Quantum fluids exhibit quantum mechanical effects at the macroscopic level, which contrast strongly with classical fluids. Gain-dissipative solid-state exciton-polaritons systems are promising emulation platforms for complex quantum fluid studies at elevated temperatures. Recently, halide perovskite polariton systems have emerged as materials with distinctive advantages over other room-temperature systems for future studies of topological physics, non-Abelian gauge fields, and spin-orbit interactions. However, the demonstration of nonlinear quantum hydrodynamics, such as superfluidity and Čerenkov flow, which is a consequence of the renormalized elementary excitation spectrum, remains elusive in halide perovskites. Here, using homogenous halide perovskites single crystals, we report, in both one- and two-dimensional cases, the complete set of quantum fluid phase transitions from normal classical fluids to scatterless polariton superfluids and supersonic fluids—all at room temperature, clear consequences of the Landau criterion. Specifically, the supersonic Čerenkov wave pattern was observed at room temperature. The experimental results are also in quantitative agreement with theoretical predictions from the dissipative Gross-Pitaevskii equation. Our results set the stage for exploring the rich non-equilibrium quantum fluid many-body physics at room temperature and also pave the way for important polaritonic device applications.

量子流体在宏观层面表现出量子力学效应，这与经典流体形成鲜明对比。增益耗散固态激子-极化激元系统是用于高温下复杂量子流体研究的有前途的仿真平台。最近，卤化物钙钛矿极化子系统已成为比其他室温系统具有独特优势的材料，可用于拓扑物理、非阿贝尔规范场和自旋轨道相互作用的未来研究。然而，非线性量子流体动力学的证明，例如超流和切伦科夫流，这是重整化元素激发光谱的结果，在卤化物钙钛矿中仍然难以捉摸。在这里，我们使用同质卤化物钙钛矿单晶，在一维和二维情况下，从普通经典流体到无散射极化子超流体和超音速流体的完整量子流体相变集——所有这些都在室温下进行，朗道准则的明确结果。具体而言，在室温下观察到超音速切伦科夫波模式。实验结果也与耗散 Gross-Pitaevskii 方程的理论预测定量一致。我们的结果为探索室温下丰富的非平衡量子流体多体物理奠定了基础，也为重要的极化器件应用铺平了道路。在室温下观察到超音速切伦科夫波型。实验结果也与耗散 Gross-Pitaevskii 方程的理论预测定量一致。我们的结果为探索室温下丰富的非平衡量子流体多体物理奠定了基础，也为重要的极化器件应用铺平了道路。在室温下观察到超音速切伦科夫波型。实验结果也与耗散 Gross-Pitaevskii 方程的理论预测定量一致。我们的结果为探索室温下丰富的非平衡量子流体多体物理奠定了基础，也为重要的极化器件应用铺平了道路。