Ultimate goal of the work described in this paper has been the construction of a local causal model of quantum theory including quantum field theory.The original model has been refined in a number of refinement steps.As the so far latest refinement step, quantum loops are identified as the elementary processes of spacetime dynamics and quantum field dynamics.Quantum loops are processes that constitute quantum objects.In the causal model of quantum loops and quantum objects presented here, the collective behavioral processes involve the elementary units of spacetime and the associated elementary units of quantum of fields.As such, quantum loop processes are the sources of gravitational fields (i.e., spacetime curvature) and of the quantum objects (wave function).The model may be viewed as a derivative of loop quantum gravity, spin networks and causal dynamical triangulation, although significant deviations to these theories exist.The causal model of quantum loops is based on a causal model of spacetime dynamics where space (-time) consists of interconnected space points, each of which is connected to a small number of neighboring space points.The curvature of spacetime is expressed by the density of these space points and by the arrangement of the connections between them.The quantum loop emerges in a collective behavioral process from a collection of space points that carry energy and quantum field attributes.The paper is considered by the author to represent a fairly complete causal model, except for some processes whose detailed behaviour needs to be determined by use of further computer simulations.
Ultimate goal of the work described in this paper has been the construction of a local causal model of quantum theory including quantum field theory.The original model has been refined in a number of refinement steps.As the so far latest refinement step, quantum loops are identified as the elementary processes of spacetime dynamics and quantum field dynamics.Quantum loops are processes that constitute quantum objects.In the causal model of quantum loops and quantum objects presented here, the collective behavioral processes involve the elementary units of spacetime and the associated elementary units of quantum of fields.As such, quantum loop processes are the sources of gravitational fields (i.e., spacetime curvature) and of the quantum objects (wave function).The model may be viewed as a derivative of loop quantum gravity, spin networks and causal dynamical triangulation, although significant deviations to these theories exist.The causal model of quantum loops is based on a causal model of spacetime dynamics where space (-time) consists of interconnected space points, each of which is connected to a small number of neighboring space points.The curvature of spacetime is expressed by the density of these space points and by the arrangement of the connections between them.The quantum loop emerges in a collective behavioral process from a collection of space points that carry energy and quantum field attributes.The paper is considered by the author to represent a fairly complete causal model, except for some processes whose detailed behaviour needs to be determined by use of further computer simulations.
The enterprise to construct a local causal model of quantum theory (QT), including quantum field theory (QFT), resulted in the identification of "quantum objects" as the elementary units of causality and locality.Quantum objects are collections of particles (including single particles) whose collective dynamics and measurement results can only be described by the laws of QT/ QFT.Quantum objects run autonomously with system state update frequency based on their local proper time and with no or minimal dependency on external parameters.The autonomy of quantum objects necessitates well-defined causal interrelationships between quantum objects and spacetime: 1) Quantum objects are embedded in space and move within space.2) In the proposed causal model, the dynamics of space is triggered by the dynamics of the quantum objects.The causal model of QT/QFT assumes discretized spacetime similar to the spacetime of causal dynamical triangulation.
The author's attempt to construct a local causal model of quantum theory (QT) that includes quantum field theory (QFT) resulted in the identification of "quantum objects" as the elementary units of causality and locality. Quantum objects are collections of particles (including single particles) whose collective dynamics and measurement results can only be described by the laws of QT and QFT. Local causal models of quantum objects' internal dynamics are not possible if a locality is understood as a space-point locality. Within quantum objects, state transitions may occur which instantly affect the whole quantum object. The identification of quantum objects as the elementary units of causality and locality has two primary implications for a causal model of quantum objects: (1) quantum objects run autonomously with system-state update frequencies based on their local proper times and with either no or minimal dependency on external parameters. (2) The laws of physics that describe global (but relativistic) interrelationships must be translated to a causal model of interactions between quantum objects and interactions between quantum objects and the space.
