Title: Formation of Cavity-Polaritons via High-Order Van Hove Singularities Show Chinese title

Title: 通过高阶Van Hove奇点形成空腔极子

Abstract: We consider polaritons formed by hybridizing particle-hole excitations of 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 JDOS at the band gap: the stronger the singularity, the more a photon is hybridized with the interband transitions. In order to increase the singularity and thus the polariton hybridization without absorption, we propose to engineer a non-parabolic momentum dispersion of the bands around the gap in order to implement a high-order Van Hove singularity (HOVHS) in the JDOS. Ultracold atoms in tunable optical lattices are an ideal platform to engineer two-dimensional gapped phases with non-trivial band dispersions at the gap. Moreover, the intrinsic non-interacting nature of polarized fermionic atoms prevents the emergence of sub-gap excitations, which are common in solid-state systems and could otherwise spoil the absence of absorption below the gap. Our findings identify band-engineering at the gap edge as a promising route for polariton control with applications in quantum-nonlinear optics. Show Chinese abstract

Abstract: 我们考虑在带隙以下频率下，通过将绝缘相的粒子-空穴激发与腔光子杂化而形成的极化子，此时吸收被抑制。 杂化的强度由带隙处JDOS中的范霍夫奇异性驱动：奇异性越强，光子与带间跃迁的杂化程度越高。 为了在不产生吸收的情况下增强奇异性并从而增强极化子杂化，我们提出工程化带隙附近的非抛物动量色散，以在JDOS中实现高阶范霍夫奇异性（HOVHS）。 可调谐光学晶格中的超冷原子是工程化二维带隙相的理想平台，这些带隙相在带隙处具有非平凡的能带色散。 此外，极化费米原子的固有非相互作用性质防止了亚带隙激发的出现，而在固态系统中这些激发很常见，否则会破坏带隙以下的无吸收特性。 我们的研究结果表明，在带隙边缘进行能带工程是一种用于极化子控制的有前途的方法，并在量子非线性光学中有应用前景。