Unanswered Questions
573 questions with no upvoted or accepted answers
8
votes
1
answer
410
views
Enforcing a particular layout mapping in Qiskit
I would like to ask how to set a particular layout during transpiling. I guess that the layout can be set by the initial_layout parameter in the transpiler. However,...
7
votes
0
answers
210
views
Run VQE for parametrized quantum circuit with ancilla qubits
Let's say we have the following circuit (picture and code shown below), and now the $q_0$ is an ancilla qubit. If the system of interest has only two qubits, Is there a way to use only $q_{1,2}$ as my ...
6
votes
0
answers
278
views
Quantum State Tomography Implementation in IBMQ
I am working to understand quantum state tomography, specifically using the algorithm presented in PRL 108, 070502. This paper is referenced in IBMQ implementations of QST, both in old deprecated ...
6
votes
0
answers
132
views
Writing circuits in Qiskit using only Clifford and T gates
Is there a way in Qiskit to write my circuit using only Clifford and T gates (CX, S, H, T and I think also $S^\dagger$ and $T^\dagger$)? With the function compile (with aer simulator) it gives me some ...
6
votes
0
answers
141
views
Bell State 11 not working for parity curve
I am currently writing a script to automate the creation of parity curves for a 2 qubit bell state and then calculate fidelity and proving entanglement from that (inspired by this paper). It was going ...
5
votes
0
answers
271
views
How to get the compiled circuits and measurements from a Qiskit Runtime job
I have not been able to find any way to retrieve the compiled circuits and the measurement counts used for a Qiskit Runtime job. This page describes the various error suppression mechanisms available. ...
5
votes
0
answers
662
views
Add noise_model when using 'ibmq_qasm_simulator' backend and provider.runtime.run() function
I am trying to test some qiskit code that employs readout-error mitigation using the ibmq_qasm_simulator backend and Qiskit Runtime. I am getting the backend as ...
5
votes
0
answers
132
views
Which improvements can we expect in Quantum Error Correction?
According to this article:
The surface code is currently the most widely pursued quantum error correction scheme
(Emphasis mine). It is also said:
However, there are drawbacks to the surface code, ...
5
votes
1
answer
718
views
Two qubit gate decomposition using Qiskit
I am writing some python code to be able to optimise the total error in two qubit gate decomposition.
I am using the Qiskit module qiskit.quantum_info.synthesis.two_qubit_decompose
My question relates ...
5
votes
0
answers
725
views
OpenFermion to Qiskit
Is there a direct way to go from an object generated in OpenFermion to objects usable in Qiskit? I can't find anything about any plugin.
It's not too hard to translate into pyQuil and then to Qiskit ...
5
votes
0
answers
160
views
Results from looped experiments on IBM Q different than individual experiments
I'm experiencing an issue while using Qiskit where the counts from a job return vastly different values when ran in a loop or as an array of circuits as opposed to single experiments when run by ...
5
votes
0
answers
157
views
How can I express controlled unitary operation in QPE of this implementation of HHL?
I have found this implementation of HHL, and I don't understand why the controlled unitary operation is expressed in the form of $\exp(i t_0 A/2)$ and $\exp(i t_0 A/4)$.
The rotation of $\pi$ and $\...
4
votes
0
answers
60
views
Evaluating expectation values of operators using StateVector and MPS in Qiskit 1.0
Assume one has a QuantumCircuit object and a list of SparsePauliOp. How do I calculate their expectation values using the MPS ...
4
votes
0
answers
94
views
Quantum Phase Estimation for Chemical Hamiltonian
I am working on implementing QPE for calculating the ground state energy of a small molecule like H2 or HeH+. I've written some code that is getting results within about 10% accuracy, but I'm not ...
4
votes
0
answers
68
views
Failed to load program into HAL component
I'm getting this error message when I execute my qiskit code on one of the available quantum computers of IBM:
...