论文标题
用匹配的温度变化噪声源表征低温放大器
Characterizing cryogenic amplifiers with a matched temperature-variable noise source
论文作者
论文摘要
我们提出了一个低温微波噪声源，其特征阻抗为50 $ω$，可以安装在低温恒温器的同轴线中。噪声源的浴温温度在0.1 K和5 K之间连续变化，而不会在样品空间上引起明显的反作用加热。作为概念验证实验，我们对包括波动波参数放大器和商业高电子迁移式晶体管放大器的放大器级联反应进行了Y因子测量。我们观察到系统噪声温度低至$ 680^{+20} _ { - 200} $ mk在5.7 GHz时，对应于$ 1.5^{+0.1} _ { - 0.7} $多余的光子。我们提出的系统在验证固态量子量读数线的验证中具有立即应用。
We present a cryogenic microwave noise source with a characteristic impedance of 50 $Ω$, which can be installed in a coaxial line of a cryostat. The bath temperature of the noise source is continuously variable between 0.1 K and 5 K without causing significant back-action heating on the sample space. As a proof-of-concept experiment, we perform Y-factor measurements of an amplifier cascade that includes a traveling wave parametric amplifier and a commercial high electron mobility transistor amplifier. We observe system noise temperatures as low as $680^{+20}_{-200}$ mK at 5.7 GHz corresponding to $1.5^{+0.1}_{-0.7}$ excess photons. The system we present has immediate applications in the validation of solid-state qubit readout lines.
