Free field realization of the quantum toroidal algebra of $\mathfrak{gl}_1$ with general levels

Abstract: We present a unified free field realization of representations for the quantum toroidal algebra of $\mathfrak{gl}_1$ with arbitrary levels, constructed using six free boson fields. This realization arises from a specialized factorization of the structure function within the defining relations of the quantum toroidal algebra of $\mathfrak{gl}_1$. Utilizing this free field realization, we further develop intertwining operators for the algebra of $\mathfrak{gl}_1$.