Concepts of a quantum information theory of many letters

TL;DR

This paper introduces a theoretical framework for quantum information theory that handles variable-length quantum messages by constructing a many-letter space analogous to Fock space, enabling measurement of message length.

Contribution

It generalizes standard quantum information theory to include variable-length messages through a novel many-letter space construction.

Findings

Defines a length operator for quantum messages.

Generalizes block message Hilbert spaces to variable lengths.

Provides a foundation for quantum message length measurement.

Abstract

A theoretical framework is presented allowing the treatment of quantum messages with components of variable length. To this aim a many-letter space, similiar to the Fock space, is constructed, generalizing the standard quantum information theory of block messages of fixed length. In the many-letter space a length operator can be defined measuring the length of a quantum message, whose eigenspaces are the block Hilbert spaces used in the standard theory.