Thermo Dynamics of Ion Coulomb Crystals

激光冷却离子库仑晶体是多体物理模拟中最有前途的平台之一。而过去的工作在库仑系统主要集中在纯和谐波系统的热力学平衡，最近的注意力已经转移到非平衡动力学和非线性，不可积模型的研究。最近的一个挑战是理解低维量子系统中的热输运，因为凝聚态系统正在进入纳米级范围，但微观参数不能很好地控制，并且热力学量（如热流）在实验上无法获得。特别是，非线性可以导致各种有趣的影响，在热传输，如热整流器，不能分析访问。这个计画将使用离子库仑晶体作为一个良好控制的实验台，来研究量子系统中热力学的开始。我们将研究杂质和拓扑缺陷对低维晶体热输运的影响。在第一步中，我们将开发光谱技术来研究振动激发的传输和离子与恒温器的耦合。我们将证明傅立叶定律在低维线性晶体中的失效，并研究耗散和不均匀性的影响。第二步，我们将在库仑晶体中掺杂杂质和拓扑缺陷，并测量空间声子分布。在离子中加入噪音应该可以观察到噪音辅助的热传输。从长远来看，复杂晶体的热化，接近结构相变和强非线性存在将光谱分析。将振动模式引入量子区域，从导电相到隔离相的相变和纳米摩擦的研究将变得容易。

Laser-cooled ion Coulomb crystals are representing one of the most promising platforms for the simulation of many-body physics. Whereas past work in Coulomb systems was mainly focused on pure and harmonic systems in thermo-dynamic equilibrium, recent attention has shifted to the study of non-equilibrium dynamics and nonlinear, non-integrable models. A recent challenge is the understanding of heat transport in low-dimensional quantum systems, as condensed matter systems are entering the nanoscale regime, but microscopic parameters cannot be well-controlled and thermodynamic quantities such as heat current are experimentally not accessible. In particular, nonlinearities can lead to a variety of intriguing effects in thermal transport, such as thermal rectifiers, that cannot be analytically accessed. This project will use ion Coulomb crystals as a well-controlled test bed to study the onset of thermodynamics in quantum systems. We will investigate the effect of impurities and topological defects on the heat transport of low-dimensional crystals. In a first step, we will develop spectroscopic techniques to study the transport of vibrational excitations and the coupling of the ions to thermostats. We will demonstrate the breakdown of Fouriers law in low-dimensional linear crystals and study the influence of dissipation and inhomogeneity. In a second step, we will dope the Coulomb crystal with impurities and topological defects and measure the spatial phonon distribution. Adding noise to the ions should allow observing noise-assisted heat transport. In the long term, the thermalization of complex crystals, close to structural phase transitions and with strong nonlinearities present will be spectroscopically analyzed. Bringing the vibrational modes to the quantum regime, phase transitions from conducting to isolating phases and the study of nanofriction will become accessible.