Research papers

Quantum mechanics describes a wave that spreads and interferes; a detector records a particle at one place and time. Anchored Causality Theory (ACT) takes both seriously: the electron is a stable wave-mode structure of one composite field, its modes interfering like a sound wave’s harmonics, never a particle on a path. A detector’s bath of photons and atoms keeps a record that tells the alternatives apart, say the two lobes of a wave behind two slits. The record is released when no later interaction the system will actually undergo can restore interference between them. One alternative becomes an event: a mark in the one actual history. No observer is needed; Schrödinger evolution is never modified. The wave is what exists; the particle is what happens.

Four experiments carry the argument. An unread lossy slab removes the fringes; a tunable coupling sets their fading rate; a filter selects components of one field, with no event before release; and single marks build fringes when no path is recorded, a particle pattern when one is. With the quantum erasers, they exclude each earlier placement tested for an event of ACT’s kind; release is the earliest they allow.

ACT changes no quantum prediction; it claims that one history of released records is actual. One mark per event is proved where records never return, assumed beyond. Given refinable records, two requirements force the Born weights: a record’s chance here is unchanged by records elsewhere and continuous in the wave. A covariant release criterion is open.

Anchored Causality Theory (ACT) holds that a quantum system is never a particle: it is one wave, a quantum field with internal structure, from start to finish, and the particle is what happens, the mark a detector makes. The main accounts of quantum mechanics keep a particle somewhere, at the detector or on a hidden path, or they keep every outcome, each in a world of its own; ACT does neither. A bath, not an observer, makes the mark: the detector’s surroundings keep a record, and when the record has passed beyond recovery one event occurs, with the Schrödinger equation unchanged. This paper works out the bath’s part for matter waves. Wave mechanics began as a realist attempt to understand the wave character of matter, but neither de Broglie’s nor Schrödinger’s program produced a mechanism by which an extended wave yields one localized event. Born’s rule removed that question from dynamics, and decoherence explains the suppression of interference without supplying the occurrence of an outcome. Objective-collapse models restored that demand, at the cost of autonomous stochastic localization dynamics. ACT is an alternative in which the event-rate structure is inherited from a physical quantum Brownian motion bath rather than postulated, while the actuality of one resulting history is postulated explicitly. Global dynamics are unmodified; the environment’s record structure supplies the event hazard and constrains the realized instrument class. We give a two-condition event law: an admissible fragment-readable record architecture makes an event eligible, while accessible irreversible phase loss fixes the hazard $h(t)=\dot\Phi_{\rm irr}(t)$, with no new constant and no adjustable threshold, within a stated regime boundary: the event rate is read off the same coupling that draws the decoherence curve, and in the nondemolition case the two curves are one. Irreversibility is defined through recoverable phase distinguishability, and scoped to CP-divisible dynamics. Two models are worked through: an exactly solvable pure-dephasing model in which the Born weights are forced by ensemble consistency and an explicit outcome-neutrality hypothesis, which checks in the model the general result of the companion paper, where six stated premises on the law of chance force them for every released record; and a Caldeira–Leggett Brownian-particle model exhibiting the noise–dissipation pairing. A selection theorem shows that fragment-accessible records support only classical post-processings of the localization instrument; its role is ontological rather than empirical. A detector is any body that keeps an irreversible record of the mode it couples to; no observer enters. The framework posits an exclusive outcome register and the actuality of one record history, and adds one event-law identification; in the record-algebra class of the companion paper the first is a theorem and the identification is the nondemolition case of a general law, so that one primitive commitment remains.

Anchored Causality Theory holds that a quantum system is never a particle: it is one wave, a quantum field with internal structure, from start to finish, and the particle is what happens, the mark a detector makes when the bath around it carries a record beyond recovery. The main accounts of quantum mechanics keep a particle somewhere, at the detector or on a hidden path, or they keep every outcome, each in a world of its own; ACT does neither. This paper says when a record has passed beyond recovery — when it is released — and what law the marks then follow. A continuously monitored quantum system emits an output whose observables commute with one another and with every later system observable; Belavkin’s nondemolition principle identifies these output observables as a classical past. We take that structure as the carrier of actuality and ask what more is needed for a single, exclusive, causally ordered history of events. Three results follow. First, exclusivity of outcomes is a theorem: the record algebra is commutative for arbitrary system Hamiltonian and coupling, its spectrum is the set of histories, and the joint spectral projectors are orthogonal with Born probabilities equal to the instrument path measure. Second, we define release of a record as commutation with the system’s physically accessible future — later system observables and fresh records, through every return path the interaction network provides — and prove a bound tying this algebraic condition to the recoverable-phase functional of the companion paper: for a binary record with gap $\Delta$, the phase distinguishability accessible through any observable $A$ is at most $\lVert\omega_{\rm off}\rVert_1\,\lVert[R,A]\rVert/\Delta$. Release is exactly the condition under which attaching actuality to a record alters no accessible prediction for any state. Attached earlier, by a rule of the kind treated here — the actual history proceeds from the record, the unselected alternatives no longer enter that history, and the global wave is untouched — actuality changes what the actual history predicts, and the recoherence experiments exclude each such earlier placement that has been tested. The weights are not imported: an appendix shows that six stated premises — one wave with one covariant law of chance, one actual history, no record where the wave has no component, no signalling for every division of the network, physically realisable refinement of records, and continuity — force the chance of a released record to be its squared amplitude, by Zurek’s argument in Barnum’s no-signalling form. Third, outside the free-output setting the criterion does work that nondemolition alone does not: under time-delayed return the in-flight record is nondemolition but not released, and anchoring is deferred to the exit record; under intra-environment scrambling a record leaves the absolute centre of the future algebra while remaining central relative to the system. The event law is the instrument path measure, with the companion paper’s hazard $h=\dot\Phi_{\rm irr}$ as its nondemolition corollary and the diffusive stochastic master equation as the large-local-oscillator limit of a counting history; its records carry no particle labels, so it treats identical particles with nothing added. The framework adds one primitive commitment — one point of the released-record spectrum is actual — and no new field, constant, threshold or noise. Every numerical statement is verified by a deposited script; the results on records and release are exact in a finite collision model.

Sonderegger, K. (2026). Anchored Causality Theory: A Record-History Ontology for Open Quantum Systems. Preprint, version 3.3, October 2026. https://anchoredcausality.org/papers/ACT_Flagship_A_Record_History_Ontology_2026-10.pdf

Sonderegger, K. (2026). From Matter Waves to Anchored Events: Anchored Causality Theory and Quantum Brownian Measurement. Preprint, version 2.5, October 2026. https://anchoredcausality.org/papers/ACT_Paper_I_From_Matter_Waves_to_Anchored_Events_2026-10.pdf

Sonderegger, K. (2026). Released Records: Nondemolition Relative to the Accessible Future as a Criterion for Quantum Events. Preprint, version 1.8, October 2026. https://anchoredcausality.org/papers/ACT_Paper_II_Released_Records_2026-10.pdf

Sonderegger, K. (2026). Anchored Causality Theory (website), v5.40. https://anchoredcausality.org. ORCID 0009-0005-9539-3584.