论文标题

使用石墨烯约瑟夫森连接的量子噪声有限的微波放大

Quantum noise limited microwave amplification using a graphene Josephson junction

论文作者

Sarkar, Joydip, Salunkhe, Kishor V., Mandal, Supriya, Ghatak, Subhamoy, Marchawala, Alisha H., Das, Ipsita, Watanabe, Kenji, Taniguchi, Takashi, Vijay, R., Deshmukh, Mandar M.

论文摘要

约瑟夫森连接(JJ)及其可调特性(包括其非线性)构成了超导电路量子电动力学(CQED)的核心。在量子电路中,微弱的微波信号的低噪声放大至关重要,而约瑟夫森参数放大器(JPA)是广泛使用的设备。现有的JPA基于在超导量子干扰装置几何形状中实现的Al-Alox-Al隧道连接,其中磁通量是调谐频率的旋钮。 2D van der waals JJS的最新实验实现为实施各种CQED设备提供了机会,其额外优势是使用门电位调整连接属性和操作点。虽然已经证明了可能的2D范德华CQED结构的其他组件,但尚未实现量子噪声限制放大器(量子噪声)的放大器。在这里,我们使用石墨烯JJ实现了量子噪声有限的JPA,其线性共振门可调性为3.5 GHz。我们报告了24 dB扩增,具有10 MHz带宽和-130 dBM饱和功率;与最佳单连接JPA的表现相当。重要的是,我们的门可调JPA在量子限制的噪声状态下工作,这使其成为高度敏感的信号处理的有吸引力的选择。我们的工作对新型强仪有影响 - 石墨烯与JJ非线性的低热量能力可能导致嵌入量子噪声限制的放大器中的极敏感的微波炉仪。通常,我们的工作将通过将传感器与量子放大器集成,对2D Van der Waals材料的可扩展设备架构进行探索。

Josephson junctions (JJ) and their tunable properties, including their nonlinearities, form the core of superconducting circuit quantum electrodynamics (cQED). In quantum circuits, low-noise amplification of feeble microwave signals is essential and the Josephson parametric amplifiers (JPA) are the widely used devices. The existing JPAs are based on Al-AlOx-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 2D van der Waals JJs provide an opportunity to implement various cQED devices 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 cQED architecture have been demonstrated -- quantum noise limited amplifier, an essential component, has not been realized. Here we implement a quantum noise limited JPA, using a graphene JJ, that has linear resonance gate tunability of 3.5 GHz. We report 24 dB amplification with 10 MHz bandwidth and -130 dBm saturation power; performance on par with the best single-junction JPAs. 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, our work will open up exploration of scalable device architecture of 2D van der Waals materials by integrating a sensor with the quantum amplifier.

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