Title：Elementary excitations in quantum vortex and impurity atoms
Time：2024/03/18 (Mon.) 12:30
Place：R517, New Physics Building, NTU

Abstract：
Quantum vortex in superfluid Bose gas is a simplest example of topological solitons; already observed in early-time cold atom experiments. There appear elementary excitations : one is kelvon corresponding to the NG mode of translation symmetry breaking in the presence of vortex defect, and the other is Bogoliubov phonon to U(1) symmetry breaking for superfluidity. Interaction dynamics among them has yet to be fully understood. Here we have constructed the low-energy effective theory, and evaluate the radiative decay process of kelvons, which accounts for late time behavior of vortex excitation. We also present the polaron physics, i.e., an impurity atom, trapped in the vortex core, interacting with these elementary excitations to be a quasiparticle (polaron).