Questions tagged [qiskit]

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

114 questions with no upvoted or accepted answers
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59 views

Is there a general order finding quantum algorithm for a given a and N?

I'm trying to construct a general circuit for Shor's algorithm in Qiskit. I understood the later parts of the circuit (inverse QFT and QPE), but can't really understand the order finding. For example, ...
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0answers
61 views

Form and effect of the intrinsic Hamiltonian on the IBM machines

I want to understand the form of the intrinsic Hamiltonian of the IBM machines, such as ibmq_16_melbourne, and how this affects the data I get out when waiting ...
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1answer
50 views

What is the executable opcode for Qiskit quantum hardware, as the quantum circuits or the transpiled/compiled QObj/ QASMQObj are assembly languages?

When we write a QASM code or build quantum circuit on Qiskit GUI, it converts it into QObj/QASMQObj (refering paper Qiskit Backend Specifications for OpenQASM and OpenPulse Experiments) or its ...
4
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1answer
136 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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0answers
50 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 ...
4
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0answers
181 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 ...
4
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0answers
106 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 ...
3
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1answer
46 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. ...
3
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0answers
90 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 ...
3
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0answers
67 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 ...
3
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0answers
309 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 ...
3
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0answers
71 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 ...
3
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120 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: ...
3
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0answers
78 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 $\...
3
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0answers
74 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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508 views

Qiskit SDK problem

So I am getting this error when I fire the command on Ipython or Jupyter Notebook ...
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0answers
494 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 ...
2
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1answer
70 views

What is the best way to handle parametric circuits in Qiskit?

What is the best way to handle parametric circuits in Qiskit? When I create a variational form like TwoLocal and then do ...
2
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1answer
32 views

Optimize chains of single-qubit u1, u2, u3 gates by combining them into a single gate in Qikist

Can anyone explain how Qiskit does the merging of single-qubit gates for the purpose of optimization? u1(lambda1) * u1(lambda2) = u1(lambda1 + lambda2) ...
2
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1answer
57 views

Is there a function in Qiskit to measure tensor products of Pauli operators?

Is there a function in Qiskit similar to this function in Q# which measures strings of Pauli operators applied to different qubits?
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0answers
100 views

My Bloch sphere/ qsphere is appearing as an ellipse/oval

I tried to plot a Bloch vector. However, my Bloch sphere is appearing as an ellipse/oval instead of a circle. I am having the same issues with qsphere also. instead of ...
2
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0answers
40 views

What is the buffer time between gates of the ibmq_essex in nanoseconds?

This is a question that I asked on Qiskit ignis section of slack, with a very interesting answer by A Kapila, but I also need to get a short answer in nanoseconds. I want to evaluate decoherence in ...
2
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1answer
59 views

VQE jobs do not appear in queue

I am trying to calculate the ground state energy of some simple molecules using 'MolecularGroundStateEnergy' tools in qiskit. When I run the calculations for very small molecules (e.g. H2, HeH+) the ...
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0answers
38 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 ...
2
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0answers
56 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 ...
2
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0answers
28 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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0answers
46 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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0answers
145 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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0answers
90 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 ...
2
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3answers
131 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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0answers
52 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 ...
2
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2answers
156 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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0answers
79 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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0answers
88 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
147 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) ...
2
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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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1answer
39 views

Unable to instantiate provider for research account locally

When I run IBMQ.load_account(). I have the error information: ...
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0answers
30 views

Deriving Expression For QAOA Optimal Trial State Parameters

I am going through the QAOA section in the Qiskit Textbook - QAOA and am stuck in one of the steps. In section 5.2, the method for getting the Optimal Trial State Parameters are discussed. I do not ...
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0answers
24 views

What is the advantage of QSVM over the classical SVM?

I am mainly talking about QSVM from Qiskit (https://qiskit.org/documentation/stubs/qiskit.aqua.algorithms.QSVM.html#qiskit.aqua.algorithms.QSVM) versus a classical SVM. Is it just a time complexity ...
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1answer
37 views

Can I append gates in a certain position in a Qiskit circuit

I have a question regarding modifying Qiskit circuits. I have a set of circuits that are pretty similar to each other. The only difference being some gates in the beginning of each circuit. I was ...
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1answer
67 views

controlled-Z rotation gates in symmetrical fashion

I was going through the qiskit textbook and in this chapter, i came across a statement under the topic "Kickback with the T-gate" related to the Controlled-Z gate that "the controlled-...
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0answers
50 views

Changing the Basis

I am attempting to use a VQE algorithm to find the ground state of a deuterium nucleus by applying a constructed hamiltonian to an ansatz state with one parameter created by a circuit. While I am ...
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0answers
48 views

Help Understanding Line in Source Code

In Qiskit's implementation of the HHL algorithm, they have the following line at the end of their code that allows them to compute the global phase we need to add on to the solution. ...
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0answers
21 views

How to implement gate error mitigation in Qiskit?

I have been using the Ignis module for performing error mitigation but it accounts only for the measurement errors. For this reason, I want to know if there is some way to perform gate error ...
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1answer
39 views

Qiskit IBMQ.load_account fails on version 0.20.0

So when trying to load my account I get this error: ...
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0answers
75 views

Problem with installing Qiskit on Android with Termux emulator

Termux has some issues with cmake, therefore qiskit-aer-0.5.2 installation returns error 1. ...
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0answers
27 views

What is the maximum circuit depth for Qiskit Aer Simulator?

I'm running some simulator circuit on my computer, and I see that (using 3 qubits, and thousands of classical registers), the max cap seems to be about qc.depth() ...
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1answer
69 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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0answers
52 views

QFT on timeseries Data and compare results with classical FFT

Intention - To learn and apply QFT on time-series data and compare the result with classical FFT. Data Used - Small timeseries data of 16 points - ...
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0answers
27 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 ...