Calculation of the Effective Action
Sugihara, T
1998-01-01
An indication of spontaneous symmetry breaking is found in the two-dimensional $\\lambda\\phi^4$ model, where an attention is payed to a functional form of an effective action. An effective energy, which is an effective action for a static field, is obtained as a functional of the classical field from the ground state of hamiltonian $H[J]$ interacting with a constant external field. The energy and wavefunction of the ground state are calculated in terms of DLCQ (Discretized Light-Cone Quantization) under antiperiodic boundary condition. A field configuration which is physically meaningful is found as a solution of the quantum mechanical Euler-Lagrange equation in the $J\\to 0$ limit. It is shown that there exists a nontrivial field configuration in the broken phase of $Z_2$ symmetry because of a boundary effect.
The one-loop worldsheet S-matrix for the AdS n × S n × T 10-2 n superstring
Roiban, Radu; Sundin, Per; Tseytlin, Arkady; Wulff, Linus
2014-08-01
We compute the massive-sector worldsheet S-matrix for superstring theories in AdS n × S n × T 10-2 n (with n = 2 , 3 , 5) in the near BMN expansion up to one-loop order in inverse string tension. We show that, after taking into account the wave function renormalization, the one-loop S-matrix is UV finite. In an appropriate regularization scheme the S-matrix is consistent with the underlying symmetries of the superstring theory, i.e. for the n=3 ,5casesitcoincideswiththeoneimpliedbythelight-conegaugesymmetrieswiththe dressing phases determined from the crossing equations. For the n = 2 , 3 cases we observe that the massless modes decouple from the one-loop calculation of massive mode scattering, i.e. the 2 n-dimensional supercoset sigma model and the full 10-dimensional superstring happen to have the same massive one-loop S-matrix.
Guillet, J Ph; Rodgers, M; Zidi, M S
2013-01-01
In this article we provide representations for the one-loop three point functions in 4 and 6 dimensions in the general case with complex masses. The latter are part of the GOLEM library used for the computation of one-loop multileg amplitudes. These representations are one-dimensional integrals designed to be free of instabilites induced by inverse powers of Gram determinants, therefore suitable for stable numerical implementations.
Geometrical effective action and Wilsonian flows
Pawlowski, J M
2003-01-01
A gauge invariant flow equation is derived by applying a Wilsonian momentum cut-off to gauge invariant field variables. The construction makes use of the geometrical effective action for gauge theories in the Vilkovisky-DeWitt framework. The approach leads to modified Nielsen identities that pose non-trivial constraints on consistent truncations. We also evaluate the relation of the present approach to gauge fixed formulations as well as discussing possible applications.
Holographic Heavy-Light Chiral Effective Action
Liu, Yizhuang
2016-01-01
We propose a variant of the $D4$-$D8$ construction to describe the low energy effective theory of heavy-light mesons, interacting with the lowest lying pseudoscalar and vector mesons. The heavy degrees of freedom are identified with the $D8_L$-$D8_H$ string low energy modes, and are approximated near the world volume of $N_f-1$ light $D8_L$ branes, by fundamental vector field valued in $U(N_f-1)$. The effective action follows from the reduction of the bulk D-brane Born-Infeld (DBI) and Chern-Simons (CS) actions, and is shown to exhibit both chiral and heavy-quark symmetry. The action interpolates continuously between the $U(N_f)$ case with massless mesons, and the $U(N_f-1)$ case with heavy-light mesons. The heavy-light meson radial spectrum is Regge-like. The one-pion and two-pion couplings to the heavy-light multiplets are evaluated. The partial widths for the charged decays $G\\rightarrow H+\\pi$ are shown to be comparable to the recently reported full widths for both the charm and bottom mesons.
Effective actions for relativistic fluids from holography
de Boer, Jan; Pinzani-Fokeeva, Natalia
2015-01-01
Motivated by recent progress in developing action formulations of relativistic hydrodynamics, we use holography to derive the low energy dissipationless effective action for strongly coupled conformal fluids. Our analysis is based on the study of novel double Dirichlet problems for the gravitational field, in which the boundary conditions are set on two codimension one timelike hypersurfaces (branes). We provide a geometric interpretation of the Goldstone bosons appearing in such constructions in terms of a family of spatial geodesics extending between the ultraviolet and the infrared brane. Furthermore, we discuss supplementing double Dirichlet problems with information about the near-horizon geometry. We show that upon coupling to a membrane paradigm boundary condition, our approach reproduces correctly the complex dispersion relation for both sound and shear waves. We also demonstrate that upon a Wick rotation, our formulation reproduces the equilibrium partition function formalism, provided the near-horiz...
Neutralino Decays in the Complex MSSM at One-Loop: a Comparison of On-Shell Renormalization Schemes
Bharucha, A; von der Pahlen, F; Schappacher, C
2012-01-01
We evaluate two-body decay modes of neutralinos in the Minimal Supersymmetric Standard Model with complex parameters (cMSSM). Assuming heavy scalar quarks we take into account all two-body decay channels involving charginos, neutralinos, (scalar) leptons, Higgs bosons and Standard Model gauge bosons. The evaluation of the decay widths is based on a full one-loop calculation including hard and soft QED radiation. Of particular phenomenological interest are decays involving the Lightest Supersymmetric Particle (LSP), i.e. the lightest neutralino, or a neutral or charged Higgs boson. For the chargino/neutralino sector we employ two different renormalization schemes, which differ in the treatment of the complex phases. In the numerical analysis we concentrate on the decay of the heaviest neutralino and show the results in the two different schemes. The higher-order corrections of the heaviest neutralino decay widths involving the LSP can easily reach a level of about 10-15%, while the corrections to the decays to...
Exact Third-Order Density Perturbation and One-Loop Power Spectrum in General Dark Energy Models
Lee, Seokcheon; Biern, Sang Gyu
2014-01-01
Under the standard perturbation theory (SPT), we obtain the fully consistent third-order density fluctuation and kernels for the general dark energy models without using the Einstein-de Sitter (EdS) universe assumption for the first time. We also show that even though the temporal and spatial components of the SPT solutions can not be separable, one can find the exact solutions to any order in general dark energy models. With these exact solutions, we obtain the less than \\% error correction of one-loop matter power spectrum compared to that obtained from the EdS assumption for $k = 0.1 {\\rm h\\, Mpc}^{-1}$ mode at $z = 0$ (1, 1.5). Thus, the EdS assumption works very well at this scale. However, if one considers the correction for $P_{13}$, the error is about 6 (9, 11) \\% for the same mode at $z = 0$ (1, 1.5). One absorbs $P_{13}$ into the linear power spectrum in the renormalized perturbation theory (RPT) and thus one should use the exact solution instead of the approximation one. The error on the resummed p...
One-loop omega-potential of quantum fields with ellipsoid constant-energy surface dispersion law
Kazinski, P. O.; Shipulya, M. A.
2011-10-01
Rapidly convergent expansions of a one-loop contribution to the partition function of quantum fields with ellipsoid constant-energy surface dispersion law are derived. The omega-potential is naturally decomposed into three parts: the quasiclassical contribution, the contribution from the branch cut of the dispersion law, and the oscillating part. The low- and high-temperature expansions of the quasiclassical part are obtained. An explicit expression and a relation of the contribution from the cut with the Casimir term and vacuum energy are established. The oscillating part is represented in the form of the Chowla-Selberg expansion of the Epstein zeta function. Various resummations of this expansion are considered. The general procedure developed is then applied to two models: massless particles in a box both at zero and nonzero chemical potential, and electrons in a thin metal film. Rapidly convergent expansions of the partition function and average particle number are obtained for these models. In particular, the oscillations of the chemical potential of conduction electrons in graphene and a thin metal film due to a variation of size of the crystal are described.
Associated production of a quarkonium and a Z boson at one loop in a quark-hadron-duality approach
Lansberg, Jean-Philippe
2016-01-01
In view of the large discrepancy about the associated production of a prompt $J/\\psi$ and a $Z$ boson between the ATLAS data at $\\sqrt{s}=8$ TeV and theoretical predictions for Single Parton Scattering (SPS) contributions, we perform an evaluation of the corresponding cross section at one loop accuracy (Next-to-Leading Order, NLO) in a quark-hadron-duality approach, also known as the Colour-Evaporation Model (CEM). This work is motivated by (i) the extremely disparate predictions based on the existing NRQCD fits conjugated with the absence of a full NLO NRQCD computation and (ii) the fact that we believe that such an evaluation provides a likely upper limit of the SPS cross section. In addition to these theory improvements, we argue that the ATLAS estimation of the Double Parton Scattering (DPS) yield may be underestimated by a factor as large as 3 which then reduces the size of the SPS yield extracted from the ATLAS data. Our NLO SPS evaluation also allows us to set an upper limit on $\\sigma_{\\rm eff}$ drivi...
Package-X 2.0: A Mathematica package for the analytic calculation of one-loop integrals
Patel, Hiren H
2016-01-01
This arXiv post announces the public release of Package-X 2.0, a Mathematica package for the analytic calculation of one-loop integrals. Package-X 2.0 can now generate analytic expressions for arbitrarily high rank dimensionally regulated tensor integrals with up to four distinct propagators, each with arbitrary integer weight, near an arbitrary even number of spacetime dimensions, giving UV divergent, IR divergent, and finite parts at (almost) any real-valued kinematic point. Additionally, it can generate multivariable Taylor series expansions of these integrals around any non-singular kinematic point to arbitrary order. All special functions and abbreviations output by Package-X 2.0 supports Mathematica's arbitrary precision evaluation capabilities to deal with issues of numerical stability. Finally, tensor algebraic routines of Package-X have been polished and extended to support open fermion chains both on and off shell. The documentation (equivalent to over 100 printed pages) is accessed through Mathemat...
Energy Technology Data Exchange (ETDEWEB)
Hagiwara, K.; Kanemura, S. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Klasen, M. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Umeda, Y. [Technische Hochschule Aachen (Germany). Inst. fuer Theoretische Physik E
2002-12-01
We study one-loop effects of charginos and neutralinos on the helicity amplitudes for e{sup +}e{sup -} {yields} W{sup +}W{sup -} in the Minimal Supersymmetric Standard Model. The calculation is tested by using two methods. First, the sum rule for the form factors between e{sup +}e{sup -} {yields} W{sup +}W{sup -} and the process where the external W{sup {+-}} bosons are replaced by the corresponding Goldstone bosons {omega}{sup {+-}} is employed to test the analytic expression and accuracy of the numerical program. Second, the decoupling property in the large mass limit is used to test the overall normalization of the amplitudes. These two tests are most effectively carried out when the amplitudes are expanded in terms of the MS couplings of the Standard Model. The resulting perturbation expansion is valid at collider energies below and around the threshold of the light SUSY particles. We find that the corrections to the cross section of the longitudinally polarized W pair production can be as large as minus 1.4% at the threshold of the light chargino-pair production for large scattering angles. We also study the effects of the CP-violating phase in the chargino and neutralino sector on the helicity amplitudes. We find that the resulting CP-violating asymmetries can be at most 0.1%. (orig.)
Constraining the D3-brane effective action
Basu, Anirban
2008-01-01
We consider higher derivative corrections of the type D^{2k} R^2 in the effective action of the D3-brane with trivial normal bundle. Based on the perturbative disc and annulus amplitudes, and constraints of supersymmetry and duality, we argue that these interactions are protected, at least for small values of k. Their coefficient functions receive only a finite number of perturbative contributions, and non-perturbative contributions from D-instantons. We propose expressions for these modular forms for low values of k.
The influence of action effects in task switching
Directory of Open Access Journals (Sweden)
Sarah eLukas
2013-01-01
Full Text Available According to ideomotor theories, intended effects caused by a certain action are anticipated before action execution. In the present study, we examined the question of whether action effects play a role in cued task switching. In our study, the participants practiced task-response-effect mappings in an acquisition phase, in which action effects occur after a response in a certain task context. In the ensuing transfer phase, the previously practiced mappings were changed in a random, unpredictable task-response-effect mapping. When changed into unpredictable action effects, RT as well as switch costs increased, but this occurred mainly in trials with short preparation time and not with long preparation time. Moreover, switch costs were generally smaller with predictable action effects than with unpredictable action effects. This suggests that anticipated task-specific action effects help to activate the relevant task set before task execution when the task is not yet already prepared based on the cue.
Effective action theory of Andreev level spectroscopy
Galaktionov, Artem V.; Zaikin, Andrei D.
2015-12-01
With the aid of the Keldysh effective action technique we develop a microscopic theory describing Andreev level spectroscopy experiments in nontunnel superconducting contacts. We derive an effective impedance of such contacts which accounts for the presence of Andreev levels in the system. At subgap bias voltages and low temperatures, inelastic Cooper pair tunneling is accompanied by transitions between these levels resulting in a set of sharp current peaks. We evaluate the intensities of such peaks, establish their dependence on the external magnetic flux piercing the structure and estimate the thermal broadening of these peaks. We also specifically address the effect of capacitance renormalization in a nontunnel superconducting contact and its impact on both the positions and heights of the current peaks. At overgap bias voltages, the I -V curve is determined by quasiparticle tunneling and contains current steps related to the presence of discrete Andreev states in our system.
Exact third-order density perturbation and one-loop power spectrum in general dark energy models
Directory of Open Access Journals (Sweden)
Seokcheon Lee
2014-09-01
Full Text Available Under the standard perturbation theory (SPT, we obtain the fully consistent third-order density fluctuation and kernels for the general dark energy models without using the Einstein–de Sitter (EdS universe assumption for the first time. We also show that even though the temporal and spatial components of the SPT solutions cannot be separable, one can find the exact solutions to any order in general dark energy models. With these exact solutions, we obtain the less than % error correction of one-loop matter power spectrum compared to that obtained from the EdS assumption for k=0.1 hMpc−1 mode at z=0(1,1.5. Thus, the EdS assumption works very well at this scale. However, if one considers the correction for P13, the error is about 6 (9, 11% for the same mode at z=0(1,1.5. One absorbs P13 into the linear power spectrum in the renormalized perturbation theory (RPT and thus one should use the exact solution instead of the approximation one. The error on the resummed propagator N of RPT is about 14 (8, 6% at z=0(1,1.5 for k=0.4 hMpc−1. For k=1 hMpc−1, the error correction of the total matter power spectrum is about 3.6 (4.6, 4.5% at z=0(1,1.5. Upcoming observation is required to archive the sub-percent accuracy to provide the strong constraint on the dark energy and this consistent solution is prerequisite for the model comparison.
All Non-Maximally-Helicity-Violating One-Loop Seven-Gluon Amplitudes in N=4 Super-Yang-Mills Theory
Bern, Z; Dixon, L J; Kosower, D A; Bern, Zvi; Duca, Vittorio Del; Dixon, Lance J.; Kosower, David A.
2004-01-01
We compute the non-MHV one-loop seven-gluon amplitudes in N=4 super-Yang-Mills theory, which contain three negative-helicity gluons and four positive-helicity gluons. There are four independent color-ordered amplitudes, (- - - + + + +), (- - + - + + +), (- - + + -+ +) and (- + - + - + +). The MHV amplitudes containing two negative-helicity and five positive-helicity gluons were computed previously, so all independent one-loop seven-gluon helicity amplitudes are now known for this theory. We present partial information about an infinite sequence of next-to-MHV one-loop helicity amplitudes, with three negative-helicity and n-3 positive-helicity gluons, and the color ordering (- - - + + ... + +); we give a new coefficient of one class of integral functions entering this amplitude. We discuss the twistor-space properties of the box-integral-function coefficients in the amplitudes, which are quite simple and suggestive.
The Non-Maximally-Helicity-Violating One-Loop Seven-Gluon Amplitudes in N=4 Super-Yang-Mills Theory
Energy Technology Data Exchange (ETDEWEB)
Bern, Z.
2004-10-22
We compute the non-MHV one-loop seven-gluon amplitudes in N = 4 super-Yang-Mills theory, which contain three negative-helicity gluons and four positive-helicity gluons. There are four independent color-ordered amplitudes, (---++++), (--+-+++), (--++-++) and (-+-+-++). The MHV amplitudes containing two negative-helicity and five positive-helicity gluons were computed previously, so all independent one-loop seven-gluon helicity amplitudes are now known for this theory. We present partial information about an infinite sequence of next-to-MHV one-loop helicity amplitudes, with three negative-helicity and n - 3 positive-helicity gluons, and the color ordering (---+{center_dot}{center_dot}{center_dot}++); we give a new coefficient of one class of integral functions entering this amplitude. We discuss the twistor-space properties of the box-integral-function coefficients in the amplitudes, which are quite simple and suggestive.
Exploring soft constraints on effective actions
Bianchi, Massimo; Huang, Yu-tin; Lee, Chao-Jung; Wen, Congkao
2016-01-01
We study effective actions for simultaneous breaking of space-time and internal symmetries. Novel features arise due to the mixing of Goldstone modes under the broken symmetries which, in contrast to the usual Adler's zero, leads to non-vanishing soft limits. Such scenarios are common for spontaneously broken SCFT's. We explicitly test these soft theorems for $\\mathcal{N}=4$ sYM in the Coulomb branch both perturbatively and non-perturbatively. We explore the soft constraints systematically utilizing recursion relations. In the pure dilaton sector of a general CFT, we show that all amplitudes up to order $s^{n} \\sim \\partial^{2n}$ are completely determined in terms of the $k$-point amplitudes at order $s^k$ with $k \\leq n$. Terms with at most one derivative acting on each dilaton insertion are completely fixed and coincide with those appearing in the conformal DBI, i.e. DBI in AdS. With maximal supersymmetry, the effective actions are further constrained, leading to new non-renormalization theorems. In particu...
Radiative corrections and the Palatini action
Brandt, F. T.; McKeon, D. G. C.
2016-05-01
By using the Faddeev-Popov quantization procedure, we demonstrate that the radiative effects computed using the first-order and second-order Einstein-Hilbert action for general relativity are the same, provided one can discard tadpoles. In addition, we show that the first-order form of this action can be used to obtain a set of Feynman rules that involves just two propagating fields and three three-point vertices; using these rules is considerably simpler than employing the infinite number of vertices that occur in the second-order form. We demonstrate this by computing the one-loop, two-point function.
New lattice action for heavy quarks
Energy Technology Data Exchange (ETDEWEB)
Oktay, Mehmet B.; Kronfeld, Andreas S.
2008-03-01
We extend the Fermilab method for heavy quarks to include interactions of dimension six and seven in the action. There are, in general, many new interactions, but we carry out the calculations needed to match the lattice action to continuum QCD at the tree level, finding six non-zero couplings. Using the heavy-quark theory of cutoff effects, we estimate how large the remaining discretization errors are. We find that our tree-level matching, augmented with one-loop matching of the dimension-five interactions, can bring these errors below 1%, at currently available lattice spacings.
From action intentions to action effects: how does the sense of agency come about?
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Valérian eChambon
2014-05-01
Full Text Available Sense of agency refers to the feeling of controlling an external event through one’s own action. On one influential view, agency depends on how predictable the consequences of one’s action are, getting stronger as the match between predicted and actual effect of an action gets closer. Thus, sense of agency arises when external events that follow our action are consistent with predictions of action effects made by the motor system while we perform or simply intend to perform an action. According to this view, agency is inferred retrospectively, after an action has been performed and its consequences are known. In contrast, little is known about whether and how internal processes involved in the selection of actions may influence subjective sense of control, in advance of the action itself, and irrespective of effect predictability. In this article, we review several classes of behavioural and neuroimaging data suggesting that earlier processes, linked to fluency of action selection, prospectively contribute to sense of agency. These findings have important implications for better understanding human volition and abnormalities of action experience.
Causal binding of actions to their effects.
