Is there there any way to create a known quantum state in Qiskit (or any other platform) comprising of two or more than two bit?
For example if I want to create $\frac{1}{\sqrt{3}}[|00\rangle+|01\rangle+|11\rangle]$. What I want to do is to know the unitary transformation ( or the quantum circuit) to prepare this (or any valid) quantum state for me.
As Martin Vesely mentioned in the comments, you can use the initialize function to perform such a task. For instance, to create the state you desire, you can do the following:
import numpy as np
from qiskit import QuantumCircuit
from qiskit.transpiler.passes import Decompose
qc = QuantumCircuit(2)
initial_state = np.array([1, 1, 0, 1], dtype=float)
initial_state /= np.linalg.norm(initial_state)
qc.initialize(initial_state)
qc.decompose().decompose().decompose().decompose().draw("mpl")
which draws the following output:
To know how does qiskit create this unitary, have a look at this answer.
