With a large portfolio of elemental quantum components, superconducting quantum circuits have contributed to advances in microwave quantum optics¹. Of these elements, quantum-limited parametric amplifiers^2,3,4 are essential for low noise readout of quantum systems whose energy range is intrinsically low (tens of μeV)^5,6. They are also used to generate non-classical states of light that can be a resource for quantum enhanced detection⁷. Superconducting parametric amplifiers, such as quantum bits, typically use a Josephson junction as a source of magnetically tunable and dissipation-free non-linearity. In recent years, efforts have been made to introduce semiconductor weak links as electrically tunable non-linear elements, with demonstrations of microwave resonators and quantum bits using semiconductor nanowires^8,9, a two-dimensional electron gas¹⁰, carbon nanotubes¹¹ and graphene^12,13. However, given the challenge of balancing non-linearity, dissipation, participation and energy scale, parametric amplifiers have not yet been implemented with a semiconductor weak link. Here, we demonstrate a parametric amplifier leveraging a graphene Josephson junction and show that its working frequency is widely tunable with a gate voltage. We report gain exceeding 20 dB and noise performance close to the standard quantum limit. Our results expand the toolset for electrically tunable superconducting quantum circuits. They also offer opportunities for the development of quantum technologies such as quantum computing, quantum sensing and for fundamental science¹⁴.

凭借大量的元素量子组件，超导量子电路为微波量子光学¹的进步做出了贡献。在这些元素中，量子限制参数放大器^2,3,4对于能量范围本质上很低（数十 μeV）^5,6的量子系统的低噪声读出至关重要。它们还用于生成非经典光态，可作为量子增强检测的资源⁷. 超导参量放大器，例如量子比特，通常使用约瑟夫森结作为磁可调和无耗散非线性源。近年来，已努力将半导体薄弱环节引入为电可调非线性元件，并使用半导体纳米线^8,9、二维电子气¹⁰、碳纳米管¹¹和石墨烯^{12演示了微波谐振器和量子比特,13}. 然而，考虑到平衡非线性、耗散、参与和能量标度的挑战，参数放大器还没有用半导体薄弱环节来实现。在这里，我们展示了一个利用石墨烯约瑟夫森结的参量放大器，并表明其工作频率可通过栅极电压广泛调节。我们报告增益超过 20 dB，噪声性能接近标准量子极限。我们的结果扩展了电可调超导量子电路的工具集。它们还为量子计算、量子传感等量子技术的发展和基础科学¹⁴提供了机会。