Decoherence and memory: SMM/DTT and objective collapse models

01The question behind this comparison

Decoherence occurs when a system becomes correlated with degrees of freedom that are not controlled in a later experiment. Relative phases can remain present in the total state while disappearing from the reduced statistics available locally. A memory is a physical correlation that persists and can influence a later operation. These concepts overlap, but neither implies the other: an environment can decohere a system while retaining information that later returns to it.

SMM/DTT’s source memory gives this distinction a natural role. Inner work may store relations absent from the completed record, and later completion can reveal some of them. The relevant question is whether the discarded variables are merely bookkeeping or have operational consequences. A theory of retained records therefore benefits from multi-time interventions that distinguish irreversible loss, temporary inaccessibility and deliberately protected phase memory. ^{[3] [4]}

02The SMM/DTT starting point

The Single Monad Model begins with one nonspatial generative source. The Duality of Time Theory distinguishes the source’s inner production from the outer order in which completed records become accessible. Its six inner levels are nested functional roles of one process: a higher role organizes lower-level work. The seventh is the completion or observation interface. They are neither six independent clocks nor six additional time coordinates.

This distinction supplies a useful research question: which features of an observed world can follow from the way a source produces, retains and releases information? A concrete answer needs a state space, an autonomous update, retained memory and a rule connecting completion to an accessible measurement. In the constructions discussed here, those mathematical ingredients are stated explicitly. A successful finite example establishes what its specified mechanism can do; further arguments connect it to physical particles, spacetime or universal laws. ^[1]

03How the comparator works

Objective collapse theories modify quantum dynamics so that sufficiently macroscopic alternatives are suppressed by a physical stochastic process. In GRW-type and continuous-spontaneous-localization families, the modification contains a rate and a spatial or mass-related structure. Amplification makes microscopic coherence relatively persistent while reducing macroscopic superpositions. These are dynamical proposals with measurable consequences, rather than interpretations that necessarily preserve every prediction of ordinary unitary quantum theory.

Outer completion in DTT is not automatically an objective collapse. A completion channel may simply expose a decohered record or condition on an ordinary outcome. It becomes a collapse proposal only when the state evolution changes in a specified way, with a probability law, energy accounting and a physical scale. Collapse models consequently provide a demanding comparison: they illustrate how an account of definite records can take quantitative risks. No bound on their parameters directly bounds an unspecified generative process; the two mechanisms must first be translated into comparable observable dynamics. ^[2]

04The decisive comparison

Collapse dynamics and environmental decoherence can both reduce the off-diagonal elements of a density operator. Their physical interpretation differs when the environment is controllable: ordinary unitary decoherence may be reversed, whereas a fundamental collapse law adds an irreducible loss channel of the specified strength. DTT has to decide which kind of completion it proposes before these comparisons can produce a prediction.

A source that retains hidden coherent information resembles an environment or enlarged unitary system. A source that deletes alternatives according to an objective stochastic rule resembles a collapse mechanism. The same observed purity at one time cannot distinguish them. Multi-time recovery protocols, together with heating and noise measurements appropriate to the proposed law, can constrain a particular model. The six nested roles do not alone set that law’s rate, dimensional scale or energy balance. The positive opportunity for DTT is to connect irreversible record retention to a source resource constraint, making a quantitative relation that conventional environmental models or phenomenological collapse parameters do not impose. That would move the proposal from an interpretation of lost coherence to a constrained mechanism. ^{[2] [3] [4]}

05Worked benchmark

Start with (|0⟩+|1⟩)|e⟩/√2 and let an interaction correlate the alternatives with normalized environment states |e₀⟩ and |e₁⟩. The reduced system state has diagonal entries 1/2 and off-diagonal entries γ/2, where γ=⟨e₁|e₀⟩. Its eigenvalues are (1±|γ|)/2 and its purity is [1+|γ|²]/2.

If |γ|=0.6, the purity is 0.68. If the environmental alternatives become orthogonal, purity falls to 1/2 and the system looks maximally mixed. A controlled reversal of the joint interaction can nevertheless restore the original pure state when all relevant degrees of freedom remain coherent. This is why a completed local archive cannot be identified with the full microscopic state. The entropy of its reduced description measures inaccessible correlations under a chosen partition; it is not, by itself, evidence that information has been fundamentally destroyed. ^{[3] [4]}

06What follows for the source programme

The practical value of a source-memory model is that it can predict when a simple one-time description fails. If every future intervention depends only on the retained density operator, an ordinary channel is enough. If different preparation histories with that same operator produce different responses, a larger memory or process tensor is required. The additional structure becomes explanatory when its organization constrains those responses, instead of merely storing a complete list of previously observed outcomes. ^{[3] [4]}

THE SAME QUESTION, DIFFERENT STARTING POINTS

The comparison at a glance

Continue on SMONAD

• Retained observations versus predictive states →

  Connects this comparison with the author’s underlying construction.

• Eliminating hidden variables creates memory →

  Connects this comparison with the author’s underlying construction.

• Toy models of projection-induced irreversibility →

  Connects this comparison with the author’s underlying construction.

• When memory can be represented by one time →

  Connects this comparison with the author’s underlying construction.

• SMM/DTT research claim map: results, assumptions and open targets →

  Places the comparison alongside the programme’s published results, assumptions and open targets.