decoherence
Compiled with AI assistance and selectively reviewed. Please consult the cited passages; the books remain the authoritative source. About this companion
Editorial synthesis · provisional
Definition
Decoherence concerns the loss of accessible quantum interference through specified interactions with surroundings, making alternatives appear classically distinct without by itself selecting one actual outcome. RB1 also discusses decoherence as a consistency condition on histories, and attributes a stronger transaction-induced account to RTI. PB stresses the limits of categorical representation; RB3 emphasizes the material cost of protecting fragile quantum possibilities.
Explanation
AB explains apparent everyday definiteness through environmental records that suppress interference, then explicitly separates the further resolution of a single outcome. Its narrative note repeats that distinction. PB similarly requires specified interactions and a reduced description: merely moving to a category of completely positive maps does not yield decoherence, no-signaling or unique outcome selection.
RB1 preserves several interpretive settings. In its RTI exposition, actualized transactions are said to induce decoherence; in its account of Kastner's criticism of Many-Worlds, environmental decoherence gives only approximate non-interfering branches. Quantum Darwinism supplies robust pointer states and an analogy of environmental selection. The consistent-histories passage restricts probability assignments to suitable coarse-grained histories and expressly denies that consistency alone selects a unique global history or explains classicality. Its further fitness language remains analogical.
RB3 treats decoherence as a cost of openness in quantum computing: fragile possibilities require protective material organization amid disturbance and unwanted coupling. This philosophical application does not convert every listed engineering error into a definition of decoherence, nor does it supply a new rule selecting actual outcomes.
Scope and attribution
AB, PB, RB1 and RB3 own direct treatments; no direct RB2 treatment was found. Environmental decoherence, the histories condition, RTI's actualization claim and RB3's philosophical application are distinguished rather than flattened into one causal account.
AB — The Actual Book
Environmental records render interference practically invisible. Which outcome becomes actual remains a further relational resolution, a distinction reiterated by the narrative note.
Occurrence locators: 26, 27; Notes: 236, 237.
PB — The Possible Book
Decoherence requires specified interactions and reduction of description, not merely the CPM construction. Neither that construction nor the pure-state formalism singles out an actual outcome.
Occurrence locators: 174.
RB1 — The Real Book, Volume I: The Possible Is Real
RB1 juxtaposes RTI's transaction-induced decoherence, Kastner's criticism of approximate branch separation, pointer-state robustness and a consistent-histories condition. Its explicit qualifications prevent environmental selection and analogical fitness from becoming a unique-outcome solution.
Occurrence locators: 64, 69, 77, 254, 255.
RB3 — The Real Book, Volume III: Murmurations
The cost-of-openness discussion stresses the protection and material organization needed to sustain fragile quantum possibilities. Environmental coupling and practical disturbances qualify any celebration of unconstrained openness.
Occurrence locators: 58.
Background used in the editorial explanation
Domain-specific mechanisms and wider analogies remain distinguished. Original definitions retain their scope; local cross-references do not rewrite them. Named theories and mechanisms are distinguished from neighboring background, homonyms and the author’s own synthesis. Reproduced AI passages retain their separate voice.