Questions tagged [qiskit]

Quantum Software Development Kit for writing quantum computing experiments, programs, and applications. If appropriate, also use the [programming] tag.

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Is it possible to run a general implementation Shor's algorithm on a real IBM quantum computer at least for N = 15?

I need to make a general implementation of Shor's algorithm that factors, at least, N = 15. I have been able to perform an implementation that works in simulators, with ProjectQ, but when running it ...
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87 views

Graphing the decoherence of qubits being used to perform an algorithm

How would I be able to graph the decoherence of qubits being used to perform an algorithm? I'm working with the IBMQ Qiskit framework and I'm trying to write a program that allows me to find the ...
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1answer
117 views

Use Qiskit in other programming languages (C#, JavaScript and Lua)

I am exploring using Qiskit in other programming languages for game development, such as C# (for Unity game engine), JavaScript (Phaser.io) and Lua (LÖVE2D). Is there a general way to call Qiskit ...
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43 views

Vary parameter between shots

Is it possible to tell Qiskit to execute a parameterized gate where the parameter varies between shots? Let's say, for whatever reason, I'd like to speed up the dephasing of a qubit during a run. I ...
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148 views

Problem with measurement error mitigation using VQE

I am attempting to mitigate measurement error while running on one of IBM's real devices and am doing so by passing CompleteMeasFitter into ...
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100 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 ...
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2answers
41 views

IBMQfactory._initialize_providers Error

After a successful first run without problems, I found that I cannot connect any longer. Code: ...
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0answers
60 views

How does batching work in the optimizer loop of the VQC algorithm in Qiskit Aqua?

I've playing around with a binary classification problem with a dataset of size 1000 examples and 5 features. I'm using the VQC algorithm from the Qiskit package the that uses a feature map and a ...
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58 views

`execute()` hangs and eats memory

Used memory-profiler to check why I get memory spikes in what I though were small circuits. The circuit itself is constructed using ...
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218 views

Is there a way to develop a multiple controlled X or Z gate on Qiskit without using ancillary qubits?

I know for instance I can derive a cccX gate using 2 Toffoli gates on 5 qubit wire or ccccX with 3 Toffoli gates and 7 qubits and so on. you will notice the depth is increasing as the number of ...
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280 views

Measuring Coherence Length for T1 and T2 values with IBMQ Experience

So I'm currently working on a little program to measure how long the coherence time of a qubit is. Basically the idea is to initialise a qubit with a X or H gate then stick in a varying amount of ...
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70 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 ...
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113 views

Measurement inconsistency in Qiskit

I am using Qiskit in an algorithm. In the end, I am measuring exactly a register of 4 qubits but the histograms show states with 5 qubits. This is the code I used: ...
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75 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 $\...
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73 views

What are reasonable noise/dephasing parameters for QuEST to emulate state-of-the-art quantum computers?

The QuEST code allows for simulation of quantum computers taking dephasing and depolarizing noise into account via one and two qubit dephasing and depolarization. What are realistic parameters for ...
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496 views

Qiskit SDK problem

So I am getting this error when I fire the command on Ipython or Jupyter Notebook ...
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477 views

Qiskit Python program cannot connect to QE API

I am just getting started with Qiskit and IBM Quantum Experience, so please forgive my newby question. I have a IBM Quantum Experience account and I generated an API token. I used the generated ...
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29 views

How to do error mitigation on the ibmq_16_melbourne?

I'm trying to make a calibration matrix using CompleteMeasFitter as in here on IBMQ Melbourne, but I need to use all 15 qubits, which mean it has to run 32768 calibration circuit, far exceeding the 75 ...
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31 views

How do I optimize HHL algorithm in Qiskit?

How do I optimize HHL algorithm in Qiskit? I tried to follow this tutorial on HHL in Qiskit. My project requires solving a very specific type of linear equations $Ax=b$ like the one below. ...
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47 views

How to construct a multi-qubit controlled rotation with variable angle?

I'm trying to construct a circuit that performs the quantum transformation : Where $f$ is some function. Is there a way to do it without going through every possible value of $i$ ?
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0answers
36 views

IBMQJob.result() returns KeyError: 'qObjectResult'

I'm running tomography job like I have done many times before. I send the job, and the job.status() is 'DONE'. But when I ask for ...
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0answers
27 views

How to simulate spin-1 systems with qiskit or on the IBMQ platform?

I am wondering how to simulate spin-1 systems with qiskit or on the IBMQ platform? I want to initialize a qudit (a spin-1 system), and then define the usual operations (such as Sx, Sy, and Sz) on the ...
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40 views

Easiest hash function to implement on Qiskit

Trying to build an Oracle circuit for Grover's algorithm that will try to find a desired input in order to get a certain output of a hash function. Was wondering if there were any 4 or 8 bit hash ...
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111 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 ...
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83 views

Simulation for the [5,1,3] stabilizer code in Qiskit

Sorry that I keep asking questions for the same subject. It is driving me crazy. I have followed the [5,1,3] stabilizer code circuit designed by Gottesman in page 35 in his paper (also illustrated in ...
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3answers
122 views

Pauli I in eoh procedure doesn't become a global phase gate in qiskit evolution_instruction method. Possible consequences

If one has two qubits in arbitrary stats and wishes to apply a controlled version of some global phase gate $P(\varphi) = \begin{pmatrix} e^{i\varphi} & 0 \\ 0 & e^{i\varphi} \end{pmatrix}$ ...
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2answers
123 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 ...
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74 views

Is it possible to simulate or replicate a cryptographic algorithm using Qiskit?

