Quantum Complexity has emerged in the past few years as a good candidate for quantum chaos diagnostic. This talk is based on a couple of works, in which we show that a notion of quantum complexity (spread complexity) is sensitive to Topological Phase Transitions. I’ll give a brief overview of what we mean when we say “quantum” chaos and proceed to discuss our results by introducing the Krylov subspace methods as well as a couple of simple methods to compute spread complexity.

Please contact phweb@ust.hk should you have questions about the talk.