Thermo Dynamics of Ion Coulomb Crystals

• Applicant: Professorin Dr. Tanja E. Mehlstäubler
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 265861437

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.

• DFG Programme: Research Grants