Equivalence of dynamics of disordered quantum ensembles and semi-infinite lattices

TL;DR

This paper introduces a formalism that maps the dynamics of disordered quantum ensembles onto semi-infinite lattice models, enabling efficient computation and geometric interpretation of coherence loss.

Contribution

It presents a novel mapping formalism that connects disordered quantum dynamics with lattice models, facilitating analysis and simulation of complex quantum systems.

Findings

Exact dynamics of disordered ensembles can be computed via lattice models.

The formalism provides a geometric interpretation of coherence loss.

The approach enables bidirectional mapping between quantum ensembles and lattice dynamics.

Abstract

We develop a formalism for mapping the exact dynamics of an ensemble of disordered quantum systems onto the dynamics of a single particle propagating along a semi-infinite lattice, with parameters determined by the probability distribution of disorder realizations of the original heterogeneous quantum ensemble. This mapping provides a geometric interpretation on the loss of coherence when averaging over the ensemble and allows computation of the exact dynamics of the entire disordered ensemble in a single simulation. Alternatively, by exploiting the reverse map, one can obtain lattice dynamics by averaging over realisations of disorder. The potential of this equivalence is showcased with examples of the map in both directions: obtaining dephasing of a qubit via mapping to a lattice model, and solving a simple lattice model via taking an average over realizations of disorder of a unit cell.