Experimental Realization of a Casimir Transistor: Switching and Amplifying Energy Transfer in a Three-Body Casimir System

The Casimir interaction can be used to couple two mechanical resonators and improve the quality factor of a mechanical resonator. While the Casimir effect between two objects has been extensively studied, the Casimir force between three objects is still unexplored. It is interesting to study the three-body interactions by quantum vacuum fluctuations. In this chapter, we will demonstrate the first observation of Casimir effects between three separate objects. A transistor-like energy transfer is realized in this three-channel Casimir system, which can switch and amplify the Casimir mediated energy transfer. We will first introduce the three-cantilever system. This is followed by the the measurement of Casimir force in this three-body system. Later on, we will present the observation of level repulsion in the three-body system due to Casimir coupling. The coupling and level repulsion can be well explained by an effective Hamiltonian that will also be discussed. In the last part of this chapter, we will show how we realize the transistor-like energy transfer in this three-object Casimir system. Parts of the contents in this chapter have been published in Xu et al. (Nat Commun 13(1):6148, 2022).