Quantum Information is Physical

TL;DR

This paper explores the fundamental principles of quantum information, emphasizing quantum error correction, entanglement for decoherence protection, and practical criteria for building quantum computers, illustrated by quantum dot spin states.

Contribution

It provides a comprehensive overview of quantum error correction, entanglement's role in protecting quantum information, and practical implementation criteria, including a specific proposal using quantum dots.

Findings

Quantum entanglement effectively protects quantum states from decoherence.

Five criteria are essential for realizing a quantum computer in the lab.

A proposal for a quantum computer using coupled quantum dot spin states.

Abstract

We discuss a few current developments in the use of quantum mechanically coherent systems for information processing. In each of these developments, Rolf Landauer has played a crucial role in nudging us and other workers in the field into asking the right questions, some of which we have been lucky enough to answer. A general overview of the key ideas of quantum error correction is given. We discuss how quantum entanglement is the key to protecting quantum states from decoherence in a manner which, in a theoretical sense, is as effective as the protection of digital data from bit noise. We also discuss five general criteria which must be satisfied to implement a quantum computer in the laboratory, and we illustrate the application of these criteria by discussing our ideas for creating a quantum computer out of the spin states of coupled quantum dots.