5 papers
Role of Quantum Geometry in the Competition between Higgs Mode and Quasiparticles in Third-Harmonic Generation of Superconductors
Chang-geun Oh, Haruki Watanabe, Naoto Tsuji
Collective modes in superconductors, such as the Higgs mode, offer deep insights into the nature of condensates. Third-harmonic generation (THG) is a primary tool for probing the H…
Projective Representations, Bogomolov Multiplier, and Their Applications in Physics
Ryohei Kobayashi, Haruki Watanabe
We present a pedagogical review of projective representations of finite groups and their physical applications in quantum many-body systems. Some of our physical results are new. W…
Gauge-invariant electromagnetic responses in superconductors
Sena Watanabe, Haruki Watanabe
Gauge invariance is essential for making physically meaningful predictions. In superconductors, mean-field Hamiltonians that explicitly break symmetry often yield gauge-depe…
generalizations of three-dimensional stabilizer codes
Chanbeen Lee, Yaozong Hu, Gil Young Cho +1
In this work, we generalize several three-dimensional Z2 stabilizer models--including the X-cube model, the three-dimensional toric code, and Haah's code--to their ZN counterparts.…
A gauge-invariant formulation of optical responses in superconductors
Sena Watanabe, Haruki Watanabe
Superconductors are often discussed in the mean-field approximation that breaks symmetry. Since the symmetry underlies the charge conservation, naive application of r…