Abstract

In this talk I will discuss the dynamics of a resonator coupled to a mesoscopic conductor known as a superconducting single electron transistor (SSET). The SSET supports a number of current resonances which can alter the dynamics of the resonator significantly and in a way which depends very sensitively on the precise choice of operating point for the transistor. For bias points on one side of a current resonance (red de-tuning), the SSET acts on the resonator like a thermal bath with a very low effective temperature which under certain circumstances can actually be used to cool the resonator. In contrast, for bias points on the opposite side of a resonance (blue de-tuning) the SSET can drive the resonator into laser-like states of self-sustained oscillation. Recent experiments have realized this system with two very different types of resonator, namely a mechanical resonator consisting of a suspended beam with a fundamental frequency of 20MHz [Naik et al., Nature 443, 193 (2006)] and a superconducting strip-line resonator with a frequency of 10GHz [Astafiev et al., Nature 449, 588].