Irregular Fibonacci Conformal Blocks

Abstract: This work studies Liouville conformal blocks of irregular type with the insertion of at least one level-$3$ degenerate field admitting a Fibonacci fusion rule. We algebraically derive the corresponding third-order BPZ equations for regular blocks and their modifications when a rank one irregular operator is inserted. Employing Lefschetz thimbles as integration cycles, we then successively proceed to construct integral representations and prove that they satisfy the corresponding BPZ equations. Finally, we show that taking a semiclassical limit, these integral representations can be expressed in terms of Heun functions and have correct leading behaviors consistent with conformal weights and fusion rules.