Josephson junctions (JJs) and their tunable properties, including their nonlinearities, play an important role in superconducting qubits and amplifiers. JJs together with the circuit quantum electrodynamics architecture form many key components of quantum information processing¹. In quantum circuits, low-noise amplification of feeble microwave signals is essential, and Josephson parametric amplifiers (JPAs)² are the widely used devices. The existing JPAs are based on Al–AlO_x–Al tunnel junctions realized in a superconducting quantum interference device geometry, where magnetic flux is the knob for tuning the frequency. Recent experimental realizations of two-dimensional (2D) van der Waals JJs^3,4,5 provide an opportunity to implement various circuit quantum electrodynamics devices^6,7,8 with the added advantage of tuning the junction properties and the operating point using a gate potential. While other components of a possible 2D van der Waals circuit quantum electrodynamics architecture have been demonstrated, a quantum-noise-limited amplifier, an essential component, has not been realized, to the best of our knowledge. Here we implement a quantum-noise-limited JPA using a graphene JJ, that has a linear resonance gate tunability of 3.5 GHz. We report 24 dB amplification with 10 MHz bandwidth and −130 dBm saturation power, a performance on par with the best single-junction JPAs^2,9. Importantly, our gate-tunable JPA works in the quantum-limited noise regime, which makes it an attractive option for highly sensitive signal processing. Our work has implications for novel bolometers; the low heat capacity of graphene together with JJ nonlinearity can result in an extremely sensitive microwave bolometer embedded inside a quantum-noise-limited amplifier. In general, this work will open up the exploration of scalable device architectures of 2D van der Waals materials by integrating a sensor with the quantum amplifier.

约瑟夫森结 (JJ) 及其可调特性（包括非线性）在超导量子比特和放大器中发挥着重要作用。JJ 与电路量子电动力学架构一起构成了量子信息处理¹的许多关键组件。在量子电路中，微弱微波信号的低噪声放大是必不可少的，约瑟夫森参量放大器 (JPA) ²是广泛使用的器件。现有的 JPA 基于在超导量子干涉装置几何结构中实现的 Al-AlOx- Al 隧道结，_其中磁通量是调谐频率的旋钮。二维 (2D) van der Waals JJs ^{3,4,5的最新实验实现}提供了实现各种电路量子电动力学设备^6,7,8的机会，并具有使用栅极电位调整结特性和工作点的附加优势。虽然已经证明了可能的 2D 范德瓦尔斯电路量子电动力学架构的其他组件，但据我们所知，量子噪声限制放大器是一个重要组件，尚未实现。在这里，我们使用石墨烯 JJ 实现了一个量子噪声限制的 JPA，它具有 3.5 GHz 的线性共振门可调性。我们报告了具有 10 MHz 带宽和 −130 dBm 饱和功率的 24 dB 放大，性能与最佳单结 JPA 相当^2,9. 重要的是，我们的门可调 JPA 在量子限制噪声范围内工作，这使其成为高度敏感信号处理的有吸引力的选择。我们的工作对新型测辐射热计有影响；石墨烯的低热容量和 JJ 非线性可以导致嵌入量子噪声限制放大器内的极其灵敏的微波测辐射热计。总的来说，这项工作将通过将传感器与量子放大器集成在一起，开启对二维范德瓦尔斯材料可扩展设备架构的探索。