Interactions are essential for the creation of correlated quantum many-body states. Although two-body interactions underlie most natural phenomena, three- and four-body interactions are important for the physics of nuclei¹, exotic few-body states in ultracold quantum gases², the fractional quantum Hall effect³, quantum error correction⁴ and holography^5,6. Recently, a number of artificial quantum systems have emerged as simulators for many-body physics, featuring the ability to engineer strong interactions. However, the interactions in these systems have largely been limited to the two-body paradigm and require building up multibody interactions by combining two-body forces. Here we implement a scheme to create a higher-order interaction between photons stored in multiple electromagnetic modes of a microwave cavity. The system is dressed such that there is collectively no interaction until a target total photon number is reached across multiple distinct modes, at which point the photons interact strongly. In our demonstration, we create interactions involving up to three bodies and across up to five modes. We harness the interaction to prepare single-mode Fock states and multimode W states, which we verify by introducing a multimode Wigner tomography method.

相互作用对于创建相关的量子多体状态至关重要。尽管二体相互作用是大多数自然现象的基础，但三体和四体相互作用对于原子核物理¹、超冷量子气体中的奇异少体态²、分数量子霍尔效应³、量子纠错⁴和全息很重要^5,6. 最近，许多人工量子系统已经成为多体物理的模拟器，具有设计强相互作用的能力。然而，这些系统中的相互作用在很大程度上仅限于两体范式，需要通过结合两体力来建立多体相互作用。在这里，我们实施了一个方案来创建存储在微波腔的多个电磁模式中的光子之间的高阶相互作用。该系统经过修饰，使得在跨越多个不同模式达到目标总光子数之前集体没有相互作用，此时光子会强烈相互作用。在我们的演示中，我们创建了涉及多达三个主体和多达五种模式的交互。我们利用交互来准备单模 Fock 状态和多模 W 状态，