Fluctuation-induced Light in Topological Systems

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• Mario Silveirinha, Universidade de Lisboa
• Wednesday 27 March 2019, 14:00-15:00
• Watson Building LT C (G24).

If you have a question about this talk, please contact Dr Miguel Navarro-Cia.

Topological materials and topological effects have elicited significant interest, first in the condensed-matter community [1, 2] and more recently in the photonics community [3]. The topological phases of systems with a broken time-reversal symmetry are usually classified by a topological integer: the Chern number. In condensed-matter systems, the Chern number has a clear physical interpretation: it is the quantum of the Hall conductivity of a 2D electron gas [2], and hence it determines the electronic transport for very low temperatures. In contrast, in optics the Chern index has not been linked to any physical entity, except that it is known that it gives the net number of gapless unidirectional edge states supported by an interface with a trivial material. In this talk, I will review the work of my group on topological photonics [4-9]. In particular, I will highlight that the photonic Chern number has a precise physical meaning as the quantum of the thermal fluctuation-induced light-angular momentum in a closed photonic insulator cavity [8]. The nontrivial value the light angular momentum expectation is due to a circulation of thermal energy in closed orbits, which may occur even when a system is in a thermodynamic equilibrium with a large reservoir [5]. I will show that this link between topological effects and fluctuation-induced light, gives a rather elegant proof of the bulk-edge correspondence [9].

[1] D. J. Thouless, M. Kohmoto, M. P. Nightingale, and M. den Nijs, “Quantized Hall Conductance in a Two-Dimensional Periodic Potential”, Phys. Rev. Lett., 49, 405, (1982). [2] F. D. M. Haldane, “Nobel lecture: Topological quantum matter,” Rev. Mod. Phys., 89, 040502, (2017). [3] L. Lu, J. D. Joannopoulos, M. Soljačić, “Topological photonics”, Nat. Photonics, 8, 821, (2014). [4] M. G. Silveirinha, “Chern Invariants for Continuous Media”, Phys. Rev. B, 92, 125153, 2015. [5] M. G. Silveirinha, “Topological Angular Momentum and Radiative Heat Transport in Closed Orbits”, Phys. Rev. B, 95, 115103, 2017. [6] M. G. Silveirinha, S. A. H. Gangaraj, G. W. Hanson, M. Antezza, “Fluctuation-induced forces on an atom near a photonic topological material”, Phys. Rev. A, 97, 022509, 2018. [7] S. A. Lannebère, M. G. Silveirinha, “Link between the photonic and electronic topological phases in artificial graphene”, Phys. Rev. B, 97, 165128, 2018. [8] M. G. Silveirinha, “Quantized Angular Momentum in Topological Optical Systems”, arXiv:1803.07121, (2018). [9] M. G. Silveirinha, “Proof of the bulk-edge correspondence through a link between topological photonics and fluctuation electrodynamics”, arXiv:1804.02190, (2018).

This talk is part of the Metamaterials and Nanophotonics Group Seminars series.

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• Bham Talks
• Metamaterials and Nanophotonics Group Seminars
• Watson Building LT C (G24)
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