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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What does it mean for a Qiskit pulse to have a negative amplitude?

I'm going through tutorials on Qiskit Pulse. From this documentation, I can see that it is possible to give a pulse, such as a Gaussian a few different parameters. One of the parameters that I can ...
3 votes
1 answer
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Reasonable Circuit Depth

So I'm auto-constructing quantum circuits that are being auto-generated from dimacs files along with the addition of the amplification function. It's for a satisfiability problem where the number of ...
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ModuleNotFoundError when running Qiskit RNG

I'm trying to generate random numbers using IBMQ backends with the following code: ...
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State tomography with Pauli basis measurements for a high number of qubits

My end goal is to recover the quantum state in its computational basis or reduced density matrix of a high number qubit circuit in a real QPU. Taking into account that the number of qubits will be ...
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1 answer
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What is the structure of Qiskit's amplitude-encoded quantum circuit?

A problem that has been ignored before is that Ansatz does not know that classical data becomes quantum data. Although Qiskit provides the Initialize() function that can be initialized directly. I'm ...
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How can the result of 1 million transformations on a qubit be verified to be correct?

I tried to do almost a million transformations on a qubit. I made a three qubit circuit with equal superposition of |0> and |1> (using Hadamard gate) and on the first qubit (qubit 0), added one ...
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How to stretch duration of standard gates of an IBM Backend?

I want to stretch the duration of standard gates of an IBM backend to amplify noise (as proposed in one of the earliest implementations of zero noise extrapolation (ZNE) (https://arxiv.org/abs/1805....
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What can I use instead of mct (multi-controlled Toffoli)? (Grover's algorithm)

I implemented the general diffuser (for arbitrary qubits) in Grover's algorithm in terms of an Multi-controlled Toffoli (MCT) gate (it flips target when all controlled gates are 1). However, this gate ...
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Why a Fourier Adder Gives Multiple Faulty Results?

I followed this tutorial and wrote a code that implements the following circuit: By writing the following code: ...
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get_statevector() not working with Qiskit Aer's statevector simulator

I'm trying to understand how result.get_statevector() works. Using BasicAer, the following code gives the result for the statevector: ...
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1 vote
1 answer
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ModuleNotFoundError: No module named 'qiskit_aer'

I am trying to perform some noise simulations using the Aer Provider. I read through a tutorials here, but I am not able to really implement the qiskit_aer. When I ...
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Implementing QAOA Hamiltonian for MAX-3-SAT in Qiskit

I have read about how QAOA is used to tackle the MAX-CUT problem and wanted to test my understanding by trying to implement some code to approximate the MAX-3-SAT problem. To do so, I considered the ...
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1 answer
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Difference between run, measure, transpile, execute?

quite new to quantum computing and I have to do a small presentation on quantum gates using python code(notebook).Also, please review the small code I have written for its correctness. I have some ...
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Simple Maths Operators implementation in Quantum

I am a newbie in quantum programming and trying to learn implementing some simple classical programs in quantum, just as a starting point. The thing I am kind of struggling in is availability of ...
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What is the purpose of the various qiskit libraries? [duplicate]

I can't find much resources about how Qiskit API libraries are organised. We could see versions by using: ...
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QuantumKernel.construct_circuit:How to automatically build a quantum kernel circuit according to the QISKIT file?

This link https://qiskit.org/documentation/machine-learning/stubs/qiskit_machine_learning.kernels.QuantumKernel.construct_circuit.html#qiskit_machine_learning.kernels.QuantumKernel.construct_circuit ...
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An algorithm for solving LDEs: How find non-zero indices of Vs1 operator?

I am using qiskit to implement the second part of this algorithm which can be found on page 7: "$A$ is non-unitary" section of the appendix. Basically, it expands the solution of the ODE $x(...
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1 answer
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Building a realistic noise model in Qiskit

I am trying to build a realistic noise model in Qiskit for a quantum computer that might be available 2-3 few years from now on. I tried to start from an existing noise model generated from a fake ...
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How can I graph the time evolution of an initial state under a given hamiltonian in Qiskit?

I'm trying to compare the graphs of the time evolution of a state under the action of a given hamiltonian (Heisenberg, Ising). I have the graphs of the classical simulation using the ~ and @ ...
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1 answer
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AttributeError: 'list' object has no attribute 'values'

While implementing a code, getting the below error: ...
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3 answers
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What is the maximum number of qubits to execute a circuit on real hardware with IBM Quantum Experience and Qiskit?

I can't find anything that says about this. I know that on some simulators there are a limit of 32 qubits (quasi simulator) or more. But on real hardware ?
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How simulation of noisy quantum circuits is done in Qiskit using the statevector method

While performing VQE calculations of medium-sized molecules like H2O, using Qiskit AerSimulator with noise, I noticed that even for a large number of shots, the speed of simulation using statevector ...
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1 vote
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How MCMT is implemented in Qiskit, what is the initiution behind it?

I have read about and used the MCMT qiskit gate (Multiple Control Multiple Target). But I wonder how they have implemented it, how is a gate (like CCCZ for example) is decopmosed into basic gates and ...
2 votes
1 answer
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get.statevector() error: Failed to load qobj: Duplicate key "statevector" in save instruction

I'm building a mini tutorial to introduce the construction of composite systems using qiskit. While doing so I am demonstrating multiple ways to construct and view the statevector, but I have come ...
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Insufficient memory to run circuit using the statevector simulator

I am a newbie to quantum and have been trying qiskit library for learning quantum computing (in order to explore quantum effects on cryptography). I am basically ...
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is cirq suitable for simulation of quantum error correction?

