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
0
votes
1
answer
78
views
SX operator and superposition
I am running some tests using the probabilities we get from statevector to assert values in qiskit. For instance, with two qubits and a hadamard gate on the first one we have:
...
CommunityBot
- 1
1
vote
2
answers
129
views
Symmetric Universal Quantum Cloning Machine (UQCM) N --> M for unknown states
Does it exist a schematic diagram of the quantum circuit implementing the symmetric UQCM N--> M for unknown states? If yes, does anyone know a Qiskit implementation of it?
CommunityBot
- 1
0
votes
0
answers
13
views
Background job in Qiskit not showing output on .ipynb file?
I've successfully run jobs to measure circuits on Qiskit (Shor's algorithm for $N=15$ or simpler). However, it appears when I close out of everything and leave, the output of the job doesn't show in ...
- 205
1
vote
1
answer
89
views
Calculating state fidelity and space complexity of Minimum Eigen Optimizers (VQE, QAOA and Grover Optimizer) in qiskit
I'm a beginner in using Qiskit and my Computer Science background is not extensive. But I understand the Quantum Physics aspects of it relatively well.
I solved a QUBO problem in Qiskit using VQE (...
CommunityBot
- 1
3
votes
0
answers
42
views
4 qubit QFT decomposition in the qiskit textbook
I am reading about the quantum Fourier transform (QFT) in the qiskit textbook, but got stuck at the last part of it which shows a decomposed version of the 4 qubit QFT circuit.
It seems that the ...
- 5,112
0
votes
1
answer
87
views
CCX (Toffoli) gate calculation
I expected |110> since we do
a -> a
b -> b
c -> ab + c (mod 2)
since x 0 -> 1 and 1+1 = 0 mod 2
we get 110. Why is qiskit returning 011?
CommunityBot
- 1
1
vote
0
answers
28
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
1
vote
0
answers
30
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 ...
- 608
1
vote
2
answers
409
views
Binary classification using a very simple Neural Net with Qiskit and Pennylane
I implemented a simple Neural Net with Pennylane and Qiskit for classifying two half moons: notebook for two half moons (GitHub). It works somehow (not overwhelmingly by any means):
I tried running ...
CommunityBot
- 1
0
votes
1
answer
53
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 $CNOT$ ...
- 41
2
votes
1
answer
69
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 ...
- 608
-1
votes
0
answers
35
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
1
vote
0
answers
26
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
1
vote
1
answer
56
views
Qiskit library.gaussian() does not accept parametric expression
I'm trying to build a gaussian pulse in qiskit where I keep the amplitude as a parameter but for the followig code
...
CommunityBot
- 1
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 $i|10\rangle$ ?
...
- 571
2
votes
1
answer
258
views
Qiskit does not interpret qasm string as 3.0?
I am trying to get my first openqasm3.0 program and I am getting error messages that I cannot interpret.
Here is my program:
...
CommunityBot
- 1
0
votes
0
answers
45
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 $|f\rangle = \frac{1}{\sqrt{2}} (|00\rangle -|11\rangle)$, ...
- 608
1
vote
1
answer
202
views
Unable to perform actions on initialized states in qiskit
I have the code below which initalized a state in a quantum circuit then tries to perform some simulation. This doesn't work if I keep the initialize line uncommented, but runs just fine if I comment ...
CommunityBot
- 1
1
vote
0
answers
72
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 ...
- 205
0
votes
1
answer
137
views
Encoding classical data to quantum space
I went through the link " https://learn.qiskit.org/course/ch-applications/hybrid-quantum-classical-neural-networks-with-pytorch-and-qiskit" where a hybrid of classical and quantum ...
CommunityBot
- 1
0
votes
1
answer
107
views
Parameterized circuits and Z expectation values - Qiskit
I have a simple parameterized quantum circuit which looks like the image attached. Here is the code used to create it:
...
CommunityBot
- 1
0
votes
1
answer
48
views
1
vote
1
answer
37
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
22
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 ...
