Although the standard viewpoint in theoretical physics is that the unification of quantum theory and general relativity requires the quantization of gravity and spacetime, there is not consensus about whether spacetime must fundamentally have any quantum features. Here we show a theorem stating that spacetime degrees of freedom and a quantum system violate a Bell inequality in a background Minkowski spacetime if a few properties of general relativity and quantum theory have a broad range of validity, and if the quantum state reduction upon measurement is a real physical process that is completed superluminally when acting on distant quantum particles in a quantum entangled state. We argue that this implies that spacetime cannot be sensibly called classical if the assumptions in our theorem hold. In contrast to the Eppley-Hannah argument for the necessity of quantizing the gravitational field, we discuss the validity of our assumptions, our thought experiment does not require to manipulate or detect gravitational waves, and our theorem does not rely on the conservation of momentum or on the uncertainty principle.
Although the standard viewpoint in theoretical physics is that the unification of quantum theory and general relativity requires the quantization of gravity and spacetime, there is not consensus about whether spacetime must fundamentally have any quantum features. Here we show a theorem stating that spacetime degrees of freedom and a quantum system violate a Bell inequality in a background Minkowski spacetime if a few properties of general relativity and quantum theory have a broad range of validity, and if the quantum state reduction upon measurement is a real physical process that is completed superluminally when acting on distant quantum particles in a quantum entangled state. We argue that this implies that spacetime cannot be sensibly called classical if the assumptions in our theorem hold. In contrast to the Eppley-Hannah argument for the necessity of quantizing the gravitational field, we discuss the validity of our assumptions, our thought experiment does not require to manipulate or detect gravitational waves, and our theorem does not rely on the conservation of momentum or on the uncertainty principle.
In modern quantum information theory one deals with an idealized situation when the spacetime dependence of quantum phenomena is neglected. However the transmission and processing of (quantum) information is a physical process in spacetime. Therefore such basic notions in quantum information theory as qubit, channel, composite systems and entangled states should be formulated in space and time. In this paper some basic notions of quantum information theory are considered from the point of view of quantum field theory and general relativity. It is pointed out an important fact that in quantum field theory there is a statistical dependence between two regions in spacetime even if they are spacelike separated. A classical probabilistic representation for a family of correlation functions in quantum field theory is obtained. A noncommutative generalization of von Neumann`s spectral theorem is discussed. We suggest a new physical principle describing a relation between the mathematical formalism of Hilbert space and quantum physical phenomena which goes beyond the superselection rules. Entangled states and the change of state associated with the measurement process in space and time are discussed including the black hole and the cosmological spacetime. It is shown that any reasonable state in relativistic quantum field theory becomes disentangled at large spacelike distances if one makes local observations. As a result a violation of Bell`s inequalities can be observed without inconsistency with principles of relativistic quantum theory only if the distance between detectors is rather small. We suggest a further experimental study of entangled states in spacetime by studying the dependence of the correlation functions on the distance between detectors.
This paper examines the history of Bell’s inequality from EPR argument to Bell’s papers, and the influence of Bell’s inequality on the frontier exploration of quantum mechanics. It is found that Bell’s inequality has some hidden assumptions that are different from EPR argument. Along Schrodinger’s idea that the measurement process of the EPR experiment requires time, Karl Hess and his follows treat time as a time order parameter, by extending the method of space-time geometry analysis of relativity to the localized geometry analysis of quantum states, it is believed that the reasoning of Bell’s inequality does not meet the requirements of the completeness of EPR argument. Analyzing the non locality of gravitational energy in general relativity makes it necessary for us to seek a more localized expression of relativistic gravitational theory. Based on local realism, exploring new interpretations and expressions of quantum mechanics may open up new avenues for studying quantum gravity. We found that Lorentz almost discovered the incompleteness of general relativity but erroneously insisted on the concepts of ether and absolute space, just as Einstein correctly discovered the flaws in the non local representation of quantum mechanics based on outdated determinism.
The state-of-the-art physics consists of two irreconcilable branches, i.e., the quantum theory and the general relativity, which work well in their own territories, independently. However, what are quantum and spacetime after all? The key question was never addressed, satisfactorily. In this work, we describe a possibility to reformulate the quantum theory in the Minkowski spacetime from the viewpoint of classic physics in the Euclidean spacetime, i.e., classic mechanics and stochastic process theory. We show that quantum theory and Minkowski spacetime may connect with each other and emerge from a single fundamental entity.
