Topological phenomena in driven quantum gases

Stimulated by the recent progress in engineering topological band structures in cold atomic gases, we study the dynamic topological phenomena for atoms loaded in a periodically driven optical lattice. When the frequency of the periodic modulation is low, the time-dependent Hamiltonian can be mapped to a two-dimensional topological insulator, with the discretized frequency components playing the role of an additional, synthetic dimension. In the high-frequency limit, we derive the effective Floquet Hamiltonian of the system, and reveal the occurrence of Floquet dynamic quantum phase transitions---an emergent topological phenomenon in the micromotion of the Floquet dynamics. Addressing the relation between the topology of the effective Floquet Hamiltonian and the presence of dynamic topological phenomena, we demonstrate that the topologically nontrivial nature of the Floquet Hamiltonian is a sufficient but not necessary condition for the onset of the Floquet dynamic quantum phase transition. We further discuss the relation of the topology of the Floquet Hamiltonian with the existence of dynamic skyrmion structures in the emergent momentum-time manifold of the micromotion, as well as the fate of these dynamic topological phenomena when the modulation frequency decreases away from the high-frequency limit. Finally, making use of the rich level structures of $^{171}\mathrm{Yb}$ atoms, we show that the system under study can be implemented in a one-dimensional Raman lattice where states in the ${}^{1}{S}_{0}$ ground-state manifold are coupled by Raman beams with periodically modulated amplitudes.Stimulated by the recent progress in engineering topological band structures in cold atomic gases, we study the dynamic topological phenomena for atoms loaded in a periodically driven optical lattice. When the frequency of the periodic modulation is low, the time-dependent Hamiltonian can be mapped to a two-dimensional topological insulator, with the discretized frequency components playing the role of an additional, synthetic dimension. In the high-frequency limit, we derive the effective Floquet Hamiltonian of the system, and reveal the occurrence of Floquet dynamic quantum phase transitions---an emergent topological phenomenon in the micromotion of the Floquet dynamics. Addressing the relation between the topology of the effective Floquet Hamiltonian and the presence of dynamic topological phenomena, we demonstrate that the topologically nontrivial nature of the Floquet Hamiltonian is a sufficient but not necessary condition for the onset of the Floquet dynamic quantum phase transition. We further discuss the relation of the topology of the Floquet Hamiltonian with the existence of dynamic skyrmion structures in the emergent momentum-time manifold of the micromotion, as well as the fate of these dynamic topological phenomena when the modulation frequency decreases away from the high-frequency limit. Finally, making use of the rich level structures of $^{171}\mathrm{Yb}$ atoms, we show that the system under study can be implemented in a one-dimensional Raman lattice where states in the ${}^{1}{S}_{0}$ ground-state manifold are coupled by Raman beams with periodically modulated amplitudes.

arXiv:2112.15141Physical Review AApr 20, 20227 citations

Phase slips driven by acoustic waves in Bose-Einstein condensates with ring topology

Yevhenii Kuriatnikov, A. O. Olashyn, A. I. Yakimenko

Rotational superradiance is one of the most fascinating phenomena in black-hole physics. Here, with the aim of probing quantum properties of superradiance in the lab, we investigate the interaction of the acoustic waves with quantum vortices in Bose-Einstein condensates (BEC) in the framework of dissipative mean-field model. We find the conditions of the acoustic-induced quantum phase slips in condensates with ring topology and discuss the possibility of observing an acoustic analogue of quantum superradiance in ultracold atomic gases.Rotational superradiance is one of the most fascinating phenomena in black-hole physics. Here, with the aim of probing quantum properties of superradiance in the lab, we investigate the interaction of the acoustic waves with quantum vortices in Bose-Einstein condensates (BEC) in the framework of dissipative mean-field model. We find the conditions of the acoustic-induced quantum phase slips in condensates with ring topology and discuss the possibility of observing an acoustic analogue of quantum superradiance in ultracold atomic gases.

arXiv:2008.07649Aug 17, 20200 citations

Numerical Simulations of Cooling and Topological Excitations of Quantum Gases

Jan Max Walter Krüger

Jan 1, 20040 citations

^{171}\mathrm{Yb}

atoms, we show that the system under study can be implemented in a one-dimensional Raman lattice where states in the

{}^{1}{S}_{0}

ground-state manifold are coupled by Raman beams with periodically modulated amplitudes.