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Production scientifique
Théorie des Champs & Physique Mathématique
(21) Production(s) de l'année 2016
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D-instantons, mock modular forms and BPS partition functions
Auteur(s): Alexandrov S.
(Séminaires)
CERN (Geneve, SZ), 2016-10-04
Résumé: I'll discuss the modular properties of D3-brane instantons appearing in Calabi-Yau string compactifications. I'll show that the D3-instanton contribution to a certain geometric potential on
the hypermultiplet moduli space can be related to the elliptic genus of (0,4) SCFT. The modular properties of the potential imply that the elliptic genus associated with non-primitive divisors
of Calabi-Yau is only mock modular. I'll show how to construct its modular completion and to make manifest the modular invariance of the twistorial construction of D-instanton corrected hypermultiplet
moduli space.
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D-instantons, mock modular forms and BPS partition functions
Auteur(s): Alexandrov S.
(Séminaires)
Instituto Superior Técnico (Lisbonne, PT), 2016-06-06
Résumé: I will discuss the modular properties of D3-brane instantons appearing in Calabi-Yau string compactifications. I will show that the D3-instanton contribution to a certain geometric potential on the hypermultiplet moduli space can be related to the elliptic genus of (0,4) SCFT. The modular properties of the potential imply that the elliptic genus associated with non-primitive divisors of Calabi-Yau is only mock modular. I will show how to construct its modular completion and prove the modular invariance of the twistorial construction of D-instanton corrected hypermultiplet moduli space.
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D-instantons, mock modular forms and BPS partition functions
Auteur(s): Alexandrov S.
(Séminaires)
IHES (Bures-sur- Yvette, FR), 2016-05-24
Résumé: I'll discuss the modular properties of D3-brane instantons
appearing in Calabi-Yau string compactifications. I'll show that
the D3-instanton contribution to a certain geometric potential on
the hypermultiplet moduli space can be related to the elliptic
genus of (0,4) SCFT. The modular properties of the potential imply
that the elliptic genus associated with non-primitive divisors
of Calabi-Yau is only mock modular. I'll show how to construct
its modular completion and prove the modular invariance of the
twistorial construction of D-instanton corrected hypermultiplet
moduli space.
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Instantons, wall-crossing and quantum dilogarithm identities
Auteur(s): Alexandrov S.
(Séminaires)
LAPTh (Annecy, FR), 2016-01-29
Résumé: I'll review the phenomenon of wall-crossing in theories with N=2 supersymmetry and its relation to the instanton contributions to the low energy effective actions in gauge and string theories. In the latter case, it is relevant for the description of D-brane instantons. Adding NS5-brane instantons to the story, one arrives to considering certain generalized theta series. I'll derive the properties of these theta series following from the mutual consistency of wall-crossing, D-brane and NS5-brane instantons, and show how these results can be used to get a new type of quantum dilogarithm identities.
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Collective behavior of quantum resonators coupled to a metamaterial
Auteur(s): Felbacq D., Rousseau E.
Conference: ACTIVE PHOTONIC MATERIALS VIII (San-Diego, US, 2016)
Actes de conférence: Proceedings of SPIE, vol. 9920 p.UNSP 99200X (2016)
Ref HAL: hal-01436058_v1
DOI: 10.1117/12.2237121
WoS: WOS:000390409500007
Exporter : BibTex | endNote
Résumé: We study a device that consist of quantum resonators coupled to a mesoscopic photonic structure, such as a metasurface or a 2D metamaterial. For metasurfaces, we use surface Bloch modes in order to reach various coupling regimes between the metasurface and a quantum emitter, modelized semi-classically by an oscillator. Using multiple scattering theory and complex plane techniques, we show that the coupling can be characterized by means of a pole-and-zero structure. The regime of strong coupling is shown to be reached when the pole-and- zero pair is broken. For 2D metamaterial, we show the possibility of controlling optically the opening or closing of a gap. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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Instantons, wall-crossing and quantum dilogarithm identities
Auteur(s): Alexandrov S.
Conférence invité: 2nd French Russian Conference Random Geometry and Physics (Paris, FR, 2016-10-17)
Ref HAL: hal-01386647_v1
Exporter : BibTex | endNote
Résumé: Motivated by mathematical structures appearing in gauge and string theories with N=2 supersymmetry, I’ll consider the behavior of certain generalized theta series under Kontsevich-Soibelman transformations. In Calabi-Yau string vacua, such theta series encode instanton corrections from NS5-branes, and their transformation properties ensure the mutual consistency of NS5-instantons, D-instantons and wallcrossing. It turns out that the transformations are captured by Faddeev’s quantum dilogarithm, and lead to a new type of quantum dilogarithm identities with the quantization parameter inversely proportional to the NS5-brane charge.
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Optical properties of G centers
Auteur(s): Beaufils C., Rousseau E., Cassabois G.
Conférence invité: Advances in Photonics and Applications (Florence, IT, 2016-06-09)
Ref HAL: hal-01358451_v1
Exporter : BibTex | endNote
Résumé: I will review our recent experiments revisiting the optical properties of G centers in silicon.
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