Overall, the research results achieved in WP1-3 have advanced the state of the art in the study of the thermodynamics of quantum measurement and quantum systems. These results, marked by high quality and interest, have been appropriately published in esteemed journals. The majority of the research involved international collaborations, facilitating the exchange of knowledge on various aspects of quantum thermodynamics between the host institution and international collaborators. Simultaneously, the host institution has particularly benefited from the researcher's expertise in quantum trajectories and quantum measurements, knowledge that has been successfully imparted to several PhD students.
1.2.1 Work Package 1
In WP1, the researcher alongside his collaborators, have developed a comprehensive tutorial manuscript covering the thermodynamics of quantum measurement in a tutorial format. This will ensure that the knowledge produced will be highly accessible to future researchers in the community. The results of this work have been highly praised and made a fundamental contribution to the field. This work was performed with collaborators from researchers at the host instution TCD, as well as researchers at Universität Basel, and the University of Rochester. The work has been published in Physical Review X Tutorial, but is also accessible freely at the arXiv:
M1. Current fluctuations in open quantum systems: Bridging the gap between quantum continuous measurements and full counting statistics, GT Landi, MJ Kewming, MT Mitchison, PP Potts, PRX Quantum 5, 020201
Furthermore understanding of the role of quantum measurement in many-body quantum systems and FTs was explored in collaboration with a PhD student, yielding a general description of these processes. While Feedback control was not investigated, the primary objectives of extending FTs to stochastic measurements was achieved and is now under review at Physical Review E. The arXiv preprint of the manuscript can be found freely at
M2. Quantum stochastic thermodynamics in the mesoscopic-leads formulation, LP. Bettmann, MJ. Kewming, GT. Landi, J. Goold, MT. Mitchison arXiv:2404.06426
1.2.2 Work Package 2
In WP2, the researcher developed several testable protocols, alongside his collaborators, and a PhD student. These protocols included a novel Kinetic Uncertainty relation that set the thermodynamic limits of precision in a quantum clock, which was subsequently tested experimentally and published:
M3. Effect of Measurement Backaction on Quantum Clock Precision Studied with a Superconducting Circuit, X He, P Pakkiam, AA Gangat, MJ Kewming, GJ Milburn, A Fedorov, Physical Review Applied 20 (3), 034038
Furthermore, a proposal to test the thermodynamic uncertainty relations (TUR) was also investigated under a continuous measurement protocol using quantum point contacts, the proposal of which was published in:
M4. Thermodynamics of a continuously monitored double-quantum-dot heat engine in the repeated interactions framework, LP Bettmann, MJ Kewming, J Goold, Physical Review E 107 (4), 044102
The experimental feasibility of this protocol are now being investigated by our collaborators in the Ares group at Oxford University. A secondment was planned to facilitate this development, but was reduced to a shorter group visit in lieu of dissemination plans at conferences.
An additional theoretical investigation into fluctuation theorems and Landauer’s erasure from quantum trajectories is also under review in the manuscript M2 further signifying the success of WP2.
1.2.3 Work Package 3
In WP3, the researcher collaborated closely with the experimental team led by Prof. Arkady Fedorov at the University of Queensland. They implemented the testable protocol developed by the researcher, focusing on the Kinetic Uncertainty relation that establishes the thermodynamic limits of precision in a quantum clock. This protocol was successfully tested experimentally and subsequently published in M3. While feedback control was not incorporated into this study, there is now an experiment currently being implemented in the same group focused on studying the TUR under feedback control which was devised by the researcher and the group of Prof. Fedorov.
A tangential experiment, as devised by the researcher in collaboration with the host, and the Prof. Ferdinand Schmidt-Kaler’s group at the University of Mainz focused on the relationship between quantum correlations and work extraction is currently under review at Physical Review Letters. This research further enhanced the hosts and researchers networks with experimental teams, in accordance with the objectives of WP3. The arXiv preprint can be found freely at:
M5. Demonstration of energy extraction gain from non-classical correlations, A. Stahl, MJ. Kewming, J. Goold, J. Hilder, UG.Poschinger F Schmidt-Kaler, arXiv:2404.14838
These two manuscripts mark successful competition of WP3, as well as going beyond the scope of the projects as both experimental collaborations were successfully completed during the duration of the Fellowship.
