2004/08/23 by Robin Blume-Kohout, Wojciech H. Zurek · 3 citations
Computer Science · Physics and Astronomy · #Computer science #Decoherence-free subspaces #Observable #Open quantum system #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum decoherence #Quantum entanglement #Quantum error correction #Quantum information #Quantum information science #Quantum mechanics #Qubit #Theoretical computer science #Theoretical physics #quant-ph
paper · pdf · doi:10.1007/s10701-005-7352-5
published as Foundations of Physics 35, 1857 (2005) · 21 pages, 6 figures, RevTex 4. Submitted to Foundations of Physics (Asher Peres Festschrift)
arxiv created 2004/08/23 · openalex publication_date 2005/11/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
As quantum information science approaches the goal of constructing quantum computers, understanding loss of information through decoherence becomes increasingly important. The information about a system that can be obtained from its environment can facilitate quantum control and error correction. Moreover, observers gain most of their information indirectly, by monitoring (primarily photon) environments of the "objects of interest." Exactly how this information is inscribed in the environment is essential for the emergence of "the classical" from the quantum substrate. In this paper, we examine how many-qubit (or many-spin) environments can store information about a single system. The information lost to the environment can be stored redundantly, or it can be encoded in entangled modes of the environment. We go on to show that randomly chosen states of the environment almost always encode the information so that an observer must capture a majority of the environment to deduce the system's state. Conversely, in the states produced by a typical decoherence process, information about a particular observable of the system is stored redundantly. This selective proliferation of "the fittest information" (known as Quantum Darwinism) plays a key role in choosing the preferred, effectively classical observables of macroscopic systems. The developing appreciation that the environment functions not just as a garbage dump, but as a communication channel, is extending our understanding of the environment's role in the quantum-classical transition beyond the traditional paradigm of decoherence.