107 research outputs found
Preliminary Analysis of the PreFlexMS Molten Salt Once-Through Steam Generator Dynamics and Control Strategy
No full textLes vecteurs singuliers de l'algèbre superconforme dans le secteur de Ramond en termes de superpolynômes de Jack
No full textCe mémoire fait état des résultats obtenus concernant les vecteurs singuliers de l’algèbre superconforme dans le secteur de Ramond. Une formule explicite exprimant ces vecteurs singuliers a été obtenue en termes de superpolynômes de Jack via la représentation de l’algèbre superconforme en termes de superpolynômes symétriques. On présente d’abord les partitions d’entiers et les fonctions symétriques standards. Ceci permet d’introduire les fonctions propres du modèle Calogero-Sutherland (CS) en termes de polynômes de Jack qui se révèlent être une représentation efficace des vecteurs singuliers de l’algèbre conforme. Suivant cette piste, on procède à la supersymétrisation du modèle CS ce qui permet de générer les superpolynômes de Jack, polynômes symétriques dans le superespace. On présente finalement la formule explicite des vecteurs singuliers de l’algèbre superconforme en termes de superpolynômes de Jack.This mémoire presents results concerning the Ramond singular vectors of the superconformal algebra. An explicit formula has been obtained for the Ramond singular vectors of the superconformal algebra via its superpolynomial representation and the formula is given here in terms of Jack superpolynomials. We first present some basic elements of the integer partition and symmetric functions theories. This leads us to consider the eigenfunctions of the Calogero-Sutherland (CS) model, the Jack polynomials. These happen to be the singular vectors of the conformal algebra when represented in terms of symmetric polynomials. Given those results, we extend the CS model to the supersymmetric case and interpret its eigenfunctions as the Jack superpolynomials which are symmetric functions in superspace. We then display the explicit formula of the Ramond singular vectors of the superconformal algebra which has been obtained in terms of Jack superpolynomials
Randall-Sundrum with Kalb-Ramond field: return of the hierarchy problem?
No full textSherpa Romeo green journal. Permission to archive author manuscript.We show that when the antisymmetric Kalb-Ramond field is included in the
Randall-Sundrum scenario, although the hierarchy problem can be solved, it requires an
extreme fine tuning of the Kalb-Ramond field (about 1 part in 1062). We interpret this as the
return of the problem in disguise. Further, we show that the Kalb-Ramond field induces a
small negative cosmological constant on the visible brane.N
Closed string Ramond–Ramond proposed higher derivative interactions on fermionic amplitudes in IIB
No full textAbstractThe complete form of the amplitude of one closed string Ramond–Ramond (RR), two fermionic strings and one scalar field in IIB superstring theory has been computed in detail. Deriving 〈VCVψ¯VψVϕ〉 by using suitable gauge fixing, we discover some new vertices and their higher derivative corrections. We investigate both infinite gauge and scalar u-channel poles of this amplitude. In particular, by using the fact that the kinetic term of fermion fields has no correction, employing Born–Infeld action, the Wess–Zumino terms and their higher derivative corrections, we discover all infinite t,s-channel fermion poles. The couplings between one RR and two fermions and all their infinite higher derivative corrections have been explored. In order to look for all infinite (s+t+u)-channel scalar/gauge poles for p+2=n, p=n cases, we obtain the couplings between two fermions–two scalars and two fermions, one scalar and one gauge field as well as all their infinite higher derivative corrections in type IIB. Specifically we make various comments based on arXiv:1205.5079 in favor of universality conjecture for all order higher derivative corrections (with or without low energy expansion) and the relation of open/closed string that is responsible for all superstring scattering amplitudes in IIA, IIB
Beyond Mathieu Moonshine: a look at large N = 4 Algebras.
No full text\small{The conformal field theory approach to calculate the elliptic genus of surfaces has revealed the Mathieu moonshine phenomenon, which highlights relations between the `small' superconformal algebra at central charge , the sporadic group Mathieu 24 and mock modular forms. Here we take a look at a family of 'large' superconformal algebras, labelled \mathcal A_\gamma, \gamma \in [\hf, \infty [ (from which one can recover the small algebras in some limit), in the hope that a moonshine-like phenomenon might be observed. We consider realizations of and its closely related family of non-linear algebras \Atg on , where is a 4-dimensional Wolf space, i.e. a quaternionic symmetric space. The underlying physical models are supersymmetric Wess-Zumino-Novikov-Witten models describing superstring propagation on the group manifold, for which explicit partition functions can be constructed. In order to exhibit the \Atg (and ) symmetries of these models at the level of partition functions, we construct character sum rules which encode how products of affine characters with a character for four `Wolf space' fermions decompose as sums of \Atg characters. We find close analytic forms for the corresponding branching functions in a theory with \Atg symmetry where the levels of the two affine subalgebras of \Atg are \ktp=2 and \ktm=1, and we discover that they form a vector-valued mock modular form of weight . To arrive at this result, we used the transformation laws of the \Atg characters under the modular group , which we derive in the twisted Ramond sector.
Readdressing the hierarchy problem in a Randall-Sundrum scenario with bulk Kalb-Ramond background
No full textSherpa Romeo green journal. “This is an author-created, un-copyedited version of an article accepted for publication/published in Classical and Quantum Gravity. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it.”We re-examine the fine tuning problem of the Higgs mass, when an antisymmetric two form
Kalb-Ramond (KR) field is present in the bulk of a Randall-Sundrum (RS) braneworld. Taking into
account the back-reaction of the KR field, we obtain the exact correction to the RS metric. The
modified metric also warps the Higgs mass from Planck scale (in higher dimension) to TeV scale
(on the visible brane) for a range of values of kr exceeding the original RS value (where k = Planck
mass and r = size of extra dimension). However, it requires an extraordinary suppression of the
KR field density, indicating the re-appearence of the fine tuning problem in a different guise. The
new spacetime also generates a small negative cosmological constant on the visible brane. These
results are particularly relevant for certain string based models, where the KR field is unavoidably
present in the bulk. We further show that such a bulk antisymmetric KR field fails to stabilize the
braneworld.N
On RR couplings and bulk singularity structures of non-BPS branes
No full textAbstractWe compute the five point world sheet scattering amplitude of a symmetric closed string Ramond–Ramond, a transverse scalar field, a world volume gauge field and a real tachyon in both world volume and transverse directions of brane in type IIA and IIB superstring theory. We provide the complete analysis of <C−1ϕ0A0T−1> S-matrix and show that both u′=u+14 and t channel bulk singularity structures can also be examined by this S-matrix. Various remarks about new restricted Bianchi identities on world volume for the other pictures have also been made
The explanation of the deformed Schild string
No full textThe author comments on [1]. One of the deformed actions can express the Neveu-Schwarz-Ramond superstring under three gauge conditions. One of these depends on a matrix induced by the string coordinate.othe
The explanation of the deformed Schild string
No full textThe author comments on [1]. One of the deformed actions can express the Neveu-Schwarz-Ramond superstring under three gauge conditions. One of these depends on a matrix induced by the string coordinate
Construction of Pomeron states in the zero-width approximation
No full textThe author presents a kinematical construction for the Pomeron in models of relativistic composite particle in the zero-width approximation. (9 refs)
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