Research Experience

non-Hermitian Physics

1. non-Hermitian Bloch Oscillation
   We investigate the Bloch Oscillation (BO) in non-Hermitian Hatano-Nelson (HN) model. The non-reciprocal hoppings in HN model can lead to non-Hermitian skin effect (NHSE) while electric field will lead to Wannier-Strak localization (WSL). The competition between them will enrich wavepacket dynamics such as asymmetric Bloch oscillation and some novel edge dynamics. We derive the semiclassical equations of motion to describe wavepacket dynamics and have observed these phenomena in acoustic lattices.
2. Chiral Landau-Zener Tunneling
   Wannier-Stark exceptional points (EPs) in non-Hermtian SSH model under a uniform electric field can induce chiral Landau-Zener tunneling, which has a tight relation with Floquet EPs (Longhi, PRL, 2022). We design the acoustic lattice to experimentally demonstrate such effect.
3. Twinkling Bloch Oscillation
   We considered BO in anti-Hermitian HN lattices. The purely imaginary band due to anti-Hermicity can give a zero group velocity, which will freeze the motion in real space. However, the nonzero imaginary part of spectrum gives a normalizaiton oscillation like twinkling stars visually. We have observed TBO in acoustic lattices. And this effect can be extended to long-range coupling system to obtain what we name "pseudo-fractional" Bloch oscillation.

Condensed Matter Experiment

1. Spin Polarized STM Tips
   In the summer of 2023 I conducted summer research at Fudan University in Yuanbo Zhang's group. My major work is to make a spin-polarized STM tips to probe magnetic properties of materials by vapor-depositing Cr atoms on the tungsten needle tips. However I spent lots of time on SolidWorks to design structure of tip-holder. After that summer I convience myself that I don't like such experiments.

Condensed Matter Theory

1. Magnetism
   Now I'm studying some novel magnetism in materials, which is also my undergraduate thesis.
2. non-Hermitian effects in real materials?
   I also hope to find some non-Hermitian effects in true materials, not just in artifical meta-materials (photonic/phononic crystals, circuits et.cl).

Tools

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