Quantum Switch as a Minimal P Tact (П-такт) Cycle

The Everett interpretation of quantum mechanics establishes a radical but internally consistent premise: the universal wave function evolves unitarily and deterministically at all times, without collapse and without any privileged notion of measurement. While this framework has been extensively discussed at the conceptual level, many of its structural implications—particularly concerning causality, temporal order, and process composition—have remained only implicitly formulated. In this work, we present a systematic formalization of Everett’s process logic using discrete process units (P-Tacts) and show that the quantum switch naturally emerges as a minimal closed P-Tact cycle. Within this framework, indefinite causal order is not introduced as an additional postulate or informational resource, but arises as a direct consequence of cyclic unitary process composition, fully consistent with universal quantum evolution. We begin by revisiting Everett’s relative-state formulation from a process-theoretic perspective. Everett’s insistence on the universality of unitary dynamics already removes any fundamental distinction between “before” and “after” at the level of the global wave function. However, without an explicit discrete process structure, the emergence of causal relations and effective temporal ordering remains conceptually underdetermined. The P-Tact framework addresses this gap by identifying the primitive unit of quantum dynamics as a discrete, operationally realizable unitary process step, rather than a continuous time parameter. By constructing closed cycles of P-Tacts, we demonstrate that causal relations become relational properties of process graphs rather than reflections of an underlying time axis. The minimal non-trivial realization of such a cycle corresponds precisely to the operational structure of the quantum switch. In this setting, the control system does not select between alternative temporal orders; instead, it coherently selects between alternative process paths within a closed P-Tact cycle. Indefinite causal order thus appears as an intrinsic structural feature of the process graph, not as a violation or suspension of causality. This interpretation places the quantum switch firmly within the Everettian framework. Rather than extending or modifying Everett’s interpretation, the quantum switch operationally realizes one of its latent consequences: the coexistence and coherent superposition of multiple process orderings within a single universal wave function. The absence of a fundamental time parameter in Everett’s theory finds a concrete expression here, where effective temporal order emerges only upon projection of the underlying cyclic process structure onto an acyclic subgraph. Furthermore, the P-Tact cycle formalism provides a unifying language connecting several previously distinct domains: quantum control of causal order, quantum teleportation, entanglement-mediated process composition, and the emergence of time and causality from unitary dynamics. From this perspective, the quantum switch represents not an isolated protocol, but the simplest experimentally accessible manifestation of a general class of Everettian process cycles. In conclusion, this work advances Everett’s original program by making explicit the process-level structures implicit in his formulation. The quantum switch, understood as a minimal P-Tact cycle, serves as a concrete bridge between foundational quantum theory and modern experiments on indefinite causal order. In doing so, it demonstrates that recent developments in quantum information theory do not depart from Everett’s vision, but instead bring it to a new level of formal and operational clarity. Bibliography Pavlov, M. (2026). Quantum Switch as an Emergent Process Structure from Discrete Process Tacts (П-такт).Zenodo. https://doi.org/10.5281/zenodo.18498181 Quantum Switch and Teleportation.Zenodo. https://doi.org/10.5281/zenodo.18509173 Emergence of Causality, Gravity, Time, and Three-Dimensional Space from Discrete P-Tact (П-такт) Dynamics.Zenodo. https://doi.org/10.5281/zenodo.18504244 P-Tact (П-такт) as the Primitive Unit of Quantum Theory.Zenodo. https://doi.org/10.5281/zenodo.18516711 Indefinite Causal Order as Superposition of Process Graphs.Zenodo. https://doi.org/10.5281/zenodo.18519010 Everett Interpretation Formalized via P-Tact (П-такт) Path Graphs.Zenodo. https://doi.org/10.5281/zenodo.18524745 Emergence of Time from P-Tact Entanglement (Происхождение времени).Zenodo. https://doi.org/10.5281/zenodo.18526015 From Indefinite Causal Order to Definite Process Order:A Topological Reconstruction of the Quantum Switch via Discrete P-Tacts (П-такт).Zenodo. https://doi.org/10.5281/zenodo.18526959 Causality and Arrow of Time.Zenodo. https://doi.org/10.5281/zenodo.18549931