Questions tagged [qiskit]
Qiskit is an open source SDK for working with quantum computers at the level of pulses, circuits and application modules. If appropriate, also use the [programming] tag. Please include the version of Qiskit you use when using this tag.
2,099
questions
1
vote
0
answers
16
views
How does Qiskit's oracle synthesizer work?
Qiskit provides a phase oracle method that takes a Boolean formula as input and returns a phase oracle circuit for that function as output.
Their source code informed me that the synthesis uses the ...
- 195
0
votes
0
answers
21
views
Why EfficientSU2 in QGAN
In Qiskit's QGAN example, the parameterised quantum circuit to be trained is the EfficientSU2. I have not found any citation there on the choice of this circuit, and the only justification is that it ...
0
votes
1
answer
50
views
How to simulate a $CNOT$ only using a single qubit?
I am looking to do a $CNOT$ on itself, i.e., if the qubit is in $|0\rangle$ it stays in $|0\rangle$ and if it is in $|1\rangle$ it becomes $|0\rangle$. We are allowed to use $H$, $X$, $Z$, and $CNOT$ ...
1
vote
0
answers
23
views
MissingOptionalLibraryError: "The 'pdflatex' library is required to use 'LaTeX circuit drawing' [closed]
Trying to run the below code block in a jupyter notebook in Windows 10:
...
- 11
0
votes
0
answers
29
views
Qiskit Aer.backends() resulting in memory error
When I run the following python code
from qiskit import Aer
Aer.backends()
I get this error instead of a list of backends:
...
- 1
2
votes
1
answer
55
views
Calculating the Expectation Value After Mid-Circuit Measurements in Qiskit
I've been trying to implement a QML algorithm but I've run into a problem with calculating the expectation value of a certain part of the circuit after doing mid circuit measurements. I have a ...
0
votes
0
answers
43
views
How can I simulate EPR and Bell’s inequalities in qiskit?
According to Bernard Zygelman "A First Introduction to Quantum Computing and Information", I can compute the $QS|f\rangle$ with $|f\rangle = \frac{1}{\sqrt{2}} (|00\rangle -|11\rangle)$, ...
0
votes
1
answer
21
views
How can one obtain all calibration data which is needed to plot error_map of the ibm backend from few month ago?
I want to plot the error map of an IBM Quantum backend from the calibration data I saved a month ago. The saved file just contain qubit properties and to plot error map I would need all information ...
- 27
1
vote
1
answer
36
views
Statevector from Density matrix of non-pure state
I have a state vector of a 16 qubit system. I want to get the wave function (in the form of a state vector) for half and quarter of this system. When I try to make a ...
0
votes
1
answer
21
views
Step Optimize1qGatesDecomposition in qiskit transpilation
Is there a way to know what does it does qiskit in the step Optimize1qGatesDecomposition?
What I can see is that each time qiskit wants to represent a rotation in ...
- 519
0
votes
2
answers
49
views
How can visualise the old error map of Ibm backend if one save the calibration data of the backend at that time?
I have the calibration data of an Ibm backend and now I want to plot the error map of the device at that specific time.
How can I do this?
- 27
1
vote
1
answer
48
views
How to implement non-unitary operator in qiskit?
I am trying to make a operator for S-Box for AES. The matrix is non-unitary. When I use Operator command for declaring it as a function. It gives error, the matrix is non-unitary. Thus, the qiskit ...
3
votes
1
answer
63
views
Is it possible to get step-by-step information about qiskit transpilation?
Is it possible to get the information about the step by step transpilation? I have circuits that I know how it is more or less structured after the transpilation, but when I join them to create a ...
- 519
0
votes
0
answers
22
views
Retrive IQ Data from Fake Backend in Qiskit
Is it possible to retrieve IQ data from Fake Backends in Qiskit?
I'm trying with the following code, but even by setting meas_level=1, I get only count vectors.
<...
1
vote
0
answers
52
views
Is it possible to convert a qudit to a qubit?
I am trying to write a Qiskit code for a algorithm which uses qudits. I want to use qubits instead because $p$ value can go pretty high. Is it mathematically possible to convert qudit to qubit for ...
0
votes
1
answer
32
views
Given a COMPLEX unitary matrix, how can I construct a unitary gate in Qiskit?