Buehner, Marc J; Humphreys, Gruffydd R
2009-10-01
According to widely held views in cognitive science harking back to David Hume, causality cannot be perceived directly, but instead is inferred from patterns of sensory experience, and the quality of these inferences is determined by perceivable quantities such as contingency and contiguity. We report results that suggest a reversal of Hume's conjecture: People's sense of time is warped by the experience of causality. In a stimulus-anticipation task, participants' response behavior reflected a shortened experience of time in the case of target stimuli participants themselves had generated, relative to equidistant, equally predictable stimuli they had not caused. These findings suggest that causality in the mind leads to temporal binding of cause and effect, and extend and generalize beyond earlier claims of intentional binding between action and outcome.
Motor imagery during action observation modulates automatic imitation effects in rhythmical actions
Directory of Open Access Journals (Sweden)
Daniel Lloyd Eaves
2014-02-01
Full Text Available We have previously shown that passively observing a task-irrelevant rhythmical action can bias the cycle time of a subsequently executed rhythmical action. Here we use the same paradigm to investigate the impact of different forms of motor imagery (MI during action observation (AO on this automatic imitation (AI effect. Participants saw a picture of the instructed action followed by a rhythmical distractor movie, wherein cycle time was subtly manipulated across trials. They then executed the instructed rhythmical action. When participants imagined performing the instructed action in synchrony with the distractor action (AO + MI, a strong imitation bias was found that was significantly greater than in our previous study. The bias was pronounced equally for compatible and incompatible trials, wherein observed and imagined actions were different in type (e.g., face washing vs. painting or plane of movement, or both. In contrast, no imitation bias was observed when MI conflicted with AO. In Experiment 2, motor execution synchronised with AO produced a stronger imitation bias compared to AO + MI, showing an advantage in synchronisation for overt execution over MI. Furthermore, the bias was stronger when participants synchronised the instructed action with the distractor movie, compared to when they synchronised the distractor action with the distractor movie. Although we still observed a significant bias in the latter condition, this finding indicates a degree of specificity in AI effects for the identity of the synchronised action. Overall, our data show that MI can substantially modulate the effects of AO on subsequent execution, wherein: (1 combined AO + MI can enhance AI effects relative to passive AO; (2 observed and imagined actions can be flexibly coordinated across different action types and planes; and (3 conflicting AO + MI can abolish AI effects. Therefore, combined AO + MI instructions should be considered in motor training and
Inflationary magnetogenesis and non-local actions: The conformal anomaly
El-Menoufi, Basem Kamal
2015-01-01
We discuss the possibility of successful magnetogenesis during inflation by employing the one-loop effective action of massless QED. The action is strictly non-local and results from the long distance fluctuations of massless charged particles present at the inflationary scale. Most importantly, it encodes the conformal anomaly of QED which is crucial to avoid the vacuum preservation in classical electromagnetism. In particular, we find a blue spectrum for the magnetic field with spectral index $n_B \\simeq 2 - \\alpha_{\\text{e}}$ where $\\alpha_{\\text{e}}$ depends on both the number of e-folds during inflation as well as the coefficient of the one-loop beta function. In particular, the sign of the beta function has important bearing on the final result. A low reheating temperature is required for the present day magnetic field to be consistent with the lower bound inferred on the field in the intergalactic medium.
The one-loop worldsheet S-matrix for the AdS(n) x S(n) x T(10-2n) superstring
Roiban, Radu; Tseytlin, Arkady; Wulff, Linus
2014-01-01
We compute the massive-sector worldsheet S-matrix for superstring theories in AdS(n) x S(n) x T(10-2n) (with n=2,3,5) in the near BMN expansion up to one-loop order in inverse string tension. We show that, after taking into account the wave function renormalization, the one-loop S-matrix is UV finite. In an appropriate regularization scheme the S-matrix is consistent with the underlying symmetries of the superstring theory, i.e. for the n=3,5 cases it coincides with the one implied by the light-cone gauge symmetries with the dressing phases determined from the crossing equations. For the n=2,3 cases we observe that the massless modes decouple from the one-loop calculation of massive mode scattering, i.e. the 2n-dimensional supercoset sigma model and the full 10-dimensional superstring happen to have the same massive one-loop S-matrix.
String effective actions, dualities, and generating solutions
Chemissany, Wissam Ali
2008-01-01
This thesis covers in general two separate topics: the string e®ective actions and the geodesic motion of brane solutions. The main theme of the ¯rst topic, i.e., the string e®ective actions, is the construction of the abelian D-brane e®ective action. In the limit of constant ¯eld strengths this act
Universality of Mixed Action Extrapolation Formulae
Chen, Jiunn-Wei; Walker-Loud, Andre
2009-01-01
Mixed action theories with chirally symmetric valence fermions exhibit very desirable features both at the level of the lattice calculations as well as in the construction and implementation of the low energy mixed action effective field theory. In this work we show that when the mixed action effective field theory is projected onto the valence sector, both the Lagrangian and the extrapolation formulae become universal in form through next to leading order, for all variants of discretization methods used for the sea fermions. This implies that for all sea quark methods which are in the same universality class as QCD, the numerical values of the physical coefficients in the various mixed action chiral Lagrangians will be the same up to perturbative lattice spacing dependent corrections. This allows us to construct a prescription to determine the mixed action extrapolation formulae for a large class of hadronic correlation functions computed in partially quenched chiral perturbation theory at the one-loop level...
Shocking action: Facilitative effects of punishing electric shocks on action control.
Eder, Andreas B; Dignath, David; Erle, Thorsten M; Wiemer, Julian
2017-08-01
Four experiments examined motivational effects of response-contingent electric shocks on action initiation. Although the shock was unambiguously aversive for the individual in line with subjective and functional criteria, results showed that the shock-producing action was initiated faster relative to a response producing no shock. However, no facilitation effect was found when strong shocks were delivered, ruling out increased emotional arousal as an explanation. The action was initiated faster even when the response discontinued to generate a shock. Furthermore, a control experiment with affectively neutral vibrotactile stimulations at homologous sites showed an analogous response facilitation effect. Overall, the results contradict the widespread belief that a contingency with a punishing response effect is sufficient for a response suppression. Instead, the results suggest that punishing action effects can facilitate action initiation via anticipatory feedback processes. Implications for theories and applications of punishment are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
The effective action in four-dimensional CDT
Gizbert-Studnicki, Jakub
2015-01-01
We present recent results concerning the measurement and analysis of the effective action in four-dimensional Causal Dynamical Triangulations. The action describes quantum fluctuations of the spatial volume of the CDT universe (or alternatively the scale factor) after integrating out other degrees of freedom. We use the covariance of volume fluctuations to measure and parametrize the effective action inside the de Sitter phase, also called the C phase. We show that the action is consistent with a simple discretization of the minisuperspace action (with a reversed overall sign). We discuss possible subleading corrections and show how to construct a more complicated effective action comprising both integer and half-integer discrete proper time layers. We introduce a new method of the effective action measurement based on the transfer matrix. We show that the results of the new method are fully consistent with the covariance matrix method inside the de Sitter phase. We use the new method to measure the effective...
Action-effect congruence during observational learning leads to faster action sequence learning.
Horvath, Jared C; Gray, Zachary; Schilberg, Lukas; Vidrin, Ilya; Pascual-Leone, Alvaro
2015-01-01
Common coding theory suggests that any action (pressing a piano key) is intimately linked with its resultant sensory effect (an auditory musical tone). We conducted two experiments to explore the effect of varying auditory action-effect patterns during complex action learning. In Experiment 1, participants were assigned to 1 of 4 groups, watched a silent video of a hand playing a sequence on a piano keyboard with no auditory action effect (observation) and were asked to practise and perform the sequence on an identical keyboard with varying action effects (reproduction). During reproduction, Group 1 heard no auditory tones (identical to observed video), Group 2 heard typical scale-ascending piano tones with each key press, Group 3 heard fixed but out-of-sequence piano tones with each key press, and Group 4 heard random piano tones with each key press. In Experiment two, new participants were assigned to 1 of 2 groups and watched an identical video; however, the video in this experiment contained typical, scale-ascending piano sounds. During reproduction, Group 1 heard no auditory tones while Group 2 heard typical, scale-ascending piano tones with each key press (identical to observed video). Our results showed that participants whose action-effect patterns during reproduction matched those in the observed video learned the action sequence faster than participants whose action-effect patterns during reproduction differed from those in the observed video. Additionally, our results suggest that adding an effect during reproduction (when one is absent during observation) is somewhat more detrimental to action sequence learning than removing an effect during reproduction (when one is present during observation).
Effects of social intention on movement kinematics in cooperative actions
Directory of Open Access Journals (Sweden)
Francois eQuesque
2013-10-01
Full Text Available Optimal control models of biological movements are used to account for those internal variables that constrain voluntary goal-directed actions. They however do not take into account external environmental constraints as those associated to social intention. We investigated here the effects of the social context on kinematic characteristics of sequential actions consisting in placing an object on an initial pad (preparatory action before reaching and grasping as fast as possible the object to move it to another location (main action. Reach-to-grasp actions were performed either in an isolated condition or in the presence of a partner (audience effect, located in the near or far space (effect of shared reachable space, and who could intervene on the object in a systematic fashion (effect of social intention effect or not (effect of social uncertainty. Results showed an absence of audience effect but nevertheless an influence of the social context both on the main and the preparatory actions. In particular, a localized effect of shared reachable space was observed on the main action, which was smoother when performed within the reachable space of the partner. Furthermore, a global effect of social uncertainty was observed on both actions with faster and jerkier movements. Finally, social intention affected the preparatory action with higher wrist displacements and slower movements when the object was placed for the partner rather than placed for self-use. Overall, these results demonstrate specific effects of action space, social uncertainty and social intention on the planning of reach-to-grasp actions, in particular on the preparatory action, which was performed with no specific execution constraint. These findings underline the importance of considering the social context in optimal models of action control for human-robot interactions, in particular when focusing on the implementation of motor parameters required to afford intuitive
Georgiou, George; Grossardt, Andre; Plefka, Jan
2012-01-01
We report on a systematic perturbative study of three-point functions in planar SU(N) N=4 super Yang-Mills theory at the one-loop level involving scalar field operators up to length five. For this we have computed a sample of 40 structure constants involving primary operators of up to and including length five which are built entirely from scalar fields. A combinatorial dressing technique has been developed to promote tree-level correlators to one-loop level. In addition we have resolved the mixing up to the order (g_YM)^2 level of the operators involved, which amounts to mixings with bi-fermions, with bi-derivative insertions as well as self-mixing contributions in the scalar sector. This work supersedes a preprint by two of the authors from 2010 which had neglected the mixing contributions.
Boussarie, R; Szymanowski, L; Wallon, S
2016-01-01
We present the calculation of the impact factor for the $\\gamma^{(*)}\\to q\\bar{q}$ transition with one loop accuracy in arbitrary kinematics. The calculation was done within Balitsky's high energy operator expansion. Together with our previous result for the $\\gamma^{(*)}\\to q\\bar{q} g$ Born impact factor it allows one to derive cross-sections for 2- (one loop) and 3-jet (Born) difractive electroproduction. We write such cross sections for the 2 and 3 jet exclusive diffractive electroproduction off a proton in terms of hadronic matrix elements of Wilson lines. For the 2-jet cross section we demonstrate the cancellation of IR, collinear and rapidity singularities. Our result can be directly exploited to describe the recently analyzed data on exclusive dijet production at HERA and used for the study of jet photoproduction in ultraperipheral proton or nuclear scattering.
One-loop supergravity on $\\mathrm{AdS}_4\\times S^7/\\mathbb{Z}_k$ and comparison with ABJM theory
Liu, James T
2016-01-01
The large-$N$ limit of ABJM theory is holographically dual to M-theory on AdS$_4\\times S^7/\\mathbb{Z}_k$. The 3-sphere partition function has been obtained via localization, and its leading behavior $F_{\\text{ABJM}}^{(0)}\\sim k^{1/2}N^{3/2}$ is exactly reproduced in the dual theory by tree-level supergravity. We extend this comparison to the sub-leading $\\mathcal O(N^0)$ order by computing the one-loop supergravity free energy as a function of $k$ and comparing it with the ABJM result. Curiously, we find that the expressions do not match, with $F_{\\text{SUGRA}}^{(1)}\\sim k^6$, while $F_{\\text{ABJM}}^{(1)}\\sim k^2$. This suggests that the low-energy approximation $Z_{\\text{M-theory}}=Z_{\\text{SUGRA}}$ breaks down at one-loop order.
Foundation ActionScript 30 Image Effects
Yard, Todd
2009-01-01
Flash has always been a tool for delivering compelling and unique experiences through dynamic visual presentation. The Flash platform has grown to include application development in Flex, video streaming with the Flash Media Server, and desktop delivery through AIR, but all of that content still comes down to pixels on the screen, and all of those pixels can be manipulated through the power of the ActionScript language. In this book, you will find in-depth coverage of the graphics capabilities of ActionScript 3.0: the enhanced drawing API in Flash Player 10 that allows you to draw vector shape
Action-specific effects in perception and their potential applications
Witt, Jessica K.; Linkenauger, Sally; Wickens, Chris
2016-01-01
Spatial perception is biased by action. Hills appear steeper and distances appear farther to individuals who would have to exert more effort to transverse the space. Objects appear closer, smaller, and faster when they are easier to obtain. Athletes who are playing better than others see their targets as bigger. These phenomena are collectively known as action-specific effects on perception. In this target article, we review evidence for action-specific effects, including evidence that they r...
Effective Action and Schwinger Pair Production in Strong QED
Kim, Sang Pyo
2009-01-01
Some field theoretical aspects, such as the effective action and Schwinger pair production, are critically reviewed in strong QED. The difference of the boundary conditions on the solutions of the field equation is discussed to result in the effective action both in the Coulomb and time-dependent gauge. Finally, the apparent spin-statistics inversion is also discussed, where the WKB action for bosons (fermions) works well for fermion (boson) pair-production rate.
Effective action for supersymmetric chiral anomaly
Energy Technology Data Exchange (ETDEWEB)
Krivoshchekov, V.K.; Chekhov, L.O.
1987-05-01
It is shown that consistency conditions of the type of the Wess-Zumino conditions are necessary and sufficient conditions for local integrability of the supersymmetric chiral anomaly. It follows from the requirement of global integrability that the coefficient of the anomalous action is discrete. Explicit expressions are obtained for consistent anomalies and the corresponding functionals, which depend on superfields of various types.
Effective action and semiclassical limit of spin foam models
Mikovic, A
2011-01-01
We define an effective action for spin foam models of quantum gravity by adapting the background field method from quantum field theory. We show that the Regge action is the leading term in the semi-classical expansion of the spin foam effective action if the vertex amplitude has the large-spin asymptotics which is proportional to an exponential function of the vertex Regge action. In the case of the known three-dimensional and four-dimensional spin foam models this amounts to modifying the vertex amplitude such that the exponential asymptotics is obtained. In particular, we show that the ELPR/FK model vertex amplitude can be modified such that the new model is finite and has the Einstein-Hilbert action as its classical limit. We also calculate the first-order and some of the second-order quantum corrections in the semi-classical expansion of the effective action.
Action-effect learning in early childhood: does language matter?
Karbach, Julia; Kray, Jutta; Hommel, Bernhard
2011-07-01
Previous work showed that language has an important function for the development of action control. This study examined the role of verbal processes for action-effect learning in 4-year-old children. Participants performed an acquisition phase including a two-choice key-pressing task in which each key press (action) was followed by a particular sound (effect). Children were instructed to either (1) label their actions along with the corresponding effects, (2) verbalize task-irrelevant words, (3) or perform without verbalization. In a subsequent test phase, they responded to the same sound effects either under consistent or under inconsistent sound-key mappings. Evidence for action-effect learning was obtained only if action and effects were labeled or if no verbalization was performed, but not if children verbalized task-irrelevant labels. Importantly, action-effect learning was most pronounced when children verbalized the actions and the corresponding effects, suggesting that task-relevant verbal labeling supports the integration of event representations.
Kaluza-Klein monopole and 5-brane effective actions
Eyras, E; Lozano, Y
2000-01-01
We review the construction of the Kaluza-Klein monopole of the Type IIA theory in the most general case of a massive background, as well as its relation via T-duality with the Type IIB NS-5-brane. This last effective action is shown to be related by S-duality to the D5-brane effective action. [GRAPH
Duality symmetries and the type II string effective action
Bergshoeff, E.
1996-01-01
We discuss the duality symmetries of Type II string effective actions in nine, ten and eleven dimensions. As a by-product we give a covariant action underlying the ten-dimensional Type IIB supergravity theory. We apply duality symmetries to construct dyonic Type II string solutions in six dimensions
Effective action for EPRL/FK spin foam models
Mikovic, Aleksandar
2011-01-01
We show that a natural modification of the EPRL/FK vertex amplitude gives a finite spin foam model whose effective action gives the Einstein-Hilbert action in the limit of large spins and arbitrarily fine spacetime triangulations. The first-order quantum corrections can be easily computed and we show how to calculate the higher-order corrections.
Effective action for hard thermal loops in gravitational fields
Directory of Open Access Journals (Sweden)
R.R. Francisco
2016-05-01
Full Text Available We examine, through a Boltzmann equation approach, the generating action of hard thermal loops in the background of gravitational fields. Using the gauge and Weyl invariance of the theory at high temperature, we derive an explicit closed-form expression for the effective action.
Supergravity one-loop corrections on AdS7 and AdS3, higher spins and AdS/CFT
Directory of Open Access Journals (Sweden)
Matteo Beccaria
2015-03-01
Full Text Available As was shown earlier, the one-loop correction in 10d supergravity on AdS5×S5 corresponds to the contributions to the vacuum energy and 4d boundary conformal anomaly which are minus the values for one N=4 Maxwell supermultiplet, thus reproducing the subleading term in the N2−1 coefficient in the dual SU(N SYM theory. We perform similar one-loop computations in 11d supergravity on AdS7×S4 and 10d supergravity on AdS3×S3×T4. In the AdS7 case we find that the corrections to the 6d conformal anomaly a-coefficient and the vacuum energy are again minus the ones for one (2,0 tensor multiplet, suggesting that the total a-anomaly coefficient for the dual (2,0 theory is 4N3−9/4N−7/4 and thus vanishes for N=1. In the AdS3 case the one-loop correction to the vacuum energy or 2d central charge turns out to be equal to that of one free (4,4 scalar multiplet, i.e. is c=+6. This reproduces the subleading term in the central charge c=6(Q1Q5+1 of the dual 2d CFT describing decoupling limit of D5–D1 system. We also present the expressions for the 6d a-anomaly coefficient and vacuum energy contributions of general-symmetry higher spin field in AdS7 and consider their application to tests of vectorial AdS/CFT with the boundary conformal 6d theory represented by free scalars, spinors or rank-2 antisymmetric tensors.
Techniques for calculations with nPI effective actions
Directory of Open Access Journals (Sweden)
Carrington M.E.
2015-01-01
Full Text Available We consider a symmetric scalar theory with quartic coupling in 2- and 3- dimensions and compare the self-consistent 4-point vertex obtained from the 4PI effective action with the Bethe-Salpeter 4-vertex from 2PI effective action. We show that when the coupling is large the contributions from the higher order effective action are large. We also show that one can solve the 2PI equations of motion in 4-dimensions, without introducing counter-terms, using a renormalization group method. This method provides a promising starting point to study the renormalization of higher order nPI theories.