- 8,454
2
votes
2
answers
37
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 [...
CommunityBot
- 1
0
votes
2
answers
50
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?
- 8,454
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 ...
- 8,454
2
votes
1
answer
63
views
How to represent two gates addition on Qiskit composer. we can do tensor product and multiplication but how to do Addition
How to represent two gates addition on Qiskit composer we can do it in python code by using qiskit library but I would like to visually see how addition of two operators look like in composer.
I am ...
CommunityBot
- 1
1
vote
1
answer
50
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 ...
- 5,112
0
votes
0
answers
23
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.
<...
- 20k
3
votes
1
answer
64
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 ...
glS♦
- 22.9k
0
votes
1
answer
56
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 ...
- 608
0
votes
1
answer
111
views
How to get information about 'qubit location' or 'variable of qubit location' in qiskit docs?
I have something problem with using qiskit.
I searched several qiskit docs to get 'qubit location' or 'variables' that represent qubit.
I searched three documents below.
...
CommunityBot
- 1
1
vote
0
answers
53
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 ...
- 13.5k
3
votes
1
answer
104
views
Can the ancilla for Qiskit's mcx with mode="recursion" be dirty?
I think their implementation is close to the one from here which does use a dirty ancilla, but I just want to make sure
CommunityBot
- 1
3
votes
1
answer
188
views
What are the possible gates that I can use to vary input states before CNOT?
We know that the noise of the $\text{CNOT}$ gate varies depending on the input state before it.
What are the gates that I can put in the place of the 4 identity gates above to change the input state ...
CommunityBot
- 1
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 ...
- 608
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....
- 8,454
0
votes
1
answer
122
views
Trouble re-creating quantum psuedo-telepathy
I am trying to replicate the results from this webpage here utilizing qiskit:
http://twistedoakstudios.com/blog/Post6536_implementing-quantum-pseudo-telepathy
Since the splitter gate mentioned in the ...
CommunityBot
- 1
4
votes
2
answers
1k
views
In Grover, how to implement oracle and amplification using Qiskit?
I found some examples of implementing the oracle when the marked state is $|000\rangle$.
But how can we know what gate we should use inside of the oracle?
Besides, for the part implementation, the ...
CommunityBot
- 1
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 ...
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, ...
2
votes
1
answer
359
views
QUBO defined in Qiskit/DOcplex: how to solve it using Pennylane?
I have a complex Integer Linear Programming model defined in DOcplex/Qiskit representing a combinatorial optimization problem.
Using the Qiskit utils, it is possible to covert it to either an Ising ...
CommunityBot
- 1
0
votes
0
answers
38
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 ...
- 608
0
votes
2
answers
119
views
How to perform the measurements on a quantum circuit in W state basis?
I need to perform the measurements on a quantum circuit in the basis $\{ \eta^\pm,\zeta^\pm \} $. Where $ \eta^\pm,\zeta^\pm $ are given as follows:
$$\eta^\pm = \frac{1}{2}|001\rangle + \frac{1}{2}|...
CommunityBot
- 1
0
votes
1
answer
165
views
How to get the matrix of a quantum circuit when the ancilla qubit is set to a specific state?
I would like to get the matrix form of a quantum circuit, representing the operation on normal qubits, after specifying the ancilla qubit at a given state. Is there any way to realize this using ...
CommunityBot
- 1
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
108
views
ImportError qiskit_ibm_runtime
When I try to import qiskit_ibm_runtime I get the following error:
...
CommunityBot
- 1
1
vote
1
answer
49
views
Qiskit's measurement error mitigation from counts data only, in 2023
Months or years ago, in a remote part of the globe, someone accessed an IBM Quantum computer online to perform a real experiment. She saved the resulting measurement outcomes of the algorithm in csv ...
CommunityBot
- 1
2
votes
1
answer
88
views
Qiskit IBMQ.load_account fails on version 0.20.0
So when trying to load my account I get this error:
...
CommunityBot
- 1