For a free spinless non-relativistic particle, an invariance principle of Heisenberg inequality explains all quantum postulates and reveals a dual quantum dynamics
Abstract For a free non-relativistic particule, the postulates of quantum mechanics are derived from classical mechanics by imposing a single one. It states that the Heisenberg inequality is fundamental and invariant under a group of special nonlinear gauge transformations (NLGT) with real group parameter. Imposing this postulate to classical mechanics with random initial positions generates a twin dynamical structure: one is the standard unitary quantum evolution. The other is not unitary. The two dynamics tightly intertwine under a NLGT. Moreover, the new dynamics and the unitary evolution are directly mapped one into the other by a NLGT with imaginary parameter. This mapping reveals that the novel dynamics is a Schrödinger bridge process (SBP), a classical random process that naturally involves the Born rule. Any solution admitted by a SBP requires both an initial and a final condition and its evolution parameter is structurally analogous to a space-like dimension, different of the usual time and revealing a process that is non causal in nature. Remarkably, this evolution parameter and the usual unitary time form a two-dimensional Minkowski space. The SBP provides a possible description of the collapse of the wave-function during a measurement. A functional Lie-algebra framework is used and is an essential mathematical tool for the presented theory.
Abstract For a free non-relativistic particule, the postulates of quantum mechanics are derived from classical mechanics by imposing a single one. It states that the Heisenberg inequality is fundamental and invariant under a group of special nonlinear gauge transformations (NLGT) with real group parameter. Imposing this postulate to classical mechanics with random initial positions generates a twin dynamical structure: one is the standard unitary quantum evolution. The other is not unitary. The two dynamics tightly intertwine under a NLGT. Moreover, the new dynamics and the unitary evolution are directly mapped one into the other by a NLGT with imaginary parameter. This mapping reveals that the novel dynamics is a Schrödinger bridge process (SBP), a classical random process that naturally involves the Born rule. Any solution admitted by a SBP requires both an initial and a final condition and its evolution parameter is structurally analogous to a space-like dimension, different of the usual time and revealing a process that is non causal in nature. Remarkably, this evolution parameter and the usual unitary time form a two-dimensional Minkowski space. The SBP provides a possible description of the collapse of the wave-function during a measurement. A functional Lie-algebra framework is used and is an essential mathematical tool for the presented theory.
A unique postulate is shown to underly the whole quantum mechanics theory: the invariance of the Heisenberg uncertainty inequality under a group of special nonlinear gauge transformations (NLGT). With this postulate, the quantum mechanics of a free particle is derived from classical mechanics, including the statements of the postulates of quantum mechanics, except for the wave-function-collapse postulate. An explanatory mechanism for the latter postulate is derived by performing an analytical continuation of the NLGTs. This extension results in a Schrödinger-bridge process, intertwined under the NLGT with the standard unitary quantum evolution, and revealing non-quantum (or beyond-quantum) phenomena. Mechanisms of that latter kind, like the ones associated to the quantum measurement process, occur in a new space-like dimension and hence are non causal in nature, in opposition to a time evolution. The present exercice focusses on the free particle in order to highlight the features of the performed derivation in the simplest possible way. Work is in progress to extend the performed derivation beyond that simple case.
Non-relativistic quantum mechanics for a free particle is shown to emerge from classical mechanics through an invariance principle under transformations that preserve the Heisenberg position–momentum inequality. These transformations are induced by isotropic space dilations. This invariance imposes a change in the laws of classical mechanics that exactly corresponds to the transition-to-quantum mechanics. The Schrödinger equation appears jointly with a second nonlinear equation describing non-unitary processes. Unitary and non-unitary evolutions are exclusive and appear sequentially in time. The non-unitary equation admits solutions that seem to correspond to the collapse of the wavefunction.
