In this article, we present a nanoelectromechanical system (NEMS) designed to detect changes in the Casimir energy. The Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic vacuum. Previous experiments have used nano- or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two surfaces. In this new set of experiments, we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates, one of which is a superconductor. A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature (T_c) because of the interaction between it and the superconducting condensation energy. In our experiment, we take a superconducting film, carefully measure its transition temperature, bring a conducting plate close to the film, create a Casimir cavity, and then measure the transition temperature again. The expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures, so using a NEMS resonator in situ is the only practical way to obtain accurate, reproducible data. Using a thin Pb film and opposing Au surface, we observe no shift in T_c >12 µK down to a minimum spacing of ~70 nm at zero applied magnetic field.

在本文中，我们提出了一种纳米机电系统（NEMS），旨在检测卡西米尔能量的变化。卡西米尔效应是电磁真空中量子涨落出现的结果。先前的实验使用纳米或微米级平行板电容器通过测量这些波动在两个表面之间施加的小吸引力来检测卡西米尔力。在这组新的实验中，我们的目标是直接检测真空中由于金属平行板（其中一个是超导体）的存在而引起的卡西米尔能量的变化。由于卡西米尔能量与超导凝聚能量之间的相互作用，预计该结构的卡西米尔能量的变化会改变超导转变温度（ T _c ）。在我们的实验中，我们采用超导薄膜，仔细测量其转变温度，将导电板靠近薄膜，创建卡西米尔腔，然后再次测量转变温度。预期的位移小于超导薄膜循环到低温时看到的正常位移，因此原位使用 NEMS 谐振器是获得准确、可重复数据的唯一实用方法。使用薄的 Pb 薄膜和相对的 Au 表面，我们观察到在零外加磁场下T _c >12 µK 的最小间距没有变化到约 70 nm。