论文标题
观察$ 1/k^4 $ tails在扩展玻璃纤维中的杂质之后
Observation of $1/k^4$-tails after expansion of Bose-Einstein Condensates with impurities
论文作者
论文摘要
我们在相互作用的存在下膨胀后用稀释的自旋杂质测量玻色子凝结物（BEC）中的动量密度。我们观察到尾巴衰减为$ 1/k^4 $，在凝结物和杂质云中的大动量$ k $处。这些代数尾巴源自杂质 - bec相互作用，但它们的幅度大大超过了陷阱中平衡时两体接触相互作用的预期。此外，在没有杂质的情况下，在相互作用驱动的膨胀后测得的BEC密度未发现此类代数尾巴。这些结果突出了存在时杂质所扮演的关键作用，这是我们以前的工作中未考虑的可能性[phys。莱特牧师。 117，235303（2016）]。我们的测量结果表明，这些意外的代数尾巴源于在存在杂质 - 浴相互作用的情况下扩展的非平凡动力学。
We measure the momentum density in a Bose-Einstein condensate (BEC) with dilute spin impurities after an expansion in the presence of interactions. We observe tails decaying as $1/k^4$ at large momentum $k$ in the condensate and in the impurity cloud. These algebraic tails originate from the impurity-BEC interaction, but their amplitudes greatly exceed those expected from two-body contact interactions at equilibrium in the trap. Furthermore, in the absence of impurities, such algebraic tails are not found in the BEC density measured after the interaction-driven expansion. These results highlight the key role played by impurities when present, a possibility that had not been considered in our previous work [Phys. Rev. Lett. 117, 235303 (2016)]. Our measurements suggest that these unexpected algebraic tails originate from the non-trivial dynamics of the expansion in the presence of impurity-bath interactions.
