Mechanical dissipation and phonon-induced decoherence in nanomechanical and optomechanical systems

最先进的光学和纳米机械装置接近于允许在“宏观”机械系统中观察量子效应。这将进一步研究量子物理学中的基础问题，并为技术应用提供有希望的替代方案，例如在单自旋水平上检测磁化。在这方面的一个主要挑战是了解和控制这些系统中的机械耗散。这特别适用于“原子大小”的纳米机械结构，如碳纳米管，它们正成为通过电学和光学手段对局部电子自由度进行相干控制的理想候选者。在这种低维固态系统中的一个基本问题是声子诱导的退相干如何限制它们的性能。本计画将探讨目前尚未解决的问题，包括奈米结构中的机械耗散与声子诱导的退相干。具体来说，我们将研究应力的作用，在内部耗散的纳米机械谐振器和声子约束的作用，在消相干的嵌入式两级光子发射器使用扩展的自旋玻色子模型。

State of the art opto- and nano-mechanical setups are close to allowing for the observation of quantum effects in a ‘macroscopic’ mechanical system. This will both, further the investigation of foundational issues in quantum physics and provide promising alternatives for technological applications, for instance in the detection of magnetization at the single spin level. A major challenge in this context is to understand and control mechanical dissipation in these systems. This applies, in particular, to ‘atomic-sized’ nanomechanical structures such as carbon nanotubes, which are emerging as ideal candidates for the coherent control of localized electronic degrees of freedom by electrical and optical means. A fundamental issue in such low dimensional solid-state systems is how phonon-induced decoherence limits their performance. This project will address current open problems concerning the mechanical dissipation and phonon-induced decoherence in suspended nanostructures. Specifically, we will study the role of stress in the internal dissipation of nanomechanical resonators and the role of phonon confinement in the decoherence of embedded two-level photon emitters using an extended spin-boson model.