Effective action of 6D F-Theory with U(1) factors: Rational sections make Chern-Simons terms jump
Grimm, Thomas W; Keitel, Jan
2013-01-01
We derive the six-dimensional (1,0) effective action arising from F-theory on an elliptically fibered Calabi-Yau threefold with multiple sections. The considered theories admit both non-Abelian and Abelian gauge symmetries. Our derivation employs the M-theory to F-theory duality in five-dimensions after circle reduction. Five-dimensional gauge and gravitational Chern-Simons terms are shown to arise at one-loop by integrating out massive Coulomb branch and Kaluza-Klein modes. In the presence of a non-holomorphic zero section, we find an improved systematic for performing the F-theory limit by using the concept of the extended relative Mori cone. In this situation Kaluza-Klein modes can become lighter than Coulomb branch modes and a jump in the Chern-Simons levels occurs. By determining Chern-Simons terms for various threefold examples we are able to compute the complete six-dimensional charged matter spectrum and show consistency with six-dimensional anomalies.
Effective supergravity actions for flop transitions
Energy Technology Data Exchange (ETDEWEB)
Jarv, Laur; Mohaupt, Thomas; Saueressig, Frank E-mail: F.Saueressig@tpi.uni-jena.de
2003-12-01
We construct a family of five-dimensional gauged supergravity actions which describe flop transitions of M-theory compactified on Calabi-Yau three folds. While the vector multiplet sector can be treated exactly, we use the Wolf spaces X(1+N) = U(1+N,2)/(U(1+N) x U(2)) to model the universal hyper multiplet together with N charged hyper multiplets corresponding to winding states of the M2-brane. The metric, the Killing vectors and the moment maps of these spaces are obtained explicitly by using the superconformal quotient construction of quaternion-Kaehler manifolds. The inclusion of the extra hyper multiplets gives rise to a non-trivial scalar potential which is uniquely fixed by M-theory physics. (author)
Energy Technology Data Exchange (ETDEWEB)
Kniehl, B.A.; Merebashvili, Z. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Koerner, J.G. [Mainz Univ. (Germany). Inst. fuer Physik; Rogal, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2008-09-15
We calculate the next-to-next-to-leading order O({alpha}{sup 4}{sub s}) one-loop squared corrections to the production of heavy quark pairs in the gluon-gluon fusion process. Together with the previously derived results on the q anti q production channel the results of this paper complete the calculation of the oneloop squared contributions of the next-to-next-to-leading order O({alpha}{sup 4}{sub s}) radiative QCD corrections to the hadroproduction of heavy flavours. Our results, with the full mass dependence retained, are presented in a closed and very compact form, in dimensional regularization. (orig.)
Hagiwara, K; Umeda, Y
2001-01-01
One-loop contributions of super-partner particles to W-pair production at e/sup +/e/sup -/ collision are discussed in the MSSM. To obtain trustworthy results we test our calculation using three methods: (1) sum rules among form factors which result from the BRS invariance, (2) the decoupling theorem, (3) the high-energy stability. We examine the corrections taking into account constraints from the direct search experiments and the precision data. The results for the sfermion contributions are presented.
Energy Technology Data Exchange (ETDEWEB)
Hagiwara, Kaoru [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Kanemura, Shinya [Institut fuer Theoretishce Physik der Universitaet Karlsruhe, Karlsruhe (Germany); Umeda, Yoshiaki [II Institut fuer Theoretishce Physik der Universitaet Hamburg, Hamburg (Germany)
2001-07-01
One-loop contributions of super-partner particles to W-pair production at e{sup +}e{sup -} collision are discussed in the MSSM. To obtain trustworthy results we test our calculation using three methods: (1) sum rules among form factors which result from the BRS invariance, (2) the decoupling theorem, (3) the high-energy stability. We examine the corrections taking into account constraints from the direct search experiments and the precision data. The results for the sfermion contributions are presented. (author)
On the influence of reward on action-effect binding
Directory of Open Access Journals (Sweden)
Paul Simon Muhle-Karbe
2012-11-01
Full Text Available Ideomotor theory states that the formation of anticipatory representations about the perceptual consequences of an action (i.e. action-effect (A-E binding provides the functional basis of voluntary action control. A host of studies has demonstrated that A-E binding occurs fast and effortlessly, yet only little is known about cognitive and affective factors that influence this learning process. In the present study, we sought to test whether the motivational value of an action modulates the acquisition of A-E associations. To this end, we associated specific actions with monetary incentives during the acquisition of novel A-E mappings. In a subsequent test phase, the degree of binding was assessed by presenting the former effect stimuli as task-irrelevant response primes in a forced-choice response task in the absence of any reward. Binding, as indexed by response priming through the former action effects, was only found for reward-related A-E mappings. Moreover, the degree to which reward associations modulated the binding strength was predicted by individuals’ trait sensitivity to reward. These observations indicate that the association of actions and their immediate outcomes depends on the motivational value of the action during learning, as well as on the motivational disposition of the individual. On a larger scale, these findings also highlight the link between ideomotor theories and reinforcement-learning theories, providing an interesting perspective for future research on anticipatory regulation of behavior.
The internal anticipation of sensory action effects: when action induces FFA and PPA activity
Directory of Open Access Journals (Sweden)
Simone Kühn
2010-06-01
Full Text Available Voluntary action – in particular the ability to produce desired effects in the environment – is fundamental to human existence. According to ideomotor theory we can achieve goals in the environment by means of anticipating their outcomes. We aimed at providing neurophysiological evidence for the assumption that performing actions calls for the activation of brain areas associated with the sensory effects usually evoked by the actions. We conducted an fMRI study in which right and left button presses lead to the presentation of face and house pictures. We compared a baseline phase with the same phase after participants experienced the association between button presses and pictures. We found an increase in the parahippocampal place area (PPA for the response that has been associated with house pictures and fusiform face area (FFA for the response that has been coupled with face pictures. This observation constitutes support for ideomotor theory.
World-volume Effective Actions of Exotic Five-branes
Kimura, Tetsuji; Yata, Masaya
2014-01-01
We construct world-volume effective actions of exotic $5^2_2$-branes in type IIA and IIB string theories. The effective actions are given in fully space-time covariant forms with two Killing vectors associated with background isometries. The effective theories are governed by the six-dimensional $\\mathcal{N}=(2,0)$ tensor multiplet and $\\mathcal{N}=(1,1)$ vector multiplet, respectively. Performing the S-duality transformation to the $5^2_2$-brane effective action in type IIB string theory, we also work out the world-volume action of the $5^2_3$-brane. We discuss some additional issues relevant to the exotic five-branes in type I and heterotic string theories.
QCD Effective action at high temperature and small chemical potential
Villavicencio, C
2007-01-01
We present a construction of an effective Yang-Mills action for QCD, from the expansion of the fermionic determinant in terms of powers of the chemical potential at high temperature, for the case of massless quarks. We analyze this expansion in the perturbative region and find that it gives extra spurious information. We propose for the non-perturbative sector a simplified effective action which, in principle, contains only the relevant information.
Energy Technology Data Exchange (ETDEWEB)
Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Universidad Autonoma de Madrid, Instituto de Fisica Teorica (UAM/CSIC), Madrid (Spain); Schappacher, C. [Karlsruhe Institute of Technology, Institut fuer Theoretische Physik, Karlsruhe (Germany)
2016-04-15
For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector precise knowledge of their production properties is mandatory. We evaluate the cross sections for the neutral Higgs boson production at e{sup +}e{sup -} colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanism e{sup +}e{sup -} → h{sub i}Z, h{sub i}γ, h{sub i}h{sub j} (i, j = 1, 2, 3), including soft and hard QED radiation. The dependence of the Higgs boson production cross sections on the relevant cMSSM parameters is analyzed numerically. We find sizable contributions to many cross sections. They are, depending on the production channel, roughly of 10.20 % of the tree-level results, but can go up to 50 % or higher. The full one-loop contributions are important for a future linear e{sup +}e{sup -} collider such as the ILC or CLIC. There are plans to implement the evaluation of the Higgs boson production cross sections into the code FeynHiggs. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Heinemeyer, S. [Campus of International Excellence UAM+CSIC, Madrid (Spain); Universidad Autonoma de Madrid, Instituto de Fisica Teorica (UAM/CSIC), Madrid (Spain); Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Schappacher, C. [Karlsruhe Institute of Technology, Institut fuer Theoretische Physik, Karlsruhe (Germany)
2016-10-15
For the search for additional Higgs bosons in the Minimal Supersymmetric Standard Model (MSSM) as well as for future precision analyses in the Higgs sector precise knowledge of their production properties is mandatory. We evaluate the cross sections for the charged Higgs boson production at e{sup +}e{sup -} colliders in the MSSM with complex parameters (cMSSM). The evaluation is based on a full one-loop calculation of the production mechanism e{sup +}e{sup -} → H{sup +}H{sup -} and e{sup +}e{sup -} → H{sup ±}W{sup -+}, including soft and hard QED radiation. The dependence of the Higgs boson production cross sections on the relevant cMSSM parameters is analyzed numerically. We find sizable contributions to many cross sections. They are, depending on the production channel, roughly of 5-10 % of the tree-level results, but can go up to 20 % or higher. The full one-loop contributions are important for a future linear e{sup +}e{sup -} collider such as the ILC or CLIC. (orig.)
Urban Heat Island Effect Actions - Neighborhood Data
Louisville Metro Government — The urban heat island effect — defined as the difference in temperature between the core of Louisville and its suburbs — contributes to heat-related illnesses and...
Courses of action for effects based operations using evolutionary algorithms
Haider, Sajjad; Levis, Alexander H.
2006-05-01
This paper presents an Evolutionary Algorithms (EAs) based approach to identify effective courses of action (COAs) in Effects Based Operations. The approach uses Timed Influence Nets (TINs) as the underlying mathematical model to capture a dynamic uncertain situation. TINs provide a concise graph-theoretic probabilistic approach to specify the cause and effect relationships that exist among the variables of interest (actions, desired effects, and other uncertain events) in a problem domain. The purpose of building these TIN models is to identify and analyze several alternative courses of action. The current practice is to use trial and error based techniques which are not only labor intensive but also produce sub-optimal results and are not capable of modeling constraints among actionable events. The EA based approach presented in this paper is aimed to overcome these limitations. The approach generates multiple COAs that are close enough in terms of achieving the desired effect. The purpose of generating multiple COAs is to give several alternatives to a decision maker. Moreover, the alternate COAs could be generalized based on the relationships that exist among the actions and their execution timings. The approach also allows a system analyst to capture certain types of constraints among actionable events.
Renormalization and effective actions for general relativity
Energy Technology Data Exchange (ETDEWEB)
Neugebohrn, F.
2007-05-15
Quantum gravity is analyzed from the viewpoint of the renormalization group. The analysis is based on methods introduced by J. Polchinski concerning the perturbative renormalization with flow equations. In the first part of this work, the program of renormalization with flow equations is reviewed and then extended to effective field theories that have a finite UV cutoff. This is done for a scalar field theory by imposing additional renormalization conditions for some of the nonrenormalizable couplings. It turns out that one so obtains a statement on the predictivity of the effective theory at scales far below the UV cutoff. In particular, nonrenormalizable theories can be treated without problems in the proposed framework. In the second part, the standard covariant BRS quantization program for Euclidean Einstein gravity is applied. A momentum cutoff regularization is imposed and the resulting violation of the Slavnov-Taylor identities is discussed. Deriving Polchinski's renormalization group equation for Euclidean quantum gravity, the predictivity of effective quantum gravity at scales far below the Planck scale is investigated with flow equations. A fine-tuning procedure for restoring the violated Slavnov-Taylor identities is proposed and it is argued that in the effective quantum gravity context, the restoration will only be accomplished with finite accuracy. Finally, the no-cutoff limit of Euclidean quantum gravity is analyzed from the viewpoint of the Polchinski method. It is speculated whether a limit with nonvanishing gravitational constant might exist where the latter would ultimatively be determined by the cosmological constant and the masses of the elementary particles. (orig.)
Perception, action, and Roelofs effect: a mere illusion of dissociation.
Directory of Open Access Journals (Sweden)
Paul Dassonville
2004-11-01
Full Text Available A prominent and influential hypothesis of vision suggests the existence of two separate visual systems within the brain, one creating our perception of the world and another guiding our actions within it. The induced Roelofs effect has been described as providing strong evidence for this perception/action dissociation: When a small visual target is surrounded by a large frame positioned so that the frame's center is offset from the observer's midline, the perceived location of the target is shifted in the direction opposite the frame's offset. In spite of this perceptual mislocalization, however, the observer can accurately guide movements to the target location. Thus, perception is prone to the illusion while actions seem immune. Here we demonstrate that the Roelofs illusion is caused by a frame-induced transient distortion of the observer's apparent midline. We further demonstrate that actions guided to targets within this same distorted egocentric reference frame are fully expected to be accurate, since the errors of target localization will exactly cancel the errors of motor guidance. These findings provide a mechanistic explanation for the various perceptual and motor effects of the induced Roelofs illusion without requiring the existence of separate neural systems for perception and action. Given this, the behavioral dissociation that accompanies the Roelofs effect cannot be considered evidence of a dissociation of perception and action. This indicates a general need to re-evaluate the broad class of evidence purported to support this hypothesized dissociation.
Boldine action against the stannous chloride effect.
Reiniger, I W; Ribeiro da Silva, C; Felzenszwalb, I; de Mattos, J C; de Oliveira, J F; da Silva Dantas, F J; Bezerra, R J; Caldeira-de-Araújo, A; Bernardo-Filho, M
1999-12-15
Peumus boldus extract has been used in popular medicine in the treatment of biliar litiase, hepatic insufficiency and liver congestion. Its effects are associated to the substance boldine that is present in its extract. In the present work, we evaluated the influence of boldine both in: (i) the structural conformation of a plasmid pUC 9.1 through gel electrophoresis analysis; and in (ii) the survival of the strain of Escherichia coli AB1157 submitted to reactive oxygen species (ROS), generated by a Fenton like reaction, induced by stannous chloride. Our results show a reduction of the lethal effect induced by stannous chloride on the survival of the E. coli culture in the presence of boldine. The supercoiled form of the plasmid is not modified by stannous chloride in the presence of boldine. We suggest that the protection induced by boldine could be explained by its anti-oxidant mechanism. In this way, the boldine could be reacting with stannous ions, protecting them against the oxidation and, consequently, avoiding the generation of ROS.
Non-dissipative hydrodynamics: effective actions versus entropy current
Bhattacharya, Jyotirmoy; Bhattacharyya, Sayantani; Rangamani, Mukund
2013-02-01
While conventional hydrodynamics incorporating dissipative effects is hard to derive from an action principle, it is nevertheless possible to construct classical actions when the dissipative terms are switched off. In this note we undertake a systematic exploration of such constructions from an effective field theory approach and argue for the existence of non-trivial second order non-dissipative hydrodynamics involving pure energy-momentum transport. We find these fluids to be characterized by five second-order transport coefficients based on the effective action (a three parameter family is Weyl invariant). On the other hand since all flows of such fluids are non-dissipative, they entail zero entropy production; one can therefore understand them using the entropy current formalism which has provided much insight into hydrodynamic transport. An analysis of the most general stress tensor with zero entropy production however turns out to give a seven parameter family of non-dissipative hydrodynamics (a four parameter sub-family being Weyl invariant). The non-dissipative fluids derived from the effective action approach are a special case of the fluid dynamics constrained by conservation of the entropy current. We speculate on the reasons for the mismatch and potential limitations of the effective action approach.
Effective Actions of Matrix Models on Homogeneous Spaces
Imai, T; Takayama, Y; Tomino, D
2002-01-01
We evaluate the effective actions of supersymmetric matrix models on fuzzy S^2times S^2 up to the two loop level. Remarkably it turns out to be a consistent solution of IIB matrix model. Based on the power counting and SUSY cancellation arguments, we can identify the 't Hooft coupling and large N scaling behavior of the effective actions to all orders. In the large N limit, the quantum corrections survive except in 2 dimensional limits. They are O(N) and O(N^{4over 3}) for 4 and 6 dimensional spaces respectively. We argue that quantum effects single out 4 dimensionality of space-time.
Truncation Effects in Monte Carlo Renormalization Group Improved Lattice Actions
Takaishi, T; Forcrand, Ph. de
1998-01-01
We study truncation effects in the SU(3) gauge actions obtained by the Monte Carlo renormalization group method. By measuring the heavy quark potential we find that the truncation effects in the actions coarsen the lattice by 40-50 % from the original blocked lattice. On the other hand, we find that rotational symmetry of the heavy quark potentials is well recovered on such coarse lattices, which may indicate that rotational symmetry breaking terms are easily cancelled out by adding a short distance operator. We also discuss the possibility of reducing truncation effects.
Early markers of ongoing action-effect learning.
Ruge, Hannes; Krebs, Ruth M; Wolfensteller, Uta
2012-01-01
Acquiring knowledge about the relationship between stimulus conditions, one's own actions, and the resulting consequences or effects, is one prerequisite for intentional action. Previous studies have shown that such contextualized associations between actions and their effects (S-R-E associations) can be picked up very quickly. The present study examined how such weakly practiced associations might affect overt behavior during the process of initial learning and during subsequent retrieval, and how these two measures are inter-related. We examined incidental (S-)R-E learning in the context of trial-and-error S-R learning and in the context of instruction-based S-R learning. Furthermore, as a control condition, common outcome (CO) learning blocks were included in which all responses produced one common sound effect, hence precluding differential (S-)R-E learning. Post-learning retrieval of R-E associations was tested by re-using previously produced sound effects as novel imperative stimuli combined with actions that were either compatible or incompatible with the previously encountered R-E mapping. The central result was that the size of the compatibility effect could be predicted by the size of relative response slowing during ongoing learning in the preceding acquisition phase, both in trial-and-error learning and in instruction-based learning. Importantly, this correlation was absent for the CO control condition, precluding accounts based on unspecific factors. Instead, the results suggest that differential outcomes are "actively" integrated into action planning and that this takes additional planning time. We speculate that this might be especially true for weakly practiced (S-)R-E associations before an initial goal-directed action mode transitions into a more stimulus-based action mode.
Early markers of ongoing action-effect learning
Directory of Open Access Journals (Sweden)
Hannes eRuge
2012-11-01
Full Text Available Acquiring knowledge about the relationship between stimulus conditions, one’s own actions, and the resulting consequences or effects, is one prerequisite for intentional action. Previous studies have shown that such contextualized associations between actions and their effects (S-R-E associations can be picked up very quickly. The present study examined how such weakly practiced associations might affect overt behavior during the process of initial learning and during subsequent retrieval, and how these two measures are inter-related. We examined incidental (S-R-E learning in the context of trial-and-error S-R learning and in the context of instruction-based S-R learning. Furthermore, as a control condition, common outcome (CO learning blocks were included in which all responses produced one common sound effect, hence precluding differential (S-R-E learning. Post-learning retrieval of R-E associations was tested by re-using previously produced sound effects as novel imperative stimuli combined with actions that were either compatible or incompatible with the previously encountered R-E mapping. The central result was that the size of the compatibility effect could be predicted by the size of relative response slowing during ongoing learning in the preceding acquisition phase, both in trial-and-error learning and in instruction-based learning. Importantly, this correlation was absent for the common outcome control condition, precluding accounts based on unspecific factors. Instead, the results suggest that differential outcomes are ‘actively’ integrated into action planning and that this takes additional planning time. We speculate that this might be especially true for weakly practiced (S-R-E associations before an initial goal-directed action mode transitions into a more stimulus-based action mode.
The Geometric Construction of WZW Effective Action in Noncommutative Manifold
Institute of Scientific and Technical Information of China (English)
HOU BoYu; WANG YongQiang; YANG ZhanYing; YUE RuiHong
2002-01-01
By constructing close-one-cochain density in the gauge group space we get the Wess Zumino Witten(WZW) effective Lagrangian on high-dimensional noncommutative space. Especially consistent anomalies derived fromthis WZW effective action in noncommutative four-dimensional space coincide with those obtained by L. Bonora etc.(hep-th /0002210).
