Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Physics and Astronomy

Committee Member

Murray Daw, Committee Chair

Committee Member

Dieter Hartmann

Committee Member

Mark Leising

Committee Member

Sumanta Tewari

Committee Member

Antony Valentini


This thesis explores the possibility that quantum probabilities arose thermodynamically. It considers both what is required of a quantum theory for this to happen, and empirical consequences if it is the case. A chief concern is the detection of primordial 'quantum nonequilibrium', since this is by definition observably distinct from textbook quantum physics. The mode of operation is almost exclusively quantum field theoretic, due to the nature of quantum nonequilibrium. Chapters 2, 3, 4, and 5, are adaptations of references [1,2,3], and [4], respectively.

Chapter 2 proposes (information) entropy conservation as a minimal requirement for a theory to feature classical-style thermodynamic relaxation. The resulting structure is dubbed 'the iRelax framework'. This ensures that theories retain the time-reversibility of classical mechanics, while also enabling relaxation and entropy rise on a de facto basis. Both classical mechanics and de Broglie-Bohm quantum theory are shown to be special cases. Indications for a possible extension or unification of de Broglie-Bohm theory are briefly highlighted.

Chapter 3 discusses 'quantum relaxation' to 'quantum equilibrium' in de Broglie-Bohm theory and considers means by which quantum nonequilibrium may be prevented from relaxing fully. The method of the drift-field is introduced. A systematic treatment of nodes is given, including some new results. Quantum states are categorized cleanly according to global properties of the drift-field, and a link is made between these and quantum state parameters. A category of quantum states is found for which relaxation is significantly impeded, and may not complete at all.

Chapter 4 considers the possibility that primordial quantum nonequilibrium may be conserved in the statistics of a species of relic cosmological particle. It discusses necessary factors for this to happen in a background inflationary cosmology. Illustrative scenarios are given both in terms of nonequilibrium particles created by inflaton decay, as well as relic vacuum modes for species that decoupled close to the Planck temperature. Arguments are supported by numerical calculations showing both perturbative couplings transferring nonequilibrium between fields, and also nonequilibrium causing standard quantum measurements to yield anomalous results.