Title: Quantum and thermal noise in optomechanical systems
Abstract: Recently there has been much experimental progress in understanding the interaction of light with solid state mechanical resonators at the quantum level in systems ranging from nano-optomechanical systems to large-scale interferometric gravitational wave observatories. I will begin by reviewing the basics of quantum noise limits of optical detection of mechanical motion, which are mostly captured by Heisenberg's-Microscope-like uncertainty trade offs. I will highlight the central role of correlations in quantum noise introduced by the optomechanical interactions by discussing their manifestations in recent nano/micro-optomechanics experiments: For example the spectrum of light produced when a mechanical resonator comes to a thermal equilibrium with the optical force noise bath of the vacuum fluctuations of an optical cavity mode. I will discuss a recent experiment where we measure the extremely weak signature of Heisenberg measurement backaction in the form of optical quantum correlations on light probing a nanomechanical resonator, even while the mechanics is strongly coupled to the ambient environment -- room temperature and atmospheric pressure [1]. We use the scale of these quantum correlations relative to the measured thermal motion to absolutely calibrate the resonator temperature, demonstrating a route toward an on-chip primary thermometry referenced to fundamental constants. [1] T. P. Purdy, K. E. Grutter, K. Srinivasan, J. M. Taylor, Science 356, 1265 (2017).