Field-induced Kitaev multipolar liquid in $d^{2}$ honeycomb Mott insulators

The Kitaev model, characterized by bond-dependent Ising spin interactions among spin-orbit entangled dipole moments in Mott insulators, offered a new approach to quantum spin liquids. Motivated by another type of bond-dependent interaction among quadrupole moments in 5$d^{2}$ Mott insulators, we provide a microscopic route to uncover the Kitaev multipolar liquid, featuring fractionalized excitations out of non-Kramers doublets carrying multipole moments. The key ingredient is the magnetic field that allows for quadrupole-octupole interactions via mixing with the excited triplet states. The conditions to realize this phase in real materials is also discussed.