Composite anyon coding and the initialization of a topological quantum computer

TL;DR

This paper demonstrates that in topological quantum computation, initial state preparation can be simplified by using composite anyons and braiding, reducing reliance on challenging non-topological operations.

Contribution

It introduces a method to initialize topological quantum computers using composite anyons, enabling state distillation solely through braiding operations.

Findings

Initial state preparation can be achieved via braiding of composite anyons.

Logical information is encoded in a subsystem code with gauge degrees of freedom.

The approach relaxes the need for non-topological state preparation procedures.

Abstract

Schemes for topological quantum computation are usually based on the assumption that the system is initially prepared in a specific state. In practice, this state preparation is expected to be challenging as it involves non-topological operations which heavily depend on the experimental realization and are not naturally robust against noise. Here we show that this assumption can be relaxed by using composite anyons: starting from an unknown state with reasonable physical properties, it is possible to efficiently distill suitable initial states for computation purely by braiding. This is achieved by encoding logical information in a subsystem code with gauge system corresponding to the internal degrees of freedom of composite objects.