Quantum heat engines and refrigerators are open quantum systems, whose dynamics can be well understood using a non-Hermitian formalism. A prominent feature of non-Hermiticity is the existence of exceptional points (EPs), which has no counterpart in closed quantum systems. It has been shown in classical systems that dynamical encirclement in the vicinity of an EP, whether the loop includes the EP or not, could lead to chiral mode conversion. Here, we show that this is valid also for quantum systems when dynamical encircling is performed in the vicinity of their Liouvillian EPs (LEPs), which include the effects of quantum jumps and associated noise—an important quantum feature not present in previous works. We demonstrate, using a Paul-trapped ultracold ion, the first chiral quantum heating and refrigeration by dynamically encircling a closed loop in the vicinity of an LEP. We witness the cycling direction to be associated with the chirality and heat release (absorption) of the quantum heat engine (quantum refrigerator). Our experiments have revealed that not only the adiabaticity breakdown but also the Landau–Zener–Stückelberg process play an essential role during dynamic encircling, resulting in chiral thermodynamic cycles. Our observations contribute to further understanding of chiral and topological features in non-Hermitian systems and pave a way to exploring the relation between chirality and quantum thermodynamics.

量子热机和冰箱是开放的量子系统，其动力学可以使用非厄米形式主义得到很好的理解。非厄米性的一个显着特征是异常点（EP）的存在，这在封闭量子系统中没有对应物。经典系统已表明，EP 附近的动态包围，无论环路是否包含 EP，都可能导致手性模式转换。在这里，我们证明这对于量子系统来说也是有效的，当动态环绕在其Liouvillian EP（LEP）附近进行时，其中包括量子跃迁和相关噪声的影响——这是以前的工作中不存在的一个重要的量子特征。我们使用保罗捕获的超冷离子，通过动态环绕 LEP 附近的闭环，演示了第一个手性量子加热和制冷。我们发现循环方向与量子热机（量子冰箱）的手性和放热（吸收）有关。我们的实验表明，在动态环绕过程中，不仅绝热破坏而且朗道-齐纳-斯图克伯格过程也发挥着重要作用，从而导致手性热力学循环。我们的观察有助于进一步理解非厄米系统的手性和拓扑特征，并为探索手性和量子热力学之间的关系铺平道路。