Implementations: from classical to quantum thermodynamic experiments
Given the generality of classical thermodynamic principles and their importance for engineering in the macroscopic world, it is of utmost importance to address the corresponding phenomena in various quantum realizations of modern experimental systems.
It is now that advances in producing and controlling a range of different man-made quantum systems is starting to provide ideal experimental techniques to test and explore thermodynamics and energy statistics in the quantum regime. Experimenters in mesoscopic electron systems, cold atoms, trapped ions and quantum optics, all share the common interest of understanding relaxation, thermalisation, non-equilibrium and general thermodynamic properties of their systems. WG3 will aim to reconcile quantum information and thermodynamic techniques to test and explore thermodynamic and non-equilibrium relations at the classical-quantum boundary and into the quantum regime.
Current state of knowledge
Recent advances in producing and controlling man-made quantum systems provide a gateway to understanding thermodynamics in the quantum regime. Such devices include mesoscopic electron systems, cold trapped atoms, ions and nanoscale oscillators. The mesoscopic electron transport community has a relatively long history of research on energy relaxation and non-equilibrium phenomena, see WG1, due to the needs in, e.g., sensor applications and active cooling. Experiments are typically performed under biased conditions and overheating due to simple Joule power is inevitable. Relevant to the theoretical work in WG2, the validity of classical fluctuation theorems has been demonstrated successfully in the last decade in a number of experiments involving e.g. biomolecular, mechanical or colloidal systems. By contrast, no quantum experiment has been performed so far due to the inherent difficulties of defining and measuring heat and work in a quantum setting. In 2011, a major step in the miniaturization of heat engines has been taken with the physical implementation of two microengines, a piezoresistive and a colloidal Stirling motor. Their performances are in agreement with the predictions of the stochastic extension of classical thermodynamics. However, although extensively studied theoretically in the last 50 years, no quantum heat engine has been built to date.
Goals of the Working Group
The main research task is to discuss implementations of thermodynamic experiments and realise them, not only in the classical regime but also aiming at true quantum implementations. Several types of thermodynamic experiments have been performed, for instance refrigeration and heat transport in solid state electronic circuits, where the systems are quantum mechanical as such (e.g. superconductors), but the phenomena themselves have not been directly influenced by “secondary” quantum effects via quantum conjugate variables.
This Action aims at achieving this challenge by involving theorists and experimenters with different systems to address the following tasks:
- Experimentally observe equilibration and thermalisation in quantum systems and provide a detailed study of a multitude of different relevant physical situations.
- Realise microscopically small engines and push towards the quantum limit.
- Observing non-equilibrium dynamics in the quantum regime and testing non-equilibrium relations, i.e. fluctuation relations. Use feedback mechanisms to observe changes to thermodynamic properties and laws.