Tighter superadditivity relations for l1-norm coherence measure

Quantum coherence serves as a crucial physical resource, with its quantification emerging as a focal point in contemporary research. Superadditivity constitutes one of the most fundamental attributes in characterizing the coherence distribution in multipartite quantum systems. In this paper, we provide a way to derive tighter superadditivity inequalities of l₁-norm coherence measure for arbitrary multiqubit states. We present a category of superadditivity relations related to the α-th (α 2) power of l₁-norm coherence C_l₁ under certain conditions. Our results are better than existing ones and are illustrated in detail with examples.