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Théorie des Champs & Physique Mathématique
(8) Production(s) de l'année 2019
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A nanowire-based telecom band single photon source monolithically grown on silicon 
Auteur(s): Jaffal Ali, Redjem W., Regreny Philippe, Nguyen Hai Son, Cueff Sébastien, Letartre Xavier, Patriarche Gilles, Rousseau E., Cassabois G., Gendry Michel, Chauvin Nicolas
(Affiches/Poster)
Journées Nationales Nanofils semiconducteurs (Ecully, FR), 2019-11-13
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Single photon emission with a Gaussian far-field at telecom wavelength from single InAs/InP quantum dot-nanowires monolithically grown on Si
Auteur(s): Jaffal Ali, Redjem W., Regreny Philippe, Nguyen Hai Son, Cueff Sébastien, Letartre Xavier, Patriarche Gilles, Rousseau E., Cassabois G., Gendry Michel, Chauvin Nicolas
Conference: Nanowire Week 2019 (Pise, IT, 2019-09-23)
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Twistors, black holes and modularity
Auteur(s): Alexandrov S.
Conférence invité: Twistors and Loops Meeting in Marseille (Marseille, FR, 2019-09-02)
Ref HAL: hal-02285107_v1
Exporter : BibTex | endNote
Résumé: I'll show how twistorial description of quaternionic geometries combined with string theory dualities helped to solve a long standing mathematical problem - to understand modular properties of indefinite theta series. Then I'll use the solution of this problem to describe the modular behavior of the generatingfunction of degeneracies of BPS black holes appearing in Calabi-Yau compactifications of string theory.
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Global properties of the growth index of matter inhomogeneities in the universe
Auteur(s): Calderon R., Felbacq D., Gannouji R., Polarski D., Starobinsky A.A.
(Article) Publié:
Physical Review D, vol. 100 p.083503 (2019)
Texte intégral en Openaccess : 
Ref HAL: hal-02266321_v1
Ref Arxiv: 1908.00117
Ref INSPIRE: 1747566
DOI: 10.1103/PhysRevD.100.083503
WoS: 000488510300002
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
1 Citation
Résumé: We perform here a global analysis of the growth index γ behavior from deep in the matter era till the far future. For a given cosmological model in general relativity (GR) or in modified gravity, the value of γ(Ωm) is unique when the decaying mode of scalar perturbations is negligible. However, γ∞, the value of γ in the asymptotic future, is unique even in the presence of a non-negligible decaying mode today. Moreover, γ becomes arbitrarily large deep in the matter era. Only in the limit of a vanishing decaying mode do we get a finite γ, from the past to the future in this case. We find further a condition for γ(Ωm) to be monotonically decreasing (or increasing). This condition can be violated inside GR for varying wDE though generically γ(Ωm) will be monotonically decreasing (like ΛCDM), except in the far future and past. A bump or a dip in Geff can also lead to a significant and rapid change in the slope dγdΩm. On a ΛCDM background, a γ substantially lower (higher) than 0.55 with a negative (positive) slope reflects the opposite evolution of Geff. In Dvali-Gabadadze-Porrati (DGP) models, γ(Ωm) is monotonically increasing except in the far future. While DGP gravity becomes weaker than GR in the future and wDGP→-1, we still get γ∞DGP=γ∞ΛCDM=23. In contrast, despite GeffDGP→G in the past, γ does not tend to its value in GR because dGeffDGPdΩm|-∞≠0.
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Bigravity with single graviton
Auteur(s): Alexandrov S.
Conférence invité: the Tenth Alexander Friedmann International Seminar on Gravitation and Cosmology (Saint-Petersburg, RU, 2019-06-24)
Ref HAL: hal-02185363_v1
Exporter : BibTex | endNote
Résumé: I'll present a new model inspired by ghost-free bigravity. Despite involving two metrics as the usual bigravity models, it describes only one gravitational interaction. Expanded around a large class of backgrounds, the model propagates a single massless graviton. At non-linear level it has 6 additional degrees of freedom, but they contain neither massive graviton, nor the Boulware-Deser ghost. Thus, the model represents an interesting modification of general relativity which might be relevant for cosmology.
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Optimizing the shape of InAs/InP quantum dot-nanowires grown by MBE on silicon for efficient light sources emitting in the telecom band
Auteur(s): Jaffal Ali, Regreny Philippe, Redjem W., Nguyen Hai Son, Cueff Sébastien, Letartre Xavier, Patriarche Gilles, Rousseau E., Cassabois G., Gendry Michel, Chauvin Nicolas
Conference: 20th European Workshop on Molecular Beam Epitaxy (Lenggries, DE, 2019-02-17)
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Classical and quantum integrable sigma models. Ricci flow, "nice duality" and perturbed rational conformal field theories
Auteur(s): Fateev V.
(Document sans référence bibliographique) 2019-02-07Texte intégral en Openaccess :
Ref HAL: hal-02023484_v1
Ref Arxiv: 1902.02811
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: We consider classical and quantum integrable sigma models and their relations with the solutions of renormalization group equations. We say that an integrable sigma model possesses the "nice" duality property if the dual quantum field theory has the weak coupling region. As an example, we consider the deformed $CP(n-1)$ sigma model with additional quantum degrees of freedom. We formulate the dual integrable field theory and use perturbed conformal field theory, perturbation theory, $S$-matrix, Bethe Ansatz and renormalization group methods to show that this field theory has the "nice" duality property. We consider also an alternative approach to the analysis of sigma models on the deformed symmetric spaces, based on the perturbed rational conformal field theories.
Commentaires: 37 pages
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