This paper derives the non-relativistic time-dependent Schrödinger equation as the logically unavoidable dynamical law for de Broglie matter waves, extending the reconstruction begun in the companion work “The Logical Origin of the de Broglie Matter Wave and its Physical Meaning (the Born Rule)” (Chan, 2026). Starting from the same minimal premises—continuous position in real space, Fourier conjugacy (and the logical uncertainty principle), translation invariance via Noether’s theorem, and probability conservation via statistical energy flux—the Schrödinger equation follows deductively once norm preservation and classical non-relativistic correspondence are enforced. The derivation proceeds in clear stages: Plane-wave solutions for free particles and constant potentials, Quadratic dispersion relation from classical kinematics, Exact local plane-wave structure (defined via phase gradients) that must hold at every point for any smooth wave function, The unique linear differential operator of order ≤ 2 that consistently “glues” these local structures across smooth external potentials V(x,t) while preserving the L²-norm (unitarity). No canonical quantization, operator promotion, commutation relations, or postulated wave equations are used. The Born rule is taken as already established from the prior paper and serves only to constrain unitary evolution. The Schrödinger equation thus emerges not as an empirical postulate or convenient ansatz, but as the mathematically and symmetrically forced description of indivisible particles propagating in continuous, translationally invariant (or smoothly perturbed) space. Domain of validity and natural limitations (non-relativistic kinematics, smooth potentials, single-particle/mean-field regime, closed-system unitarity) are explicitly delineated.
Standard quantum mechanics relies on two distinct dynamical principles: unitary evolution and collapse. A mathematically self-contained variational framework is presented that replaces this dualism with a single principle, in which nonrelativistic Schrödinger dynamics are not postulated but emerge as an admissible optimality condition of a primal-dual boundary-value problem. By expressing the state in terms of hydrodynamic variables (ρ,j) subject to a continuity constraint, it is shown that Fisher-information regularization yields the linear Schrödinger equation within the admissible single-valued variational class. Rather than evolving an initial state forward in time, the dynamics arise from minimizing a global action that connects the initial and final boundary constraints, with the selected solution corresponding to a specific hydrodynamic flow within an ensemble of admissible histories. A von Neumann pointer model illustrates how Born-rule statistics for recorded outcomes arise without introducing a separate collapse law. Within this formulation, quantum uncertainty is interpreted as effective randomness over boundary-compatible histories rather than as a fundamental stochastic postulate. The resulting framework provides a nonrelativistic proof of concept for how a single time-symmetric variational reformulation can recover key features of quantum theory.
Non-relativistic quantum mechanics is shown to emerge from classical mechanics through the requirement of a relativity principle based on special transformations acting on position and momentum uncertainties. These transformations keep the Heisenberg inequalities invariant and form a group. They are related to dilatations of space variables provided the quantum potential is added to the classical Hamiltonian functional. The Schrödinger equation appears to have a nonunitary and nonlinear companion acting in another time variable. Evolution in this time seems related to the state vector reduction.
In this work, we introduce a novel framework for quantum dynamics based on a second-order evolution equation, ∂2/∂t2∣Ψ⟩=K∣Ψ⟩ , with K=i(αD+βV) , where the operators D and V satisfy the Heisenberg algebra [D,V]=dI in d -dimensional space. Unlike conventional quantum mechanics governed by the first-order Schrödinger equation, this formulation emerges from a unified dynamical structure rooted in phase-space symmetry, naturally accommodating non-Hermitian interactions while preserving unitary evolution through the introduction of an η -inner product and a dual-state mapping. We demonstrate that this theory shares an SL(2,R) symmetry with the standard quantum formalism, revealing that both the Schrödinger and our second-order dynamics arise as distinct realizations within the same symplectic framework — the former as a quadratic generator (energy conservation), the latter as a linear generator (driving-dissipation balance). Extending the theory to four dimensions via Dirac matrices yields a covariant, spinor-valued wave equation whose stationary solutions carry instanton topological charge, π3(S3)=Z , thereby unifying the topological structures from one to four spatial dimensions under the homotopy classification πd−1(Sd−1)=Z . This approach not only generalizes non-Hermitian quantum mechanics beyond PT -symmetric potentials but also establishes a direct bridge between quantum dynamics, symplectic geometry, and topological field theory.