Asymptotic symmetries at null-infinity for the Rarita-Schwinger field with magnetic term

In this paper we study the magnetic charges of the free massless Rarita-Schwinger field in four dimensional asymptotically flat space-time. This is the first step towards extending the study of the dual BMS charges to supergravity. The magnetic charges appear due to the addition of a boundary term in the action. This term is similar to the theta term in Yang-Mills theory. At null-infinity an infinite dimensional algebra is discovered, both for the electric and magnetic charge.

Boundary electromagnetic duality from homological edge modes

Recent years have seen a renewed interest in using ‘edge modes’ to extend the pre-symplectic structure of gauge theory on manifolds with boundaries. Here we further the investigation undertaken in [1] by using the formalism of homotopy pullback and Deligne- Beilinson cohomology to describe an electromagnetic (EM) duality on the boundary of M = B3 × ℝ. Upon breaking a generalized global symmetry, the duality is implemented by a BF-like topological boundary term. We then introduce Wilson line singularities on ∂M and show that these induce the existence of dual edge modes, which we identify as connections over a (−1)-gerbe. We derive the pre-symplectic structure that yields the central charge in [1] and show that the central charge is related to a non-trivial class of the (−1)-gerbe.

Extended General Relativity for a Conformally Curved Universe

The recent Planck Legacy release confirmed the presence of an enhanced lensing amplitude in the cosmic microwave background (CMB) power spectra. Notably, this amplitude is higher than that estimated by the lambda cold dark matter model (ΛCDM), which endorses a positively curved early Universe with a confidence level greater than 99%. Although General Relativity (GR) performs accurately in the local/present Universe where spacetime is almost flat, its lost boundary term, incompatibility with Quantum Mechanics and the necessity of dark matter/energy could indicate its incompleteness. By utilising the Einstein–Hilbert action, this letter presents extended field equations by considering the pre-existing/background curvature and the boundary contribution. The extended field equations consist of Einstein field equations with a conformal transformation feature in addition to the boundary term, which can remove singularities, satisfy a conformal invariance theory and facilitate its quantisation.

Revisiting the flux tube spectrum of 3d SU(2) lattice gauge theory

We perform a high-precision measurement of the spectrum of the flux tube in three-dimensional $${\text {SU}}(2)$$ SU ( 2 ) gauge theory at multiple lattice spacings. We compare the results at large $$q\bar{q}$$ q q ¯ separations R to the spectrum predicted by the effective string theory, including the leading-order boundary term with a nonuniversal coefficient. We find qualitative agreement with the predictions from the leading-order Nambu–Goto string theory down to small values of R, while, at the same time, observing the predicted splitting of the second excited state due to the boundary term. On fine lattices and at large R, we observe slight deviations from the EST predictions for the first excited state.

The Wilson-loop d log representation for Feynman integrals

We introduce and study a so-called Wilson-loop d log representation of certain Feynman integrals for scattering amplitudes in $$ \mathcal{N} $$ N = 4 SYM and beyond, which makes their evaluation completely straightforward. Such a representation was motivated by the dual Wilson loop picture, and it can also be derived by partial Feynman parametrization of loop integrals. We first introduce it for the simplest one-loop examples, the chiral pentagon in four dimensions and the three-mass-easy hexagon in six dimensions, which are represented by two- and three-fold d log integrals that are nicely related to each other. For multi-loop examples, we write the L-loop generalized penta-ladders as 2(L − 1)-fold d log integrals of some one-loop integral, so that once the latter is known, the integration can be performed in a systematic way. In particular, we write the eight-point penta-ladder as a 2L-fold d log integral whose symbol can be computed without performing any integration; we also obtain the last entries and the symbol alphabet of these integrals. Similarly we study the symbol of the seven-point double-penta-ladder, which is represented by a 2(L − 1)-fold integral of a hexagon; the latter can be written as a two-fold d log integral plus a boundary term. We comment on the relation of our representation to differential equations and resumming the ladders by solving certain integral equations.

Dirac’s Formalism for Time-Dependent Hamiltonian Systems in the Extended Phase Space

Dirac’s formalism for constrained systems is applied to the analysis of time-dependent Hamiltonians in the extended phase space. We show that the Lewis invariant is a reparametrization invariant, and we calculate the Feynman propagator using the extended phase space description. We show that the Feynman propagator’s quantum phase is given by the boundary term of the canonical transformation of the extended phase space. We propose a new canonical transformation within the extended phase space that leads to a Lewis invariant generalization, and we sketch some possible applications.

Fermion localization in braneworld teleparallel f(T, B) gravity

We study a spin 1/2 fermion in a thick braneworld in the context of teleparallel f(T, B) gravity. Here, f(T, B) is such that $$f_1(T,B)=T+k_1B^{n_1}$$ f 1 ( T , B ) = T + k 1 B n 1 and $$f_2(T,B)=B+k_2T^{n_2}$$ f 2 ( T , B ) = B + k 2 T n 2 , where $$n_{1,2}$$ n 1 , 2 and $$k_{1,2}$$ k 1 , 2 are parameters that control the influence of torsion and the boundary term. We assume Yukawa coupling, where one scalar field is coupled to a Dirac spinor field. We show how the $$n_{1,2}$$ n 1 , 2 and $$k_{1,2}$$ k 1 , 2 parameters control the width of the massless Kaluza–Klein mode, the breadth of non-normalized massive fermionic modes and the properties of the analogue quantum-potential near the origin.

Evaluation of a Limited-area Energy Budget Cycle of an Extratropical Storm Under Lagrangian and Eulerian Frameworks

To conceptualize the uncertainties regarding the mechanisms of extratropical cyclones (EC), a study of their energy cycle can provide key information of their fundamental structure. This study applies a set of equations built from earlier works for a limited-area energy decomposed into temporal mean and deviations. It compares the results obtained with a reference frame that tracks an EC through its eddy kinetic energy with those obtained with a larger but fixed frame. A specific storm that occurred throughout the period of December 10-18th 2004 and simulated by the Canadian Regional Climate Model (CRCM – version 5) was studied. Results support the notion that the moving reference results in larger amplitudes for all temporal deviation components of the cycle than for the fixed reference. A time tendency analysis of the energetic reservoirs reveals noteworthy phases in the storm’s energy, with an increase and decrease occurring during the periods of 10-14 December and 14-18 December, respectively. The energy budget is overall fairly well balanced, with the exception of a lateral boundary term, hkTV , with considerable negative values; this term exhibits a spatially larger scale than the other contributions in the EC. An evaluation of the sensibility of the tracking scheme related to its size and positioning was also performed to determine its influence on the boundary term hkTV.