Title: Floquet multi-Weyl points in crossing-nodal-line semimetals,
Abstract: Weyl points with monopole charge $\pm 1$ have been extensively studied,
however, real materials of multi-Weyl points, whose monopole charges are higher
than $1$, have yet to be found. In this Rapid Communication, we show that
nodal-line semimetals with nontrivial line connectivity provide natural
platforms for realizing Floquet multi-Weyl points. In particular, we show that
driving crossing nodal lines by circularly polarized light generates
double-Weyl points. Furthermore, we show that monopole combination and
annihilation can be observed in crossing-nodal-line semimetals and nodal-chain
semimetals. These proposals can be experimentally verified in pump-probe
angle-resolved photoemission spectroscopy.