結論

Qiskitで作成した回路を別の回路に組み込みたいとき， qc.append( sub_qc, [q[m], q[m+1], ..., q[n]] )と書くことで追加できる．
[q[m], ... ,q[n]]はq[m:n+1]と書いても実行される．
sliceなのでn+1になる.

例

IBM Q Epxrerience上で実行した．

まずimport

%matplotlib inline
# Importing standard Qiskit libraries and configuring account
from qiskit import QuantumCircuit, execute, Aer, IBMQ
from qiskit.compiler import transpile, assemble
from qiskit.tools.jupyter import *
from qiskit.visualization import *
# Loading your IBM Q account(s)
provider = IBMQ.load_account()

from qiskit import *

sub_qcを定義，　あとでappendされる.

q = QuantumRegister(3)
c = ClassicalRegister(3)
qc = QuantumCircuit(q, c)
qc.draw()

sub_qcが完成

parent_qcを定義

q = QuantumRegister(4)
c = ClassicalRegister(1)
parent_qc = QuantumCircuit(q, c)
parent_qc.append( sub_qc, [q[1], q[2], q[3]] )
parent_qc.draw()

sliceの書き方version

q = QuantumRegister(4)
c = ClassicalRegister(1)
parent_qc = QuantumCircuit(q, c)
parent_qc.append( sub_qc, q[1:4] )
parent_qc.draw()

同じ結果が得られる．