Early Stage Researcher 7, UKON, GERMANY


Project title and work package:

Theory of time-dependent heat transport and detection of fluctuations, work package Quantum thermodynamics



You will investigate quantum thermodynamic transport realised in superconducting circuits.

Pumping heat: You will first develop the concept of an energy pump in a mesoscopic superconductor-normal metal heterostructure. Using the phase sensitivity in Andreev interferometers, you will study the electronic and radiative transport of heat driven by a time-dependent flux. Using the Keldysh Green function method, you will describe the pumping of heat and charge from adiabatic to non-adiabatic driving in collaboration with Early Stage Researcher 3 (CNRS, France). You will address the full transport statistics and relate it to fundamental thermodynamics concepts like entropy production. This discussion will have an impact on the experimental control of heat and charge transport in mesoscopic current standards as well as on tests of fundamental fluctuation relations in connection with the projects of Early Stage Researcher 4 (AALTO, Finland) and Early Stage Researcher 8 (ETH, Switzerland).

Measuring fluctuations of heat using superconducting threshold detectors: The detection of fluctuations in the quantum regime is a fundamental challenge. On the theoretical side, one has to consider detection schemes in the weak, non-invasive limit to access correlations without disturbance. To develop a heat detection device, you will investigate a superconducting tunnel junction acting as a heat fluctuation filter. Embedded in an electromagnetic environment, radiative heat transfer will be taken into account. You will investigate the possibility of using superconducting single electron devices showing a pronounced even-odd effect as heat detector (relevant for Early Stage Researchers 1, 2 (CNRS France), and 6 UKON, Germany)). The goal will be to propose a three-terminal device as realisation of a Maxwell demon, by operating an SSS or NSN SET far from equilibrium.


Expected Results:

- Concept of an energy pump in a mesoscopic superconductor heterostructure.

- Quantitative description of the full transport characteristics of heat and charge (electronic and radiative).

- Characteristics of a SSS or NSN SET realizing a Maxwell demon and testing basic concepts of quantum thermodynamics.


Planned secondments:

at AALTO, Finland (1 month, Year 1) learning basics of the theory of refrigeration in mesoscopic devices, at CNRS, France (2 months, Year 2) to learn theoretical techniques of quantum tunnelling in superconducting junctions, at EDP Sciences, France (2 months, Year 3) to get trained in scientific writing and editing.




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