The Sound of Decoherence

Abstract: We explore an unconventional bridge between quantum mechanical density matrices and sound by mapping elements of the density matrix and their phases to auditory signals, thus introducing a framework for Open Quantum Sonification. Employing the eigenstates of the Hamiltonian operator as a basis, each quantum state contributes a frequency proportional to its energy level. The off-diagonal terms, which encode coherence and phase relationships between energy levels, are rendered as binaural signals presented separately to the left and right ears. We illustrate this method within the context of open quantum system dynamics governed by Lindblad equations, presenting first an example of quantum Brownian motion of a particle in a thermal bath, and second, a recoherence process induced by boundary driving that results in spin-helix states. This document serves as a companion to the corresponding audio visual simulations of these models available on the YouTube channel Open Quantum Sonification with the Python Codes on GitHub. The auditory analogy presented here provides an intuitive and experiential means of describing quantum phenomena such as tunnelling, thermalisation, decoherence, and recoherence.