Pirkkalainen J-M, Cho S U, Massel F, Tuorila J, Heikkilä T T, Hakonen P J, Sillanpää M A
Department of Applied Physics, Aalto University, PO Box 11100, FI-00076 Aalto, Finland.
Department of Applied Physics, Low Temperature Laboratory, Aalto University, PO Box 15100, FI-00076 Aalto, Finland.
Nat Commun. 2015 Apr 27;6:6981. doi: 10.1038/ncomms7981.
Coupling electromagnetic waves in a cavity and mechanical vibrations via the radiation pressure of photons is a promising platform for investigations of quantum-mechanical properties of motion. A drawback is that the effect of one photon tends to be tiny, and hence one of the pressing challenges is to substantially increase the interaction strength. A novel scenario is to introduce into the setup a quantum two-level system (qubit), which, besides strengthening the coupling, allows for rich physics via strongly enhanced nonlinearities. Here we present a design of cavity optomechanics in the microwave frequency regime involving a Josephson junction qubit. We demonstrate boosting of the radiation-pressure interaction by six orders of magnitude, allowing to approach the strong coupling regime. We observe nonlinear phenomena at single-photon energies, such as an enhanced damping attributed to the qubit. This work opens up nonlinear cavity optomechanics as a plausible tool for the study of quantum properties of motion.
通过光子的辐射压力将腔内的电磁波与机械振动耦合起来，是研究运动量子力学特性的一个很有前景的平台。一个缺点是单个光子的效应往往很小，因此一个紧迫的挑战是大幅提高相互作用强度。一种新颖的方案是在装置中引入一个量子二能级系统（量子比特），这除了增强耦合外，还能通过大幅增强的非线性实现丰富的物理现象。在此，我们展示了一种在微波频率范围涉及约瑟夫森结量子比特的腔光力学设计。我们证明了辐射压力相互作用增强了六个数量级，使得能够接近强耦合 regime。我们在单光子能量下观测到非线性现象，比如归因于量子比特的增强阻尼。这项工作开启了非线性腔光力学作为研究运动量子特性的一种可行工具的大门。