Abstract This work develops a process-based framework for quantum gravity in which physical space is rigorously described as the topology of a dynamically evolving graph of discrete quantum processes called P-tacts. A P-tact is defined as the primitive unit of quantum evolution, unifying local superposition and entangling operations into a single indivisible process step. Within this formalism, spacetime is not assumed as a pre-existing background but emerges from the connectivity structure of entanglement relations between P-tacts. The present study synthesizes and extends a coherent research program published throughout 2026. The foundational definition of the P-tact as the primitive unit of quantum theory was introduced in: Pavlov, M. (2026). P Tact (П-такт) as the Primitive Unit of Quantum Theory. Zenodo.https://doi.org/10.5281/zenodo.18516711 The emergence of the quantum switch as a process structure and the reconstruction of indefinite causal order were developed in: Pavlov, M. (2026). Quantum Switch as an Emergent Process Structure from Discrete Process Tacts (П-такт).https://doi.org/10.5281/zenodo.18498181 Pavlov, M. (2026). Indefinite Causal Order as Superposition of Process Graphs.https://doi.org/10.5281/zenodo.18519010 Pavlov, M. (2026). From Indefinite Causal Order to Definite Process Order: A Topological Reconstruction of the Quantum Switch via Discrete P-Tacts (П-такт).https://doi.org/10.5281/zenodo.18526959 Pavlov, M. (2026). Quantum Switch as a Minimal P Tact (П-такт) Cycle.https://doi.org/10.5281/zenodo.18607385 The connection between P-tacts, teleportation, and non-classical causal structures was presented in: Pavlov, M. (2026). Quantum Switch and Teleportation.https://doi.org/10.5281/zenodo.18509173 The emergence of time, causality, gravity, and three-dimensional space from discrete P-tact dynamics was developed in: Pavlov, M. (2026). Emergence of Causality, Gravity, Time, and Three-Dimensional Space from Discrete P-Tact (П-такт) Dynamics.https://doi.org/10.5281/zenodo.18504244 Pavlov, M. (2026). Emergence of Time from P Tact Entanglement (Происхождение времени).https://doi.org/10.5281/zenodo.18526015 Pavlov, M. (2026). Causality and Arrow of Time.https://doi.org/10.5281/zenodo.18549931 The Everett interpretation was explicitly formalized within the P-tact graph framework in: Pavlov, M. (2026). Everett Interpretation Formalized via P-Tact (П-такт) Path Graphs.https://doi.org/10.5281/zenodo.18524745 The present work integrates these results into a unified topological model in which space is identified with graph connectivity, curvature corresponds to dynamic restructuring of entanglement relations, and gravitational phenomena emerge as large-scale patterns of connectivity evolution. In this framework, geometry is not fundamental but process-derived. The theory is fully compatible with Everettian quantum mechanics and eliminates the need for wavefunction collapse. Branching structures correspond to graph bifurcations in the P-tact network, providing a structural representation of many-world dynamics. Gravity is thus interpreted not as a fundamental interaction but as an emergent property of quantum process topology. This approach proposes a formally consistent, unitary, and experimentally testable pathway toward quantum gravity grounded entirely in discrete quantum processes. Potential experimental implementations include quantum simulators and BQM platforms capable of modeling evolving entanglement graphs.
The dissertation investigates some relevant metaphysical issues arising in the context of spacetime theories. In particular, the inquiry focuses on general relativity and canonical quantum gravity. A formal definition of spacetime theory is proposed and, against this framework, an analysis of the notions of general covariance, symmetry and background independence is performed. It is argued that many conceptual issues in general relativity and canonical quantum gravity derive from putting excessive emphasis on general covariance as an ontological prin-ciple. An original metaphysical position grounded in scientific essential- ism and causal realism (weak essentialism) is developed and defended. It is argued that, in the context of general relativity, weak essentialism supports spacetime substantivalism. It is also shown that weak essentialism escapes arguments from metaphysical underdetermination by positing a particular kind of causation, dubbed geometric. The proposed interpretive framework is then applied to Bohmian mechanics, pointing out that weak essentialism nicely fits into this theory. In the end, a possible Bohmian implementation of loop quantum gravity is considered, and such a Bohmian approach is interpreted in a geometric causal fashion. Under this interpretation, Bohmian loop quantum gravity straightforwardly commits us to an ontology of elementary extensions of space whose evolution is described by a non-local law. The causal mechanism underlying this evolution clarifies many conceptual issues related to the emergence of classical spacetime from the quantum regime. Although there is as yet no fully worked out physical theory of quantum gravity, it is argued that the proposed approach sets up a standard that proposals for a serious ontology in this field should meet.
