Constructing qubits in physical systems

2001/01/18 by Lorenza Viola, Emanuel Knill, Raymond Laflamme · 2 citations
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph

paper · pdf · doi:10.1088/0305-4470/34/35/331

16 pages, no figures; IoP LaTeX2e style. Submitted to J. Phys. A: Math. Gen

arxiv created 2001/01/18 · openalex publication_date 2001/08/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30

Abstract

The notion of a qubit is ubiquitous in quantum information processing. In spite of the simple abstract definition of qubits as two-state quantum systems, identifying qubits in physical systems is often unexpectedly difficult. There is an astonishing variety of ways in which qubits can emerge from devices. What essential features are required for an implementation to properly instantiate a qubit? We give three typical examples and propose an operational characterization of qubits based on quantum observables and subsystems.

Citations

• Noncommuting Mixed States Cannot Be Broadcast
• Quantum computation using decoherence-free states of the physical operator algebra
• Quantum theory, the Church–Turing principle and the universal quantum computer
• The Physical Implementation of Quantum Computation
• Quantum Theory: Concepts and Methods

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