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A: Fachverband Atomphysik
A 41: Ultracold Matter (Fermions) II (joint session Q/A)
A 41.7: Talk
Friday, March 14, 2025, 12:45–13:00, HS V
Formation of Cavity-Polaritons via Higher-Order Van Hove Singularities — •Igor Gianardi1, Michele Pini2, and Francesco Piazza2 — 1Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany — 2Institute of Physics, Universität Augs- burg, 86159 Augsburg, Germany
Polaritons are hybrid quasi-particles that blend matter and light properties. We consider their realization here through the hybridization of interband particle-hole excitations from an insulating phase with a cavity photon at sub-gap frequencies, where absorption is suppressed. The strength of the hybridization is driven by the Van Hove singularity in the joint density of states at the band gap: the stronger the singularity, the greater the photon hybridization with interband excitations. One way to enhance the Van Hove singularity strength is by reducing the system's dimensionality, such as using one-dimensional nanowires [1]. Alternatively, a promising approach involves tailoring a non-parabolic momentum dispersion of the bands around the gap to implement a higher-order Van Hove singularity (HOVHS). Building on this intuition, we propose to employ ultracold atom platforms and leverage the tunability of optical lattices to engineer two-dimensional gapped phases with non-trivial band dispersions at the gap. Our findings position ultracold atoms in cavities as an ideal platform to explore the emerging field of Van Hove polaritonics, opening a new route to quantum nonlinear optics.
[1] K. B. Arnardottir et al., Phys. Rev. B 87, 125408 (2013)
Keywords: Polaritons; Van Hove Singularities; Cavity; Chequerboard; Quantum Nonlinear Optics