It seems that it is fairly easy to construct a unitary gate given a real unitary matrix. However, I have tried several methods with a complex unitary matrix, but they all seem to be not working. How ...
- 3
0
votes
0
answers
17
views
Optimizing Selection of the Optimal Qubit in a 30-Qubit Quantum Circuit
I am working with a quantum circuit consisting of 30 qubits, and for each qubit, I have allocated a dedicated classical register to record individual measurement results. When I execute this circuit ...
2
votes
1
answer
42
views
Half Adder using CNOT Gates
As per this schematic of qubits, how this explanation is correct --"If you look again at the four possible sums, you’ll notice that there is only one case for which this is 1 instead of 0: 1+1=10....
0
votes
0
answers
25
views
Running multiple amplitude estimations simulations
I am working on a mini project investigating the scalability of quantum computing in the context of option pricing.
I have been following the above Finance API from Qiskit as an introduction, however, ...
0
votes
0
answers
35
views
Converting Ising Hamiltonian to a Circuit in Qiskit
I tried to solve a 2-node TSP (travelling salesman problem) by implementing QAOA on Qiskit. The graph looks like:
Then I used the related Qiskit functions to convert the graph to the QUBO and map it ...
- 159
1
vote
0
answers
32
views
Building a problem unitary circuit for QAOA on Qiskit
I am trying to build a circuit for QAOA that solves a Traveling Salesman's Problem, which can be represented as a complete graph with 4 nodes. After formulating the problem as a QUBO and mapping it ...
- 159
0
votes
1
answer
70
views
Design a full adder to add two 4-bits integer and measuring on 4 quantum states
I am trying to implement a full adder with minimum of 8 qubits to add two 4 bit integers. Integer 1 will be added on q[0-3] while integer 2 will be added on q[4-7]. The output will be measured on q[0-...
- 1
1
vote
0
answers
71
views
Representing networks with qubits as edges
I am looking to take a classical non-negative real valued network and generalize it to the quantum case for processing. A network is given by an adjacency matrix, essentially edge weights $e_{ij}$ for ...
- 153
1
vote
2
answers
108
views
How to design a circuit which produces the state $|\psi\rangle = \frac{1}{2}|{010}\rangle + \frac{\sqrt{3}}{2} |{101}\rangle$?
The quantum state to achieve is:
$$
|{\psi}\rangle= \frac{1}{2}|{010}\rangle + \frac{\sqrt{3}}{2}
|{101}\rangle
$$
So far I know how to produce the $$\frac{1}{2}|{010}\rangle$$ state in qiskit as ...
- 11
0
votes
0
answers
21
views
Can't run QubitSpectroscopy from qiskit experiments library
So this question inherits from my previous problem , but owing to its perceptible distinction, I decided to write it separately. Long story short, I want to construct a Qubit Spectroscopy experiment ...
- 17
1
vote
1
answer
44
views
Limited qubit number available in Aer Statevector simulator
I tried to run a calculation of 37 qubits with a Statevector simulator on Qiskit. The following is a demo code.
...
- 107
0
votes
2
answers
47
views
Trying to run qubit spectroscopy on FakeManila backend, got unknown instruction error
Right now I'm trying to delve into qiskit pulses and its usage with quantum hardware. First of all I decided to run spectroscopy experiment with FakeManila backend:
...
- 17
0
votes
0
answers
14
views
How do I implement implicit identity error in Qiskit?
I recently noticed a difficulty I'm having with Qiskit Aer. I want to simulate a quantum circuit where idling qubits suffer some noise. The problem is that AerSimulator doesn't implement noise on ...
- 149
0
votes
0
answers
21
views
Functional form of the drive of IBMQ machines
I am trying to apply some ML techniques to try and find out pulse sequences to implement different kinds of gates using Qiskit Pulse. For the ML part, it is necessary for me to know the Hamiltonian of ...
- 1
1
vote
1
answer
42
views
Implementing swap test on quantum register
I'm interested in implementing a controlled-swap operation on quantum registers. However, it appears that Qiskit's documentation primarily focuses on single qubits rather than registers. Could you ...
- 21
0
votes
1
answer
33
views
qiskit with our own backend
In our laboratory we have our own cryostat and quantum chips, so I wondered if is it even possible to mate our own hardware (HDAWG, etc.) with qiskit framework? It would be great to build pulse ...
