84 citations · 656 across the 27 of their papers we have counts for
24 papers · 1 filter
Controlling particle current in a many-body quantum system by external driving
Shuto Mizuno, Kazuya Fujimoto, Yuki Kawaguchi
We propose a method to control the particle current of a one-dimensional quantum system by resonating two many-body states through an external driving field. We consider the Bose-H…
Designing nontrivial one-dimensional Floquet topological phases using a spin-1/2 double-kicked rotor
Yusuke Koyama, Kazuya Fujimoto, Shuta Nakajima +1
A quantum kicked rotor model is one of the promising systems to realize various Floquet topological phases. We consider a double-kicked rotor model for a one-dimensional quasi-spin…
Spin-wave growth via Shapiro resonances in a spinor Bose-Einstein condensate
Yuya Imaeda, Kazuya Fujimoto, Yuki Kawaguchi
We theoretically study the resonant phenomenon in a spin-1 Bose-Einstein condensate periodically driven by a quadratic Zeeman coupling. This phenomenon is closely related to the Sh…
Dynamical Scaling of Surface Roughness and Entanglement Entropy in Disordered Fermion Models
Kazuya Fujimoto, Ryusuke Hamazaki, Yuki Kawaguchi
Localization is one of the most fundamental interference phenomena caused by randomness, and its universal aspects have been extensively explored from the perspective of one-parame…
Magnetic soliton: from two to three components with SO(3) symmetry
Xiao Chai, Di Lao, Kazuya Fujimoto +1
Recent theoretical and experimental research has explored magnetic solitons in binary Bose-Einstein condensates (BECs). Here we demonstrate that such solitons are part of an SO(3)…
Magnetic solitons in a spin-1 Bose-Einstein condensate
Xiao Chai, Di Lao, Kazuya Fujimoto +3
Vector solitons are a type of solitary, or non-spreading wavepacket occurring in a nonlinear medium comprised of multiple components. As such, a variety of synthetic systems can be…
Family-Vicsek Scaling of Roughness Growth in a Strongly Interacting Bose Gas
Kazuya Fujimoto, Ryusuke Hamazaki, Yuki Kawaguchi
Family-Vicsek scaling is one of the most essential scale-invariant laws emerging in surface-roughness growth of classical systems. In this Letter, we theoretically elucidate the em…
Scale-invariant relaxation dynamics in two-component Bose-Einstein condensates with large particle-number imbalance
Kazuya Fujimoto, Kazunori Haneda, Kazue Kudo +1
We theoretically study the scale-invariant relaxation dynamics in segregating two-component Bose-Einstein condensates with large particle-number imbalance, and uncover that random…
Floquet Spinor Bose Gases
Kazuya Fujimoto, Shun Uchino
We introduce a Floquet spinor Bose-Einstein condensate induced by a periodically driven quadratic Zeeman coupling whose frequency is larger than any other energy scales. By examini…
Flemish Strings of Magnetic Solitons and a Non-Thermal Fixed Point in a One-Dimensional Antiferromagnetic Spin-1 Bose Gas
Kazuya Fujimoto, Ryusuke Hamazaki, Masahito Ueda
Thermalization in a quenched one-dimensional antiferromagnetic spin-1 Bose gas is shown to proceed via a non-thermal fixed point through annihilation of Flemish-string bound states…
Synthetic dissipation and cascade fluxes in a turbulent quantum gas
Nir Navon, Christoph Eigen, Jinyi Zhang +6
Scale-invariant fluxes are the defining property of turbulent cascades, but their direct measurement is a notorious problem. Here we perform such a measurement for a direct energy…
Unconventional Universality Class of One-Dimensional Isolated Coarsening Dynamics in a Spinor Bose Gas
Kazuya Fujimoto, Ryusuke Hamazaki, Masahito Ueda
By studying the coarsening dynamics of a one-dimensional spin-1 Bose-Hubbard model in a superfluid regime, we analytically find an unconventional universal dynamical scaling for th…
Numerical Studies of Quantum Turbulence
Makoto Tsubota, Kazuya Fujimoto, Satoshi Yui
We review numerical studies of quantum turbulence. Quantum turbulence is currently one of the most important problems in low temperature physics and is actively studied for superfl…
Direct and inverse cascades of spin-wave turbulence in spin-1 ferromagnetic spinor Bose-Einstein condensates
Kazuya Fujimoto, Makoto Tsubota
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. T…
Bogoliubov-wave turbulence in Bose-Einstein condensates
Kazuya Fujimoto, Makoto Tsubota
We theoretically and numerically study Bogoliubov-wave turbulence in three-dimensional atomic Bose-Einstein condensates with the Gross-Pitaevskii equation, investigating three spec…
Spin-superflow turbulence in spin-1 ferromagnetic spinor Bose-Einstein condensates
Kazuya Fujimoto, Makoto Tsubota
Spin-superflow turbulence (SST) in spin-1 ferromagnetic spinor Bose-Einstein condensates is theoretically and numerically studied by using the spinor Gross-Pitaevskii (GP) equation…
Spin turbulence in spinor Bose-Einstein condensates
Makoto Tsubota, Kazuya Fujimoto
We summarize the recent theoretical and numerical works on spin turbulence (ST) in spin-1 spinor Bose-Einstein condensates. When the system is excited from the ground state, it goe…
Spin turbulence with small spin magnitude in spin-1 spinor Bose-Einstein condensates
Kazuya Fujimoto, Makota Tsubota
We theoretically and numerically study spin turbulence (ST) with small spin magnitude in spin-1 spinor Bose-Einstein condensates by using the spin-1 spinor Gross-Pitaevskii (GP)equ…
Spin-glass-like behavior in the spin turbulence of spinor Bose-Einstein condensates
Makoto Tsubota, Yusuke Aoki, Kazuya Fujimoto
We study numerically the spin turbulence in spin-1 ferromagnetic spinor Bose-Einstein condensates (BECs). Spin turbulence (ST) is characterized by a -7/3 power law in the spectrum…
Spin Turbulence in a Trapped Spin-1 Spinor Bose--Einstein Condensate
Kazuya Fujimoto, Makoto Tsubota
We numerically study spin turbulence in a two-dimensional trapped spin-1 spinor Bose--Einstein condensate, focusing on the energy spectrum. The spin turbulence in the trapped syste…
Counterflow instability and turbulence in a spin-1 spinor Bose--Einstein condensate
Kazuya Fujimoto, Makoto Tsubota
We theoretically study counterflow instability and turbulence in a spin-1 spinor Bose--Einstein condensate by the Gross--Pitaevskii equation and the Bogoliubov--de Gennes equation.…
Nonlinear Dynamics in a Trapped Atomic Bose--Einstein Condensate Induced by an Oscillating Gaussian Potential
Kazuya Fujimoto, Makoto Tsubota
We consider a trapped atomic Bose--Einstein condensate penetrated by a repulsive Gaussian potential and theoretically investigate the dynamics induced by oscillating the Gaussian p…
Synergy Dynamics of Vortices and Solitons in Atomic Bose-Einstein Condensate Excited by an Oscillating Potential
Kazuya Fujimoto, Makoto Tsubota
The hydrodynamics of quantized vortices and solitons in an atomic Bose-Einstein condensate excited by an oscillating potential are studied by numerically solving the two-dimensiona…
Dynamics of Vortices and Solitons in a Bose-Einstein Condensate by an Oscillating Potential
Kazuya Fujimoto, Makoto Tsubota
We study numerically the dynamics of quantized vortices and solitons induced by an oscillating potential inside a trapped Bose-Einstein condensate. The dynamics of the topological…