Developing an earlier proposal (Ne'eman, Damnjanovic, etc), we show herein that there is a Landau continuous phase transition from the exact quantum dynamics to the effectively classical one, occurring via spontaneous superposition breaking (effective hiding), as a special case of the corresponding general formalism (Bernstein). Critical values of the order parameters for this transition are determined by Heisenberg's indeterminacy relations, change continuously, and are in excellent agreement with the recent and remarkable experiments with Bose condensation. It is also shown that such a phase transition can sucessfully model self-collapse (self-decoherence), as an effective classical phenomenon, on the measurement device. This then induces a relative collapse (relative decoherence) as an effective quantum phenomenon on the measured quantum object by measurement. We demonstrate this (including the case of Bose-Einstein condensation) in the well-known cases of the Stern-Gerlach spin measurement, Bell's inequality and the recently discussed quantum superposition on a mirror a la Marshall et al. These results provide for a proof that quantum mechanics, in distinction to all absolute collapse and hidden-variable theories, is local and objective. There now appear no insuperable obstacles to solving the open problems in quantum theory of measurement and foundation of quantum mechanics, and strictly within the standard quantum-mechanical formalism. Simply put, quantum mechanics is a field theory over the Hilbert space, the classical mechanics characteristics of which emerge through spontaneous superposition breaking.
Developing an earlier proposal (Ne'eman, Damnjanovic, etc), we show herein that there is a Landau continuous phase transition from the exact quantum dynamics to the effectively classical one, occurring via spontaneous superposition breaking (effective hiding), as a special case of the corresponding general formalism (Bernstein). Critical values of the order parameters for this transition are determined by Heisenberg's indeterminacy relations, change continuously, and are in excellent agreement with the recent and remarkable experiments with Bose condensation. It is also shown that such a phase transition can sucessfully model self-collapse (self-decoherence), as an effective classical phenomenon, on the measurement device. This then induces a relative collapse (relative decoherence) as an effective quantum phenomenon on the measured quantum object by measurement. We demonstrate this (including the case of Bose-Einstein condensation) in the well-known cases of the Stern-Gerlach spin measurement, Bell's inequality and the recently discussed quantum superposition on a mirror a la Marshall et al. These results provide for a proof that quantum mechanics, in distinction to all absolute collapse and hidden-variable theories, is local and objective. There now appear no insuperable obstacles to solving the open problems in quantum theory of measurement and foundation of quantum mechanics, and strictly within the standard quantum-mechanical formalism. Simply put, quantum mechanics is a field theory over the Hilbert space, the classical mechanics characteristics of which emerge through spontaneous superposition breaking.
In this work spontaneous (non-dynamical) breaking (effective hiding) of the unitary quantum mechanical dynamical symmetry (superposition) is considered. It represents an especial but very interesting case of the general formalism of the spontaneous symmetry breaking (effective hiding). Conceptual analogies with spontaneous breaking of the gauge symmetry in Weinberg-Sallam's electro-weak interaction are pointed out. Also, consequences of the spontaneous superposition breaking in the measurement process are discussed. Measurement can be considered as a typical Landau's continuous phase transition with spontaneous superposition breaking (effective hiding) effectively corresponding to collapse. Here critical values of the order parameters are determined by Heisenberg's uncertainty relations.
Abstract The quantum measurement problem—the absence of any dynamical mechanism connecting continuous wavefunction evolution to discrete empirical outcomes—has persisted since the foundations of quantum theory. Decoherence explains interference suppression but cannot explain outcome selection: the diagonal density matrix remains an improper mixture until one outcome is actualized. We propose that collapse is a physical phase transition in the coupled system–apparatus field. The order parameter ψ, constructed as a coarse-grained collective coordinate of apparatus degrees of freedom, evolves under Ginzburg–Landau dynamicswith a symmetry-breaking potential. When the coherence pressure γ exceeds a critical threshold γc, the symmetric phase(superposition) becomes unstable and the field crystallizes into one of the discrete stable minima (eigenstates). We derive the critical coupling from microscopic system–apparatus Hamiltonians, obtaining γc ∼ (√Ng)−1 where N is the number of apparatus degrees of freedom and g is the coupling constant. This scaling explains why macroscopic apparatus collapse wavefunctions while microscopic interactions preserve coherence. The Born rule Pn = |cn|2 is preserved through this dynamical selection mechanism: attractor basin geometry under probability-conserving flow converts probabilistic weights into definite outcomes without altering the underlying probabilities. The theory yields four falsifiable predictions absent from standard quantum mechanics: critical slowing near γc, hysteresis in the collapse–recoherence cycle, metastable supercooled superpositions, and transient Jacobian spikes at the moment of collapse. We provide quantitative estimates for superconducting qubit readout, predicting collapsetimes of order 100 ns with critical slowing observable within current experimental precision. This framework provides a concrete existence proof, within a controlled effective-theory regime, that collapse dynamics can be constructed from standard quantum mechanics plus statistical mechanics, requiring no modification to the Schr¨odinger equation.
