3 papers
cond-mat.str-el2026
Parameterized Families of Toric Code Phase: -duality family and higher-order anyon pumping
Shuhei Ohyama, Takamasa Ando, Ryan Thorngren
Within the toric-code phase, we study parameterized families of topologically ordered states. We construct - and -parameter families of local Hamiltonians and confirm their n…
cond-mat.str-el2026
Symmetry Spans and Enforced Gaplessness
Takamasa Ando, Kantaro Ohmori
Anomaly matching for continuous symmetries has been the primary tool for establishing symmetry enforced gaplessness - the phenomenon where global symmetry alone forces a quantum sy…
cond-mat.str-el2024
Gauge theory and mixed state criticality
Takamasa Ando, Shinsei Ryu, Masataka Watanabe
In mixed quantum states, the notion of symmetry is divided into two types: strong and weak symmetry. While spontaneous symmetry breaking (SSB) for a weak symmetry is detected by tw…