The Geometric Construction of WZW Effective Action in Noncommutative Manifold
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
By constructing close-one-cochain density Ω12n in the gauge group space we get the Wess-Zumino-Witten (WZW) effective Lagrangian on high-dimensional noncommutative space.Especially consistent anomalies derived from this WZW effective action in noncommutative four-dimensional space coincide with those obtained by L.Bonora etc.(het-th/0002210).
Power effects on cognitive control: Turning conflict into action.
Schmid, Petra C; Kleiman, Tali; Amodio, David M
2015-06-01
Power is known to promote effective goal pursuit, especially when it requires one to overcome distractions or bias. We proposed that this effect involves the ability to engage and implement cognitive control. In Study 1, we demonstrated that power enhances behavioral performance on a response conflict task and that it does so by enhancing controlled processing rather than by reducing automatic processing. In Study 2, we used an event-related potential index of anterior cingulate activity to test whether power effects on control were due to enhanced conflict sensitivity or action implementation. Power did not significantly affect neural sensitivity to conflict; rather, high power was associated with a stronger link between conflict processing and intended action, relative to low power. These findings suggest a new perspective on how social factors can affect controlled processing and offer new evidence regarding the transition between conflict detection and the implementation of action control.
Non-dissipative hydrodynamics: Effective actions versus entropy current
Bhattacharya, Jyotirmoy; Rangamani, Mukund
2012-01-01
While conventional hydrodynamics incorporating dissipative effects is hard to derive from an action principle, it is nevertheless possible to construct classical actions when the dissipative terms are switched off. In this note we undertake a systematic exploration of such constructions from an effective field theory approach and argue for the existence of non-trivial second order non-dissipative hydrodynamics involving pure energy-momentum transport. We find these fluids to be characterized by five second-order transport coefficients based on the effective action (a three parameter family is Weyl invariant). On the other hand since all flows of such fluids are non-dissipative, they entail zero entropy production; one can therefore understand them using the entropy current formalism which has provided much insight into hydrodynamic transport. An analysis of the most general stress tensor with zero entropy production however turns out to give a seven parameter family of non-dissipative hydrodynamics (a four pa...
Vacuum States in 2D Tachyon Effective Action
Kluson, J
2004-01-01
In this paper we will study the ground states of the toy model of 2D closed string tachyon effective action. We will firstly construct the classical solutions of the tachyon effective action that do not induce backreaction on metric and dilaton. Then we will study the quantum mechanics of the zero mode of the tachyon field. We will find family of vacuum states labelled with single parameter. We will also perform the quantum mechanical analysis of the tachyon effective action when we take into account dynamics of nonzero modes. We will calculate the vacuum expectation values of components of the stress energy tensor and dilaton source and we will argue that there is not any backreaction on metric and dilaton.
2PI effective action and gauge invariance problems
Carrington, M. E.; Kunstatter, G.; Zaraket, H.
2003-01-01
The problem of maintaining gauge invariance when truncating the two particle irreducible (2PI) effective action has been studied recently by several authors. Here we give a simple and very general derivation of the gauge dependence identities for the off-shell 2PI effective action. We consider the case where the gauge is fixed by an arbitrary function of the quantum gauge field, subject only to the restriction that the Faddeev-Popov matrix is invertable. We also study the background field gau...
Duality, Monodromy and Integrability of Two Dimensional String Effective Action
Das, A; Melikyan, A; Das, Ashok
2002-01-01
The monodromy matrix, ${\\hat{\\cal M}}$, is constructed for two dimensional tree level string effective action. The pole structure of ${\\hat{\\cal M}}$ is derived using its factorizability property. It is found that the monodromy matrix transforms non-trivially under the non-compact T-duality group, which leaves the effective action invariant and this can be used to construct the monodromy matrix for more complicated backgrounds starting from simpler ones. We construct, explicitly, ${\\hat{\\cal M}}$ for the exactly solvable Nappi-Witten model, both when B=0 and $B\
Boundary Conditions for NHEK through Effective Action Approach
Institute of Scientific and Technical Information of China (English)
CHEN Bin; NING Bo; ZHANG Jia-Ju
2012-01-01
We study the asymptotic symmetry group (ASG) of the near horizon geometry of extreme Kerr black hole through the effective action approach developed by Porfyriadis and Wilczek (arXiv:1007.1031v1[gr qc]).By requiring a finite boundary effective action,we derive a new set of asymptotic Killing vectors and boundary conditions,which are much more relaxed than the ones proposed by Matsuo Y et al.[Nucl.Phys.B 825 (2010) 231],and still allow a copy of a conformal group as its ASG.In the covariant formalism,the asymptotic charges are finite,with the corresponding central charge vanishing.By using the quasi-local charge and introducing a plausible cut-off,we find that the higher order terms of the asymptotic Killing vectors,which could not be determined through the effective action approach,contribute to the central charge as well.We also show that the boundary conditions suggested by Guica et al.[Phys.Rev.D 80 (2009)124008] lead to a divergent first-order boundary effective action.%We study the asymptotic symmetry group (ASG) of the near horizon geometry of extreme Kerr black hole through the effective action approach developed by Porfyriadis and Wilczek (arXiv:1007.1031vl[gr qc]). By requiring a finite boundary effective action, we derive a new set of asymptotic Killing vectors and boundary conditions, which are much more relaxed than the ones proposed by Matsuo Y et al. [Nucl. Phys. B 825 (2010) 231], and still allow a copy of a conformal group as its ASG. In the covariant formalism, the asymptotic charges are finite, with the corresponding central charge vanishing. By using the quasi-local charge and introducing a plausible cut-off, we find that the higher order terms of the asymptotic Killing vectors, which could not be determined through the effective action approach, contribute to the central charge as well. We also show that the boundary conditions suggested by Guica et al. [Phys. Rev. D 80 (2009) 124008] lead to a divergent first-order boundary effective action.
Effective action approach to wave propagation in scalar QED plasmas
Shi, Yuan; Qin, Hong
2016-01-01
A relativistic quantum field theory with nontrivial background fields is developed and applied to study waves in plasmas. The effective action of the electromagnetic 4-potential is calculated ab initio from the standard action of scalar QED using path integrals. The resultant effective action is gauge invariant and contains nonlocal interactions, from which gauge bosons acquire masses without breaking the local gauge symmetry. To demonstrate how the general theory can be applied, we study a cold unmagnetized plasma and a cold uniformly magnetized plasma. Using these two examples, we show that all linear waves well-known in classical plasma physics can be recovered from relativistic quantum results when taking the classical limit. In the opposite limit, classical wave dispersion relations are modified substantially. In unmagnetized plasmas, longitudinal waves propagate with nonzero group velocities even when plasmas are cold. In magnetized plasmas, anharmonically spaced Bernstein waves persist even when plasma...
Effective Lagrangian of SU(2) Yang-Mills Theory in the Presence of Fermions
Institute of Scientific and Technical Information of China (English)
FAN Ji-Yang; JIANG Ying; ZHU Zhong-Yuan
2002-01-01
We derive the one-loop effective action of SU(2) Yang Mills theory in the presence of fermions in the lowenergy limit. This result is presented by separating the topological degrees, which describe the non-Abelian monopolesfrom the dynamical degrees of the gauge potential and integrate out all the dynamical degrees and fermions in SU(2)Yang-Mills theory.
Action Research: Effective Marketing Strategies for a Blended University Program
Cook, Ruth Gannon; Ley, Kathryn
2008-01-01
This action research study investigated a marketing plan based on collaboration among a program faculty team and other organizational units for a graduate professional program. From its inception through the second year of operation, program enrollment increased due to the marketing plan based on an effective approach grounded in simple marketing…
Effects of Action Relations on the Configural Coding between Objects
Riddoch, M. J.; Pippard, B.; Booth, L.; Rickell, J.; Summers, J.; Brownson, A.; Humphreys, G. W.
2011-01-01
Configural coding is known to take place between the parts of individual objects but has never been shown between separate objects. We provide novel evidence here for configural coding between separate objects through a study of the effects of action relations between objects on extinction. Patients showing visual extinction were presented with…
Solution-generating transformations and the string effective action
Bergshoeff, E; Janssen, B; Ortin, T
1996-01-01
We study exhaustively the solution-generating transformations (dualities) that occur in the context of the low-energy effective action of superstring theory. We first consider target-space duality ('T duality') transformations in the absence of vector fields. We find that for one isometry the full d
The background effective average action approach to quantum gravity
DEFF Research Database (Denmark)
D’Odorico, G.; Codello, A.; Pagani, C.
2016-01-01
of an UV attractive non-Gaussian fixed-point, which we find characterized by real critical exponents. Our closure method is general and can be applied systematically to more general truncations of the gravitational effective average action. © Springer International Publishing Switzerland 2016....
Action Research: Effective Marketing Strategies for a Blended University Program
Cook, Ruth Gannon; Ley, Kathryn
2008-01-01
This action research study investigated a marketing plan based on collaboration among a program faculty team and other organizational units for a graduate professional program. From its inception through the second year of operation, program enrollment increased due to the marketing plan based on an effective approach grounded in simple marketing…
Two-Loop Gluon Regge Trajectory from Lipatov's Effective Action
Chachamis, Grigorios; Madrigal, José Daniel; Vera, Agustín Sabio
2012-01-01
Lipatov's high-energy effective action is a useful tool for computations in the Regge limit beyond leading order. Recently, a regularisation/subtraction prescription has been proposed that allows to apply this formalism to calculate next-to-leading order corrections in a consistent way. We illustrate this procedure with the computation of the gluon Regge trajectory at two loops.
Effect and mode of action of some systemic nematicides
Bunt, J.A.
1975-01-01
In this study, nematicidal effects, mode of action and specific characters of some systemic nematicides were studied, in search of substitutes for the widely used soil fumigants that require high dosages. The thesis comprises:- a review of literature,- development of techniques,- a test for nematici
Constraining the effective action by a method of external sources
Garbrecht, Bjorn
2015-01-01
We propose a novel method of evaluating the effective action, wherein the physical one- and two-point functions are obtained in the limit of non-vanishing external sources. We illustrate the self-consistency of this method by recovering the usual 2PI effective action due to Cornwall, Jackiw and Tomboulis, differing only by the fact that the saddle-point evaluation of the path integral is performed along the extremal quantum, rather than classical, path. As such, this approach is of particular relevance to situations where the dominant quantum and classical paths are non-perturbatively far away from one-another. A pertinent example is the decay of false vacua in radiatively-generated potentials, as may occur for the electroweak vacuum of the Standard Model. In addition, we describe how the external sources may instead be chosen so as to yield the two-particle-point-irreducible (2PPI) effective action of Coppens and Verschelde. Finally, in the spirit of the symmetry-improved effective action of Pilaftsis and Te...
BEPS Action 2: Neutralizing the Effects on Hybrid Mismatch Arrangements
de Boer, R.; Marres, O.
2015-01-01
Curbing tax arbitrage is one of the main priorities of the Organization for Economic Cooperation and Development (OECD) (endorsed by the G20 and the G8) ever since the public debate on base erosion fully erupted. Neutralizing the effect of hybrid mismatch arrangements has become Action No. 2 of the
BEPS Action 2: Neutralizing the Effects on Hybrid Mismatch Arrangements
de Boer, R.; Marres, O.
2015-01-01
Curbing tax arbitrage is one of the main priorities of the Organization for Economic Cooperation and Development (OECD) (endorsed by the G20 and the G8) ever since the public debate on base erosion fully erupted. Neutralizing the effect of hybrid mismatch arrangements has become Action No. 2 of the
Effective QED Actions Representations, Gauge Invariance, Anomalies and Mass Expansions
Deser, Stanley D; Seminara, D
1998-01-01
We analyze and give explicit representations for the effective abelian vector gauge field actions generated by charged fermions with particular attention to the thermal regime in odd dimensions, where spectral asymmetry can be present. We show, through $\\zeta-$function regularization, that both small and large gauge invariances are preserved at any temperature and for any number of fermions at the usual price of anomalies: helicity/parity invariance will be lost in even/odd dimensions, and in the latter even at zero mass. Gauge invariance dictates a very general ``Fourier'' representation of the action in terms of the holonomies that carry the novel, large gauge invariant, information. We show that large (unlike small) transformations and hence their Ward identities, are not perturbative order-preserving, and clarify the role of (properly redefined) Chern-Simons terms in this context. From a powerful representation of the action in terms of massless heat kernels, we are able to obtain rigorous gauge invariant...
Action co-representation: the joint SNARC effect.
Atmaca, Silke; Sebanz, Natalie; Prinz, Wolfgang; Knoblich, Günther
2008-01-01
Traditionally, communication has been defined as the intentional exchange of symbolic information between individuals. In contrast, the mirror system provides a basis for nonsymbolic and nonintentional information exchange between individuals. We believe that understanding the role of the mirror system in joint action has the potential to serve as a bridge between these two domains. The present study investigates one crucial component of joint action: the ability to represent others' potential actions in the same way as one's own in the absence of perceptual evidence. In two experiments a joint spatial numerical association of response codes (SNARC) effect is demonstrated, providing further evidence that individuals form functionally equivalent representations of their own and others' potential actions. It is shown that numerical (symbolic) stimuli that are mapped onto a spatially arranged internal representation (a mental number line) can activate a co-represented action in the same way as spatial stimuli. This generalizes previous results on co-representation.We discuss the role of the mirror system in co-representation as a basis for shared intentionality and communication.
Action video game training reduces the Simon Effect.
Hutchinson, Claire V; Barrett, Doug J K; Nitka, Aleksander; Raynes, Kerry
2016-04-01
A number of studies have shown that training on action video games improves various aspects of visual cognition including selective attention and inhibitory control. Here, we demonstrate that action video game play can also reduce the Simon Effect, and, hence, may have the potential to improve response selection during the planning and execution of goal-directed action. Non-game-players were randomly assigned to one of four groups; two trained on a first-person-shooter game (Call of Duty) on either Microsoft Xbox or Nintendo DS, one trained on a visual training game for Nintendo DS, and a control group who received no training. Response times were used to contrast performance before and after training on a behavioral assay designed to manipulate stimulus-response compatibility (the Simon Task). The results revealed significantly faster response times and a reduced cost of stimulus-response incompatibility in the groups trained on the first-person-shooter game. No benefit of training was observed in the control group or the group trained on the visual training game. These findings are consistent with previous evidence that action game play elicits plastic changes in the neural circuits that serve attentional control, and suggest training may facilitate goal-directed action by improving players' ability to resolve conflict during response selection and execution.
Norm theory and the action-effect: The role of social norms in regret following action and inaction
Feldman, Gilad; Albarracín, Dolores
2016-01-01
The action-effect (Kahneman & Tversky, 1982) is one of the most widely cited and replicated effects in the regret literature, showing that negative outcomes are regretted more when they are a result of action compared to inaction. Building on theoretical arguments by norm theory (Kahneman & Miller,
Exceptional F(4) Higher-Spin Theory in AdS(6) at One-Loop and other Tests of Duality
Gunaydin, Murat; Tran, Tung
2016-01-01
We study the higher-spin gauge theory in six-dimensional anti-de Sitter space $AdS_6$ that is based on the exceptional Lie superalgebra $F(4)$. The relevant higher-spin algebra was constructed in arXiv:1409.2185 [hep-th]. We determine the spectrum of the theory and show that it contains the physical fields of the Romans $F(4)$ gauged supergravity. The full spectrum consists of an infinite tower of unitary supermultiplets of $F(4)$ which extend the Romans multiplet to higher spins plus a single short supermultiplet. Motivated by applications to this novel supersymmetric higher-spin theory as well as to other theories, we extend the known one-loop tests of $AdS/CFT$ duality in various directions. The spectral zeta-function is derived for the most general case of fermionic and mixed-symmetry fields, which allows one to test the Type-A and B theories and supersymmetric extensions thereof in any dimension. We also study higher-spin doubletons and partially-massless fields. While most of the tests are successfully ...
Exceptional F(4) higher-spin theory in AdS{sub 6} at one-loop and other tests of duality
Energy Technology Data Exchange (ETDEWEB)
Günaydin, Murat [Institute for Gravitation and the Cosmos Physics Department, Pennsylvania State University, University Park, PA 16802 (United States); Skvortsov, Evgeny [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians University Munich, Theresienstr. 37, D-80333 Munich (Germany); Lebedev Institute of Physics, Leninsky ave. 53, 119991 Moscow (Russian Federation); Tran, Tung [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States)
2016-11-28
We study the higher-spin gauge theory in six-dimensional anti-de Sitter space AdS{sub 6} that is based on the exceptional Lie superalgebra F(4). The relevant higher-spin algebra was constructed in http://arxiv.org/abs/1409.2185. We determine the spectrum of the theory and show that it contains the physical fields of the Romans F(4) gauged supergravity. The full spectrum consists of an infinite tower of unitary supermultiplets of F(4) which extend the Romans multiplet to higher spins plus a single short supermultiplet. Motivated by applications to this novel supersymmetric higher-spin theory as well as to other theories, we extend the known one-loop tests of AdS/CFT duality in various directions. The spectral zeta-function is derived for the most general case of fermionic and mixed-symmetry fields, which allows one to test the Type-A and B theories and supersymmetric extensions thereof in any dimension. We also study higher-spin doubletons and partially-massless fields. While most of the tests are successfully passed, the Type-B theory in all even dimensional anti-de Sitter spacetimes presents an interesting puzzle: the free energy as computed from the bulk is not equal to that of the free fermion on the CFT side, though there is some systematics to the discrepancy.
Effect of exercise on insulin action in human skeletal muscle
DEFF Research Database (Denmark)
Richter, Erik; Mikines, K J; Galbo, Henrik
1989-01-01
The effect of 1 h of dynamic one-legged exercise on insulin action in human muscle was studied in 6 healthy young men. Four hours after one-legged knee extensions, a three-step sequential euglycemic hyperinsulinemic clamp combined with arterial and bilateral femoral vein catheterization was perfo...... recovery of human skeletal muscle.......The effect of 1 h of dynamic one-legged exercise on insulin action in human muscle was studied in 6 healthy young men. Four hours after one-legged knee extensions, a three-step sequential euglycemic hyperinsulinemic clamp combined with arterial and bilateral femoral vein catheterization...... consumption and at some insulin concentrations on potassium exchange. In contrast, no change in insulin effects on limb exchange of free fatty acids, glycerol, alanine or tyrosine were found after exercise. Glycogen concentration in rested vastus lateralis muscle did not increase measurably during the clamp...
Covariant effective action for a Galilean invariant quantum Hall system
Geracie, Michael; Prabhu, Kartik; Roberts, Matthew M.
2016-09-01
We construct effective field theories for gapped quantum Hall systems coupled to background geometries with local Galilean invariance i.e. Bargmann spacetimes. Along with an electromagnetic field, these backgrounds include the effects of curved Galilean spacetimes, including torsion and a gravitational field, allowing us to study charge, energy, stress and mass currents within a unified framework. A shift symmetry specific to single constituent theories constraints the effective action to couple to an effective background gauge field and spin connection that is solved for by a self-consistent equation, providing a manifestly covariant extension of Hoyos and Son's improvement terms to arbitrary order in m.
Misunderstanding that the Effective Action is Convex under Broken Symmetry
Asanuma, Nobu-Hiko
2016-01-01
The widespread belief that the effective action is convex and has a flat bottom under broken global symmetry is shown to be wrong. We show spontaneous symmetry breaking necessarily accompanies non-convexity in the effective action for quantum field theory, or in the free energy for statistical mechanics, and clarify the magnitude of non-convexity. For quantum field theory, it is also explicitly proved that translational invariance breaks spontaneously when the system is in the non-convex region, and that different vacua of spontaneously broken symmetry cannot be superposed. As applications of non-convexity, we study the first-order phase transition which happens at the zero field limit of spontaneously broken symmetry, and we propose a simple model of phase coexistence which obeys the Born rule.
