Spontaneous Unitarity Violation and Quantum State Reduction

Abstract

One of the central foundational problems in quantum mechanics is the inability of Schr\"odinger's unitary time evolution to describe measurement of a quantum state. Recent developments in models of spontaneous unitarity violation (SUV) propose that quantum state reduction can emerge as a thermodynamic phenomenon, offering a natural resolution to the measurement problem. This paper investigates the philosophical implications of SUV in relation to the nature of probabilities in quantum mechanics and statistical mechanics. It provides an alternate interpretation of probabilities in quantum mechanics that aligns with (and improves upon) the arguments of the propensity interpretation of probabilities.