Ultracold Feshbach molecules in an orbital optical lattice

Abstract

Quantum gas systems provide a unique experimental platform to study the crossover between Bose–Einstein condensed molecular pairs and Bardeen–Cooper–Schrieffer superfluidity. The few studies in optical lattices have so far focused on the case when only the lowest Bloch band is populated, thus excluding orbital degrees of freedom. Here we demonstrate the preparation of ultracold Feshbach molecules of fermionic atoms in the second Bloch band of an optical square lattice. We cover a wide range of interaction strengths, including the regime of unitarity in the middle of the crossover. Binding energies and band relaxation dynamics are measured by means of a method resembling mass spectrometry. We find that the longest lifetimes arise for strongly interacting Feshbach molecules at the onset of unitarity. In the case of strong confinement in a deep lattice potential, we observe bound dimers also for negative values of the scattering length, extending previous findings for molecules in the lowest band.

Quantum simulation of ultracold atoms in optical lattice based on dynamical mean-field theory

“…最早在实验室观测到p能 带现象是2007年由Bloch研究组 [80] 实现的, 之后 汉堡大学的Hemmerich小组 [81,82] 利用二分晶格 p x + ip y (bipartite lattice)实现了正方晶格的p轨道玻色 凝聚, 并观测到p能带玻色系统中存在 的 手征超流. 近年来, 随着实验技术的不断提高, 三 角晶格、六角晶格的p轨道玻色系统和高轨道费米 系统 [83,84] 也已经被实现, 并观察到了非常有趣的 物理现象 [75,85−89] .…”

Realization of 87Rb Bose–Einstein Condensates in Higher Bands of a Hexagonal Boron-Nitride Optical Lattice

“…[16][17][18][19]21,22,[24][25][26][27][28][29][30][31][32][33][34] Recent studies also report that fermionic atoms and Feshbach molecules are prepared in higher Bloch bands of a square lattice. [35,36] However, the higher-orbital atoms possess shorter lifetime, owing to the collision-induced band relaxation. [26,[37][38][39][40] Severe heating effects hinder the formation and lead to faster decay of the condensate, even though the atoms could be pumped into the excited band.…”