Gauge symmetry breaking in gravity and auxiliary effective action
Akhavan, Amin
2017-02-01
In the context of the covariant symmetry breaking in gravity, we study the quantum aspect of Chamseddine-Mukhanov model by making use of path integral method. Utilizing one of the gauge fixing constraints, we remove the specific ghost degree of freedom. In continuation, we define an auxiliary effective action. Introducing an auxiliary field, we will have a new dynamic field in addition to the fundamental field.
Topics In Gauge Theory (effective Action, Quantum Electrodynamics, Chern Simons)
Hall, T M
1998-01-01
This dissertation will present studies in three distinct areas of gauge theories. In Chern-Simons theories, the fate of the quantized Chern-Simons coupling constant upon renormalization of the theory is investigated. We find the Chern-Simons coupling constant remains quantized in the presence of residual non-abelian gauge symmetry. A two-flavor model of fermions is studied to determine the extent at which the vacuum condensate is locally proportional to the magnetic field. We find the proportionality is local in the limit of large flux. Using resolvent techniques, we find the exact effective action in a single pulsed electric background gauge field $E\\sb1$(t) = Esech $\\sp2$($t\\over r$). We derive the zero and first order derivative expansion for this electric field and compare with our exact results. Dispersion relations between the real and imaginary parts of the exact effective action are derived. In a uniform semi-classical approximation, we find the exact effective action for a spatially homogeneous backg...
Brane Effective Actions, Kappa-Symmetry and Applications
Directory of Open Access Journals (Sweden)
Joan Simón
2012-02-01
Full Text Available This is a review on brane effective actions, their symmetries and some of their applications. Its first part covers the Green–Schwarz formulation of single M- and D-brane effective actions focusing on kinematical aspects: the identification of their degrees of freedom, the importance of world volume diffeomorphisms and kappa symmetry to achieve manifest spacetime covariance and supersymmetry, and the explicit construction of such actions in arbitrary on-shell supergravity backgrounds. Its second part deals with applications. First, the use of kappa symmetry to determine supersymmetric world volume solitons. This includes their explicit construction in flat and curved backgrounds, their interpretation as Bogomol’nyi–Prasad–Sommerfield (BPS states carrying (topological charges in the supersymmetry algebra and the connection between supersymmetry and Hamiltonian BPS bounds. When available, I emphasise the use of these solitons as constituents in microscopic models of black holes. Second, the use of probe approximations to infer about the non-trivial dynamics of strongly-coupled gauge theories using the anti de Sitter/conformal field theory (AdS/CFT correspondence. This includes expectation values of Wilson loop operators, spectrum information and the general use of D-brane probes to approximate the dynamics of systems with small number of degrees of freedom interacting with larger systems allowing a dual gravitational description. Its final part briefly discusses effective actions for N D-branes and M2-branes. This includes both Super-Yang-Mills theories, their higher-order corrections and partial results in covariantising these couplings to curved backgrounds, and the more recent supersymmetric Chern–Simons matter theories describing M2-branes using field theory, brane constructions and 3-algebra considerations.
Using the Psychology of Language to Effectively Communicate Actionable Science
Hall, J. M.
2014-12-01
The words used to articulate science can have as significant a psychological impact on public perception as the data itself. It is therefore essential to utilize language that not only accurately relates the scientific information, but also effectively conveys a message that is congruent with the presenter's motivation for expressing the data. This is especially relevant for environmental subjects that are surrounded by emotionally charged, political discourses. For example are terms like catastrophe and disaster; while these words may accurately illustrate impartial scientific data, they will likely trigger psychological responses in audiences such as fear or denial that have a detrimental impact on the human decision making process. I propose a set of 5 key principles to assist in communicating data to the general public that both support the transfer of ideas and the presenter's intended psychological impact. 1) Articulate the underlying intentions that motivate the communication of data in a transparent manner 2) Use language congruent with the presenter's stated intentions 3) Maintain a neutral, non-judgmental attitude towards the complex human psychological and emotional dynamics present in a target audience 4) Demonstrate acceptance and compassion when analyzing past and present human actions that adversely affect the environment 5) Develop a perspective of non-attachment when proposing future actions and/or consequences of current human behaviors. The application of these 5 principles provides a framework to move from our current understanding of problems and solutions to effective physical action that allows us to gracefully adapt with our ever changing planet.
Braneworld effective action An alternative to Kaluza-Klein reduction
Barvinsky, A O; Rathke, A; Kiefer, C; Barvinsky, Andrei; Kamenshchik, Alexander; Rathke, Andreas; Kiefer, Claus
2003-01-01
We construct the braneworld effective action in the two-brane Randall-Sundrum model in a setup alternative to Kaluza-Klein reduction: The action is written as a functional of the two metric and radion fields on the branes. In the low-energy spectrum of the model we find two - one massless and one massive - graviton modes, the mass of the massive mode diverging in the limit of merging branes. Our results confirm a recently proposed model of braneworld inflation with diverging branes. They also suggest the possibility of a new mechanism for a repulsive interbrane potential which can underlie the model of colliding "thick" branes in the Big Crunch/Big Bang transitions in cosmology. Mixing of the obtained massless and massive modes can be interpreted as radion-induced graviton oscillations potentially interesting for gravitational wave astronomy.
Highly Effective Action from Large N Gauge Fields
Yang, Hyun Seok
2014-01-01
Recently John H. Schwarz put forward a conjecture that the world-volume action of a probe $D3$-brane in an AdS5 x S5 background of type IIB superstring theory can be reinterpreted as the highly effective action (HEA) of four-dimensional N=4 superconformal field theory on the Coulomb branch. We argue that the HEA can be derived from the noncommutative (NC) field theory representation of the AdS/CFT correspondence and the Seiberg-Witten (SW) map defining a spacetime field redefinition between ordinary and NC gauge fields. It is based only on the well-known facts that the master fields of large N matrices are higher-dimensional NC U(1) gauge fields and the SW map is a local coordinate transformation eliminating U(1) gauge fields known as the Darboux theorem in symplectic geometry.
Covariant Derivation of Effective Actions for SUSY Topological Defects
París, J; Roca, Jaume
1998-01-01
We make a first step to extend to the supersymmetric arena the effective action method, which is used to covariantly deduce the low energy dynamics of topological defects directly from their parent field theory. By focussing on two-dimensional supersymmetric theories we are able to derive the appropriate change of variables that singles out the low energy degrees of freedom. These correspond to super-worldline embeddings in superspace which are subject to a geometrical constraint. We obtain a supersymmetric and $\\kappa$--invariant low energy expansion, with the standard superparticle action as the leading term, which can be used for the determination of higher-order corrections. Our formulation fits quite naturally with the present geometrical description of also provides a basis for the exploration of these issues in higher-dimensional supersymmetric theories.
Directory of Open Access Journals (Sweden)
Takahiro eKawabe
2013-09-01
Full Text Available Humans can acquire the statistical features of the external world and employ them to control behaviors. Some external events occur in harmony with an agent’s action, and thus humans should also be able to acquire the statistical features between an action and its external outcome. We report that the acquired action-outcome statistical features alter the visual appearance of the action outcome. Pressing either of two assigned keys triggered visual motion whose direction was statistically biased either upward or downward, and observers judged the stimulus motion direction. Points of subjective equality (PSE for judging motion direction were shifted repulsively from the mean of the distribution associated with each key. Our Bayesian model accounted for the PSE shifts, indicating the optimal acquisition of the action-effect statistical relation. The PSE shifts were moderately attenuated when the action-outcome contingency was reduced. The Bayesian model again accounted for the attenuated PSE shifts. On the other hand, when the action-outcome contiguity was greatly reduced, the PSE shifts were greatly attenuated, and however, the Bayesian model could not accounted for the shifts. The results indicate that visual appearance can be modified by prediction based on the optimal acquisition of action-effect causal relation.
PARENTS' AUTHORITY AND THE EFFECTIVENESS OF THEIR EDUCATIONAL ACTIONS
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Romanowska-Tolloczko Anna
2010-01-01
Full Text Available Facing a gradual crisis of moral authority in the modern world, educationalists underline its importance in the education and upbringing process. The first and, for a long period of time, the most important authority for children are their parents, who often fail to understand the nature of their own significance and impact on the child. They often wrongly associate parental authority with unquestionable power and this faulty reasoning carries negative developmental implications as the child's submissiveness is not tantamount to acceptance and may result from his/her weakness or fear rather than from recognizing parental authority. This article is to emphasise that parents need to be fully aware of their own educational actions in the child upbringing process. It is important to understand that such actions affect the way parents are perceived by children. This article suggests a number of behaviours conducive to building and sustaining the sense of authority and respect as these features are fundamental in ensuring the effectiveness of educational actions undertaken by parents in the upbringing process.
Dilaton Effective Action with $\\mathcal{N}=1$ Supersymmetry
Bobev, Nikolay; Olson, Timothy M
2013-01-01
We clarify the structure of the four-dimensional low-energy effective action that encodes the conformal and $U(1)$ R-symmetry anomalies in an $\\mathcal{N}=1$ supersymmetric field theory. The action depends on the dilaton, $\\tau$, associated with broken conformal symmetry, and the Goldstone mode, $\\beta$, of the broken $U(1)$ R-symmetry. We present the action for general curved spacetime and background gauge field up to and including all possible four-derivative terms. The result, constructed from basic principles, extends and clarifies the structure found by Schwimmer and Theisen in arXiv:1011.0696 using superfield methods. We show that the Goldstone mode $\\beta$ does not interfere with the proof of the four-dimensional $a$-theorem based on $2 \\to 2$ dilaton scattering. In fact, supersymmetry Ward identities ensure that a proof of the $a$-theorem can also be based on $2 \\to 2$ Goldstone mode scattering when the low-energy theory preserves $\\mathcal{N}=1$ supersymmetry. We find that even without supersymmetry,...
Hammant, T C; von Hippel, G M; Horgan, R R; Monahan, C J
2013-01-01
We apply the background field (BF) method to Non-Relativistic QCD (NRQCD) on the lattice in order to determine the one-loop radiative corrections to the coefficients of the NRQCD action in a manifestly gauge-covariant manner by matching the NRQCD prediction for particular on-shell processes with those of relativistic continuum QCD. We explain how the BF method is implemented in automated perturbation theory and discuss the technique for matching the relativistic and non-relativistic theories. We compute the one-loop radiative corrections to the sigma.B and Darwin terms for the NRQCD action currently used in simulations, as well as the one-loop coefficients of the spin-dependent O(alpha^2) four-fermion contact terms. The effect of the corrections on the hyperfine splitting of bottomonium is estimated using earlier simulation results; the corrected lattice prediction is found to be in agreement with experiment. Agreement of the hyperfine splitting of bottomonium and the B-meson system is confirmed by recent sim...
Bending effects on lasing action of semiconductor nanowires.
Yang, Weisong; Ma, Yaoguang; Wang, Yipei; Meng, Chao; Wu, Xiaoqin; Ye, Yu; Dai, Lun; Tong, Limin; Liu, Xu; Yang, Qing
2013-01-28
High flexibility has been one of advantages for one-dimensional semiconductor nanowires (NWs) in wide application of nanoscale integrated circuits. We investigate the bending effects on lasing action of CdSe NWs. Threshold increases and differential efficiency decreases gradually when we decrease the bending radius step by step. Red shift and mode reduction in the output spectra are also observed. The bending loss of laser oscillation is considerably larger than that of photoluminescence (PL), and both show the exponential relationship with the bending radius. Diameter and mode dependent bending losses are investigated. Furthermore, the polarizations of output can be modulated linearly by bending the NWs into different angles continuously.
Effective action for the Regge processes in gravity
Energy Technology Data Exchange (ETDEWEB)
Lipatov, L.N. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation); Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
2011-05-15
It is shown, that the effective action for the reggeized graviton interactions can be formulated in terms of the reggeon fields A{sup ++} and A{sup --} and the metric tensor g{sub {mu}}{sub {nu}} in such a way, that it is local in the rapidity space and has the property of general covariance. The corresponding effective currents j{sup -} and j{sup +} satisfy the Hamilton-Jacobi equation for a massless particle moving in the gravitational field. These currents are calculated explicitly for the shock wave-like fields and a variation principle for them is formulated. As an application, we reproduce the effective lagrangian for the multi-regge processes in gravity together with the graviton Regge trajectory in the leading logarithmic approximation with taking into account supersymmetric contributions. (orig.)
Observation of Simple Intransitive Actions: The Effect of Familiarity
Plata Bello, Julio; Modroño, Cristián; Marcano, Francisco; González–Mora, José Luis
2013-01-01
Introduction Humans are more familiar with index – thumb than with any other finger to thumb grasping. The effect of familiarity has been previously tested with complex, specialized and/or transitive movements, but not with simple intransitive ones. The aim of this study is to evaluate brain activity patterns during the observation of simple and intransitive finger movements with differing degrees of familiarity. Methodology A functional Magnetic Resonance Imaging (fMRI) study was performed using a paradigm consisting of the observation of 4 videos showing a finger opposition task between the thumb and the other fingers (index, middle, ring and little) in a repetitive manner with a fixed frequency (1 Hz). This movement is considered as the pantomime of a precision grasping action. Results Significant activity was identified in the bilateral Inferior Parietal Lobule and premotor regions with the selected level of significance (FDR [False Discovery Rate] = 0.01). The extent of the activation in both regions tended to decrease when the finger that performed the action was further from the thumb. More specifically, this effect showed a linear trend (index>middle>ring>little) in the right parietal and premotor regions. Conclusions The observation of less familiar simple intransitive movements produces less activation of parietal and premotor areas than familiar ones. The most important implication of this study is the identification of differences in brain activity during the observation of simple intransitive movements with different degrees of familiarity. PMID:24073213
Constraining gravitational interactions in the M theory effective action
Basu, Anirban
2013-01-01
We consider purely gravitational interactions of the type D^{2k} R^4 in the effective action of M theory in 11 dimensional flat spacetime, where k \\geq 0. The duality between M theory on S^1 and type IIA string theory, and the structure of the dilaton dependence of string amplitudes, show that the only non-vanishing interactions in the M theory effective action have k=3n. The coefficient of the D^{6n} R^4 interaction in M theory is determined by the genus (n+1) string amplitude of the D^{6n} R^4 interaction in the type IIA theory. Focussing on the even-even spin structure part of the type IIA string amplitude, this coefficient is given by the type IIB genus (n+1) amplitude, which we constrain using supersymmetry, S-duality and maximal supergravity. The source terms of the Poisson equations satisfied by the S-duality invariant IIB couplings play a central role in the analysis. This procedure yields partial contributions to several multi-loop type IIB string amplitudes, from which we extract the coefficients of...
SYNERGIC EFFECT OF THE ACTION OF OPERATIONAL AND FINANCIAL RISK
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MELANIA ELENA MICULEAC
2014-10-01
Full Text Available This paper allows us to understand the complex action of total risk at microeconomic level, taking into account several factors: the area in which it acts: the operating activity, generating an economic risk, and the financing activity, generating a financial risk; the nature of the observed indicators: the nature of the profit and the nature of the cash; the synergic effect of the action of operational and financial risk, resulting the total risk. We consider that the innovative value of the article resides in the suggested model of correlation between the activity volume and the capital structure, because different approaches give different results, that is why we suggest a unitary approach, a more pragmatic one of the phenomenon. Also, we established the phases observed in order to establish the global profitability threshold of an international corporation which develops activities in several sectors, through several branches. In this article we have used the method of real leverage which measures the total risk of a company by mixing the operating leverage with the financial leverage.
Dura’s Effect on Securities Class Actions
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Scotland M. Duncan
2008-12-01
Full Text Available On April 19, 2005, the United States Supreme Court rendered a unanimous decision in Dura Pharmaceuticals, Inc. v. Broudo, which had been described as “the most important securities case in a decade.” Simply put, the decision raises the pleading standard for Rule 10b-5 cases asserting fraud-onthe-market; instead of requiring a showing of ex ante losses, such as inflation at the time of purchase, Dura requires a showing of ex post losses, such as market decline resulting from a corrective disclosure. This paper assesses the decision’s practical implications by examining and empirically testing whether the Supreme Court’s enhanced pleading requirements have impacted the frequency and magnitude of post-Reform Act (PSLRA class action securities cases. Specifically, this paper examines Dura’s effect on the filing and settling of cases, as well as on settlement amount. In particular, the results suggest that Dura, ceteris paribus, has had a statistically significant impact on both the filing and settlement of class actions, suggesting a reduction in frivolous litigation.
Theoretical results on the effect of `shortcut' actions in MDPs
McCarthy, Sara M.; Precup, Doina
2014-04-01
Temporally extended actions have been used extensively in reinforcement learning in order to speed up the process of learning good behaviours. While such actions are intuitively appealing, very little work has provided a formal analysis of the advantage that can be obtained by using such actions. In this paper, we tackle this problem using the methodology of stochastic processes. We present case studies of Markov decision processes with actions that allow 'shortcuts' between different parts of the environment, and show how such actions affect the travel time between states. Our main finding is that such actions allow for provably quicker travel around the environment, and the benefit increases with the dimensionality of the state space. Hence, extended actions help in efficiently exploring large, high-dimensional domains.
Effective action and vacuum expectations in nonlinear $\\sigma$ model
Fayzullaev, B A
2015-01-01
The equations for effective action for nonlinear $\\sigma$ model are derived using DeWitt method in two forms - for generator of vertex parts $\\Gamma$ and for generator of weakly connected parts $W$. Loop-expansion solutions to these equations are found. It is shown that vacuum expectation values for various quantities including divergence of a N\\"{o}ther current, trace of the energy-momentum tensor and so on, can be calculated by this method. Also it is shown that vacuum expectation to the sigma-field is determined by an explicit combination of tree Green function and classical solution. It is shown that the limit when coupling constant tends to zero is singular one.
Effective action in a higher-spin background
Bekaert, Xavier; Mourad, Jihad
2010-01-01
We consider a free massless scalar field coupled to an infinite tower of background higher-spin gauge fields via minimal coupling to the traceless conserved currents. The set of Abelian gauge transformations is deformed to the non-Abelian group of unitary operators acting on the scalar field. The gauge invariant effective action is computed perturbatively in the external fields. The structure of the various (divergent or finite) terms is determined. In particular, the quadratic part of the logarithmically divergent (or of the finite) term is expressed in terms of curvatures and related to conformal higher-spin gravity. The generalized higher-spin Weyl anomalies are also determined. The relation with the theory of interacting higher-spin gauge fields on anti de Sitter spacetime via the holographic correspondence is discussed.
Mephedrone: Public health risk, mechanisms of action, and behavioral effects.
Dybdal-Hargreaves, Nicholas F; Holder, Nicholas D; Ottoson, Paige E; Sweeney, Melanie D; Williams, Tyisha
2013-08-15
The recent shortage of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) has led to an increased demand for alternative amphetamine-like drugs such as the synthetic cathinone, 4-methylmethcathinone (mephedrone). Despite the re-classification of mephedrone as a Class B restricted substance by the United Kingdom and restrictive legislation by the United States, international policy regarding mephedrone control is still developing and interest in synthetic amphetamine-like drugs could drive the development of future mephedrone analogues. Currently, there is little literature investigating the mechanism of action and long-term effects of mephedrone. As such, we reviewed the current understanding of amphetamines, cathinones, and cocaine emphasizing the potentially translational aspects to mephedrone, as well as contrasting with the work that has been done specifically on mephedrone in order to present the current state of understanding of mephedrone in terms of its risks, mechanisms, and behavioral effects. Emerging research suggests that while there are structural and behavioral similarities of mephedrone with amphetamine-like compounds, it appears that serotonergic signaling may mediate more of mephedrone's effects unlike the more dopaminergic dependent effects observed in traditional amphetamine-like compounds. As new designer drugs are produced, current and continuing research on mephedrone and other synthetic cathinones should help inform policymakers' decisions regarding the regulation of novel 'legal highs.'
