We propose a protocol that enables a dealer to share a quantum secret with n players using less than n quantum shares for several access structures. For threshold schemes we derived an expression that shows how many quantum shares can be saved in this scheme. Also, several features that are available for classical secret-sharing schemes (and previously not known to be possible for quantum secret-sharing) become available with this protocol.
Physical Review A
Nascimento, Anderson C.; Mueller-Quade, Joern; and Imai, Hideki, "Improving Quantum Secret-Sharing Schemes" (2001). Institute of Technology Publications. 56.