The quantum measurement problem remains one of the most profound unresolved issues in fundamental physics. While quantum mechanics delivers extraordinarily precise statistical predictions, it does not specify a physical mechanism by which definite classical outcomes arise from quantum superpositions. Decoherence theory accounts for the suppression of interference but does not explain outcome selection or the stability of classical reality. This paper investigates quantum measurement within the framework of Relativistic Coherent Vacuum Gravity Theory (rCVGT). In rCVGT, the vacuum is modeled as a structured relativistic medium characterized by a coherence order parameter ψ(x), a coherence magnitude Q(x) = |ψ(x)|², a vacuum-flow four-field u^μ(x), and a physical time-rate field τ(x). We propose that quantum measurement corresponds to a dynamical instability of vacuum coherence induced by macroscopic coupling to matter and radiation. Classical outcomes emerge when local vacuum coherence is driven below a critical stability threshold, resulting in an irreversible reconfiguration of the vacuum state. The collapse timescale is determined by the vacuum-coherence self-energy defined within rCVGT. This mechanism simultaneously provides a physical foundation for classicality, irreversibility, and the arrow of time. The framework preserves the formal structure and empirical predictions of quantum mechanics while offering a unified physical explanation of measurement grounded in relativistic vacuum dynamics.
Abstract This article presents a revised and conceptually refined formulation of a previously proposed Temporal Interpretation of quantum measurement, explicitly addressing the physical nature of wavefunction collapse. While the original proposal emphasised relativistic aspects of momentum superpositions, the present work clarifies the interpretation within the standard formalism of quantum mechanics, without introducing new dynamics or experimental predictions. Unitary evolution is read as a process of differentiated phase accumulation between branches of a quantum state. In relativistic contexts, phase differentials can be structurally related to effective proper-time differentials, allowing the introduction of a notion of temporal compatibility that provides a physically grounded account of decoherence. When such differentials exceed a characteristic scale, interference between branches becomes operationally inaccessible, while global unitarity is preserved. The observer is treated as a physical system endowed with an irreversible proper time associated with macroscopic, entropic dynamics. Within this framework, collapse is explained as an emergent physical phenomenon arising from the irreversibility of the observer’s proper time, which prevents the reconstruction of phase coherence after an interaction. Collapse is therefore neither a fundamental dynamical mechanism nor an objective event in space-time, but a necessary consequence of temporal irreversibility in physical observers. This formulation sharpens the distinction between decoherence and collapse, preserves full consistency with the Born rule, and positions the Temporal Interpretation as a competing interpretative framework that provides a concrete physical explanation for the quantum–classical transition, improving and clarifying the original proposal. This version clarifies the operational status of the interaction time, refines Sections 5.3 and 5.4, and standardises references and editorial structure. No changes to the formalism or conclusions.
A model of quantum measurement is proposed, which aims to describe statistical mechanical aspects of this phenomenon, starting from a purely Hamiltonian formulation. The macroscopic measurement apparatus is modeled as an ideal Bose gas, the order parameter of which, that is, the amplitude of the condensate, is the pointer variable. It is shown that properties of irreversibility and ergodicity breaking, which are inherent in the model apparatus, ensure the appearance of definite results of the measurement, and provide a dynamical realization of wave-function reduction or collapse. The measurement process takes place in two steps: First, the reduction of the state of the tested system occurs over a time of order $\ensuremath{\Elzxh}{/(TN}^{1/4}),$ where T is the temperature of the apparatus, and N is the number of its degrees of freedom. This decoherence process is governed by the apparatus-system interaction. During the second step classical correlations are established between the apparatus and the tested system over the much longer time scale of equilibration of the apparatus. The influence of the parameters of the model on nonideality of the measurement is discussed. Schr\"odinger kittens, EPR setups, and information transfer are analyzed.
This thesis presents a comprehensive study of phase-space measurements, decoherence, and the emergence of classicality in quantum systems. Motivated by limitations of position-based localisation in standard decoherence models, we develop a phase-space decoherence formalism using coherent-state positive operator-valued measures (POVMs). These generalised measurements, constructed from overcomplete sets of coherent states, provide a natural and physically motivated framework for modelling coarse-grained quantum observations. We develop an iterative measurement scheme for phase-space decoherence in systems with Heisenberg-Weyl, SU(2), SU(1,1), and SU(N) symmetries. In each case, repeated weak measurements gradually suppress quantum interference, driving the system toward a maximally mixed state. A universal structure is shown to emerge: a single iteration maps the Wigner function to the Husimi Q-function, removing negativity, while full decoherence maps the singular Glauber-Sudarshan P-function to the Q-function, eliminating all singularities. This establishes a group-independent mechanism by which phase-space measurements induce classicality. We compare this model to Lindblad-type dynamics, which describe open quantum systems via completely positive, trace-preserving semigroups. For Heisenberg-Weyl and tomographic SU(N) systems, the measurement channel coincides exactly with isotropic Lindblad evolution. In SU(2) and SU(1,1) cases, the correspondence is only partial, with exact agreement in asymptotic regimes. A universal decoherence timescale, t∗, emerges beyond which quasi-probability distributions become strictly positive. We then construct a stochastic unravelling based on Brownian motion on phase space, offering a geometric alternative to standard stochastic Schr\"odinger equations. This reveals that decoherence occurs without GKSL-type dynamics in noncompact systems. Such unravellings preserve the intrinsic phase-space symmetry and provide a natural setting for studying semiclassical limits and quantum-to-classical transitions. Finally, we extend the framework to relativistic quantum systems by defining a covariant coherent-state POVM on the future tube and constructing a Bargmann transform to the forward light cone. Preliminary results on relativistic phase-space decoherence are presented, along with possible directions for future research.