Distant correlation experiments with identical fermions (e.g. protons, as in the work of Lamehi-Rachti and Mittig 1976) require a theory which includes the Pauli principle. This fact makes an immediate application of the usual quantum mechanical distant correlation theories impossible, because the exclusion principle precludes the interpretation of particles as subsystems. Utilising the fact that the measuring apparata (for one-particle measurements) are in two non-overlapping spatial regions, it is shown that there exists a mapping preserving all the relevant physical information that allows a transformation to a distinct-particle picture, in which the particles can be naturally treated as subsystems, and the relevant observables have the usual simple form. It is argued that, due to the existence of this mapping, the Pauli non-local correlations do not contribute to distant correlations between identical fermions. A negentropy measure of distant correlations is introduced and discussed. It is demonstrated that they are necessarily of dynamical origin.
Distant correlation experiments with identical fermions (e.g. protons, as in the work of Lamehi-Rachti and Mittig 1976) require a theory which includes the Pauli principle. This fact makes an immediate application of the usual quantum mechanical distant correlation theories impossible, because the exclusion principle precludes the interpretation of particles as subsystems. Utilising the fact that the measuring apparata (for one-particle measurements) are in two non-overlapping spatial regions, it is shown that there exists a mapping preserving all the relevant physical information that allows a transformation to a distinct-particle picture, in which the particles can be naturally treated as subsystems, and the relevant observables have the usual simple form. It is argued that, due to the existence of this mapping, the Pauli non-local correlations do not contribute to distant correlations between identical fermions. A negentropy measure of distant correlations is introduced and discussed. It is demonstrated that they are necessarily of dynamical origin.
Pauli's exclusion principle has a strong impact on the properties of most fermionic quantum systems. Remarkably, the fermionic exchange symmetry implies further constraints on the one-particle picture. By exploiting those generalized Pauli constraints, we derive a measure which quantifies the influence of the exchange symmetry beyond Pauli's exclusion principle. It is based on a geometric hierarchy induced by the exclusion principle constraints. We provide a proof of principle by applying our measure to a simple model. In that way, we conclusively confirm the physical relevance of the generalized Pauli constraints and show that the fermionic exchange symmetry can have an influence on the one-particle picture beyond Pauli's exclusion principle. Our findings provide a perspective on fermionic multipartite correlation since our measure allows one to distinguish between static and dynamic correlations.
Usually fermions and bosons behave very differently. Regarding distinguishability, they behave in one and the same way. Two-identical-particle quantum theory is discussed on the example of the deuteron and that of distant correlations, as well as on the example of the real interference and quantum erasure experiments in the Hong–Ou–Mandel two-photon interferometer (with and without polarizers and analyzers). Distinguishability and indistinguishability of two identical photons in the experiments are illustrated. It is demonstrated, using a simple formalism valid simultaneously for fermions and for bosons, that there exists an isomorphism giving theoretical foundation to distinguishing two identical particles. But the distinguishing has a limited range of exact applicability. In most cases of interest, only the indistinguishability approach has a first-principle (and universal) validity.
Abstract “What are the consequences… that Fermi particles cannot get into the same state…” R. P. Feynman wrote of the Pauli exclusion principle, “In fact, almost all the peculiarities of the material world hinge on this wonderful fact.” In 1972 Borland and Dennis showed that there exist powerful constraints beyond the Pauli exclusion principle on the orbital occupations of Fermi particles, providing important restrictions on quantum correlation and entanglement. Here we use computations on quantum computers to experimentally verify the existence of these additional constraints. Quantum many-fermion states are randomly prepared on the quantum computer and tested for constraint violations. Measurements show no violation and confirm the generalized Pauli exclusion principle with an error of one part in one quintillion.
The Pauli exclusion principle is one of the fundamental laws of modern physics. It determines the structure of atoms, the stability of matter, the properties of fermionic systems, and macroscopic phenomena ranging from chemistry to astrophysics. In standard quantum mechanics (QM), this principle is formulated as an axiom of antisymmetry: the wave function of two fermions must change sign under the exchange of coordinates. However, the origin of this antisymmetry remains unexplained within QM itself. Within ZEBTS — the Law of Unity of Being of the Triune Substance — the Pauli principle acquires a geometric and topological foundation. In this ontology, fermions are not treated as elementary particles but as topological modes of the operator metric, arising from the spectral structure of quantum geometry. Antisymmetry and the prohibition of identical states emerge as consequences of: the non‑commutativity of the operator metric, the topological charge λ, the spectral non‑intersection of eigenvalues, holographic constraints on information density. Thus, ZEBTS derives the Pauli principle as a topological law of quantum geometry, rather than a postulate.
The Pauli exclusion principle is traditionally introduced in quantum mechanics as a postulate encoded in the antisymmetry of the fermionic wavefunction. While extraordinarily successful, this formulation leaves open a deeper question: why must nature forbid the perfect overlap of identical fermions? In this work, we propose a reinterpretation of Pauli exclusion within the framework of Viscous Time Theory (VTT), where physical law emerges from the geometry of informational state space under constraints of memory, recoverability, and causal trace preservation. We propose that the coincidence of two identical fermionic states can be interpreted, in informational-geometric terms, as a loss of injectivity of the causal mapping, i.e., to an informational singularity where distinct histories become non-separable. To prevent this collapse of recoverability, the joint state manifold naturally develops a “diagonal barrier”: a forbidden submanifold where the informational cost diverges and admissible trajectories are repelled. Within this perspective, antisymmetry of the wavefunction appears not as the cause of exclusion, but as its mathematical symptom. Within this perspective, Pauli exclusion can be interpreted as a geometric and informational constraint rather than a primitive quantum axiom. The framework further suggests a unified interpretation of the difference between fermions and bosons: the former may be viewed as carriers of identity-bearing, non-overwritable informational structure, while the latter correspond to additive excitations that do not threaten causal injectivity. In this way, the exclusion principle appears as a consequence of informational geometry in a universe characterized by viscous time and memory.
A composite quantum system consisting of two distant subsystems and described by a correlated state vector φ12 is considered. It was shown in a previous work by the authors [Ann. Phys. 96, 382 (1976)] that such a system can be equivalently described in terms of the reduced statistical operators ρ1 and ρ2 of φ12 applying to the subsystems and a correlation operator Ua between them. It is argued that this description has a firm physical foundation for the system considered in view of the fact that, on account of the subsystems being distant, one can only measure pairs of subsystem observables A1, B2 in coincidence. The direct measurement of A1 such that [A1,ρ1]=0 on the ensemble of first subsystems performs distantly (without interaction) an orthogonal decomposition of the ensemble of second subsystems ρ2, that amounts to the measurement of the twin observable A2 (A2≡UaA1U−1aQ2, Q2 being the range projector of ρ2). A number of coincidence experiments have confirmed this claim, and have disproved all attempts (on the quantum and on the subquantum levels) to view this decomposition of ρ2 as being present also before the measurement of A1. Hence, this decomposition into subensembles comes about in the very measurement of A1, and Ua determines them in a simple way. It is demonstrated that Ua is essential for twin observables and twin symmetry operators. A detailed study of these operators is presented from a unified point of view. Puzzling features of quantum correlations described by Ua show up in composite states when the mentioned distant decompositions of ρ2 into subensembles can be incompatible with one another. A general definition of such φEPR12 states (called Einstein–Podolsky–Rosen states) is given in a few equivalent forms, and the nonuniqueness of the Schmidt canonical form of φEPR12 is investigated in order to encourage further theoretical and experimental exploration of distant quantum correlations.