On fault tolerant single-shot logical state preparation and robust long-range entanglement

Fuente: arXiv
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Main Authors: Bergamaschi, Thiago, Liu, Yunchao
Format: Preprint
Published: 2024
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author Bergamaschi, Thiago
Liu, Yunchao
author_facet Bergamaschi, Thiago
Liu, Yunchao
contents Preparing encoded logical states is the first step in a fault-tolerant quantum computation. Standard approaches based on concatenation or repeated measurement incur a significant time overhead. The Raussendorf-Bravyi-Harrington cluster state offers an alternative: a single-shot preparation of encoded states of the surface code, by means of a constant depth quantum circuit, followed by a single round of measurement and classical feedforward. In this work we generalize this approach and prove that single-shot logical state preparation can be achieved for arbitrary quantum LDPC codes. Our proof relies on a minimum-weight decoder and is based on a generalization of Gottesman's clustering-of-errors argument. As an application, we also prove single-shot preparation of the encoded GHZ state in arbitrary quantum LDPC codes. This shows that adaptive noisy constant depth quantum circuits are capable of generating generic robust long-range entanglement.
format Preprint
id arxiv_https___arxiv_org_abs_2411_04405
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On fault tolerant single-shot logical state preparation and robust long-range entanglement
Bergamaschi, Thiago
Liu, Yunchao
Quantum Physics
Strongly Correlated Electrons
Preparing encoded logical states is the first step in a fault-tolerant quantum computation. Standard approaches based on concatenation or repeated measurement incur a significant time overhead. The Raussendorf-Bravyi-Harrington cluster state offers an alternative: a single-shot preparation of encoded states of the surface code, by means of a constant depth quantum circuit, followed by a single round of measurement and classical feedforward. In this work we generalize this approach and prove that single-shot logical state preparation can be achieved for arbitrary quantum LDPC codes. Our proof relies on a minimum-weight decoder and is based on a generalization of Gottesman's clustering-of-errors argument. As an application, we also prove single-shot preparation of the encoded GHZ state in arbitrary quantum LDPC codes. This shows that adaptive noisy constant depth quantum circuits are capable of generating generic robust long-range entanglement.
title On fault tolerant single-shot logical state preparation and robust long-range entanglement
topic Quantum Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2411.04405