According to the mean-field theory a condensed Bose-Bose mixture collapses when the
interspecies attraction becomes stronger than the geometrical average of the intraspecies …

When continuous symmetry is spontaneously broken, there appear Nambu–Goldstone
modes (NGMs) with linear or quadratic dispersion relation, which is called type-I or type-II …

Abstract Lee-Huang-Yang (LHY) fluids are an exotic quantum matter dominated purely by
quantum fluctuations. Recently, the three-dimensional LHY fluids were observed in ultracold …

We theoretically and numerically study spin wave turbulence in spin-1 ferromagnetic spinor
Bose-Einstein condensates, finding direct and inverse cascades with power-law behavior …

We develop a general theory of spin-dependent Bragg spectroscopy for spinor Bose-
Einstein condensates. This spectroscopy involves using a density and spin-coupled optical …

Topological excitations are a special type of long-lived excitation that are impervious to
small perturbations in cold atom systems. This thesis aims to investigate properties of two …

Non-linear systems give rise to a rich array of phenomena including chaos, turbulence,
solitons, and dynamical instabilities. The great degree of experimental control over Bose …

This thesis presents novel theoretical results on two cold atomic systems with particular
emphasis on the order-by-disorder mechanism that they exhibit. The latter selects one or a …

In this talk, I will address two issues concerning spinor condensates. First, I will show that the
non-abelian feature of a synthetic gauge potential can be controlled and probed by using …

反強磁性相互作用を有するカイラル磁性体のモデルとして 1D 古典 Heisenberg chain
を考え連続体近似を行うと強磁性相互作用が働く場合と同様にソリトン解を与える方程式である …