Sommaire:

The enhancement of light-matter interactions when the macroscopic number of quantum emitters in a semiconductor interact resonantly with a cavity mode has led to the observation of spectacular phenomena such as Bose-Einstein condensation at standard cryogenic temperature [1], polariton lasing [2], or light superfluidity [3]. In particular, the properties of the ground state are qualitatively affected in the so-called “ultrastrong” light-matter coupling regime, defined when the collective coupling strength becomes comparable to the bare cavity mode frequency [4]. I will first show that this regime can be achieved in quantum Hall systems with large filling factors [5,6,7], and explain how an interesting ultrastrong coupling regime with low loss can be realized by considering the two-dimensional electron gas embedded in a terahertz photonic band gap material. I will give an example of how this system could be used to observe the dynamical Casimir effect in realistic experimental conditions8. An other interest of quantum Hall systems is the existence of strong correlations due to the quenching of the kinetic energy, leading to exotic electronic phases in the
fractional filling factor regime. I will draw some perspectives on how an interesting interplay between Coulomb and light-matter interactions could be achieved by designing a suitable resonator made of hyperbolic metamaterials. Following the idea of exploring how light-matter coupling in a cavity can modify fermionic properties of condensed matter systems, I will then move to a simple two-band model to study the coherent transport of charges coupled to a cavity mode. In particular, charge current enhancements are predicted in the situation where lower and upper bandwidths are different9. I will conclude by showing how this simple model could be extended to describe incoherent transport in organic semiconductors, drawing a roadmap to enhance the efficiency of light emitting and collecting devices using cavity coupling.



1. Amo, A. et al., Nature Physics 5, 805 (2009)
2. Christopoulos, S. et al., Phys. Rev. Lett. 98, 126405 (2007)
3. Kasprzak, J. et al., Nature 443, 409 (2006)
4. Ciuti, C., Bastard, G. & Carusotto, I., Phys. Rev. B 72, 115303 (2005).
5. Hagenmüller, D., De Liberato, S. & Ciuti, C. Phys. Rev. B 81, 235303 (2010)
6. Scalari, G. et al. Science 335, 1323–1326 (2012)
7. Hagenmüller, D. & Ciuti, C. Phys. Rev. Lett. 109, 267403 (2012).
8. Hagenmüller, D. Phys. Rev. B 93, 235309 (2016)
9. Hagenmüller, D., Schachenmayer, J., Schütz, S., Genes, C. & Pupillo, G. (2017). ArXiv: 1703.00803v2
[quant-ph]. Accepted for publication in Phys. Rev. Lett.

Pour plus d'informations, merci de contacter Antezza M.