2 papers
cond-mat.quant-gas2020
Perfect transmission and perfect reflection of Bogoliubov quasiparticles in a dynamically unstable Bose-Einstein condensate
Terumichi Ohashi, Yuki Kawaguchi
The Nambu-Goldstone (NG) mode in a Bose-Einstein condensate (BEC) transmits a potential barrier with probability 1 in the zero-energy limit, which is known as the anomalous tunneli…
cond-mat.quant-gas2019
Generalized Berry phase for a bosonic Bogoliubov system with exceptional points
Terumichi Ohashi, Shingo Kobayashi, Yuki Kawaguchi
We discuss the topology of Bogoliubov excitation bands from a Bose-Einstein condensate in an optical lattice. Since the Bogoliubov equation for a bosonic system is non-Hermitian, c…