Questions tagged [initialization]
For questions regarding the initial state of a system for quantum computation and their preparation.
16
questions
0
votes
1answer
42 views
How to separate initializing qubits from runing algorithm several times
I have read several papers about quantum computing. It looks like any algorithm consists of several phases. For example in Grover algorithm initially qubits must be initialized from reset state $|0\...
4
votes
1answer
63 views
How is the state preparation Unitary in initialize selected?
Normally, in order to prepare the Bell state $\frac{1}{\sqrt{2}}(|00\rangle+|11\rangle)$, we can simply make a circuit with a Hadamard gate on $|0\rangle$ followed by a CNOT gate on $|1\rangle$. ...
1
vote
1answer
68 views
Setting the Initial State of Density Matrix Simulation in Cirq
I am trying to use the DensityMatrixSimulator in Cirq. I want to append gates to the circuit conditional on measurements. In order to reduce computational resources, I am trying to run these ...
2
votes
0answers
60 views
Why wont my custom controlled gates in Cirq work on a simulator?
To initialize a state in Cirq, I created a custom controlled rotation and a custom rotation gate. The effect of applying the custom controlled gates to the qubits doesn't seem to affect the state.
...
2
votes
1answer
75 views
Using QuantumCircuit.initialize() on a real quantum computer
Can the qiskit function QuantumCircuit.initialize be used to initiate any number of qubits (which exist currently on the quantum computers) and can it be used on a real quantum computer?
1
vote
5answers
680 views
Qiskit: Initializing $n$ qubits with binary values ($0$s and $1$s)
Is there a way in Qiskit to initialize $n$ qubits with binary values (0s and 1s)? For example, how can I initialize two qubits in the state $|11\rangle$? Here is a code snippet:
...
3
votes
1answer
464 views
Why after transpiling a Qiskit circuit we obtain a different result?
I am trying to obtain the correct circuit transpiled for the ibmq_london device, as I want to know what the real gates applied in the quantum computer are. I am implementing the QFT circuit for 5 ...
3
votes
2answers
76 views
Is there a "parameterized initialization" that I can apply to a QuantumRegister to re-use a circuit?
I'm working on a QuantumCircuit which measures the fidelity of one point (my "test vector") and two other points (my "data set", containing of states phi_1 and <...
1
vote
1answer
181 views
How can I initialize a state with chosen amplitudes in Qiskit?
I was trying to initialize to an arbitrary state of n qubits with the initialize() from Qiskit but it doesn't generate a state with the same amplitudes passed as an ...
2
votes
1answer
170 views
VQE restart from a previous computation
I'm running VQE algorithm on ibmq-qasm-simulator.
I'm trying to implement a restart mechanism in order to be able to start a new computation from the result of a ...
1
vote
1answer
377 views
Prepending initial state to a quantum circuit in Qiskit
I am trying to generate a Quantum Phase Estimation (QPE) circuit in QISKIT the following way.
1 - First, I generate a QPE circuit with the following code:
...
3
votes
1answer
59 views
How to pick number of simulation qubits for finding eigenvalue of fermionic Hamiltonian?
I am having some trouble understanding how the number of simulation qubits are chosen when finding the eigenvalue of a fermionic Hamiltonian.
For the phase-estimation algorithm, is the number of ...
1
vote
1answer
59 views
Default value for a state created by QuantumRegister
What's the default value for a state created by QuantumRegister(1,'name_of_the_register')? Is it a $|0\rangle$ or a $|1\rangle$?
-1
votes
1answer
88 views
Default input states of qubits to quantum circuits [closed]
It is conventional to assume that the state input to the circuit is a
computational basis state, usually the state consisting of all
$|0\rangle$s. This rule is broken frequently in the literature ...
6
votes
0answers
120 views
Projective measurements: aftermath and restoration
I have some practical difficulties with projective measurements, so I'd welcome inspiration from others. This is beyond the question "Are true Projective Measurements possible experimentally?" in that ...
6
votes
1answer
125 views
Threshold and practical requirements for initial state preparation?
At the beginning of a quantum computational process we generally want to start in a perfectly known initial state, and evolve from there. This cannot be done perfectly, for fundamental reasons, but I ...