Malnou M, Aumentado J, Vissers M R, Wheeler J D, Hubmayr J, Ullom J N, Gao J
National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
Phys Rev Appl. 2022 Apr;17(4). doi: 10.1103/physrevapplied.17.044009.
Most microwave readout architectures in quantum computing or sensing rely on a semiconductor amplifier at 4 K, typically a high-electron mobility transistor (HEMT). Despite its remarkable noise performance, a conventional HEMT dissipates several milliwatts of power, posing a practical challenge to scale up the number of qubits or sensors addressed in these architectures. As an alternative, we present an amplification chain consisting of a kinetic inductance traveling-wave parametric amplifier (KITWPA) placed at 4 K, followed by a HEMT placed at 70 K, and demonstrate a chain-added noise between 3.5 and 5.5 GHz. While, in principle, any parametric amplifier can be quantum limited even at 4 K, in practice we find the performance of the KITWPA to be limited by the temperature of its inputs and by an excess of noise . The dissipation of the rf pump of the KITWPA constitutes the main power load at 4 K and is about 1% that of a HEMT. These combined noise and power dissipation values pave the way for the use of the KITWPA as a replacement for semiconductor amplifiers.
量子计算或传感中的大多数微波读出架构都依赖于4K温度下的半导体放大器，通常是高电子迁移率晶体管（HEMT）。尽管传统的HEMT具有出色的噪声性能，但它会消耗几毫瓦的功率，这对扩大这些架构中所涉及的量子比特或传感器的数量构成了实际挑战。作为替代方案，我们提出了一种放大链，它由放置在4K温度下的动态电感行波参量放大器（KITWPA）和放置在70K温度下的HEMT组成，并展示了在3.5至5.5GHz之间的链加噪声。虽然原则上任何参量放大器即使在4K温度下也可以达到量子极限，但实际上我们发现KITWPA的性能受到其输入温度和过量噪声的限制。KITWPA的射频泵浦损耗是4K温度下的主要功率负载，约为HEMT的1%。这些综合的噪声和功耗值为使用KITWPA替代半导体放大器铺平了道路。
