Department de Física, Universitat Politécnica de Catalunya, Campus Nord B4-B5, E-08034, Barcelona, Spain.
Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona, E-08028, Barcelona, Spain.
Nat Commun. 2023 Mar 24;14(1):1647. doi: 10.1038/s41467-023-37153-0.
Induced interactions and bound states of charge carriers immersed in a quantum medium are crucial for the investigation of quantum transport. Ultracold atom-ion systems can provide a convenient platform for studying this problem. Here, we investigate the static properties of one and two ionic impurities in a bosonic bath using quantum Monte Carlo methods. We identify three bipolaronic regimes depending on the strength of the atom-ion potential and the number of its two-body bound states: a perturbative regime resembling the situation of a pair of neutral impurities, a non-perturbative regime that loses the quasi-particle character of the former, and a many-body bound state regime that can arise only in the presence of a bound state in the two-body potential. We further reveal strong bath-induced interactions between the two ionic polarons. Our findings show that numerical simulations are indispensable for describing highly correlated impurity models.
在量子介质中，被捕获的电荷载流子的诱导相互作用和束缚态对于量子输运的研究至关重要。超冷原子-离子体系为研究这一问题提供了一个便利的平台。在这里，我们使用量子蒙特卡罗方法研究了玻色子浴中一个和两个离子杂质的静态特性。我们根据原子-离子势的强度和其两体束缚态的数量确定了三种双极化子态：类似于一对中性杂质的微扰态、失去前一种准粒子特征的非微扰态，以及只有在两体势中有束缚态时才能出现的多体态束缚态。我们进一步揭示了两个离子极化子之间强烈的浴诱导相互作用。我们的研究结果表明，数值模拟对于描述高度相关的杂质模型是不可或缺的。
