RNS derivation of N -point disk amplitudes from the revisited S-matrix approach

Recently, in [7] we proposed a revisited S-matrix approach to efficiently find the bosonic terms of the open superstring low energy effective lagrangian (OSLEEL). This approach allows to compute the α′N terms of the OSLEEL using open superstring n -point amplitudes in which n is considerably lower than (N+2) (which is the order of the required amplitude to obtain those α′N terms by means of the conventional S-matrix approach). In this work we use our revisited S-matrix approach to examine the structure of the scattering amplitudes, arriving at a closed form for them. This is a RNS derivation of the formula first found by Mafra, Schlotterer and Stieberger [21] , using the pure spinor formalism. We have succeeded doing this for the 5, 6 and 7-point amplitudes. In order to achieve these results we have done a careful analysis of the kinematical structure of the amplitudes, finding as a by-product a purely kinematical derivation of the BCJ relations (for N=4,5,6 and 7 ). Also, following the spirit of the revisited S-matrix approach, we have found the α′ expansions for these amplitudes up to α′6 order in some cases, by only using the well known open superstring 4-point amplitude, cyclic symmetry and tree level unitarity: we have not needed to compute any numerical series or any integral involving polylogarithms, at any moment

Orbit based procedure for doublets of scalar fields and the emergence of triple kinks and other defects

In this work we offer an approach to enlarge the number of exactly solvable models with two real scalar fields in ( 1+1 )D. We build some new two-field models, and obtain their exact orbits and exact or numerical field configurations. It is noteworthy that a model presenting triple-kinks and double-flat-top lumps is among those new models

Comments on the T-dual of the gravity dual of D5-branes on S 3

We consider an abelian T-duality on a deformation of the gravitational solution of [1], which is the gravity dual of N c D5-branes wrapping a three-cycle inside a manifold that admits a G 2 structure. Performing the T-duality we find N c D4-branes wrapping a two-cycle with non-trivial antisymmetric fields in the NS-NS and RR sector. We study some aspects of its dual field theory and we compare with the original solution

Conformal inflation from the Higgs

We modify the conformal inflation set-up of [1], with a local Weyl invariance, a dynamical Planck scale and an SO(1, 1) invariance at high energies, in order to be able to identify the physical scalar with the physical Higgs at low energies, similar to the cyclic Higgs models of [2]. We obtain a general class of exponentially-corrected potentials that gives a generalized Starobinsky model with an infinite series of R p corrections, tracing a line in the ( r , n s ) plane for CMB fluctuations, with an r that can be made to agree with the recent BICEP2 measurement. Introducing a coupling different from the conformal value, thus breaking the local Weyl symmetry, leads nevertheless to a very strong attractor motion towards the generalized Starobinsky line

Open strings on D-branes from ABJM

We study open strings on giant gravitons (D-branes on cycles) in the ABJM/ AdS 4 × ℂℙ 3 correspondence. We find that their energy spectrum has the same form as the one for closed strings, with a nontrivial function of the coupling, avoiding BMN scaling. A similar, Cuntz oscillator, Hamiltonian description for the string (operators at strong coupling) to the AdS 5 case is valid also in this case

Aspects of semilocal BPS vortex in systems with Lorentz symmetry breaking

The existence is shown of a static self-dual semilocal vortex configuration for the Maxwell–Higgs system with a Lorentz-violating CPT-even term. The dependence of the vorticity upper limit on the Lorentz-symmetry-breaking term is also investigated

Pulsating strings from two-dimensional CFT on (T4)N/S(N)

We propose a state from the two-dimensional conformal field theory on the orbifold (T4)N/S(N) as a dual description for a pulsating string moving in AdS3 . We show that, up to first order in the deforming parameter, the energy in both descriptions has the same dependence on the mode number, but with a non-trivial function of the coupling

Exact solutions to Elko spinors in spatially flat Friedmann-Robertson-Walker spacetimes

In this paper we present exact solutions to the so-called Elko spinors for three models of expanding universe, namely the de Sitter, linear and the radiation type evolution. The study was restricted to flat, homogeneous and isotropic Friedmann-Robertson-Walker backgrounds. Starting with an Elko spinor we present the solutions for these cases and compare to the case of Dirac spinors. Besides, an attempt to use Elko spinors as a dark energy candidate in the cosmological context is investigated

Chiral transition of fundamental and adjoint quarks

The chiral symmetry breaking transition of quarks in the fundamental and adjoint representation is studied in a model where the gap equation contains two contributions, one containing a confining propagator and another corresponding to the exchange of one-dressed dynamically massive gluons. When quarks are in the fundamental representation the confinement effect dominates the chiral symmetry breaking while the gluon exchange is suppressed due to the dynamical gluon mass effect in the propagator and in the coupling constant. In this case the chiral and deconfinement transition temperatures are approximately the same. For quarks in the adjoint representation, due to the larger Casimir eigenvalue, the gluon exchange is operative and the chiral transition happens at a larger temperature than the deconfinement one

Static domain wall in braneworld gravity

In this paper we consider a static domain wall inside a 3-brane. Different from the standard achievement obtained in General Relativity, the analysis performed here gives a consistency condition for the existence of static domain walls in a braneworld gravitational scenario. Also the behavior of the domain wall’s gravitational field in the newtonian limit is shown