Irreversibility, coherence and quantum fluctuation theorems
File(s)
Author(s)
Hinds Mingo, Erick Benjamin
Type
Thesis
Abstract
Irreversible processes have long been the focus of much attention in physics, forming cornerstones of thermodynamics and the foundations of quantum mechanics (principally the measurement problem). Recent interest in the marriage of these two fields has laid bare the partial inadequacy of definitions of thermodynamic work in a quantum context. Its problems are fundamental to quantum mechanics, in that projective measurements irreversibly destroy coherence in a state. To attempt to resolve this incompatibility, we begin with a deterministic quantum work process that adequately generalises the Newtonian framework for deterministic work processes. In doing so, we uncover a structure that has strong links to an old problem in probability theory on the decomposability of random variables. Crucially, we define coherent work as a state and Hamiltonian pair, sidestepping the measurement problem. We then look to fluctuation theorems which detail the thermodynamic irreversibility, and further develop a recent framework to show how our coherent work state appears just as Newtonian work appears in Crooks’ fluctuation theorem – providing an infinite hierarchy of correction terms. To round this off, we discuss the implications of incorporating additional observables, both commuting and complementary, on work processes and thermodynamics.
Version
Open Access
Date Issued
2020-04
Date Awarded
2020-10
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Jennings, David
Mintert, Florian
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)