Christianen Arthur, Cirac J Ignacio, Schmidt Richard
Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany.
Munich Center for Quantum Science and Technology (MCQST), Schellingstraße 4, D-80799 Munich, Germany.
Phys Rev Lett. 2022 May 6;128(18):183401. doi: 10.1103/PhysRevLett.128.183401.
Similar to an electron in a solid, an impurity in an atomic Bose-Einstein condensate (BEC) is dressed by excitations from the medium, forming a polaron quasiparticle with modified properties. This impurity can also undergo chemical recombination with atoms from the BEC, a process resonantly enhanced when universal three-body Efimov bound states cross the continuum. To study the interplay between these phenomena, we use a Gaussian state variational method able to describe both Efimov physics and arbitrarily many excitations of the BEC. We show that the polaron cloud contributes to bound state formation, leading to a shift of the Efimov resonance to smaller interaction strengths. This shifted scattering resonance marks the onset of a polaronic instability towards the decay into large Efimov clusters and fast recombination, offering a remarkable example of chemistry in a quantum medium.
类似于固体中的电子，原子玻色 - 爱因斯坦凝聚体（BEC）中的杂质会被介质中的激发所修饰，形成具有修改后性质的极化子准粒子。这种杂质还可以与BEC中的原子进行化学重组，当通用三体埃菲莫夫束缚态穿过连续谱时，该过程会发生共振增强。为了研究这些现象之间的相互作用，我们使用了一种高斯态变分方法，该方法能够描述埃菲莫夫物理以及BEC的任意多个激发。我们表明，极化子云有助于束缚态的形成，导致埃菲莫夫共振向更小的相互作用强度移动。这种移动的散射共振标志着极化子不稳定性开始向衰变为大的埃菲莫夫簇和快速重组转变，为量子介质中的化学提供了一个显著的例子。
