Floquet topological d+id superconductivity in the doped Hubbard model*

We study how d-wave superconductivity of the repulsive Hubbard model in the strong-coupling regime is changed when illuminated by circularly-polarised light (CPL), using the Floquet formalism for the Gutzwiller-projected effective Hamiltonian with the time-periodic Schrieffer-Wolff transformation. 

We find that CPL induces topological superconductivity with a d+id pairing, which arises from the chiral spin coupling and the three-site term generated by the CPL. 

These effects become significant for various frequencies red-detuned from the Hubbard U, which are verified by calculating the phase diagram and transient dynamics of the Floquet effective Hamiltonian.