I would like to know if it is possible to recreate or simulate a cryptographic encryption algorithm like DES or AES using the quantum computing platform Qiskit from IBM?
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81 views

Running HHL tutorial on real backend

I tried to follow the HHL tutorial. Since the 8x8 problem is not realistically simulable (I stopped after a few minutes), I tried to make it run on another backend, starting on the easiest example: <...
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0answers
145 views

Error ERROR_TRANSPILING_JOB when trying to simulate the circuit

I'm trying to implement an algorithm (https://dl.acm.org/citation.cfm?id=1128034, basically a simple Grover Algorithm in which the oracle is made of a Fitness operator- some CNOT gates- and 2 adders) ...
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0answers
50 views

Hybrid classical-quantum linear solver based on the Neumann-Ulam method

I read this article on quantum linear solver based on the Neumann-Ulam method (here is a lesson about it). But the article has not a lot of details. Therefore I don't understand what is the algorithm ...
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14 views

Am I doing anything wrong when trying to calculate the expectation value in Qiskit on the real hardware?

I am trying to use the method of calculating the expectation values of Pauli operators in Qiskit which I found here. However, the results obtained via IBMQ sampling differ significantly from the exact ...
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1answer
70 views

Why after transpiling a Qiskit circuit we obtain a different result?

I am trying to obtain the correct circuit transpiled for the ibmq_london device, as I want to know what the real gates applied in the quantum computer are. I am implementing the QFT circuit for 5 ...
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1answer
31 views

What is the difference between Qiskit execute and the IBMQJobManager?

I was researching how to submit multiple pulse schedules/circuits in the same job and came across 2 methods: Executing Experiments with qiskit.execute and ...
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84 views

How can I initialize a state with chosen amplitudes in Qiskit?

I was trying to initialize to an arbitrary state of n qubits with the initialize() from Qiskit but it doesn't generate a state with the same amplitudes passed as an ...
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25 views

How to ignore spins is Qiskit chemistry package?

Is it possible to use built-in qiskit.chemistry tools, such as VQE, UCCSD, etc., without ...
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0answers
48 views

ibmq_qasm_simulator from IBMQ provider and qasm_simulator from Aer provider gives different results

I'm running an experiment first on qasm_simulator backend from Aer provider and the most frequent result is the correct one with ...
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52 views

Creating Bell States with CNOT conditioned to the control qubit being set to zero

I was using qiskit to generate all of the Bell States. I created the following circuits for each state: $|\Phi^+\rangle :$ $|\Phi^-\rangle :$ $|\Psi^+\rangle :$ $|\Psi^-\rangle :$ The $|\Psi^\pm\...
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0answers
23 views

Error in qiskit.aqua.operator

I want to implement this thing: Operator([[3, Pauli([1,0,0], [0,0,0])], [2, Pauli([0,0,0],[0,0,3])]]) But while doing this there is an error in ...
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16 views

Confusion regarding subset_fitter() functionality from CompleteMeasurementFitter() in Qiskit.Ignis

I have been experimenting with the measurement mitigation module in Qiskit Ignis lately. I determined a calibration matrix $M$ with the help of ...
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0answers
59 views

Qiskit not installing properly on pyCharm CE

I have installed qiskit through my terminal using pip3 install qiskit. But when I try to import all from it in my coding software, it returns a M...
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0answers
41 views

How can I run programs in test folder Github Qiskit

I am new to GitHub/Python - please tell me how can I run programs in https://github.com/Qiskit/qiskit-aqua/tree/master/test and its sub directories in Jupyter. I am connected to IBM Q Expereince. I am ...
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1answer
46 views

qiskit: IQFT acting on subsystem of reversed-ordered qubits state

I have a state psi as an ndarray of shape (2 ** 3,) s.t. psi[0]= amplitude of 000 ...
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0answers
37 views

Loading old results for Data reprocessing

I want to process some old data again. How do I load old data retrieved from IBM-Q into a new program? I've downloaded the relevant .json file, but I don't know how to use it like I would have a new ...
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46 views

Implementing QFT

I would like to know if there is a way to: Implement Quantum 'Functions' e.g the QFT of QFT* containing several single-qubit operations? Implement such operations on an arbitrary number of qubits and ...
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0answers
208 views

Decomposition of an arbitrary gate using given matrix in Qiskit

If I have an arbitrary non-unitary matrix of say $$ U = \begin{pmatrix} 1.5 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1.6 \\ 0 & 0 & 1 & 0 \\ 0 & 1 & 0 & 0 \\ \end{...
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1answer
59 views

from qiskit.aqua import… ImportError: DLL load failed: The specified module could not be found

Dear team and developers. I am using qiskit on Python 36, windows 64bits I have the same identical problem of Import from qiskit-aqua error But the suggested solution (installing Numpy+mkl, I did ...
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0answers
62 views

Grover's algorithm for 3SAT problem gives erroneous results

I'm writing a code in python with qiskit that implements Grover's algorithm to solve the 3-SAT problem, but when I run it it doesn't give the correct annswer. I've checked the circuit with the ...
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102 views

A question about qiskit's WeightedPauliOperator.evolve method for IPEA (IQPE) implementation

I'm doing an implementation/tutorial of the iterative phase estimation algorithm (IPEA) and have a problem. My Hamiltonian is a diagonal matrix $H = \begin{pmatrix} E_1 & 0 \\ 0 & E_2\end{...
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37 views

OpenPulse: Where to get current pulse definitions for standard gates?

Is backend.defaults().cmd_def and backend.defaults().pulse_library kept updated regularly? Is this the correct place to pull the best calibrated pulses for the standard gates? I am working on a ...