报告题目：通过周期驱动光晶格势的幅度和周期实现的可调控性Floquet-Bloch能带(Tunable Floquet-Bloch bands in optical lattices with amplitude modulation and periodic shaking)
报 告 人：严杨千 博士 (普度大学物理天文系 博士后)
报告时间：2017年9月30日（周六）14:00
报告地点：校本部G309
邀请人：张永平
报告摘要：
We propose a simple scheme to realize a Floquet topological insulator in an optical lattice by weakly modulating the lattice depth. When the modulation frequency resonantly couples the s and p bands, the Floquet Hamiltonian becomes topologically nontrivial. We map out the topological transition as a function of frequency and amplitude. An advantage of our scheme is that the modulation amplitude can be relatively small, so the heating can be minimal. Double modulation gives even broader control and greater tunability. We consider a combination of shaking and amplitude modulation with the same frequency and varying phase difference. The effective dispersion relation for a one-dimensional lattice is investigated as a function of modulation depths and relative phase. We find that the band structure displays asymmetry of which the magnitude can be tuned by varying the relative phase. The Spin-balanced Fermi gas with asymmetric band structure, together with $s$-wave interaction, is known as one possible realization of the Fulde-Ferrel superfluid.