An explanation for quantum mechanics is given in terms of a classical theory (general relativity) for the first time. Specifically, it is shown that certain structures in classical general relativity can give rise to the non-classical logic normally associated with quantum mechanics. An artificial classical model of quantum logic is constructed to show how the Hilbert space structure of quantum mechanics is a natural way to describe a measurement-dependent stochastic process. A 4-geon model of an elementary particle is proposed which is asymptotically flat, particle-like and has a non-trivial causal structure. The usual Cauchy data are no longer sufficient to determine a unique evolution; the measurement apparatus itself can impose further non-redundant boundary conditions. When measurements of an object provide additional non-redundant boundary conditions, the associated propositions would fail to satisfy the distributive law of classical physics. Using the 4-geon model, an orthomodular lattice of propositions, characteristic of quantum mechanics, is formally constructed within the framework of classical general relativity. The model described provides a classical gravitational basis for quantum mechanics, obviating the need for quantum gravity. The equations of quantum mechanics are unmodified, but quantum behaviour is not universal; classical particles and waves could exist and there is no graviton.
Quantum mechanics has achieved unparalleled success as an operational theory, describing a wide range of experiments to remarkable accuracy. However, the physical foundations on which it rests remain as puzzling as they were a century ago, and a concise statement of the physical principles that underlie quantum mechanics is still outstanding. One promising approach holds that these principles should be formulated in terms of information, since many of the counter-intuitive effects in quantum theory concern questions such as what one can know about a quantum system and how the information encoded therein can be processed and distributed between parties. Another challenging feature of quantum theory is its incompatibility with the other cornerstone of modern physics, general relativity. In order to reconcile the two, one must identify and retain only the essential concepts and principles of each theory, and in the case of general relativity, causality has been identified as such a concept. This raises the question of how our classical understanding of causality must change when quantum theory is taken into account. In order to address these questions about information, knowledge and causality, I turn to the framework of causal models. In classical statistics, causal models explain the relations among a set of variables in terms of causal influences, which makes them a powerful tool for structuring our knowledge about complex systems and developing strategies for interacting with them. More importantly, the framework provides the conceptual underpinnings and mathematical methods for addressing questions about causation, information and knowledge in a rigorous manner. In this thesis, I develop a version of the classical causal models framework that is compatible with quantum theory and explore its physical implications. \n \n \nA first step is to define quantum versions of fundamental elements such as variables, conditionals and belief propagation rules. This allows one to consider the question of what one can come to know about a quantum variable from the point of view of causal modelling. The conditionals relating quantum variables are found to have a richer structure than their classical counterparts, which can be exploited for the task of discerning causal relations given limited data -- a central problem in classical causal modelling. The mathematical properties of quantum conditionals also establish a correspondence between various classes of two-party correlations, such as bound and distillable entanglement, and the types of causal structures that can give rise to them, which may become a useful tool for entanglement theory and quantum information processing. In the context of open quantum systems dynamics, quantum causal models provide a clear physical explanation of not completely positive maps and, more broadly, of non-Markovian quantum dynamics. Finally, I consider the possibility of non-classical effects in the way that different causal mechanisms are combined -- that is, non-classical causal structures. For the simple case of two causally ordered variables, I propose indicators that witness different classes of combinations of causal mechanisms, including a non-classical mixture, and describe an experiment realizing examples of the different classes. \n \n \nAs these results illustrate, the framework of quantum causal models provides both greater conceptual clarity and a comprehensive mathematical formalism for studying a diverse set of problems, ranging from foundational questions to applications in open systems dynamics and the exploration of non-classical causal structures, which are likely to feature in a future theory of quantum gravity. The material presented in this thesis is intended as a foundation and inspiration for further applications of quantum causal models.