Questions tagged [ibm-q-experience]

Use this tag for questions about IBM's Quantum Service - Circuit Composer & Quantum Lab. DO NOT use this for questions about general Qiskit issues. As of August 2020, there are 20 processors on the IBM Q Experience ranging from 5 to 53-qubits. Note: Some systems are only available to hubs, partners, and members of the IBM Q network.

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IBM Circuit Composer pane is blank

I'm new to IBM Quantum Experience. When I initially create a circuit using the composer, all is well, but when I save the circuit and open it again, the composer window is blank - no gates or wires. I ...
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Implementing B92 protocol on IBM Qx

I wanted to implement the B92 protocol on IBM Qx. Implementing the protocol would require that a particular qubit should not be measured when using a particular base i.e. there should be no output at ...
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Many jobs hanging after creating

I am running a VQE calculation running from a cluster using nohup. However, some of my jobs keep hanging with 'creating' and therefore my VQE is not converging/not working. However, at the same time,...
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Tensored vs ordinary measurement mitigation runtime

My experiments show that the runtime of actually applying the measurement filter matrices to circuit execution results is much slower for tensored mitigation than ordinary mitigation. Tensored ...
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2answers
755 views

Trying to build a circuit for quantum teleportation on IBMQ I get ERROR_RUNNING_JOB error

I am trying to build a circuit for quantum teleportation. On the simulator, everything runs fine and according to expectations, however, I am not able to run the algorithm on the real quantum ...
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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 ...
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1answer
264 views

Attribute error in Qiskit

Tried executing plot_histogram(result.get_counts(circuit)) where result has the job result and circuit is the Quantum circuit But an attribute error hits every ...
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1answer
86 views

Existing measurement error mitigation

Does IBM compute a measurement error mitigation calibration matrix that can be accessed from its device properties or somewhere else? Or does the user have to do that every time?
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1answer
117 views

Error on loading account with qiskit: “TypeError: __init__() missing 1 required positional argument: 'url'”

We are using an open account. We can not load the account even when we use the code on new notebook. The error message is: ...
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1answer
195 views

How to parallelly run a quantum circuit on IBMQ?

I am trying to implement the following circuit and my code is The above circuit has size 5 and depth 3. My question is, how can I run the circuit parallelly. I mean, the gate ...
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3answers
155 views

IBM 53 qubit cloud access

IBM announced a 53 qubit chip. Will the advertised chip be available for non-paying users, or only to IBM clients?
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1answer
60 views

Is IBM Q composer using little-endian representation for multi-qubit states?

I am still confused when I am trying to use the IBM Q composer to reproduce some quantum circuits I found in different papers, and I am wondering if it is because there are two ways to represent a ...
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Transfer trained machine learning model

I know just the basics of quantum computer i.e. superposition, entanglement, gates and few other kinds of stuff. Now the question is it possible to transfer a trained machine learning model from IBM ...
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2k views

What is a “barrier” in Qiskit circuits?

I just started studying IBM Qiskit, and cannot find details about the barrier method on the QuantumCircuit class. It is shown in the circuit drawing, but I never heard about it after reading quantum ...
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What is ''524 Server Error''?

When running my code, sometimes I find this 524 Server Error: Origin Time-out for url and then my code stop. The error is in ...
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721 views

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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3answers
150 views

How many classical registers are there on (IBM) quantum computers?

I have a circuit where I only use 3 qubits but need to utilize hundreds of classical registers. My questions are: what is the maximum number of classical bits on the current IBM Qs? What is the ...
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2answers
122 views

How to unpickle a Result object returned by an IBMQ experiment?

I have executed an experiment using IBMQ and receive a Result object. I am writing the ASCII repr of the result with f.write(res)...
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163 views
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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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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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1answer
408 views

Backend Warning: The skip Qobj validation does not work for IBMQ provider. Disable it

I am using QAOA to solve the max-cut problem. On my machine, 10 qubits already takes a minute or two to simulate. I'm hoping that the ibmq-qasm-simulator could simulate 32 qubits faster than my laptop ...
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1answer
77 views

Can we simulate quantum many-body systems with IBMQ Experience?

Consider physical systems such as electrons in metals, or Bose-Einstein condensates, or any crystal, which are realised in the real three-dimensional space. If we want to simulate these systems on a ...
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1answer
752 views

IBMQ.load_account from stored ACCOUNT is failing on Qiskit 0.9.0

The following statement is causing an error in Qiskit Version 0.9.0: provider = IBMQ.load_account() Error Message: ...
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1answer
1k views

Why use U2 and U1 gate in IBM quantum computers?

I was wondering why IBM's computer were using U1 and U2 gates as part of there basis gates since as I understood, they are particular cases of the U3 gate. Why not just use U3 gate instead ? Thanks ...
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3answers
428 views

Access results from an experiment without having to run the script again

I have ran an experiment in one of the IBM processors and the work has finished. However, I can not obtain the data as histograms or counts in the qiskit notebook because the experiment was concluded ...
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2answers
121 views

Software for Quantum Computing

From what I read classical computing evolved so quickly because of the funding-applications cycle. Even though the cost to make denser IC's was increasing rapidly, the applications were also getting ...
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1answer
519 views

What is the IBM Q credits?

