Quantum Brain
← Back to papers

Tagged vector space, Part I: Dirac notation as originally intended

Filippus S. Roux·October 20, 2025
Quantum Physicshep-thMathematical Physics

AI Breakdown

Get a structured breakdown of this paper — what it's about, the core idea, and key takeaways for the field.

Abstract

A generalization is provided for the notion of tags, as used in various formulations of physical scenarios. It leads to the definition of tagged vector spaces, based on a set of axioms for tags and their extractors. As an application, such a tagged vector space is used to provide, in the context of quantum optics, a formal mathematical description for the Dirac notation that is closer to its intended usage compared to current mathematical formulations: it provides a one-to-one mapping between kets and bras and allows operators to operate either to the left or to the right. The canonical commutation relations for the quadrature and ladder operators are derived as consequences of the axioms of the tagged vector space. These axioms also lead to a symplectic phase space with the Wigner function and the Weyl transform emerging naturally.

Related Research

Quantum Intelligence

Ask about quantum research, companies, or market developments.