- 17
1
vote
1
answer
23
views
Obtaining the unitary matrix of a gate in analytic form in qiskit
Is there any way to obtain the unitary matrix of single way in analytic form?
In numerical form, I could use a workaround like this (i.e. for an X Gate):
...
- 121
0
votes
0
answers
20
views
How to account for a partial derivative term in an Operator, in Qiskit?
The crystal momentum p1 = h bar * k and this is defined in the reciprocal momentum, I am guessing this p1 is not a real momentum since the reciprocal space is an imaginary space which we use for ...
1
vote
1
answer
35
views
Is it possible to train a QNN in parallel so that all qubits in the quantum computer can be utlised?
I wish to use quantum machine learning to help forecast temperature by using a dataset with 5 different features. I had currently achieved this using Qiskit with 5 qubits, with ZZfeaturemap and ...
- 13
1
vote
0
answers
47
views
bad solution to the knapsack problem on Qiskit
To solve the knapsack problem, I translate it into a QUBO. But the solutions obtained on the simulator are incorrect. Are there ways to make the answers correct?
The picture shows the cost function, ...
1
vote
0
answers
349
views
Error "_legacy_format_cache" at QISKIT lab during gthe submission of answer to grader for summer school 2023
I was working on the qiskit summer school 2023 lab. While I was submitting the answer to grader, suddenly I got a response mentioning _legacy_format_cache error. I ...
- 29
3
votes
0
answers
27
views
Difference between Qiskit and Openfermion two body integrals
I am struggling with understanding the differences between OpenFermion and Qiskit libraries when it comes to Molecular Data, two body integrals.
For example, I am working with the following ...
- 31
1
vote
0
answers
10
views
How to get rid of the indices of qubits at the side of a custom gate when visualizing a circuit (IBM Qiskit)
I have written a function that applies the Hadamard gate to all qubits in a circuit, and use the draw() function to visualize the circuit. However, there is this ...
- 11
2
votes
2
answers
36
views
Visual the qubit state after amplitude encoding
I trying to visualize qubits state after amplitude encoding.
I have the following code which takes the 8 feature [1/2, 1/2, 1/2, 1/2,1/2, 1/2,1/2,1/2] and encodes into 3 qubits.
I now get the output [...
1
vote
2
answers
74
views
Can any Qiskit circuit be converted to a gate?
I am trying to convert the following qiskit QuantumCircuit to a gate using to_gate() method.
...
2
votes
0
answers
30
views
Minimum working example for Qiskit's AdaptVQE
I am trying to implement a simple AdaptVQE in Qiskit. Following the documentation provided by Qiskit, this should be very simple:
...
- 149
1
vote
1
answer
33
views
IBMQ Open Plan Access: How many circuits can i run per job? How many jobs can i run in general?
I think my question is not difficult at all, but I don't find any Information about the Open Plan of IBMQ. Such as how many circuits I can run per job and so on.
I could not find the EULA too, I ...
- 151
0
votes
1
answer
51
views
Plotting the Bell state on a Bloch sphere
How can you plot the bell state on a Bloch sphere?
bell = QuantumCircuit(2)
bell.h(0)
bell.x(1)
bell.cx(0,1)
Is there any good reference for understanding how ...
- 145
0
votes
0
answers
33
views
How to predict state vector of a quantum circuit in IBM qiskit
How to Predict the state vector output of the following quantum circuit?
...
- 145
1
vote
1
answer
80
views
0
votes
1
answer
43
views
0
votes
0
answers
14
views
Qiskit Aer Noise Module
I am trying to use the following single qubit depolarizing channel (on a GHZ state for example) but the simulation histogram counts are not affected
...
- 41
1
vote
1
answer
27
views
Are equiprobable state same as superposition state
How
qc.h(0)
qc.h(1)
helps quantum circuit
qc=QuantumCircuit(2)
to put the given qubits in a equiprobable states?
Are ...
- 145
0
votes
2
answers
42
views
Visualizing Y-gate operation to achieve quantum state
In the below snippet how qc.y(1) helps to achieve the quantum state $i|10\rangle$ ?
...
- 145
2
votes
1
answer
47
views
How do I interpret the results of a grover's algorithm graph?
I have recently been using Grover's algorithm to solve sudoku by coding. I am unsure how to interpret the graph produced. Could anyone explain?
I have included a link where you can view the graph: ...
- 21