## RELATIVISTIC AND QUANTUM THERMODYNAMICS

*About thermodynamics*: Thermodynamics is arguably the most long lived and successfully exploited theory of all physical theories. It can be used to understand the physics and performance of heat machines, to study black holes and condensed matter systems, to investigate properties of the cosmos. It has been so successful that it has barely changed in the past two hundred years. However, a fundamental aspect of thermodynamics is that it applies to systems that are composed of (very) large amounts of constituents. A gas, like the air in a bottle, is a good example of a system which can be studied with thermodynamics to (extremely) good approximation.

A very basic question naturally arises: can thermodynamics can be exported to single (and small) systems?

The answer is

**yes**, and many new features arise.

This has led many scientists to work in the area pf physics loosely named quantum thermodynamics. The aim is to understand how to extend concepts such as heat, work and temperature to systems with one or few constituents.

I have recently applied state of the art tools from quantum thermodynamics to relativistic fields, such as bosons and fermions. The results are very interesting because it is still not well understood what is the interplay between relativity, quantum correlations, energy and entropy. One can show that quantum correlations come at a cost, and we try to understand how this cost depends on the relativistic nature of the fundamental constituents of our universe.

Together with my collaborators, I found the ultimate bound on how many correlations can be created given a fixed amount of work that can be used in a unitary process. This will help me develop more the quantum thermodynamics of relativistic systems.

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