Wider Research Context: There has recently been a renaissance in quantum thermodynamics, with many new theoretical and experimental insights into foundational and applicable uses of thermodynamic and statistical mechanical ideas in quantum theory. In this context, some recent work has explored the thermodynamics of quantum measurements, even up to thermodynamic considerations of conceptual issues such as the infamous ‘measurement problem’.

Research Questions: In this project, both the thermodynamic nature of quantum processes, and the quantum nature of thermodynamic processes will be studied. A statistical mechanical model of quantum measurements will be explored to answer the questions:

-         What can be learned about the properties of closed-system equilibration from simulations of the unitary dynamics of isolated fermionic systems?   

-         What do the dynamics of different quantum entropies look like in the closed-system context?

-         How can the statistical measurement model be reconciled with the standard model of quantum measurements?

-         Can this model be used to answer conceptual questions concerning the emergence of classicality and the nature of measurement in quantum theory, for instance by providing insight into the ‘Wigner's Friend’ paradox?

Methods: Both theoretical and computational methods will be used to address these questions. Fortran simulations of Fermi-Hubbard site dynamics will be used to study the spontaneous emergence of ‘objectivity’ in a simple measurement model based on Quantum Darwinism and closed-system equilibration, with possible links to future experiments. This will also be used to theoretically explore the connection between the thermodynamic measurement model and the conventional von Neumann ‘standard model of measurement’, with the goal of connecting the model to weak measurement theory. Python simulations of isolated Ising spin chain dynamics will be produced to study entropy and equilibration in isolated quantum systems, and entropy will be further studied theoretically in the context of quasiprobability distributions. Finally, theoretical and numerical models will be made of Wigner's Friend and ‘Interaction-Free Measurement’ scenarios in the presence of environments.