标题： 微波和机械谐振器中热涨落的研究 显示英文标题

标题： The Study of Thermal Fluctuations in Microwave and Mechanical Resonators

摘要： 我们报告了使用双通道读出系统对微波和机械谐振器中热涨落的高分辨率测量。后者包括一个低噪声放大器、一个I/Q混频器和一个交叉相关器。我们发现，在某些条件下，低噪声放大器的固有涨落（对读出系统的两个通道都是共有的）在计算混频器输出之间的电压噪声交叉谱时会被平均掉。放大器的技术涨落的抑制显著提高了谐振器所表现出的热噪声峰的对比度。因此，对于室温稳定的9 GHz蓝宝石加载腔谐振器，与单通道测量相比，我们观察到了超过16 dB的热噪声峰对比度改善。双通道读出系统区分宽带和窄带涨落的能力可能有助于寻找暗物质，这依赖于低温微波谐振器的使用。 显示英文摘要

摘要： We report high-resolution measurements of thermal fluctuations in microwave and mechanical resonators using a dual-channel readout system. The latter comprises a low-noise amplifier, an I/Q-mixer, and a cross-correlator. We discovered that, under certain conditions, the intrinsic fluctuations of the low-noise amplifier, which are common to both channels of the readout system, are averaged out when computing the voltage noise cross-spectrum between the mixer's outputs. The suppression of the amplifier's technical fluctuations significantly improves the contrast of the thermal noise peaks exhibited by the resonators. Thus, for the room-temperature-stabilized 9 GHz sapphire-loaded cavity resonator, we observed more than 16 dB improvement in the thermal noise peak contrast relative to the single-channel measurements. The ability of the dual-channel readout system to discriminate between the broad- and narrow-band fluctuations may benefit the search for dark matter, which relies on the use of cryogenic microwave resonators.