Stronger superadditivity relations for multiqubit systems

TL;DR

This paper develops tighter superadditivity inequalities for the $l_1$-norm of coherence in multiqubit systems, providing a more precise understanding of coherence distribution among subsystems.

Contribution

It introduces new superadditivity relations based on the $eta$-th power of $l_1$-norm coherence, generalizing and refining existing inequalities for multiqubit states.

Findings

Derived tighter superadditivity inequalities for multiqubit coherence.

Included existing results as special cases of the new inequalities.

Provided a detailed example illustrating the improved characterization.

Abstract

Superadditivity relations characterize the distributions of coherence in multipartite quantum systems. In this work, we investigate the superadditivity relations related to the $l_1$-norm of coherence $C_{l_1}$ in multiqubit quantum systems. Tighter superadditivity inequalities based on the $\alpha$-th ($\alpha\geqslant 1$) power of $l_1$-norm of coherence are presented for multiqubit states under certain conditions, which include the existing results as special cases. These superadditivity relations give rise to finer characterization of the coherence distributions among the subsystems of a multipartite system. A detailed example is presented.