Questions tagged [ibm-q-experience]

Use this tag for questions about IBM's quantum processors which are accessible online. DO NOT use this for questions about general Qiskit issues. As of July 2018, there are five processors on the IBM Q Experience: two 5-qubit processors, one 16-qubit processor and two 20-qubit processors (only available to hubs, partners, and members of the IBM Q network).

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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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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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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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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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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
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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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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
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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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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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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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112 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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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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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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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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121 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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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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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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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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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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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
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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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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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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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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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280 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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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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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
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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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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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109 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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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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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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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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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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1answer
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IBM Slack links broken

Does anyone know where I can find working Slack invite links to any of IBM's Slack pages? The Slack links on this support page are all broken. Thank you.
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1answer
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Experiments stuck on VALIDATING ibmq_16_melbourne

Since yesterday I'm trying to run on the new composer (quantum-computing.ibm.com) both new experiments (never run before) and older experiments (that have been successfully run and completed some ago) ...
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1answer
56 views

Back End for Reset Gate

IBM's simulator allows the use of a reset gate ($|0\rangle$ gate) however when I try to run a circuit using this gate on the hardware it fails to execute. Is there a plan to physically realize this ...
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1answer
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Weeding out qubit states with leftmost qubit as 1

Need help! I was working on a project when I required to use a projection operator. For an example case, I have the Bell state, $$|\psi\rangle = \frac1{\sqrt2}\left(\color{blue}{|0}0\rangle+|11\rangle\...
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Visualizer error in IBM Q Experience Beta

I am noticing some erroneous behavior coming from the visualizer in some circuits I was running. I am not sure how widespread the issue is, but see the attached image for some strange behavior with ...
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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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How to implement the XY Heisenberg interaction using IBMQ and Qiskit?

A possible way to implement the 2 qubit Heisenberg XYZ model using a Quantum computer is to decompose the Hamiltonian as follows: $$H_{XYZ} = H_{XY} + H_{YZ} + H_{XZ}$$. In this case, these operators ...
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1answer
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2-qubit QFT in IBMQ: controlled phase rotation

I've started getting into quantum computing in the last few days. As part of the learning, I've figured it would be fun to implement some circuits on IBMQ Experience as I learn. So now I'm stuck with ...
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IBM Q devices scheduling of gates with different durations

I was trying to figure out how scheduling works in IBM devices. The thing that's bugging me is that in the quantum computer implementations I had seen before, the cycle concept is used. Say, for ...
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1answer
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How to define custom controlled unitaries in OPENQASM 2.0?

According to the OPENQASM 2.0 documentation, it's possible to define custom unitary gates using the format: gate name(params) qargs { body } where the optional ...
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Implementing Deutsch's problem on IBM Q composer

I tried to implement the Deutsch's problem on IBM Q but didn't get the results as expected. So here is the circuit for the Deutsch algorithm and this is my implementation on the composer: so let me ...
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How to run quantum SVM algorithm from Qiskit in real IBM Quantum Computer using IBMQ?

I'm trying to run QSVM algorithm in IBMQ experience, want to run in one of those real quantum computers. ...