Reducing the overhead for quantum computation when noise is biased

TL;DR

This paper presents a fault-tolerant quantum computation scheme optimized for biased noise, reducing overhead by using Clifford gates and specialized magic state distillation, especially effective when Z errors dominate.

Contribution

The authors introduce a novel fault-tolerance scheme leveraging noise bias, with a magic state preparation gadget and concatenation techniques that outperform standard methods under high bias conditions.

Findings

Lower overhead for noise bias > 10

Effective magic state distillation at physical level

Outperforms standard constructions in relevant noise regimes

Abstract

We analyse a model for fault-tolerant quantum computation with low overhead suitable for situations where the noise is biased. The basis for this scheme is a gadget for the fault-tolerant preparation of magic states that enable universal fault-tolerant quantum computation using only Clifford gates that preserve the noise bias. We analyse the distillation of $|T\rangle$-type magic states using this gadget at the physical level, followed by concatenation with the 15-qubit quantum Reed-Muller code, and comparing our results with standard constructions. In the regime where the noise bias (rate of Pauli $Z$ errors relative to other single-qubit errors) is greater than a factor of 10, our scheme has lower overhead across a broad range of relevant noise rates.