47 CFR 1.102 - Effective dates of actions taken pursuant to delegated authority.
2010-10-01
... delegated authority. 1.102 Section 1.102 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL... by the Commission and Pursuant to Delegated Authority; Effective Dates and Finality Dates of Actions § 1.102 Effective dates of actions taken pursuant to delegated authority. (a) Final actions following...
Wiggett, Alison J.; Hudson, Matt; Tipper, Steve P.; Downing, Paul E.
2011-01-01
Observation of another person executing an action primes the same action in the observer's motor system. Recent evidence has shown that these priming effects are flexible, where training of new associations, such as making a foot response when viewing a moving hand, can reduce standard action priming effects (Gillmeister, Catmur, Liepelt, Brass,…
43 CFR 46.115 - Consideration of past actions in the analysis of cumulative effects.
2010-10-01
... Environmental Quality § 46.115 Consideration of past actions in the analysis of cumulative effects. When... Memorandum on Consideration of Past Actions in Cumulative Effects Analysis” dated June 24, 2005, or any... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Consideration of past actions in...
Ecological effects of contaminants and remedial actions in Bear Creek
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Southworth, G.R.; Loar, J.M.; Ryon, M.G.; Smith, J.G.; Stewart, A.J. (Oak Ridge National Lab., TN (United States)); Burris, J.A. (C. E. Environmental, Inc., Tallahassee, FL (United States))
1992-01-01
Ecological studies of the Bear Creek watershed, which drains the area surrounding several Oak Ridge Y-12 Plant waste disposal facilities, were initiated in May 1984 and are continuing at present. These studies consisted of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek, and they were followed by a presently ongoing monitoring phase that involves reduced sampling intensities. The characterization phase utilized two approaches: (1) instream sampling of benthic invertebrate and fish communities in Bear Creek to identify spatial and temporal patterns in distribution and abundance and (2) laboratory bioassays on water samples from Bear Creek and selected tributaries to identify potential sources of toxicity to biota. The monitoring phase of the ecological program relates to the long-term goals of identifying and prioritizing contaminant sources and assessing the effectiveness of remedial actions. It continues activities of the characterization phase at less frequent intervals. The Bear Greek Valley is a watershed that drains the area surrounding several closed Oak Ridge Y-12 Plant waste disposal facilities. Past waste disposal practices in Bear Creek Valley resulted in contamination of Bear Creek and consequent ecological damage. Extensive remedial actions have been proposed at waste sites, and some of the have been implemented or are now underway. The proposed study plan consists of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek in the first year followed by a reduction in sampling intensity during the monitoring phase of the plan. The results of sampling conducted from May 1984 through early 1989 are presented in this report.
Non-abelian action of D0-branes from Matrix theory in the longitudinal 5-brane background
Energy Technology Data Exchange (ETDEWEB)
Asano, Masako E-mail: asano@hep-th.phys.s.u-tokyo.ac.jp; Sekino, Yasuhiro E-mail: sekino@th.phys.titech.ac.jp
2002-09-09
We study one-loop effective action of Berkooz-Douglas Matrix theory and obtain non-abelian action of D0-branes in the background field produced by longitudinal 5-branes. Since these 5-branes do not have D0-brane charge and are not present in BFSS Matrix theory, our analysis provides an independent test for the coupling of D-branes to general weak backgrounds proposed by Taylor and Van Raamsdonk from the analysis of the BFSS model. The proposed couplings appear in the Berkooz-Douglas effective action precisely as expected, which suggests the consistency of the two matrix models. We also point out the existence of the terms which are not given by the symmetrized trace prescription in the Matrix theory effective action.
Effects of action video game training on visual working memory.
Blacker, Kara J; Curby, Kim M; Klobusicky, Elizabeth; Chein, Jason M
2014-10-01
The ability to hold visual information in mind over a brief delay is critical for acquiring information and navigating a complex visual world. Despite the ubiquitous nature of visual working memory (VWM) in our everyday lives, this system is fundamentally limited in capacity. Therefore, the potential to improve VWM through training is a growing area of research. An emerging body of literature suggests that extensive experience playing action video games yields a myriad of perceptual and attentional benefits. Several lines of converging work suggest that action video game play may influence VWM as well. The current study utilized a training paradigm to examine whether action video games cause improvements to the quantity and/or the quality of information stored in VWM. The results suggest that VWM capacity, as measured by a change detection task, is increased after action video game training, as compared with training on a control game, and that some improvement to VWM precision occurs with action game training as well. However, these findings do not appear to extend to a complex span measure of VWM, which is often thought to tap into higher-order executive skills. The VWM improvements seen in individuals trained on an action video game cannot be accounted for by differences in motivation or engagement, differential expectations, or baseline differences in demographics as compared with the control group used. In sum, action video game training represents a potentially unique and engaging platform by which this severely capacity-limited VWM system might be enhanced.
Regulation of international energy markets: Economic effects of political actions
Shcherbakova, Anastasia V.
Recent increases in volatility of energy prices have led many governments to reevaluate their regard of national energy reserves and reconsider future exploration, production, and consumption patterns. The flurry of activity that has been generated by such price volatility has included large-scale nationalizations of energy sectors, unilateral renegotiations of foreign energy development contracts, and expropriations of resources from foreign energy firms on one hand, and on the other hand more rapid energy sector liberalization, intensified search for and development of renewable fuels and technologies, and development of incentives for increased energy efficiency and conservation. The aim of this dissertation is to examine and quantify the extent of positive and negative effects that have resulted from some of these activities. The first chapter focuses on quantifying the effect that nationalistic sentiment has had on economic attractiveness of energy sectors during the decade prior to the recent global economic crisis, as measured by foreign direct investment (FDI) inflows. Empirical results demonstrate that both political and economic conditions play an important role in investors' decisions. A combination of investment friendliness, corruption levels, and democracy all help to explain the trends in energy-sector investment levels over time in my sample countries, although differences in the types of corruption existing in these nations do not. Investment levels, in turn, appear to influence future levels of oil production, underscoring the significance of good investment policies for future success of energy sectors. Chapter two considers the response of energy stock prices to severe regulatory actions. It employs an event study framework to examine causal effects of critical informational announcements (i.e. events of expropriation and nationalization) on daily returns and cumulative losses in firm value of energy corporations. Results show that a firm
Effect of Composite Action on the Strength of Wood Roofs
Directory of Open Access Journals (Sweden)
Ivan A. Campos Varela
2015-01-01
Full Text Available Engineering certification for the installation of solar photovoltaic modules on wood roofs is often denied because existing wood roofs do not meet current building codes. Rather than requiring expensive structural retrofits, we desire to show that many roofs are actually sufficiently strong if the effect of composite action produced by joist-sheathing interaction is considered. In a series of laboratory experiments using a limited number of two-by-four wood joists with and without sheathing panels, conventionally sheathed stud-grade joists, surprisingly, exhibited between 18% and 63% higher nominal strength than similar bare joists. To explain this strength increase, a simple model was developed to predict the strengths of the nailed partially composite sections, but the model only justifies a 1.4% to 3.8% increase in bending strength of joists with an allowable bending strength of 1000 psi. More testing is indicated to resolve this discrepancy between laboratory results and analytical modeling results. In addition to elucidating nonlinear partial composite behavior of existing roof systems, this paper shows that, with minor changes in roof framing practices, strength increases of 70% or more are achievable, compared to the strengths of conventionally sheathed joists.
Polyphenols: Extraction Methods, Antioxidative Action, Bioavailability and Anticarcinogenic Effects
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Eva Brglez Mojzer
2016-07-01
Full Text Available Being secondary plant metabolites, polyphenols represent a large and diverse group of substances abundantly present in a majority of fruits, herbs and vegetables. The current contribution is focused on their bioavailability, antioxidative and anticarcinogenic properties. An overview of extraction methods is also given, with supercritical fluid extraction highlighted as a promising eco-friendly alternative providing exceptional separation and protection from degradation of unstable polyphenols. The protective role of polyphenols against reactive oxygen and nitrogen species, UV light, plant pathogens, parasites and predators results in several beneficial biological activities giving rise to prophylaxis or possibly even to a cure for several prevailing human diseases, especially various cancer types. Omnipresence, specificity of the response and the absence of or low toxicity are crucial advantages of polyphenols as anticancer agents. The main problem represents their low bioavailability and rapid metabolism. One of the promising solutions lies in nanoformulation of polyphenols that prevents their degradation and thus enables significantly higher concentrations to reach the target cells. Another, more practiced, solution is the use of mixtures of various polyphenols that bring synergistic effects, resulting in lowering of the required therapeutic dose and in multitargeted action. The combination of polyphenols with existing drugs and therapies also shows promising results and significantly reduces their toxicity.
Soft symmetry improvement of two particle irreducible effective actions
Brown, Michael J
2016-01-01
Two particle irreducible effective actions (2PIEAs) are valuable non-perturbative techniques in quantum field theory; however, finite truncations of them violate the Ward identities (WIs) of theories with spontaneously broken symmetries. The symmetry improvement (SI) method of Pilaftsis and Teresi attempts to overcome this by imposing the WIs as constraints on the solution; however the method suffers from the non-existence of solutions in linear response theory and in certain truncations in equilibrium. Motivated by this, we introduce a new method called soft symmetry improvement (SSI) which relaxes the constraint. Violations of WIs are allowed but punished in a least-squares implementation of the symmetry improvement idea. A new parameter $\\xi$ controls the strength of the constraint. The method interpolates between the unimproved ($\\xi \\to \\infty$) and SI ($\\xi \\to 0$) cases and the hope is that practically useful solutions can be found for finite $\\xi$. We study the SSI-2PIEA for a scalar O(N) model in the...
How and when auditory action effects impair motor performance.
D'Ausilio, Alessandro; Brunetti, Riccardo; Delogu, Franco; Santonico, Cristina; Belardinelli, Marta Olivetti
2010-03-01
Music performance is characterized by complex cross-modal interactions, offering a remarkable window into training-induced long-term plasticity and multimodal integration processes. Previous research with pianists has shown that playing a musical score is affected by the concurrent presentation of musical tones. We investigated the nature of this audio-motor coupling by evaluating how congruent and incongruent cross-modal auditory cues affect motor performance at different time intervals. We found facilitation if a congruent sound preceded motor planning with a large Stimulus Onset Asynchrony (SOA -300 and -200 ms), whereas we observed interference when an incongruent sound was presented with shorter SOAs (-200, -100 and 0 ms). Interference and facilitation, instead of developing through time as opposite effects of the same mechanism, showed dissociable time-courses suggesting their derivation from distinct processes. It seems that the motor preparation induced by the auditory cue has different consequences on motor performance according to the congruency with the future motor state the system is planning and the degree of asynchrony between the motor act and the sound presentation. The temporal dissociation we found contributes to the understanding of how perception meets action in the context of audio-motor integration.
Fine tuning and vacuum stability in Wilsonian effective action
Krajewski, Tomasz
2014-01-01
We have computed Wilsonian effective action in a simple model containing scalar field with quartic self-coupling which interacts via Yukawa coupling with a Dirac fermion. The model is invariant under a chiral parity operation, which can be spontaneously broken by a vev of the scalar field. We have computed explicitly Wilsonian running of relevant parameters which makes it possible to discuss in a consistent manner the issue of fine-tuning and stability of the scalar potential. This has been compared with the typical picture based on Gell-Mann-Low running. Since Wilsonian running includes automatically integration out of heavy degrees of freedom, the running differs markedly from the Gell-Mann-Low version. However, similar behaviour can be observed: scalar mass squared parameter and the quartic coupling can change sign from a positive to a negative one due to running which causes spontaneous symmetry breaking or an instability in the renormalizable part of the potential for a given range of scales. However, ca...
Lorentz-violating Euler-Heisenberg effective action
Furtado, J
2014-01-01
In this work, we study the radiative generation of the Lorentz-violating Euler-Heisenberg action, in the weak field approximation. For this, we first consider a nonperturbative calculation in the coefficient $c_{\\mu\
Soft symmetry improvement of two particle irreducible effective actions
Brown, Michael J.; Whittingham, Ian B.
2017-01-01
Two particle irreducible effective actions (2PIEAs) are valuable nonperturbative techniques in quantum field theory; however, finite truncations of them violate the Ward identities (WIs) of theories with spontaneously broken symmetries. The symmetry improvement (SI) method of Pilaftsis and Teresi attempts to overcome this by imposing the WIs as constraints on the solution; however, the method suffers from the nonexistence of solutions in linear response theory and in certain truncations in equilibrium. Motivated by this, we introduce a new method called soft-symmetry improvement (SSI) which relaxes the constraint. Violations of WIs are allowed but punished in a least-squares implementation of the symmetry improvement idea. A new parameter ξ controls the strength of the constraint. The method interpolates between the unimproved (ξ →∞ ) and SI (ξ →0 ) cases, and the hope is that practically useful solutions can be found for finite ξ . We study the SSI 2PIEA for a scalar O (N ) model in the Hartree-Fock approximation. We find that the method is IR sensitive; the system must be formulated in finite volume V and temperature T =β-1 , and the V β →∞ limit must be taken carefully. Three distinct limits exist. Two are equivalent to the unimproved 2PIEA and SI 2PIEA respectively, and the third is a new limit where the WI is satisfied but the phase transition is strongly first order and solutions can fail to exist depending on ξ . Further, these limits are disconnected from each other; there is no smooth way to interpolate from one to another. These results suggest that any potential advantages of SSI methods, and indeed any application of (S)SI methods out of equilibrium, must occur in finite volume.
Effects of navigated TMS on object and action naming
Directory of Open Access Journals (Sweden)
Julio Cesar Hernandez-Pavon
2014-09-01
Full Text Available Transcranial magnetic stimulation (TMS has been used to induce speech disturbances and to affect speech performance during different naming tasks. Lately, repetitive navigated TMS (nTMS has been used for non-invasive mapping of cortical speech-related areas. Different naming tasks may give different information that can be useful for presurgical evaluation. We studied the sensitivity of object and action naming tasks to nTMS and compared the distributions of cortical sites where nTMS produced naming errors. Eight healthy subjects named pictures of objects and actions during repetitive nTMS delivered to semi-random left-hemispheric sites. Subject-validated image stacks were obtained in the baseline naming of all pictures before nTMS. Thereafter, nTMS pulse trains were delivered while the subjects were naming the images of objects or actions. The sessions were video-recorded for offline analysis. Naming during nTMS was compared with the baseline performance. The nTMS-induced naming errors were categorized by error type and location. nTMS produced no-response errors, phonological paraphasias, and semantic paraphasias. In seven out of eight subjects, nTMS produced more errors during object than action naming. Both intrasubject and intersubject analysis showed that object naming was significantly more sensitive to nTMS. When the number of errors was compared according to a given area, nTMS to postcentral gyrus induced more errors during object than action naming. Object naming is apparently more easily disrupted by TMS than action naming. Different stimulus types can be useful for locating different aspects of speech functions. This provides new possibilities in both basic and clinical research of cortical speech representations.
Flavor symmetry breaking and scaling for improved staggered actions in quenched QCD
Cheng, M; Jung, C; Karsch, F; Mawhinney, R D; Petreczky, P; Petrov, K V
2006-01-01
We present a study of the flavor symmetry breaking in the pion spectrum for various improved staggered fermion actions. To study the effects of link fattening and tadpole improvement, we use three different variants of the p4 action - p4fat3, p4fat7, and p4fat7tad. These are compared to Asqtad and also to naive staggered. To study the pattern of symmetry breaking, we measure all 15 meson masses in the 4-flavor staggered theory. The measurements are done on a quenched gauge background, generated using a one-loop improved Symanzik action with $\\beta=10/g^2 = 7.40, 7.75,$ and 8.00, corresponding to lattice spacings of approximately a = .31 fm., .21 fm., and .14 fm. We also study how the lattice scale set by the $\\rho$ mass on each of these ensembles compares to one set by the static quark potential.
Sato, Atsushi; Itakura, Shoji
2013-01-01
In everyday social life, we predict others' actions in response to our own actions. Subsequently, on the basis of these predictions, we control our actions to attain desired social outcomes and/or adjust our actions to accommodate the anticipated actions of the others. Representation of the bidirectional association between our and others'…
Response selection difficulty modulates the behavioral impact of rapidly learnt action effects.
Directory of Open Access Journals (Sweden)
Uta eWolfensteller
2014-12-01
Full Text Available It is well established that we can pick up action effect associations when acting in a free-choice intentional mode. However, it is less clear whether and when action effect associations are learnt and actually affect behavior if we are acting in a forced-choice mode, applying a specific stimulus-response (S-R rule. In the present study, we investigated whether response selection difficulty imposed by S-R rules influences the initial rapid learning and the behavioral expression of previously learnt but weakly practiced action effect associations when those are re-activated by effect exposure. Experiment 1 showed that the rapid acquisition of action effect associations is not directly influenced by response selection difficulty. By contrast, the behavioral expression of re-activated action effect associations is prevented when actions are directly activated by highly over-learnt response cues and thus response selection difficulty is low. However, all three experiments showed that if response selection difficulty is sufficiently high during re-activation, the same action effect associations do influence behavior. Experiment 2 and 3 revealed that the effect of response selection difficulty cannot be fully reduced to giving action effects more time to prime an action, but seems to reflect competition during response selection. Finally, the present data suggest that when multiple novel rules are rapidly learnt in succession, which requires a lot of flexibility, action effect associations continue to influence behavior only if response selection difficulty is sufficiently high. Thus, response selection difficulty might modulate the impact of experiencing multiple learning episodes on action effect expression and learning, possibly via inducing different strategies.
The Geometry of Quantum Hall Effect: An Effective Action for all Dimensions
Karabali, Dimitra
2016-01-01
We present a general formula for the topological part of the effective action for quantum Hall systems in higher dimensions, including fluctuations of the gauge field and metric around background fields of a specified topological class. The result is based on a procedure of integrating up from the Dolbeault index density which applies for the degeneracies of Landau levels, combined with some input from the standard descent procedure for anomalies. Features of the topological action in (2+1), (4+1), (6+1) dimensions, including the contribution due to gravitational anomalies, are discussed in some detail.
Effects of context on visuomotor interference depends on the perspective of observed actions.
Directory of Open Access Journals (Sweden)
Marta Bortoletto
Full Text Available Visuomotor interference occurs when the execution of an action is facilitated by the concurrent observation of the same action and hindered by the concurrent observation of a different action. There is evidence that visuomotor interference can be modulated top-down by higher cognitive functions, depending on whether own performed actions or observed actions are selectively attended. Here, we studied whether these effects of cognitive context on visuomotor interference are also dependent on the point-of-view of the observed action. We employed a delayed go/no-go task known to induce visuomotor interference. Static images of hand gestures in either egocentric or allocentric perspective were presented as "go" stimuli after participants were pre-cued to prepare either a matching (congruent or non-matching (incongruent action. Participants performed this task in two different cognitive contexts: In one, they focused on the visual image of the hand gesture shown as the go stimulus (image context, whereas in the other they focused on the hand gesture they performed (action context. We analyzed reaction times to initiate the prepared action upon presentation of the gesture image and found evidence of visuomotor interference in both contexts and for both perspectives. Strikingly, results show that the effect of cognitive context on visuomotor interference also depends on the perspective of observed actions. When focusing on own-actions, visuomotor interference was significantly less for gesture images in allocentric perspective than in egocentric perspective; when focusing on observed actions, visuomotor interference was present regardless of the perspective of the gesture image. Overall these data suggest that visuomotor interference may be modulated by higher cognitive processes, so that when we are specifically attending to our own actions, images depicting others' actions (allocentric perspective have much less interference on our own actions.
