Andris Ambainis Kazuo Iwama Masaki Nakanishi Harumichi Nishimura Rudy Raymond Seiichiro Tani Shigeru Yamashita Average/Worst-Case Gap of Quantum Query Complexities by On-Set Size http://arxiv.org/abs/0908.2468 2009 CoRR abs/0908.2468 db/journals/corr/corr0908.html#abs-0908-2468 informal publication