In this work, we explore a mechanism for abelian gauge field localization on thick branes based five-dimensional Stueckelberg-like action. A normalizable zero mode is found through the identification of suitable coupling function between brane and field. The same studied Kalb–Ramond

Extending work by Gies and Karbstein on the Euler-Heisenberg Lagrangian, it has recently been shown that one-loop propagator of a charged scalar particle in constant electromagnetic field one-particle reducible contribution addition to well-studied irreducible one. Here we further generalize this result spinor case, find same relation between term, tree-level Lagrangian as case. Our demonstration uses novel worldline path integral representation photon-dressed background.

We study the propagator of a colored scalar particle in background non-Abelian gauge field using worldline formalism. It is obtained by considering open with extra degrees freedom needed to take into account color charge particle, which we choose be fundamental representation group. Specializing external given sum plane waves, i.e. gluons, produce master formula for an arbitrary number gluons directly attached line, akin similar formulas derived literature case performing loop. Our...

In the first-quantised worldline approach to quantum field theory, a long-standing problem has been extend this formalism amplitudes involving open fermion lines while maintaining efficiency of well-tested closed-loop case. present series papers, we develop suitable for case electrodynamics in vacuum (part one and two) constant external electromagnetic three), based on second-order fermions symbol map. We derive from standard but also give an alternative derivation intrinsic theory. first...

We generalize the worldline formalism to include spin 1/2 fields coupled gravity. To this purpose we first extend dimensional regularization supersymmetric nonlinear sigma models in one dimension. consider a finite propagation time and find that is manifestly scheme, since classically action does not need any counterterm preserve supersymmetry. apply scheme description of Dirac fermions compute trace anomaly fermion 4 dimensions, providing an additional check on with time. Then come main...

A bstract In the first part of this series, we employed second-order formalism and “symbol” map to construct a particle path-integral representation electron propagator in background electromagnetic field, suitable for open fermion-line calculations. Its main advantages are avoidance long products Dirac matrices, its ability unify whole sets Feynman diagrams related by permutation photon legs along fermion lines. We obtained Bern-Kosower type master formula propagator, dressed with N...

We explore models of intersecting brane worlds with induced gravity terms on codimension-one branes and their intersection. Maximally symmetric solutions for the intersection are found. find new self-accelerating solutions. In a 6D spacetime, realize seesaw modification where UV scale to 4D is determined by Planck given ${M}_{6}\ensuremath{\sim}{10}^{\ensuremath{-}3}\text{ }\text{ }\mathrm{eV}$ IR ${M}_{6}^{2}/{M}_{4}\ensuremath{\sim}{H}_{0}\ensuremath{\sim}{10}^{\ensuremath{-}42}\text{...

We explore cosmology of intersecting brane worlds with induced gravity on the branes. find cosmological equations that control evolution a moving codimension-one and codimension-two sits at intersection. study Friedmann equation intersection, finding new contributions from six-dimensional bulk. These higher dimensional allow us to examples self-accelerating configurations for intersection we discuss their features.

The study of the heat-trace expansion in noncommutative field theory has shown existence Moyal nonlocal Seeley-DeWitt coefficients which are related to UV/IR mixing and manifest, some cases, non-renormalizability theory.We show that these models can be studied a worldline approach implemented phase space arrive at master formula for n-point contribution expansion.This formulation could useful understanding open problems this area, as torus or introduction renormalizing terms action, well...

The worldline formalism has previously been used for deriving compact master formulas the one-loop N-photon amplitudes in both scalar and spinor QED, vacuum as well a constant external field. For there is also an analogous formula propagator dressed with N photons vacuum. Here, we extend this to include two-photon case worked out explicitly, yielding integral representation Compton scattering cross section field suitable numerical integration full range of electric magnetic strengths.

Using cluster perturbation theory we calculate Green's functions, quasi-particle energies and topological invariants for interacting electrons on a 2D honeycomb lattice, with intrinsic spin–orbit coupling on-site e–e interaction. This allows us to define the parameter range (Hubbard U versus coupling) where system behaves as trivial insulator or quantum spin Hall insulator. behavior is confirmed by existence of gapless states in ribbons. We have discussed importance symmetry effects lack...

The relation for the gravity polarisation tensor as product of two gluon vectors has been well-known a long time, but version this multi-particle fields is presently still not known. Here we show that in order to happen first have ensure polarisations satisfy colour-kinematics duality. In previous work it arises naturally from Bern-Kosower formalism one-loop amplitudes, and here arise Bern-Dunbar-Shimada amplitudes. This allows us formulate new prescription double-copy Berends-Giele...

We present first results of a systematic study the structure low energy limit one-loop photon-graviton amplitudes induced by massive scalars and spinors. Our main objective is search KLT-type relations where effectively two photons merge into graviton. find such relation at graviton-photon-photon level. also derive diffeomorphism Ward identity for 1PI one graviton - N photon amplitudes.

We study the combined effects of lattice deformation, $e\text{\ensuremath{-}}e$ interaction, and spin-orbit coupling in a two-dimensional (2D) honeycomb lattice. adopt different kinds hopping modulation---generalized dimerization Kekul\'e distortion---and calculate topological invariants for noninteracting system interacting system. identify parameter range (Hubbard $U$, modulation, coupling) where 2D behaves as trivial insulator or quantum spin Hall insulator.

We consider the first quantised approach to quantum field theory coupled a non-Abelian gauge field. Representing colour degrees of freedom with single family auxiliary variables matter transforms in reducible representation group which — by adding suitable Chern-Simons term particle action can be projected onto chosen fully (anti-)symmetric representation. By considering F families variables, we describe how extend model arbitrary tensor products representations, realises U(F ) "flavour"...