Action Research in Professional Development Schools: Effects on Student Learning.
Devlin-Scherer, Wade; Spinelli, Ann Marie; Giammatteo, Dawn; Johnson, Craig; Mayo-Molina, Sylvia; McGinley, Paula; Michalski, Candice; Schmidek, Susan; Tomaiuolo, Linda; Zisk, Laurie
This report presents data from one elementary school's (Hartford, CT region) second year (1996-97) implementation of a mathematics reform action research project by the professional development team. Teachers from grades 2-5 systematically implemented an ancillary problem solving curriculum in their classrooms after receiving training by a…
Effects of arsenicals on interferon formation and action
Energy Technology Data Exchange (ETDEWEB)
Gainer, J.H.
1972-01-01
Interactions between arsenicals and interferon (IF) production and action are described. The protection afforded by poly I/poly C (PIC) against the death of mice from infection with the encephalomyocarditis virus (EMCV) was partially inhibited by sodium arsenite (NaAsO/sub 2/) and by roxarsone. Spleen of EMCV-exposed, NaAsO/sub 2/-treated mice contained 1 to 3 logs more virus than did spleen of saline solution-treated EMCV-exposed controls. A stimulating substance for the formation of plaques by the vesicular stomatitis virus (VSV) was present in spleen of the NaAsO/sub 2/-treated, EMCV-exposed mice. Detectable IF was not seen in spleen of NaAsO/sub 2/-treated, EMCV-exposed mice; low levels of IF were in spleen of EMCV-exposed control mice. Treatment of primary rabbit kidney (PRK) cell cultures with NaAsO/sub 2/ inhibited the induction of IF by PIC. In mouse embryo (ME) cells, NaAsO/sub 2/, sodium arsenate (Na/sub 2/HAsO/sub 4/), roxarsone, and p-arsanilic acid inhibited the action of mouse IF. The inhibition of IF action by the arsenicals was cell mediated and was time dependent, the inhibition by NaAsO/sub 2/ being ineffective before IF was added and 2 hours after IF was added, but being fully active at 0 and 1 hours after exposure of the cells to IF. The NaAsO/sub 2/ did not alter IF activity directly. A dose-response relationship occurred between the concentration of arsenical tested and the percentage of inhibition of IF action which ensued. Data presented have indicated that high concentrations of arsenicals inhibited both the synthesis and the action of IF, whereas low concentrations of arsenicals increased the antiviral activity of low levels of IF. 11 references, 5 figures, 2 tables.
2PI Effective Action and Evolution Equations of N = 4 super Yang-Mills
Smolic, Jelena
2011-01-01
We employ nPI effective action techniques to study N = 4 super Yang-Mills, and write down the 2PI effective action of the theory. We also supply the evolution equations of two-point correlators within the theory.
Kaiya, Hiroyuki; Kangawa, Kenji; Miyazato, Mikiya
2013-01-15
Ten years and more passed since ghrelin was discovered. Various physiological actions of ghrelin have been documented in both mammalian and nonmammalian vertebrates. Do these actions have any commonality? In this review, we focused on several effects of ghrelin, and compared the effect across vertebrates. We would like to discuss possible general function of ghrelin in vertebrates.
2PI effective action and evolution equations of N=4 super Yang-Mills
Energy Technology Data Exchange (ETDEWEB)
Smolic, Jelena; Smolic, Milena [University of Amsterdam, Institute for Theoretical Physics, Amsterdam (Netherlands)
2012-08-15
We employ nPI effective action techniques to study N=4 super Yang-Mills, and write down the 2PI effective action of the theory to two-loop order in the symmetric phase. We also supply the evolution equations of two-point correlators within the theory. (orig.)
Induced wormholes due to quantum effects of spherically reduced matter in large N approximation
Nojiri, S; Odintsov, S D; Osetrin, K E
1999-01-01
Using one-loop effective action in large N and s-wave approximation we discuss the possibility to induce primordial wormholes at the early Universe. An analytical solution is found for self-consistent primordial wormhole with constant radius. Numerical study gives the wormhole solution with increasing throat radius and red-shift function which first increases and then decreases. This may indicate the possibility of a topological phase transition.
Effective Lagrangian of SU（2） Yang—Mills Theory in the Presence of Fermions
Institute of Scientific and Technical Information of China (English)
FANJi－Yang; JIANGYing; 等
2002-01-01
We derive the one-loop effective action of SU(2) Yang-Mills theory in the presence of fermions in the low energy limit.This result is presented by separating the topological degrees,which describe the non-Abelian monopoles from the dynamical degrees of the gauge potential and integrate out all the dynamical degrees and fermions in SU(2) Yang-Mills theory.
Action semantics modulate action prediction.
Springer, Anne; Prinz, Wolfgang
2010-11-01
Previous studies have demonstrated that action prediction involves an internal action simulation that runs time-locked to the real action. The present study replicates and extends these findings by indicating a real-time simulation process (Graf et al., 2007), which can be differentiated from a similarity-based evaluation of internal action representations. Moreover, results showed that action semantics modulate action prediction accuracy. The semantic effect was specified by the processing of action verbs and concrete nouns (Experiment 1) and, more specifically, by the dynamics described by action verbs (Experiment 2) and the speed described by the verbs (e.g., "to catch" vs. "to grasp" vs. "to stretch"; Experiment 3). These results propose a linkage between action simulation and action semantics as two yet unrelated domains, a view that coincides with a recent notion of a close link between motor processes and the understanding of action language.
Making connections to translate climate research into effective action
Evans, K. J.; Niepold, F., III; Pierce, L.
2016-12-01
Climate change is strongly apparent at many scales and facets of the Earth system including glacier retreat, increased ocean acidity, altered meteorological patterns, and changing ecosystems. There is general recognition that a more strategic and coordinated response is needed to ameliorate these impacts on communities and to limit the global temperature increase to 1.5°C imposed by the 2015 Paris agreement. However, concrete plans to achieve these goals require actionable and specific guidance from the scientific community that is targeted for specific stakeholder groups within government agencies, industry, and individuals, while also supporting decision-makers plans and policies. This guidance depends on scientific advances that establish quantified predictions and minimize the levels of uncertainty. Although, these advances are ongoing; the decision maker, civil society organizations, and business and investor communities are not waiting for perfection. The urgency of taking action now has brought new approaches to the fore that try to bring the best available science into the business and decision making process. Combining a breadth of expertise, we highlight the specific transmission pathways of information needed for stakeholders, and it spans initial data collection and climate model construction, experimentation, analysis, synthesis of results, education, to government, communities, and business planning to reduce impacts and minimize additional human-caused contributions. We propose a multi-pathway relay along these paths. In one direction we encourage scientists to provide accessible and useable summary results with uncertainties to educators and stakeholders, who in turn need to collate results in a manner that enables interested parties to identify their specific mitigation action. In the other direction, stakeholders and shareholders are already requesting more comprehensive verification, validation, and active linkages to the way in which
Hlubek, M D; Cobbett, P
2000-09-15
Recordings were made from magnocellular neuroendocrine cells dissociated from the supraoptic nucleus of the adult guinea pig to determine the role of voltage gated K(+) channels in controlling the duration of action potentials and in mediating frequency-dependent action potential broadening exhibited by these neurons. The K(+) channel blockers charybdotoxin (ChTx), tetraethylammonium (TEA), and 4-aminopyridine (4-AP) increased the duration of individual action potentials indicating that multiple types of K(+) channel are important in controlling action potential duration. The effect of these K(+) channel blockers was almost completely reversed by simultaneous blockade of voltage gated Ca(2+) channels with Cd(2+). Frequency-dependent action potential broadening was exhibited by these neurons during trains of action potentials elicited by membrane depolarizing current pulses presented at 10 Hz but not at 1 Hz. 4-AP but not ChTx or TEA inhibited frequency-dependent action potential broadening indicating that frequency-dependent action potential broadening is dependent on increasing steady-state inactivation of A-type K(+) channels (which are blocked by 4-AP). A model of differential contributions of voltage gated K(+) channels and voltage gated Ca(2+) channels to frequency-dependent action potential broadening, in which an increase of Ca(2+) current during each successive action potential is permitted as a result of the increasing steady-state inactivation of A-type K(+) channels, is presented.
Explicit learning of arbitrary and non-arbitrary action-effect relations in adults and 4-year-olds
Stephan Alexander eVerschoor; Rena eEenshuistra; Jutta eKray; Szilvia eBiro; Bernhard eHommel
2012-01-01
Ideomotor theories claim that carrying out a movement that produces a perceivable effect creates a bidirectional association between the two, which can be used by action control processes to retrieve the associated action by anticipating its outcome. Indeed, previous implicit-learning studies have shown that practice renders novel but action-contingent stimuli effective retrieval cues of the action they used to follow, suggesting that experiencing sequences of actions and effects creates bidi...
Effective action for. omega. -> 3. pi. ,. omega. ->. pi gamma. and rho ->. pi gamma
Energy Technology Data Exchange (ETDEWEB)
Golterman, M.F.L.
1988-10-31
It is argued that the decay widths for ..omega.. -> 3..pi.., ..omega.. -> ..pi gamma.. and rho -> ..pi gamma.. do not follow from the gauged Wess-Zumino-Witten action. An alternative effective action for these decays is constructed and its parameters are fitted to the experimental values of the widths.
Effective action of composite fields for general gauge theories in BLT-covariant formalism
Lavrov, P M; Reshetnyak, A A
1996-01-01
The gauge dependence of the effective action of composite fields for general gauge theories in the framework of the quantization method by Batalin, Lavrov and Tyutin is studied. The corresponding Ward identites are obtained. The variation of composite fields effective action is found in terms of new set of generators depending on composite field. The theorem of the on-shell gauge fixing independence for the effective action of composite fields in such formalism is proven. Brief discussion of gravitational-vector induced interaction for Maxwell theory with composite fields is given.
Energy Technology Data Exchange (ETDEWEB)
Lavrov, P.M.; Odintsov, S.D. [Department of Mathematical Analysis, Tomsk State Pedagogical University, Tomsk 634041 (Russia)]|[Department ECM, Faculte de Fisica, Universidad de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Reshetnyak, A.A. [Quantum Field Theory Department, Tomsk State University, Tomsk 634050 (Russia)
1997-07-01
The gauge dependence of the effective action of composite fields for general gauge theories in the framework of the quantization method by Batalin, Lavrov and Tyutin is studied. The corresponding Ward identities are obtained. The variation of composite fields effective action is found in terms of new set of generators depending on composite field. The theorem of the on-shell gauge fixing independence for the effective action of composite fields in such formalism is proven. A brief discussion of gravitational-vector induced interaction for Maxwell theory with composite fields is given. {copyright} {ital 1997 American Institute of Physics.}
The effects of an action video game on visual and affective information processing.
Bailey, Kira; West, Robert
2013-04-04
Playing action video games can have beneficial effects on visuospatial cognition and negative effects on social information processing. However, these two effects have not been demonstrated in the same individuals in a single study. The current study used event-related brain potentials (ERPs) to examine the effects of playing an action or non-action video game on the processing of emotion in facial expression. The data revealed that 10h of playing an action or non-action video game had differential effects on the ERPs relative to a no-contact control group. Playing an action game resulted in two effects: one that reflected an increase in the amplitude of the ERPs following training over the right frontal and posterior regions that was similar for angry, happy, and neutral faces; and one that reflected a reduction in the allocation of attention to happy faces. In contrast, playing a non-action game resulted in changes in slow wave activity over the central-parietal and frontal regions that were greater for targets (i.e., angry and happy faces) than for non-targets (i.e., neutral faces). These data demonstrate that the contrasting effects of action video games on visuospatial and emotion processing occur in the same individuals following the same level of gaming experience. This observation leads to the suggestion that caution should be exercised when using action video games to modify visual processing, as this experience could also have unintended effects on emotion processing. Published by Elsevier B.V.
System markets: Indirect network effects in action, or inaction?
J.L.G. Binken (Jeroen)
2010-01-01
textabstractIn this dissertation, I empirically examine system markets up close. More specifically I examine indirect network effects, both demand-side and supply-side indirect network effects. Indirect network effects are the source of positive feedback in system markets, or so network effect
System markets: Indirect network effects in action, or inaction?
J.L.G. Binken (Jeroen)
2010-01-01
textabstractIn this dissertation, I empirically examine system markets up close. More specifically I examine indirect network effects, both demand-side and supply-side indirect network effects. Indirect network effects are the source of positive feedback in system markets, or so network effect theo
Nakanishi, H; Matsuoka, I; Ono, T; Yoshida, H; Uchibori, T; Kogi, K
1996-12-01
Effects of verapamil, prenylamine and a prenylamine analog, MG8926 on the intracellular spontaneous action potentials recorded from the isolated rabbit sinoatrial (SA) node were studied. Verapamil (1 microM), a selective inhibitor for slow Ca2+ channels, prolonged the cycle length, decreased the rate of diastolic depolarization, the rate of rise of action potential, the amplitude of action potential and the maximal diastolic potential, and usually arrested showing subthreshold fluctuation of the membrane potential within several ten min. Prenylamine (10 microM), a nonselective inhibitor for slow Ca2+ channels, tended to prolong the cycle length to decrease the diastolic depolarization, the rate of rise of action potential, the amplitude of action potential. However, these changes were statistically insignificant. Prenylamine at the concentration of 10 microM had no effect on the maximal diastolic potential. MG8926 (10 microM) prolonged the cycle length, decreased the rate of diastolic depolarization, the rate of rise of action potential and tended to decrease the amplitude of action potential. MG8926 at the concentration of 10 microM had almost no effect on the maximal diastolic potential. The present findings may indicate that replacement of phenyl residue of prenylamine by cyclohexyl residue increases the inhibitory action on the slow Ca2+ channels in rabbit SA node.
Action time effect of lime on its depressive ability for pyrite
Institute of Scientific and Technical Information of China (English)
Tichang Sun
2004-01-01
Two sample groups of bulk concentrates consisting mainly of pyrite and chalcopyrite from Daye and Chenghchao Mines in Hubei Province of China were used to investigate the effect of the action time of lime on its depressive ability for pyrite. The experimental results conducted with different samples and collectors showed that the action time between lime and pyrite markedly influences the depressive ability of lime. The depressive ability of lime increased with the action time increasing. It was also proved that the depressive results obtained at a large lime dosage after a shorter action time are similar to those obtained at a small lime dosage after a longer action time. The increase of depressive ability of lime after a longer action time is because that there are different mechanisms in different action time. The composition on the surface of pyrite acted for different time with lime was studied by using ESCA (Electron Spectroscopic Chemical Analysis). The results showed that iron hydroxide and calcium sulphate formed on the pyrite surface at the presence of lime in the pulp but the amounts of iron hydroxide and calcium sulphate were different at different action time. At the beginning action time the compound formed on the pyrite surface was mainly calcium sulphate and almost no iron hydroxide formed; but with the action time increasing, iron hydroxide formed. The longer the action time, the more iron hydroxide and the less calcium sulphate formed. It was considered that the stronger depressive ability of lime after a longer action time is because more iron hydroxide forms on the pyrite surface.
Leadership: Improving Its Effectiveness. Research Action Brief Number 1.
ERIC Clearinghouse on Educational Management, Eugene, OR.
This brief summarizes the major findings of significant research studies dealing with different leadership behaviors and strategies for increasing leadership effectiveness. Fred Fiedler's Contingency Theory of Leadership Effectiveness emphasizes that a leader's effectiveness is determined by how well his leadership style fits the specific…
Mechanism and Effectiveness of Reduction Action of Unsaturated Polyester Resin Reducer
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The reduction action mechanism of unsaturated polyester resin reducer is analysed.The experimental results show that the active reducer bearing reactive functional group on the ends of molecules effectively lowers the curing shrinkage of unvaturated polyester resin.
SUSY QCD effective action in the large N/sub c/ limit
Energy Technology Data Exchange (ETDEWEB)
Slavnov, A.A.; Chekhov, L.O.; Krivoshchekov, V.K.
1987-08-06
A low energy effective action for supersymmetric quantum chromodynamics (SUSY QCD) including anomalous terms is constructed in the leading order of the 1/N expansion. The absence of dynamical supersymmetry breaking is explicitly demonstrated.
The Spillover Effects of Affirmative Action on Competitiveness and Unethical Behavior
DEFF Research Database (Denmark)
Banerjee, Ritwik; Gupta, Nabanita Datta; Villeval, Marie Claire
We conduct an artefactual field experiment to examine various spillover effects of Affirmative Action policies in the context of castes in India. We test a) if individuals who compete in the presence of Affirmative Action policies remain competitive in the same proportion after the policy has been...... frequently a tournament payment scheme. However, we find no spillover effect on confidence and competitiveness once Affirmative Action is withdrawn: any lower caste’s gain in competitiveness due to the policy is then entirely wiped out. Furthermore, the strong existing bias of the dominant caste against...
Effect of Action Verbs on the Performance of a Complex Movement
Rabahi, Tahar; Fargier, Patrick; Rifai Sarraj, Ahmad; Clouzeau, Cyril; Massarelli, Raphael
2013-01-01
The interaction between language and motor action has been approached by studying the effect of action verbs, kinaesthetic imagery and mental subtraction upon the performance of a complex movement, the squat vertical jump (SVJ). The time of flight gave the value of the height of the SVJ and was measured with an Optojump® and a Myotest® apparatuses. The results obtained by the effects of the cognitive stimuli showed a statistically significant improvement of the SVJ performance after either loudly or silently pronouncing, hearing or reading the verb saute (jump in French language). Action verbs specific for other motor actions (pince = pinch, lèche = lick) or non-specific (bouge = move) showed no or little effect. A meaningless verb for the French subjects (tiáo = jump in Chinese) showed no effect as did rêve (dream), tombe (fall) and stop. The verb gagne (win) improved significantly the SVJ height, as did its antonym perds (lose) suggesting a possible influence of affects in the subjects’ performance. The effect of the specific action verb jump upon the heights of SVJ was similar to that obtained after kinaesthetic imagery and after mental subtraction of two digits numbers from three digits ones; possibly, in the latter, because of the intervention of language in calculus. It appears that the effects of the specific action verb jump did seem effective but not totally exclusive for the enhancement of the SVJ performance. The results imply an interaction among language and motor brain areas in the performance of a complex movement resulting in a clear specificity of the corresponding action verb. The effect upon performance may probably be influenced by the subjects’ intention, increased attention and emotion produced by cognitive stimuli among which action verbs. PMID:23844233
Effect of action verbs on the performance of a complex movement.
Directory of Open Access Journals (Sweden)
Tahar Rabahi
Full Text Available The interaction between language and motor action has been approached by studying the effect of action verbs, kinaesthetic imagery and mental subtraction upon the performance of a complex movement, the squat vertical jump (SVJ. The time of flight gave the value of the height of the SVJ and was measured with an Optojump® and a Myotest® apparatuses. The results obtained by the effects of the cognitive stimuli showed a statistically significant improvement of the SVJ performance after either loudly or silently pronouncing, hearing or reading the verb saute (jump in French language. Action verbs specific for other motor actions (pince = pinch, lèche = lick or non-specific (bouge = move showed no or little effect. A meaningless verb for the French subjects (tiáo = jump in Chinese showed no effect as did rêve (dream, tombe (fall and stop. The verb gagne (win improved significantly the SVJ height, as did its antonym perds (lose suggesting a possible influence of affects in the subjects' performance. The effect of the specific action verb jump upon the heights of SVJ was similar to that obtained after kinaesthetic imagery and after mental subtraction of two digits numbers from three digits ones; possibly, in the latter, because of the intervention of language in calculus. It appears that the effects of the specific action verb jump did seem effective but not totally exclusive for the enhancement of the SVJ performance. The results imply an interaction among language and motor brain areas in the performance of a complex movement resulting in a clear specificity of the corresponding action verb. The effect upon performance may probably be influenced by the subjects' intention, increased attention and emotion produced by cognitive stimuli among which action verbs.
