Light-matter interaction in photonic Weyl systems

• Autores: Iñaki García Elcano
• Directores de la Tesis: Jorge Bravo Abad (dir. tes.), Alejandro González Tudela (dir. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2024
• Idioma: inglés
• Número de páginas: 178
• Títulos paralelos:
  • Interacción luz-materia en sistemas fotónicos de Weyl
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Light-matter interactions play a central role in understanding the world around us.

    Their study has fueled significant advances enabling the expansion of the frontiers of knowledge and the design of novel technological applications. In this context, the extension of the ideas associated with the topological phases of matter to the photonics realm stands as an exciting challenge since they can modify the way in which these interactions take place. Topological light-matter interfaces can be exploited to obtain robust chiral quantum networks or to find new ways of probing topology in photonic platforms. At the same time, they can give rise to exotic regimes of interaction as a consequence of the non-linear character of the emitters that comprise the system.

    This includes the photonic counterparts of strongly interacting electronic states, such as the fractional quantum Hall effect.

    Among the zoo of topological photonic phases, Weyl photonic systems represent a paradigmatic example in the three-dimensional case. The bulk excitations of this gapless phase feature a dispersion relation that can be described by massless solutions of the relativistic Dirac equation. Furthermore, its topological nature is directly manifested by the presence of Fermi arc surface states that take the form of open curves in the surface Brillouin zone connecting the projection of Weyl points with different chirality. This thesis is devoted, precisely, to the characterization of the interplay between matter and such topological Weyl photons.

    We first study the coupling of one or more emitters to the bulk modes of a Weyl photonic bath. Using a lattice model to describe the photonic environment, we study the exact dynamics of the system. We find that the vanishing density of states displayed by a type I Weyl photonic phase facilitates the emergence of an atom-photon bound state. The latter defines a hybrid light-matter state featuring a power-law localization of its photonic part around the emitter’s position. We show that this atom-photon bound state mediates long-range, tunable, and robust interactions among emitters when more than one of them is embedded within the Weyl medium.

    Then, we investigate the quantum optical behavior of an interface formed by a set of emitters coupled to the Fermi arc surface modes. We demonstrate that such an interface can be used to probe the topological edge states by imaging the corresponding Fermi arcs. We also report on how this platform can be harnessed to design perfect quantum state transfer protocols or to entangle multiple emitters. Our findings evidence the great potential of the Fermi arc surface states to be leveraged for quantum technological applications.

    Finally, we explore a particular implementation of a Weyl photonic system in a subwavelength atomic array. We show that the dipolar interactions governing the behavior of the atomic ensemble when it is arranged following a cubic body-centered geometry give rise to a Weyl phase characterized by the presence of a single pair of frequency-isolated Weyl points. This condition permits to access the Weyl modes through the integration of additional impurity emitters resonant with the Weyl frequency.

    Besides, we study the edge modes of the system. These are affected by the collective dissipation effects induced by the interference of the atomic array’s spontaneously emitted photons