Quantum violations of Thermodynamic Uncertainty Relations in Strongly Coupled Open Quantum Systems

Project Information

QuTUR

Grant agreement ID: 101104590

DOI

10.3030/101104590

Project closed

EC signature date 31 March 2023

Start date 1 July 2023

End date 30 June 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 222 727,68

Coordinated by

LUNDS UNIVERSITET
Sweden

Periodic Reporting for period 1 - QuTUR (Quantum violations of Thermodynamic Uncertainty Relations in Strongly Coupled Open Quantum Systems)

Reporting period: 2023-07-01 to 2025-06-30

Summary of the context and overall objectives of the project

In stochastic thermodynamics, thermodynamic uncertainty relations (TURs) fundamentally connect the efficiency, power output and reliability of any classical heat engine. These TURs imply that any efficient heat engine operating at finite power output must suffer from large fluctuations in the power output, making the engine unreliable. However, these TURs can be broken in quantum heat engines, allowing them to achieve a quantum thermodynamic advantage regarding their output precision with obvious implications for nano-scale applications.

The overall objective of this project was to theoretically analyze noise in quantum dots in general, and TURs in quantum dot heat engines in particular, aiming to establish a clear understanding for the conditions required to break TURs. This project aimed at directly addressing the theoretically complicated but experimentally realistic parameter regime of both strong tunnel-coupling and strong Coulomb interaction. This is possible because of a new thermodynamic renormalization group method recently developed by the fellow.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The main achievement of this project was to include calculations of noise into a thermodynamic renormalization group method recently developed by the fellow. This method treats interactions within the quantum dot system exactly, and effectively resums contributions to all orders in the tunnel couplings between the quantum dot system and the environment. This allows treating the experimentally important but theoretically notoriously difficult regime of large interactions and large tunnel couplings. Extending this theory to include calculations of noise was highly nontrivial and required deriving a set of new diagrammatic rules. A general numerical implementation of the developed theory was also achieved.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

This project has developed new theoretical methods that go beyond the state-of-the-art and that allows calculating both the current and noise through quantum dot systems that have both strong local electron-electron interactions and strong tunnel coupling to metallic electrodes. This allows the investigation of, for example, noise in strongly correlated systems and thermodynamic uncertainty relations.