Quantum effects in thermodynamics: Exploring the limitations and the potential for applications

• Applicant: Dr. Rodrigo Gallego
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas ; Theoretical Condensed Matter Physics
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 287022405

Thermodynamics is a tremendously powerful theory, applicable to essentially all branches of classical physics. Nonetheless, the understanding of thermodynamical processes at the nano-scale, where quantum effects come into play, is still limited. Recent years have seen an enormous revival of interest in the study of such processes in the quantum regime, in the rapid ongoing development of quantum thermodynamics. This has been triggered, on the experimental side, by developments in the context of opto-mechanics and mesoscopic systems; and on the theoretical side, by bringing into play notions of quantum information theory, with entanglement and information taking center stage. Some first steps have been taken by identifying the ultimate bounds on thermodynamical tasks performed with quantum systems, which constitute the quantum analogues of the laws of thermodynamics. However, much less emphasis has been put in incorporating the limitations that emerge as an unavoidable consequence of dealing with quantum systems. This step is crucial in order to bring the fresh theoretical insights into contact with state of the art technology capable of handling individual quantum systems.In this research project, I contribute to fill this substantial gap by investigating a set of concrete questions that arise when confronting, on the one hand, advantageous features that quantum systems provide over its classical counterpart, with, on the other, the distinctive limitations on the manipulation and quantification of quantum resources. Specifically, I will ask: i) how to quantify the performance of thermal machines operating with individual quantum systems? ii) how to incorporate a realistic treatment of heat baths in the quantum regime? iii) what are the precise limitations that emerge when confronting quantum thermodynamics with locality in interacting many-body systems, ubiquitous in the condensed matter context? These questions, designed to bring quantum thermodynamics closer to practical regimes, will also interplay significantly with the foundations of quantum theory. The quantification of tasks under limitations is intimately related with quantum resource theories. In particular, locality-constraints are deeply connected with notions of entanglement, information processing and quantum computation. Hence, these questions are likely to bridge the field not only with experiments, but also with other fields of quantum physics. The project will be performed bringing together tools from quantum information and many-body physics, on which I have developed accredited expertise by significantly contributing to resource theories of entanglement and non-locality, and also to approaches to thermal machines and work and heat quantification. Such results constitute the first steps in answering question i-iii), which enable me to pose concrete open problems, on which my collaborators at the home institution and myself would be able to jump immediately.

• DFG Programme: Research Grants