In this paper, we study implications of the geometrical nature of space- time for some of the basic tenets of quantum mechanics. That is, we study two different implications of the principle of general covariance; first we quantize a reparametrization invariant theory, the free particle in Minkowski spacetime and point out in detail where this theory fails (no- tably these comments appear to be missing in the literature). Second we study the covariance of quantum field theory and show how it connects to causality, the outcome of this study is that QFT is what we shall call ultra weakly covariant with respect to the background spacetime. Third, we treat the question of whether evolution in quantum theory (apart from the measurement act) needs to be unitary, it is easily shown that a per- fectly satisfying probabilistic interpretation exists which does not require unitary evolution. Fourth, we speculate on some modifications quantum theory should undergo in order for it to be generally covariant. The results in this paper hint at a profound change of the theory in which causality as a fundamental principle is abandonned.
This paper unifies quantum mechanics with time field theory in flat spacetime. Starting from the linear wave equation of the time field γ, we rigorously derive the Schrödinger equation as the nonrelativistic limit of time field oscillations. Quantum entanglement and the Bell inequality are explained by global phase synchronization of the time field, without hidden variables or superluminal nonlocality. Spin-1/2 particles and photon polarization are consistently described. This work completes the unification of gravity, spacetime geometry, and quantum mechanics within a single, self-consistent, singularity-free framework.
Standard quantum mechanics requires six independent axioms of the Copenhagen interpretation, all formulated in a non-relativistic framework lacking Lorentz invariance and thus fundamentally inconsistent with Minkowski spacetime. This paper argues that the measurement problem, wave-function collapse, Schrödinger's cat, and the non-locality of entanglement share a common root: non-relativistic quantum mechanics is an approximation of a more fundamental theory, and interpretations built upon an approximation cannot be fully correct. We propose Spacetime Wave Quantum Theory (SWQ theory), which takes Minkowski spacetime as its sole geometric premise and proceeds from two axioms: Axiom 1 (Quantum nature): A quantum exists in spacetime with finite extent and behaves as a wave whose action changes only in discrete multiples of h. Axiom 2 (Superposition principle): Superposition on multiple paths holds if and only if no difference arises in the state of external quanta between those paths — a purely physical condition with no role for observer consciousness. From these two axioms, the Klein–Gordon and Dirac equations are derived directly, with the Schrödinger equation recovered as their non-relativistic limit. The six Copenhagen axioms are replaced by two. Central concept — the Spacetime Action Packet (SAP): Every quantum occupies a finite four-dimensional spacetime region. For energy E, the temporal thickness satisfies Δt ≳ h/E. The SAP has a minimum size but no upper bound; quantum interactions are described as overlap integrals over the spacetime volume where two SAPs coincide. A key consequence is that different quanta — including three quarks inside a nucleon and neutrinos traversing the Earth — can occupy the same spacetime region without restriction; the Pauli exclusion principle applies only to identical fermions in identical states. Principal results of v2.0: Wave-function collapse is dissolved as the physical end and beginning of a quantum wave (wave-terminating interaction); the projection postulate is unnecessary. Feynman spacetime integration and virtual particles acquire a natural physical basis; finite SAP size provides an intrinsic UV cutoff without renormalization. Zero-point energy (ħω/2) is diagnosed as an artifact of operator ordering in quantization — not a physical entity — rendering the cosmological constant problem a structural consequence of summing a quantity that was never real. A first-order extension to a-ECG curved spacetime shows that gravitational redshift, gravitational mass deficit, and the increase in SAP temporal thickness all scale as √A(r), unifying classical and quantum descriptions of energy conservation under gravity. These results are supported by quantitative tests obtained without renormalization: the electron anomalous magnetic moment ae = α/2π (1-loop) and 2-loop coefficient C4 to 0.0015%; the Compton cross-section to within 0.07% of the Klein–Nishina formula; and nucleon magnetic moments to ∼1.5%. Details appear in the series papers on the Rotating Spinor Wave (RSW) model. Series context: SWQ theory forms the foundational framework for the RSW model (unified description of fermion spin, g-factors, and hadron mass spectra) and the Energy-Conserving Gravity theory (a-ECG, a modification of general relativity incorporating full energy-momentum conservation). These three papers constitute an interconnected series. Note: Generative AI tools (Claude Sonnet 4.6, Anthropic; Grok, xAI) were used for drafting and language checking. All scientific content and responsibility rest solely with the author.