Monopoles and Wilson lines

We present a semi-classical description of BPS monopoles interacting with Wilson lines. The Wilson lines are represented as non-Abelian spin impurities. These spins interact with the monopole degrees of freedom through a natural connection on the moduli space. We employ this technology in 𝒩 = 2 SU(2) gauge theory to count the number of framed BPS states of a single monopole bound to Wilson lines in different representations.