arXiv subjects

Carmine De Rosa

Publications and source records attributed to Carmine De Rosa.

3 recordsLinked to original sources

arXiv2026

Representation of the causal logic for the Dirac system and the electron

We construct a covariant representation of the causal logic for the Dirac system and the electron, based on the conserved Dirac probability current and a general current-to-localization procedure for achronal regions. A polynomial decay estimate, derived by a non-stationary phase argument, verifies the conditions required to define covariant achronal localization for the full Dirac system. Extending this localization to complete spacetime regions yields the corresponding causal-logic representation; restriction to the positive-energy invariant subspace gives the analogous construction for the electron. We establish several structural properties. On Euclidean space, Dirac localization agrees with canonical projection-valued localization, while its position operator differs from the Newton--Wigner operator by an explicitly determined bounded self-adjoint correction. Full Dirac achronal localization is projection valued and represents achronal separateness by orthogonality, thus satisfying microscopic causality. After compression to the electron subspace, it becomes positive-operator valued while preserving causality. We further extend known results from spatial to general achronal regions, prove separation and norm-one criteria, and analyze the high-boost limit, obtaining Lorentz contraction in a precise probabilistic sense. Finally, we discuss the electron--positron decomposition and the state transformation induced by position measurements, showing that measurement-induced positron production is universal and independent of the specific measuring device.

math-ph↗

arXiv2026

Achronal localization and representation of the causal logic from a conserved current, application to the massive scalar boson

Only recently the concept of achronal localization has been developed as the adequate frame for the description of the localizability of a relativistic quantum mechanical system. Here covariant achronal localizations are gained out of covariant conserved currents computing their flux passing through achronal surfaces. This general method is applied to the probability density currents with causal kernel regarding the massive scalar boson. As (covariant) achronal localizations correspond one-to-one to (covariant) representations of the causal logic, thus, apparently for the first time, a covariant representation of the causal logic for an elementary relativistic quantum mechanical system has been achieved. Similarly a covariant family of representations of the causal logic is derived from the stress-energy tensor of the massive scalar boson. The construction of an achronal localization from a conserved current relies on a version of the divergence theorem for open sets with almost Lipschitz boundary. This result is stated and proved in this work.

math-ph↗

arXiv2024

Quantum particle localization observables on Cauchy surfaces of Minkowski spacetime and their causal properties

We introduce and study a general notion of spatial localization on spacelike smooth Cauchy surfaces of quantum systems in Minkowski spacetime. The notion is constructed in terms of a coherent family of normalized POVMs, one for each said Cauchy surface. We prove that a family of POVMs of this type automatically satisfies a causality condition which generalizes Castrigiano's one and implies it when restricting to flat spacelike Cauchy surfaces. As a consequence no conflict with Hegerfeldt's theorem arises. We furthermore prove that such families of POVMs do exist for massive Klein-Gordon particles, since some of them are extensions of already known spatial localization observables. These are constructed out of positive definite kernels or are defined in terms of the stress-energy tensor operator. Some further features of these structures are investigated, in particular, the relation with the triple of Newton-Wigner selfadjoint operators and a modified form of Heisenberg inequality in the rest $3$-spaces of Minkowski reference frames

math-ph↗