Early Stage Researcher 8, ETH, SWITZERLAND

 

Project title and work package:

Mesoscopic thermodynamics with semiconductor quantum dots, work package Quantum thermodynamics

 

Objectives:

You will exploit the unique tuneability of semiconductor quantum dots in order to investigate charge transport and charge fluctuations on the level of individual electrons. Recently it became possible to probe the Jarzynski relation (relating free energy differences and the irreversible work along an ensemble of trajectories) both for superconducting structures (AALTO) as well as for semiconductor quantum dots (ETH). The next step is to demonstrate that quantum dots can be driven out of equilibrium in order to measure transition of events that rarely occur in equilibrium because of occupation probabilities being so low. You will develop gate-pulsing and read-out schemes in order to extract tunnelling rates out of equilibrium, but also to determine entropy production and heat dissipation in contacts as well as in coupled quantum devices themselves. You will further attempt to realise a Maxwell's demon situation by carefully tuning the input energies and measuring the dissipated energy when electrons escape to the leads. These experiments will be done in close collaboration with Early Stage Researcher 5 (AALTO, Finland, the pioneer in this field) and theoretically analysed in collaboration with Early Stage Researcher 7 (UKON, Germany).

Previous work in this domain could be mostly understood in terms of single-particle tunnelling rates. In this project, you will extend the experimental study in order to incorporate and understand effects such as level degeneracies (because of spin and orbit) as well as interaction effects that can modify single-particle energies and transition rates. This will be relevant for the understanding of thermodynamics of mesoscopic devices in general. In addition, you will explore fluctuations in coherently coupled quantum dots in order to understand quantum effects with this unique experimental approach.

 

Expected Results:

- Transport through quantum dots driven out of equilibrium.

- Measurement of tunnelling rates and level degeneracies for few electron single and double quantum dots.

- Determination of dissipated heat and energy intake of the quantum system, relation to thermodynamic relations.

 

Planned secondments:

at ATTO, Germany (2 months, Year 1) for training in measurement techniques for out-of-equilibrium measurements, at AALTO, Finland (1 month, Year 2) to learn cooling techniques using superconducting structures, at NGU, Spain (1 month, Year 3) for training in molecular electronics.

 

RESEARCHER IN CHARGE:

ensslin@phys.ethz.ch

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