Seeing the Invisible: Machine learning-Based QPI Kernel Extraction via Latent Alignment

Quasiparticle interference (QPI) imaging is a powerful tool for probing electronic structures in quantum materials, but extracting the single-scatterer QPI pattern (i.e., the kernel) from a multi-scatterer image remains a fundamentally ill-posed inverse problem. In this work, we propose the first AI-based framework for QPI kernel extraction. We introduce a two-step learning strategy that decouples kernel representation learning from observation-to-kernel inference. In the first step, we train a variational autoencoder to learn a compact latent space of scattering kernels. In the second step, we align the latent representation of QPI observations with those of the pre-learned kernels using a dedicated encoder. This design enables the model to infer kernels robustly even under complex, entangled scattering conditions. We construct a diverse and physically realistic QPI dataset comprising 100 unique kernels and evaluate our method against a direct one-step baseline. Experimental results demonstrate that our approach achieves significantly higher extraction accuracy, and improved generalization to unseen kernels.

@article{ji2025_2506.05325,
  title={ Seeing the Invisible: Machine learning-Based QPI Kernel Extraction via Latent Alignment },
  author={ Yingshuai Ji and Haomin Zhuang and Matthew Toole and James McKenzie and Xiaolong Liu and Xiangliang Zhang },
  journal={arXiv preprint arXiv:2506.05325},
  year={ 2025 }
}