Random Unitary Models and their Localization Properties

TL;DR

This paper explores models of quantum dynamics using random unitary matrices, demonstrating localization properties relevant to condensed matter physics and abstract quantum systems.

Contribution

It introduces and analyzes new random unitary models with band structure, proving dynamical localization in these systems.

Findings

Proven localization in models derived from physical approximations.

Identification of key features leading to localization.

Analysis of abstract models with similar properties.

Abstract

This paper aims at presenting a few models of quantum dynamics whose description involves the analysis of random unitary matrices for which dynamical localization has been proven to hold. Some models come from physical approximations leading to effective descriptions of the dynamics of certain random systems that are popular in condensed matter theoretical physics, whereas others find their roots in more abstract considerations and generalizations. Although they may differ in details, the operators describing the models all have in common the following key features on which their analysis relies heavily: their dynamics is generated by unitary operators on an infinite dimensional underlying Hilbert space which have a band structure when expressed as matrices in a certain basis and the randomness of the models lies in phases of the matrix elements.