The Quantum Consistency of the Ten-Dimensional Heterotic String Effective Action
Institute of Scientific and Technical Information of China (English)
Simon Davis
2011-01-01
The finiteness of superstring theory at each order in perturbation theory is considered with respect to the ten-dimensional effective action. The quantum consistency of the ten-dimensional superstring effective action is confirmed with an analysis of the perturbative expansion of the quartic sector. It is found to be compatible with the finiteness of reduced four-dimensional theory. Furthermore, implications for the validity of superstring perturbation theory at lower energies is considered.
The effect of action recognition and robot awareness in cooperative robot teams
Energy Technology Data Exchange (ETDEWEB)
Parker, L.E.
1995-03-01
Previous research in cooperative robotics has investigated several possible ways of coordinating the actions of cooperative teams -- from implicit cooperation through sensory feedback to explicit cooperation using the exchange of communicated messages. These various approaches differ in the extent to which robot team members arc aware of, or recognize, the actions of their teammates, and the extent to which they use this information to effect their own actions. The research described in this paper investigates this issue of robot awareness of team member actions and its effect on cooperative team performance by examining the results of a series of experiments on teams of physical mobile robots performing a laboratory version of hazardous waste cleanup. In these experiments. we vary the team size (and thus the level of redundancy in team member capabilities) and the level of awareness robots have of their teammates` current actions and evaluate the team`s performance using two metrics: time and energy. The results indicate that the impact of action awareness on cooperative team performance is a function not only of team size and the metric of evaluation. but also on the degree to which the effects of actions can be sensed through the world, the relative amount of work that is available per robot, and the cost of replicated actions. From these empirical studies, we propose a number of principles regarding the use of action recognition and robot awareness of team member actions in cooperative teams -- principles which will help guide engineers in the design and composition of the proper cooperative team for a given robotic mission.
The effect of viewing graspable objects and actions in Parkinson's disease.
Poliakoff, Ellen; Galpin, Adam; Dick, Jeremy; Moore, Peter; Tipper, Steven P
2007-03-26
Viewing action-relevant stimuli such as a graspable object or another person moving can affect the observer's own motor system. Evidence exists that external stimuli may facilitate or hinder movement in Parkinson's disease, so we investigated whether action-relevant stimuli would exert a stronger influence. We measured the effect of action-relevant stimuli (graspable door handles and finger movements) on reaction times compared with baseline stimuli (bars and object movements). Parkinson's patients were influenced by the location of the baseline stimuli, but unlike healthy controls, action-relevant stimuli did not exert a stronger influence. This suggests that external cues exert their influence in Parkinson's disease through lower-level visual processes and the influence of action-relevant stimuli on the motor system is disrupted.
Spontaneously Broken Asymptotic Symmetries and an Effective Action for Horizon Dynamics
Eling, Christopher
2016-01-01
Asymptotic spacetime symmetries have been conjectured to play an important role in quantum gravity. In this paper we study the breaking of asymptotic symmetries associated with a null horizon boundary. In two-dimensions, these symmetries are reparametrizations of the time parameter on the horizon. We show how this horizon reparametrization symmetry is explicitly and spontaneously broken in dilaton gravity and construct an effective action for these pseudo-Goldstone modes using the on-shell gravitational action for a null boundary. The variation of this action yields the horizon constraint equation. This action is invariant under a 2 parameter subgroup of $SL(2)$ transformations, whose Noether charges we interpret via the membrane paradigm. We place these results in the context of recent work on the near $AdS_2$/ near $CFT_1$ correspondence. In this setting the horizon action characterizes the infrared regime near the horizon and has a hydrodynamical sigma model form. We also discuss our construction in Genera...
RG flows in d dimensions, the dilaton effective action, and the a-theorem
Elvang, Henriette
2012-01-01
Motivated by the recent dilaton-based proof of the 4d a-theorem, we study the dilaton effective action for RG flows in d dimensions. When d is even, the action consists of a Wess-Zumino (WZ) term, whose Weyl-variation encodes the trace-anomaly, plus all Weyl-invariants. For d odd, the action consists of Weyl-invariants only. We present explicit results for the flat-space limit of the dilaton effective action in d-dimensions up to and including 8-derivative terms. GJMS-operators from conformal geometry motivate a form of the action that unifies the Weyl-invariants and anomaly-terms into a compact general-d structure. A new feature in 8d is the presence of an 8-derivative Weyl-invariant that pollutes the O(p^8)-contribution from the WZ action to the dilaton scattering amplitudes; this may challenge a dilaton-based proof of an a-theorem in 8d. We use the example of a free massive scalar for two purposes: 1) it allows us to confirm the structure of the d-dimensional dilaton effective action explicitly; we carry o...
Adiponectin action: a combination of endocrine and autocrine/paracrine effects
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Gary eSweeney
2011-11-01
Full Text Available The widespread physiological actions of adiponectin have now been well characterized as clinical studies and work in animal models have established strong correlations between circulating adiponectin levels and various disease-related outcomes. Thus, conventional thinking attributes many of adiponectins beneficial effects to endocrine actions of adipose-derived adiponectin. However, it is now clear that several tissues can themselves produce adiponectin and there is growing evidence that locally produced adiponectin can mediate functionally important autocrine or paracrine effects. In this review article we discuss regulation of adiponectin production, its mechanism of action via receptor isoforms and signaling pathways and its principal physiological effects (ie. metabolic and cardiovascular. The role of endocrine actions of adiponectin and changes in local production of adiponectin or its receptors in whole body physiology is discussed.
World-volume effective action of exotic five-brane in M-theory
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Kimura, Tetsuji [Research and Education Center for Natural Sciences, Keio University, Hiyoshi 4-1-1, Yokohama, Kanagawa 223-8521 (Japan); Department of Physics, Tokyo Institute of Technology,Tokyo 152-8551 (Japan); Sasaki, Shin [Department of Physics, Kitasato University,Sagamihara 252-0373 (Japan); Yata, Masaya [Department of Physics, National University of Singapore,2, Science Drive 3, Singapore 117542 (Singapore)
2016-02-25
We study the world-volume effective action of an exotic five-brane, known as the M-theory 5{sup 3}-brane (M5{sup 3}-brane) in eleven dimensions. The supermultiplet of the world-volume theory is the N=(2,0) tensor multiplet in six dimensions. The world-volume action contains three Killing vectors k̂{sub Î}{sup M} (Î=1,2,3) associated with the U(1){sup 3} isometry. We find the effective T-duality rule for the eleven-dimensional backgrounds that transforms the M5-brane effective action to that of the M5{sup 3}-brane. We also show that our action provides the source term for the M5{sup 3}-brane geometry in eleven-dimensional supergravity.
World-volume Effective Action of Exotic Five-brane in M-theory
Kimura, Tetsuji; Yata, Masaya
2016-01-01
We study the world-volume effective action of an exotic five-brane, known as the M-theory $5^3$-brane (M$5^3$-brane) in eleven dimensions. The supermultiplet of the world-volume theory is the $\\mathcal{N} = (2, 0)$ tensor multiplet in six dimensions. The world-volume action contains three Killing vectors $\\hat{k}_{\\hat{I}} {}^M \\ (\\hat{I} =1,2,3)$ associated with the $U(1)^3$ isometry. We find the effective T-duality rule for the eleven-dimensional backgrounds that transforms the M5-brane effective action to that of the M$5^3$-brane. We also show that our action provides the source term for the M$5^3$-brane geometry in eleven-dimensional supergravity
Renormalization-group flow of the effective action of cosmological large-scale structures
Floerchinger, Stefan
2017-01-01
Following an approach of Matarrese and Pietroni, we derive the functional renormalization group (RG) flow of the effective action of cosmological large-scale structures. Perturbative solutions of this RG flow equation are shown to be consistent with standard cosmological perturbation theory. Non-perturbative approximate solutions can be obtained by truncating the a priori infinite set of possible effective actions to a finite subspace. Using for the truncated effective action a form dictated by dissipative fluid dynamics, we derive RG flow equations for the scale dependence of the effective viscosity and sound velocity of non-interacting dark matter, and we solve them numerically. Physically, the effective viscosity and sound velocity account for the interactions of long-wavelength fluctuations with the spectrum of smaller-scale perturbations. We find that the RG flow exhibits an attractor behaviour in the IR that significantly reduces the dependence of the effective viscosity and sound velocity on the input ...
[The effect of food intake on drug action].
Pletscher, W; Peretti, E
1990-01-01
Interactions between medicaments and food are only incompletely documented--despite their frequent occurrence. Food can influence the effect of medicaments in a variety of ways: the effect of the medicament can be delayed or weakened; in some cases the effect may also be increased. The interactions between the kinetics of medicaments and food are described in the present survey. The absorption conditions in the stomach and small intestine are influenced physiologically and chemically by food. In very rare cases the elimination of active ingredients too can be modified by the quality and quantity of the food. Detailed knowledge about the physical-chemical properties of the medicaments used help to optimize the pharmacotherapy in the individual case. For the patient, the easiest suggestion to follow would be to take the medicaments with plenty of water and always at the same time.
Acute Stressor Effects on Goal-Directed Action in Rats
Braun, Stephanie; Hauber, Wolfgang
2013-01-01
Here we examined effects of acute stressors that involve either systemic coadministration of corticosterone/yohimbine (3 mg/kg each) to increase glucocorticoid/noradrenaline activity (denoted as "pharmacological" stressor) or one or several distinct restraint stressors (denoted as "single" vs. "multiple" stressor) on…
Acute Stressor Effects on Goal-Directed Action in Rats
Braun, Stephanie; Hauber, Wolfgang
2013-01-01
Here we examined effects of acute stressors that involve either systemic coadministration of corticosterone/yohimbine (3 mg/kg each) to increase glucocorticoid/noradrenaline activity (denoted as "pharmacological" stressor) or one or several distinct restraint stressors (denoted as "single" vs. "multiple" stressor) on…
Antioxidative actions of statins: potential mechanisms for antiathersclerotic effects.
Watanabe, Takanori; Yasunari, Kenichi; Nakamura, Munehoro
2006-05-01
Inhibitors of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase (statins) are widely used for the prevention of atherosclerotic diseases. The effects of statins on the generation of reactive oxygen species (ROS) by in vitro and in vivo were studied. Administration of statins significantly decreased ROS generation in vitro and in vivo.
Actions of Ethanol on Voltage-Sensitive Sodium Channels: Effects on Neurotoxin Binding
1987-01-01
sodium inhibitory effect of ethanol on channel - mediated sodium influx channels ...Exprnmantal Trherpeutics Ped in I.SA. Actions of Ethanol on Voltage-Sensitive Sodium Channels : Effects on Neurotoxin Binding1 MICHAEL J. MULLIN 2 and... sodium channels . This indirect allosteric mechanism for inhibition of [H]BTX-B binding. effect orethanol was concentration-dependent and was
The potential of the effective Polyakov line action from the underlying lattice gauge theory
Greensite, Jeff
2012-01-01
I adapt a numerical method, previously applied to investigate the Yang-Mills vacuum wavefunctional, to the problem of extracting the effective Polyakov line action from SU(N) lattice gauge theories, with or without matter fields. The method can be used to find the variation of the effective Polyakov line action along any trajectory in field configuration space; this information is sufficient to determine the potential term in the action, and strongly constrains the possible form of the kinetic term. The technique is illustrated for both pure and gauge-Higgs SU(2) lattice gauge theory at finite temperature. A surprise, in the pure gauge theory, is that the potential of the corresponding Polyakov line action contains a non-analytic (yet center-symmetric) term proportional to |P|^3, where P is the trace of the Polyakov line at a given point, in addition to the expected analytic terms proportional to even powers of P.
Paulus, Markus; Hunnius, Sabine; Bekkering, Harold
2013-10-01
Social transmission of knowledge is one of the reasons for human evolutionary success, and it has been suggested that already human infants possess eminent social learning abilities. However, nothing is known about the neurocognitive mechanisms that subserve infants' acquisition of novel action knowledge through the observation of other people's actions and their consequences in the physical world. In an electroencephalogram study on social learning in infancy, we demonstrate that 9-month-old infants represent the environmental effects of others' actions in their own motor system, although they never achieved these effects themselves before. The results provide first insights into the neurocognitive basis of human infants' unique ability for social learning of novel action knowledge.
Effective actions, boundaries, and precision calculations of Casimir energies
Aghababaie, Y.; Burgess, C. P.
2004-10-01
We perform the matching required to compute the leading effective boundary contribution to the QED Lagrangian in the presence of a conducting surface, once the electron is integrated out. Our result resolves a confusion in the literature concerning the interpretation of the leading such correction to the Casimir energy. It also provides a useful theoretical laboratory for brane-world calculations in which kinetic terms are generated on the brane, since a lot is known about QED near boundaries.
The anomaly-induced effective action and natural inflation
Pelinson, A M; Solà, J; Takakura, F I
2003-01-01
The anomaly-induced inflation (modified Starobinsky model) is based on the application of the effective quantum field theory approach to the Early Universe. We present a brief general review of the model and show that it does not require a fine-tuning for the parameters of the theory or initial data, gives a real chance to meet a graceful exit to the FRW phase and also has positive features with respect to the metric perturbations.
Estimation of Several Political Action Effects of Energy Prices
Whitford, Andrew B
2015-01-01
One important effect of price shocks in the United States has been increased political attention paid to the structure and performance of oil and natural gas markets, along with some governmental support for energy conservation. This paper describes how price changes helped lead the emergence of a political agenda accompanied by several interventions, as revealed through Granger causality tests on change in the legislative agenda.
Action-effect binding is decreased in motor conversion disorder: implications for sense of agency.
Kranick, Sarah M; Moore, James W; Yusuf, Nadia; Martinez, Valeria T; LaFaver, Kathrin; Edwards, Mark J; Mehta, Arpan R; Collins, Phoebe; Harrison, Neil A; Haggard, Patrick; Hallett, Mark; Voon, Valerie
2013-07-01
The abnormal movements seen in motor conversion disorder are affected by distraction and entrainment, similar to voluntary movement. Unlike voluntary movement, however, patients lack a sense of control for the abnormal movements, a failure of "self-agency." The action-effect binding paradigm has been used to quantify the sense of self-agency, because subjective contraction of time between an action and its effect only occurs if the patient feels that they are the agent responsible for the action. We used this paradigm, coupled with emotional stimuli, to investigate the sense of agency with voluntary movements in patients with motor conversion disorder. Twenty patients with motor conversion disorder and 20 age-matched and sex-matched healthy volunteers used a rotating clock to judge the time of their own voluntary key presses (action) and a subsequent auditory tone (effect) after they completed conditioning blocks in which high, medium, and low tones were coupled to images of happy, fearful, and neutral faces. The results replicated those produced previously: it was reported that an effect after a voluntary action occurred earlier, and the preceding action occurred later, compared with trials that used only key presses or tones. Patients had reduced overall binding scores relative to healthy volunteers, suggesting a reduced sense of agency. There was no effect of the emotional stimuli (faces) or other interaction effects. Healthy volunteers with subclinical depressive symptoms had higher overall binding scores. We demonstrate that patients with motor conversion disorder have decreased action-effect binding for normal voluntary movements compared with healthy volunteers, consistent with the greater experience of lack of control. Copyright © 2013 Movement Disorder Society.
Low-energy effective action in N = 2 supersymmetric field theories
Bukhbinder, E I; Bukhbinder, I L; Ivanov, E A; Kuzenko, S M
2001-01-01
Review of new approach to finding effective action in N = 2 and N = 4 supersymmetric theory is given. The approach is based on the formulation of these theories in terms of unconstrained superfields in harmonic superspace. Construction of superfield model of N = 2 supersymmetric field theory (hypermultiplet, N = 2 supersymmetric Yang-Mills theory) is discussed. N = 2 background field method is considered. Perturbative holomorphic effective potential in N = 2 models and non-holomorphic effective potential in N = 4 Yang-Mills field theory, defining exact low-energy effective action in this theory, are studied. Possible applications of low-energy effective action in supersymmetric theories and some open problems are discussed. Comparison of given approach with others is performed
Effects of policosanol on gastroprotective action of D-002
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Daisy Carbajal Quintana
Full Text Available Introduction: policosanol, a mixture of higher aliphatic alcohols purified from sugar cane wax, is used to treat hypercholesterolemia. D-002 (Abexol, a mixture of higher aliphatic alcohols from beeswax, is an antioxidant supplement with gastroprotective effects. Then, concomitant intake of D-002 and policosanol may occur in routine practice, so potential pharmacological interactions between them should be researched on. Objective: to find out the influence of policosanol on the gastroprotective effect of D-002 on the ethanol-induced gastric ulcer model. Methods: rats were randomized into eight groups: one treated with the vehicle (control, two with D-002 (25 and 200 mg/kg, two with policosanol (25 and 200 mg/kg, two with the same doses of D-002 + policosanol and other with sucralfate (100 mg/kg. Treatments were given as single oral doses. One hour after treatment, rats received 60% ethanol orally and one hour later they were killed and their stomachs exposed. Effects on ulcer indexes (UI were assessed. Results: acute oral administration of D-002 (25 and 200 mg/kg significantly reduced the ulcer indexes by 40 % and 68 %, respectively, as compared to the control group, and policosanol by 26 % and 47 %, respectively. The concomitant administration of the same doses of D-002 and policosanol significantly decreased ulcer indexes by 64 % (both given at 25 mg/kg and by 92 % (both given at 200 mg/kg as compared to the respective monotherapies. Sucralfate (100 mg/kg significantly reduced (@ 99 % ulcer indexes compared to the control group. Conclusions: the concomitant oral administration of policosanol with D-00 2 gives greater gastroprotection than D-002 monotherapy, so both products can be taken together.
Evolution of the violin: The law of effect in action.
Wasserman, Edward A; Cullen, Patrick
2016-01-01
As is true for most other human inventions, the origin of the violin is unknown. What is known is that this popular and versatile instrument has notably changed over the course of several hundred years. At issue is whether those evolutionary changes in the construction of the violin are the result of premeditated, intelligent design or whether they arose through a trial-and-error process. Recent scientific evidence favors the latter account. Our perspective piece puts these recent empirical findings into a comprehensive selectionist framework. According to this view, the many things we do and make--like violins--arise from a process of variation and selection which accords with the law of effect. Contrary to popular opinion, there is neither mystique nor romance in this process; it is as fundamental and ubiquitous as the law of natural selection. As with the law of natural selection in the evolution of organisms, there is staunch resistance to the role of the law of effect in the evolution of human inventions. We conclude our piece by considering several objections to our perspective.
The effects of action observation training and mirror therapy on gait and balance in stroke patients
Lee, Ho Jeong; Kim, Young Mi; Lee, Dong Kyu
2017-01-01
[Purpose] The aim of this study was to evaluate the effects of action observation training and mirror therapy to improve on balance and gait function of stroke patients. [Subjects and Methods] The participants were randomly allocated to one of three groups: The action observation training with activity group practiced additional action observation training with activity for three 30-minute session for six weeks (n=12). The mirror therapy with activity group practiced additional mirror therapy with activity for three 30-minute sessions for six weeks (n=11). The only action observation training group practiced additional action observation training for three 30-minute sessions for weeks (n=12). All groups received conventional therapy for five 60-minute sessions over a six-week period. [Results] There were significant improvements in balance and gait function. The action observation training with activity group significantly improved subjects’ static balance. The action observation training with activity group and the mirror therapy with activity group significantly improved subjects’ gait ability. [Conclusion] The activation of mirror neurons combined with a conventional stroke physiotherapy program enhances lower-extremity motor recovery and motor functioning in stroke patients. PMID:28356646