I find in this link that "A User has a maximum of 15 credits, and these credits are replenished upon the greater of 24 hours or when your execution has run off the queue." But what is credit? Is ...
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361 views

Job execution issue while using IBMQ Experience

I am trying to run QSVM algorithm on the IBMQ backend devices using the API_TOKEN. Below is the snippet of the code that I am running. The code fails the validation test and throws an exception after ...
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1answer
292 views

How do I interpret the readout error for a quantum computer?

For example, the ibmqx2 computer has the most recent readout error of $4.40 \cdot 10^{-2}$. Does this mean per 1000 measurements, 44 faulty results exist?
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166 views

Gate error in IBM-Q simulator vs real backend

Does the simulator of the IBM-Q supercomputer involves a CNOT gate error rate ? What are the main differences reasons in outcome between simulators and real backends in IBM-Q ? Best,
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1answer
224 views

Chose how to map virtual qubits to physical qubits

I'm currently trying to specify an initial_layout for a circuit on a IBM Q device. Looking at the device's topology I would like to use the less noisy qubits in order to have the best performance. ...
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1answer
129 views

How is it possible to perform a c-not on 4 qubits using the same control qubits on IBM Q computers?

I was wondering after seeing ibmq_16_melbourne layout how it is possible to perform this circuit : It seems when looking at ibm q computers that a qubits can at max target 3 qubits because the arrow ...
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274 views

Please help: get_statevector gives wrong result in qiskit

I simulated the circuit below in qiskit and used the statevector simulator to extract the statevector: The resulting statevector that it gave me was: array([ 0.5+0.j, -0.5+0.j, 0.5+0.j, 0.5+0.j]) ...
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1answer
244 views

ERROR_RUNNING_JOB with 32 qubit circuit running on ibmq_qasm_simulator backend

I recently made a quantum circuit that uses 32 qubits and try to run it on IBM Q Experience qasm_simulator backend. But it always ends with ERROR_RUNNING_JOB. ...
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2answers
74 views

Measuring the effect of energy relaxation with IBMQ Experience

I want to investigate the effect of the decoherence time on a qubit, and I followed the tutorial here. https://quantumexperience.ng.bluemix.net/proxy/tutorial/full-user-guide/002-...
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1answer
74 views

How call from IBM Q Experience (Jupyter Notebook) cplex

I have the latest version of cplex (12.9) installed on my computer. I use it very well with Jupyter notebook, but in IBM Q Experience, I did not get way to call it. IBM Q Experience warns me that the ...
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70 views

edit a program on IBM Q experience

Can I edit a program with python numpy and scipy and of course qiskit in the IBM Q experience, using code? (I am not interested in drugging gates) and I can't find the way to edit my own program
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414 views

IBM Quantum Experience: simulation not running on IBMQ_16_melbourne

What is this dedicated use of IBMQ_16_melbourne? I am trying to run a simulation but it is not running. Is there any way to run the simulations? When is the backend coming online again for normal ...
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1answer
276 views

Problem with initial_layout on Qiskit/IBMQ: 'Not enough qubits in CouplingGraph'

I am trying to run an execution on IBMQx2 where I can specify the physical qubits to which I apply gates. The execution without the initial_layout runs fine, but ...
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1answer
633 views

How do I check my remaining IBM Q credits?

I've already tried the approach in this answer, but I'm getting this error: ...
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2answers
184 views

How do I get out 2 measurements from the same execution on Qiskit?

Here's my circuit, trying to checkout the effect of measurement on the IBM Q circuit. Here you can see I do 2 different measurement at different time, and I hope to be able to see both results. ...
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108 views

Number of Shots always 1024/or nothing (IBM q experience)

I have been running some simple "Hello Quantum World" code and every time I try to run it on 4096 shots or 8192 shots, the results always show as if I ran the code on 1024 shots (or in the most recent ...
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1answer
118 views

How to upload .py file to new online Qiskit Notebook

I'm trying to run a program in the Qiskit Notebook on the IBMQ Experience. I need to import some .py files that I've done in order to run my main program but the notebook won't accept .py files. I've ...
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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 ...
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1answer
562 views

What does a quantum circuit look like after qiskit.compile() has been applied?

IBM-Q states that the real devices available for public use have a set of "basis" gates consisting of u1,u2,u3 and CNOT. However in Qiskit the circuit can be built with many gates which are not ...
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160 views

Having trouble communicating with the IBM Q Experience REST API

I have started using IBM's Q Experience and I am trying to obtain an access token in order to communicate with the REST API. I understand that I can use my API token to obtain authorization by sending ...
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32 views

Bug report bug report? [duplicate]

The full user guide here states "If you find any bugs, please report them with our bug tracker, accessible via the little bug icon in the lower right-hand corner of each page." However, I was unable ...
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1answer
70 views

Bug in IBM backend?

I was trying to see what IBM would do under the hood with a CCNOT gate. Something appears to be erroneous with the run. The circuit above should produce state 11100 with 100% probability, as ...
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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 ...

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