# 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.

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### Strange output using Qiskit QFT example

I am trying to follow the examples of the QFT from the qiskit textbook (https://qiskit.org/textbook/ch-algorithms/quantum-fourier-transform.html), and I cannot figure out why I am getting 'Job ...
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### Oracle with multiple solutions, Grover's Algorithm- Qiskit

Using qiskit, I want to build an oracle with multiple solutions. I am planning to use 10qubits. I don't know if i'm doing it right but where it goes: ...
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### Difference between Aer.get_backend('aer_simulator') and AerSimulator()

In Qiskit, there are several ways to choose simulator: one is from qiskit import Aer backend = Aer.get_backend('aer_simulator') result = backend.run(circ).result() ...
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### Measuring in qiskit collapses onto the Z-Plane. Why do any rotations other than Y matter?

We have the situation where a 50/50 split between $|1\rangle$ and $|0\rangle$. This was done using a $H$-Gate. Now, when measuring in qiskit, if my understanding is ...
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### How to perform multi-class classification with qiskit's VQC?

I am following the tutorial given in qiskit's website Neural Network Classifier and Regressor. In the first part, classification, the third section refers to qiskit's VQC library. Everything works ...
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### Why isn't $Ry(\pi/2)$ gate equivalent to Hadamard gate?

I've been experimenting with quantum circuits and can't quite fathom how the difference between states comes together. Speaking in terms of simulations using qiskit,...
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### How to set hyper parameters for a Variational Quantum Classifier (qiskit)?

I am trying to implement a Variational Quantum Classifier using qiskit's VQC. I have set the feature map to ZZFeatureMap and am using the ...
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### Qiskit's classifier is not optimising the weights

I am using qiskit's VQC to build a classifier. Dimensionality of the data is 2 and number of classes are 4. The feature map I used is ZZFeatureMap and ansatz is the RealAplitudes. Then entanglement ...
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### Qiskit's draw only shows the circuit's name and not the architecture [migrated]

Upon trying to draw a ZZFeatureMap instance, I only see the name "ZZFeatureMap" and not it's architecture. Please find the code snippet and output ...
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### Two body integral calculation taking too long

I'm running the most recent version of qiskit and am trying to run H2 in the cc-pvtz basis. However, it is taking an incredibly long time. This is what my code looks like: ...
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### How is transformation for measurement in an arbitrary basis derived?

I started with Qiskit today and find it very exciting. As a first question I want to understand how to measure an arbitrary state $|\Psi\rangle$ not in the basis of ...
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### How to write a code to made envelope function equal to $\pi$ to result in an X gate?

$$\hat U_d = \exp\Big( -i\underbrace{\frac{Q}{2}\int_0^T A(t^\prime)\mathop{dt^\prime}}_{\Theta(t)} \hat\sigma_x \Big)$$ This equation is a Unitary transformation applied to a qubit from time $t = 0$...
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### How do you access stored Ramsey experiment frequency?

What is the stored frequency for the Ramsey experiment and how can this stored frequency be accessed? Is there a backend.get(frequency) command for this frequency?
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### Working with higher energy states in Qiskit Experiments

I'm looking at the source code for the Qiskit Experiments module and see that the EFRabi class subclasses the Rabi class with the intent of calibrating rotations between the 1 and 2 states instead of ...
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### What is the computational complexity in initializing a quantum register?

I'm trying to figure out what is the computational complexity of initializing a quantum register of N qubits. For my research, I have used the initialize method of qiskit, in which you set the ...
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### Confusion about Mitiq folding for zero noise extrapolation

I'm reading the mitiq zero noise extrapolation documentation and I just can't make sense of how the scale_factor for folding work. "The minimum scale factor is one (which corresponds to folding ...
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### have to process 512×512 pixel image will it be possible in Qiskit. what hardware requirement will be?

I'm working on Quantum image processing of satellite images. I'm completely a beginner also I'm learning it by my own that's why I need help. Can you please help me out I want to process the image of ...
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### from hello_qiskit import run_puzzle results in error

I am working my way through the beta version of the Qiskit textbook. Everything was going fine until I got to the Visualizing Entanglement section and had some exercises to complete. All of the ...
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### How can I create a Qiskit function producing a quantum circuit such that $\langle Z^{\otimes n}\rangle=J_{n-1}/2^{n-1}$?

Problem: Create a function circ(n) that returns an $n$-qubits quantum circuit that, when measured in the $Z^{\otimes n}$ basis, should yield the following ...
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### Where does the "correction" in quantum error correction occur, specifically when using repetition codes?

I'm reading the part of the qiskit textbook that deals with this (https://qiskit.org/textbook/ch-quantum-hardware/error-correction-repetition-code.html) and so far it seems as though they're just ...
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### Getting non-Clifford after performing several Clifford gates in qiskit

I'm trying to test Clifford gates in qiskit according to the table in Fault-tolerant SQ, page 101. I tried 4 Cliffords in the test $$-X/2 - X -X/2,Y/2,X/2 - -X/2,Y/2,-X/2$$ using the following code <...
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### Amplitude encoding: distinction between negative and positive real values

I want to encode two vectors into qubits and compute a distance between them that corresponds/is proportional to the euclidian distance of the real vectors. The encoding I use is A) qiskit ...
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### Why in quatum coin toss, when starting from state $|1\rangle$, we get $|-\rangle$?

I was reading qiskit's text book, there I found that for a Double quantum coin toss, we have negative probability amplitude for $|1\rangle$ state when we starts from $|1\rangle$ state. Link : https://...
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### Is it possible to use the mitigation process on a teleportation circuit?

Is it possible to use the mitigation process on a teleportation circuit? Sorry, i'm still starting, if someone can get me out of this doubt, I would appreciate it. The circuit I'm trying to make this ...
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### How to apply gates based on a random decision on the IBM quantum computer?

I want to run a circuit on an IBM quantum computer, and this circuit involves gates that are either applied or not based on a (classical) random decision. As a minimal example, imagine a circuit with ...
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### How to run Qiskit's transpile in parallel in Windows?

I want to execute qiskit transpile function in parallel. My experiment environment OS is Windows, and the Qiskit version is 0.29.1. I already asked one question here, and I also changed the file ...
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### Expected outcome of adding two PauliOp

first of all, I would probably report this as a bug if I was confident enough in my QC abilities. As it stands, I've just started out, so I'm phrasing it as a question. From what I can tell, adding ...
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### Exacting specific results in running a list of tomography circuit

I run a test on tomography of two circuits like this: ...