Schirotzek André, Wu Cheng-Hsun, Sommer Ariel, Zwierlein Martin W
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2009 Jun 12;102(23):230402. doi: 10.1103/PhysRevLett.102.230402. Epub 2009 Jun 8.
We have observed Fermi polarons, dressed spin-down impurities in a spin-up Fermi sea of ultracold atoms. The polaron manifests itself as a narrow peak in the impurities' rf spectrum that emerges from a broad incoherent background. We determine the polaron energy and the quasiparticle residue for various interaction strengths around a Feshbach resonance. At a critical interaction, we observe the transition from polaronic to molecular binding. Here, the imbalanced Fermi liquid undergoes a phase transition into a Bose liquid, coexisting with a Fermi sea.
我们已经观测到了费米极化子，即在超冷原子的自旋向上费米海中的自旋向下杂质。极化子在杂质的射频谱中表现为一个从宽广的非相干背景中出现的窄峰。我们确定了费什巴赫共振附近各种相互作用强度下的极化子能量和准粒子留数。在临界相互作用下，我们观测到了从极化子束缚到分子束缚的转变。在此，不平衡的费米液体经历相变成为一种与费米海共存的玻色液体。
