New matrix-weighted norm inequalities and extrapolation

In this paper, we propose a new type of matrix-weighted theory and show the corresponding Rubio de Francia extrapolation theorems by means of noncommutative maximal inequalities. We introduce a new matrix $A_p$ condition following Volberg's geometric formulation, and characterize it via a noncommutative Hardy–Littlewood maximal inequality. We then establish a noncommutative analogue of Rubio de Francia's abstract extrapolation theorem for trace-finite von Neumann algebras. The argument extends to $L_\infty(\mathbb R)\bar\otimes M_d(\mathbb C)$ through pointwise matrix operations. This yields the desired extrapolation results for individual operators and maximal families, with applications to matrix-weighted boundedness of Calderón–Zygmund operators.