I experimented with stim and qiskit for QECC simulations. They both have limitations : for example stim has no support for non-clifford operations (qiskit does); qiskit has no support for multiple ...
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1 vote
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How do I draw a multi control cz gate or do I have to make my own gate?

I want to build a diffuser and an oracle so that's why I wanted a multi control cz gate but I looked everywhere I didn't get any
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How to represent a statevector in Dirac notation form using Qiskit?

I am learning from qiskit textbook, and I was wondering how may I get a statevector of the following form: $$ \frac{\sqrt{2}}{2}|00\rangle + \frac{\sqrt{2}}{2}|10\rangle $$ If I run code for this in ...
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Building Unitaries in TSP Quantum Phase Estimation Qiskit?

In the paper [https://arxiv.org/pdf/1805.10928.pdf] 2 published by IBM, they use Quantum Phase Estimation to solve the TSP problem. I don't understand the reason why they can decompose the diagonal ...
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How to get more qubits, with less noise, with qiskit

I have a quantum ciruit, a qiskit application, that uses four qubits and has a depth of a few dozen operations (unitary transformation). It gives correct results when run on the simulator backend but ...
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How to run qiskit circuit in the cloud - qiskit runtime

Last night I created an IBM Cloud account. I can run the "sampler': ...
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how to solve the error given by backend=provider.get_backend('ibmq_vigo')

I try to run a quanum circuit with noise. I get an error at backend=provider.get_backend('ibmq_vigo'). I am not sure what causes the error. Could anybody help me ...
-1 votes
1 answer
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how to fix module not find error

how to fix 'module not find error' ModuleNotFoundError Traceback (most recent call last) Input In [4], in <cell line: 1>() ----> 1 import ...
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qiskit : how to measure multiple pauli strings

This seems like a basic operation, but I can't see how it's done in qiskit. The solution here Measuring tensor products of Pauli operators doesn't work anymore. I get an error "qiskit has no ...
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1 vote
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how to fix error 'QiskitBackendNotFoundError' [closed]

This is my code: from qiskit import IBMQ IBMQ.load_account() provider = IBMQ.get_provider('ibm-q') qcomp = provider.get_backend('ibmq_16_melbourne') ...
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1 vote
1 answer
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How to rewrite the quantum state to qubits?

I have a following state (indexing everything from 0 here) $$ | \psi \rangle = \frac{1}{\sqrt{2}} \left( | \uparrow_0 \downarrow_1 \rangle - | \downarrow_0 \uparrow_1 \rangle \right) $$ and I need to ...
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1 answer
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How does the Active Space Transform work theoretically?

I have a question about the ActiveSpaceTransformer which is used in vqe calculations for a molecule of LiH in Qiskit. In the documentation the inactive Fock operator is defined.I don't understand why ...
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1 answer
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$S^2$ expectation value of a circuit seems wrong

I need to rewrite a following circuit from Cirq to Qiskit with $2\varphi = \pi$. It's a circuit representing an initial state for VQE calculation. Considering, that ...
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1 vote
1 answer
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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 (...
1 vote
3 answers
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how to apply pauli string depending on multiple control qubits (qiskit or stim)

I read and re-read the documentation for MCMT and MCX and still can't figure out how to do this. For example I have 10 qubits $q_0,\cdots q_9$; I want to apply pauli string $X_2 Y_4 Z_5$ with control ...
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How to design the circuit of VQLS?

I am very confused about how to design the VQLS circuit. For example, I know the A is: X is pauli matrix. And how to add these three X pauli gates into circuit? I know the overall circuit should look ...
1 vote
1 answer
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qiskit transpile NameError

I am a beginner in Quantum Computing programing and I need HELP. I do not know why the Python or Qiskit does not recognize the "transpile" command? For example, ...
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2 votes
1 answer
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Automated conversion of QuantumCircuit in the Mathematica package QuantumFramework into Qiskit-code

Is it possible to automatically transform a quantum circuit, created in Wolfram's Mathematica (through the QuantumFramework package) into a qiskit code? What I thought of would be a package function ...
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1 answer
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qiskit-nature accessing circuit

There are some very nice examples on how to handle circuits using qiskit. However, once we get to the qiskit-nature documentation, it feels like a complete new world for the untrained eye. I am ...
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How to perform basic correction based on syndrome measurements in CSS codes

I'm trying to implement the rotated surface code with 9 qubits. I'm willing to perform one round of syndrome measurements, based on which corrective X and Z gates will be applied on the 9 qubits. I'd ...
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1 answer
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How to use control logic in MCPPhaseGate

I need help with the MCPhaseGate. I am not able implement the control logic (i.e, the control function)with MCPhase gate similar to the RXgate shown below. It would be great help if someone can help ...
1 vote
1 answer
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Going from projective measurement to unitiary operators for qiskit

I have a solution to the Peres-Mermin magic squares game (Wikipedia quantum pseudo-telepathy) I simulate the six measurements using projective (non-unitary) measurement operators like in Nielson and ...
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Qiskit's "Pulse" module: Sending a pulse to a qubit using a mock backend

I'm trying to sende a pulse to a qubit on qiskit. I have succeeded in doing so when using a real backend on qiskit. But the trouble is, I can't get it to work on a mock backend. I have tried a bunch ...
1 vote
1 answer
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Get state vectors in qiskit at any time in a circuit created with initialize() and decompose()

How can I get the state vectors at any point in the circuit if after these instructions it points to end. ...
1 vote
1 answer
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Is there any alternative for `qiskit.initialize` in aws braket for running circuit on `Ionq Device`?

I'm trying to run a quantum circuit created in Qiskit, on Ionq Device using qiskit_braket_provider. Getting some error while transpiling the circuit because circuit ...
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