i
i
i
i
i
a
4
a
3
a
2
a
1
a
0
b
0
b
1
b
2
b
3
b
4
U = e
−i
˜
H
˜
H =
P
l>j>k≥0
˜
H
j,k
˜
H
j,k
ρ
0
= π r = j − k
ρ
0
π r = j − k
U
QF T
−1
|ai
|bi
1/
√
L
a
0
j
= a
l−1−j
, j = 0, 1, . . . , l − 1
j k ≤ j
a
0
j
a
0
k
a
0
j
a
0
k
j > k a
0
j
b
k
j > k
b
j
b
k
j > k k j −k l −1 −j